Note: Descriptions are shown in the official language in which they were submitted.
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SLURRY DISTRIBUTOR WITH A WIPING MECHANISM, SYSTEM, AND METHOD
FOR USING SAME
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present patent application claims the benefit of non-provisional
patent
application 13/659,516, filed October 24, 2012, entitled "Slurry Distributor,
System,
and Method for Using Same" and continuation-in-part patent application
13/844,364
filed March 15, 2013 entitled "Slurry Distributor with a Wiping Mechanism,
System
and Method for Using Same."
[0002] All of the foregoing related applications are incorporated in their
entireties
herein by this reference.
BACKGROUND
[0003] The present disclosure relates to continuous board (e.g., wallboard)
manufacturing processes and, more particularly, to an apparatus, system and
method for the distribution of an aqueous calcined gypsum slurry.
[0004] It is well-known to produce gypsum board by uniformly dispersing
calcined
gypsum (commonly referred to as "stucco") in water to form an aqueous calcined
gypsum slurry. The aqueous calcined gypsum slurry is typically produced in a
continuous manner by inserting stucco and water and other additives into a
mixer
which contains means for agitating the contents to form a uniform gypsum
slurry.
The slurry is continuously directed toward and through a discharge outlet of
the
mixer and into a discharge conduit connected to the discharge outlet of the
mixer.
An aqueous foam can be combined with the aqueous calcined gypsum slurry in the
mixer and/or in the discharge conduit. The stream of slurry passes through the
discharge conduit from which it is continuously deposited onto a moving web of
cover sheet material supported by a forming table. The slurry is allowed to
spread
over the advancing web. A second web of cover sheet material is applied to
cover
the slurry and form a sandwich structure of a continuous wallboard preform,
which is
subjected to forming, such as at a conventional forming station, to obtain a
desired
thickness. The calcined gypsum reacts with the water in the wallboard preform
and
sets as the wallboard preform moves down a manufacturing line. The wallboard
preform is cut into segments at a point along the line where the wallboard
preform
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has set sufficiently, the segments are flipped over, dried (e.g., in a kiln)
to drive off
excess water, and processed to provide the final wallboard product of desired
dimensions.
[0005] Prior devices and methods for addressing some of the operational
problems associated with the production of gypsum wallboard are disclosed in
commonly-assigned U.S. Patent Nos. 5,683,635; 5,643,510; 6,494,609; 6,874,930;
7,007,914; and 7,296,919, which are incorporated herein by reference.
[0006] The weight proportion of water relative to stucco that is combined
to form a
given amount of finished product is often referred to in the art as the "water-
stucco
ratio" (WSR). A reduction in the WSR without a formulation change will
correspondingly increase the slurry viscosity, thereby reducing the ability of
the slurry
to spread on the forming table. Reducing water usage (i.e., lowering the WSR)
in
the gypsum board manufacturing process can yield many advantages, including
the
opportunity to reduce the energy demand in the process. However, spreading
increasingly viscous gypsum slurries uniformly on the forming table remains a
great
challenge.
[0007] Furthermore, in some situations where the slurry is a multi-phase
slurry
including air, air-liquid slurry separation can develop in the slurry
discharge conduit
from the mixer. As WSR decreases, the air volume increases to maintain the
same
dry density. The degree of air phase separated from the liquid slurry phase
increases, thereby resulting in the propensity for larger mass or density
variation.
[0008] It will be appreciated that this background description has been
created by
the inventors to aid the reader and is not to be taken as an indication that
any of the
indicated problems were themselves appreciated in the art. While the described
principles can, in some aspects and embodiments, alleviate the problems
inherent in
other systems, it will be appreciated that the scope of the protected
innovation is
defined by the attached claims and not by the ability of any disclosed feature
to solve
any specific problem noted herein.
SUMMARY
[0009] In one aspect, the present disclosure is directed to embodiments of
a
slurry distribution system for use in preparing a gypsum product. In one
embodiment, a slurry distributor can include a feed conduit and a distribution
conduit
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in fluid communication therewith. The feed conduit can include a first feed
inlet in
fluid communication with the distribution conduit and a second feed inlet
disposed in
spaced relationship with the first feed inlet and in fluid communication with
the
distribution conduit. The distribution conduit can extend generally along a
longitudinal axis and include an entry portion and a distribution outlet in
fluid
communication therewith. The entry portion is in fluid communication with the
first
and second feed inlets of the feed conduit. The distribution outlet extends a
predetermined distance along a transverse axis, which is substantially
perpendicular
to the longitudinal axis.
[0010] In other embodiments, a slurry distributor includes a feed conduit
and a
distribution conduit. The feed conduit includes a first entry segment with a
first feed
inlet and a second entry segment with a second feed inlet disposed in spaced
relationship to the first feed inlet. The distribution conduit extends
generally along a
longitudinal axis and includes an entry portion and a distribution outlet in
fluid
communication with the entry portion. The entry portion is in fluid
communication
with the first and second feed inlets of the feed conduit. The distribution
outlet
extends a predetermined distance along a transverse axis. The transverse axis
is
substantially perpendicular to the longitudinal axis. The first and second
feed inlets
each has an opening with a cross-sectional area. The entry portion of the
distribution conduit has an opening with a cross-sectional area which is
greater than
the sum of the cross-sectional areas of the openings of the first and second
feed
inlets.
[0011] In other embodiments, a slurry distributor includes a feed conduit,
a
distribution conduit, and at least one support segment. The feed conduit
includes a
first entry segment with a first feed inlet and a second entry segment with a
second
feed inlet disposed in spaced relationship to the first feed inlet. The
distribution
conduit extends generally along a longitudinal axis and includes an entry
portion and
a distribution outlet in fluid communication with the entry portion. The entry
portion is
in fluid communication with the first and second feed inlets of the feed
conduit. Each
support segment is movable over a range of travel such that the support
segment is
in a range of positions over which the support segment is in increasing
compressive
engagement with a portion of at least one of the feed conduit and the
distribution
conduit.
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[0012] In another aspect of the present disclosure, a slurry distributor
can be
placed in fluid communication with a gypsum slurry mixer adapted to agitate
water
and calcined gypsum to form an aqueous calcined gypsum slurry. In one
embodiment, the disclosure describes a gypsum slurry mixing and dispensing
assembly which includes a gypsum slurry mixer adapted to agitate water and
calcined gypsum to form an aqueous calcined gypsum slurry. A slurry
distributor is
in fluid communication with the gypsum slurry mixer and is adapted to receive
a first
flow and a second flow of aqueous calcined gypsum slurry from the gypsum
slurry
mixer and distribute the first and second flows of aqueous calcined gypsum
slurry
onto an advancing web.
[0013] The slurry distributor includes a first feed inlet adapted to
receive the first
flow of aqueous calcined gypsum slurry from the gypsum slurry mixer, a second
feed
inlet adapted to receive the second flow of aqueous calcined gypsum slurry
from the
gypsum slurry mixer, and a distribution outlet in fluid communication with
both the
first and the second feed inlets and adapted such that the first and second
flows of
aqueous calcined gypsum slurry discharge from the slurry distributor through
the
distribution outlet.
[0014] In another embodiment, a slurry distributor includes a feed conduit
and a
distribution conduit. The feed conduit includes an entry segment with a feed
inlet
and a feed entry outlet in fluid communication with the feed inlet. The entry
segment
extends along a first feed flow axis. The feed conduit includes a shaped duct
having
a bulb portion in fluid communication with the feed entry outlet of the entry
segment.
The feed conduit includes a transition segment in fluid communication with the
bulb
portion. The transition segment extends along a second feed flow axis, which
is in
non-parallel relationship with the first feed flow axis.
[0015] The distribution conduit extends generally along a longitudinal axis
and
includes an entry portion and a distribution outlet in fluid communication
with the
entry portion. The entry portion is in fluid communication with the feed inlet
of the
feed conduit. The distribution outlet extends a predetermined distance along a
transverse axis, which is substantially perpendicular to the longitudinal
axis.
[0016] The bulb portion has an area of expansion with a cross-sectional
flow area
that is greater than a cross-sectional flow area of an adjacent area upstream
from
the area of expansion relative to a flow direction from the feed inlet toward
the
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distribution outlet distribution conduit. The shaped duct has a convex
interior surface
in confronting relationship with the feed entry outlet of the entry segment.
[0017] In still another embodiment, a slurry distributor includes a
bifurcated feed
conduit and a distribution conduit. The bifurcated feed conduit includes a
first and a
second feed portion each having an entry segment with a feed inlet and a feed
entry
outlet in fluid communication with the feed inlet, a shaped duct having a bulb
portion
in fluid communication with the feed entry outlet of the entry segment, and a
transition segment in fluid communication with the bulb portion. The entry
segment
extends generally along a vertical axis. The transition segment extends along
a
longitudinal axis, which perpendicular to the vertical axis.
[0018] The distribution conduit extends generally along the longitudinal
axis and
includes an entry portion and a distribution outlet in fluid communication
with the
entry portion. The entry portion is in fluid communication with the first and
second
feed inlets of the feed conduit. The distribution outlet extends a
predetermined
distance along a transverse axis, which is substantially perpendicular to the
longitudinal axis.
[0019] The first and second bulb portions each has an area of expansion
with a
cross-sectional flow area that is greater than a cross-sectional flow area of
an
adjacent area upstream from the area of expansion relative to a flow direction
from
the respective first and second feed inlets toward the distribution outlet
distribution
conduit. The first and second shaped ducts each has a convex interior surface
in
confronting relationship with the respective first and second feed entry
outlets of the
first and second entry segments.
[0020] In another embodiment, a slurry distributor includes a distribution
conduit
and a slurry wiping mechanism. The distribution conduit extends generally
along a
longitudinal axis, a distribution outlet in fluid communication with the entry
portion,
and a bottom surface extending between the entry portion and the distribution
outlet.
The distribution outlet extends a predetermined distance along a transverse
axis,
which is substantially perpendicular to the longitudinal axis. The slurry
wiping
mechanism includes a movable wiper blade in contacting relationship with the
bottom surface of the distribution conduit. The wiper blade is reciprocally
movable
over a clearing path between a first position and a second position. The
clearing
path is disposed adjacent the distribution outlet.
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100211 In still another embodiment, a slurry distributor includes a
distribution
conduit and a profiling mechanism. The distribution conduit extends generally
along
a longitudinal axis and includes an entry portion and a distribution outlet in
fluid
communication with the entry portion. The distribution outlet extends a
predetermined distance along a transverse axis, which is substantially
perpendicular
to the longitudinal axis. The distribution outlet includes an outlet opening
having a
width, along the transverse axis, and a height, along a vertical axis mutually
perpendicular to the longitudinal axis and the transverse axis.
[0022] The profiling mechanism includes a profiling member in contacting
relationship with the distribution conduit. The profiling member is movable
over a
range of travel such that the profiling member is in a range of positions over
which
the profiling member is in increasing compressive engagement with a portion of
the
distribution conduit adjacent the distribution outlet to vary the shape and/or
size of
the outlet opening.
[0023] In another aspect of the present disclosure, the slurry distributor
can be
used in a cementitious slurry mixing and dispensing assembly. For example, a
slurry
distributor can be used to distribute an aqueous calcined gypsum slurry upon
an
advancing web. In other embodiments, a gypsum slurry mixing and dispensing
assembly includes a mixer and a slurry distributor in fluid communication with
the
mixer. The mixer is adapted to agitate water and calcined gypsum to form an
aqueous calcined gypsum slurry. The slurry distributor includes a feed conduit
and a
distribution conduit:
[0024] The feed conduit includes a first entry segment with a first feed
inlet and a
second entry segment with a second feed inlet disposed in spaced relationship
to the
first feed inlet. The first feed inlet is adapted to receive a first flow of
aqueous
calcined gypsum slurry from the gypsum slurry mixer. The second feed inlet is
adapted to receive a second flow of aqueous calcined gypsum slurry from the
gypsum slurry mixer.
[0025] The distribution conduit extends generally along a longitudinal axis
and
includes an entry portion and a distribution outlet in fluid communication
with the
entry portion. The entry portion is in fluid communication with the first and
second
feed inlets of the feed conduit. The distribution outlet extends a
predetermined
distance along a transverse axis. The transverse axis is substantially
perpendicular
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to the longitudinal axis. The distribution outlet is in fluid communication
with both the
first and the second feed inlets and is adapted such that the first and second
flows of
aqueous calcined gypsum slurry discharge from the slurry distributor through
the
distribution outlet.
[0026] The first and second feed inlets each has an opening with a cross-
sectional area. The entry portion of the distribution conduit has an opening
with a
cross-sectional area which is greater than the sum of the cross-sectional
areas of the
openings of the first and second feed inlets.
[0027] A cementitious slurry mixing and dispensing assembly including a
mixer
adapted to agitate water and a cementitious material to form an aqueous
cementitious slurry and a slurry distributor in fluid communication with the
mixer.
The slurry distributor can be any one of the various embodiments of a slurry
distributor following principles of the present disclosure.
[0028] In still another aspect of the present disclosure, the slurry
distribution
system can be used in a method of preparing a cementitious product. For
example,
a slurry distributor can be used to distribute an aqueous calcined gypsum
slurry upon
an advancing web.
[0029] In some embodiments, a method of distributing an aqueous calcined
gypsum slurry upon a moving web can be performed using a slurry distributor
constructed according to principles of the present disclosure. A first flow of
aqueous
calcined gypsum slurry and a second flow of aqueous calcined gypsum slurry are
respectively passed through a first feed inlet and a second feed inlet of the
slurry
distributor. The first and second flows of aqueous calcined gypsum slurry are
combined in the slurry distributor. The first and second flows of aqueous
calcined
gypsum slurry are discharged from a distribution outlet of the slurry
distributor upon
the moving web.
[0030] In other embodiments, a method of preparing a gypsum product can be
performed using a slurry distributor constructed according to principles of
the present
disclosure. A first flow of aqueous calcined gypsum slurry is passed at an
average
first feed velocity through a first feed inlet of a slurry distributor. A
second flow of
aqueous calcined gypsum slurry is passed at an average second feed velocity
through a second feed inlet of the slurry distributor. The second feed inlet
is in
spaced relationship to the first feed inlet. The first and second flows of
aqueous
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calcined gypsum slurry are combined in the slurry distributor. The combined
first
and second flows of aqueous calcined gypsum slurry are discharged at an
average
discharge velocity from a distribution outlet of the slurry distributor upon a
web of
cover sheet material moving along a machine direction. The average discharge
velocity is less than the average first feed velocity and the average second
feed
velocity.
[0031] In another embodiment, a method of preparing a cementitious product
can
be performed using a slurry distributor constructed according to principles of
the
present disclosure. A flow of aqueous cementitious slurry is discharged from a
mixer. A flow of aqueous cementitious slurry is passed at an average feed
velocity
through a feed inlet of a slurry distributor along a first feed flow axis. The
flow of
aqueous cementitious slurry is passed into a bulb portion of the slurry
distributor.
The bulb portion has an area of expansion with a cross-sectional flow area
that is
greater than a cross-sectional flow area of an adjacent area upstream from the
area
of expansion relative to a flow direction from the feed inlet. The bulb
portion is
configured to reduce the average velocity of the flow of aqueous cementitious
slurry
moving from the feed inlet through the bulb portion. The shaped duct has a
convex
interior surface in confronting relationship with first feed flow axis such
that the flow
of aqueous cementitious slurry moves in radial flow in a plane substantially
perpendicular to the first feed flow axis The flow of aqueous cementitious
slurry is
passed into a transition segment extending along a second feed flow axis,
which is in
non-parallel relationship with the first feed flow axis. The flow of aqueous
cementitious slurry is passed into a distribution conduit. The distribution
conduit
includes a distribution outlet extending a predetermined distance along a
transverse
axis, which is substantially perpendicular to the longitudinal axis.
[0032] In another embodiment, a method of preparing a cementitious product
includes discharging a flow of aqueous cementitious slurry from a mixer. The
flow of
aqueous cementitious slurry is passed through an entry portion of a
distribution
conduit of a slurry distributor. The flow of aqueous cementitious slurry is
discharged
from a distribution outlet of the slurry distributor upon a web of cover sheet
material
moving along a machine direction. A wiper blade is reciprocally moved over a
clearing path along a bottom surface of the distribution conduit between a
first
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position and a second position to clear aqueous cementitious slurry therefrom.
The
clearing path is disposed adjacent the distribution outlet.
[0033] In still another embodiment, a method of preparing a cementitious
product
includes discharging a flow of aqueous cementitious slurry from a mixer. The
flow of
aqueous cementitious slurry is passed through an entry portion of a
distribution
conduit of a slurry distributor. The flow of aqueous cementitious slurry is
discharged
from an outlet opening of a distribution outlet of the slurry distributor upon
a web of
cover sheet material moving along a machine direction. The distribution outlet
extends a predetermined distance along a transverse axis, which is
substantially
perpendicular to the longitudinal axis. The outlet opening has a width, along
the
transverse axis, and a height, along a vertical axis mutually perpendicular to
the
longitudinal axis and the transverse axis. A portion of the distribution
conduit
adjacent the distribution outlet is compressively engaged to vary the shape
and/or
size of the outlet opening.
[0034] Embodiments of a mold for use in a method for making a slurry
distributor
according to principles of the present disclosure are also disclosed herein.
Embodiments of supports for a slurry distributor according to principles of
the
present disclosure are also disclosed herein.
[0035] Further and alternative aspects and features of the disclosed
principles will
be appreciated from the following detailed description and the accompanying
drawings. As will be appreciated, the slurry distribution systems disclosed
herein are
capable of being carried out and used in other and different embodiments, and
capable of being modified in various respects. Accordingly, it is to be
understood
that both the foregoing general description and the following detailed
description are
exemplary and explanatory only and do not restrict the scope of the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The patent or application file contains at least one drawing
executed in
color. Copies of this patent or patent application publication with color
drawing(s) will
be provided by the Office upon request and payment of the necessary fee.
[0037] FIG. I is a perspective view of an embodiment of a slurry
distributor
constructed in accordance with principles of the present disclosure.
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[0038] FIG. 2 is a perspective view of the slurry distributor of FIG. 1 and
a
perspective view of an embodiment of a slurry distributor support constructed
in
accordance with principles of the present disclosure.
[0039] FIG. 3 is a front elevational view of the slurry distributor of FIG.
1 and the
slurry distributor support of FIG. 2.
[0040] FIG. 4 is a perspective view of an embodiment of a slurry
distributor
constructed in accordance with principles of the present disclosure that
defines an
interior geometry that is similar to the slurry distributor of FIG. 1, but
that is
constructed from a rigid material and has a two-piece construction.
[0041] FIG. 5 is another perspective view of the slurry distributor of FIG.
4 but
with a profiling system removed for illustrative purposes.
[0042] FIG. 6 is an isometric view of another embodiment of a slurry
distributor
constructed in accordance with principles of the present disclosure, which
includes a
first feed inlet and a second feed inlet disposed at about a sixty degree feed
angle
with respect to a longitudinal axis or machine direction of the slurry
distributor.
[0043] FIG. 7 is a top plan view of the slurry distributor of FIG. 6.
[0044] FIG. 8 is a rear elevational view of the slurry distributor of FIG.
6.
[0045] FIG. 9 is a top plan view of a first piece of the slurry distributor
of FIG. 6,
which has a two-piece construction.
[0046] FIG. 10 is a front perspective view of the slurry distributor piece
of FIG. 9.
[0047] FIG. 11 is an exploded view of the slurry distributor of FIG. 6 and
a support
system for the slurry distributor constructed in accordance with principles of
the
present disclosure.
[0048] FIG. 12 is a perspective view of the slurry distributor and the
support
system of FIG. 11.
[0049] FIG. 13 is an exploded view of the slurry distributor of FIG. 6 and
another
embodiment of a support system constructed in accordance with principles of
the
present disclosure.
[0050] FIG. 14 is a perspective view of the slurry distributor and the
support
system of FIG. 13.
[0051] FIG. 15 is a perspective view of an embodiment of a slurry
distributor
constructed in accordance with principles of the present disclosure that
defines an
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interior geometry that is similar to the slurry distributor of FIG. 6, but
that is
constructed from a flexible material and has an integral construction.
[0052] FIG. 16 is a top plan view of the slurry distributor of FIG. 15.
[0053] FIG. 17 is an enlarged, perspective view of the interior geometry
defined
by the slurry distributor of FIG. 15, illustrating progressive cross-sectional
flow areas
of a portion of the feed conduit thereof.
[0054] FIG. 18 is an enlarged, perspective view of the interior geometry of
the
slurry distributor of FIG. 15, illustrating another progressive cross-
sectional flow area
of the feed conduit.
[0055] FIG. 19 is an enlarged, perspective view of the interior geometry of
the
slurry distributor of FIG. 15, illustrating yet another progressive cross-
sectional flow
area of the feed conduit which is aligned with a half of an entry portion to a
distribution conduit of the slurry distributor of FIG. 15.
[0056] FIG. 20 is a perspective view of the slurry distributor of FIG. 15
and
another embodiment of a support system constructed in accordance with
principles
of the present disclosure.
[0057] FIG. 21 is a perspective view as in FIG. 20, but with a support
frame
removed for illustrative purposes to show a plurality of retaining plates in
distributed
relationship with the slurry distributor of FIG. 15.
[0058] FIG. 22 is a front perspective view of another embodiment of a
slurry
distributor and another embodiment of a support system constructed in
accordance
with principles of the present disclosure.
[0059] FIG. 23 is a rear perspective view of the slurry distributor and the
support
system of FIG. 22.
[0060] FIG. 24 is a top plan view of the slurry distributor and the support
system
of FIG. 22.
[0061] FIG. 25 is a side elevational view of the slurry distributor and the
support
system of FIG. 22.
[0062] FIG. 26 is a front elevational view of the slurry distributor and
the support
system of FIG. 22.
[0063] FIG. 27 is a rear elevational view of the slurry distributor and the
support
system of FIG. 22.
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[0064] FIG. 28 is an enlarged, detail view of a distal portion of the
slurry
distributor, illustrating an embodiment of a slurry wiping mechanism
constructed in
accordance with principles of the present disclosure.
[0065] FIG. 29 is a perspective view of a profiling mechanism constructed
in
accordance with principles of the present disclosure and used in the slurry
distributor
of FIG. 22.
[0066] FIG. 30 is a front elevational view of the profiling mechanism of
FIG. 29.
[0067] FIG. 30A is a view as in FIG. 30, illustrating a profiling member of
the
profiling mechanism in a compressed position.
[0068] FIG. 30B is a view as in FIG. 30, illustrating the profiling member
of the
profiling mechanism in a pivoted position.
[0069] FIG. 30C is an enlarged, detail exploded view of the profiling
member,
illustrating a connection technique between a translation rod and a profiling
segment.
[0070] FIG. 31 is a side elevational view of the profiling mechanism of
FIG. 29.
[0071] FIG. 32 is a top plan view of the profiling mechanism of FIG. 29.
[0072] FIG. 33 is a bottom elevational view of the profiling mechanism of
FIG. 29.
[0073] FIG. 34 is a top plan view of the slurry distributor and the support
system
of FIG. 22 with a support frame removed for illustrative purposes.
[0074] FIG. 35 is an enlarged, detail view taken from the side of a bulb
portion of
the slurry distributor of FIG. 22.
[0075] FIG. 36 is a perspective view of a pair of rigid support inserts
resting upon
a bottom support member of the support system of FIG. 22.
[0076] FIG. 37 is a side elevational view of the rigid support insert of
FIG. 36.
[0077] FIG. 38 is a front elevational view of the rigid support insert of
FIG. 36.
[0078] FIG. 39 is a rear elevational view of the rigid support insert of
FIG. 36.
[0079] FIG. 40 is a front elevational view of the slurry distributor of
FIG. 22.
[0080] FIG. 41 is a rear elevational view of the slurry distributor of FIG.
22.
[0081] FIG. 42 is a bottom perspective view of the slurry distributor of
FIG. 22.
[0082] FIG. 43 is a bottom plan view of the slurry distributor of FIG. 22.
[0083] FIG. 44 is a top plan view of a half portion of the slurry
distributor of FIG.
22.
[0084] FIG. 45 is a cross-sectional view taken along line 45-45 in FIG. 44.
[0085] FIG. 46 is a cross-sectional view taken along line 46-46 in FIG. 44.
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[0086] FIG. 47 is a cross-sectional view taken along line 47-47 in FIG. 44.
[0087] FIG. 48 is a cross-sectional view taken along line 48-48 in FIG. 44.
[0088] FIG. 49 is a cross-sectional view taken along line 49-49 in FIG. 44.
[0089] FIG. 50 is a cross-sectional view taken along line 50-50 in FIG. 44.
