Note: Descriptions are shown in the official language in which they were submitted.
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Docket 57635-CA
TANGENTIAL SEPARATOR
FIELD OF THE INVENTION
The present invention relates to air separators
5 and more particularly to an improved method and apparatus
for separating and accumulating airborne material.
BACRGROUND OF THE INVENTION
A wide variety of separators have been
developed that separate and accumulate various objects
transported by an air stream, such as paper waste, scrap
material, food items, or other products. These
separators utilize various configurations which are
designed to receive a high velocity stream of air
transporting prescribed objects, and subsequently
15 separate the objects from the conveying air. The objects
are typically accumulated at or near a designated exit,
while the air or other transport gas is directed to a
second exit. A problFm associated with many separating
systems, and particularly in separating systems design
20 for the collection of scrap paper, is that they typically
generate a large amount of dust and/or other air-borne
contaminants proximate the material exit.
One type of separator that has been extensively
used is a cyclone separator wherein the transported
25 objects and a stream of air are introduced into a large
cylindrical or cone-shaped device. The transported
objects are introduced into the cylindrical housing so
that they are thrust against the outer wall by
centrifugal forces resulting from the flow of the air
30 stream within the cylinder. The air exits via the top of
the cylindrical device while the objects are typically
funneled out a bottom exit. Cyclone separators are
generally very large and somewhat expensive pieces of
mechanical equipment. Cyclone type separators are often
35 so large that it is not feasible to install them inside a
building. Consequently, most cyclone type separators are
CA 02216178 1997-09-17
typically situated outside the building and often on the
roof of the building. Reducing the dust in these
exterior cyclone separators has not been of great concern
because the presence of dust outside a building typically
does not adversely affect people or equipment.
A prior art cyclone separator system that is
concerned with the separation of dust from the
transported objects is disclosed in United States Patent
No. 3,116,238 issued to Van Etten. The '238 patent
discloses a modified cyclone-type separator that includes
a standard central air discharge member which conducts
air from the cyclone-type separator. It also includes a
screen disposed along one outer wall of the separator to
facilitate the separation and removal of dust and fine
particles from the stream of air and conveyed material.
While this device attempts to address the problem caused
by dust being associated with the stream being conveyed,
there remain several other problems associated with this
patented device. Namely, it still requires a very large
device, and the air within the housing remains at a high
velocity and thus a relatively high static pressure.
Another type of separator is a tangential
separator where the transported objects are recovered on
a flat or cylindrical screen and the air which passes
through the screen exits the separator in a generally
tangential orientation. Tangential separators are
typically smaller devices than the cyclone separators and
thus are often installed within the confines of a
building or factory. For this reason, the air exiting
the tangential separator is typically reintroduced into
the interior environment of the building or is reused
within the air conveying system. In either situation, it
becomes increasingly important to filter the exiting air
prior to its reuse and to minimize the dust and other
contaminants introduced into the environment near the
material exit.
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Most applications in which tangential air
separators are used can be classified either as a
positive ("push type") system, a draw through ("pull
type") system, or a hybrid system. As the classification
5 suggests, draw through or "pull type" systems are those
in which the air stream and transported objects are
pulled into the separator with a fan located downstream
of the separator. In such draw through systems, the
separator is typically maintained below atmospheric
10 pressure and typically requires an air lock to prevent
any back flow of air from the object discharge exit.
Positive or "push type" systems, on the other hand,
include systems where the air and conveyed objects are
blown into the separator with the fan located upstream of
15 the separator. In push type systems, the pressure within
the separator is above standard atmospheric pressure.
The hybrid systems involve both "pushing" as well as
"pulling" of the conveying air stream such that an ideal
pressure is maintained within the separator.
20 Clearly, the static pressure within the
tangential separator is an important design
consideration. Consider for the moment, a push type
paper conveying and separation system where the paper
material exits the separator and falls to a baler or
25 compactor. If the static pressure at the material exit
of the separator unit is too high, dust and paper scraps
tend to swirl around the material exit resulting in a
somewhat untidy and very dusty environment proximate the
material exit. However, if the static pressure at the
30 air and material inlet in the separator unit is too low,
the result is an inefficient conveying system susceptible
to clogging.
Pull type systems and hybrid type systems
alleviate some of the aforementioned static pressure
35 concerns but are generally more complex and more
expensive systems. Moreover, the push type tangential
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separator systems are often the simplest to design, and
are easy to install and maintain.
