U.S. patent application number 17/379092 was filed with the patent office on 2022-03-31 for mechanical seal including recovery port for use with pumps.
The applicant listed for this patent is Electromechanical Research Laboratories, Inc.. Invention is credited to Stephen P. Wilkins.
Application Number | 20220099103 17/379092 |
Document ID | / |
Family ID | |
Filed Date | 2022-03-31 |
United States Patent
Application |
20220099103 |
Kind Code |
A1 |
Wilkins; Stephen P. |
March 31, 2022 |
Mechanical Seal Including Recovery Port For Use With Pumps
Abstract
A mechanical seal for an axial flow pump may include an annular
seal housing configured to be received in a pump housing, the
annular seal housing defining a shaft aperture configured for
passage therethrough by a pump shaft of the axial flow pump. The
annular seal housing may include a second seal housing face at
least partially defining an annular first seal recess having a
first inner diameter and configured to receive therein an annular
stationary seal, such that the annular stationary seal provides a
stationary seal against the pump shaft, an annular face seal recess
having a second inner diameter greater than the first inner
diameter and configured to receive therein a stationary face seal,
and a recovery port extending from one or more of the first seal
recess or the face seal recess to an exterior of the annular seal
housing.
Inventors: |
Wilkins; Stephen P.; (Floyds
Knobs, IN) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Electromechanical Research Laboratories, Inc. |
New Albany |
IN |
US |
|
|
Appl. No.: |
17/379092 |
Filed: |
July 19, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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63084224 |
Sep 28, 2020 |
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International
Class: |
F04D 29/10 20060101
F04D029/10; F04D 3/00 20060101 F04D003/00 |
Claims
1. A mechanical seal for an axial flow pump, the mechanical seal
comprising: an annular seal housing configured to be received in a
pump housing, the annular seal housing defining a shaft aperture
configured for passage therethrough by a pump shaft of the axial
flow pump, the annular seal housing comprising: a first seal
housing face; a second seal housing face opposite the first seal
housing face and at least partially defining: an annular first seal
recess having a first inner diameter and configured to receive
therein an annular stationary seal, such that the annular
stationary seal provides a stationary seal against the pump shaft;
an annular face seal recess having a second inner diameter greater
than the first inner diameter and configured to receive therein a
stationary face seal; and a recovery port extending from one or
more of the first seal recess or the face seal recess to an
exterior of the annular seal housing; a stationary seal received in
the annular first seal recess; a stationary face seal received in
the annular face seal recess; an inner sleeve coupled to the
annular seal housing and configured to receive therethrough the
pump shaft and rotate with the pump shaft, such that the inner
sleeve rotates relative to the annular seal housing, the inner
sleeve comprising a substantially hollow cylindrical body defining
an internal recess configured to receive therein a shaft seal
configured to abut the pump shaft and rotate with the pump shaft; a
rotating face seal retainer configured to receive therein a
rotating face seal; a rotating face seal received in the rotating
face seal retainer and configured to abut against the stationary
face seal and rotate with the pump shaft, such that the stationary
face seal and the rotating face seal form a sliding seal interface;
and a biasing member positioned to press the rotating face seal
against the stationary face seal.
2. The mechanical seal of claim 1, wherein the recovery port
extends radially outward relative to the one or more of the first
seal recess or the face seal recess.
3. The mechanical seal of claim 1, wherein the recovery port is
positioned such that fluid passing the rotating face seal and the
stationary face seal flows into the recovery port and away from the
mechanical seal.
4. The mechanical seal of claim 1, further comprising a biasing
member retainer radially exterior relative to the biasing member
and extending substantially from a first end of the inner sleeve
toward the rotating face seal.
5. The mechanical seal of claim 4, wherein the inner sleeve is
radially interior relative to the biasing member.
6. The mechanical seal of claim 1, further comprising a preload
spacer longitudinally opposite the biasing member relative to the
seal housing.
7. The mechanical seal of claim 1, further comprising a shaft
collar configured to be coupled to the pump shaft, the shaft collar
being longitudinally opposite the biasing member relative to the
seal housing.
8. The mechanical seal of claim 1, wherein the seal housing further
defines a vent port extending from one or more of the first seal
recess or the face seal recess to the exterior of the annular seal
housing.
9. The mechanical seal of claim 8, wherein the vent port extends
radially outward relative to the one or more of the first seal
recess or the face seal recess.
10. The mechanical seal of claim 1, wherein one or more of the
annular stationary seal or the shaft seal comprises one or more of
an O-ring seal or an energized lip seal.
