U.S. patent application number 10/665896 was filed with the patent office on 2005-03-24 for submersible pump.
This patent application is currently assigned to BECKETT CORPORATION. Invention is credited to Kuboshima, Yutaka, Walker, John M..
Application Number | 20050063843 10/665896 |
Document ID | / |
Family ID | 34312966 |
Filed Date | 2005-03-24 |
United States Patent
Application |
20050063843 |
Kind Code |
A1 |
Walker, John M. ; et
al. |
March 24, 2005 |
Submersible pump
Abstract
A motor-driven submersible pump is provided with highly chemical
resistant body parts, a multistage shaft seal including a
self-aligning flexible sheet lip seal, a grounding wire arrangement
to electrically neutralize the environment in which the pump
operates and an improved encapsulation of the motor by epoxy
encapsulation material or the like.
Inventors: |
Walker, John M.; (Grapevine,
TX) ; Kuboshima, Yutaka; (Dallas, TX) |
Correspondence
Address: |
KENNETH R. GLASER
MONIQUE A. VANDER MOLEN
GARDERE WYNNE SEWELL LLP
1601 ELM STREET, SUITE 3000
DALLAS
TX
75201-4761
US
|
Assignee: |
BECKETT CORPORATION
Irving
TX
|
Family ID: |
34312966 |
Appl. No.: |
10/665896 |
Filed: |
September 18, 2003 |
Current U.S.
Class: |
417/423.3 |
Current CPC
Class: |
F04D 13/06 20130101;
F04D 7/06 20130101; F04D 29/106 20130101 |
Class at
Publication: |
417/423.3 |
International
Class: |
F04B 035/04 |
Claims
What is claimed is:
1. A motor-driven pump adapted for being submersed in fluid
comprising: an electric motor disposed in a motor housing, the
motor containing a rotating shaft extending to and supporting an
impeller; a motor cover fitted to the motor housing to enclose the
motor, at least one of the motor housing and the motor cover being
provided with a pour hole through which a non-conductive
encapsulation material may be poured to encapsulate the motor; an
impeller housing that surrounds the impeller and including a fluid
inlet and a fluid discharge conduit for fluid flow; and a
multistage seal disposed between the motor and the impeller that
prevents fluid from contacting the motor.
2. The motor-driven pump of claim 1, wherein the motor cover is
fitted on the motor housing by cooperating latch means.
3. The motor-driven pump of claim 1, wherein the non-conductive
encapsulation material is an epoxy.
4. The motor-driven pump of claim 1, wherein an impeller cover is
secured to the impeller housing with an o-ring disposed
therebetween to prevent fluid from leaking out from within the
interior of the impeller housing.
5. The motor-driven pump of claim 1, wherein a void space is
provided between the impeller and the seal to reduce fluid pressure
build-up on the seal.
6. The motor-driven pump of claim 1, wherein the seal comprises a
self-aligning seal.
7. The motor driven pump of claim 6 wherein: the self-aligning seal
comprises a flexible sheet-like member including an undersize bore
and fitted over the shaft between the impeller and the motor.
8. The motor-driven pump of claim 6, wherein the seal comprises a
lip seal disposed between the self-aligning seal and the motor.
9. The motor-driven pump of claim 8, wherein the seal further
comprises a moisture barrier disposed between the lip seal and the
motor.
10. The motor-driven pump of claim 9, wherein: the moisture barrier
comprises grease packing disposed in a cavity formed in a bracket
member of the motor.
11. The motor-driven pump of claim 1 further comprising electrical
grounding circuit that electrically neutralizes the environment in
which the motor-driven pump operates.
12. The motor-driven pump of claim 11, wherein the grounding
circuit comprises a first ground wire attached to the motor and to
a wall of the motor housing and a second ground wire connected on
one end of a wall of the motor housing and spaced from the
connection of the first ground wire to the motor housing.
13. The motor-driven pump of claim 11, wherein the motor housing is
stainless steel and resistant to fluids that are highly
corrosive.
14. A motor-driven pump capable of being submersed in fluid
comprising: a polymer-encapsulated motor encased in a motor
housing, the motor containing a rotating shaft extending to and
supporting an impeller; a motor cover fitted to the motor housing
to enclose the motor, the motor cover being provided with a pour
hole through which polymer encapsulation material may be poured to
encapsulate the motor; an impeller housing that surrounds the
impeller with an inlet and discharge outlet for fluid flow; and a
multistage seal disposed between the motor cover and the impeller
that prevents fluid from contacting the motor, the multistage seal
comprising a self-aligning first lip seal, a second lip seal
journalled by a member forming part of the motor and a grease
packing moisture barrier.