One related art tangential air separator is
disclosed in United States Patent No. 4,900,345 issued to
Le Jeune which discloses the use of a deformed
cylindrical grid in a tangential separator which allows
most of the air flow to exit tangentially through the
separator. The remainder of the air together~with the
transported objects presumably exit through a central
10 exit portion of the separator via the spiral nature of
the deformed cylindrical grid.
Another related art tangential separator system
is disclosed in United States Patent No. 4,300,926 issued
to Brooks which discloses a separation apparatus adapted
15 to receive a stream of airborne material and which
includes a single rear exit screen and a bottom material
exit. An adjustable baffle is located near the separator
inlet directing the incoming stream to the rear exit
screen which allows the air to exit tangentially while
20 the material continues to be transported through
separator. The separator is designed with an increasing
cross-sectional area for decelerating the transported
material as it moves through the duct.
Still another related art system is disclosed
25 in United States Patent No. 4,484,843 issued to McGlinsky
et al. which shows a multi-chamber pneumatic conveying
scrap paper system that also utilizes a flat rear exit
screen for passing air and dust while the paper is
directed and/or falls downward to a gathering hopper.
30 While these related art systems may adequately
separate the transported material from the air stream,
there remains a need to provide an improved tangential
separator that is relatively small device, yet simple to
install, operate and maintain and, more importantly, that
35 facilitates the relatively clean discharge of material.
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BUMMARY OF THE INVENTION
In one aspect, a tangential air separator for
separating material transported by air has now been
constructed which includes a casing having a tangential
5 inlet adapted to receive a stream of air and material and
a plurality of air exits. The separator casing includes
a perforated arcuate outer wall proximate the inlet which
is disposed in the direct path of the incoming air stream
and which functions as a means for peripherally removing
10 a portion of the air from the stream of air and material
received at the inlet. An important advantage offered by
this perforated wall is that it decreases the velocity of
the stream of air transporting the material and also
reduces the static pressure within the separator casing.
15 A second air separation device is disposed in the
interior of the casing and is designed to further
separate the air from the material entrained therein,
leaving mostly the transported material.
Two separate and distinct air exits are
20 provided. A first air exhaust conduit is peripherally
attached to the casing and operatively associated with
the arcuate boundary wall, and a second air exhaust
conduit is operatively associated with the interior air
separation device. A third exit from the separator
25 casing serves as the material discharge exit which, like
the inlet, is located along the circumference of the
generally cylindrical casing. Because of the multiple
air exits, the static pressure is relatively low at the
material discharge exit, thus avoiding significant
30 problems normally associated with swirling dust and
particles near the collection site.
Another aspect of the invention is realized
through the coupling of two separators in a loop
configuration in a manner that significantly reduces the
35 static pressure proximate the material discharge and thus
the dust at the collection site. Two such separators are
coupled such that the entire material discharge from the
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first separator is conveyed via a stream of air to the
input of the second separator, and the air exhaust of the
second separator is recycled as one of a plurality of air
input streams entering the first separator.
5 Still another aspect of the invention is
realized by partitioning the air exhaust conduit into a
plurality of parallel passageways which can be
individually closed off. Each passageway includes an air
nozzle or the like through which a compressed air blast
10 can be introduced into the passageway which reverses the
air flow and cleans a section of the perforated outer
wall of accumulated material. By sequentially closing
each passageway one-by-one during the cleaning operation,
there is no need to Brut down the separating operation
15 for cleaning. Rather, while one section of the
perforated outer wall aligned with one passageway is
being cleaned, the other passageways continue to permit
the exhaust flow of air from the cylindrical casing as
part of the separation process. In this manner, all the
20 sections of the perforated outer wall can be sequentially
cleared of accumulating material without ceasing the
material separating operation.
The invention may also be characterized as a
method for separating material transported by air which
25 comprises the steps of: receiving one or more streams of
air and material at a tangential inlet into a casing:
removing a portion of air from the stream of air and
material via a peripheral air exit located proximate to
the inlet in order to decrease the velocity of the air
30 transporting the material and to reduce the static
pressure within the casing: directing the removed portion
of air away from the casing via a first exhaust conduit;
separating further air from the material within the
interior of the casing and transporting such separated
35 air out of the casing via a second exhaust conduit; and
discharging the material remaining in the casing via a
material outlet located at the periphery of the casing at
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a location spaced from the inlet. Advantageously, the
first air exhaust conduit is partitioned into a plurality
of passageways so that accumulating material and dust can
be sequentially cleaned from sections of the peripheral
5 air exit without halting the above-described method.