[0090] FIG. 51 is a cross-sectional view taken along line 51-51 in FIG. 44.
[0091] FIG. 52 is a cross-sectional view taken along line 52-52 in FIG. 44.
[0092] FIG. 53 is a cross-sectional view taken along line 53-53 in FIG. 44.
[0093] FIG. 54 is a perspective view of an embodiment of a multi-piece mold
for
making a slurry distributor as in FIG. 1 constructed in accordance with
principles of
the present disclosure.
[0094] FIG. 55 is a top plan view of the mold of FIG. 54.
[0095] FIG. 56 is an exploded view of an embodiment of a multi-piece mold
for
making a slurry distributor as in FIG. 15 constructed in accordance with
principles of
the present disclosure.
[0096] FIG. 57 is a perspective view of another embodiment of a mold for
making
a piece of a two-piece slurry distributor constructed in accordance with
principles of
the present disclosure.
[0097] FIG. 58 is a top plan view of the mold of FIG. 57.
[0098] FIG. 59 is a schematic plan diagram of an embodiment of a gypsum
slurry
mixing and dispensing assembly including a slurry distributor in accordance
with
principles of the present disclosure.
[0099] FIG. 60 is a schematic plan diagram of another embodiment of a
gypsum
slurry mixing and dispensing assembly including a slurry distributor in
accordance
with principles of the present disclosure.
[00100] FIG. 61 is a schematic elevational diagram of an embodiment of a wet
end
of a gypsum wallboard manufacturing line in accordance with principles of the
present disclosure.
[00101] FIG .62 is a perspective view of an embodiment of a flow splitter
constructed in accordance with principles of the present disclosure suitable
for use in
a gypsum slurry mixing and dispensing assembly including a slurry distributor.
[00102] FIG. 63 is a side elevational view, in section, of the flow
splitter of FIG. 62.
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[00103] FIG. 64 is a side elevational view of the flow splitter of FIG. 62
with an
embodiment of a squeezing apparatus constructed in accordance with principles
of
the present disclosure mounted thereto.
[00104] FIG. 65 is a top plan view of a half portion of a slurry
distributor similar to
the slurry distributor of FIG. 15.
[00105] FIG. 66 is a plot of the data from Table I of Example 1 showing the
dimensionless distance from the feed inlet versus the dimensionless area and
the
dimensionless hydraulic radius of the half portion of the slurry distributor
of FIG. 65.
[00106] FIG. 67 is a plot of the data from Tables II and III of Examples 2 and
3,
respectively, showing the dimensionless distance from the feed inlet versus
the
dimensionless velocity of a flow of modeled slurry moving through the half
portion of
the slurry distributor of FIG. 65.
[00107] FIG. 68 is a plot of the data from Tables II and III of Examples 2 and
3,
respectively, showing the dimensionless distance from the feed inlet versus
the
dimensionless shear rate in the modeled slurry moving through the half portion
of the
slurry distributor of FIG. 65.
[00108] FIG. 69 is a plot of the data from Tables II and III of Examples 2
and 3,
respectively, showing the dimensionless distance from the feed inlet versus
the
dimensionless viscosity of the modeled slurry moving through the half portion
of the
slurry distributor of FIG. 65.
[00109] FIG. 70 is a plot of the data from Tables II and III of Examples 2
and 3,
respectively, showing the dimensionless distance from the feed inlet versus
the
dimensionless shear stress in the modeled slurry moving through the half
portion of
the slurry distributor of FIG. 65.
[00110] FIG. 71 is a plot of the data from Tables II and III of Examples 2
and 3,
respectively, showing the dimensionless distance from the feed inlet versus
the
dimensionless Reynolds number of the modeled slurry moving through the half
portion of the slurry distributor of FIG. 65.
[00111] FIG. 72 is a top plan view of a slurry distributor similar to the
slurry
distributor of FIG. 22.
[00112] FIG. 73 is a top perspective view of a computational fluid dynamics
(CFD)
model output for a half portion of the slurry distributor of FIG. 72.
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[00113] FIG. 74 is a view as in FIG. 73, illustrating various regions
discussed in
Examples 4-6.
[00114] FIG. 75 is a view of the region A indicated in FIG. 74.
[00115] FIG. 76 is a top plan view of the region A illustrating radial
locations used
to conduct CFD analysis.
[00116] FIG. 77 is a plot of the data from Table IV of Example 4 showing the
radial
location at region A versus the dimensionless average velocity moving through
region A of the half portion of the slurry distributor of FIG. 73.
[00117] FIG. 78 is an enlarged, detail view taken from FIG. 72,
illustrating a region
B of the slurry distributor in which a flow of slurry moving therethrough has
a swirl
motion.
[00118] FIG. 79 is a plot of the data from Table VI of Example 6 showing the
dimensionless distance from the feed inlet versus the dimensionless velocity
of a
flow of modeled slurry moving through the half portion of the slurry
distributor of FIG.
73.
[00119] FIG. 80 is a plot of the data from Table VI of Example 6 showing the
dimensionless distance from the feed inlet versus the dimensionless shear rate
in
the modeled slurry moving through the half portion of the slurry distributor
of FIG. 73.
[00120] FIG. 81 is a plot of the data from Table VI of Example 6 showing the
dimensionless distance from the feed inlet versus the dimensionless viscosity
of the
modeled slurry moving through the half portion of the slurry distributor of
FIG. 73.
[00121] FIG. 82 is a plot of the data from Table VI of Example 6 showing the
dimensionless distance from the feed inlet versus the dimensionless Reynolds
number of the modeled slurry moving through the half portion of the slurry
distributor
of FIG. 73.
[00122] FIG. 83 is a plot of the data from Table VII of Example 7 showing the
dimensionless distance along the width of the outlet opening from a central
transverse midpoint versus the spread angle of the modeled slurry discharging
from
the half portion of the slurry distributor of FIG. 73.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[00123] The present disclosure provides various embodiments of a slurry
distribution system that can be used in the manufacture of products, including
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cementitious products such as gypsum wallboard, for example. Embodiments of a
slurry distributor constructed in accordance with principles of the present
disclosure
can be used in a manufacturing process to effectively distribute a multi-phase
slurry,
such as one containing air and liquid phases, such as found in an aqueous
foamed
gypsum slurry, for example.
[00124] Embodiments of a distribution system constructed in accordance with
principles of the present disclosure can be used to distribute a slurry (e.g.,
an
aqueous calcined gypsum slurry) onto an advancing web (e.g., paper or mat)
moving
on a conveyor during a continuous board (e.g., wallboard) manufacturing
process.
In one aspect, a slurry distribution system constructed in accordance with
principles
of the present disclosure can be used in a conventional gypsum drywall
manufacturing process as, or part of, a discharge conduit attached to a mixer
adapted to agitate calcined gypsum and water to form an aqueous calcined
gypsum
slurry.
[00125] Embodiments of a slurry distribution system constructed in accordance
with principles of the present disclosure are aimed at accomplishing wider
distribution (along the cross-machine direction) of a uniform gypsum slurry.
Embodiments of a slurry distribution system of the present disclosure are
suitable for
use with a gypsum slurry having a range of WSRs, including WSRs conventionally
used to manufacture gypsum wallboard and those that are relatively lower and
have
a relatively higher viscosity. Furthermore, a gypsum slurry distribution
system of the
present disclosure can be used to help control air-liquid phase separation,
such as,
in aqueous foamed gypsum slurry, including foamed gypsum slurry having a very
high foam volume. The spreading of the aqueous calcined gypsum slurry over the
advancing web can be controlled by routing and distributing the slurry using a
distribution system as shown and described herein.
[00126] A cementitious slurry mixing and dispensing assembly according to
principles of the present disclosure can be used to form any type of
cementitious
product, such as a board, for example. In some embodiments, a cementitious
board,
such as a gypsum drywall, a Portland cement board or an acoustical panel, for
example, can be formed.
[00127] The cementitious slurry can be any conventional cementitious slurry,
for
example any cementitious slurry commonly used to produce gypsum wallboard,
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acoustical panels including, for example, acoustical panels described in U.S.
Patent
Application Publication No. 2004/0231916, or Portland cement board. As such,
the
cementitious slurry can optionally further comprise any additives commonly
used to
produce cementitious board products. Such additives include structural
additives
including mineral wool, continuous or chopped glass fibers (also referred to
as
fiberglass), perlite, clay, vermiculite, calcium carbonate, polyester, and
paper fiber,
as well as chemical additives such as foaming agents, fillers, accelerators,
sugar,
enhancing agents such as phosphates, phosphonates, borates and the like,
retarders, binders (e.g., starch and latex), colorants, fungicides, biocides,
hydrophobic agent, such as a silicone-based material (e.g., a silane,
siloxane, or
silicone-resin matrix), and the like. Examples of the use of some of these and
other
additives are described, for instance, in U.S. Patent Nos. 6,342,284;
6,632,550;
6,800,131; 5,643,510; 5,714,001; and 6,774,146; and U.S. Patent Application
Publication Nos. 2004/0231916; 2002/0045074; 2005/0019618; 2006/0035112; and
2007/0022913.
[00128] Non-
limiting examples of cementitious materials include Portland cement,
sorrel cement, slag cement, fly ash cement, calcium alumina cement, water-
soluble
calcium sulfate anhydrite, calcium sulfate a-hemihydrate, calcium sulfate 3-
hemihydrate, natural, synthetic or chemically modified calcium sulfate
hemihydrate,
calcium sulfate dihydrate ("gypsum," "set gypsum," or "hydrated gypsum"), and
mixtures thereof. In one aspect, the cementitious material desirably comprises
calcined gypsum, such as in the form of calcium sulfate alpha hemihydrate,
calcium
sulfate beta hemihydrate, and/or calcium sulfate anhydrite. In embodiments,
the
calcined gypsum can be fibrous in some embodiments and nonfibrous in others.
The calcined gypsum can include at least about 50% beta calcium sulfate
hemihydrate. In other embodiments, the calcined gypsum can include at least
about
86% beta calcium sulfate hemihydrate. The weight ratio of water to calcined
gypsum
can be any suitable ratio, although, as one of ordinary skill in the art will
appreciate,
lower ratios can be more efficient because less excess water must be driven
off
during manufacture, thereby conserving energy. In some embodiments, the
cementitious slurry can be prepared by combining water and calcined gypsum in
a
range from about a 1:6 ratio by weight respectively to about 1:1 ratio, such
as about
2:3, for board production depending on products.
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[00129] Embodiments of a method of preparing a cementitious product, such as a
gypsum product, in accordance with principles of the present disclosure can
include
distributing an aqueous calcined gypsum slurry upon an advancing web using a
slurry distributor constructed in accordance with principles of the present
disclosure.
Various embodiments of a method of distributing an aqueous calcined gypsum
slurry
upon a moving web are described herein.
[00130] Turning now to the Figures, there is shown in FIGS. 1-3 an embodiment
of
a slurry distributor 120 according to principles of the present disclosure,
and in FIGS.
4 and 5, another embodiment of a slurry distributor 220 according to
principles of the
present disclosure is shown. The slurry distributor 120 shown in FIGS. 1-3 is
constructed from a resiliently flexible material, whereas the slurry
distributor 220
shown in FIGS. 3 and 4 is made from a relatively rigid material. However, the
interior flow geometry of both slurry distributors 120, 220 in FIGS. 1-5 is
the same,
and reference should also be made to FIG. 5 when considering the slurry
distributor
120 of FIGS. 1-3.
[00131] Referring to FIG. 1, the slurry distributor 120 includes a feed
conduit 122,
which has first and second feed inlets 124, 125, and a distribution conduit
128, which
includes a distribution outlet 130 and is in fluid communication with the feed
conduit
128. A profiling system 132 (see FIG. 3) adapted to locally vary the size of
the
distribution outlet 130 of the distribution conduit 128 can also be provided.
[00132] Referring to FIG. 1, the feed conduit 122 extends generally along a
transverse axis or cross-machine direction 60, which is substantially
perpendicular to
a longitudinal axis or machine direction 50. The first feed inlet 124 is in
spaced
relationship with the second feed inlet 125. The first feed inlet 124 and the
second
feed inlet 125 define respective openings 134, 135 that have substantially the
same
area. The illustrated openings 134, 135 of the first and second feed inlets
124, 125
both have a circular cross-sectional shape as illustrated in this example. In
other
embodiments, the cross-sectional shape of the feed inlets 124, 125 can take
other
forms, depending upon the intended applications and process conditions
present.
[00133] The first and second feed inlets 124, 125 are in opposing relationship
to
each other along the cross-machine axis 60 such that the first and second feed
inlets
124, 125 are disposed at substantially a 90 angle to the machine axis 50. In
other
embodiments the first and second feed inlets 124, 125 can be oriented in a
different
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manner with respect to the machine direction. For example, in some
embodiments,
the first and second feed inlets 124, 125 can be at an angle between 0 and
about
135 with respect to the machine direction 50.
[00134] The feed conduit 122 includes first and second entry segments 136, 137
and a bifurcated connector segment 139 disposed between the first and second
entry segments 136, 137. The first and second entry segments 136, 137 are
generally cylindrical and extend along the transverse axis 60 such that they
are
substantially parallel to a plane 57 defined by the longitudinal axis 50 and
the
transverse axis 60. The first and second feed inlets 124, 125 are disposed at
the
distal ends of the first and the second entry segments 136, 137, respectively,
and
are in fluid communication therewith.
[00135] In other embodiments the first and second feed inlets 124, 125 and the
first and second entry segments 136, 137 can be oriented in a different manner
with
respect to the transverse axis 60, the machine direction 50, and/or the plane
57
defined by the longitudinal axis 50 and the transverse axis 60. For example,
in some
embodiments, the first and second feed inlets 124, 125 and the first and
second
entry segments 136, 137 can each be disposed substantially in the plane 57
defined
by the longitudinal axis 50 and the transverse axis 60 at a feed angle U with
respect
to the longitudinal axis or machine direction 50 which is an angle in a range
up to
about 135 with respect to the machine direction 50, and in other embodiments
in a
range from about 30 to about 1350, and in yet other embodiments in a range
from
about 45 to about 1350, and in still other embodiments in a range from about
40 to
about 110 .
[00136] The bifurcated connector segment 139 is in fluid communication with
the
first and second feed inlets 124, 125 and the first and the second entry
segments
136, 137. The bifurcated connector segment 139 includes first and second
shaped
ducts 141, 143. The first and second feed inlets 124, 125 of the feed conduit
22 are
in fluid communication with the first and second shaped ducts 141, 143,
respectively.
The first and second shaped ducts 141, 143 of the connector segment 139 are
adapted to receive a first flow in a first feed direction 190 and a second
flow in a
second flow direction 191 of aqueous calcined gypsum slurry from the first and
second feed inlets 124, 125, respectively, and to direct the first and second
flows
190, 191 of aqueous calcined gypsum slurry into the distribution conduit 128.
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[00137] As shown in FIG. 5, the first and second shaped ducts 141, 143 of the
connector segment 139 define first and second feed outlets 140, 145
respectively in
fluid communication with the first and second feed inlets 124, 125. Each feed
outlet
140, 145 is in fluid communication with the distribution conduit 128. Each of
the
illustrated first and second feed outlets 140, 145 defines an opening 142 with
a
generally rectangular inner portion 147 and a substantially circular side
portion 149.
The circular side portions 145 are disposed adjacent side walls 151, 153 of
the
distribution conduit 128.
[00138] In embodiments, the openings 142 of the first and second feed outlets
140, 145 can have a cross-sectional area that is larger than the cross-
sectional area
of the openings 134, 135 of the first feed inlet 124 and the second feed inlet
125,
respectively. For example, in some embodiments, the cross-sectional area of
the
openings 142 of the first and second feed outlets 140, 145 can be in a range
from
greater than to about 300% greater than the cross-sectional area of the
openings
134, 135 of the first feed inlet 124 and the second feed inlet 125,
respectively, in a
range from greater than to about 200% greater in other embodiments, and in a
range
from greater than to about 150% greater in still other embodiments.
[00139] In embodiments, the openings 142 of the first and second feed outlets
140, 145 can have a hydraulic diameter (4 x cross-sectional area / perimeter)
that is
smaller than the hydraulic diameter of the openings 134, 135 of the first feed
inlet
124 and the second feed inlet 125, respectively. For example, in some
embodiments, the hydraulic diameter of the openings 142 of the first and
second
feed outlets 140, 145 can be about 80% or less than the hydraulic diameter of
the
openings 134, 135 of the first feed inlet 124 and the second feed inlet 125,
respectively, about 70% or less in other embodiments, and about 50% or less in
still
other embodiments
[00140] Referring back to FIG. 1, the connector segment 139 is
substantially
parallel to the plane 57 defined by the longitudinal axis 50 and the
transverse axis
60. In other embodiments the connector segment 139 can be oriented in a
different
manner with respect to the transverse axis 60, the machine direction 50,
and/or the
plane 57 defined by the longitudinal axis 50 and the transverse axis 60.
[00141] The first feed inlet 124, the first entry segment 136, and the first
shaped
duct 141 are a mirror image of the second feed inlet 125, the second entry
segment
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137, and the second shaped duct 143, respectively. Accordingly, it will be
understood that the description of one feed inlet is applicable to the other
feed inlet,
the description of one entry segment is applicable to the other entry segment,
and
the description of one shaped duct is applicable to the other shaped duct, as
well in
a corresponding manner.
[00142] The first shaped duct 141 is fluidly connected to the first feed inlet
124 and
the first entry segment 136. The first shaped duct 141 is also fluidly
connected to the
distribution conduit 128 to thereby help fluidly connect the first feed inlet
124 and the
distribution outlet 130 such that the first flow 190 of slurry can enter the
first feed inlet
124; travel through the first entry segment 136, the first shaped duct 141,
and the
distribution conduit 128; and be discharged from the slurry distributor 120
through
the distribution outlet 130.
[00143] The first shaped duct 141 has a front, outer curved wall 157 and an
opposing rear, inner curved wall 158 defining a curved guide surface 165
adapted to
redirect the first flow of slurry from the first feed flow direction 190,
which is
substantially parallel to the transverse or cross-machine direction 60, to an
outlet
flow direction 192, which is substantially parallel to the longitudinal axis
or machine
direction 50 and substantially perpendicular to the first feed flow direction
190. The
first shaped duct 141 is adapted to receive the first flow of slurry moving in
the first
feed flow direction 190 and redirect the slurry flow direction by a change in
direction
angle a, as shown in FIG. 9, such that the first flow of slurry is conveyed
into the
distribution conduit 128 moving substantially in the outlet flow direction
192.
[00144] In use, the first flow of aqueous calcined gypsum slurry passes
through the
first feed inlet 124 in the first feed direction 190, and the second flow of
aqueous
calcined gypsum slurry passes through the second feed inlet 125 in the second
feed
direction 191. The first and second feed directions 190, 191 can be
symmetrical with
respect to each other along the longitudinal axis 50 in some embodiments. The
first
flow of slurry moving in the first feed flow direction 190 is redirected in
the slurry
distributor 120 through a change in direction angle a in a range up to about
135 to
the outlet flow direction 192. The second flow of slurry moving in the second
feed
flow direction 191 is redirected in the slurry distributor 120 through a
change in
direction angle a in a range up to about 135 to the outlet flow direction
192. The
combined first and second flows 190, 191 of aqueous calcined gypsum slurry
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discharge from the slurry distributor 120 moving generally in the outlet flow
direction
192. The outlet flow direction 192 can be substantially parallel to the
longitudinal
axis or machine direction 50.
[00145] For example, in the illustrated embodiment, the first flow of
slurry is
redirected from the first feed flow direction 190 along the cross-machine
direction 60
through a change in direction angle a of about ninety degrees about the
vertical axis
55 to the outlet flow direction 192 along the machine direction 50. In some
embodiments, the flow of slurry can be redirected from a first feed flow
direction 190
through a change in direction angle a about the vertical axis 55 which is in a
range
up to about 135 to the outlet flow direction 192, and in other embodiments in
a
range from about 30 to about 1350, and in yet other embodiments in a range
from
about 45 to about 1350, and in still other embodiments in a range from about
40 to
about 1100
.
[00146] In some embodiments, the shape of the rear curved guide surface 165
can
be generally parabolic, which in the illustrated embodiment can be defined by
a
parabola of the form Ax2+B. In alternate embodiments, higher order curves may
be
used to define the rear curved guide surface 165 or, alternatively, the rear,
inner wall
158 can have a generally curved shape that is made up of straight or linear
segments that have been oriented at their ends to collectively define a
generally
curved wall. Moreover, the parameters used to define the specific shape
factors of
the outer wall can depend on specific operating parameters of the process in
which
the slurry distributor will be used.
[00147] At least one of the feed conduit 122 and the distribution conduit 128
can
include an area of expansion having a cross-sectional flow area that is
greater than a
cross-sectional flow area of an adjacent area upstream from the area of
expansion in
a direction from the feed conduit 122 toward the distribution conduit 128. The
first
entry segment 136 and/or the first shaped duct 141 can have a cross section
that
varies along the direction of flow to help distribute the first flow of slurry
moving
therethrough. The shaped duct 141 can have a cross sectional flow area that
increases in a first flow direction 195 from the first feed inlet 124 toward
the
distribution conduit 128 such that the first flow of slurry is decelerated as
it passes
through the first shaped duct 141. In some embodiments, the first shaped duct
141
can have a maximum cross-section flow area at a predetermined point along the
first
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flow direction 195 and decrease from the maximum cross-sectional flow area at
points further along the first flow direction 195.
[00148] In some embodiments, the maximum cross-sectional flow area of the
first
shaped duct 141 is about 200% of the cross-sectional area of the opening 134
of the
first feed inlet 124 or less. In yet other embodiments, the maximum cross-
sectional
flow area of the shaped duct 141 is about 150% of the cross-sectional area of
the
opening 134 of the first feed inlet 124 or less. In still other embodiments,
the
maximum cross-sectional flow area of the shaped duct 141 is about 125% of the
cross-sectional area of the opening 134 of the first feed inlet 124 or less.
In yet other
embodiments, the maximum cross-sectional flow area of the shaped duct 141 is
about 110% of the cross-sectional area of the opening 134 of the first feed
inlet 124
or less. In some embodiments, the cross-sectional flow area is controlled such
that
the flow area does not vary more than a predetermined amount over a given
length
to help prevent large variations in the flow regime.
[00149] In some embodiments, the first entry segment 136 and/or the first
shaped
duct 141 can include one or more guide channels 167, 168 that are adapted to
help
distribute the first flow of slurry toward the outer and/or the inner walls
157, 158 of
the feed conduit 122. The guide channels 167, 168 are adapted to increase the
flow
of slurry around the boundary wall layers of the slurry distributor 120.
[00150] Referring to FIGS. 1 and 5, the guide channels 167, 168 can be
configured
to have a larger cross-sectional area than an adjacent portion 171 of the feed
conduit 122 which defines a restriction that promotes flow to the adjacent
guide
channel 167, 168 respectively disposed at the wall region of the slurry
distributor
120. In the illustrated embodiment, the feed conduit 122 includes the outer
guide
channel 167 adjacent the outer wall 157 and the sidewall 151 of the
distribution
conduit 128 and the inner guide channel 168 adjacent the inner wall 158 of the
first
shaped duct 141. The cross-sectional areas of the outer and inner guide
channels
167, 168 can become progressively smaller moving in the first flow direction
195.
The outer guide channel 167 can extend substantially along the sidewall 151 of
the
distribution conduit 128 to the distribution outlet 130. At a given cross-
sectional
location through the first shaped duct 141 in a direction perpendicular to the
first flow
direction 195, the outer guide channel 167 has a larger cross-sectional area
than the
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inner guide channel 168 to help divert the first flow of slurry from its
initial line of
movement in the first feed direction 190 toward the outer wall 157.
[00151] Providing guide channels adjacent wall regions can help direct or
guide
slurry flow to those regions, which can be areas in conventional systems where
"dead spots" of low slurry flow are found. By encouraging slurry flow at the
wall
regions of the slurry distributor 120 through the provision of guide channels,
slurry
buildup inside the slurry distributor is discouraged and the cleanliness of
the interior
of the slurry distributor 120 can be enhanced. The frequency of slurry buildup
breaking off into lumps which can tear the moving web of cover sheet material
can
also be decreased.
[00152] In other embodiments, the relative sizes of the outer and inner guide
channels 167, 168 can be varied to help adjust the slurry flow to improve flow
stability and reduce the occurrence of air-liquid slurry phase separation. For
example, in applications using a slurry that is relatively more viscous, at a
given
cross-sectional location through the first shaped duct 141 in a direction
perpendicular
to the first flow direction 195, the outer guide channel 167 can have a
smaller cross-
sectional area than the inner guide channel 168 to help urge the first flow of
slurry
toward the inner wall 158.