11. The mechanical seal of claim 1, wherein the recovery port is
configured to be in flow communication with a containment chamber
associated with the axial flow pump, and wherein pressure in the
containment chamber is at a lower pressure than pressure at the
discharge passage of the axial flow pump, thereby creating a
suction pressure at the recovery port.
12. The mechanical seal of claim 1, wherein the annular stationary
seal is configured to provide one or more of a maximum seal
pressure ranging from about 30 pounds per square inch (psi) to
about 75 psi or a minimum pressure ranging from about minus 5 psi
to about minus 40 psi.
13. An axial flow pump and mechanical seal assembly comprising: an
axial flow pump configured to pump fluid, the axial flow pump
comprising: a longitudinal containment chamber; a pump shaft
extending longitudinally within the containment chamber; at least
one pump housing coupled to an entry end of the pump shaft, such
that the pump shaft rotates relative to the at least one pump
housing; at least one impeller coupled to the pump shaft and
configured to rotate with the pump shaft; and a discharge passage
at a discharge end of the axial flow pump opposite the entry end of
the pump shaft; and a mechanical seal coupled to the pump shaft
opposite the entry end of the pump shaft relative to discharge
passage, the mechanical seal comprising: an annular seal housing
received in one of the at least one pump housings, the annular seal
housing defining a shaft aperture through which the pump shaft of
the axial flow pump passes, the annular seal housing comprising: a
first seal housing face; a second seal housing face opposite the
first seal housing face and at least partially defining: an annular
first seal recess having a first inner diameter and configured to
receive therein an annular stationary seal, such that the annular
stationary seal provides a stationary seal against the pump shaft;
an annular face seal recess having a second inner diameter greater
than the first inner diameter and configured to receive therein a
stationary face seal; and a recovery port extending from one or
more of the first seal recess or the face seal recess to an
exterior of the annular seal housing; a stationary seal received in
the annular first seal recess; a stationary face seal received in
the annular face seal recess; an inner sleeve coupled to the
annular seal housing and receiving therethrough the pump shaft and
configured to rotate with the pump shaft, such that the inner
sleeve rotates relative to the annular seal housing, the inner
sleeve comprising a substantially hollow cylindrical body defining
an internal recess configured to receive therein a shaft seal
configured to abut the pump shaft and rotate with the pump shaft; a
rotating face seal retainer configured to receive therein a
rotating face seal; a rotating face seal received in the rotating
face seal retainer and configured to abut against the stationary
face seal and rotate with the pump shaft, such that the stationary
face seal and the rotating face seal form a sliding seal interface;
and a biasing member positioned to press the rotating face seal
against the stationary face seal.
14. The assembly of claim 13, wherein the axial flow pump is
configured to extend downward into a barge interior, the
longitudinal containment chamber defining a port configured to be
coupled to a conduit of the barge to receive therethrough fluid
from the barge interior.
15. The assembly of claim 13, wherein the axial flow pump comprises
a vertical barge pump.
16. The assembly of claim 13, wherein the axial flow pump comprises
a mounting flange configured to be coupled to a support surface of
a barge.
17. The assembly of claim 13, wherein the recovery port provides
fluid flow between the one or more of the first seal recess or the
face seal recess to an interior of the longitudinal containment
chamber of the axial flow pump.
18. The assembly of claim 13, wherein the seal housing further
defines a vent port extending from one or more of the first seal
recess or the face seal recess to the exterior of the annular seal
housing.
19. The assembly of claim 18, wherein the vent port provides fluid
flow between the one or more of the first seal recess or the face
seal recess and the barge interior.
20. The assembly of claim 13, wherein the recovery port extends
radially outward relative to the one or more of the first seal
recess or the face seal recess.
21. The assembly of claim 13, wherein the recovery port is
positioned such that fluid passing the rotating face seal and the
stationary face seal flows into the recovery port and away from the
mechanical seal.
22. The assembly of claim 13, further comprising biasing member
retainer radially exterior relative to the biasing member and
extending substantially from a first end of the inner sleeve toward
the rotating face seal.
23. The assembly of claim 22, wherein the inner sleeve is radially
interior relative to the biasing member.
24. The assembly of claim 13, further comprising a preload spacer
longitudinally opposite the biasing member relative to the seal
housing.
25. The assembly of claim 13, further comprising a shaft collar
coupled to the pump shaft, the shaft collar being longitudinally
opposite the biasing member relative to the seal housing.