Optionally, the material-separating method
further comprises the steps of: conveying the discharged
material from the first separator via an air stream to an
inlet of a second separator: separating a portion of the
10 air which enters the second separator via a peripheral
air exit and further centrally separating air from
the material within the second separator so as to
reduce the static pressure at a lower material discharge
exit therefrom: directing the removed portion of air back
15 to the first separator by applying suction from a relay
blower: and discharging the material from the second
separator through such lower exit into an underlying
baler.
The present method and apparatus for separating
20 airborne material realizes the aforementioned features
and advantages in a manner that is clearly evident from a
thorough consideration of the detailed description when
taken in conjunction with the drawings wherein there is
shown and described illustrative embodiments of the
25 invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following detailed description,
reference will be made to the attached drawings in which:
FIG. 1 is a perspective view of a tangential
30 separator system for separating, accumulating and baling
airborne material, such as paper scrap, which employs a
separator embodying various features of the present
invention;
FIG. 2 is a side elevational view of the
35 central separator illustrated in FIG. 1 with the air
inlet conduit shown spaced from its point of connection;
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FIG. 3 is a front view of the separator
illustrated in FIG. 1;
FIG. 4 is a side cross-sectional view of the
separator similar to FIG. 2, but looking from the
opposite end generally along line 4-4 of FIG. 3:
FIG. 5 is a cross-sectional view taken along
line 5-5 of FIG. 2 illustrating the perforated outer wall
of the separator:
FIG. 6 is a front elevational view of the
interior perforated hollow cylinder shown in section in
FIG. 4;
FIG. 7 is a side view of an alternative
embodiment of a separator embodying various features of
the invention;
FIG. 8 is a front view of the separator
illustrated in FIG. 7;
FIG. 9 is a top view of the separator apparatus
illustrated in FIG. 7;
FIG. 10 is a top view of another embodiment of
a tangential separating system for separating and
accumulating airborne material, embodying various
features of the present invention;
FIG. 11 is a fragmentary side view of the
separating system illustrated in FIG. 10 with some
components omitted to better show the primary separator;
FIG. 12 is a fragmentary side view of a portion
of the system illustrated in FIG. 10 showing the
secondary separator positioned atop the baler, taken from
a location between it and the primary separator;
FIG. 13 is a fragmentary top view, enlarged in
size, and partly in section of a portion of the system
shown in FIG. 10 which operates as a screen cleaning
mechanism for the separator; and
FIG. 14 is an enlarged fragmentary side view of
looking at the right-hand side.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there is illustrated a
tangential air separator system 10 particularly suited
for separating material, such as scrap paper or scrap
corrugated fiberboard, which is conveyed in a stream of
air inside a factory or other building. The illustrated
tangential air separating system l0 includes an inlet
duct 12 or network of inlet ducts, a tangential separator
apparatus 14, an outlet chute 16 leading from a material
discharge exit 18 of the separator apparatus 14 to a
baler or compactor 20, and a plurality of air exhaust
conduits 22, 24 extending away from the separator
apparatus 14. The illustrated system 10 is a "push type"
tangential separator wherein the air stream carrying the
conveyed material is blown through the inlet duct 12 into
the separator apparatus 14 using a blower or fan (not
shown) associated with the inlet duct 12 and located
upstream of the separator apparatus 14. The conveyed
material is effectively separated from the air stream
within a separating chamber 30 within the apparatus 14.
Most of the air stream exits the separating chamber 30
via the air exhaust conduits 22, 24 while the conveyed
material exits via the material discharge exit 18 to the
chute 16 heading to a baler or compactor 20. The air
being discharged through the air exhaust conduits 22, 24
is then filtered and subsequently recycled and/or re-
introduced into the immediate environment or discharged
to the atmosphere exterior of the building.
The size of the separator apparatus 14 and
associated ducting is very much dependent on the volume
of the air stream necessary to efficiently convey the
material as well as the general character of the scrap
paper being separated. Further, the illustrated
embodiment can be easily modified to include multiple
inlets and/or multiple separating chambers sharing the
same air exhaust conduits.