[00153] The inner curved walls 158 of the first and second shaped ducts 141,
142
meet to define a peak 175 adjacent an entry portion 152 of the distribution
conduit
128. The peak 175 effectively bifurcates the connector segment 139. Each feed
outlet 140, 145 is in fluid communication with the entry portion 152 of the
distribution
conduit 128.
[00154] The location of the peak 175 along the longitudinal axis 50 can vary
in
other embodiments. For example, the inner curved walls 158 of the first and
second
shaped ducts 141, 142 can be less curved in other embodiments such that the
peak
175 is further away from the distribution outlet 130 along the longitudinal
axis 50 than
as shown in the illustrated slurry distributor 120. In other embodiments, the
peak
175 can be closer to the distribution outlet 130 along the longitudinal axis
50 than as
shown in the illustrated slurry distributor 120.
[00155] The distribution conduit 128 is substantially parallel to the plane 57
defined
by the longitudinal axis 50 and the transverse axis 60 and is adapted to urge
the
combined first and second flows of aqueous calcined gypsum slurry from the
first
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and second shaped ducts 141, 142 into a generally two-dimensional flow pattern
for
enhanced stability and uniformity. The distribution outlet 130 has a width
that
extends a predetermined distance along the transverse axis 60 and a height
that
extends along a vertical axis 55, which is mutually perpendicular to the
longitudinal
axis 50 and the transverse axis 60. The height of the distribution outlet 130
is small
relative to its width. The distribution conduit 128 can be oriented relative
to a moving
web of cover sheet upon a forming table such that the distribution conduit 128
is
substantially parallel to the moving web.
[00156] The distribution conduit 128 extends generally along the longitudinal
axis
50 and includes the entry portion 152 and the distribution outlet 130. The
entry
portion 152 is in fluid communication with the first and second feed inlets
124, 125 of
the feed conduit 122. Referring to FIG. 5, the entry portion 152 is adapted to
receive
both the first and the second flows of aqueous calcined gypsum slurry from the
first
and second feed inlets 124, 125 of the feed conduit 122. The entry portion 152
of
the distribution conduit 128 includes a distribution inlet 154 in fluid
communication
with the first and second feed outlets 140, 145 of the feed conduit 122. The
illustrated distribution inlet 154 defines an opening 156 that substantially
corresponds to the openings 142 of the first and second feed outlets 140, 145.
The
first and second flows of aqueous calcined gypsum slurry combine in the
distribution
conduit 128 such that the combined flows move generally in the outlet flow
direction
192 which can be substantially aligned with the line of movement of a web of
cover
sheet material moving over a forming table in a wallboard manufacturing line.
[00157] The distribution outlet 130 is in fluid communication with the entry
portion
152 and thus the first and second feed inlets 124, 125 and the first and
second feed
outlets 140, 145 of the feed conduit 122. The distribution outlet 130 is in
fluid
communication with the first and second shaped ducts 141, 143 and is adapted
to
discharge the combined first and second flows of slurry therefrom along the
outlet
flow direction 192 upon a web of cover sheet material advancing along the
machine
direction 50.
[00158] Referring to FIG. 1, the illustrated distribution
outlet 130 defines a
generally rectangular opening 181 with semi-circular narrow ends 183, 185. The
semi-circular ends 183, 185 of the opening 181 of the distribution outlet 130
can be
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the terminating end of the outer guide channels 167 disposed adjacent the side
walls
151, 153 of the distribution conduit 128.
[00159] The opening 181 of the distribution outlet 130 has an area which is
greater
than the sum of the areas of the openings 134, 135 of the first and second
feed inlets
124, 125 and is smaller than the area of the sum of the openings 142 of the
first and
second feed outlets 140, 145 (i.e., the opening 156 of the distribution inlet
154).
Accordingly, the cross-sectional area of the opening 156 of the entry portion
152 of
the distribution conduit 128 is greater than the cross-sectional area of the
opening
181 of the distribution outlet 130.
[00160] For example, in some embodiments, the cross-sectional area of the
opening 181 of the distribution outlet 130 can be in a range from greater than
to
about 400% greater than the sum of the cross-sectional areas of the openings
134,
135 of the first and second feed inlets 124, 125, in a range from greater than
to
about 200% greater in other embodiments, and in a range from greater than to
about
150% greater in still other embodiments. In other embodiments, the ratio of
the sum
of the cross-sectional areas of the openings 134, 135 of the first and second
feed
inlets 124, 125 to the cross-sectional area of the opening 181 of the
distribution
outlet 130 can be varied based upon one or more factors, including the speed
of the
manufacturing line, the viscosity of the slurry being distributed by the
distributor 120,
the width of the board product being made with the distributor 120, etc. In
some
embodiments, the cross-sectional area of the opening 156 of the entry portion
152 of
the distribution conduit 128 can be in a range from greater than to about 200%
greater than the cross-sectional area of the opening 181 of the distribution
outlet
130, in a range from greater than to about 150% greater in other embodiments,
and
in a range from greater than to about 125% greater in still other embodiments.
[00161] The distribution outlet 130 extends substantially along the transverse
axis
60. The opening 181 of the distribution outlet 130 has a width W1 of about
twenty-
four inches along the transverse axis 60 and a height H1 of about one inch
along the
vertical axis 55 (see FIG. 3, also). In other embodiments, the size and shape
of the
opening 181 of the distribution outlet 130 can be varied.
[00162] The distribution outlet 130 is disposed intermediately along the
transverse
axis 60 between the first feed inlet 124 and the second feed inlet 125 such
that the
first feed inlet 124 and the second feed inlet 125 are disposed substantially
the same
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distance D1, D2 from a transverse central midpoint 187 of the distribution
outlet 130
(see FIG. 3, also). The distribution outlet 130 can be made from a resiliently
flexible
material such that its shape is adapted to be variable along the transverse
axis 60,
such as by the profiling system 32, for example.
[00163] It is contemplated that the width W1 and/or height H1 of the opening
181 of
the distribution outlet 130 can be varied in other embodiments for different
operating
conditions. In general, the overall dimensions of the various embodiments for
slurry
distributors as disclosed herein can be scaled up or down depending on the
type of
product being manufactured (for example, the thickness and/or width of
manufactured product), the speed of the manufacturing line being used, the
rate of
deposition of the slurry through the distributor, the viscosity of the slurry,
and the like.
For example, the width W1, along the transverse axis 60, of the distribution
outlet 130
for use in a wallboard manufacturing process, which conventionally is provided
in
nominal widths no greater than fifty-four inches, can be within a range from
about
eight to about fifty-four inches in some embodiments, and in other embodiments
within a range from about eighteen inches to about thirty inches. In other
embodiments, the ratio of the width W1, along the transverse axis 60, of the
distribution outlet 130 to the maximum nominal width of the panel being
produced on
the manufacturing system using the slurry distributor constructed according to
principles of the present disclosure can be in a range from about 1/7 to about
1, in a
range from about 1/3 to about 1 in other embodiments, in a range from about
1/3 to
about 2/3 in yet other embodiments, and in a range from about 1/2 to about 1
in still
other embodiments.
[00164] The height of the distribution outlet can be within a range from about
3/16
inch to about two inches in some embodiments, and in other embodiments between
about 3/16 inch and about an inch. In some embodiments including a rectangular
distribution outlet, the ratio of the rectangular width to the rectangular
height of the
outlet opening can be about 4 or more, in other embodiments about 8 or more,
in
some embodiments from about 4 to about 288, in other embodiments from about 9
to about 288, in other embodiments from about 18 to about 288, and in still
other
embodiments from about 18 to about 160.
[00165] The distribution conduit 128 includes a converging portion 182 in
fluid
communication with the entry portion 152. The height of the converging portion
182
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is less than the height at the maximum cross-sectional flow area of the first
and
second shaped ducts 141, 143 and less than the height of the opening 181 of
the
distribution outlet 130. In some embodiments, the height of the converging
portion
182 can be about half the height of the opening 181 of the distribution outlet
130.
[00166] The converging portion 182 and the height of the distribution outlet
130
can cooperate together to help control the average velocity of the combined
first and
second flows of aqueous calcined gypsum being distributed from the
distribution
conduit 128. The height and/or width of the distribution outlet 130 can be
varied to
adjust the average velocity of the combined first and second flows of slurry
discharging from the slurry distributor 120.
[00167] In some
embodiments, the outlet flow direction 192 is substantially parallel
to the plane 57 defined by the machine direction 50 and the transverse cross-
machine direction 60 of the system transporting the advancing web of cover
sheet
material. In other embodiments, the first and second feed directions 190, 191
and
the outlet flow direction 192 are all substantially parallel to the plane 57
defined by
the machine direction 50 and the transverse cross-machine direction 60 of the
system transporting the advancing web of cover sheet material. In some
embodiments, the slurry distributor can be adapted and arranged with respect
to the
forming table such that the flow of slurry is redirected in the slurry
distributor 120
from the first and second feed directions 190, 191 to the outlet flow
direction 192
without undergoing substantial flow redirection by rotating about the cross-
machine
direction 60.
[00168] In some embodiments, the slurry distributor can be adapted and
arranged
with respect to the forming table such that the first and second flows of
slurry are
redirected in the slurry distributor from the first and second feed directions
190, 191
to the outlet flow direction 192 by redirecting the first and second flows of
slurry by
rotating about the cross-machine direction 60 over an angle of about forty-
five
degrees or less. Such a rotation can be accomplished in some embodiments by
adapting the slurry distributor such that the first and second feed inlets
124, 125 and
the first and second feed directions 190, 191 of the first and second flows of
slurry
are disposed at a vertical offset angle w with respect to the vertical axis 55
and the
plane 57 formed by the machine axis 50 and the cross-machine axis 60. In
embodiments, the first and second feed inlets 124, 125 and the first and
second feed
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directions 190, 191 of the first and second flows of slurry can be disposed at
a
vertical offset angle w within a range from zero to about sixty degrees such
that the
flow of slurry is redirected about the machine axis 50 and moves along the
vertical
axis 55 in the slurry distributor 120 from the first and second feed
directions 190, 191
to the outlet flow direction 192. In embodiments, at least one of the
respective entry
segment 136, 137 and the shaped ducts 141, 143 can be adapted to facilitate
the
redirection of the slurry about the machine axis 50 and along the vertical
axis 55. In
embodiments, the first and second flows of slurry can be redirected from the
first and
second feed directions 190, 191 through a change in direction angle a about an
axis
substantially perpendicular to vertical offset angle w and/or one or more
other
rotational axes within a range of about forty-five degrees to about one
hundred fifty
degrees to the outlet flow direction 192 such that the outlet flow direction
192 is
generally aligned with the machine direction 50.
[00169] In use, first and second flows of aqueous calcined gypsum slurry pass
through the first and second feed inlets 124, 125 in converging first and
second feed
directions 190, 191. The first and second shaped ducts 141, 143 redirect the
first
and second flows of slurry from the first feed direction 190 and the second
feed
direction 191 so that the first and second flows of slurry move over a change
in
direction angle a from both being substantially parallel to the transverse
axis 60 to
both being substantially parallel to the machine direction 50. The
distribution conduit
128 can be positioned such that it extends along the longitudinal axis 50
which
substantially coincides with the machine direction 50 along which a web of
cover
sheet material moves in a method making a gypsum board. The first and second
flows of aqueous calcined gypsum slurry combine in the slurry distributor 120
such
that the combined first and second flows of aqueous calcined gypsum slurry
pass
through the distribution outlet 130 in the outlet flow direction 192 generally
along the
longitudinal axis 50 and in the direction of the machine direction.
[00170] Referring to FIG. 2, a slurry distributor support 100 can be
provided to help
support the slurry distributor 120, which in the illustrated embodiment is
made from a
flexible material, such as PVC or urethane, for example. The slurry
distributor
support 100 can be made from a suitable rigid material to help support the
flexible
slurry distributor 120. The slurry distributor support 100 can include a two-
piece
construction. The two pieces 101, 103 can be pivotally movable with respect to
each
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other about a hinge 105 at the rear end thereof to allow for ready access to
an
interior 107 of the support 100. The interior 107 of the support 100 can be
configured such that the interior 107 substantially conforms to the exterior
of the
slurry distributor 120 to help limit the amount of movement the slurry
distributor 120
can undergo with respect to the support 100 and/or to help define the interior
geometry of the slurry distributor 120 through which a slurry will flow.
[00171] Referring to FIG. 3, in some embodiments, the slurry distributor
support
100 can be made from a suitable resiliently flexible material that provides
support
and is able to be deformed in response to the profiling system 132 mounted to
the
support 100. The profiling system 132 can be mounted to the support 100
adjacent
the distribution outlet 130 of the slurry distributor 120. The profiling
system 132 so
installed can act to vary the size and/or shape of the distribution outlet 130
of the
distribution conduit 128 by also varying the size and/or shape of the closely
conforming support 100, which in turn, influences the size and/or shape of the
distribution outlet 130.
[00172] Referring to FIG. 3, the profiling system 132 can be adapted to
selectively
change the size and/or shape of the opening 181 of the distribution outlet
130. In
some embodiments, the profiling system can be used to selectively adjust the
height
H1 of the opening 181 of the distribution outlet 130.
[00173] The illustrated profiling system 132 includes a plate 90, a
plurality of
mounting bolts 92 securing the plate to the distribution conduit 128, and a
series of
adjustment bolts 94, 95 threadingly secured thereto. The mounting bolts 92 are
used to secure the plate 90 to the support 100 adjacent the distribution
outlet 130 of
the slurry distributor 120. The plate 90 extends substantially along the
transverse
axis 60. In the illustrated embodiment, the plate 90 is in the form of a
length of angle
iron. In other embodiments, the plate 90 can have different shapes and can
comprise different materials. In still other embodiments, the profiling system
can
include other components adapted to selectively change the size and/or shape
of the
opening 181 of the distribution outlet 130.
[00174] The illustrated profiling system 132 is adapted to locally vary along
the
transverse axis 60 the size and/or shape of the opening 181 of the
distribution outlet
130. The adjustment bolts 94, 95 are in regular, spaced relationship to each
other
along the transverse axis 60 over the distribution outlet 130. The adjustment
bolts
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94, 95 are independently adjustable to locally vary the size and/or shape of
the
distribution outlet 130.
[00175] The profiling system 132 can be used to locally vary the distribution
outlet
130 so as to alter the flow pattern of the combined first and second flows of
aqueous
calcined gypsum slurry being distributed from the slurry distributor 120. For
example, the mid-line adjustment bolt 95 can be tightened down to constrict
the
transverse central midpoint 187 of the distribution outlet 130 to increase the
edge
flow angle away from the longitudinal axis 50 to facilitate spreading in the
cross-
machine direction 60 and to improve the slurry flow uniformity in the cross-
machine
direction 60.
[00176] The profiling system 132 can be used to vary the size of the
distribution
outlet 130 along the transverse axis 60 and maintain the distribution outlet
130 in the
new shape. The plate 90 can be made from a material that is suitably strong
such
that the plate 90 can withstand opposing forces exerted by the adjustment
bolts 94,
95 in response to adjustments made by the adjustment bolts 94, 95 in urging
the
distribution outlet 130 into a new shape. The profiling system 132 can be used
to
help even out variations in the flow profile of the slurry (for example, as a
result of
different slurry densities and/or different feed inlet velocities) being
discharged from
the distribution outlet 130 such that the exit pattern of the slurry from the
distribution
conduit 128 is more uniform.
[00177] In other embodiments, the number of adjustment bolts can be varied
such
that the spacing between adjacent adjustment bolts changes. In other
embodiments,
such as where the width W1 of the distribution outlet 130 is different, the
number of
adjustment bolts can also be varied to achieve a desired adjacent bolt
spacing. In
yet other embodiments, the spacing between adjacent bolts can vary along the
transverse axis 60, for example to provide greater locally-varying control at
the side
edges 183, 185 of the distribution outlet 130.
[00178] A slurry distributor constructed in accordance with principles of the
present
disclosure can comprise any suitable material. In some embodiments, a slurry
distributor can comprise any suitable substantially rigid material which can
include a
suitable material which can allow the size and shape of the outlet to be
modified
using a profile system, for example. For example, a suitably rigid plastic,
such as
ultra-high molecular weight (UHMW) plastic, or metal can be used. In other
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embodiments, a slurry distributor constructed in accordance with principles of
the
present disclosure can be made from a flexible material, such as a suitable
flexible
plastic material, including poly vinyl chloride (PVC) or urethane, for
example. In
some embodiments, a slurry distributor constructed in accordance with
principles of
the present disclosure can include a single feed inlet, entry segment, and
shaped
duct which is in fluid communication with a distribution conduit.
[00179] A gypsum slurry distributor constructed in accordance with principles
of
the present disclosure can be used to help provide a wide cross machine
distribution
of aqueous calcined gypsum slurry to facilitate the spreading of high
viscous/lower
WSR gypsum slurries on a web of cover sheet material moving over a forming
table.
The gypsum slurry distribution system can be used to help control air-slurry
phase
separation, as well.
[00180] In accordance with another aspect of the present disclosure, a gypsum
slurry mixing and dispensing assembly can include a slurry distributor
constructed in
accordance with principles of the present disclosure. The slurry distributor
can be
placed in fluid communication with a gypsum slurry mixer adapted to agitate
water
and calcined gypsum to form an aqueous calcined gypsum slurry. In one
embodiment, the slurry distributor is adapted to receive a first flow and a
second flow
of aqueous calcined gypsum slurry from the gypsum slurry mixer and distribute
the
first and second flows of aqueous calcined gypsum slurry onto an advancing
web.
[001811 The slurry distributor can comprise a part of, or act as, a discharge
conduit
of a conventional gypsum slurry mixer (e.g., a pin mixer) as is known in the
art. The
slurry distributor can be used with components of a conventional discharge
conduit.
For example, the slurry distributor can be used with components of a gate-
canister-
boot arrangement as known in the art or of the discharge conduit arrangements
described in U.S. Patent Nos. 6,494,609; 6,874,930; 7,007,914; and 7,296,919.
[00182] A slurry distributor constructed in accordance with principles of the
present
disclosure can advantageously be configured as a retrofit in an existing
wallboard
manufacturing system. The slurry distributor preferably can be used to replace
a
conventional single or multiple-branch boot used in conventional discharge
conduits.
This gypsum slurry distributor can be retrofitted to an existing slurry
discharge
conduit arrangement, such as that shown in U.S. Patent No. 6,874,930 or
7,007,914,
for example, as a replacement for the distal dispensing spout or boot.
However, in
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some embodiments, the slurry distributor may, alternatively, be attached to
one or
more boot outlet(s).
[00183]
Referring to FIGS. 4 and 5, the slurry distributor 220 is similar to the
slurry
distributor 120 of FIGS. 1-3, except that it is constructed from a
substantially rigid
material. The interior geometry 207 of the slurry distributor 220 of FIGS. 4
and 5 is
similar to that of the slurry distributor 120 of FIGS. 1-3, and like reference
numerals
are used to indicate like structure. The interior geometry 207 of the slurry
distributor
207 is adapted to define a flow path for the gypsum slurry traveling
therethrough
which is of the manner of a streamline flow, undergoing reduced or
substantially no
air-liquid slurry phase separation and substantially without undergoing a
vortex flow
path.
[00184] In some embodiments, the slurry distributor 220 can comprise any
suitable
substantially rigid material which can include a suitable material which can
allow the
size and shape of the outlet 130 to be modified using a profile system, for
example.
For example, a suitably rigid plastic, such as UHMW plastic, or metal can be
used.
[00185] Referring to FIG. 4, the slurry distributor 220 has a two-piece
construction.
An upper piece 221 of the slurry distributor 220 includes a recess 227 adapted
to
receive a profiling system 132 therein. The two pieces 221, 223 can be
pivotally
movable with respect to each other about a hinge 205 at the rear end thereof
to
allow for ready access to an interior 207 of the slurry distributor 220.
Mounting holes
229 are provided to facilitate the connection of the upper piece 221 and its
mating
lower piece 223.
[00186] Referring to FIGS. 6-8, another embodiment of a slurry distributor 320
constructed in accordance with principles of the present disclosure is shown
which is
constructed from a rigid material. The slurry distributor 320 of FIGS. 6-8 is
similar to
the slurry distributor 220 of FIGS. 4 and 5 except that the first and second
feed inlets
324, 325 and the first and second entry segments 336, 337 of the slurry
distributor
320 of FIGS. 6-8 are disposed at a feed angle 8 with respect to the
longitudinal axis
or machine direction 50 of about 60 (see FIG. 7).
[00187] The slurry distributor 320 has a two-piece construction including an
upper
piece 321 and its mating lower piece 323. The two pieces 321, 323 of the
slurry
distributor 320 can be secured together using any suitable technique, such as
by
using fasteners through a corresponding number of mounting holes 329 provided
in
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each piece 321, 323, for example. The upper piece 321 of the slurry
distributor 320
includes a recess 327 adapted to receive a profiling system 132 therein. The
slurry
distributor 320 of FIGS. 6-8 is similar in other respects to the slurry
distributor 220 of
FIGS. 4 and 5.
[00188] Referring to FIGS. 9 and 10, the lower piece 323 of the slurry
distributor
320 of FIG. 6 is shown. The lower piece 323 defines a first portion 331 of the
interior
geometry 307 of the slurry distributor 320 of FIG. 6. The upper piece 323
defines a
symmetrical second portion of the interior geometry 307 such that when the
upper
and lower pieces 321, 323 are mated together, as shown in FIG. 6, they define
the
complete interior geometry 307 of the slurry distributor 320 of FIG. 6.
[00189] Referring to FIG. 9, the first and second shaped ducts 341, 343 are
adapted to receive the first and second flows of slurry moving in the first
and second
feed flow directions 390, 391 and redirect the slurry flow direction by a
change in
direction angle a such that the first and second flows of slurry are conveyed
into the
distribution conduit 328 moving substantially in the outlet flow direction
392, which is
aligned with the machine direction or longitudinal axis 50.
[00190] FIGS. 11 and 12 depict another embodiment of a slurry distributor
support
300 for use with the slurry distributor 320 of FIG. 6. The slurry distributor
support
300 can include a top and bottom support plate 301, 302 constructed from a
suitably
rigid material, such as metal, for example. The support plates 301, 302 can be
secured to the distributor through any suitable means. In use, the support
plates
301, 302 can help support the slurry distributor 320 in place over a machine
line
including a conveyor assembly supporting and transporting a moving cover
sheet.
The support plates 301, 302 can be mounted to appropriate uprights placed on
either
side of the conveyor assembly.
[00191] FIGS. 13 and 14 depict yet another embodiment of a slurry
distributor
support 310 for use with the slurry distributor 320 of FIG. 6, which also
includes top
and bottom support plates 311, 312. Cutouts 313, 314, 318 in the top support
plate
311 can make the support 310 lighter than it would otherwise be and provide
access
to portions of the slurry distributor 320, such as those portions
accommodating
mounting fasteners, for example. The slurry distributor support 310 of FIGS.
13 and
14 can be similar in other respects to the slurry distributor support 300 of
FIGS. 11
and 12.
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[00192] FIGS. 15-19 illustrate another embodiment of a slurry distributor
420,
which is similar to the slurry distributor 320 of FIGS. 6-8, except that it is
constructed
from a substantially flexible material. The slurry distributor 420 of FIGS. 15-
19 also
includes first and second feed inlets 324, 325 and first and second entry
segments
336, 337 which are disposed at a feed angle 0 with respect to the longitudinal
axis or
machine direction 50 of about 60 (see FIG. 7). The interior geometry 307 of
the
slurry distributor 420 of FIGS. 15-19 is similar to that of the slurry
distributor 320 of
FIGS. 6-8, and like reference numerals are used to indicate like structure.
[00193] FIGS. 17-19 progressively depict the interior geometry of the second
entry
segment 337 and the second shaped duct 343 of the slurry distributor 420 of
FIGS.
15 and 16. The cross-sectional areas 411, 412, 413, 414 of the outer and inner
guide channels 367, 368 can become progressively smaller moving in a second
flow
direction 397 toward the distribution outlet 330. The outer guide channel 367
can
extend substantially along the outer wall 357 of the second shaped duct 343
and
along the sidewall 353 of the distribution conduit 328 to the distribution
outlet 330.
The inner guide channel 368 is adjacent the inner wall 358 of the second
shaped
duct 343 and terminates at the peak 375 of the bisected connector segment 339.
The slurry distributor 420 of FIGS. 15-19 is similar in other respects to the
slurry
distributor 120 of FIG. 1 and the slurry distributor 320 of FIG. 6.