26. The assembly of claim 13, wherein the seal housing further
defines a vent port extending from one or more of the first seal
recess or the face seal recess to the exterior of the annular seal
housing.
27. The assembly of claim 26, wherein the vent port extends
radially outward relative to the one or more of the first seal
recess or the face seal recess.
28. The assembly of claim 13, wherein one or more of the annular
stationary seal or the shaft seal comprises one or more of an
O-ring seal or an energized lip seal.
29. The assembly of claim 13, wherein the recovery port is in flow
communication with a containment chamber associated with the axial
flow pump, and wherein pressure in the containment chamber is at a
lower pressure than pressure at the discharge passage of the axial
flow pump, thereby creating a suction pressure at the recovery
port.
30. The assembly of claim 13, wherein the annular stationary seal
is configured to provide one or more of a maximum seal pressure
ranging from about 30 pounds per square inch (psi) to about 75 psi
or a minimum pressure ranging from about minus 5 psi to about minus
40 psi.
Description
PRIORITY CLAIM
[0001] This U.S. non-provisional patent application claims priority
to and the benefit of, under 35 U.S.C. .sctn. 119(e), U.S.
Provisional Application No. 63/084,224, filed Sep. 28, 2020,
"Mechanical Seal Including Recovery Port for Use with Pumps," the
disclosure of which is incorporated herein by reference in its
entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to a mechanical seal for use
with pumps and, more particularly, to a mechanical seal including a
recovery port for use with pumps.
BACKGROUND
[0003] Pumps may be used to transfer a fluid from one receptacle to
another location. For example, a barge may include an interior
cavity, which may include one or more tanks containing a fluid or
fluid-like material for transport via waterways or bodies of water.
Pumps may be used to pump the fluid or fluid-like material from the
one or more tanks into another container for storage or transport
over land. Some pumps may include a pump shaft for driving one or
more impellers to cause flow of the fluid through the pump. The
pump shaft may be rotationally supported by one or more bearings. A
seal may be provided to prevent fluid being pumped from leaking
around the pump shaft. The seal may be prone to leak, particularly
following an extended service period during which internal
components of the seal may wear. Because barges often transport
materials that are not considered environmentally friendly, such as
chemicals and fuels, signs of leakage may result in an
unanticipated need to service or replace a pump seal at remote
locations due to the mobile nature of barges. This may lead to
missed delivery dates, costly off-site repairs, and other
inefficiencies in a cargo transportation operation.
[0004] Accordingly, it may be desirable to provide a seal for pumps
that mitigates or eliminates one or more of the foregoing and other
related or unrelated, issues, and/or problems.
SUMMARY
[0005] In view of the foregoing, in one aspect, the present
disclosure is directed to a mechanical seal for use with pumps and,
more particularly, to a mechanical seal including a recovery port
for use with pumps. In some embodiments, the mechanical seal may
include a recovery port configured to provide a flow path away from
the mechanical seal for fluid passing through the mechanical seal.
The recovery port may be coupled to a fluid line for providing flow
communication between the recovery port and a location away from
the mechanical seal, such as back toward a pump inlet, so that the
fluid may be pumped to a desired location or tank. In some
embodiments, the recovery port may reduce the likelihood or prevent
fluid being pumped by the pump from being released into the
atmosphere or away from the barge.
[0006] According to one aspect, a mechanical seal for an axial flow
pump may include an annular seal housing configured to be received
in a pump housing, the annular seal housing defining a shaft
aperture configured for passage therethrough by a pump shaft of the
axial flow pump. The annular seal housing may include a first seal
housing face and a second seal housing face opposite the first seal
housing face and at least partially defining an annular first seal
recess having a first inner diameter and configured to receive
therein an annular stationary seal, such that the annular
stationary seal provides a stationary seal against the pump shaft.
The second seal housing face may further at least partially define
an annular face seal recess having a second inner diameter greater
than the first inner diameter and configured to receive therein a
stationary face seal. The second seal housing face may also at
least partially define a recovery port extending from one or more
of the first seal recess or the face seal recess to an exterior of
the annular seal housing. The mechanical seal may also include a
stationary seal received in the annular first seal recess and a
stationary face seal received in the annular face seal recess. The
mechanical seal may further include an inner sleeve coupled to the
annular seal housing and configured to receive therethrough the
pump shaft and rotate with the pump shaft, such that the inner
sleeve rotates relative to the annular seal housing. The inner
sleeve may include a substantially hollow cylindrical body defining
an internal recess configured to receive therein a shaft seal
configured to abut the pump shaft and rotate with the pump shaft.