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FIGS. 2 and 3 illustrate side and front views
of the separator apparatus 14. As seen therein, the
separator apparatus 14 is a generally cylindrical shaped
casing 32 having a tangentially oriented air and material
5 inlet 34 located at or near the top 36 of the cylindrical
casing 32. For example, a typical inlet 34 may be a 10
inch by 29 inch rectangular opening 38 with a two inch
wide flange or collar 40 disposed around its perimeter to
facilitate attachment to the inlet duct 12. The
10 illustrated embodiment further includes an inlet
transition adapter 42 having a length of about 39.5
inches to facilitate connection between a standard 18
inch diameter inlet duct 12 and the rectangular opening
38 of the air and material inlet 34 on the separator
15 apparatus 14. Advantageously, the inlet transition
adapter also increases the cross sectional area of the
incoming duct, e.g. by about 15%, thereby slowing the
velocity of the airstream slightly.
The separator apparatus 14 further has a
20 material discharge exit 18 is located at the bottom 44 of
the generally cylindrical casing 32. For example, the
material discharge exit 18 may be a 29 inch by 29 inch
opening 46 with a two inch wide flange 48 disposed around
the perimeter of the opening 46 to facilitate connection
25 to the feed chute 16 leading to the baler 20.
The illustrated separator apparatus includes
the two air exhaust conduits 22, 24 and has a separator
chamber access door 50. The first air exhaust conduit 22
is peripherally attached immediately downstream of a
30 perforated back outer or boundary wall 52 which forms a
section of the circular cross section cylindrical casing
32 and leads away therefrom to an air outlet 54 located
from the cylindrical casing 32. The second air exhaust
conduit 24 is connected to a side or end wall 56 of the
35 cylindrical casing 32 and is in fluid communication with
the interior of the cylindrical casing 32 which provides
the separating chamber 30. In particular, the
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illustrated separator apparatus 14 has a 36 inch diameter
hole 58 centrally located in one end wall 56 of the
generally cylindrical casing 32, with a standard 36 inch
diameter angle ring 60 extending from the side hole 58
5 for engagement with the second air exhaust conduit 24.
The separated air that is being exhausted through the
conduits 22 and 24 has a substantially free flow path to
the atmosphere within or outside the plant although it
may be routed through a bag filter or the like.
10 FIG. 4 is a cross-section view of the separator
apparatus 14 depicting the separating chamber 30 and its
operative elements which separate air from the stream of
air and material in two distinct stages. The first stage
of air separation is accomplished by the strategically
15 located perforated arcuate back outer wall 52 of the
cylindrical casing 32 leading to the first air exhaust
conduit 22. The second stage of air separation is
accomplished by a perforated hollow cylinder 64 of
circular cross section centrally disposed in the
20 separating chamber 30, i.e. generally coaxial with the
cylindrical casing 32. The interior of the perforated
metal hollow cylinder 64 communicates with the second air
exhaust conduit 24 through the side hole 58 as seen in
FIG. 1, and it is conveniently dimensioned with about the
25 same diameter as the hole.
As seen more clearly in FIG. 5, the perforated
arcuate wall 52 extends downward from the top 36 of the
cylindrical casing 32 and constitutes a substantial
portion of the its back wall. The cross sectional area
30 of the surface of the perforated wall 52 may be about
18.4 square feet. The perforated wall is preferably #12
gauge perforated sheet steel with a plurality of 0.15625
inch diameter holes 66 separated by 0.1865 inch and
having staggered centers. Similarly, as seen in FIG. 6,
35 the perforated hollow cylinder or tube 64 is
advantageously made of the same #12 gauge sheet steel
perforated with a plurality of 0.15625 inch diameter
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holes 68 and might be dimensioned to form a 36-inch
diameter tube about 29 inches long. The perforated
hollow cylinder 64 is stationary and coaxially mounted
within the cylindrical casing 32 in alignment with the
5 side hole 58. The angle ring 60 which is affixed to the
end wall 56 may be used to support one end of the hollow
cylinder 64 and to serve as a connector for engagement
with the second air exhaust conduit 24. Relative to the
18.4 sq. Feet back wall, the perforated cylinder 64 may
10 have a cross sectional area of about 22.5 square feet.
