Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF INVENTION
Shaft Seal Assembly
CROSS REFERENCE TO RELATED APPLICATIONS
Applicant states that this utility patent application is a continuation-in-
part of and claims priority
from U.S. Pat. App. No. 13/219,894 filed on 08/29/2011, which application is a
continuation of
and claims priority from U.S. Pat. App. No. 12/763,771 filed on 04/20/2010,
which application is
a continuation of and claimed priority from U.S. Pat. App. No. 12/397,775
filed on 03/04/2009
(now U.S. Pat. No. 7,726,661), which application was a continuation-in-part of
and claimed
priority from U.S. Pat. App. No. 12/156,476 filed on 05/30/2008 (now U.S. Pat.
No. 7,631,878),
which application was a continuation of and claimed priority from U.S. Pat.
App. No.
11/405,207 filed on 04/17/2006 (now U.S. Pat. No. 7,396,017), which
application was a
continuation-in-part of and claimed priority from U.S. Pat. App. No.
10/177,067 filed on
06/21/2002 (now U.S. Pat. No. 7,090,403) also claimed priority from
provisional Pat. App. No.
60/697,434 filed on 07/09/2005, all of which are incorporated by reference
herein in their
entireties. This utility patent application also claims priority from
provisional Pat. App. Nos.
61/659,714 filed on 06/14/2012 and 61/661,936 filed on 06/20/2012, both of
which are
incorporated by reference herein in their entireties.
FIELD OF THE INVENTION
The present invention relates to a shaft seal assembly with multiple
embodiments. In certain
embodiments, the shaft seal assembly may be used as a product seal between a
product vessel
and a shaft therein.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR
DEVELOPMENT
No federal funds were used to create or develop the invention herein.
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM
LISTING COMPACT DISK APPENDIX
N/A
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BACKGROUND OF THE INVENTION
For years there have been a multitude of attempts and ideas for providing a
satisfactory seal
when a rotatable shaft is angularly misaligned resulting in run out of the
shaft. Typically the
solutions presented have failed to provide an adequate seal while allowing for
an acceptable
amount of shaft misalignment during operation. The problem is especially acute
in product seals
where the potential for shaft to bore misalignment may be maximized. A typical
solution in the
prior art is to increase the operating clearance between the rotating shaft
and sealing members to
create a "loose" clearance or operating condition. "Loose" running for
adjustment or response to
operational conditions, especially misalignment of the shaft with respect to
the stator or
stationary member, however, typically reduces or lowers the efficiency and
efficacy of sealing
members.
Labyrinth seals, for example, have been in common use for many years for
application to sealing
rotatable shafts. A few of the advantages of labyrinth seals over contact
seals are increased wear
resistance, extended operating life and reduced power consumption during use.
Labyrinth seals,
however, also depend on a close and defined clearance with the rotatable shaft
for proper
function. Shaft misalignment is also a problem with "contact" seals because
the contact between
the seal and misaligned shaft typically results in greater wear. Abrasiveness
of the product also
affects the wear pattern and the useful life of the contact seals.
Prior attempts to use fluid pressure (either vapor or liquid) to seal both
liquid and solid materials
in combination with sealing members such as labyrinth seals or contact seals
have not been
entirely satisfactory because of the "tight" or low clearance necessary to
create the required
pressure differential between the seal and the product on the other side of
the seal (i.e., the tighter
the seal, the lower the volume of fluid required to maintain the seal against
the external pressure
of material.) Another weakness in the prior art is that many product seals
expose the movable
intermeshed sealing faces or surfaces of the product seal to the product
resulting in aggressive
wear and poor reliability. Furthermore, for certain applications, the product
seal may need to be
removed entirely from the shaft seal assembly for cleaning, because of product
exposure to the
sealing faces or surfaces.
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The prior art then has failed to provide a solution that allows both a "tight"
running clearance
between the seal members and the stationary member for efficacious sealing and
a "loose"
running clearance for adjustment or response to operational conditions
especially misalignment
of the rotatable shaft with respect to the stator or stationary member.
SUMMARY OF THE INVENTION
The present art offers improved shaft sealing and product seal performance
over the prior art.
The shaft seal assembly solution disclosed and claimed herein allows both
tight or low running
clearance between seal members and the stationary member and a loose running
clearance for
adjustment or response to operational conditions especially misalignment of a
rotatable shaft
with respect to the stator or stationary member.
As disclosed herein, the present art describes and provides for improved
function by allowing a
labyrinth seal to adjust to radial, axial and angular movements of the shaft
while maintaining a
desired shaft-to-labyrinth clearance. The present art also permits
equalization of pressure across
the labyrinth pattern by permitting venting and thus improved function over
currently available
designs. Additionally, sealing fluid (air, steam, gas or liquid) pressure may
be applied through
the vent or port locations to establish an internal seal pressure greater than
inboard or outboard
pressure (over-pressurization). This enables the labyrinth to seal pressure
differentials that may
exist between the inboard and outboard sides of the seal. Pressurization of
the internal portion of
the shaft seal assembly effectively isolates the moving or engaging faces of
the shaft seal
assembly from contact with product by design and in combination with a
pressurized fluid
barrier.
It is therefore an object of the present invention to provide a shaft seal
assembly for engagement
with a housing which maintains its sealing integrity with a shaft upon
application of axial,
angular or radial force upon said shaft.
It is another object of the present invention to provide a shaft seal assembly
that may be mounted
to a vessel wall for engagement with a shaft which maintains its sealing
integrity with a shaft
during or in response to axial, angular or radial force movement of said
shaft.
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Other objects and features of the invention will become apparent from the
following detailed
description when read with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the advantages of the invention will be readily understood, a
more particular
description of the invention briefly described above will be rendered by
reference to specific
embodiments illustrated in the appended drawings. Understanding that these
drawings depict
only typical embodiments of the invention and are not therefore to be
considered limited of its
scope, the invention will be described and explained with additional
specificity and detail
through the use of the accompanying drawings.
FIG. 1 is a perspective exterior view of the shaft seal assembly.
FIG. 2 is an exterior end view of the shaft seal assembly with the shaft
element aligned.
FIG. 3 is a sectional view of a first embodiment of the shaft seal assembly,
as shown in FIG. 2
and mounted to a housing.
FIG. 3A illustrates the first surface seal-shaft integrity during angular and
radial shaft alignment.
FIG. 3B illustrates second surface seal-shaft integrity during angular and
radial shaft alignment.
FIG. 4 is an exterior end view with the shaft misaligned.
FIG. 5 is a sectional view of the first embodiment as shown in FIG. 3 with
both angular and
radial misalignment of the shaft applied.
FIG. 5A illustrates first seal-shaft integrity allowed by articulation during
angular and radial
shaft misalignment.
FIG. 5B illustrates second seal-shaft integrity allowed by articulation during
angular and radial
shaft misalignment.
FIG. 6 is a sectional view of a second embodiment of the shaft seal assembly
as shown in FIG. 2.
FIG. 7 is a sectional view of a third embodiment as shown in FIG. 2.
FIG. 8 is a perspective view of a fourth embodiment as mounted to a vessel
wall.
FIG. 9 is a cross-sectional of view of one embodiment of the shaft seal
assembly with the shaft
aligned with respect to the housing.
FIG. 10 is a cross-sectional view of another embodiment of the shaft seal
assembly with the shaft
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aligned with respect to the housing.