The mechanical seal may still further include a rotating face seal
retainer configured to receive therein a rotating face seal, and a
rotating face seal received in the rotating face seal retainer and
configured to abut against the stationary face seal and rotate with
the pump shaft, such that the stationary face seal and the rotating
face seal form a sliding seal interface. The mechanical seal may
further include a biasing member positioned to press the rotating
face seal against the stationary face seal.
[0007] According to a further aspect, an axial flow pump and
mechanical seal assembly may include an axial flow pump configured
to pump fluid. The axial flow pump may include a longitudinal
containment chamber, and a pump shaft extending longitudinally
within the containment chamber. The axial flow pump may further
include at least one pump housing coupled to an entry end of the
pump shaft, such that the pump shaft rotates relative to the pump
housing. The axial flow pump may also include at least one impeller
coupled to the pump shaft and configured to rotate with the pump
shaft. The axial flow pump may also include a discharge passage at
a discharge end of the axial flow pump opposite the entry end of
the pump shaft. The assembly may further include a mechanical seal
coupled to the pump shaft opposite the entry end of the pump shaft
relative to discharge passage. The mechanical seal may include an
annular seal housing received in a pump housing. The annular seal
housing may define a shaft aperture through which the pump shaft of
the axial flow pump passes. The annular seal housing may include a
first seal housing face and a second seal housing face opposite the
first seal housing face and at least partially defining an annular
first seal recess having a first inner diameter and configured to
receive therein an annular stationary seal, such that the annular
stationary seal provides a stationary seal against the pump shaft.
The second seal housing face may further at least partially define
an annular face seal recess having a second inner diameter greater
than the first inner diameter and configured to receive therein a
stationary face seal. The second seal housing face may still
further at least partially define a recovery port extending from
one or more of the first seal recess or the face seal recess to an
exterior of the annular seal housing. The mechanical seal may
further include a stationary seal received in the annular first
seal recess, and a stationary face seal received in the annular
face seal recess. The mechanical seal may further include an inner
sleeve coupled to the annular seal housing and receiving
therethrough the pump shaft and configured to rotate with the pump
shaft, such that the inner sleeve rotates relative to the annular
seal housing. The inner sleeve may include a substantially hollow
cylindrical body defining an internal recess configured to receive
therein a shaft seal configured to abut the pump shaft and rotate
with the pump shaft. The mechanical seal may also include a
rotating face seal retainer configured to receive therein a
rotating face seal, and a rotating face seal received in the
rotating face seal retainer and configured to abut against the
stationary face seal and rotate with the pump shaft, such that the
stationary face seal and the rotating face seal form a sliding seal
interface. The mechanical seal may further include a biasing member
positioned to press the rotating face seal against the stationary
face seal.
[0008] These and other advantages and aspects of the embodiments of
the disclosure will become apparent and more readily appreciated
from the following detailed description of the embodiments and the
claims, taken in conjunction with the accompanying drawings.
Moreover, it is to be understood that both the foregoing summary of
the disclosure and the following detailed description are exemplary
and intended to provide further explanation without limiting the
scope of the disclosure as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The accompanying drawings, which are included to provide a
further understanding of the embodiments of the present disclosure,
are incorporated in and constitute a part of this specification,
illustrate embodiments of this disclosure, and together with the
detailed description, serve to explain the principles of the
embodiments discussed herein. No attempt is made to show structural
details of this disclosure in more detail than may be necessary for
a fundamental understanding of the exemplary embodiments discussed
herein and the various ways in which they may be practiced.
[0010] FIG. 1 is a schematic perspective view of an example axial
flow pump assembly including an example axial flow pump and example
mechanical seal shown mounted to an example support structure
according to embodiments of the disclosure.
[0011] FIG. 2 is a schematic top view of an axial flow pump
including an example input shaft for coupling to a prime mover to
supply power to the axial flow pump and an example discharge
passage for discharging pumped fluid according to embodiments of
the disclosure.
[0012] FIG. 3 is a schematic side section view showing an example
axial flow pump mounted to an example support structure and showing
example flow paths for fluid pumped by the axial flow pump
according to embodiments of the disclosure.
[0013] FIG. 4 is a partial schematic perspective view showing a
portion of an example axial flow pump including an example
mechanical seal and an example discharge passage for fluid pumped
by the axial flow pump according to embodiments of the
disclosure.
[0014] FIG. 5 is a partial schematic perspective view from a
different angle than FIG. 4 showing a portion of an example axial
flow pump including an example mechanical seal according to
embodiments of the disclosure.