In operation, the incoming stream of air and
material enters the separating chamber 30 via the inlet
transition adapter 42 (See FIGS. 1 and 4). In addition
to connecting the separator apparatus 14 to the standard
15 inlet ducting 12, the inlet transition adapter 42 also
acts to slightly decelerate the stream due to the
generally increased cross-sectional area of the inlet
transition adapter 42. As the mixed stream enters the
separating chamber 30, it encounters the perforated
20 surface 52 of the separator apparatus 14. The dimensions
of the perforations 66 and cross sectional area of the
arcuate perforated surface 52 are chosen such that
between about 50% and 75%, and more preferably about 60~
of the volume of the air stream is immediately removed
25 (i.e. passes through the back wall perforations) by
separation from the transported material which slides
along the arcuate surface and remains within the
separating chamber 30 at this location. Much of the
material slides along the outer or back wall 52 of the
30 cylindrical casing 32 in a downward direction as a result
of the forces created by this tangential entry into the
generally right circular cylindrical configuration of the
separating chamber 30. This natural segregation of the
formerly entrained material in the region adjacent the
35 outer wall facilitates the separation of much of the
residual air from the material through the centrally
disposed perforated hollow cylinder 64. Again, the
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perforation size and dimensions of the perforated hollow
cylinder 64 are chosen to allow most of the remaining
air, and only the air, to escape. The formerly entrained
material moving in such a generally arcuate path around
5 the cylindrical casing reaches the bottom 44 of the
casing 32 where it exits via the material discharge exit
18. Typically the material falls through a feed chute 16
into the hopper of a horizontal compactor or baler 20.
The strategically centrally disposed perforated hollow
10 cylinder further slows the velocity of the material and
the remaining air entering the opening 46 and
substantially reduces the static pressure of this
location within the casing.
Overall, the pressure drop between the inlet
15 duct 12 and the material discharge exit 18 is preferably
accomplished in three discrete steps. First, a small
pressure drop is realized as the incoming air flow
traverses the inlet transition adapter 42. Preferably,
an expansion of about 15% is effected at this location;
20 for example, the cross-sectional area of inlet transition
adapter 42 may gradually decrease from approximately 254
in2 at the entrance to about 290 in2 where it discharges
to the inlet 34 to the separating chamber 30. Second, a
major pressure drop is realized due to the removal of a
25 substantial volume of the air via the perforated arcuate
boundary wall 52. A final major pressure drop results
from the separation of further air from the material
centrally within the interior of the separating chamber
and the subsequent removal of that air through the side
30 exhaust conduit 24. The shape, location, and the
dimensions of both perforated walls 52 and 64 relative to
one another are important as well as their positions and
orientations ~o the inlet 34 and material discharge exit
18. It is the result of these design considerations that
35 the present separator apparatus 14 achieves a pressure
drop of a magnitude which has heretofore not been
accomplished in a "push-type" separator system.
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The combination of separating air at two stages
within a single separator apparatus, one peripherally
positioned along a boundary and one centrally located
within the generally cylindrical casing, provide a
synergistic effect resulting in a greater than expected
reduction in static pressure across the separator casing.
By way of comparison, the present embodiment demonstrates
about a 25% lower level of static pressure near the
material discharge exit than a comparably sized "push-
type" separator having only a centrally disposed exit.
Likewise, the present embodiment is believed to have a
much lower static pressure near the material discharge
exit than a comparably sized "push-type" separator having
only a peripheral exit located at a boundary of the
casing. This dual air separation feature minimizes the
problems associated with swirling dust and other
particles near the ultimate collection site, i.e. the
baler hopper, and allows the design of the separator to
be made even more compact than previous designs for
accommodating a comparable volume of flow, while
achieving comparable effectiveness.
The air exiting the separating chamber 30 is
channeled by the multiple exhaust conduits 22, 24 and
usually released at locations that are distant from the
separator apparatus 14. Air flows freely through the air
exhaust conduits 22, 24 and can be discharged within the
building for re-use to convey additional material or can
be discharged exterior of the building. An appropriate
bag filter or the like can be incorporated within such
air exhaust conduits 22, 24, and such is preferred when
the air is discharged inside the building.