FIG. 11 is a cross-sectional view of the embodiment shown in FIG. 10 with the
shaft misaligned
with respect to the housing.
FIG. 12 is a cross-sectional view of the embodiment shown in FIG. 9 of the
invention showing
the shaft misaligned with respect to the housing.
FIG. 13 is a cross-sectional view of the embodiment shown in FIG. 9 showing
the shaft
misaligned with respect to the housing.
FIG. 14 is a cross-sectional view of a third embodiment of the shaft seal
assembly.
FIG. 14A is a detailed cross-sectional view of the interface between the rotor
and the shaft of the
third embodiment of the shaft seal assembly.
FIG. 15 is a perspective view of a first embodiment of a multi-shaft seal
assembly.
FIG. 15A is a perspective view of the embodiment of a multi-shaft seal
assembly shown in FIG.
15 with the second seal removed for clarity.
FIG. 15B is a rear perspective view of the embodiment of a multi-shaft seal
assembly shown in
FIG. 15.
FIG. 16 is a plane vertical view of the embodiment shown in FIG. 15.
FIG. 17 is an axial, cross-sectional view of one of the seals shown in the
embodiment in FIG. 15.
FIG. 18A is a perspective view of another embodiment of a shaft seal assembly.
FIG. 18B is an axial, cross-sectional view of the embodiment of a shaft seal
assembly shown in
FIG. 18A.
FIG. 18C is an axial, exploded cross-sectional view of the embodiment of a
shaft seal assembly
shown in FIG. 18A.
FIG. 18D is a detailed cross-sectional view of the embodiment of a shaft seal
assembly shown in
FIGS. 18A-18C wherein the shaft is vertically oriented.
DETAILED DESCRIPTION¨ELEMENT LISTING (FIGS. 1-8)
Description Element No.
Shaft 1
Fixed stator 2
Fixed stator (part-line) 2a
Labyrinth seal 3
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Radiused face 3a
Floating stator 4
Fluid return pathway 5
Shaft seal clearance 6
First o-ring 7
Anti-rotation pin 8
Vent 9
Anti-rotation groove (floating stator) 10
Spherical interface 11
Anti-rotation pin 12
Second o-ring 13
Labyrinth seal pattern grooves 14
First o-ring channel 15
Cavity for anti-rotation device (fixed stator) 16
Axial face of labyrinth seal 17
Axial face of floating stator 18
Second o-ring channel 19
First clearance between floating stator/fixed stator 20
Second clearance between floating stator/fixed stator 21
Throttle groove 22
Labyrinth pattern annular groove 23
Sleeve 24
Shaft seal assembly 25
Throttle (alignment skate) 26
Floating stator annular groove 27
Labyrinth seal passage 28
Floating stator passage 29
Housing 30
Angle of misalignment 31
Bearings and bearing cavity 32
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Mounting bolts 33
Vessel wall 34
DETAILED DESCRIPTION
Before the various embodiments of the present invention are explained in
detail, it is to be
understood that the invention is not limited in its application to the details
of construction and the
arrangements of components set forth in the following description or
illustrated in the drawings.
The invention is capable of other embodiments and of being practiced or of
being carried out in
various ways. Also, it is to be understood that phraseology and terminology
used herein with
reference to device or element orientation (such as, for example, terms like
"front", "back", "up",
"down", "top", "bottom", and the like) are only used to simplify description
of the present
invention, and do not alone indicate or imply that the device or element
referred to must have a
particular orientation. In addition, terms such as "first", "second", and
"third" are used herein and
in the appended claims for purposes of description and are not intended to
indicate or imply
relative importance or significance.
Figures 1-5 provide a view of a first embodiment of the shaft seal assembly 25
that allows for
sealing various lubricating solutions within bearing housing 30. Figures 6 and
7 provide
alternative embodiments of the shaft seal assembly 25 wherein sealing fluids
are used. Applicant
herein defines sealing fluids to include both liquids and vapors. Applicant
considers air, nitrogen,
water and steam as well as any other fluid which may work with the proposed
shaft seal
assembly to provide a pressurized fluid barrier for any and all embodiments
disclosed herein to
be within the purview of the present disclosure. The gas or fluid chosen is
based on process
suitability with the product to be sealed.
Figure 1 is a perspective exterior view of the shaft seal assembly 25 arranged
and engaged with a
shaft 1 inserted through the fixed stator 2 of shaft seal assembly 25. Figure
2 is an exterior end
view of the shaft seal assembly with shaft 1 aligned within the shaft seal
assembly 25.
Figure 3 is a sectional view of a first embodiment of the shaft seal assembly
25 shown in Figure
2 illustrating the shaft seal assembly 25 as a labyrinth seal for retaining
lubrication solution
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within the bearing cavity 32 of housing 30. The shaft 1 shown in Figure 3 is
the type which may
experience radial, angular or axial movement relative to the fixed stator
element or portion of the
fixed stator 2 during rotation. The fixed stator portion of the shaft seal
assembly 25 may be
flange-mounted or press-fit or attached by other means to a housing 30. The
invention will also
function with a rotating housing and stationary shaft. (Not shown) As required
by the particular
application, the shaft 1 is allowed to move freely in the axial direction in
relation to the shaft seal
assembly 25.
A labyrinth seal 3 having an interior surface is engaged with shaft 1. A
defined clearance 6 exists
between the interior surface of said labyrinth seal 3 and the shaft 1.
Opposite the interior surface
of said labyrinth seal 3 is the radiused surface 3a of said labyrinth seal 3.
The radiused surface 3a
of the labyrinth seal 3 and the interior of the floating stator 4 forms a
spherical interface 11. 0-
ring channels 15 and o-rings 7 are disposed to cooperate with said radiused
surface 3a of said
labyrinth seal 3 to seal (or trap) fluid migration through, between and along
engaged labyrinth
seal 3 and floating stator 4 while maintaining spherical interface 11 which
allows limited relative
rotational movement (articulation) between labyrinth seal 3 and floating
stator 4. 0-ring channels
15, as shown, are machined into the floating stator 4 and positioned at the
spherical interface 11
with labyrinth seal 3. 0-ring channels 15 are annular and continuous in
relation to labyrinth seal
3. The o-ring channel 15 and o-ring 7 may also be placed in the labyrinth seal
3 adjacent the
spherical interface 11. 0-rings 7 should be made of materials that are
compatible with both the
product to be sealed and the preferred sealing fluid chosen. 0-ring channels
15 and o-rings 7 are
one possible combination of sealing means that may be used within the shaft
seal assembly 25 as
recited in the claims. Strategically placed anti-rotation pin(s) 12 inserted
into anti-rotation
grooves 10 limit relative rotational movement between labyrinth seal 3 and
floating stator 4. A
plurality of anti-rotation grooves 10 and pins 12 may be placed around the
radius of the shaft 1.
If the shaft seal assembly 25 is used in combination with a sealing fluid,
strategic anti-rotation
pins 12 may be removed allowing corresponding anti-rotation grooves 10 to
serve as a fluid
passage through vent 9 and lubricant return 5. (See Figure 7) Additionally,
the relationship of the
diameters of anti-rotation pins 12 and anti-rotation grooves 10 may be
selected to allow more or
less angular misalignment of the shaft 1. A small diameter anti-rotation pin
12 used with a large
diameter anti-rotation groove 10 would allow for greater relative movement of
the labyrinth seal
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3 in relation to the floating stator 4 in response to angular misalignment of
shaft 1. Labyrinth seal
3 is one possible embodiment of a sealing means that may be used adjacent to
the shaft 1 within
the shaft seal assembly 25 as recited in the claims.