[0015] FIG. 6 is a schematic partial side section view of a portion
of an example axial flow pump including an example mechanical seal
and an example discharge passage for fluid pumped by the axial flow
pump according to embodiments of the disclosure.
[0016] FIG. 7 is a schematic partial side section view of a portion
an example axial flow pump including an example mechanical seal
including an example recovery port and example vent ports according
to embodiments of the disclosure.
DETAILED DESCRIPTION
[0017] The following description is provided as an enabling
teaching of embodiments of this disclosure. Those skilled in the
relevant art will recognize that many changes can be made to the
embodiments described, while still obtaining the beneficial
results. It will also be apparent that some of the desired benefits
of the embodiments described can be obtained by selecting some of
the features of the embodiments without utilizing other features.
Accordingly, those who work in the art will recognize that many
modifications and adaptations to the embodiments described are
possible and may even be desirable in certain circumstances. Thus,
the following description is provided as illustrative of the
principles of the embodiments of the disclosure and not in
limitation thereof, since the scope of the disclosure is defined by
the claims.
[0018] FIG. 1 is a schematic perspective view of an example axial
flow pump assembly 10 including an example axial flow pump 12 and
example mechanical seal 14 shown mounted to an example support
structure 16 according to embodiments of the disclosure. In some
embodiments, the assembly 10 may be mounted on a deck or support of
a waterborne vehicle configured to transport fluid or semi-fluid
materials (e.g., liquid or semi-liquid materials), such as a barge,
and the axial flow pump 12 may be used to pump or transfer fluid
from an interior 18 of the of the waterborne vehicle to another
waterborne vehicle, to a land-borne vehicle, and/or into a
container, such as a tank. In some embodiments, the axial flow pump
14 may include or be a vertical barge pump. As shown in FIG. 1, the
assembly 10 may be mounted to the support structure 16, so that the
axial flow pump 12 extends through a hole 20 in the support
structure 16 and into the interior 18 of the waterborne vehicle. As
shown, some embodiments of the axial flow pump 14 may include a
mounting flange 19 configured to be coupled to the support
structure 16.
[0019] In some embodiments, one or more conduits between one or
more holding tanks in the waterborne vehicle may be coupled to the
axial flow pump 12 to provide fluid flow between the one or more
holding tanks to the axial flow pump 12, so that the fluid or
semi-fluid materials may be transferred from the interior of the
waterborne vehicle to another waterborne vehicle, to a land-borne
vehicle, and/or into a container, for example, as described herein
with respect to FIGS. 2 and 3.
[0020] FIG. 2 is a schematic top view of an axial flow pump 12
including an example input shaft 22 for coupling to an output drive
shaft 24 of a prime mover to supply power to the axial flow pump
12, and an example discharge passage 26 for discharging pumped
fluid according to embodiments of the disclosure. For example, the
prime mover may include one or more of any type of internal
combustion engine (e.g., a diesel engine or spark-ignition engine)
and/or an electric motor configured to generate mechanical power
and torque to drive the input shaft 22 of the axial flow pump 12.
In the example embodiment shown in FIG. 2, the axial flow pump 12
may include a transmission 28 including one or more gears
configured receive power and torque from the input shaft 22
rotating about a first axis X1 and transfer the power and torque to
rotate a pump shaft 30 of the axial flow pump 12, which rotates
about a second axis X2 (see FIG. 3) at an angle relative to the
first axis X1 (e.g., an angle of about ninety degrees).
[0021] FIG. 3 is a schematic side section view showing an example
axial flow pump 12 mounted to an example support structure 16 and
showing example flow paths for fluid pumped by the axial flow pump
12 according to embodiments of the disclosure. As shown in FIG. 3,
in some embodiments, the axial flow pump 12 may include one or more
input ports 32 that may be coupled to one or more conduits 34, for
example, between one or more holding tanks in the waterborne
vehicle. The one or more conduits 34 may be coupled to the one or
more input ports 32 to provide a flow path A into a longitudinal
containment chamber 36 of the axial flow pump 12.