Considering the operation of the presently
described embodiment, the preferred method of separating
material transported by a stream of air is defined by
four essential steps. These four steps include: (1)
receiving a stream of air and material through an inlet
to a casing which is oriented tangentially at the arcuate
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periphery of a generally cylindrical casing, which casing
is of larger cross section than the inlet so expansion
will occur; (2) removing a major portion of the air from
the incoming stream by separating it via a perforated
5 arcuate outer or boundary of the casing that is located
closely downstream of the inlet: (3) separating most of
the remaining air from the material within the interior
of the casing using a secondary separating device; and
(4) discharging the formerly entrained material through a
10 material outlet located at the bottom of the casing which
is spaced around the circular periphery from the inlet a
distance equal to at least about 180° of arc, as a result
of which an unexpectedly large pressure drop is realized
between the inlet and the material discharge exit. As
15 indicated above, the pressure drop between the inlet and
the material discharge exit is accomplished in three
discrete stages corresponding to steps (1) through (3)
above, with the air being separated in steps (2) and (3)
above being channeled away from the casing to one or more
20 air outlets by separate exhaust conduits through which
the air can flow freely.
An alternative embodiment of a tangential
separator 84 of this general type is illustrated in FIGS.
7-9. The separator 84 includes an inlet 86 for a stream
25 of air and material, a generally cylindrical separating
chamber 88, a bottom material discharge exit 90 and a
plurality of air exhaust conduits 92, 94a and 94b
extending from the chamber that lead to a common air
outlet 96. The conveying air is effectively separated
30 from the material within the separating chamber 88 which
comprises a cylindrical casing 102 of generally right
circular cylindrical configuration having a perforated
metal back wail 98 and within which a perforated hollow
cylinder 104 is centrally disposed.
35 The separator illustrated in FIGS. 7-9 closely
resembles that described with reference to FIGS. 1-6 with
the exception of including three air exhaust conduits 92,
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94a and 94b. The separator 84 again incorporates two
distinct separating stages. The perforated arcuate back
outer wall 98 of the generally cylindrical casing 102
separates a major portion of the air from the material
5 being conveyed. In particular, as the stream of air and
entrained material tangentially enters the separating
chamber 88 via the inlet 86, it impacts upon the
perforated arcuate wall 98 of the casing 102 through
which a major portion of the air passes while the
10 entrained material slides along the surface and is
directed in a downward direction along the arcuate
perforated surface. The dimensions of the perforations
and cross sectional area of the perforated wall 98 are
chosen such that between about 50% and 75%, and more
15 preferably about 60% of the volume of the entering air
stream passes through the perforations.
The remaining portion of the air in the
entering stream finds a ready exit in a perforated hollow
cylinder 104 which is centrally disposed in the
20 separating chamber 88, positioned generally coaxial to
the cylindrical casing 102. The size of the perforations
as well as the dimensions of the perforated hollow
cylinder 104 are chosen to allow much of the remaining
air from the entering stream to be separated from the
25 material. The air passing through the perforated
cylinder 104 exits the casing 102 via dual air exhaust
conduits 94a and 94b which respectively communicate with
each end 106, 108 of the perforated cylinder 104 and
which are affixed to the respective end walls 110, 112 of
30 the casing. The formerly entrained material continues
along the arcuate path to the bottom of the casing 102
where it exits via material discharge exit 90.
The: central air exhaust conduits 94a and 94b
advantageously provide bi-directional flow of the air out
35 of the separating chamber 88 through each side thereof,
and such bi-directional flow from the center of the
separator 84 further promotes air removal and tends to
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maintain the air exit velocity at moderate levels. The
plurality of air exhaust conduits 92, 94a and 94b are
joined together at a location downstream from the
separator 84 into a common air outlet 96. If desired,
5 the air exiting the separator can be passed through a
filter (not shown) to remove dust before the exit air is
discharged either inside or outside of the building.
Such an arrangement retains the advantage of having
multiple air exits from the separator while simplifying
10 the incorporation of a filter, preferably one which
allows relatively free flow of air from the casing to the
eventual outlet.
A further improved tangential separating system
130 is shown in FIGS. 10-12 which is particularly well-
15 suited for handling paper and corrugated board scrap from
a corrugated box-making plant. In the separating system
130, a pair of separators 132 and 134 are coupled in a
loop configuration in a manner that still further reduces
the static pressure at the material collection site below
20 an outlet 136 from the separator 134. The two separators
are coupled such that the material exiting an outlet 138
at the bottom of the first separator 132 is conveyed in a
stream of air driven by a main relay blower 139 to an
inlet duct 144 leading into the second separator 134
25 which is located vertically above the ultimate collection
site. A single duct 140 connects the material discharge
outlet from the first separator 132 to the inlet 144 of
the second separator 134. An exhaust air stream exits
from the second separator 134 through an air exhaust
30 conduit 142 and is recycled as one of several input
streams to the first separator 132. In the illustrated
embodiment, the first separator 132 receives a plurality
of air input streams 150, 151, 152, 153, 154, and 155.