A continuous annular channel is formed within fixed stator 2 and defined by
clearance 20 and 21
as allowed between the exterior of said floating stator 4 and said interior of
said fixed stator 2 of
shaft seal assembly 25. The annular channel of fixed stator 2 is highlighted
as A-A' in Figure 2.
The annular channel of the fixed stator has interior surfaces which are
substantially
perpendicular to said shaft 1. The exterior surfaces of the floating stator 4,
which is substantially
encompassed within the annular channel of the fixed stator 2, cooperatively
engage with the first
and second interior perpendicular faces of the fixed stator 2. An inner
annular interface is formed
by the first (shaft seal assembly inboard side) perpendicular annular channel
surface of the fixed
stator 2 engaging with the first (inboard side) perpendicular face of the
floating stator 4. An outer
annular interface is formed by the second (shaft seal assembly outboard side)
perpendicular
annular interior channel surface of the fixed stator 2 engaging with the
second (outboard side)
perpendicular face of the floating stator 4. 0-ring channels 19 and o-rings 13
disposed therein
cooperate with the surfaces of floating stator 4 which are in perpendicular to
relation to shaft 1 to
sealing (or trap) fluid migration between and along engaged floating stator 4
while allowing
limited relative rotational movement between floating stator 4 and fixed
stator 2. Floating stator
4 and fixed stator 2 are one possible embodiment of cooperatively engaged
sealing means that
may be used in combination with labyrinth seal 3 within the shaft seal
assembly 25 as recited in
the claims.
0-ring channels 19 are annular and continuous in relation to shaft 1. The o-
ring channels 19 and
o-rings 13 may be placed in the body of the floating stator 4 instead of the
fixed stator 2 (not
shown) but must be placed in similar proximal relation. 0-rings 13 should be
made of materials
that are compatible with both the product to be sealed and the preferred
sealing fluid chosen. 0-
ring channels 19 and o-rings 13 are one possible combination of sealing means
that may be used
within the shaft seal assembly 25 as recited in the claims.
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Strategically placed anti-rotation pin(s) 8 inserted into anti-rotation
groove(s) 16 limit both
relative radial and rotational movement between floating stator 4 and interior
side of fixed stator
2. A plurality of anti-rotation grooves 16 and pins 8 may be placed around the
radius of the shaft
1. The relationship of the diameters of anti-rotation pins 8 and anti-rotation
grooves 16 may also
be selected to allow more or less angular misalignment of the shaft. A small
diameter anti-
rotation pin 8 and large diameter fixed stator anti-rotation groove allow for
greater relative
movement of the labyrinth seal 3 in response to angular misalignment of shaft
1.
The labyrinth pattern seal grooves 14 may be pressure equalized by venting
through one or more
vents 9. If so desired, the vents may be supplied with a pressurized sealing
fluid to over-
pressurize the labyrinth area 14 and shaft seal clearance 6 to increase the
efficacy of shaft seal
assembly 25. A spherical interface 11 between the labyrinth seal 3 and the
floating stator 4 allow
for angular misalignment between the shaft 1 and fixed stator 2. 0-ring
channels 19 are annular
with the shaft 1 and, as shown, are machined into the fixed stator 2 and
positioned at the
interface between the fixed stator 2 and floating stator 4. 0-ring channel 19
may also be placed
in the floating stator 4 for sealing contact with the fixed stator 2.
Figure 3A illustrates seal-shaft integrity during angular and radial shaft
alignment. This view
highlights the alignment of the axial face 17 of the labyrinth seal 3 and the
axial face 18 of the
floating stator 4. Particular focus is drawn to the alignment of the axial
faces 17 and 18 at the
spherical interface 11 between the floating stator 4 and labyrinth 3. Figure
3B illustrates the
shaft-seal integrity during angular and radial shaft alignment at the surface
opposite that shown
in Figure 3A. This view highlights the alignment of the axial faces 17 and 18
of labyrinth seal 3
and floating stator 4, respectively, for the opposite portion of the shaft
seal assembly 25 as shown
in Figure 3A. Those practiced in the arts will appreciate that because the
shaft 1 and shaft seal
assembly 25 are of a circular shape and nature, the surfaces are shown 360
degrees around shaft
1. Again, particular focus is drawn to the alignment of the axial faces 17 and
18 at the spherical
interface 11 between the labyrinth seal 3 and floating stator 4. Figure 3A and
3B also illustrate
the first defined clearance 20 between the floating stator 4 and the fixed
stator 2 and the second
defined clearance 21 between the floating stator 4 and fixed stator 2 and
opposite the first
defined clearance 20.
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In Figures 2, 3, 3A and 3B, the shaft 1 is not experiencing radial, angular or
axial movement and
the width of the defined clearances 20 and 21, which are substantially equal,
indicate little
movement or misalignment upon the floating stator 4.
Figure 4 is an exterior end view of the shaft seal assembly 25 with the
rotatable shaft 1
misaligned therein. Figure 5 is a sectional view of the first embodiment of
the shaft seal
assembly 25 as shown in figure 3 with both angular and radial misalignment of
the shaft 1
applied. The shaft 1 as shown in figure 5 is also of the type which may
experience radial, angular
or axial movement relative to the fixed stator 2 portion of the shaft seal
assembly 25.
As shown at figure 5, the defined radial clearance 6 of labyrinth seal 3 with
shaft 1 has been
maintained even though the angle of shaft misalignment 31 has changed. The
shaft 1 is still
allowed to move freely in the axial direction even though the angle of shaft
misalignment 31 has
changed. The arrangement of the shaft seal assembly 25 allows the labyrinth
seal 3 to move with
the floating stator 4 upon introduction of radial movement of said shaft 1.
The labyrinth seal 3
and floating stator 4 are secured together by one or more compressed o-rings
7. Rotation of the
labyrinth seal 3 within the floating stator 4 is prevented by anti-rotation
means which may
include a screws, pins or similar devices 12 to inhibit rotation. Rotation of
the labyrinth seal 3
and floating stator 4 assembly within the fixed stator 2 is prevented by anti-
rotation pins 8. The
pins as shown in figure 3, 3A, 3B, 5, 6 and 7 are one means of preventing
rotation of the
labyrinth seal 3 and floating stator 4, as recited in the claims. Lubricant or
other media to be
sealed by the labyrinth seal 3 may be collected and drained through a series
of one or more
optional drains or lubricant return pathways 5. The labyrinth seal 3 may be
pressure equalized by
venting through one or more vents 9. If so desired, the vents 9 may be
supplied with pressurized
air or other gas or fluid media to over-pressurize the labyrinth seal 3 to
increase seal efficacy.
The combination of close tolerances between the cooperatively engaged
mechanical portions of
the shaft seal assembly 25 and pressurized sealing fluid inhibit product and
contaminate contact
with the internals of the shaft seal assembly 25. The spherical interface 11
between the labyrinth
seal 3 and the floating stator 4 allow for angular misalignment between the
shaft 1 and fixed
stator 2. 0-ring channel 19 and o-ring 13 disposed therein cooperate with the
opposing faces of
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the floating stator 4, which are substantially in perpendicular relation to
shaft 1, to seal (or trap)
fluid migration between and along engaged floating stator 4 while allowing
limited relative
radial (vertical) movement between stator 4 and fixed stator 2.