[0022] In the example embodiment shown in FIG. 3, the axial flow
pump 12 may include at least one pump housing 38 coupled to an
entry end 40 of the pump shaft 30, such that the pump shaft 30
rotates relative to the at least one pump housing 38. In some
embodiments, the fluid or semi-fluid material may enter the
containment chamber 36 via the one or more input ports 32 and be
drawn down the containment chamber 36 along a flow path B to the
entry end 40. Once the fluid or semi-fluid material enters the at
least one pump housing 38 at the entry end 40, it may be may be
drawn upward along a flow path C by rotation of one or more
impellers 42 mounted to the pump shaft 30 and driven by the input
shaft 22 (see FIG. 2). Thereafter, the fluid or semi-fluid material
may be discharged via one or more of the discharge passages 26, for
example, at a longitudinal location above the support structure 16,
as shown in FIGS. 3 and 4.
[0023] As shown in FIG. 3, some embodiments of the axial flow pump
12 may include a plurality of pump housings 38, including, for
example, a base housing 38A, a stator housing 38B, one or more
separator housings 38C, and/or one or more impeller housings 38D.
In some embodiments, the axial flow pump 12 may include one or more
stators 44 configured to not rotate with the pump shaft 30, for
example, as shown in FIG. 3. In the example embodiment shown, the
axial flow pump 12 includes two impellers 42A and 42B coupled to
the pump shaft 30 and configured to rotate with the pump shaft 30
and pump fluid or semi-fluid material through the axial flow pump
12 and out the one or more discharge passages 26.
[0024] FIG. 4 is a partial schematic perspective view showing a
portion of an example axial flow pump 12 including an example
mechanical seal 14 and an example discharge passage 26 for fluid
pumped by the axial flow pump 12 according to embodiments of the
disclosure. As shown in FIG. 4, the discharge passage 26 provides
communication for the fluid or semi-fluid material to flow out of
an upper end of the pump housing 38E along a flow path D. As shown
in FIG. 4, the pump shaft 30 extends through the mechanical seal 14
and is coupled to a stabilizer shaft 46 via a shaft coupler 48. The
stabilizer shaft 46 may extend upward through a bearing and may
provide stability to the pump shaft 30 as it rotates.
[0025] As shown in FIGS. 3 and 4, the discharge passage 26 may be
defined by a curved pipe section 50 extending from the upper pump
housing 38E and radially away from the pump shaft 30, with the pump
shaft 30 passing through an aperture 52 in a wall 54 of the pipe
section 50. FIG. 5 is a partial schematic perspective view from a
different angle than FIG. 4 showing the portion of the example
axial flow pump 12, including the example mechanical seal 14, and
FIG. 6 is a schematic partial side section view of the portion of
the example axial flow pump 12 shown in FIGS. 4 and 5.
[0026] As shown in FIGS. 4, 5, and 6, a tubular housing 56 may
extend from an exterior surface of the pipe section 50 and enclose
the aperture 52 in the wall 54 of the pipe section 50, with the
pump shaft 30 extending through the tubular housing 56 and through
the mechanical seal 14. In the example embodiment shown, the
tubular housing 56 is received in an aperture 58 of a radially
extending barrier 60 configured to support the mechanical seal 16,
with an outer circumference 62 of the barrier 60 being coupled to
an interior surface 64 of an outer housing 66. In some embodiments,
for example, as shown in FIGS. 4-7, a seal cap 70 may be provided
to secure the mechanical seal 14 to the barrier 60, for example,
via one or more fasteners (e.g., screws and/or nuts and bolts)
extending through apertures in a housing of the mechanical seal 14
and into or through the barrier 60.
[0027] In some embodiments, as the fluid or semi-fluid materials
are pumped from the discharge passage 26, some of the material may
pass through a clearance 68 between the pump shaft 30 and the
aperture 52 in the wall 54 of the pipe section 50, and into a space
72 partially defined by the tubular housing 56. The mechanical seal
14, in at least some embodiments, may be provided and configured to
prevent (or at least reduce the amount of) the material in the
tubular housing 56 from escaping or otherwise leaking out of the
axial flow pump 12. For example, as shown in FIGS. 4, 5, and 6,
material that passes through and/or around the mechanical seal 14
may collect on top of the barrier 60 in the outer housing 66.
Collection of material at this location, particularly when
excessive, may lead to an unanticipated need to service or replace
the mechanical seal at remote locations, for example, due to the
mobile nature of waterborne vehicles, such as barges.
[0028] FIG. 7 is a schematic partial side section view of a portion
an example axial flow pump 12 including an example mechanical seal
14, including an example recovery port 74 and an example vent port
76, according to embodiments of the disclosure. Although only a
single recovery port 74 is shown in FIGS. 6 and 7, some embodiments
may include more than one recovery port 74. Although FIG. 7 shows
only a single vent port 76, more vent ports 76 are
contemplated.