[00194] Referring to FIGS. 20 and 21, the illustrated embodiment of the
slurry
distributor 420 is made from a flexible material, such as PVC or urethane, for
example. A slurry distributor support 400 can be provided to help support the
slurry
distributor 420. The slurry distributor support 400 can include a support
member,
which in the illustrated embodiment is in the form of a bottom support tray
401 filled
with a suitable supporting medium 402 which defines a supporting surface 404.
The
supporting surface 404 is configured to substantially conform to at least a
portion of
an exterior of at least one of the feed conduit 322 and the distribution
conduit 328 to
help limit the amount of relative movement between the slurry distributor 420
and the
support tray 401. In some embodiments, the supporting surface 404 can also
help
maintain the interior geometry of the slurry distributor 420 through which a
slurry will
flow.
[00195] The slurry distributor support 400 can also include a movable support
assembly 405 disposed in spaced relationship to bottom support tray 401. The
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movable support assembly 405 can be positioned above the slurry distributor
420
and adapted to be placed in supporting relationship with the slurry
distributor 420 to
help maintain the interior geometry 307 of the slurry distributor in a desired
configuration.
[00196] The movable support assembly 405 can include a support frame 407 and
a plurality of support segments 415, 416, 417, 418, 419 which are movably
supported by the support frame 407. The support frame 407 can be mounted to at
least one of the bottom support tray 401 or a suitably arranged upright or
uprights to
retain the support frame 407 in fixed relationship to the bottom support tray
401.
[00197] In embodiments, at least one support segment 415, 416, 417, 418, 419
is
independently movable relative to another support segment 415, 416, 417, 418,
419.
In the illustrated embodiment, each support segment 415, 416, 417, 418, 419
can be
independently movable relative to the support frame 407 over a predetermined
range
of travel. In embodiments, each support segment 415, 416, 417, 418, 419 is
movable over a range of travel such that each support segment is in a range of
positions over which the respective support segment 415, 416, 417, 418, 419 is
in
increasing compressive engagement with a portion of at least one of the feed
conduit
322 and the distribution conduit 328.
[00198] The position of each support segment 415, 416, 417, 418, 419 can be
adjusted to place the support segments 415, 416, 417, 418, 419 in compressive
engagement with at least a portion of the slurry distributor 420. Each support
segment 415, 416, 417, 418, 419 can be independently adjusted to place each
support segment 415, 416, 417, 418, 419 either in further compressive
engagement
with at least a portion of the slurry distributor 420, thereby locally
compressing the
interior of the slurry distributor 420, or in reduced compressive engagement
with at
least a portion of the slurry distributor 420, thereby allowing the interior
of the slurry
distributor 420 to expand outwardly, such as in response to aqueous gypsum
slurry
flowing therethrough.
[00199] In the illustrated embodiment, each of the support segments 415, 416,
417
is movable over a range of travel along the vertical axis 55. In other
embodiments,
at least one of the support segments can be movable along a different line of
action.
[00200] The movable support assembly 405 includes a clamping mechanism 408
associated with each support segment 415, 416, 417, 418, 419. Each clamping
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mechanism 408 can be adapted to selectively retain the associated support
segment
415, 416, 417, 418, 419 in a selected position relative to the support frame
407.
[00201] In the illustrated embodiment, a rod 409 is mounted to each support
segment 415, 416, 417, 418, 419 and extends upwardly through a corresponding
opening in the support frame 407. Each clamping mechanism 408 is mounted to
the
support frame 407 and is associated with one of the rods 409 projecting from a
respective support segment 415, 416, 417, 418, 419. Each clamping mechanism
408 can be adapted to selectively retain the associated rod 409 in fixed
relationship
to the support frame 407. The illustrated clamping mechanisms 408 are
conventional lever-actuated clamps which encircle the respective rod 409 and
allow
for infinitely variable adjustment between the clamping mechanism 408 and the
associated rod 409.
[00202] As one skilled in the art will appreciate, any suitable clamping
mechanism
408 can be used in other embodiments. In some embodiments, each associated rod
409 can be moved via a suitable actuator (either hydraulic or electric, e.g.)
which is
controlled via a controller. The actuator can function as a clamping mechanism
by
retaining the associated support segment 415, 416, 417, 418, 419 in a fixed
position
relative to the support frame 407.
[00203] Referring to FIG. 21, the support segments 415, 416, 417, 418, 419 can
each include a contacting surface 501, 502, 503, 504, 505 which is configured
to
substantially conform to a surface portion of the desired geometric shape of
at least
one of the feed conduit 322 and the distribution conduit 328 of the slurry
distributor
420. In the illustrated embodiment, a distributor conduit support segment 415
is
provided which includes a contacting surface 501 which conforms to the
exterior and
interior shape of a portion of the distributor conduit 328 over which the
distributor
conduit support segment 415 is disposed. A pair of shaped duct support
segments
416, 417 is provided which respectively include a contacting surface 502, 503
which
conforms to the exterior and interior shape of a portion of the first and the
second
shaped ducts 341, 343, respectively, over which the shaped duct support
segments
416, 417 are disposed. A pair of entry support segments 418, 419 is provided
which
respectively include a contacting surface 504, 505 which conforms to the
exterior
and interior shape of a portion of the first and the second entry segments
336, 337,
respectively, over which the shaped duct support segments 418, 419 are
disposed.
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The contacting surfaces 501, 502, 503, 504, 505 are adapted to be placed in
contacting relationship with a selected portion of the slurry distributor 420
to help
maintain the contacted portion of the slurry distributor 420 in position to
help define
the interior geometry 307 of the slurry distributor 420.
[00204] In use, the movable support assembly 405 can be operated to place each
support segment 415, 416, 417, 418, 419 independently in a desired
relationship
with the slurry distributor 420. The support segments 415, 416, 417, 418, 419
can
help maintain the interior geometry 307 of the slurry distributor 420 to
promote the
flow of slurry therethrough and to help ensure the volume defined by the
interior
geometry 307 is substantially filled with slurry during use. The location of
the
particular contacting surface of a given support segment 415, 416, 417, 418,
419 can
be adjusted to modify locally the interior geometry of the slurry distributor
420. For
example, the distributor conduit support segment 415 can be moved along the
vertical axis 55 closer to the bottom support tray 401 to decrease the height
of the
distribution conduit 328 in an area over which the distributor conduit support
segment 415 is.
[00205] In other embodiments, the number of support segments can be varied. In
still other embodiments, the size and/or shape of a given support segment can
be
varied.
[00206] FIGS. 22-27 illustrate another embodiment of a slurry distributor
1420
constructed according to principles of the present disclosure. The slurry
distributor
1420 is made from a substantially flexible material, such as PVC or urethane,
for
example. The slurry distributor 1420 of FIGS. 22-27 also includes first and
second
feed inlets 1424, 1425 and first and second entry segments 1436, 1437 which
are
disposed at a feed angle 0 which is substantially parallel to the longitudinal
axis or
machine direction 50 (see FIG. 24).
[00207] The slurry distributor 1420 includes a bifurcated feed conduit 1422, a
distribution conduit 1428, a slurry wiping mechanism 1417, and a profiling
mechanism 1432. A slurry distributor support 1400 can be provided to help
support
the slurry distributor 1420.
[00208] Referring to FIGS. 22 and 23, the slurry distributor support 1400 can
include a support member, which in the illustrated embodiment is in the form
of a
bottom support member 1401 which defines a supporting surface 1402. The
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supporting surface 1402 can be configured to substantially conform to at least
a
portion of an exterior of at least one of the feed conduit 1422 and the
distribution
conduit 1428 to help limit the amount of relative movement between the slurry
distributor 1420 and the bottom support member 1401. In some embodiments, the
supporting surface 1402 can also help maintain the interior geometry of the
slurry
distributor 1420 through which a slurry will flow. In embodiments, additional
anchoring structure can be provided to help secure the slurry distributor 1420
to the
bottom support member 1401.
[00209] The slurry distributor support 1400 can also include an upper support
member 1404 disposed in spaced relationship to the bottom support member 1401.
The upper support member 1404 can be positioned above the slurry distributor
1420
and adapted to be placed in supporting relationship with the slurry
distributor 1420 to
help maintain the interior geometry 1407 of the slurry distributor 1420 in a
desired
configuration.
[00210] The upper support member 1404 can include a support frame 1407 and a
plurality of support segments 1413, 1415, 1416 which are fixedly supported by
the
support frame 1407. The support frame 1407 can be mounted to at least one of
the
bottom support member 1401 or one or more suitably arranged uprights to retain
the
support frame 1407 in fixed relationship to the bottom support tray 1401. The
support segments 1413, 1415, 1416 can each have contacting surface which is
configured to substantially conform to a surface portion of the desired
geometric
shape of at least one of the feed conduit 1422 and the distribution conduit
1428 of
the slurry distributor 1420. In embodiments, the support frame 1407 can be
adapted
to movably adjust the spatial relationship between the support segments 1413,
1415,
1416 and the slurry distributor 1420. For example in some embodiments, the
support frame 1407 can move the support segments 1413, 1415, 1416 over a range
of travel over the vertical axis 55.
[00211] Referring to FIG. 22, the slurry wiping mechanism 1417 includes a
pair of
actuators 1510, 1511 operably arranged with a wiper blade 1514 to selectively
reciprocally move the wiper blade 1514. The actuators 1510, 1511 are mounted
to
the bottom support member 1401 adjacent a distal end 1515 of the distribution
conduit 1428. The wiper blade 1514 extends transversely between the actuators
1510, 1511.
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[00212] Referring to FIG. 26, the distribution outlet 1430 includes an
outlet opening
1481 having a width W2, along the transverse axis 60. The wiper blade 1514
extends a predetermined width W3 distance along the transverse axis 60. The
width
W2 of the outlet opening 1481 is smaller than the width W3 of the wiper blade
1514
such that the wiper blade 1514 is wider than the outlet opening 1481.
[00213] Referring to FIG. 28, in the illustrated embodiments, each actuator
1510,
1511 comprises a double-acting pneumatic cylinder having a reciprocally
movable
piston 1520. A rod 1522 of the piston 1520 is connected to the wiper blade
1514. In
embodiments, a pair of pneumatic air lines can be respectively connected to a
drive
port 1525 and a retract port 1526. A source of pressurized gas 1530 can be
controlled using a suitable control valve assembly 1532 controlled by a
controller
1534 to selectively reciprocally move the wiper blade 1514 along the
longitudinal
axis 50. In embodiments an air line can tie the drive ports 1525 of both
actuators
1510, 1511 together in parallel, and a separate air line can tie the retract
ports 1526
of both actuators 1510, 1511 together in parallel. In other embodiments, the
actuators can be anything capable of reciprocally moving the wiper blade
including,
for example, hand operated devices.
[00214] The movable wiper blade 1514 is in contacting relationship with a
bottom
surface 1540 of the distribution conduit 1428. The wiper blade 1514 is
reciprocally
movable over a clearing path between a first position and a second position
(shown
in phantom lines). The clearing path is disposed adjacent the distal end 1515
of the
distribution conduit 1428 which includes the distribution outlet 1430. The
wiper blade
reciprocally moves longitudinally along the clearing path. In the illustrated
embodiment, the first position of the wiper blade 1514 is longitudinally
upstream of
the distribution outlet 1430, and the second position is longitudinally
downstream of
the distribution outlet 1430.
[00215] The controller 1534 is adapted to selectively control the actuators to
reciprocally move the wiper blade 1514. In embodiments, the controller 1534 is
adapted to move the wiper blade 1514 in a clearing direction 1550 from the
first
position to the second position over a wiping stroke and to move the wiper
blade in
an opposing, return direction 1560 from the second position to the first
position over
a return stroke. In embodiments, the controller 1534 is adapted to move the
wiper
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blade 1514 such that the time to move over the wiping stroke is substantially
the
same as the time to move over the return stroke.
[00216] In embodiments, the controller 1534 can be adapted to move the wiper
blade 1514 reciprocally between the first position and the second position in
a cycle
having a sweep period. The sweep period includes a wiping portion comprising
the
time to move over the wiping stroke, a returning portion comprising the time
to move
over the return stroke, and an accumulation delay portion comprising a
predetermined period of time in which the wiper blade 1514 remains in the
first
position. In embodiments, the wiping portion is substantially the same as the
returning portion. In embodiments, the controller 1534 is adapted to
adjustably vary
the accumulation delay portion.
[00217] Referring to FIG. 34, the bottom support member 1401 supporting the
bottom surface of the distribution conduit 1428 includes a perimeter 1565. The
distribution outlet 1430 is longitudinally offset from the bottom support
member 1401
such that the distal outlet portion 1515 of the distribution conduit 1428
extends from
the perimeter 1565 of the bottom support member 1401. Referring back to FIG.
28,
the wiper blade 1514 supports the distal outlet portion 1515 of the slurry
distributor
1420 when the wiper blade is in the first position.
[00218] Referring to FIG. 22, the profiling mechanism 1432 includes a
profiling
member 1610 in contacting relationship with the distribution conduit 1428 and
a
support assembly 1620 adapted to allow the profiling member 1610 to have at
least
two degrees of freedom. In embodiments, the profiling member is translatable
along
at least one axis and rotatable about at least one pivot axis. In embodiments
the
profiling member is movable along the vertical axis 55 and rotatable about a
pivot
axis 1630 that is substantially parallel to the longitudinal axis 50.
[00219] Referring to FIGS. 26, 30 and 30A, the profiling member 1610 is
movable
over a range of travel such that the profiling member 1610 is in a range of
positions
over which the profiling member 1610 is in increasing compressive engagement
with
a portion of the distribution conduit 1428 adjacent the distribution outlet
1430 to vary
the shape and/or size of the outlet opening 1430.
[00220] Referring to FIG. 26, the outlet opening 1481 of the distribution
outlet 1430
has a width W2 along the transverse axis 60. The contacting profiling segment
of the
profiling member 1410 has a width W4 extending a predetermined distance along
the
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transverse axis. In embodiments the width W2 of the outlet opening 1481 is
larger
than the width W4 of the profiling member 1410. In other embodiments the width
W2
of the outlet opening 1481 is less than or equal to the width W4 of the
profiling
member 1410. The profiling member 1410 is positioned such that a pair of
lateral
portions 1631, 1632 of the distribution outlet 1430 is in lateral offset
relationship to
the profiling member 1410 such that the profiling member does not engage the
lateral portions 1631, 1632. In some embodiments, the lateral portions 1631,
1632
can have a combined width of about one-fourth of the width W2 the outlet
opening
1481.
[00221] Referring to FIG. 23, the support assembly 1620 includes a pair of
stationary uprights 1642, 1643, a transverse stationary support member 1645,
and a
transverse pivotal support member 1647 that is pivotally connected to the
transverse
stationary support member 1645 using any suitable pivotal connection. The
stationary uprights 1642, 1643 can be mounted to the bottom support member
1401.
The transverse stationary support member 1645 can extend transversely between
the stationary uprights 1642, 1643.
[00222] Referring to FIGS. 29, 30, 30B, and 31, the pivotal support member
1647
is rotatable about the pivot axis 1630 over an arc length 1652 with respect to
the
stationary support member 1645. In embodiments, the arc length 1652 allows for
tilting a pivot end 1653 of the pivotal support member 1647 both upward above
the
transverse axis 60 and downward below the transverse axis 60. The pivotal
support
member 1647 supports the profiling member 1610.
[00223] In embodiments, the profiling member 1610 is translatable along the
vertical axis 55 and rotatable about the pivot axis 1630 which is
substantially parallel
to the longitudinal axis 50. The profiling member 1610 is rotatable about the
pivot
axis 1630 over the arc length 1652 such that the profiling member 1610 is in a
range
of positions over which the profiling member is in variable compressive
engagement
with the portion of the distribution conduit 1428 across the transverse axis
60 such
that the height H2 of the outlet opening 1481 varies along the transverse axis
60.
[00224] Referring to FIGS. 29 and 33, the profiling member 1610 includes an
engagement segment 1660 extending generally longitudinally and transversely
and a
translation adjustment rod 1662 extending generally vertically from the
engagement
segment 1660. The translation adjustment rod 1662 of the profiling member 1610
is
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movably secured to the pivotal support member 1647 of the support assembly
1620
such that the profiling member 1610 is movable along the vertical axis 55 over
a
range of vertical positions. A pair of translation guide rods 1663, 1665 are
connected to the engagement segment 1660 and extends through a respective
collar
1667, 1668 mounted to the pivotal support member 1647. The guide rods 1663,
1665 are movable with respect to the collars 1667, 1668 along the vertical
axis 55.
[00225] The support assembly 1620 can include a clamp mechanism adapted to
selectively engage the translation adjustment rod 1662 to secure the profiling
member 1610 in a selected one of the range of vertical positions. In the
illustrated
embodiment, a threaded connection between the translation adjustment rod 1662
and the pivotal support member 1647 functions as a clamp mechanism. A lock nut
1664 is provided to secure the threaded translation adjustment rod 1662 in
place.
An elastic nut 1666 is disposed near a distal end 1657 of the translation
adjustment
rod 1662 to maintain a sufficient clearance for a cap screw 1669 (see FIG.
300)
affixed to the distal end to be allowed to rotate. Referring to FIG. 30C, a
blind hole
1658 is defined in the profiling member 1610 to accommodate the cap screw 1669
to
allow the cap screw to rotate about the axis of the translation adjustment rod
1662.
[00226] Referring to FIGS. 30B and 31, the support assembly 1620 can be
adapted to rotatably support the profiling member 1610 such that the profiling
member 1610 is rotatable about the pivot axis 1630 over a range of positions
along
the arc length 1652. The support assembly 1620 includes a rotation adjustment
rod
1670 extending between the stationary support member 1645 and the pivotal
support member 1647 by way of a support bracket 1672 connected to the
stationary
support member 1645 (see FIG. 31 also). The rotation adjustment rod 1670 is
movably secured to the stationary support member 1645 through a threaded
connection with the support bracket 1672 such that moving the rotation
adjustment
rod 1670 with respect to the stationary support member 1645, by rotating its T-
handle, pivots the pivotal support member 1647 about the pivot axis 1630 with
respect to the stationary support member 1645. The support bracket 1672 can be
configured such that it can allow for some flexing during a tilt operation.
Shaft collars
1673, 1674 can be provided for added reliability.
[00227] The support assembly 1620 can include a clamp mechanism adapted to
selectively engage the rotation adjustment rod 1670 to secure the profiling
member
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1610 in a selected one of the range of positions along the arc length 1652. In
the
illustrated embodiment, a jam nut 1677 can be provided to lock the threaded
rod
1670 to the barrel nut 1679.
[00228] Referring to FIGS. 34 and 40, the bifurcated feed conduit 1422 of the
slurry distributor 1420 includes a first and a second feed portion 1701, 1702.
Each
of the first and second feed portions 1701, 1702 has a respective entry
segment
1436, 1437 with a feed inlet 1424, 1425 and a feed entry outlet 1710, 1711 in
fluid
communication with the feed inlet 1424, 1425, a shaped duct 1441, 1443 having
a
bulb portion 1720, 1721 (see FIG. 41 also) in fluid communication with the
feed entry
outlet 1710, 1711 of the respective entry segment 1436, and a transition
segment
1730, 1731 in fluid communication with the respective bulb portion 1720, 1721.
[00229] Referring to FIG. 34, the first and second feed inlets 1424, 1425 and
the
first and second entry segments 1436, 1437 can be disposed at a respective
feed
angle 0, measured as the degree of rotation relative to the vertical axis 55,
in a range
up to about 1350 with respect to the longitudinal axis 50. The illustrated
first and
second feed inlets 1424, 1425 and the first and second entry segments 1436,
1437
are disposed at a respective feed angle 0 substantially aligned with the
longitudinal
axis 50.
[00230] The first feed portion 1701 is substantially identical the second feed
portion 1702. It should be understood, therefore, that the description of one
feed
portion is equally applicable to the other feed portion, as well. In other
embodiments
there can be only a single feed portion or in still further embodiments there
can be
more than two feed portions.
[00231] Referring to FIG. 35, the entry segment 1436 is generally
cylindrical and
extends along a first feed flow axis 1735. The first feed flow axis 1735 of
the
illustrated entry segment 1436 extends generally along the vertical axis 55.
[00232] In other embodiments, the first feed flow axis 1735 can have a
different
orientation with respect to the plane 57 defined by the longitudinal axis 50
and the
transverse axis 60. For example, in other embodiments, the first feed flow
axis 1735
can be disposed at a feed pitch angle a, measured as the degree of rotation
relative
to the transverse axis 60, that is non-perpendicular to the plane 57 defined
by the
longitudinal axis 50 and the transverse axis 60. In embodiments the pitch
angle a,
measured from the longitudinal axis 50 in a direction opposing the machine
direction
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range
from about zero to about one hundred thirty-five degrees, from about fifteen
to about
one hundred twenty degrees in other embodiments, from about thirty to about
one
hundred five degrees in still other embodiments, from about forty-five to
about one
hundred five degrees in yet other embodiments, and from about seventy-five to
about one hundred five degrees in other embodiments. In other embodiments, the
first feed flow axis 1735 can be disposed at a feed roll angle, measured as
the
degree of rotation relative to the longitudinal axis 50, that is non-
perpendicular to the
plane 57 defined by the longitudinal axis 50 and the transverse axis 60.
[00233] Referring to FIG. 34, the shaped duct 1441 includes a pair of
lateral
sidewalls 1740, 1741 and the bulb portion 1720. The shaped duct 1441 is in
fluid
communication with the feed entry outlet 1711 of the entry segment 1436.
Referring
to FIG. 35, the bulb portion 1720 is configured to reduce the average velocity
of a
flow of slurry moving from the entry segment 1436 through the bulb portion
1720 to
the transition segment 1730. In embodiments, the bulb portion 1720 is
configured to
reduce the average velocity of a flow of slurry moving from the entry segment
1436
through the bulb portion 1720 to the transition segment 1730 by at least
twenty
percent.
[00234] Referring to FIGS. 45-47, the bulb portion 1720 has an area of
expansion
1750 with a cross-sectional flow area that is greater than a cross-sectional
flow area
of an adjacent area upstream from the area of expansion relative to a flow
direction
1752 from the feed inlet 1424 toward the distribution outlet 1430 of the
distribution
conduit 1428. In embodiments, the bulb portion 1720 has a region 1752 with a
cross-sectional area in a plane perpendicular to the first flow axis 1735 that
is larger
than the cross-sectional area of the feed entry outlet 1711.
[00235] The shaped duct 1441 has a convex interior surface 1758 in confronting
relationship with the feed entry outlet 1711 of the entry segment 1436. The
bulb
portion 1720 has a generally radial guide channel 1460 disposed adjacent the
convex interior surface. The guide channel 1460 is configured to promote
radial flow
in a plane substantially perpendicular to the first feed flow axis 1735.
Referring to
FIG. 45, the convex interior surface 1758 is configured to define a central
restriction
1762 in the flow path which also helps increase the average velocity of the
slurry in
the radial guide channel 1760.
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[00236] The shaped duct 1441 can be configured such that a flow of slurry
moving
through a region adjacent the convex interior surface 1758 and adjacent at
least one
of the lateral sidewalls 1740, 1741 toward the distribution outlet 1430 has a
swirl
motion (Sm) from about zero to about 10, up to about 3 in other embodiments,
and
from about 0.5 to about 5 in still other embodiments. In embodiments, the flow
of
slurry moving through the region adjacent the convex interior surface 1758 and
adjacent at least one of the lateral sidewalls 1740, 1741 toward the
distribution outlet
1430 has a swirl angle (Sm) from about 0 to about 84 , and from about 10 to
about
80 in other embodiments.
[00237] Referring to FIGS. 34 and 35, the transition segment 1730 is in
fluid
communication with the bulb portion 1720. The illustrated transition segment
1730
extends along the longitudinal axis 50. The transition segment 1730 is
configured
such that its width, measured along the transverse axis 60, increases in the
direction
of flow from the bulb portion 1720 to the discharge outlet 1430. The
transition
segment 1730 extends along a second feed flow axis 1770, which is in non-
parallel
relationship with the first feed flow axis 1735.
[00238] In embodiments, the first feed flow axis 1735 is substantially
perpendicular
to the longitudinal axis 50. In embodiments, the first feed flow axis 1735 is
substantially parallel to the vertical axis 55, which is perpendicular to the
longitudinal
axis 50 and the transverse axis 60. In embodiments, the second feed flow axis
1770
is disposed at a respective feed angle 8 in a range up to about 135 with
respect to
the longitudinal axis 50.
[00239] In embodiments, the feed conduit 1422 includes a bifurcated connector
segment 1439 including first and second guide surfaces 1780, 1781. In
embodiments, the first and second guide surfaces 1781 can be respectively
adapted
to redirect first and second flows of slurry entering the feed conduit through
the first
and second inlets 1424, 1425 by a change in direction angle in a range up to
about
135 to an outlet flow direction.