Figure 5A illustrates seal-shaft integrity allowed by the shaft seal assembly
25 during angular
and radial shaft misalignment. This view highlights the offset or articulation
of the axial faces 17
of the labyrinth seal in relation the axial faces 18 of the floating stator 4
for a first portion of the
shaft seal assembly 25. Particular focus is drawn to the offset of the axial
faces 17 and 18 at the
spherical interface 11 between labyrinth seal 3 and floating stator 4.
Figure 5B illustrates seal-shaft integrity for a second surface, opposite the
first surface shown in
Figure 5A, during angular and radial shaft misalignment. This view highlights
that during
misalignment of shaft 1, axial faces 17 and 18, of the labyrinth seal 3 and
floating stator 4,
respectively, are not aligned but instead move (articulate) in relation to
each other. The shaft to
seal clearance 6 is maintained in response to the shaft misalignment and the
overall seal integrity
is not compromised because the seal integrity of the floating stator 4 to
fixed stator 2 and the
floating stator 4 to labyrinth seal 3 are maintained during shaft
misalignment. Those practiced in
the arts will appreciate that because the shaft 1 and shaft seal assembly 25
are of a circular shape
and nature, the surfaces are shown 360 degrees around shaft 1.
Figure 5A and 5B also illustrate the first clearance or gap 20 between the
floating stator 4 and the
fixed stator 2 and the second clearance or gap 21 between the floating stator
4 and fixed stator 2
and opposite the first clearance or gap 20.
In Figures 4, 5, 5A and 5B, the shaft 1 is experiencing radial, angular or
axial movement during
rotation of the shaft 1 and the width of the gaps or clearances 20 and 21,
have changed in
response to said radial, angular or axial movement. (Compare to Figures 3, 3A
and 3B.) The
change in width of clearance 20 and 21 indicate the floating stator 4 has
moved in response to the
movement or angular misalignment of shaft 1. The shaft seal assembly 25 allows
articulation
between axial faces 17 and 18, maintenance of spherical interface 11 and
radial movement at
first and second clearance, 20 and 21, respectively, while maintaining shaft
seal clearance 6.
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Figure 6 is a sectional view of a second embodiment of the shaft seal assembly
25 as shown in
figure 2 for over-pressurization with alternative labyrinth seal pattern
grooves 14. In this figure
the labyrinth seal pattern grooves 14 are composed of a friction reducing
substance such as
polytetrafluoroethylene (PTFE) that forms a close clearance to the shaft 1.
PTFE is also
sometimes referred to as Teflon which is manufactured and marketed by Dupont.
PTFE is a
plastic with high chemical resistance, low and high temperature capability,
resistance to
weathering, low friction, electrical and thermal insulation, and
"slipperiness." The "slipperiness"
of the material may also be defined as lubricous or adding a lubricous type
quality to the
material. Carbon or other materials may be substituted for PTFE to provide the
necessary sealing
qualities and lubricous qualities for labyrinth seal pattern grooves 14.
Pressurized sealing fluids are supplied to over-pressurize the lubricious
labyrinth pattern 26 as
shown in Figure 6. The pressurized sealing fluids make their way into the
annular groove 23 of
the throttle 26 through one or more inlets. Throttle 26 is also referred to as
"an alignment skate"
by those practiced in the arts. Throttle 26 allows the labyrinth seal 3 to
respond to movement of
the shaft caused by the misalignment of the shaft 1. The pressurized sealing
fluid escapes past
the close clearance formed between the shaft 1 and labyrinth seal 3 having
throttle 26. The close
proximity of the throttle 26 to the shaft 1 also creates resistance to the
sealing fluid flow over the
shaft 1 and causes pressure to build-up inside the annular groove 23. Floating
annular groove 27
in cooperation and connection with annular groove 23 also provides an outlet
for excess sealing
fluid to be "bled" out of shaft seal assembly 25 for pressure equalization or
to maintain a
continuous fluid purge on the shaft sealing assembly 25 during operation. An
advantage afforded
by this aspect of the shaft sealing assembly 25 is its application wherein
"clean-in place" product
seal decontamination procedures are preferred or required. Examples would
include food grade
applications.
Figure 7 illustrates shaft seal assembly 25 with the anti-rotation pin 12
removed to improve
visualization of the inlets. These would typically exist, but are not limited
to, a series of ports,
inlets or passages about the circumference of the shaft seal assembly 25.
Figure 7 also shows the
shape and pattern of the labyrinth seal 3 may be varied. The shape of
throttles 26 may also be
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varied as shown by the square profile shown at throttle groove 22 in addition
to the circular-type
26. Also note that where direct contact with the shaft 1 is not desired, the
shaft seal assembly 25
be used in combination with a separate sleeve 24 that would be attached by
varied means to the
shaft 1.
Figure 8 shows that another embodiment of the present disclosure wherein the
shaft seal
assembly 25 has been affixed to a vessel wall 34. The shaft seal assembly 25
may be affixed to
vessel wall 34 through securement means such as mounting bolts 33 to ensure
improved sealing
wherein shaft 1 is subjected to angular misalignment. The mounting bolts 33
and slots (not
numbered) through the shaft seal assembly 25 exterior are one means of
mounting the shaft seal
assembly 25, as recited in the claims.
ELEMENT LISTING (FIGS. 9-18D)
Description Element No.
Shaft 10
Bearing isolator 18
Housing 19
Rotor 20
Stator 30,31a
Fixed stator 31
Passage 40, 40a
Spherical surface 50, 51
Clearance 52
Frictional seal 60
Flange unit 61a
Center point 80
Conduit 99
Fluid 100
Pin 101
Annular recess 102
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Shaft seal assembly 200
Multi-shaft seal assembly 202
Fastener 204
Aperture 206
Fixed stator 210
Main body 211
Face plate 212
Pin recess 212a
Inlet 214
Annular recess 216
Sealing member 218
Floating stator 220
Radial exterior surface 222
Pin 224
First radial passage 226
Concave surface 228
Rotor 230
Roller cavity 232
Cavity wall 233
Roller 234
Second radial passage 236
Convex surface 238
First seal 240
Collar 241
Collar lip 241a
Collar cutaway 242
Second seal 250
Cutaway 251
Shaft seal assembly 300
0-ring channel 302
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0-ring 303
Unitizing ring 304
Slip ring 305
First cooperating cavity 306a
Second cooperating cavity 306b
Axial passage 307
Radial passage 308
Stator 310
Stator body 311
Shoulder 312
Radial bore 313
Axial projection 314
Radial projection 315
Axial channel 316
Radial channel 317
Unitizing ring channel 318
Rotor 320
Rotor body 321
Rotor axial projection 324
Rotor radial projection 325
Rotor axial channel 326
Rotor radial channel 327
Rotor unitizing ring channel 328
FIG. 9 shows another embodiment of a bearing isolator 18 mounted on a shaft
10. The shaft 10
extends through the bearing isolator 18 and the housing 19. A source of gas or
fluid, 100 which
may include water or lubricant, may also be in communication with the bearing
isolator 18 via
conduit 99. The rotor 20 is affixed to the shaft 10 by means by a frictional
seal 60, which may be
configured as one or more o-rings. The rotor 20 follows the rotational
movement of the shaft 10
because of the frictional engagement of the seals 60. The passages 40 and 40a
are as shown but
will not be described in detail here because such description is already
understood by those
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skilled in the art.