In the tangential separating system 130 for
35 separating and accumulating airborne material, the two
separators 132, 134 each operate in generally the same
manner as the separator described with reference to FIGS.
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1-6 and to FIGS. 7-9; however, the system couples the two
separators in a loop arrangement. Various features of
the separators 132, 134 that are common to those
previously described are not repeated in detail
5 hereinafter.
The separator 132 serves as the primary
separator and receives six distinct input streams via
ducts 150, 151, 152, 153, 154, 155 which converge into a
single inlet manifold duct 158 that tangentially
10 discharges into a generally cylindrical primary
separating chamber 16C. As shown in FIG. 11, each duct,
such as duct 154, may include a final section 154a
downstream of a blower. The primary separator 132
includes a compartmented outlet plenum downstream of air-
15 separating devices having a plurality of passageways 162,
163, 164, 165, 166 and 167; it is located intermediate of
the separating chamber 160 and an exhaust plenum 168
through which the separated air leaves the vicinity of
the system. The conveyed material is effectively
20 separated from the air stream within the separating
chamber 160 using a bifurcated air separating technique
as hereinbefore described that employs both an air exit
at the arcuate boundary wall and a centrally disposed
tubular air separator located interior of the separating
25 chamber 160. The boundary wall air exit utilizes a
perforated back wall section 170 (FIG. 11) of the
separating chamber 160, and a centrally disposed
perforated metal tube 172 serves to separate additional
air from the material.
30 A major portion of the air carrying the
entrained material exits the separating chamber 160
through the perforated back wall 170 while the material
slides downward along the arcuate perforated wall. The
dimensions of the perforations and cross sectional area
35 of the arcuate perforated wall 170 are selected such that
between about 50% and 75% of the volume of the air stream
entering the separating chamber 160 passes through the
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perforated wall 170, while the formerly entrained
material stays within the separating chamber 160. An
additional portion of the air which enters the chamber
exits through the centrally disposed perforated tube 172,
5 and the size of the perforations are again chosen to
separate a desired additional amount of the remaining air
from the material. The formerly entrained material exits
the separating chamber 160 through the bottom material
outlet 138.
10 The air which is separated through the back
wall 170 exits from the separating chamber 160
immediately enters a plurality of air exhaust passageways
162, 163, 164 and 165 (FIG. 10) which are formed by
vertical partitions 171 in an exhaust chamber 173; these
15 passageways lead to chamber 200 that empties into the
exhaust plenum 168. the two outermost air exhaust
passageways 166 and 167 in the chamber 173 are in
communication with the opposite ends of the perforated
tube 172 and likewise lead to the chamber 200. If
20 filters are disposed in the exhaust plenum 168, dust
which may accumulate on such filters and fall therefrom
may be collected in a chute at the bottom of the plenum
168 and advantageously transported via a third relay
blower 174 (FIG. 11) and connecting conduit 176 to the
25 material discharge outlet 138 of the primary separator.
As best seen in FIG. 11, the main relay blower
139 is disposed below and offset from the material outlet
138 of the primary separator 132 with which it is in
communication via a curved chute 177. The main relay
30 blower 139 transports the discharged material at a
relatively low velocity via a relay conduit 180 to the
inlet 140 which is tangentially disposed at the top of
the generally< cylindrical secondary separator 134 (see
FIG. 12). The secondary separator 134 includes a
35 generally cylindrical separating chamber within a hollow
casing 184 with the material discharge outlet 136 being
located at the bottom of the casing 184. The separator
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134 is essentially the same as the separator 84 shown in
FIGS. 7-9. The separated air exiting the secondary
separator 134 via the combined air exhaust conduit 142 is
transported through the return air duct 150 (FIG. 10),
driven by a blower 189 which discharges to an inlet duct
150a that connects to the inlet plenum 158 of the primary
separator 132.
The conveyed material relayed from the primary
separator 132 to the secondary separator 134 is separated
from the relay air stream within the casing 184 of the
secondary separator 132 with the separated air passing
through a perforated arcuate rear boundary wall 192 and
through a centrally disposed perforated tube 194, as
explained with regard to the separator 84. The material
exits the secondary separator 134 via the bottom material
discharge outlet 136 and falls through a feed chute 196
to the hopper of a horizontal compactor or automatic
baler 198.