[00240] Referring to FIGS. 41-43, each of the shaped ducts 1441, 1443 has a
concave exterior surface 1790, 1791 substantially complementary to the shape
of
the convex interior surface 1758 thereof and in underlying relationship
therewith.
Each concave exterior surface 1790, 1791 defines a recess 1794, 1795.
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[00241]
Referring to FIGS. 27, 35, and 36, a support insert 1801, 1802 is disposed
within each recess 1794, 1795 of the slurry distributor 1420. The support
inserts
1801, 1802 are disposed in underlying relationship to the respective convex
interior
surfaces of the shaped ducts 1441, 1443. The support inserts 1801, 1802 can be
made from any suitable material which will help support the slurry distributor
and
maintain a desired shape for the overlying interior convex surface. In the
illustrated
embodiment, the support inserts 1801, 1802 are substantially the same. In
other
embodiments, different support inserts can be used or in still further
embodiments
the inserts are not used.
[00242]
Referring to FIGS. 37-39, the rigid support insert 1801 includes a support
surface 1810 substantially conforming to the shape of the convex interior
surface of
the shaped duct. In embodiments, the shaped duct of the slurry distributor can
be
made from a sufficiently flexible material such that the convex interior
surface is
defined by support surface 1810 of the support insert 1801. In such cases, the
concave exterior surface of the shaped duct can be omitted.
[00243] The support insert 1801 includes a feed end 1820 and a distribution
end
1822. The support insert 1801 extends along a central support axis 1825. The
support insert 1801 is substantially symmetrical about the support axis 1825.
The
support insert 1801 is asymmetrical about a central axis 1830 perpendicular to
the
support axis 1825.
[00244]
Referring to FIG. 34, the distribution conduit 1428 extends generally along
the longitudinal axis 50 and includes an entry portion 1452 and a distribution
outlet
1430 in fluid communication with the entry portion 1452. The entry portion
1452 is in
fluid communication with the first and second feed inlets 1424, 1425 of the
feed
conduit 1422. The width of the distribution conduit 1428 increases from the
entry
portion 1452 to the distribution outlet 1430. In other embodiments, however,
the
width of the distribution conduit 1428 decreases or is constant from the entry
portion
1452 to the distribution outlet 1430.
[00245] The entry portion 1452 includes an entry opening 1453 having a
distribution entry width W5, along the transverse axis 60, and an entry height
H4,
along the vertical axis 55, wherein the distribution entry width W5 is less
than the
width W2 of the outlet opening 1481 of the distribution outlet 1430. In other
embodiments the distribution entry width W5 is greater than or equal to the
width W2
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of the outlet opening 1481 of the distribution outlet 1430. In embodiments,
the width-
to-height ratio of the outlet opening 1481 is about four or more.
[00246] In embodiments, at least one of the feed conduit 1422 and the
distribution
conduit 1428 includes a flow stabilization region adapted to reduce an average
feed
velocity of a flow of slurry entering the feed inlets 1424, 1425 and moving to
the
distribution outlet 1430 such that the flow of slurry discharges from the
distribution
outlet at an average discharge velocity that is at least twenty percent less
than the
average feed velocity.
[00247] FIGS. 44-53 progressively depict the interior geometry 1407 of a half
portion 1504 of the slurry distributor 1420 of FIG. 22. The slurry distributor
1420 of
FIG. 22 is similar in other respects to the slurry distributor 120 of FIG. 1
and the
slurry distributor 420 of FIG. 20.
[00248] Any suitable technique for making a slurry distributor constructed in
accordance with principles of the present disclosure can be used. For example,
in
embodiments where the slurry distributor is made from a flexible material,
such as
PVC or urethane, a multi-piece mold can be used. In some embodiments, the mold
piece areas are about 150% or less than the area of the molded slurry
distributor
through which the mold piece is being pulled during removal, about 125% or
less in
other embodiments, about 115% or less in still other embodiments, and about
110%
or less in yet other embodiments.
[00249] Referring to FIGS. 54 and 55, an embodiment of a multi-piece mold 550
suitable for use in making the slurry distributor 120 of FIG. 1 from a
flexible material,
such as PVC or urethane is shown. The illustrated multi-piece mold 550
includes
five mold segments 551, 552, 553, 554, 555. The mold segments 551, 552, 553,
554, 555 of the multi-piece mold 550 can be made from any suitable material,
such
as aluminum, for example.
[00250] In the
illustrated embodiment, the distributor conduit mold segment 551 is
configured to define the interior flow geometry of the distributor conduit
128. The
first and second shaped duct mold segments 552, 553 are configured to define
the
interior flow geometry of the first and the second shaped ducts 141, 143. The
first
and second entry mold segments 554, 555 define the interior flow geometry of
the
first entry segment 136 and the first feed inlet 124 and of the second entry
segment
137 and the second feed inlet 125, respectively. In other embodiments, the
multi-
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piece mold can include a different number of mold segments and/or the mold
segments can have different shapes and/or sizes.
[00251] Referring to FIG. 54, connecting bolts 571, 572, 573 can be inserted
through two or more mold segments to interlock and align the mold segments
551,
552, 553, 554, 555 such that a substantially continuous exterior surface 580
of the
multi-piece mold 550 is defined. In some embodiments, a distal portion 575 of
the
connecting bolts 571, 572, 573 includes an external thread that is configured
to
threadingly engage one of the mold segments 551, 552, 553, 554, 555 to
interconnect at least two of the mold segments 551, 552, 553, 554, 555. The
exterior surface 580 of the multi-piece mold 550 is configured to define the
interior
geometry of the molded slurry distributor 120 so that flashing at the joints
is reduced.
The connecting bolts 571, 572, 573 can be removed to disassemble the multi-
piece
mold 550 during removal of the mold 550 from the interior of the molded slurry
distributor 120.
[00252] The assembled multi-piece mold 550 is dipped into a solution of
flexible
material, such as PVC or urethane, such that the mold 550 is completely
submersed
in the solution. The mold 550 can then be removed from the dipped material. An
amount of the solution can adhere to the exterior surface 580 of the multi-
piece mold
550 which will constitute the molded slurry distributor 120 once the solution
changes
to a solid form. In embodiments, the multi-piece mold 550 can be used in any
suitable dipping process to form the molded piece.
[00253] By making the mold 550 out of multiple separate aluminum pieces ¨ in
the illustrated embodiment, five pieces ¨ that have been designed to fit
together to
provide the desired interior flow geometry, the mold segments 551, 552, 553,
554,
555 can be disengaged from each other and pulled out from the solution once it
has
begun to set but while it is still warm. At sufficiently-high temperatures,
the flexible
material is pliable enough to pull larger calculated areas of the aluminum
mold
pieces 551, 552, 553, 554, 555 through the smaller calculated areas of the
molded
slurry distributor 120 without tearing it. In some embodiments, the largest
mold
piece area is up to about 150% of the smallest area of the molded slurry
distributor
cavity area through which the particular mold piece traverses transversely
during the
removal process, up to about 125% in other embodiments, up to about 115% in
still
other embodiments, and up to about 110% in yet other embodiments.
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[00254] Referring to FIG. 56, an embodiment of a multi-piece mold 650 suitable
for
use in making the slurry distributor 320 of FIG. 6 from a flexible material,
such as
PVC or urethane is shown. The illustrated multi-piece mold 650 includes five
mold
segments 651, 652, 653, 654, 655. The mold segments 651, 652, 653, 654, 655 of
the multi-piece mold 550 can be made from any suitable material, such as
aluminum,
for example. The mold segments 651, 652, 653, 654, 655 are shown in a
disassembled condition in FIG. 56.
[00255] Connecting bolts can be used to removably connect the mold segments
651, 652, 653, 654, 655 together to assemble the mold 650 such that a
substantially
continuous exterior surface of the multi-piece mold 650 is defined. The
exterior
surface of the multi-piece mold 650 defines the internal flow geometry of the
slurry
distributor 220 of FIG. 6. The mold 650 can be similar in construction to the
mold
550 of FIGS. 54 and 55 in that each piece of the mold 650 of FIG. 56 is
constructed
such that its area is within a predetermined amount of the smallest area of
the
molded slurry distributor 220 through which the mold piece must traverse when
it is
being removed (e.g., up to about 150% of the smallest area of the molded
slurry
distributor cavity area through which the particular mold piece traverses
transversely
during the removal process in some embodiments, up to about 125% in other
embodiments, up to about 115% in still other embodiments, and up to about 110%
in
yet other embodiments).
[00256] Referring to FIGS. 57 and 58, an embodiment of a mold 750 for use in
making one of the pieces 221, 223 of the two-piece slurry distributor 220 of
FIG. 4 is
shown. Referring to FIG. 57, mounting bore-defining elements 752 can be
included
to define mounting bores in the piece of the two-piece slurry distributor 220
of FIG. 4
being made to facilitate its connection with the other piece.
[00257] Referring to FIGS. 57 and 58, the mold 750 includes a mold surface 754
projecting from a bottom surface 756 of the mold 750. A boundary wall 756
extends
along the vertical axis and defines the depth of the mold. The mold surface
754 is
disposed within the boundary wall 756. The boundary wall 756 is configured to
allow
the volume of a cavity 758 defined within the boundary wall to be filled with
molten
mold material such that the mold surface 754 is immersed. The mold surface 754
is
configured to be a negative image of the interior flow geometry defined by the
particular piece of the two-piece distributor being molded.
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[00258] In use, the cavity 758 of the mold 750 can be filled with a molten
material
such that the mold surface is immersed and the cavity 758 is filled with
molten
material. The molten material can be allowed to cool and removed from the mold
750. Another mold can be used to form the mating piece of the slurry
distributor 220
of FIG. 4.
[00259] Referring to FIG. 59, an embodiment of a gypsum slurry mixing and
dispensing assembly 810 includes a gypsum slurry mixer 912 in fluid
communication
with a slurry distributor 820 similar to the slurry distributor 320 shown in
FIG. 6. The
gypsum slurry mixer 812 is adapted to agitate water and calcined gypsum to
form an
aqueous calcined gypsum slurry. Both the water and the calcined gypsum can be
supplied to the mixer 812 via one or more inlets as is known in the art. Any
suitable
mixer (e.g., a pin mixer) can be used with the slurry distributor.
[00260] The slurry distributor 820 is in fluid communication with the gypsum
slurry
mixer 812. The slurry distributor 820 includes a first feed inlet 824 adapted
to
receive a first flow of aqueous calcined gypsum slurry from the gypsum slurry
mixer
812 moving in a first feed direction 890, a second feed inlet 825 adapted to
receive a
second flow of aqueous calcined gypsum slurry from the gypsum slurry mixer 812
moving in a second feed direction 891, and a distribution outlet 830 in fluid
communication with both the first and the second feed inlets 824, 825 and
adapted
such that the first and second flows of aqueous calcined gypsum slurry
discharge
from the slurry distributor 820 through the distribution outlet 830
substantially along a
machine direction 50.
[00261] The slurry distributor 820 includes a feed conduit 822 in fluid
communication with a distribution conduit 828. The feed conduit includes the
first
feed inlet 824 and the second feed inlet 825 disposed in spaced relationship
to the
first feed inlet 824, which are both disposed at a feed angle 0 of about 60
with
respect to the machine direction 50. The feed conduit 822 includes structure
therein
adapted to receive the first and second flows of slurry moving in the first
and second
feed flow direction 890, 891 and redirect the slurry flow direction by a
change in
direction angle a (see FIG. 9) such that the first and second flows of slurry
are
conveyed into the distribution conduit 828 moving substantially in the outlet
flow
direction 892, which is substantially aligned with the machine direction 50.
The first
and second feed inlets 824, 825 each has an opening with a cross-sectional
area,
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and the entry portion 852 of the distribution conduit 828 has an opening with
a cross-
sectional area which is greater than the sum of the cross-sectional areas of
the
openings of the first and second feed inlets 824, 825.
[00262] The distribution conduit 828 extends generally along the longitudinal
axis
or machine direction 50, which is substantially perpendicular to a transverse
axis 60.
The distribution conduit 828 includes an entry portion 852 and the
distribution outlet
830. The entry portion 852 is in fluid communication with the first and second
feed
inlets 824, 825 of the feed conduit 822 such that the entry portion 852 is
adapted to
receive both the first and the second flows of aqueous calcined gypsum slurry
therefrom. The distribution outlet 830 is in fluid communication with the
entry portion
852. The distribution outlet 830 of the distribution conduit 828 extends a
predetermined distance along the transverse axis 60 to facilitate the
discharge of the
combined first and second flows of aqueous calcined gypsum slurry in the cross-
machine direction or along the transverse axis 60. The slurry distributor 820
can be
similar in other respects to the slurry distributor 320 of FIG. 6.
[00263] A delivery conduit 814 is disposed between and in fluid communication
with the gypsum slurry mixer 812 and the slurry distributor 820. The delivery
conduit
814 includes a main delivery trunk 815, a first delivery branch 817 in fluid
communication with the first feed inlet 824 of the slurry distributor 820, and
a second
delivery branch 818 in fluid communication with the second feed inlet 825 of
the
slurry distributor 820. The main delivery trunk 815 is in fluid communication
with
both the first and second delivery branches 817, 818. In other embodiments,
the first
and second delivery branches 817, 818 can be in independent fluid
communication
with the gypsum slurry mixer 812.
[00264] The delivery conduit 814 can be made from any suitable material and
can
have different shapes. In some embodiments, the delivery conduit 814 can
comprise
a flexible conduit.
[00265] An aqueous foam supply conduit 821 can be in fluid communication with
at
least one of the gypsum slurry mixer 812 and the delivery conduit 814. An
aqueous
foam from a source can be added to the constituent materials through the foam
supply conduit 821 at any suitable location downstream of the mixer 812 and/or
in
the mixer 812 itself to form a foamed gypsum slurry that is provided to the
slurry
distributor 220. In the illustrated embodiment, the foam supply conduit 821 is
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disposed downstream of the gypsum slurry mixer 812. In the illustrated
embodiment, the aqueous foam supply conduit 821 has a manifold-type
arrangement for supplying foam to an injection ring or block associated with
the
delivery conduit 814 as described in U.S. Patent No. 6,874,930, for example.
[00266] In other embodiments, one or more foam supply conduits can be provided
that are in fluid communication with the mixer 812. In yet other embodiments,
the
aqueous foam supply conduit(s) can be in fluid communication with the gypsum
slurry mixer alone. As will be appreciated by those skilled in the art, the
means for
introducing aqueous foam into the gypsum slurry in the gypsum slurry mixing
and
dispensing assembly 810, including its relative location in the assembly, can
be
varied and/or optimized to provide a uniform dispersion of aqueous foam in the
gypsum slurry to produce board that is fit for its intended purpose.
[00267] Any suitable foaming agent can be used. Preferably, the aqueous foam
is
produced in a continuous manner in which a stream of the mix of foaming agent
and
water is directed to a foam generator, and a stream of the resultant aqueous
foam
leaves the generator and is directed to and mixed with the calcined gypsum
slurry.
Some examples of suitable foaming agents are described in U.S. Patent Nos.
5,683,635 and 5,643,510, for example.
[00268] When the foamed gypsum slurry sets and is dried, the foam dispersed in
the slurry produces air voids therein which act to lower the overall density
of the
wallboard. The amount of foam and/or amount of air in the foam can be varied
to
adjust the dry board density such that the resulting wallboard product is
within a
desired weight range.
[00269] One or more flow-modifying elements 823 can be associated with the
delivery conduit 814 and adapted to control the first and the second flows of
aqueous
calcined gypsum slurry from the gypsum slurry mixer 812. The flow-modifying
element(s) 823 can be used to control an operating characteristic of the first
and
second flows of aqueous calcined gypsum slurry. In the illustrated embodiment
of
FIG. 59, the flow-modifying element(s) 823 is associated with the main
delivery trunk
815. Examples of suitable flow-modifying elements include volume restrictors,
pressure reducers, constrictor valves, canisters, etc., including those
described in
U.S. Pat. Nos. 6,494,609; 6,874,930; 7,007,914; and 7,296,919, for example.
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[00270] The main delivery trunk 815 can be joined to the first and second
delivery
branches 817, 818 via a suitable Y-shaped flow splitter 819. The flow splitter
819 is
disposed between the main delivery trunk 815 and the first delivery branch 817
and
between the main delivery trunk 815 and the second delivery branch 818. In
some
embodiments, the flow splitter 819 can be adapted to help split the first and
second
flows of gypsum slurry such that they are substantially equal. In other
embodiments,
additional components can be added to help regulate the first and second flows
of
slurry.
[00271] In use, an aqueous calcined gypsum slurry is discharged from the mixer
812. The aqueous calcined gypsum slurry from the mixer 812 is split in the
flow
splitter 819 into the first flow of aqueous calcined gypsum slurry and the
second flow
of aqueous calcined gypsum slurry. The aqueous calcined gypsum slurry from the
mixer 812 can be split such that the first and second flows of aqueous
calcined
gypsum slurry are substantially balanced.
[00272] Referring to FIG. 60, another embodiment of a gypsum slurry mixing and
dispensing assembly 910 is shown. The gypsum slurry mixing and dispensing
assembly 910 includes a gypsum slurry mixer 912 in fluid communication with a
slurry distributor 920. The gypsum slurry mixer 912 is adapted to agitate
water and
calcined gypsum to form an aqueous calcined gypsum slurry. The slurry
distributor
920 can be similar in construction and function to the slurry distributor 320
of FIG. 6.
[00273] A delivery conduit 914 is disposed between and in fluid communication
with the gypsum slurry mixer 912 and the slurry distributor 920. The delivery
conduit
914 includes a main delivery trunk 915, a first delivery branch 917 in fluid
communication with the first feed inlet 924 of the slurry distributor 920, and
a second
delivery branch 918 in fluid communication with the second feed inlet 925 of
the
slurry distributor 920.
[00274] The main delivery trunk 915 is disposed between and in fluid
communication with the gypsum slurry mixer 912 and both the first and the
second
delivery branches 917, 918. An aqueous foam supply conduit 921 can be in fluid
communication with at least one of the gypsum slurry mixer 912 and the
delivery
conduit 914. In the illustrated embodiment, the aqueous foam supply conduit
921 is
associated with the main delivery trunk 915 of the delivery conduit 914.
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[00275] The first delivery branch 917 is disposed between and in fluid
communication with the gypsum slurry mixer 912 and the first feed inlet 924 of
the
slurry distributor 920. At least one first flow-modifying element 923 is
associated
with the first delivery branch 917 and is adapted to control the first flow of
aqueous
calcined gypsum slurry from the gypsum slurry mixer 912.
[00276] The second delivery branch 918 is disposed between and in fluid
communication with the gypsum slurry mixer 912 and the second feed inlet 925
of
the slurry distributor 920. At least one second flow-modifying element 927 is
associated with the second delivery branch 918 and is adapted to control the
second
flow of aqueous calcined gypsum slurry from the gypsum slurry mixer 912.
[00277] The first and second flow-modifying elements 923, 927 can be operated
to
control an operating characteristic of the first and second flows of aqueous
calcined
gypsum slurry. The first and second flow-modifying elements 923, 927 can be
independently operable. In some embodiments, the first and second flow-
modifying
elements 923, 927 can be actuated to deliver first and second flows of
slurries that
alternate between a relatively slower and relatively faster average velocity
in
opposing fashion such that at a given time the first slurry has an average
velocity
that is faster than that of the second flow of slurry and at another point in
time the
first slurry has an average velocity that is slower than that of the second
flow of
slurry.
[00278] As one of ordinary skill in the art will appreciate, one or both of
the webs of
cover sheet material can be pre-treated with a very thin relatively denser
layer of
gypsum slurry (relative to the gypsum slurry comprising the core), often
referred to
as a skim coat in the art, and/or hard edges, if desired. To that end, the
mixer 912
includes a first auxiliary conduit 929 that is adapted to deposit a stream of
dense
aqueous calcined gypsum slurry that is relatively denser than the first and
second
flows of aqueous calcined gypsum slurry delivered to the slurry distributor
(i.e., a
"face skim coat/hard edge stream"). The first auxiliary conduit 929 can
deposit the
face skim coat/hard edge stream upon a moving web of cover sheet material
upstream of a skim coat roller 931 that is adapted to apply a skim coat layer
to the
moving web of cover sheet material and to define hard edges at the periphery
of the
moving web by virtue of the width of the roller 931 being less than the width
of the
moving web as is known in the art. Hard edges can be formed from the same
dense
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slurry that forms the thin dense layer by directing portions of the dense
slurry around
the ends of the roller used to apply the dense layer to the web.
[00279] The mixer 912 can also include a second auxiliary conduit 933 adapted
to
deposit a stream of dense aqueous calcined gypsum slurry that is relatively
denser
than the first and second flows of aqueous calcined gypsum slurry delivered to
the
slurry distributor (i.e., a "back skim coat stream"). The second auxiliary
conduit 933
can deposit the back skim coat stream upon a second moving web of cover sheet
material upstream (in the direction of movement of the second web) of a skim
coat
roller 937 that is adapted to apply a skim coat layer to the second moving web
of
cover sheet material as is known in the art (see FIG. 61 also).
[00280] In other embodiments, separate auxiliary conduits can be connected to
the
mixer to deliver one or more separate edge streams to the moving web of cover
sheet material. Other suitable equipment (such as auxiliary mixers) can be
provided
in the auxiliary conduits to help make the slurry therein denser, such as by
mechanically breaking up foam in the slurry and/or by chemically breaking down
the
foam through use of a suitable de-foaming agent.
[00281] In yet other embodiments, first and second delivery branches can each
include a foam supply conduit therein which are respectively adapted to
independently introduce aqueous foam into the first and second flows of
aqueous
calcined gypsum slurry delivered to the slurry distributor. In still other
embodiments,
a plurality of mixers can be provided to provide independent streams of slurry
to the
first and second feed inlets of a slurry distributor constructed in accordance
with
principles of the present disclosure. It will be appreciated that other
embodiments
are possible.
[00282] The gypsum slurry mixing and dispensing assembly 910 of FIG. 60 can be
similar in other respects to the gypsum slurry mixing and dispensing assembly
810 of
FIG. 59. It is further contemplated that other slurry distributors constructed
in
accordance with principles of the present disclosure can be used in other
embodiments of a cementitious slurry mixing and dispensing assembly as
described
herein.
[00283] Referring to FIG. 61, an exemplary embodiment of a wet end 1011 of a
gypsum wallboard manufacturing line is shown. The wet end 1011 includes a
gypsum slurry mixing and dispensing assembly 1010 having a gypsum slurry mixer
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1012 in fluid communication with a slurry distributor 1020 similar in
construction and
function to the slurry distributor 320 of FIG. 6, a hard edge/face skim coat
roller 1031
disposed upstream of the slurry distributor 1020 and supported over a forming
table
1038 such that a first moving web 1039 of cover sheet material is disposed
therebetween, a back skim coat roller 1037 disposed over a support element
1041
such that a second moving web 1043 of cover sheet material is disposed
therebetween, and a forming station 1045 adapted to shape the preform into a
desired thickness. The skim coat rollers 1031, 1037, the forming table 1038,
the
support element 1041, and the forming station 1045 can all comprise
conventional
equipment suitable for their intended purposes as is known in the art. The wet
end
1011 can be equipped with other conventional equipment as is known in the art.
[00284] In
another aspect of the present disclosure, a slurry distributor constructed
in accordance with principles of the present disclosure can be used in a
variety of
manufacturing processes. For example, in one embodiment, a slurry distribution
system can be used in a method of preparing a gypsum product. A slurry
distributor
can be used to distribute an aqueous calcined gypsum slurry upon the first
advancing web 1039.
[00285] Water and calcined gypsum can be mixed in the mixer 1012 to form the
first and second flows 1047, 1048 of aqueous calcined gypsum slurry. In some
embodiments, the water and calcined gypsum can be continuously added to the
mixer in a water-to-calcined gypsum ratio from about 0.5 to about 1.3, and in
other
embodiments of about 0.75 or less.
[00286] Gypsum board products are typically formed "face down" such that the
advancing web 1039 serves as the "face" cover sheet of the finished board. A
face
skim coat/hard edge stream 1049 (a layer of denser aqueous calcined gypsum
slurry
relative to at least one of the first and second flows of aqueous calcined
gypsum
slurry) can be applied to the first moving web 1039 upstream of the hard
edge/face
skim coat roller 1031, relative to the machine direction 1092, to apply a skim
coat
layer to the first web 1039 and to define hard edges of the board.
[00287] The first flow 1047 and the second flow 1048 of aqueous calcined
gypsum
slurry are respectively passed through the first feed inlet 1024 and the
second feed
inlet 1025 of the slurry distributor 1020. The first and second flows 1047,
1048 of
aqueous calcined gypsum slurry are combined in the slurry distributor 1020.