A pair of corresponding spherical surfaces 50 and 51 may be used to create a
self-aligning radial
clearance 52 between the rotor 20 and the stator 30 prior to, during, and
after use. This clearance
52 may be maintained at a constant value even as the shaft 10 becomes
misaligned during use.
Various amounts and direction of misalignment between the centerline of the
shaft 10 and the
housing 19 are illustrated in FIGS. 11-13. An annular recess 102 between the
stator 30 and fixed
stator 31 allows the bearing isolator 18 to accommodate a predetermined amount
of radial shaft
displacement.
In the embodiments shown herein, the spherical surfaces 50, 51 have a center
point identical
from the axial faces of both the rotor and stator 20, 30, respectively.
However, the spherical
surfaces 50, 51 may be radially, and/or as shown, vertically spaced apart.
These spherical
surfaces 50, 51 may move radially in response to and/or in connection with
and/or in concert
with the radially positioning of other components of the bearing isolator 18.
Typically, if the
shaft 10 becomes misaligned with respect to the housing 19, the rotor 20 will
consequently
become misaligned with respect thereto, and then the spherical surfaces 50, 51
and/or the stator
30 moving radially within the annular recess of the fixed stator 31 may
compensate for the
misalignment.
FIGS. 11 and 13 illustrate that in one embodiment of the bearing isolator 18,
the rotor 20 may
move with respect to the stator 30, 31 as shaft 10 is misaligned with respect
to housing 19
through the interaction between spherical surfaces 50, 51 so as to ensure the
distances between
the center points of the rotor 20 and stator 30 and a fixed point on the
housing 19 are constant.
In the embodiment of the bearing isolator 18 shown in FIGS. 10 & 11, the
spherical surfaces 50,
51 may be positioned on a fixed stator 31 and stator 31a rather than on the
rotor 20 and stator 30.
Still referring to FIGS. 10 & 11, this design allows the rotor 20 and stator
31a to move with
respect to the fixed stator 31, flange unit 61a, and housing 19. The rotor 20,
stator 31a, and fixed
stator 31 may move radially with respect to the flange unit 61a (and
consequently with respect to
the housing 19) as best shown in FIG. 11. In this embodiment of the bearing
isolator 18 there is a
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very minimal amount of relative rotation between the spherical surfaces 50,
51.
The embodiment of the bearing isolator 18 shown in FIGS. 10 & 11 may provide
for controlled
radial movement of the fixed stator 31, stator 31a, and rotor 20 with respect
to flange unit 61a,
which flange unit 61a may be securely mounted to a housing 19. Rotational
movement of the
fixed stator 30 with respect to the flange unit 61a may be prevented by anti-
rotational pins 101.
The fixed stator 31 may be frictionally secured to the flange unit 61a using a
frictional seal 61,
which may be made of any material with sufficient elasticity and frictional
characteristics to hold
the fixed stator 31 in a fixed radial position with respect to the flange unit
61a but still be
responsive to the radial forces when the shaft 10 is misaligned. Changes to
the radial position of
the fixed stator 31, stator 31a, and rotor 20 and the resulting positions
thereof (as well as the
resulting position of the interface between the fixed stator 31 and stator
31a) occurs until the
radial force is fully accommodated or unit the maximum radial displacement of
the bearing
isolator 18 is reached.
In operation, the rotor 20 may be moved radially as shaft 10 is misaligned
with respect to the
housing 19. Radial movement of the spherical surfaces 50, 51 between the
stator 31a and fixed
stator may result from this pressure. FIG. 3 shows the resultant radial
movement of center point
80 as the shaft 10 is misaligned. During normal operation, the shaft 10 is
typically horizontal
with respect to the orientation shown in FIG. 3, as represented by line A. As
the shaft 10
becomes misaligned in a manner represented by line B, the center point 80 may
move to a point
along line A". As the shaft 10 becomes misaligned in a manner represented by
line B', the
center point 80 may move to a point along line A'. However, in other shaft 10
misalignments, the
radial positions of the rotor 20, stator 30, and/or fixed stator 31 may be
constant and the spherical
surfaces 50, 51 may compensate for the shaft misalignment. From the preceding
description it
will be apparent that the bearing isolator 18 provides a constant seal around
the shaft 10 because
the distance between the spherical surfaces 50, 51 is maintained as a constant
regardless of shaft
misalignment of a normal or design nature.
The physical dimensions of the spherical surfaces 50 and 51 may vary in linear
value and in
distance from the center point 80, depending on the specific application of
the bearing isolator.
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These variations will be utilized to accommodate different sizes of shafts and
seals and different
amounts of misalignment.
AXIAL DISPLACEMENT SHAFT SEAL ASSEMBLY
Another embodiment of a shaft seal assembly 200 is shown in FIGS. 14 & 14A.
This
embodiment is similar to the embodiment of the bearing isolator 18 described
above and shown
in FIGS. 9, 12, & 13. The shaft seal assembly 200 may include a fixed stator
210, floating stator
220, and a rotor 230, as shown. In the pictured embodiment, the rotor 230
typically rotates with
the shaft 10 while the fixed stator 210 and stator 220 do not. Accordingly, a
rotational interface
may exist between a concave surface 228 of the floating stator 220 and a
convex surface 238 of
the rotor 230. In other embodiments of the shaft seal assembly 200 not
pictured herein, but which
embodiments are a corollary to the embodiment of the bearing isolator 18 shown
in FIGS. 10 &
11, the floating stator 220 may be configured with a convex surface that
corresponds to a
concave surface of the fixed stator. In such an embodiment, the rotational
interface may be
located at a position other than the interface between the concave and convex
surfaces.
The embodiment of the shaft seal assembly 200 shown in FIGS. 14 & 14A includes
a fixed stator
210 that may be securely mounted to a housing (not shown in FIGS. 14 & 14A) my
any suitable
methods and/or structure. The fixed stator 210 may include a main body 211 and
a face plate 212
that may be secured to one another. It is contemplated that a fixed stator 210
formed with a main
body 211 and face plate 212 may facilitate ease of installation of the shaft
seal assembly 200 in
certain applications. In such applications, the main body 211 may be affixed
to the housing, the
rotor 230 and floating stator 220 may be positioned appropriately, and then
the face plate 212
may be secured to the main body 211.
The fixed stator 210 may be formed with an annular recess 216 into which a
portion of the
floating stator 220 and/or rotor 230 may be positioned. A predetermined
clearance between the
radial exterior surface 222 of the floating stator 220 and the interior
surface of the annular recess
216 may be selected to allow for relative radial movement between the fixed
stator 210 and
floating stator 220. At least one pin 224 may be affixed to the floating
stator 220, and a portion
of the pin 224 may extend into a pin recess 212a formed in the face plate 212
so as to prevent the
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floating stator 220 from rotating with the rotor 230. The axial interfaces
between the floating
stator 220 and fixed stator 210 may be sealed with sealing members 218, which
sealing members
may be configured as o-rings.
The floating stator 220 may also be formed with a concave surface 228 in a
radial interior
portion thereof This concave surface 228 may form a semi-spherical interface
with a
corresponding convex surface 238 formed in the radial exterior portion of the
rotor 230.