[0029] As shown in FIG. 7, as explained in more detail herein, some
embodiments of the recovery port 74 may extend radially away from
the mechanical seal 14 and provide a flow path F for material that
passes through the mechanical seal 14 to flow away from the
mechanical seal 14 and reduce or prevent collection of the material
on top of the barrier 66 in the outer housing 66. For example, as
shown in FIGS. 4-7, the recovery port 74 and/or the vent port 76
may be in flow communication with respective fluid lines 78, which
may extend the respective flow paths E and F to a location exterior
to the outer housing 66. In some embodiments, as shown, the fluid
lines 78 may extend back toward the support structure 16, and
provide flow communication with an interior of the containment
chamber 36, for example, via the respective flow paths E and F,
which may allow the material flowing through the fluid lines 78 to
be drawn back into the axial flow pump 14 for discharge through the
discharge passage 26. In some embodiments, pressure in the
containment chamber 36 may be a vacuum pressure or negative
absolute pressure, for example, due to suction of the axial flow
pump 14. As a result, the recovery port 74 and/or the vent port 76
may be subject to a suction pressure, which may assist with
recovery of fluid in flow communication with the recovery port 74
and/or the vent port 76. For example, the recovery port 74 and/or
the vent port 76 may be configured to be in flow communication with
the containment chamber 36, and pressure in the containment chamber
36 may be at a lower pressure than pressure at the discharge
passage 26 of the axial flow pump 14, which may result in a suction
pressure at the recovery port 74 and/or the vent port 76. Other
destinations for the material passing through the fluid lines 78
are contemplated. In this example manner, at least some (e.g., all)
of the material that passes through the mechanical seal 14 may be
carried away from the barrier 66 and the interior of the outer
housing 66. In some embodiments, this may reduce instances of
unanticipated service or replacement of the mechanical seal 14, for
example, when the mechanical seal 14 is leaking material, for
example, due to wear, as explained herein.
[0030] As shown in FIG. 7, in some embodiments, the mechanical seal
14 may be coupled to the pump shaft 30 opposite the entry end 40 of
the pump shaft 30 relative to discharge passage 26. In some
embodiments, the mechanical seal 14 may include an annular seal
housing 80 received in the outer housing 66 of the axial flow pump
12 (e.g., in annular recess 82 of the seal cap 70). In some
embodiments, the annular seal housing 80 may define a shaft
aperture 84 through which the pump shaft 30 of the axial flow pump
14 passes. In some embodiments, the annular seal housing 80 may
include a first seal housing face 86 and a second seal housing face
88 opposite the first seal housing face 86. The second seal housing
face 88 may at least partially define an annular first seal recess
90 having a first inner diameter and configured to receive therein
an annular stationary seal 92, such that the annular stationary
seal 92 provides a stationary seal against the pump shaft 30. In
some embodiments, the annular stationary seal 92 may include an
O-ring seal and/or an energized lip seal (e.g., a lip seal
including a spring). In some embodiments, the stationary seal 92
may be capable of providing a maximum seal pressure ranging from
about 30 pounds per square inch (psi) to about 75 psi (e.g., about
50 psi) and/or a minimum (vacuum) pressure ranging from about minus
5 psi to about minus 40 psi (e.g., about minus 20 psi). As shown in
FIG. 7, the second housing face 88 may also at least partially
define an annular face seal recess 94 having a second inner
diameter greater than the first inner diameter and configured to
receive therein a stationary face seal 96. In some embodiments, the
stationary face seal 96 may be formed from one or more metals,
ceramics, and/or mechanical carbons, such as, for example, silicon
carbide, tungsten carbide, and/or carbon graphite, and may include
a substantially planar annular face configured to contact a
rotating face seal, as explained below. As shown in FIG. 7, the one
or more recovery ports 74 may extend (e.g., radially) from one or
more of the first seal recess 90 or the face seal recess 94 to an
exterior of the annular seal housing 80, for example, as explained
previously herein.
[0031] As shown in FIG. 7, the mechanical seal 14 includes the
stationary seal 92 received in the annular first seal recess 90,
and the stationary face seal 96 is received in the annular face
seal recess 94. In some embodiments, the fit between the stationary
seal 92 and the annular first seal recess 90 is such that the
stationary seal 92 does not rotate with the pump shaft 30. In some
embodiments, the fit between the stationary face seal 96 and the
annular face seal recess 94 is such that the stationary face seal
96 does not rotate with the pump shaft 30.