The
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first and second flows 1047, 1048 of aqueous calcined gypsum slurry move along
a
flow path through the slurry distributor 1020 in the manner of a streamline
flow,
undergoing minimal or substantially no air-liquid slurry phase separation and
substantially without undergoing a vortex flow path.
[00288] The first moving web 1039 moves along the longitudinal axis 50. The
first
flow 1047 of aqueous calcined gypsum slurry passes through the first feed
inlet
1024, and the second flow 1048 of aqueous calcined gypsum slurry passes
through
the second feed inlet 1025. The distribution conduit 1028 is positioned such
that it
extends along the longitudinal axis 50 which substantially coincides with the
machine
direction 1092 along which the first web 1039 of cover sheet material moves.
Preferably, the central midpoint of the distribution outlet 1030 (taken along
the
transverse axis / cross-machine direction 60) substantially coincides with the
central
midpoint of the first moving cover sheet 1039. The first and second flows
1047,
1048 of aqueous calcined gypsum slurry combine in the slurry distributor 1020
such
that the combined first and second flows 1051 of aqueous calcined gypsum
slurry
pass through the distribution outlet 1030 in a distribution direction 1093
generally
along the machine direction 1092.
[00289] In some embodiments, the distribution conduit 1028 is positioned such
that
it is substantially parallel to the plane defines by the longitudinal axis 50
and the
transverse axis 60 of the first web 1039 moving along the forming table. In
other
embodiments, the entry portion of the distribution conduit can be disposed
vertically
lower or higher than the distribution outlet 1030 relative to the first web
1039.
[00290] The combined first and second flows 1051 of aqueous calcined gypsum
slurry are discharged from the slurry distributor 1020 upon the first moving
web
1039. The face skim coat/hard edge stream 1049 can be deposited from the mixer
1012 at a point upstream, relative to the direction of movement of the first
moving
web 1039 in the machine direction 1092, of where the first and second flows
1047,
1048 of aqueous calcined gypsum slurry are discharged from the slurry
distributor
1020 upon the first moving web 1039. The combined first and second flows 1047,
1048 of aqueous calcined gypsum slurry can be discharged from the slurry
distributor with a reduced momentum per unit width along the cross-machine
direction relative to a conventional boot design to help prevent "washout" of
the face
skim coat/hard edge stream 1049 deposited on the first moving web 1039 (i.e.,
the
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situation where a portion of the deposited skim coat layer is displaced from
its
position upon the moving web 339 in response to the impact of the slurry being
deposited upon it).
[00291] The first and second flows 1047, 1048 of aqueous calcined gypsum
slurry
respectively passed through the first and second feed inlets 1024, 1025 of the
slurry
distributor 1020 can be selectively controlled with at least one flow-
modifying
element 1023. For example, in some embodiments, the first and second flows
1047,
1048 of aqueous calcined gypsum slurry are selectively controlled such that
the
average velocity of the first flow 1047 of aqueous calcined gypsum slurry
passing
through the first feed inlet 1024 and the average velocity of the second flow
1048 of
aqueous calcined gypsum slurry passing through the second feed inlet 1025 are
substantially the same.
[00292] In embodiments, the first flow 1047 of aqueous calcined gypsum slurry
is
passed at an average first feed velocity through the first feed inlet 1024 of
the slurry
distributor 1020. The second flow 1048 of aqueous calcined gypsum slurry is
passed at an average second feed velocity through the second feed inlet 1025
of the
slurry distributor 1020. The second feed inlet 1025 is in spaced relationship
to the
first feed inlet 1024. The first and second flows 1051 of aqueous calcined
gypsum
slurry are combined in the slurry distributor 1020. The combined first and
second
flows 1051 of aqueous calcined gypsum slurry are discharged at an average
discharge velocity from a distribution outlet 1030 of the slurry distributor
1020 upon
the web 1039 of cover sheet material moving along a machine direction 1092.
The
average discharge velocity is less than the average first feed velocity and
the
average second feed velocity.
[00293] In some embodiments, the average discharge velocity is less than about
90% of the average first feed velocity and the average second feed velocity.
In
some embodiments, the average discharge velocity is less than about 80% of the
average first feed velocity and the average second feed velocity.
[00294] The combined first and second flows 1051 of aqueous calcined gypsum
slurry are discharged from the slurry distributor 1020 through the
distribution outlet
1030. The opening of the distribution outlet 1030 has a width extending along
the
transverse axis 60 and sized such that the ratio of the width of the first
moving web
1039 of cover sheet material to the width of the opening of the distribution
outlet
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1030 is within a range including and between about 1:1 and about 6:1. In some
embodiments, the ratio of the average velocity of the combined first and
second
flows 1051 of aqueous calcined gypsum slurry discharging from the slurry
distributor
1020 to the velocity of the moving web 1039 of cover sheet material moving
along
the machine direction 1092 can be about 2:1 or less in some embodiments, and
from
about 1:1 to about 2:1 in other embodiments.
[00295] The combined first and second flows 1051 of aqueous calcined gypsum
slurry discharging from the slurry distributor 1020 form a spread pattern upon
the
moving web 1039. At least one of the size and shape of the distribution outlet
1030
can be adjusted, which in turn can change the spread pattern.
[00296] Thus, slurry is fed into both feed inlets 1024, 1025 of the feed
conduit
1022 and then exits through the distribution outlet 1030 with an adjustable
gap. A
converging portion 1082 can provide a slight increase in the slurry velocity
so as to
reduce unwanted exit effects and thereby further improve flow stability at the
free
surface. Side-to-side flow variation and/or any local variations can be
reduced by
performing cross-machine (CD) profiling control at the discharge outlet 1030
using
the profiling system. This distribution system can help prevent air-liquid
slurry
separation in the slurry resulting in a more uniform and consistent material
delivered
to the forming table 1038.
[00297] A back skim coat stream 1053 (a layer of denser aqueous calcined
gypsum slurry relative to at least one of the first and second flows 1047,
1048 of
aqueous calcined gypsum slurry) can be applied to the second moving web 1043.
The back skim coat stream 1053 can be deposited from the mixer 1012 at a point
upstream, relative to the direction of movement of the second moving web 1043,
of
the back skim coat roller 1037.
[00298] In other embodiments, the average velocity of the first and second
flows
1047, 1048 of aqueous calcined gypsum slurry are varied. In some embodiments,
the slurry velocities at the feed inlets 1024, 1025 of the feed conduit 1022
can
oscillate periodically between relatively higher and lower average velocities
(at one
point in time one inlet has a higher velocity than the other inlet, and then
at a
predetermined point in time vice versa) to help reduce the chance of buildup
within
the geometry itself.
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[00299] In embodiments, the first flow 1047 of aqueous calcined gypsum slurry
passing through the first feed inlet 1024 has a shear rate that is lower than
the shear
rate of the combined first and second flows 1051 discharging from the
distribution
outlet 1030, and the second flow 1048 of aqueous calcined gypsum slurry
passing
through the second feed inlet 1025 has a shear rate that is lower than the
shear rate
of the combined first and second flows 1051 discharging from the distribution
outlet
1030. In embodiments, the shear rate of the combined first and second flows
1051
discharging from the distribution outlet 1030 can be greater than about 150%
of the
shear rate of the first flow 1047 of aqueous calcined gypsum slurry passing
through
the first feed inlet 1024 and/or the second flow 1048 of aqueous calcined
gypsum
slurry passing through the second feed inlet 1025, greater than about 175% in
still
other embodiments, and about double or greater in yet other embodiments. It
should
be understood that the viscosity of the first and second flows 1047, 1048 of
aqueous
calcined gypsum slurry and the combined first and second flows 1051 can be
inversely related to the shear rate present at a given location such that as
the shear
rate goes up, the viscosity decreases.
[00300] In embodiments, the first flow 1047 of aqueous calcined gypsum slurry
passing through the first feed inlet 1024 has a shear stress that is lower
than the
shear stress of the combined first and second flows 1051 discharging from the
distribution outlet 1030, and the second flow 1048 of aqueous calcined gypsum
slurry passing through the second feed inlet 1025 has a shear stress that is
lower
than the shear stress of the combined first and second flows 1051 discharging
from
the distribution outlet 1030. In embodiments, the shear stress of the combined
first
and second flows 1051 discharging from the distribution outlet 1030 can be
greater
than about 110% of the shear rate of the first flow 1047 of aqueous calcined
gypsum
slurry passing through the first feed inlet 1024 and/or the second flow 1048
of
aqueous calcined gypsum slurry passing through the second feed inlet 1025.
[00301] In embodiments, the first flow 1047 of aqueous calcined gypsum slurry
passing through the first feed inlet 1024 has a Reynolds number that is higher
than
the Reynolds number of the combined first and second flows 1051 discharging
from
the distribution outlet 1030, and the second flow 1048 of aqueous calcined
gypsum
slurry passing through the second feed inlet 1025 has a Reynolds number that
is
higher than the Reynolds number of the combined first and second flows 1051
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discharging from the distribution outlet 1030. In embodiments, the Reynolds
number
of the combined first and second flows 1051 discharging from the distribution
outlet
1030 can be less than about 90% of the Reynolds number of the first flow 1047
of
aqueous calcined gypsum slurry passing through the first feed inlet 1024
and/or the
second flow 1048 of aqueous calcined gypsum slurry passing through the second
feed inlet 1025, less than about 80% in still other embodiments, and less than
about
70% in still other embodiments.
[00302] Referring to FIGS. 62 and 63, an embodiment of a Y-shaped flow
splitter
1100 suitable for use in a gypsum slurry mixing and dispensing assembly
constructed in accordance with principles of the present disclosure is shown.
The
flow splitter 1100 can be placed in fluid communication with a gypsum slurry
mixer
and a slurry distributor such that the flow splitter 1100 receives a single
flow of
aqueous calcined gypsum slurry from the mixer and discharges two separate
flows
of aqueous calcined gypsum slurry therefrom to the first and second feed
inlets of
the slurry distributor. One or more flow-modifying elements can be disposed
between the mixer and the flow splitter 1100 and/or between one or both of the
delivery branches leading between the splitter 1100 and the associated slurry
distributor.
[00303] The flow splitter 1100 has a substantially circular inlet 1102
disposed in a
main branch 1103 adapted to receive a single flow of slurry and a pair of
substantially circular outlets 1104, 1106 disposed respectively in first and
second
outlet branches 1105, 1107 that allow two flows of slurry to discharge from
the
splitter 1100. The cross-sectional areas of the openings of the inlet 1102 and
the
outlets 1104, 1106 can vary depending on the desired flow velocity. In
embodiments
where the cross-sectional areas of the openings of outlet 1104, 1106 are each
substantially equal to cross-sectional area of the opening of the inlet 1102,
the flow
velocity of the slurry discharging from each outlet 1104, 1106 can be reduced
to
about 50% of the velocity of the single flow of slurry entering the inlet 1102
where the
volumetric flow rate through the inlet 1102 and both outlets 1104, 1106 is
substantially the same.
[00304] In some embodiments, the diameter of the outlets 1104, 1106 can be
made smaller than the diameter of the inlet 1102 in order to maintain a
relatively high
flow velocity throughout the splitter 1100. In embodiments where the cross-
sectional
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areas of the openings of the outlets 1104, 1106 are each smaller than the
cross-
sectional area of the opening of the inlet 1102, the flow velocity can be
maintained in
the outlets 1104, 1106 or at least reduced to a lesser extent than if the
outlets 1104,
1106 and the inlet 1102 all have substantially equal cross-sectional areas.
For
example, in some embodiments, the flow splitter 1100 has the inlet 1102 has an
inner diameter (ID1) of about 3 inches, and each outlet 1104, 1106 has an 102
of
about 2.5 inches (though other inlet and outlet diameters can be used in other
embodiments). In an embodiment with these dimensions at a line speed of 350
fpm,
the smaller diameter of the outlets 1104, 1106 causes the flow velocity in
each outlet
to be reduced by about 28% of the flow velocity of the single flow of slurry
at the inlet
1102.
[00305] The flow splitter 1100 can includes a central contoured portion 1114
and a
junction 1120 between the first and second outlet branches 1105, 1107. The
central
contoured portion 1114 creates a restriction 1108 in the central interior
region of the
flow splitter 1100 upstream of the junction 1120 that helps promote flow to
the outer
edges 1110, 1112 of the splitter to reduce the occurrence of slurry buildup at
the
junction 1120. The shape of the central contoured portion 1114 results in
guide
channels 1111, 1113 adjacent the outer edges 1110, 1112 of the flow splitter
1100.
The restriction 1108 in the central contoured portion 1114 has a smaller
height H2
than the height H3 of the guide channels 1111, 1113. The guide channels 1111,
1113 have a cross-sectional area that is larger than the cross-sectional area
of the
central restriction 1108. As a result, the flowing slurry encounters less flow
resistance through the guide channels 1111, 1113 than through the central
restriction 1108, and flow is directed toward the outer edges of the splitter
junction
1120.
[00306] The junction 1120 establishes the openings to the first and second
outlet
branches 1105, 1107. The junction 1120 is made up of a planar wall surface
1123
that is substantially perpendicular to an inlet flow direction 1125.
100307] Referring to FIG. 64, in some embodiments, an automatic device 1150
for
squeezing the splitter 1100 at adjustable and regular time intervals can be
provided
to prevent solids building up inside the splitter 1100. In some embodiments,
the
squeezing apparatus 1150 can include a pair of plates 1152, 1154 disposed on
opposing sides 1142, 1143 of the central contoured portion 1114. The plates
1152,
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1154 are movable relative to each other by a suitable actuator 1160. The
actuator
1160 can be operated either automatically or selectively to move the plates
1152,
1154 together relative to each other to apply a compressive force upon the
splitter
1100 at the central contoured portion 1114 and the junction 1120.
[00308] When the squeezing apparatus 1150 squeezes the flow splitter, the
squeezing action applies compressive force to the flow splitter 1100, which
flexes
inwardly in response. This compressive force can help prevent buildup of
solids
inside the splitter 1100 which may disrupt the substantially equally split
flow to the
slurry distribution through the outlets 1104, 1106. In some embodiments, the
squeezing apparatus 1150 is designed to automatically pulse through the use of
a
programmable controller operably arranged with the actuators. The time
duration of
the application of the compressive force by the squeezing apparatus 1150
and/or the
interval between pulses can be adjusted. Furthermore, the stroke length that
the
plates 1152, 1154 travel with respect to each other in a compressive direction
can be
adjusted.
[00309] In an embodiment, a method of preparing a cementitious product can be
performed using a slurry distributor constructed according to principles of
the present
disclosure. A flow of aqueous cementitious slurry is discharged from a mixer.
A flow
of aqueous cementitious slurry is passed at an average feed velocity through a
feed
inlet of a slurry distributor along a first feed flow axis. The flow of
aqueous
cementitious slurry is passed into a bulb portion of the slurry distributor.
The bulb
portion has an area of expansion with a cross-sectional flow area that is
greater than
a cross-sectional flow area of an adjacent area upstream from the area of
expansion
relative to a flow direction from the feed inlet. The bulb portion is
configured to
reduce the average velocity of the flow of aqueous cementitious slurry moving
from
the feed inlet through the bulb portion. The shaped duct has a convex interior
surface in confronting relationship with first feed flow axis such that the
flow of
aqueous cementitious slurry moves in radial flow in a plane substantially
perpendicular to the first feed flow axis. The flow of aqueous cementitious
slurry is
passed into a transition segment extending along a second feed flow axis,
which is in
non-parallel relationship with the first feed flow axis.
[00310] The flow of aqueous cementitious slurry is passed into a distribution
conduit. The distribution conduit includes a distribution outlet extending a
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predetermined distance along a transverse axis, which is substantially
perpendicular
to the longitudinal axis.
[00311] In embodiments, the flow of slurry moving through a region adjacent
the
convex interior surface and adjacent at least one of the lateral sidewalls
toward the
distribution outlet has a swirl motion (Sm) from about zero to about 10, and
from
about 0.5 to about 5 in other embodiments. In embodiments, the flow of slurry
moving through the region adjacent the convex interior surface and adjacent at
least
one of the lateral sidewalls toward the distribution outlet has a swirl angle
(Sm) from
about 00 to about 84 .
[00312] In embodiments, the flow of aqueous cementitious slurry is passed
through a flow stabilization region adapted to reduce an average feed velocity
of the
flow of aqueous cementitious slurry entering the feed inlet and moving to the
distribution outlet. The flow of aqueous cementitious slurry is discharged
from the
distribution outlet at an average discharge velocity that is at least twenty
percent less
than the average feed velocity.
[00313] In another embodiment, a method of preparing a cementitious product
includes discharging a flow of aqueous cementitious slurry from a mixer. The
flow of
aqueous cementitious slurry is passed through an entry portion of a
distribution
conduit of a slurry distributor. The flow of aqueous cementitious slurry is
discharged
from a distribution outlet of the slurry distributor upon a web of cover sheet
material
moving along a machine direction. A wiper blade is reciprocally moved over a
clearing path along a bottom surface of the distribution conduit between a
first
position and a second position to clear aqueous cementitious slurry therefrom.
The
clearing path is disposed adjacent the distribution outlet.
[00314] In embodiments, the distribution conduit extends generally along a
longitudinal axis between the entry portion and the distribution outlet. The
wiper
blade reciprocally moves longitudinally along the clearing path.
[00315] In embodiments, the wiper blade moves in a clearing direction from the
first position to the second position over a wiping stroke, and the wiper
blade moves
in an opposing, return direction from the second position to the first
position over a
return stroke. The wiper blade reciprocally moves such that the time to move
over
the wiping stroke is substantially the same as the time to move over the
return
stroke.
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[00316] In embodiments, the wiper blade moves in a clearing direction from the
first position to the second position over a wiping stroke, and the wiper
blade moves
in an opposing, return direction from the second position to the first
position over a
return stroke. The wiper blade reciprocally moves between the first position
and the
second position in a cycle having a sweep period. The sweep period includes a
wiping portion comprising the time to move over the wiping stroke, a returning
portion comprising the time to move over the return stroke, and an
accumulation
delay portion comprising a predetermined period of time in which the wiper
blade
remains in the first position. In embodiments, the wiping portion is
substantially the
same as the returning portion. In embodiments, the accumulation delay portion
is
adjustable.
[00317] In still another embodiment, a method of preparing a cementitious
product
includes discharging a flow of aqueous cementitious slurry from a mixer. The
flow of
aqueous cementitious slurry is passed through an entry portion of a
distribution
conduit of a slurry distributor. The flow of aqueous cementitious slurry is
discharged
from an outlet opening of a distribution outlet of the slurry distributor upon
a web of
cover sheet material moving along a machine direction. The distribution outlet
extends a predetermined distance along a transverse axis, which is
substantially
perpendicular to the longitudinal axis. The outlet opening has a width, along
the
transverse axis, and a height, along a vertical axis mutually perpendicular to
the
longitudinal axis and the transverse axis. A portion of the distribution
conduit
adjacent the distribution outlet is compressively engaged to vary the shape
and/or
size of the outlet opening. In embodiments, the distribution conduit is
compressively
engaged by a profiling mechanism such that the flow of aqueous cementitious
slurry
is discharged from the outlet opening with an increased spread angle relative
to the
machine direction.
[00318] In embodiments, the distribution conduit is compressively engaged by a
profiling mechanism having a profiling member in contacting relationship with
the
distribution conduit. The profiling member is movable over a range of travel
such
that the profiling member is in a range of positions over which the profiling
member is
in increasing compressive engagement with the distribution conduit. In
embodiments the method includes moving the profiling member along the vertical
axis to adjust the size and/or shape of the outlet opening. In embodiments the
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method includes moving the profiling member such that the profiling member
translates along at least one axis and/or rotates about at least one axis to
adjust the
size and/or shape of the outlet opening.
[00319] Embodiments of a slurry distributor, a cementitious slurry mixing
and
dispensing assembly, and methods of using the same are provided herein which
can
provide many enhanced process features helpful in manufacturing cementitious
products, such as gypsum wallboard in a commercial setting. A slurry
distributor
constructed in accordance with principles of the present disclosure can
facilitate the
spreading of aqueous calcined gypsum slurry upon a moving web of cover sheet
material as it advances past a mixer at the wet end of the manufacturing line
toward
a forming station.
[00320] A gypsum slurry mixing and dispensing assembly constructed in
accordance with principles of the present disclosure can split a flow of
aqueous
calcined gypsum slurry from a mixer into two separate flows of aqueous
calcined
gypsum slurry which can be recombined downstream in a slurry distributor
constructed in accordance with principles of the present disclosure to provide
a
desired spreading pattern. The design of the dual inlet configuration and the
distribution outlet can allow for wider spreading of more viscous slurry in
the cross-
machine direction over the moving web of cover sheet material. The slurry
distributor can be adapted such that the two separate flows of aqueous
calcined
gypsum slurry enter a slurry distributor along feed inlet directions which
include a
cross-machine direction component, are re-directed inside the slurry
distributor such
that the two flows of slurry are moving in substantially a machine direction,
and are
recombined in the distributor in a way to enhance the cross-direction
uniformity of
the combined flows of aqueous calcined gypsum slurry being discharged from the
distribution outlet of the slurry distributor to help reduce mass flow
variation over time
along the transverse axis or cross machine direction. Introducing the first
and
second flows of aqueous calcined gypsum slurry in first and second feed
directions
that include a cross-machine directional component can help the re-combined
flows
of slurry discharge from the slurry distributor with a reduced momentum and/or
energy.
[00321] The interior flow cavity of the slurry distributor can be configured
such that
each of the two flows of slurry move through the slurry distributor in a
streamline
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flow. The interior flow cavity of the slurry distributor can be configured
such that
each of the two flows of slurry move through the slurry distributor with
minimal or
substantially no air-liquid slurry phase separation. The interior flow cavity
of the
slurry distributor can be configured such that each of the two flows of slurry
move
through the slurry distributor substantially without undergoing a vortex flow
path.
[00322] A gypsum slurry mixing and dispensing assembly constructed in
accordance with principles of the present disclosure can include flow geometry
upstream of the distribution outlet of the slurry distributor to reduce the
slurry velocity
in one or multiple steps. For example, a flow splitter can be provided between
the
mixer and the slurry distributor to reduce the slurry velocity entering the
slurry
distributor. As another example, the flow geometry in the gypsum slurry mixing
and
dispensing assembly can include areas of expansion upstream and within the
slurry
distributor to slow down the slurry so it is manageable when it is discharged
from the
distribution outlet of the slurry distributor.
[00323] The geometry of the distribution outlet can also help control the
discharge
velocity and momentum of the slurry as it is being discharged from the slurry
distributor upon the moving web of cover sheet material. The flow geometry of
the
slurry distributor can be adapted such that the slurry discharging from the
distribution
outlet is maintained in substantially a two-dimensional flow pattern with a
relatively
small height in comparison to the wider outlet in the cross-machine direction
to help
improve stability and uniformity.
[00324] The relatively wide discharge outlet yields a momentum per unit width
of
the slurry being discharged from the distribution outlet that is lower than
the
momentum per unit width of a slurry discharged from a conventional boot under
similar operating conditions. The reduced momentum per unit width can help
prevent washout of a skim coat of a dense layer applied to the web of cover
sheet
material upstream from the location where the slurry is discharged from the
slurry
distributor upon the web.
[00325] In the situation where a conventional boot outlet is 6 inches wide and
2
inches thick is used, the average velocity of the outlet for a high volume
product can
be about 761 ft/min. In embodiments where the slurry distributor constructed
in
accordance with principles of the present disclosure includes a distribution
outlet
having an opening that is 24 inches wide and 0.75 inches thick, the average
velocity
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can be about 550 ft/min. The mass flow rate is the same for both devices at
3,437
lb/min. The momentum of the slurry (mass flow rate*average velocity) for both
cases
would be ¨2,618,000 and 1,891,000 lb=ft/min2 for the conventional boot and the
slurry distributor, respectively. Dividing the respective calculated momentum
by the
widths of the conventional boot outlet and the slurry distributor outlet, the
momentum
per unit width of the slurry discharging from the convention boot is 402,736
(lb=ft/min2)/(inch across boot width), and the momentum per unit width of the
slurry
discharging from the slurry distributor constructed in accordance with
principles of
the present disclosure is 78,776 (lb=ft/min2)/(inch across slurry distributor
width). In
this case, the slurry discharging from the slurry distributor has about 20% of
the
momentum per unit width compared to the conventional boot.