The loop arrangement of the illustrated
separating system 130 functions to eliminate the usual
problem of dust in the vicinity of the baler 198 as a
result of the very low static pressure at the material
discharge outlet 136 of the secondary separator 134. For
example, in a prototype separating system similar to the
embodiment described wherein a pair of separators, each
having such dual air exits, which are interconnected in
such a loop configuration was operated so as to move a
total air volume of about 46,000 cubic feet per minute,
the static air pressure (gauge) in the feed chute was
only 0.8 inch of water. This represents a significant
further improvement compared to a single dual air exit
separator operating as a part of a stand-alone separator
system at a caomparable volumetric air flow, which itself
is improved over present commercial systems.
Still another advantage of the separating
system 130 is realized by partitioning to create a
plurality of individual air passageways leading to the
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chamber 200 which communicates with the air exhaust
plenum 168. This partitioning creates the plurality of
parallel passageways which function as compartments which
can be individually closed off. The conduit partitioning
5 arrangement is best described in conjunction with the
illustrations of FIGS. 10, 13 and 14.
The chamber 200 is formed by a shallow
rectangular-shaped duct 202 that contains short vertical
dividers 204 that align with the partitions 171 that
10 create the six separate passageways 162 through 167 shown
in FIG. 10. The duct 202 which forms the chamber 200
preferably includes an access door 208 in each side wall,
which door carries a pair of viewing ports 209.
The shallow duct 202 is fabricated to carry a
15 damper mechanism 210 that includes a plurality of damper
blades 224 that are adapted to open and close each of the
passageways 162-167. The damper blades 224 are attached
to elongated shafts 225 that are journaled in the upper
and lower walls of the duct 202. A clevis and swivel
20 bracket assembly 226 is connected to the upper end of
each shaft 225 for opening and closing the dampers. When
oriented in the closed position, as shown in FIG. 13, the
damper blade 224 in each passageway extends laterally
between two dividers 204 which extend the passageways
25 formed by the partitions 171, blocking and closing that
passageway. Conversely, when the damper blade 224
associated with a passageway is rotated 90° to the open
position, the damper blade 224 is aligned parallel to the
partitions 171 and allows free flow of air therethrough.
30 The actuating mechanism for opening and closing
the damper blades 224 includes an air cylinder assembly
230 which is mounted on the top surface of the duct 202
and is connected at one end to the clevis and swivel
bracket assembly 226 and at the other end to an
35 upstanding bracket or backstop 232. The assembly 230 may
include an air cylinder having a 2" bore and 4" stroke
that is operated under the control of an external control
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unit. In the preferred method of operation, the air
cylinder assemblies are actuated so that five of the six
passageways always remain open, sequentially closing off
only one of the six passageways (162 through 167) at any
5 given time. As soon as the damper blade 224 for any one
passageway is closed, a compressed air blast is
introduced into the closed passageway upstream of the
damper through a nozzle (not shown) to create.a strong
reverse flow of air in that passageway through the air
10 exhaust conduit which cleans the associated section of
the perforated arcuate outer wall 170 or perforated tube
172 of dust or any accumulated scrap material. The
compartmentation of the exhaust chamber 173 permits the
closing of one passageway at a time to cyclicly effect
15 the cleaning thereof ~~ithout affecting the remainder, so
that there is no need to shut down the separating
operation for cleaning. While one passageway is being
closed to clean a section of the perforated arcuate outer
wall 170 or of the perforated tube 172, the other
20 passageways of the air exhaust chamber remain open and
operative, serving to permit the free flow of air being
separated in the separating chamber, as described above.
In this manner, the perforated arcuate outer wall 170 and
perforated metal tube 172 can be sequentially cleared of
25 accumulating material without halting the continuous
material separating operation.
From the foregoing, it should be appreciated
that the present invention thus provides an improved
method and apparatus for separator material entrained in
30 a stream of air or sirc~ilar transport medium. Further, it
will be apparent that various changes may be made in the
form, construction and arrangement of the parts thereof
without departing from the spirit and scope of the
invention or sacrificing all of its material advantages,
35 the forms hereinbefore described being merely exemplary
embodiments thereof. Therefore, it is not intended that
the scope of the invention be limited to the specific
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embodiments and processes described. Rather, it is
intended that the scope of this invention be determined
by the appending claims and their equivalents.
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