Accordingly, the shaft seal assembly 200 shown in FIGS. 14 & 14A accommodates
shaft 10
misalignment and radial movement in an identical and/or similar manner to that
previously
described for the bearing isolators 18.
The shaft seal assembly 200 may be configured to accommodate for axial
movement of the shaft
10. In the pictured embodiment this is accomplished by forming at least one
roller cavity 232 in
the rotor 230 adjacent the shaft 10. The illustrative embodiment includes two
roller cavities 232
bound by a cavity wall 233 on either end thereof At least one roller 234 may
be positioned in
each roller cavity 232. Axial movement of the shaft 10 may be accommodated by
a roller 234
rolling along the surface of the shaft 10 and within the roller cavity 232.
The illustrative
embodiment includes two roller cavities 232 with one roller 234 in each roller
cavity 232, but the
shaft seal assembly 200 is in no way limited by the number of roller cavities
232 and/or rollers
234 associated therewith. The roller(s) 234 may be constructed of any suitable
material for the
specific application of the shaft seal assembly 200. It is contemplated that
an elastomeric
material (e.g., rubber, silicon rubber, other polymers) will be especially
suitable for many
applications.
The illustrative embodiment of the shaft seal assembly 200 also includes
various fluid conduits
for applying a sealing fluid to the shaft seal assembly 200. The fixed stator
210 is formed with an
inlet 214 for introduction of a sealing fluid to the shaft seal assembly 200.
The inlet 214 may be
in fluid communication with one or more first radial passages 226 in the
floating stator 220,
which first radial passages 226 may in turn be in fluid communication with one
or more second
radial passages 236 in the rotor 230. The roller(s) 234, roller cavity(ies)
232, and cavity wall(s)
233 may be configured so that the sealing fluid introduced to the inlet 214
exits the shaft seal
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assembly 200 from an area between the rotor 230 and shaft 10 at a
predetermined rate for a given
set of operation parameters (e.g., sealing fluid viscosity and pressure, shaft
10 rpm, etc.). The
illustrative embodiment of the shaft seal assembly 200 may be formed with
eight first radial
passages 226 formed in the floating stator 220, which correspond to eight
second radial passages
236 formed in the rotor 230, and the first radial passages 226 and second
radial passages 236
may be evenly spaced about the circumference of the shaft seal assembly 200.
However, in other
embodiments, different numbers, spacing, and/or configurations of the first
radial passages 226
and/or second radial passages 236 may be used without departing from the
spirit and scope of the
shaft seal assembly 200 as disclosed and claimed herein.
In an embodiment of the shaft seal assembly 200 not pictured herein, but which
embodiment is a
corollary to that shown in FIGS. 10 & 11. It will be apparent in light of the
present disclosure
that in such an embodiment, the rotor 20 will include at least one roller
cavity adjacent the shaft
with at least one roller positioned therein rather than a frictional seal 60.
As with the previous
embodiments of the shaft seal assembly 200 described herein, the roller(s) may
be configured to
rotatively couple the rotor 20 with the shaft 10. The rotor cavity and/or
roller may be also be
configured to allow the shaft 10 to move axially with respect to the shaft
sealing assembly 200.
MULTI-SHAFT SEAL ASSEMBLY
Figure 15 provides a perspective view of a first embodiment a multi-shaft seal
assembly 202. It
is contemplated that a multi-shaft seal assembly 202 may be especially useful
in applications
wherein two shafts 10 are positioned in relative close proximity to one
another, as shown for the
illustrative embodiment pictured herein. The shafts 10 pictured herein are
also oriented such that
the longitudinal axes thereof are parallel with respect to one another.
However, the multi-shaft
seal assembly 202 is not so limited, and other embodiments thereof exist for
use with shafts 10
that are oriented differently than those pictured herein.
The illustrative embodiment of the multi-shaft seal assembly 202 includes a
first seal 240. A
sealing portion of the first seal 240 surrounds one shaft 10 and may be
configured to operate in a
manner substantially similar to other bearing isolators 18 and/or shaft seal
assemblies 25, 200
disclosed herein or otherwise. A sealing portion of a second seal 250
surrounds the other shaft 10
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and also may be configured to operate in a manner substantially similar to
other bearing isolators
18 and/or shaft seal assemblies 25, 200 disclosed herein or otherwise. For
example, FIG. 17
provides an axial, cross-sectional view of a first embodiment of the multi-
shaft seal assembly
202, wherein both the first and second seals 240, 250 are configured to
operate in a manner
substantially similar to the bearing isolator 18 shown in FIGS. 9-13. However,
in other
embodiments of the multi-shaft seal assembly 202, either the first or second
seal 240, 250 may
be differently configured. For example, the first and second seals 240, 250
may be configured
like the embodiment of a shaft seal assembly 200 shown in FIGS. 14 & 14A.
Furthermore, in
other embodiments of the multi-shaft seal 202, the first seal 240 and second
seal 250 may be
configured differently from one another. For example, the first seal 240 may
be configured to
operate in a manner substantially similar to the bearing isolator 18 shown in
FIGS. 9-13 and the
second seal 250 may be configured to operate in a manner substantially similar
to the shaft seal
assembly 200 shown in FIGS. 14 & 14A. Accordingly, the specific internal
configuration of
either the first or second seal 240, 250 in no way limits the scope of the
multi-shaft seal assembly
202 as disclosed herein.
As shown in FIG. 17, each seal 240, 250 may be configured to include a fixed
stator 210,
floating stator 220, face plate 212, and a rotor 220, all of which are shown
in FIG. 17 as being
configured to operate in a manner substantially similar to the embodiment of a
bearing isolator
18 as shown in FIGS. 9-13, as previously mentioned. The rotor 230 may be
secured to a shaft 10
such that the rotor 230 is coupled thereto and rotates therewith in any
suitable manner (several of
which are described above for other embodiments of a bearing isolator 18
and/or shaft seal
assemblies 25, 200). The fixed stator 210 may be secured to a housing 19 in
any suitable manner
(several of which are described above for other embodiments of a bearing
isolator 18 and/or
shaft seal assemblies 25, 200 and which include but are not limited to
mechanical fasteners 204,
chemical adhesives, welding, interference fit, and/or combinations thereof).
One such suitable
manner includes fasteners 204 as shown in FIGS. 15, 16, & 18 and corresponding
apertures 206.
The floating stator 220 may be positioned within a portion of an annular
recess 216 formed in the
fixed stator 10, wherein the exterior axial boundary of the annular recess 216
may be defined by
the interior surface of a face plate 212, which may be engaged with the fixed
stator 210 as
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previously described for other embodiments of the bearing isolator 18 and
shaft seal assemblies
25, 200.
The fixed stator 210, floating stator 220, rotor 230, and/or face plate 212
may cooperate to form
a labyrinth seal. The fixed stator 210, floating stator 220, and/or the rotor
230 may be
constructed in a two-piece manner. As mentioned, in the illustrative
embodiment, the fixed stator
210 may be configured to engage a face plate 212 via a plurality of fasteners
204, which may be
distinct from the fasteners 204 used to engage the fixed stator 210 with the
housing 19. Other
methods and/or structures for engaging the face plate 212 with the fixed
stator 210 may be used
without limitation. Additionally, an interface between two portions of the
rotor 230, two portions
of the fixed stator 210, the fixed stator 210 and the floating stator 220, the
rotor 230 and the
floating stator 220, and/or the rotor 230 and fixed stator 210 may be semi-
spherical, as shown for
the interface between the rotor 230 and floating stator 220 for the embodiment
pictured in FIG.