[00326] A slurry distributor constructed in accordance with principles of the
present
disclosure can achieve a desired spreading pattern while using an aqueous
calcined
gypsum slurry over a broad range of water-stucco ratios, including a
relatively low
WSR or a more conventional WSR, such as, a water-to-calcined gypsum ratio from
about 0.4 to about 1.2, for example, below 0.75 in some embodiments, and
between
about 0.4 and about 0.8 in other embodiments. Embodiments of a slurry
distributor
constructed in accordance with principles of the present disclosure can
include
internal flow geometry adapted to generate controlled shear effects upon the
first
and second flows of aqueous calcined gypsum slurry as the first and second
flows
advance from the first and second feed inlets through the slurry distributor
toward the
distribution outlet. The application of controlled shear in the slurry
distributor can
selectively reduce the viscosity of the slurry as a result of being subjected
to such
shear. Under the effects of controlled shear in the slurry distributor, slurry
having a
lower water-stucco ratio can be distributed from the slurry distributor with a
spread
pattern in the cross-machine direction comparable to slurries having a
conventional
WSR.
[00327] The interior flow geometry of the slurry distributor can be adapted to
further accommodate slurries of various water-stucco ratios to provide
increase flow
adjacent the boundary wall regions of the interior geometry of the slurry
distributor.
By including flow geometry features in the slurry distributor adapted to
increase the
degree of flow around the boundary wall layers, the tendency of slurry to re-
circulate
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in the slurry distributor and/or stop flowing and set therein is reduced.
Accordingly,
the build up of set slurry in the slurry distributor can be reduced as a
result.
[00328] A slurry distributor constructed in accordance with principles of the
present
disclosure can include a profile system mounted adjacent the distribution
outlet to
alter a cross machine velocity component of the combined flows of slurry
discharging
from the distribution outlet to selectively control the spread angle and
spread width of
the slurry in the cross machine direction on the substrate moving down the
manufacturing line toward the forming station. The profile system can help the
slurry
discharged from the distribution outlet achieve a desired spread pattern while
being
less sensitive to slurry viscosity and WSR. The profile system can be used to
change the flow dynamics of the slurry discharging from the distribution
outlet of the
slurry distributor to guide slurry flow such that the slurry has more uniform
velocity in
the cross-machine direction. Using the profile system can also help a gypsum
slurry
mixing and dispensing assembly constructed in accordance with principles of
the
present disclosure be used in a gypsum wallboard manufacturing setting to
produce
wallboard of different types and volumes.
[00329] Thus, in an embodiment, a slurry distributor comprises a distribution
conduit extending generally along a longitudinal axis and includes an entry
portion, a
distribution outlet in fluid communication with the entry portion, and a
bottom surface
extending between the entry portion and the distribution outlet. The
distribution outlet
extends a predetermined distance along a transverse axis with the transverse
axis
being substantially perpendicular to the longitudinal axis. A slurry wiping
mechanism
including a movable wiper blade is in contacting relationship with the bottom
surface
of the distribution conduit. The wiper blade is reciprocally movable over a
clearing
path between a first position and a second position. The clearing path is
disposed
adjacent to the distribution outlet.
[00330] In another embodiment, the distribution outlet includes an outlet
opening
having a width, along the transverse axis, and a height, along a vertical axis
mutually
perpendicular to the longitudinal axis and the transverse axis, wherein the
width-to-
height ratio of the outlet opening is about 4 or more.
[00331] In another embodiment, the distribution outlet includes an outlet
opening
having a width, along the transverse axis, and a wiper blade extending a
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predetermined second distance along the transverse axis. The width of the
outlet
opening is smaller than the second distance along the transverse axis such
that the
wiper blade is wider than the outlet opening.
[003321 In another embodiment, the wiper blade reciprocally moves
longitudinally
along the clearing path, and the first position of the wiper blade is
longitudinally
upstream of the distribution outlet, while the second position is
longitudinally
downstream of the distribution outlet.
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[00333] In another embodiment, the slurry wiping mechanism includes an
actuator
operably arranged with the wiper blade to selectively reciprocally move the
wiper
blade.
[00334] In another embodiment, the actuator comprises a pneumatic cylinder
having a reciprocally movable piston. The piston is connected to the wiper
blade.
[00335] In another embodiment, the slurry wiping mechanism includes a
controller.
The controller is adapted to selectively control the actuator to reciprocally
move the
wiper blade.
[00336] In another embodiment, the controller is adapted to move the wiper
blade
in a clearing direction from the first position to the second position over a
wiping
stroke, and the controller is adapted to move the wiper blade in an opposing,
return
direction from the second position to the first position over a return stroke.
The
controller is adapted to move the wiper blade such that the time to move over
the
wiping stroke is substantially the same as the time to move over the return
stroke.
[00337] In another embodiment, the controller is adapted to move the wiper
blade
in a clearing direction from the first position to the second position over a
wiping
stroke, and the controller is adapted to move the wiper blade in an opposing,
return
direction from the second position to the first position over a return stroke.
The
controller is adapted to move the wiper blade reciprocally between the first
position
and the second position in a cycle having a sweep period. The sweep period
includes a wiping portion comprising the time to move over the wiping stroke,
a
returning portion comprising the time to move over the return stroke, and an
accumulation delay portion comprising a predetermined period of time in which
the
wiper blade remains in the first position.
[00338] In another embodiment, the wiping portion is substantially the same as
the
returning portion.
[00339] In another embodiment, the accumulation delay portion is adjustable.
[00340] In another embodiment, the slurry distributor further comprises a
feed
conduit including a first entry segment with a first feed inlet and a second
entry
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segment with a second feed inlet disposed in spaced relationship to the first
feed
inlet. The entry portion is in fluid communication with the first and second
feed inlets
of the feed conduit.
[00341] In another embodiment, the first and second feed inlets and the first
and
second entry segments are disposed at a respective feed angle in a range up to
about 135 with respect to the longitudinal axis.
[00342] In another embodiment, a cementitious slurry mixing and dispensing
assembly comprises a mixer adapted to agitate water and a cementitious
material to
form an aqueous cementitious slurry and a slurry distributor in fluid
communication
with the mixer. The slurry distributor includes a distribution conduit
extending
generally along a longitudinal axis and includes an entry portion. A
distribution outlet
is in fluid communication with the entry portion. A bottom surface extends
between
the entry portion and the distribution outlet. The distribution outlet extends
a
predetermined distance along a transverse axis, with the transverse axis being
substantially perpendicular to the longitudinal axis. The slurry distributor
also
includes a slurry wiping mechanism including a movable wiper blade in
contacting
relationship with the bottom surface of the distribution conduit. The wiper
blade
reciprocally movable over a clearing path between a first position and a
second
position, with the clearing path disposed adjacent the distribution outlet.
[00343] In another embodiment, the cementitious slurry mixing and dispensing
assembly has a distribution outlet including an outlet opening having a width,
along
the transverse axis. The wiper blade extends a predetermined second distance
along the transverse axis, and reciprocally moves longitudinally along the
clearing
path.
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[00344] In another embodiment, the cementitious slurry mixing and dispensing
assembly further comprises a bottom support member supporting the bottom
surface
of the distribution conduit. The bottom support member has a perimeter. The
distribution outlet is longitudinally offset from the bottom support member
such that a
distal outlet portion of the distribution conduit extends from the perimeter
of the
bottom support member. The wiper blade supports the distal outlet portion of
the
slurry distributor when the wiper blade is in the first position.
[00345] In another embodiment, the cementitious slurry mixing and dispensing
assembly further comprises a delivery conduit disposed between and in fluid
communication with the mixer and the slurry distributor, a flow-modifying
element
associated with the delivery conduit and adapted to control a flow of the
aqueous
cementitious slurry from the mixer, and an aqueous foam supply conduit in
fluid
communication with at least one of the mixer and the delivery conduit.
[00346] In another embodiment, the cementitious slurry mixing and dispensing
assembly has a slurry distributor including a feed conduit including a first
entry
segment with a first feed inlet and a second entry segment with a second feed
inlet
disposed in spaced relationship to the first feed inlet. The entry portion of
the
distribution conduit is in fluid communication with the first and second feed
inlets of
the feed conduit. The first feed inlet is adapted to receive a first flow of
aqueous
cementitious slurry from the mixer. The second feed inlet is adapted to
receive a
second flow of aqueous cementitious slurry from the mixer. The distribution
outlet is
in fluid communication with both the first and the second feed inlets and
adapted
such that the first and second flows of aqueous cementitious slurry discharge
from
the slurry distributor through the distribution outlet.
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[00347] In another embodiment, the gympsum slurry mixing and dispensing
assembly further comprises a delivery conduit disposed between and in fluid
communication with the mixer and the slurry distributor. The delivery conduit
includes a main delivery trunk and first and second delivery branches. A flow
splitter
joins the main delivery trunk and the first and second delivery branches. The
flow
splitter is disposed between the main delivery trunk and the first delivery
branch and
between the main delivery trunk and the second delivery branch. The first
delivery
branch is in fluid communication with the first feed inlet of the slurry
distributor, and
the second delivery branch is in fluid communication with the second feed
inlet of the
slurry distributor.
[00348] In another embodiment, a method of preparing a cementitious product
comprises: (a) discharging a flow of aqueous cementitious slurry from a mixer;
(b)
passing the flow of aqueous cementitious slurry through an entry portion of a
distribution conduit of a slurry distributor; (c) discharging the flow of
aqueous
cementitious slurry from a distribution outlet of the slurry distributor upon
a web of
cover sheet material moving along a machine direction; and (d) reciprocally
moving a
wiper blade over a clearing path along a bottom surface of the distribution
conduit
between a first position and a second position to clear aqueous cementitious
slurry
therefrom, the clearing path disposed adjacent the distribution outlet.
[00349] In another embodiment, a method of preparing a cementitious product
includes the distribution conduit extending generally along a longitudinal
axis
between the entry portion and the distribution outlet. The wiper blade
reciprocally
moves longitudinally along the clearing path.
[00350] In another embodiment, a method of preparing a cementitious product
includes the wiper blade moving in a clearing direction from the first
position to the
second position over a wiping stroke, and the wiper blade moving in an
opposing,
return direction from the second position to the first position over a return
stroke. The
wiper blade reciprocally moves such that the time to move over the wiping
stroke is
substantially the same as the time to move over the return stroke.
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[00351] In another embodiment, a method of preparing a cementitious product
includes the wiper blade moving in a clearing direction from the first
position to the
second position over a wiping stroke, and the wiper blade moving in an
opposing,
return direction from the second position to the first position over a return
stroke. The
wiper blade reciprocally moves between the first position and the second
position in
a cycle having a sweep period. The sweep period including a wiping portion
comprising the time to move over the wiping stroke, a returning portion
comprising
the time to move over the return stroke, and an accumulation delay portion
comprising a predetermined period of time in which the wiper blade remains in
the
first position.
[00352] In another embodiment, a method of preparing a cementitious product
includes the wiping portion being substantially the same as the returning
portion.
[00353] In another embodiment, a method of preparing a cementitious product
includes the accumulation delay portion being adjustable.
EXAMPLES
[00354] Referring to FIG. 65, the geometry and flow characteristics of an
embodiment of a slurry distributor constructed in accordance with principles
of the
present disclosure were evaluated in Examples 1-3. A top plan view of a half
portion
1205 of a slurry distributor is shown in FIG. 65. The half portion 1205 of the
slurry
distributor includes a half portion 1207 of a feed conduit 320 and a half
portion 1209
of a distribution conduit 328. The half portion 1207 of the feed conduit 322
includes
a second feed inlet 325 defining a second opening 335, a second entry segment
337, and a half portion 1211 of a bifurcated connector segment 339. The half
portion
1209 of the distribution conduit 328 includes a half portion 1214 of an entry
portion
352 of the distribution conduit 328 and a half portion 1217 of a distribution
outlet 330.
[00355] It should be understood that another half portion of a slurry
distributor,
which is a mirror image of the half portion 1205 of FIG. 65, can be integrally
joined
and aligned with the half portion 1205 of FIG. 65 at a transverse central
midpoint 387
of the distribution outlet 330 to form a slurry distributor which is
substantially similar
to the slurry distributor 420 of FIG. 15. Accordingly, the geometry and flow
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characteristics described below are equally applicable to the mirror image
half
portion of the slurry distributor as well.
[00356] Referring to FIG. 72, the geometry and flow characteristics of another
embodiment of a slurry distributor 2020 constructed in accordance with
principles of
the present disclosure were evaluated in Examples 4-6. The slurry distributor
2020
shown in FIG. 72 is substantially the same as the slurry distributor 1420 of
FIG. 34.
The flow characteristics of the slurry distributor 2020 of FIG. 72 using a
profiling
mechanism constructed in accordance with principles of the present disclosure
were
evaluated in Example 7. The profiling mechanism evaluated in Example 7 is
substantially the same as the profiling mechanism 1432 of FIG. 22.
EXAMPLE 1
[00357] In this Example and referring to FIG. 65, the particular geometry
of the half
portion 1205 of the slurry distributor was evaluated at sixteen different
locations L1-16
between a first location L1 at the second feed inlet 325 and a sixteenth
location L16 at
a half portion 1207 of the distribution outlet 330. Each location L1-16
represents a
cross-sectional slice of the half portion 1205 of the slurry distributor as
indicated by
the corresponding line. A flow line 1212 along the geometric center of each
cross-
sectional slice was used to determine the distance between adjacent locations
416.
The eleventh location L11 corresponds to the half portion 1214 of the entry
portion
352 of the distribution conduit 328 which corresponds to an opening 342 of a
second
feed outlet 345 of the half portion 1207 of the feed conduit 320. Accordingly,
the first
through the tenth locations L1_10 are taken in the half portion 1207 of the
feed conduit
320, and the eleventh through the sixteenth locations are taken in the half
portion
1209 of the distribution conduit 328.
[00358] For each location L1-16, the following geometric values were
determined:
the distance along the flow line 1212 between the second feed inlet 325 and
the
particular location L1-16; the cross-sectional area of the opening at the
location L116;
the perimeter of the location L1_16; and the hydraulic diameter of the
location L1-16.
The hydraulic diameter was calculated using the following formula:
Dhyd = 4 x A / P (Eq. 1)
where Dhyd is the hydraulic diameter,
A is the area of the particular location L1..16, and
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P is the perimeter of the particular location L1-16.
Using the inlet conditions, the dimensionless values for each location L1-16
can be
determined to describe the interior flow geometry, as shown in Table 1. Curve-
fit
equations were used to describe the dimensionless geometry of the half portion
1205 of the slurry distributor in FIG. 66, which shows the dimensionless
distance
from inlet versus the dimensionless area and the hydraulic diameter.
[00359] The analysis of the dimensionless values for each location L1-16 shows
that
the cross sectional flow area increases from the first location L1 at the
second feed
inlet 325 to the eleventh location L11 at the half portion 1214 of the entry
portion 352
(also the opening 342 of the second feed outlet 345). In the exemplary
embodiment,
the cross-sectional flow area at the half portion 1214 of the entry portion
352 is about
1/3 larger than the cross-sectional flow area at the second feed inlet 325.
Between
the first location L1 and the eleventh location L11, the cross-sectional flow
area of the
second entry segment 337 and the second shaped duct 339 varies from location
to
location L1_11. In this region, at least two adjacent locations L6, L7 are
configured
such that the location L7 located further from the second feed inlet 325 has a
cross
sectional flow area that is smaller than the adjacent location L6 that is
closer to the
second feed inlet 325.
[00360] Between the first location L1 and the eleventh location L11, in the
half
portion 1207 of the feed conduit 322 there is an area of expansion (e.g., 46)
having
a cross-sectional flow area that is greater than a cross-sectional flow area
of an
adjacent area (e.g., L3) upstream from the area of expansion in a direction
from the
second inlet 335 toward the half portion 1217 of the distribution outlet 330.
The
second entry segment 337 and the second shaped duct 341 have a cross section
that varies along the direction of flow 1212 to help distribute the second
flow of slurry
moving therethrough.
[00361] The cross sectional area decreases from the eleventh location L11 at
the
half portion 1214 of the entry portion 352 of the distribution conduit 328 to
the
sixteenth location L16 at the half portion 1217 of the distribution outlet 330
of the
distribution conduit 328. In the exemplary embodiment, the cross-sectional
flow area
of the half portion 1214 of an entry portion 352 is about 95% of that of the
half
portion 1217 of the distribution outlet 330.
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[00362] The cross-sectional flow area at the first location L1 at the second
feed
inlet 325 is smaller than the cross-sectional flow area at the sixteenth
location L16 at
the half portion 1217 of the distribution outlet 330 of the distribution
conduit 328. In
the exemplary embodiment, the cross-sectional flow area at the half portion
1217 of
the distribution outlet 330 of the distribution conduit 328 is about 1/4
larger than the
cross-sectional flow area at the second feed inlet 325.
[00363] The hydraulic diameter decreases from the first location L1 at the
second
feed inlet 325 to the eleventh location L11 at the half portion 1214 of the
entry portion
352 of the distribution conduit 328. In the exemplary embodiment, the
hydraulic
diameter at the half portion 1214 of the entry portion 352 of the distribution
conduit
328 is about 1/2 the hydraulic diameter at the second feed inlet 325.
[00364] The hydraulic diameter decreases from the eleventh location L11 at the
half
portion 1214 of an entry portion 352 of the distribution conduit 328 to the
sixteenth
location L16 at the half portion 1217 of the distribution outlet 330 of the
distribution
conduit 328. In the exemplary embodiment, the hydraulic diameter of the half
portion
1217 of the distribution outlet 330 of the distribution conduit 328 is about
95% of that
of the half portion 1214 of the entry portion 352 of the distribution conduit
328.
[00365] The hydraulic diameter at the first location L1 at the second inlet
325 is
larger than the hydraulic diameter at the sixteenth location L16 at the half
portion
1217 of the distribution outlet 330 of the distribution conduit 328. In the
exemplary
embodiment, the hydraulic diameter at the half portion 1217 of the
distribution outlet
330 of the distribution conduit 328 is less than about half of that of the
second feed
inlet 325.
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TABLE I - GEOMETRY
Dimensionless
Location Distance Area Perimeter Hydraulic
From Dia.
Inlet
L1 0.00 1.00 1.00 1.00
L2 0.07 1.00 1.00 1.00
L3 0.14 0.91 0.98 0.93
L4 0.20 1.01 1.07 0.94
L5 0.27 1.18 1.24 0.95
L6 0.34 1.25 1.45 0.87
L7 0.41 1.16 1.68 0.69
L8 0.47 1.13 1.93 0.59
L9 0.54 1.23 2.20 0.56
L10 0.61 1.35 2.47 0.55
L11 0.68 1.33 2.73 0.49
L12 0.75 1.28 2.70 0.47
L13 0.81 1.27 2.68 0.48
L14 0.88 1.26 2.67 0.47
L15 0.95 1.26 2.67 0.47
L16 1.00 1.26 2.67 0.47
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EXAMPLE 2
[00366] In this Example, the half portion 1205 of the slurry distributor of
FIG. 65 was
used to model the flow of gypsum slurry therethrough under different flow
conditions.
For all flow conditions, the density (p) of the aqueous gypsum slurry was set
at 1,000
kg/m3. Aqueous gypsum slurry is a shear-thinning material such that as shear
is
applied to it, its viscosity can decrease. The viscosity (p) Pa.s of the
gypsum slurry was
calculated using the Power Law Fluid Model which has the following equation:
p = K2> n-1 (Eq. 2)
where,
K is a constant,
is the shear rate, and
n is a constant equal to 0.133 in this case.
[00367] In a first flow condition, the gypsum slurry has a viscosity K
factor of 50 in the
Power Law model and enters the second feed inlet 325 at 2.5 m/s. A
computational
fluid dynamics technique with a finite volume method was used to determine
flow
characteristics in the distributor. At each location L1-16, the following flow
characteristics
were determined: area-weighted average velocity (U), area-weighted average
shear
rate (j/), viscosity calculated using the Power Law Model (Eq. 2), shear
stress, and
Reynolds Number (Re).
[00368] The shear stress was calculated using the following equation:
Shear stress =px (Eq. 3)
where
p is the viscosity calculated using the Power Law Model (Eq. 2), and
2> is the shear rate.
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[00369] The Reynolds Number was calculated using the following equation:
Re==pxUxDhyd/p (Eq. 4)
where
p is the density of the gypsum slurry,
U is the area-weighted average velocity,
Dhyd is the hydraulic diameter, and
p is the viscosity calculated using the Power Law Model (Eq. 2).
[00370] In a second flow condition case, the feed velocity of the gypsum
slurry into
the second feed inlet 325 was increased to 3.55 m/s. All other conditions were
the
same as in the first flow condition of this Example. The dimensional values
for the
mentioned flow characteristics at each location L1-16 for both the first flow
condition
where the inlet velocity is 2.5 m/s and the second flow condition where the
inlet velocity
is 3.55 m/s were modeled. Using the inlet conditions, dimensionless values of
the flow
characteristics for each location L1_16 were determined, as shown in Table II.
[00371] For both flow conditions where K was set equal to 50, the average
velocity
was reduced from the first location L1 at the second feed inlet 325 to the
sixteenth
location L16 at the half portion 1217 of the distribution outlet 330 of the
distribution
conduit 328. In the illustrated embodiment, the average velocity was reduced
by about
1/5, as shown in FIG. 67.
[00372] For both flow conditions, the shear rate increased from the first
location L1 at
the second feed inlet 325 to the sixteenth location L16 at the half portion
1217 of the
distribution outlet 330 of the distribution conduit 328. In the illustrated
embodiment, the
shear rate approximately doubled from the first location L1 at the second feed
inlet 325
to the sixteenth location L16 at the half portion 1217 of the distribution
outlet 330 of the
distribution conduit 328, as shown in FIG. 68.
[00373] For both flow conditions, the calculated viscosity was reduced from
the first
location L1 at the second feed inlet 325 to the sixteenth location L16 at the
half portion
1217 of the distribution outlet 330 of the distribution conduit 328. In the
illustrated
embodiment, the calculated viscosity was reduced from the first location L1 at
the
second feed inlet 325 to the sixteenth location L16 at the half portion 1217
of the
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distribution outlet 330 of the distribution conduit 328 by about half, as
illustrated in FIG.
69.
[00374] For both flow conditions in FIG. 70, the shear stress increased
from the first
location Li at the second feed inlet 325 to the sixteenth location L16 at the
half portion
1217 of the distribution outlet 330 of the distribution conduit 328. In the
illustrated
embodiment, the shear stress increased by about 10% from the first location Li
at the
second feed inlet 325 to the sixteenth location L16 at the half portion 1217
of the
distribution outlet 330 of the distribution conduit 328.
[00375] For both flow conditions, the Reynolds number in FIG. 71 was reduced
from
the first location Li at the second feed inlet 325 to the sixteenth location
L16 at the half
portion 1217 of the distribution outlet 330 of the distribution conduit 328.
In the
illustrated embodiment, the Reynolds number was reduced from the first
location L1 at
the second feed inlet 325 to the sixteenth location L16 at the half portion
1217 of the
distribution outlet 330 of the distribution conduit 328 by about 1/3. For both
flow
conditions, the Reynolds number at the sixteenth location L16 at the half
portion 1217 of
the distribution outlet 330 of the distribution conduit 328 is in the laminar
region.
TABLE II- DIMENSIONLESS FLOW CHARACTERISTICS (K = 50)
o
w
=
.6.
Inlet Velocity = 2.50 m/s Inlet Velocity = 3.55 m/s 'a
c,
c,
Location
w
Shear Calc ShearShear Calc Shear
oe
Velocity Re Velocity
Re ,...,
Rate Visc. Stress Rate Visc.
Stress
L1 1.00 1.00 1.00 1.00 1.00 1.00 1.00
1.00 1.00 1.00
L2 1.00 1.18 0.87 1.02 1.15 1.00 1.20
0.85 1.03 1.17
L3 1.10 1.36 0.77 1.04 1.33 1.10 1.40
0.75 1.05 1.36
L4 1.00 1.30 0.80 1.04 1.18 0.99 1.32
0.79 1.04 1.19
P
L5 0.86 1.19 0.86 1.02 0.96 0.86 1.22
0.84 1.03 0.98 2
00
00
00
00
L6 0.83 1.23 0.83 1.03 0.86 0.83 1.28
0.81 1.03 0.89
00
L7 0.90 1.65 0.65 1.07 0.96 0.90 1.73
0.62 1.08 0.99
,
L8 0.90 1.73 0.62 1.08 0.85 0.90 1.80
0.60 1.08 0.88 .
,
L9 0.82 1.67 0.64 1.07 0.72 0.82 1.74
0.62 1.08 0.74
L10 0.77 1.63 0.65 1.07 0.64 0.77 1.73
0.62 1.08 0.68
L11 0.76 1.83 0.59 1.08 0.62 0.76 1.93
0.57 1.09 0.65
L12 0.78 1.84 0.59 1.08 0.63 0.78 1.92
0.57 1.09 0.65
,-o
L13 0.78 1.88 0.58 1.09 0.64 0.78 1.93
0.57 1.09 0.65 n
,-i
L14 0.78 1.88 0.58 1.09 0.64 0.78 1.95
0.56 1.09 0.66
cp
w
=
L15 0.78 1.85 0.59 1.09 0.63 0.78 1.92
0.57 1.09 0.65 ..