[0032] As shown in FIG. 7, some embodiments of the mechanical seal
14 may also include an inner sleeve 98 coupled to the annular seal
housing 80 and receiving therethrough the pump shaft 30. In some
embodiments, the fit between an inner diameter of the inner sleeve
98 and the pump shaft may be such that the inner sleeve 98 may
substantially rotate with the pump shaft 30, for example, such that
the inner sleeve 98 rotates relative to the annular seal housing
80. In some embodiments, the inner sleeve 98 may include a
substantially hollow cylindrical body defining an internal recess
100 configured to receive therein a shaft seal 102 (e.g., an O-ring
seal) configured to abut the pump shaft 30 and substantially rotate
with the pump shaft 30.
[0033] As shown in FIG. 7, some embodiments of the mechanical seal
14 may further include a rotating face seal retainer 104 configured
to receive therein a rotating face seal 106. For example, the
rotating face seal 106 may be received in the rotating face seal
retainer 104 and may be configured to abut against the stationary
face seal 96 and substantially rotate with the pump shaft 30, such
that the stationary face seal 96 and the rotating face seal 106
form a sliding seal interface therebetween. For example, the
rotating face seal 106 may be formed from one or more metals,
ceramics, and/or mechanical carbons, such as, for example, silicon
carbide, tungsten carbide, and/or carbon graphite, and may include
a substantially planar annular face configured to contact and slide
relative to a corresponding substantially planar annular face of
the stationary face seal 96, thereby forming a sliding seal
interface 108. The planar annular faces may be formed from a
relatively hardened material and/or a relatively low friction
material to slow wear rates. Through use, however, the planar
annular faces may wear to an extent to which material being pumped
by the axial flow pump 12 may pass or leak through the sliding seal
interface 108 to a point above the barrier 60 and into the outer
housing 66 of the axial flow pump 14. In some embodiments, as
mentioned previously herein, the one or more recovery ports 74 may
reduce or prevent collection of material that passes through the
sliding seal interface 108 (and/or material passing through the
mechanical seal 14 in general) on top of the barrier 60 in the
outer housing 66. In some embodiments, this may reduce the need for
unanticipated service or replacement associated with the mechanical
seal 14, in some instances, prolonging the useful service life of
the mechanical seal 14. As shown in FIG. 7, the mechanical seal 14
may also include a biasing member 110 positioned to press the
rotating face seal 106 against the stationary face seal 96, for
example, to improve the sealing ability of the sliding seal
interface 108.
[0034] As shown in FIG. 7, some embodiments of the mechanical seal
14 may include a biasing member retainer 112 radially exterior
relative to the biasing member 110 and extending substantially from
a first end of the inner sleeve 98 toward the rotating face seal
106. In some embodiments, the inner sleeve 98 may be radially
interior relative to the biasing member 110. The mechanical seal 14
may also include a preload spacer 114 positioned along the pump
shaft 30 longitudinally opposite the biasing member 110 relative to
the seal housing 80. The preload spacer 114 may be configured to
provide a preload urging the stationary face seal 96 and the
rotating face seal 106 against one another, for example, by
partially compressing the biasing member 110, so that the biasing
member 110 provides a force against the rotating face seal 106
toward the stationary face seal 96.
[0035] As shown in FIG. 7, the mechanical seal 14 may also include
a shaft collar 116 coupled to the pump shaft 30 (e.g., via one or
more set screws), for example, to substantially maintain the
longitudinal position of the mechanical seal 14 relative to the
pump shaft 30. The shaft collar 116 may be positioned
longitudinally opposite the biasing member 110 relative to the seal
housing 80.
[0036] The foregoing description generally illustrates and
describes various embodiments of the present disclosure. It will,
however, be understood by those skilled in the art that various
changes and modifications can be made to the above-discussed
construction of the present disclosure without departing from the
spirit and scope of the embodiments as disclosed herein, and that
it is intended that all matter contained in the above description
or shown in the accompanying drawings shall be interpreted as being
illustrative, and not to be taken in a limiting sense. Furthermore,
the scope of the present disclosure shall be construed to cover
various modifications, combinations, additions, alterations, etc.,
above and to the above-described embodiments, which shall be
considered to be within the scope of the present disclosure.
Accordingly, various features and characteristics of the present
disclosure as discussed herein may be selectively interchanged and
applied to other illustrated and non-illustrated embodiments of the
disclosure, and numerous variations, modifications, and additions
further can be made thereto without departing from the spirit and
scope of the present disclosure as set forth in the appended
claims.
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