17. Furthermore, the seals 240, 250 may be formed with an inlet 214 therein,
as previously
described for the other embodiments of a bearing isolator 18 and shaft seal
assemblies 25, 200
disclosed herein to provide a sealing fluid to various passages within the
multi-shaft seal
assembly 202.
To accommodate two shafts 10 in relative close proximity, the illustrative
embodiment of a
multi-shaft seal assembly 202 employs a configuration in which the first and
second seals 240,
250 are configured in a stacked arrangement (see FIGS. 16 & 17). That is, the
first seal 240 may
reside in a different radially oriented plane than that in which the second
seal 250 resides. In the
illustrative embodiment, the planes are parallel with respect to one another.
However, in other
embodiments of the multi-shaft seal assembly 202 not pictured herein, the
planes may have other
orientations, which orientations may be dependent at least in part on the
orientation of the shafts
and/or housing 19.
A collar 241 may be secured to the housing 19 and/or the first seal 240 to
provide the proper
axial spacing for the stacking arrangement of the first and second seals 240,
250. In the
illustrative embodiment the collar 241 may be formed separately from either
the first seal 240 or
the housing 19, and later secured to the first seal 240 and/or housing 19. As
clearly shown in
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FIG. 15B, which provides a rear side perspective view of the illustrative
embodiment of a multi-
shaft seal assembly 202, the collar 241 may be formed with a collar cutaway
242 therein to
accommodate a portion of the second seal 250. As shown, the collar cutaway 242
may be
configured with an angled portion to interface with the exterior surface of
the first seal 240.
In most applications, the surface prominently shown in FIG. 15B is adjacent a
housing 19 during
use of the multi-shaft seal assembly 202. Accordingly, the surface of the
collar 241 and/or first
seal 240 adjacent the housing 19 may be formed with an o-ring channel therein
to accommodate
an o-ring. An o-ring so positioned may serve to prevent air and/or other fluid
from egress/ingress
between the collar 241 and housing 19 and/or between the first seal 240 and
housing 19. The
specific shape, dimensions, and/or configuration of the collar cutaway 242
will vary from one
embodiment of the twin-shaft seal assembly 202 to the next, and may be at
least dependent upon
the spacing of the shafts 10 and/or configuration of the first and second
seals 240, 250, and is
therefore in no way limiting to the scope of the multi-shaft seal assembly
202. As shown for the
illustrative embodiment, the collar 241 may be secured to the housing 19 via
one or more
fasteners 204 and corresponding apertures 206. However, in other embodiments
of the multi-
shaft seal assembly 202 pictured herein, the collar 241 may be integrally
formed with a portion
of the first seal 240. In still other embodiments of the multi-shaft seal
assembly 202 not pictured
herein the collar 241 may be integrally formed with the housing 19. In another
embodiment of a
multi-shaft seal assembly 202 not pictured herein the collar 241 may be
integrally formed with
the second seal 250. Accordingly, the multi-shaft seal assembly 202 is not
limited by the specific
configuration of the first collar 241 with respect to the housing 19, first
seal 240, and/or second
seal 250.
The collar 241 may serve as an axial spacer between the equipment housing and
the second seal
250 as clearly shown in FIGS. 16 & 17. In this embodiment, the axial dimension
of the collar
241 is approximately equal to that of the first and second seals 240, 250.
However, the collar 240
may be formed with a collar lip 241a into which a portion of the second seal
250 may seat, as
shown in FIG. 17. Accordingly, in applications wherein the radial dimension of
the first and/or
second seal 240, 250 is too great for mounting thereof in the same radial
plane due to the spacing
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of two adjacent shafts 10, the first and second seals 240, 250 may be applied
to the shafts 10 in
an axially offset configuration.
The multi-shaft seal assembly 202 may also include a cutaway 251 formed in a
portion of the
second seal 250. A cutaway 251 may be required to accommodate certain
configurations of
adjacent shafts 10 wherein the shafts 10 are in relative close proximity to
one another. As best
shown in FIGS. 16 & 18, the configuration of shafts 10 in the illustrative
embodiment of the
multi-shaft seal assembly 202 are in relatively close proximity to one another
such that the
second seal 250 must be formed with a cutaway 251 to accommodate adequate
clearance with
the shaft 10 corresponding to the first seal 240. However, in other
configurations of adjacent
shafts 10, the multi-shaft seal assembly 202 may not require a cutaway 251.
Accordingly, the
multi-shaft seal assembly 202 is in no way limited the presence, absence,
and/or configuration of
a cutaway 251. Generally, a cutaway 251 may reduce the radial dimension of the
fixed stator 210
and/or face plate 212, as shown in FIG. 17. However, in other configurations
the cutaway 251
may alternatively or additional reduce the radial dimension of the floating
stator 220 and/or rotor
230.
Although the illustrative embodiment of a multi-shaft seal assembly 202 is
configured to
accommodate two shafts 10, other embodiments not pictured herein are
configured to
accommodate more than two shafts 10. Accordingly, the multi-shaft seal
assembly 202 is not
limited by the number of shafts 10 and/or seals 240, 250 associated therewith.
ADDITIONAL EMBODIMENTS OF A SHAFT SEAL ASSEMBLY
Another embodiment of a shaft seal assembly 200 is shown in perspective view
in FIG. 18A. The
illustrative embodiment shown in FIG. 18A includes both a stator 310 and a
rotor 320, which
may rotate with respect to one another. The stator 310 may engage a housing 19
and surround a
shaft 10 that is rotatable with respect to and extends from the housing 19. In
the illustrative
embodiment, an o-ring 303 positioned in an o-ring channel 302 formed in the
stator 310 may be
used to properly engage the stator 310 with the housing 19. However, any other
suitable method
and/or structure for adequately engaging the stator 310 with the housing 19
may be used with the
shaft seal assembly 300 without departing from the spirit and scope as
disclosed herein.
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The rotor 320 may also surround the shaft 10, and it may also be engaged with
the shaft 10 so as
to rotate therewith. In the illustrative embodiment, an o-ring 303 positioned
in an o-ring channel
302 formed in the rotor 320 may be used to properly engage the rotor 320 with
the shaft 10.
However, any other suitable method and/or structure for adequately engaging
the rotor 320 with
the shaft 10 may be used with the shaft seal assembly 300 without departing
from the spirit and
scope as disclosed herein. It is contemplated that this embodiment may be
especially suited for
applications in which the shaft 10 and/or housing 19 is oriented in a
generally vertical
arrangement and extends upward with respect to the housing 19, but the
application of the shaft
seal assembly 300 in no way limits the scope thereof Furthermore, any
embodiments of a shaft
seal assembly 25, 200, 202 may be configured with advantageous features
disclosed herein
related to the embodiment of a shaft seal assembly 300 shown in FIGS. 18A-18D
without
limitation alone or in combination.