,...,
'a
0,
L16 0.79 1.89 0.58 1.09 0.65 0.79 1.98
0.55 1.09 0.67 0,
=
=
00
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EXAMPLE 3
[00376] In this Example, the half portion 1205 of the slurry distributor of
FIG. 65 was
used to model the flow of gypsum slurry therethrough under flow conditions
similar to
those in Example 2 except that the value for the coefficient K in the Power
Law Model
(Eq. 2) was set at 100. The flow conditions were similar to those in Example 2
in other
respects.
[00377] Again, the flow characteristics were evaluated both for a feed
velocity of the
gypsum slurry into the second feed inlet 325 of 2.50 m/s and of 3.55 m/s. At
each
location L1-16, the following flow characteristics were determined: area-
weighted average
velocity (U), area-weighted average shear rate (jf), viscosity calculated
using the Power
Law Model (Eq. 2), shear stress (Eq. 3), and Reynolds Number (Re) (Eq. 4).
Using the
inlet conditions, dimensionless values of the flow characteristics for each
location L1-16
were determined, as shown in Table III.
[00378] For both flow conditions where K was set equal to 100, the average
velocity
was reduced from the first location Li at the second feed inlet 325 to the
sixteenth
location L16 at the half portion 1217 of the distribution outlet 330 of the
distribution
conduit 328. In the illustrated embodiment, the average velocity was reduced
by about
1/5. The results for average velocity, on a dimensionless basis, were
substantially the
same as those in Example 2 and FIG. 67.
[00379] For both flow conditions, the shear rate increased from the first
location Li at
the second feed inlet 325 to the sixteenth location L16 at the half portion
1217 of the
distribution outlet 330 of the distribution conduit 328. In the illustrated
embodiment, the
shear rate approximately doubled from the first location Li at the second feed
inlet 325
to the sixteenth location L16 at the half portion 1217 of the distribution
outlet 330 of the
distribution conduit 328. The results for shear rate, on a dimensionless
basis, were
substantially the same as those in Example 2 and FIG. 68.
[00380] For both flow conditions, the calculated viscosity was reduced from
the first
location Li at the second feed inlet 325 to the sixteenth location L16 at the
half portion
1217 of the distribution outlet 330 of the distribution conduit 328. in the
illustrated
embodiment, the calculated viscosity was reduced from the first location Li at
the
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second feed inlet 325 to the sixteenth location Li6 at the half portion 1217
of the
distribution outlet 330 of the distribution conduit 328 by about half. The
results for the
calculated viscosity, on a dimensionless basis, were substantially the same as
those in
Example 2 and FIG. 69.
[00381] For both flow conditions, the shear stress increased from the first
location Li
at the second feed inlet 325 to the sixteenth location L16 at the half portion
1217 of the
distribution outlet 330 of the distribution conduit 328. In the illustrated
embodiment, the
shear stress increased by about 10% from the first location Li at the second
feed inlet
325 to the sixteenth location L16 at the half portion 1217 of the distribution
outlet 330 of
the distribution conduit 328. The results for the shear stress, on a
dimensionless basis,
were substantially the same as those in Example 2 and FIG. 70.
[00382] For both flow conditions, the Reynolds number was reduced from the
first
location Li at the second feed inlet 325 to the sixteenth location L16 at the
half portion
1217 of the distribution outlet 330 of the distribution conduit 328. In the
illustrated
embodiment, the Reynolds number was reduced from the first location Li at the
second
feed inlet 325 to the sixteenth location L16 at the half portion 1217 of the
distribution
outlet 330 of the distribution conduit 328 by about 1/3. For both flow
conditions, the
Reynolds number at the sixteenth location L16 at the half portion 1217 of the
distribution
outlet 330 of the distribution conduit 328 is in the laminar region. The
results for the
Reynolds number, on a dimensionless basis, were substantially the same as
those in
Example 2 and FIG. 71.
[00383] FIGS. 67-71 are graphs of the flow characteristics computed for the
different
flow conditions of Examples 2 and 3. Curve-fit equations were used to describe
the
change in the flow characteristics over the distance between the feed inlet to
the half
portion of the distribution outlet. Accordingly, Examples 2 and 3 show that
the flow
characteristics are consistent over variations in inlet velocity and/or
viscosity.
TABLE III - DIMENSIONLESS FLOW CHARACTERISTICS (K = 100)
o
w
=
.6.
Inlet Velocity = 2.50 m/s Inlet Velocity = 3.55 m/s 'a
c,
Location
c,
w
Shear Calc Shear Shear Calc
Shear oe
Velocity Re Velocity
Re ,...,
Rate Visc. Stress Rate Visc.
Stress
L1 1.00 1.00 1.00 1.00 1.00 1.00 1.00
1.00 1.00 1.00
L2 1.00 1.16 0.88 1.02 1.13 1.00 1.21
0.85 1.03 1.18
,
L3 1.10 1.35 0.77 1.04 1.32 1.10 1.39
0.75 1.04 1.35
L4 1.00 1.28 0.80 1.03 1.17 1.00 1.35
0.77 1.04 1.22
P
L5 0.87 1.15 0.88 1.02 0.94 0.86 1.23
0.84 1.03 0.99 2
03
03
03
L6 0.83 1.18 0.87 1.02 0.83 0.83 1.27
0.81 1.03 0.88 3
L7 0.90 1.60 0.66 1.06 0.93 0.90 1.70
0.63 1.07 0.98
,
L8 0.90 1.70 0.63 1.07 0.84 0.90 1.77
0.61 1.08 0.87 .
,
L9 0.82 1.61 0.66 1.07 0.69 0.82 1.71
0.63 1.07 0.73
L10 0.77 1.57 0.68 1.06 0.62 0.77 1.67
0.64 1.07 0.66
L11 0.76 1.76 0.61 1.08 0.60 0.76 1.88
0.58 1.09 0.64
L12 0.78 1.79 0.60 1.08 0.61 0.78 1.90
0.57 1.09 0.64
,-o
L13 0.78 1.81 0.60 1.08 0.62 0.78 1.93
0.57 1.09 0.65 n
,-i
L14 0.78 1.84 0.59 1.08 0.63 0.78 1.94
0.56 1.09 0.66
cp
w
=
L15 0.78 1.80 0.60 1.08 0.62 0.78 1.90
0.57 1.09 0.64 ..
,...,
'a
L16 0.79 1.87 0.58 1.09 0.64 0.79 1.96
0.56 1.09 0.67 0,
0,
=
=
00
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EXAMPLE 4
[00384] In this Example, the slurry distributor 2020 of FIG. 72 was used to
model the
flow of gypsum slurry at one of the bulb portions 2120 of the feed conduit
2022.
Referring to FIG. 72, the first and second entry segments 2036, 2037 of the
slurry
distributor 2020 each have a diameter D. The slurry distributor 2020 has a
length, along
the longitudinal axis, of about 12xD. The slurry distributor 2020 is
symmetrical about a
central longitudinal axis 50 extending generally in the machine direction
2192. The
slurry distributor 2020 can be separated into two half portions 2004, 2005
which are
substantially symmetrical about the central longitudinal axis.
[00385] Referring to FIG. 73, the half portion 2004 of the slurry
distributor of FIG. 72
was used to model the flow of gypsum slurry therethrough under flow conditions
similar
to those in Example 2 except using different dimensionless expressions of
velocity. An
inlet diameter D (x* = x/D) was selected as the length scale to non-
dimensionalize the
position vector x (x* = x/D), and an average inlet velocity (U) was used as
the velocity
scale to non-dimensionalize velocity vector u (u* = u/U). The flow conditions
were
similar to those in Example 2 in other respects.
[00386] Referring to FIGS. 73-76, a computational fluid dynamics (CFD)
technique
with a finite volume method was used to determine flow characteristics in the
half
portion of the distributor. In particular, average velocities at different
vertical locations
from the area A were calculated. The area extending about 0.75D from a center
of the
entry segment at area A was analyzed. Twelve radially-spaced vertical slices
were
analyzed to calculate twelve different average slurry velocities radially
around the bulb
portion. The twelve locations were substantially radially spaced apart such
that each
adjacent radial location is about 30 apart. Referring to FIGS. 75 and 76,
radial location
1 corresponds to a direction in opposing relationship to the machine direction
2192, and
radial location 7 corresponds to the machine direction 2192. Radial locations
4 and 10
are substantially aligned with the transverse axis 60.
[00387] The CFD technique was used with two different inlet velocity
conditions,
u1 = U and u2 = 1.5U. The results of the CFD analysis are found in Table IV.
Magnitude of velocity is expressed as a dimensionless absolute value (lur =
jul/U). The
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data is also plotted in FIG. 77. It should be understood that the other half
portion 2005
of the slurry distributor 2020 would exhibit similar flow characteristics.
[00388] For both flow conditions, the average velocity at each radial location
1-12 was
less than the inlet velocity, but was greater than zero. The average velocity
ranged
from about half to about 7/8 of the inlet velocity (u* ¨ 0.48 to 0.83 of the
inlet velocity).
The contoured convex dimple surface in the bulb portion helped redirect flow
from the
entry segment radially outward in all directions.
[00389] The slurry velocity also slowed down relative to the inlet velocity.
The
average velocity of all twelve radial locations for a given flow condition was
substantially
similar (¨ 0.65 or 65% of inlet velocity).
[00390] Also, in each flow condition, the highest average velocities occurred
at radial
locations 3-5 and 9-11. The higher average velocity along the transverse axis,
or along
the cross-machine direction 60, help provide more edge flow to the lateral
sidewalls.
[00391] Accordingly, this Example illustrates the bulb portion 2120 helps slow
down
the slurry and change the direction of the slurry from a downward vertical
direction to a
radially outward horizontal plane. Furthermore, the bulb portion 2120 helps
divert slurry
flow to the lateral outer and inner sidewalls of the shaped duct of the half
portion 2004
of the slurry distributor 2020 to encourage slurry movement in the cross-
machine
direction 60.
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TABLE IV ¨ DIMENSIONLESS RADIAL
VELOCITY DISTRIBUTION
Inlet Velocity U = U
1 U2 = 1.5 U
Location u* = u/Ui u* = U/U2
R1 0.48 0.50
R2 0.56 0.60
R3 0.68 0.74
R4 0.76 0.72
R5 0.75 0.72
R6 0.60 0.49
R7 0.59 0.57
R8 0.58 0.58
R9 0.79 0.82
R10 0.79 0.83
R11 0.72 0.75
R12 0.53 0.61
Average u* 0.65 0.66
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EXAMPLE 5
[00392] In this Example, the slurry distributor 2020 of FIG. 72 was used to
model the
flow of gypsum slurry at one of the shaped ducts 2041 of the feed conduit
2022.
Referring to FIG. 78, the half portion 2004 of the slurry distributor 2020 of
FIG. 72 was
used to model the flow of gypsum slurry therethrough under flow conditions
similar to
those in Example 2 except using a dimensionless expression of velocity similar
to that in
Example 4. In particular, the swirl motion of the slurry at the lateral inner
and outer
walls of the shaped duct was analyzed.
[00393] Referring to FIGS. 73, 74, and 78, a computational fluid dynamics
(CFD)
technique with a finite volume method was used to determine flow
characteristics in the
half portion 2004 of the distributor 2020. In particular, the swirl motion of
the slurry near
the lateral inner and outer sidewalls of the shaped duct 2041 was analyzed.
Referring
to FIG 73, the slurry moves in a swirling manner as it enters the shaped duct
2041. As
the slurry moves along the machine direction 2192 to the distribution outlet
2030, the
slurry streamlines become more ordered. The swirl motion of the slurry was
analyzed in
a region of the shaped duct 2041 at a longitudinal location of about 1-3/4 D
(1.72D) in
areas B1 and B2, as shown in FIGS. 74 and 78.
[00394] The swirl motion of the slurry is a function of its tangential
velocity and its
axial (or machine direction) velocity. Referring to FIG. 78, the degree of
swirl for
swirling flow is usually characterized by the swirl number (S) as the fluxes
of angular
and linear momentum using the following formula:
= Momentum of Tangential Velocity Component
S _____
Momentum of Axial Velocity Component
(
fwurdr
Eq. 5)
with w = tangential velocity and u = axial velocity
fuurdr
and r represents the radial location.
[00395] If the average values of tangential velocity and axial velocity are
used in
Equation 5, it becomes:
Average Tangential Velocity Wave
S
(Eq. 6)
Average Axial Velocity U ave
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For this Example, the characteristic swirl motion (Sm) is expressed using the
following
formula:
Maximum Tangential Velocity
(Eq. 7)
Average Axial Velocity
In this Example, the calculated swirl motion was used to calculate the swirl
angle using
the following formula:
Swirl Angle¨ tan"' (Sm) (Eq. 8).
[00396] The CFD technique was used with two different dimensionless inlet
velocity
conditions, u1 = U and u2 = 1.5U. The results of the CFD analysis are found in
Table V.
It should be understood that the other half portion of the slurry distributor
would exhibit
similar flow characteristics. Through this analysis it has been found that in
embodiments, the slurry distributor can be constructed to produce a swirl
motion Sm in a
range from about zero to about 10 in the slurry distributor and a swirl angle
in a range
from about zero degrees to about 84 .
[00397] For both flow conditions, the maximum tangential velocity at the edges
was at
least about half of the inlet velocity in an edge region of the entry portion
of the shaped
duct. The swirl motion near the lateral sidewalls is expected to help maintain
the
cleanliness of the interior geometry of the slurry distributor while in use.
As shown in
FIG. 73, the swirl motion of the slurry decreases along the machine axis 50 in
the
direction of flow to the distribution outlet 2030.
TABLE V ¨ SWIRL MOTION
Ui = U U2 = 1.5 U
Inlet Velocity
u* = u/Ui u* = u/U2
MD Location = 1.72 D B1 B2 B1 B2
Max Tangential
0.50 0.75 0.55 0.74
Velocity
Ave Axial Velocity 0.71 0.63 0.67 0.65
Lower Bound Upper Bound
Swirl Motion, Sm 0.71 1.19 0.82 1.14 0 10
Swirl Angle ( ) 35 50 39 49 0 84
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EXAMPLE 6
[00398] In this Example, the slurry distributor 2020 of FIG. 72 was used to
model the
flow of gypsum slurry through the feed conduit 2022 and the distribution
conduit 2028.
Referring to FIGS. 73 and 74, the half portion 2004 of the slurry distributor
2020 of FIG.
72 was used to model the flow of gypsum slurry therethrough under flow
conditions
similar to those in Example 2 except using a dimensionless expression of
velocity
similar to that in Example 4.
[00399] For all flow conditions, the density (p) of the aqueous gypsum slurry
was set
at 1,000 kg/m3 and the viscosity K factor was set at 50. Again, the flow
characteristics
were evaluated both for a dimensionless feed velocity of the gypsum slurry
into the feed
inlet 2024 of B and of 1.5B. The following flow characteristics were
determined at each
successive dimensionless location downstream from the entry portion of the
shaped
duct 2041 along the machine direction 2192 expressed as a function of the
inlet
diameter D: area-weighted average velocity (U), area-weighted average shear
rate (22),
viscosity calculated using the Power Law Model (Eq. 2), and Reynolds Number
(Re)
(Eq. 4). The hydraulic diameter (Eq. 1) was also calculated at the noted
successive
dimensionless locations along the longitudinal axis 50. Using the inlet flow
conditions,
dimensionless values of the flow characteristics for each location were
determined, as
shown in Table VI.
[00400] FIGS. 79-82 are graphs of the flow characteristics computed for the
different
flow conditions of Example 6. Curve-fit equations were used to describe the
change in
the flow characteristics over the distance between the feed inlet to the half
portion 2004
of the distribution outlet 2030. Accordingly, the Examples show that the flow
characteristics are consistent over variations in inlet velocity.
[00401] For both flow conditions, the average velocity was reduced from the
first
location (about 3D) in the feed conduit to the last location (about 12D) at
the half portion
2117 of the distribution outlet 2030 of the distribution conduit 2028. The
average
velocity substantially progressively decreased as the slurry moved along the
machine
direction 2192. In the illustrated embodiment, the average velocity was
reduced by
about 1/3 from the inlet velocity, as shown in FIG. 79.
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[00402] For both flow conditions, the shear rate increased from the first
location
(about 3D) in the feed conduit 2022 to the last location (about 12D) at the
half portion
2117 of the distribution outlet 2030 of the distribution conduit 2028. The
shear rate
varied from location to location. In the illustrated embodiment, the shear
rate increased
at the half portion 2117 of the distribution outlet 2030 of the distribution
conduit 2028
relative to the inlet, as shown in FIG. 80.
[00403] For both flow conditions, the calculated viscosity was reduced from
the first
location (about 3D) in the feed conduit to the last location (about 12D) at
the half portion
2117 of the distribution outlet 2030 of the distribution conduit 2028. The
calculated
viscosity varied from location to location. In the illustrated embodiment, the
calculated
viscosity decreased at the half portion 2117 of the distribution outlet 2030
of the
distribution conduit 2028 relative to the inlet, as shown in FIG. 81.
[00404] For both flow conditions, the Reynolds number in FIG. 82 was reduced
from
the first location (about 3D) in the feed conduit to the last location (about
12D) at the
half portion 2117 of the ditribution outlet 2030 of the distribution conduit
2028. In the
illustrated embodiment, the Reynolds number decreased at half portion 2117 of
the
distribution outlet 2030 of the distribution conduit 2028 relative to the
inlet by about 1/2.
For both flow conditions, the Reynolds number at the half portion 2117 of the
distribution outlet 2030 of the distribution conduit 2028 is in the laminar
region.
[00405] Accordingly, it has been found that the distal half of the slurry
distributor
(between about 6D and about 12D) is configured to provide a flow stabilization
region in
which the average velocity of the slurry and the Reynolds number are generally
stable
and decreased relative to the feed inlet conditions. As shown in FIG. 73, the
slurry
moves in generally a streamline fashion along the machine direction 2192
through this
flow stabilization region.
TABLE VI- DIMENSIONLESS FLOW CHARACTERISTICS (K = 50)
0
w
=
Geometry Inlet Velocity = U1
Inlet Velocity = U2 .6.
o=
o=
w
oe
MD Hydraulic Shear Calc
Shear Calc ,...,
Velocity Re
Velocity Re
Distance Dia. Rate Visc.
Rate Visc.
3.11 0.35 0.74 1.08 0.93 0.55
0.75 1.09 0.93 0.56
4.31 0.31 0.74 1.19 0.86 0.53
0.75 1.21 0.85 0.54
. 5.51 0.31 0.71 1.17 0.87 0.50
0.72 1.18 0.86 0.50 P
(ll
.
Iv
00
00
6.71 0.31 0.68 1.11 0.91 0.46
0.69 1.12 0.91 0.46 03
-
0,
,õ
7.91 0.32 0.66 1.05 0.95 0.44
0.66 1.06 0.95 0.44
,
8.92 0.31 0.66 1.07 0.94 0.43
0.66 1.07 0.94 0.43
9.93 0.31 0.66 1.09 0.93 0.43
0.66 1.09 0.93 0.43
10.94 0.30 0.66 1.11 0.91 0.43
0.66 1.11 0.91 0.43
11.95 0.30 0.66 1.13 0.89 0.43
0.66 1.14 0.89 0.43
n
,-i
cp
w
=
,...,
'a
c,
c,
=
=
oe
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EXAMPLE 7
[00406] In this Example, the slurry distributor 2020 of FIG. 72 was used to
model the
flow of gypsum slurry at the distribution outlet 2030 of the distribution
conduit 2028. In
this Example, the half portion 2004 of the slurry distributor of FIG. 73 was
used to model
the flow of gypsum slurry therethrough under flow conditions similar to those
in Example
2 except using a dimensionless expression of the width of the outlet opening
2081. A
dimensionless width (w/VV) across the half portion 2119 of the outlet opening
2081 of
the distribution outlet 2030 (with a centerline at the transverse central
midpoint 2187
being equal to zero as shown in FIG. 72). The flow conditions were similar to
those in
Example 2 in other respects.
[00407] A CFD technique with a finite volume method was used to determine flow
characteristics in the half portion 2004 of the distributor 2020. In
particular, the angle of
spread of the slurry discharging from the outlet opening 2081 at various
locations
across the width of the half portion 2119 of the outlet opening 2081 of the
distribution
outlet 2030 was analyzed. The angle of spread was determined using the
following
formula:
angle of spread = taril(VxNz),
(Eq. 9)
where Vx is the average velocity in the cross-machine direction and
Vz is the average velocity in the machine direction.
[00408] The angle of spread was calculated for two different conditions: one
in which
the profiling mechanism did not compress the outlet opening 2081 ("no
profiler") and
one in which the profiling mechanism compressed the outlet opening 2081
("profiler").
In the modeled slurry distributor 2020, the outlet opening 2081 has a height
of about 3/4
of an inch across its entire width of approximately ten inches for each half
portion 2004,
2005, for a total of twenty inches for the total width of the outlet opening
2081. The
modeled profiling mechanism has a profile member that is about 15 inches wide
and is
aligned with the transverse central midpoint such that a lateral portion of
the distribution
outlet is in offset relationship with the profiling member and is
uncompressed. In the
modeled "profiler" condition, the profiling mechanism compresses the outlet
opening by
about 1/8 of an inch such that the outlet opening is about 5/8 of an inch in
the area
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underneath the profiling member. The angle of spread for both conditions was
determined, as shown in Table VII.
1004091 Under both conditions, the angle of spread increases as the location
moves
further outward from the transverse central midpoint 2187 (width = 0). The
angle of
spread is greatest at the lateral edge of the outlet opening 2081.
1004101 The angle of spread increased by using the profiling mechanism to
compress
the discharge outlet 2030, thereby reducing the height of the outlet opening
2081. In
the modeled "profiler" condition, the maximum angle of spread at the lateral
edge (width
= 0.466) increased over 25 percent relative to the "no profiler" condition. In
the "profiler"
condition, the average angle of spread increased by over 50 percent relative
to the "no
profiler" condition.
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TABLE VII- SLURRY SPREAD ANGLE WITH
PROFILING MECHANISM
Outlet Width Location Spread Angle( )
(relative to centerline)
No Profiler Profiler
0.017 0.108 0.093
0.052 0.232 0.435
0.086 0.440 0.739
0.121 0.561 1.032
0.155 0.634 1.374
0.190 0.981 1.800
0.224 1.279 2.402
0.259 1.458 3.079
0.293 1.848 3.612
0.328 2.173 3.941
0.362 2.298 4.027
0.397 2.488 3.972
0.431 2.857 4.020
0.466 3.208 4.064
AVERAGE 1.469 2.471
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[00411] All references, including publications, patent applications, and
patents,
cited herein are hereby incorporated by reference to the same extent as if
each
reference were individually and specifically indicated to be incorporated by
reference
and were set forth in its entirety herein.
[00412] The use of the terms "a" and "an" and "the" and similar referents in
the
context of describing the invention (especially in the context of the
following claims)
are to be construed to cover both the singular and the plural, unless
otherwise
indicated herein or clearly contradicted by context. The terms "comprising,"
"having,"
"including," and "containing" are to be construed as open-ended terms (i.e.,
meaning
"including, but not limited to,") unless otherwise noted. Recitation of ranges
of
values herein are merely intended to serve as a shorthand method of referring
individually to each separate value falling within the range, unless otherwise
indicated herein, and each separate value is incorporated into the
specification as if
it were individually recited herein. All methods described herein can be
performed in
any suitable order unless otherwise indicated herein or otherwise clearly
contradicted by context. The use of any and all examples, or exemplary
language
(e.g., "such as") provided herein, is intended merely to better illuminate the
invention
and does not pose a limitation on the scope of the invention unless otherwise
claimed. No language in the specification should be construed as indicating
any
non-claimed element as essential to the practice of the invention.
[00413] Preferred embodiments of this invention are described herein,
including
the best mode known to the inventors for carrying out the invention.
Variations of
those preferred embodiments may become apparent to those of ordinary skill in
the
art upon reading the foregoing description. The inventors expect skilled
artisans to
employ such variations as appropriate, and the inventors intend for the
invention to
be practiced otherwise than as specifically described herein. Accordingly,
this
invention includes all modifications and equivalents of the subject matter
recited in
the claims appended hereto as permitted by applicable law. Moreover, any
combination of the above-described elements in all possible variations thereof
is
encompassed by the invention unless otherwise indicated herein or otherwise
clearly
contradicted by context.