The stator 310 may be formed with a stator body 311 having one or more axial
projections 314
and/or radial projections 315 extending therefrom. Additionally, an axial
projection 314 may
extend from a radial projection 315 or vice versa. The embodiment of a shaft
seal assembly 300
from FIG. 18A is shown in FIG. 18C with the stator 310 and rotor 320 separated
from one
another. As shown, a shoulder 312 may be formed in the stator body 311 to
provide an interface
with a housing 19. An o-ring channel 302 may be formed in the shoulder 312 to
accommodate an
o-ring 303 to facilitate proper engagement of the stator 310 and housing 19,
as previously
described above. Another o-ring channel 302 may be formed on the interior
surface of the stator
body 311 adjacent the shaft 10. A slip ring 305 may be positioned in this o-
ring channel 302 to
mitigate egress of lubricant from the housing 19 and ingress of contaminants
to the housing 19
via the space between the shaft 10 and stator 310. In one embodiment, the slip
ring 305 may be
constructed of a low-friction synthetic material, such as PTFE. However, the
specific materials
of construction of the slip ring 305 in no way limit the scope of the present
disclosure. The stator
body 311 may also be formed with one or more radial bores 313 to facilitate an
optional sealing
fluid (e.g., air, water, etc.) to further mitigate the egress and/or ingress
described above.
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The rotor 320 may be formed with a rotor body 321 having one or more rotor
axial projections
324 and/or rotor radial projections 325 extending therefrom. Additionally, a
rotor axial
projection 324 may extend from a rotor radial projection 325 or vice versa. A
unitizing ring 304
may reside partially within a unitizing ring channel 318 formed in the stator
310 and partially
within a rotor unitizing ring channel 328 and function to allow only a
predetermined amount of
relative axial motion between the stator 310 and rotor 320. From a comparison
of FIGS. 18B and
18C, it will be apparent to those of ordinary skill in the art that the
various axial projections 314,
radial projections 315, axial channels 316, and/or radial channels 317 formed
in the stator 310
may cooperate with various rotor axial projections 324, rotor radial
projections 325, rotor axial
channels 326, and/or rotor radial channels 327 to create a labyrinth seal
having a laborious and/or
circuitous path of one or more axial channels 316 and/or one or more radial
channels 317 for
egress of lubricants from the housing 19 and/or ingress of contaminants to the
housing 19. An
infinite number of configurations for the various axial projections 314,
radial projections 315,
axial channels 316, and/or radial channels 317 formed in the stator 310 may
cooperate with
various rotor axial projections 324, rotor radial projections 325, rotor axial
channels 326, and/or
rotor radial channels 327 exist, and accordingly, the specific number,
existence, and/or
configuration thereof in no way limits the scope of the shaft seal assembly
300 as disclosed and
claimed herein.
In the illustrative embodiment of a shaft seal assembly 300 shown herein, the
axial projections
314, radial projections 315, axial channels 316, and/or radial channels 317
formed in the stator
310 may cooperate with various rotor axial projections 324, rotor radial
projections 325, rotor
axial channels 326, and/or rotor radial channels 327 may be configured to form
a first
cooperating cavity 306a, a second cooperating cavity 306b, and an axial
passage 307 for the first
potential ingress point for contaminants. Referring to FIG. 18D, which shows
the illustrative
embodiment of the shaft seal assembly 300 engaged with a generally vertically
oriented shaft 10
protruding upward from a housing 19, the path contaminants must traverse to
pass through the
illustrative embodiment of the shaft seal assembly 300 is exceedingly
tortuous. The only ingress
point is a downwardly oriented terminus of an axial passage 307, entry to
which requires
overcoming gravity. After a radial passage 308, contaminants are faced with
another axial
passage 307 requiring overcoming gravity once again. This axial passage 307
leads to a first
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cooperating cavity 306a. Contaminants retained in the first cooperating cavity
306a may simply
drain downward therefrom via gravity. An axial passage 307 at the top of the
first cooperating
cavity 306a requires contaminants to completely fill the first cooperating
cavity 306a and then
overcome gravity to exit the first cooperating cavity 306a via the top axial
passage 307.
A radial passage 308 may fluidly connect the axial passage 307 at the top of
the first cooperating
cavity 306a to a second cooperating cavity 306b. In the illustrative
embodiment, three sides of
the second cooperating cavity 306b may be formed via the rotor 320, which
generally rotates
with the shaft 10 during use. Accordingly, contaminants reaching the second
cooperating
chamber 306b may be flung radially outward due to centrifugal force imparted
to the
contaminants via rotation of the rotor 320. If contaminants within the second
cooperating
chamber 306b drain via gravity through an axial passage 307 at the bottom of
the second
cooperating chamber 306b, those contaminants must traverse a radial passage
308 prior to
encountering a comparatively long radial passage 308 that leads to another
axial passage 307
adjacent the distal end of an axial projection 314 formed in the stator 310.
Another
comparatively long radial passage 308 may be in fluid communication with the
axial passage 307
adjacent the distal end of an axial projection 314 formed in the stator 310,
the path through
which radial passage 308 may be interrupted by a unitizing ring 304 occupying
a portion of a
unitizing ring channel 318 formed in the stator 310 and a portion of a rotor
unitizing ring channel
328. Should contaminants traverse this radial passage 308, those contaminants
must also traverse
an axial passage 307 in fluid communication with that radial passage 308
before contacting the
shaft 10. To enter the housing 19, contaminants positioned on the shaft 19
between the stator 310
and rotor 320 must traverse a slip ring 305 that, in the illustrative
embodiment of a shaft seal
assembly 300, may be positioned in an o-ring channel 302 in the stator 310
adjacent the shaft 10.
In the illustrative embodiment of the shaft seal assembly 300 pictured herein,
the various
transitions between axial passages 307 and radial passages 308 may be
configured as right
angles. Additionally, all axial passages 307 may be parallel with one another
and perpendicular
to all radial passages 308. However, in other embodiments the axial passages
307 and/or radial
passages 308 may have different orientations without limitation. For example,
in an embodiment
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CA 02876871 2014-12-15
WO 2014/007971 PCT/US2013/045824
not pictured herein, an axial passage 307 may be angled at 45 degrees with
respect to the
rotational axis of the shaft 10.
The materials used to construct the shaft seal assemblies 25, 200, 202, 300
and various elements
thereof will vary depending on the specific application, but it is
contemplated that bronze, brass,
stainless steel, or other non-sparking metals and/or metallic alloys and/or
combinations thereof
will be especially useful for some applications. Accordingly, the above-
referenced elements may
be constructed of any material known to those skilled in the art or later
developed, which
material is appropriate for the specific application of the shaft seal
assembly, without departing
from the spirit and scope of the shaft seal assemblies 25, 200, 202, 300 as
disclosed and claimed
herein.
Having described the preferred embodiments, other features of the shaft seal
assemblies 25, 200,
202, 300 will undoubtedly occur to those versed in the art, as will numerous
modifications and
alterations in the embodiments as illustrated herein, all of which may be
achieved without
departing from the spirit and scope of the shaft seal assemblies 200, 202, 300
disclosed herein.
Accordingly, the methods and embodiments pictured and described herein are for
illustrative
purposes only.
It should be noted that the shaft seal assemblies 25, 200, 202, 300 are not
limited to the specific
embodiments pictured and described herein, but are intended to apply to all
similar apparatuses
and methods for accommodating shaft(s) misalignment with respect to a housing,
whether the
misalignment is angular, radial, and/or axial. Modifications and alterations
from the described
embodiments will occur to those skilled in the art without departure from the
spirit and scope of
the shaft seal assemblies 25, 200, 202, 300.
29