15. A motor-driven pump adapted for being submersed in fluid
comprising: an electric motor disposed in a motor housing, the
motor containing a rotating shaft extending to and supporting an
impeller; a motor cover fitted to the motor housing to enclose the
motor, at least one of the motor housing and the motor cover being
provided with a pour hole through which a non-conductive
encapsulation material may be poured to encapsulate the motor; an
impeller housing that surrounds the impeller and including a fluid
inlet and a fluid discharge conduit for fluid flow; a multistage
seal disposed between the motor and the impeller that prevents
fluid from contacting the motor, the multistage seal comprising a
self-aligning first lip seal, a second lip seal and a grease
packing moisture barrier; and an electrical grounding circuit that
electrically neutralizes the environment in which the motor-driven
pump operates, wherein the grounding circuit comprises a first
ground wire attached to the motor and to a wall of the motor
housing and a second ground wire connected on one end of a wall of
the motor housing and spaced from the connection of the first
ground wire to the motor housing.
Description
BACKGROUND
[0001] The present invention relates to the general field of
motor-driven pumps, and more particularly to a submersible pump
unit, particularly designed to perform submerged in fluids or
solutions, especially those comprising strong and/or corrosive
chemicals.
[0002] A variety of submersible pumps have been used to perform in
solutions, especially those containing strong chemical solvents.
Unfortunately, prior art motor-driven pumps are often inefficiently
designed and have short life expectancies because the highly
corrosive environments are damaging to the pump body, motor, and/or
seals of the pump. Thus, there is a need for a submersible pump
that operates efficiently while reliably isolating the drive motor
from the fluid in which the pump is submersed. There has further
been a need to develop a pump that is electrically grounded
suitably to prevent galvanic action on the pump components,
including the pump housing. It is to these ends that the present
invention has been developed.
[0003] The present invention addresses many of the needs mentioned
above as well as other objectives that will be appreciated by those
skilled in the art.
SUMMARY OF THE INVENTION
[0004] The present invention solves certain problems associated
with motor-driven pumps that operate submerged in fluid or
solutions, especially those containing strong chemical solvents. A
new and improved motor-driven pump in accordance with the present
invention provides important features including: (1) a highly
chemical resistant body, (2) a shaft seal design for increased seal
reliability and life expectancy of the pump unit; and (3) a
grounding wire arrangement to electrically neutralize the
environment in which the unit operates.
[0005] In accordance with one aspect of the present invention a
motor-driven submersible pump is provided that includes an electric
motor completely encapsulated in insulating and sealing material
within a motor housing, the motor containing a rotating shaft
extending to and drivingly connected to an impeller. The pump
includes a motor cover fitted to the motor housing to enclose the
motor, the motor cover being provided with a pour hole through
which a non-conductive material may be poured to encapsulate the
motor, an impeller housing that surrounds the impeller with an
inlet and discharge outlet for fluid flow, and a seal between the
motor cover and the impeller that prevents fluid from contacting
the motor.
[0006] The present invention also includes an improved shaft seal
arrangement for a pump comprising, a lip seal, a grease packing
space and, in particular, an inexpensive self-aligning seal between
the impeller cavity and a lip seal. The seal arrangement further
includes a grease packing between the lip seal and the pump
motor.
[0007] Those skilled in the art will further appreciate the
above-noted features and advantages of the invention together with
other important aspects thereof. Upon reading the detailed
description which follows in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] For a more complete understanding of the features and
advantages of the present invention, reference is now made to the
detailed description of the invention along with the accompanying
drawing figures in which corresponding numerals in the different
figures refer to corresponding parts and in which:
[0009] FIG. 1 is a perspective view of the pump of the present
invention immersed in a fluid-filled container;
[0010] FIG. 2 is a front end view of the pump of the present
invention;
[0011] FIG. 3 is a side elevation of the pump of the present
invention;
[0012] FIG. 4 is an exploded view of the pump of the present
invention;
[0013] FIG. 5 is a section view taken along line 5-5 of FIG. 2;
[0014] FIG. 6 is a detail section view taken from the same line as
FIG. 5, but of a larger scale; and
[0015] FIG. 7 is a section view taken from line 7-7 of FIG. 5.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Although making and using various embodiments of the present
invention are discussed in detail below, it should be appreciated
that the present invention provides many inventive concepts that
may be embodied in a wide variety of contexts. The specific aspects
and embodiments discussed herein are merely illustrative of ways to
make and use the invention, and do not limit the scope of the
invention.
[0017] In the description which follows like parts are marked
throughout the specification and drawing with the same reference
numerals, respectively. The drawing figures are not necessarily to
scale and certain features may be shown exaggerated in scale or in
somewhat generalized or schematic form in the interest of clarity
and conciseness.
[0018] Additional objects, advantages and novel features of the
invention as set forth in the description, will be apparent to one
skilled in the art after reading the following detailed description
or may be learned by practice of the invention. The objects and
advantages of the invention may be realized and attained by means
of the instruments and combinations particularly pointed out here.
Those skilled in the art will recognize that other modifications
and substitutions may be provided with respect to the invention
disclosed herein without departing from the scope and spirit of the
appended claims
[0019] Referring to FIG. 1, there is illustrated a motor-driven
pump 10 of the present invention submersed in a fluid-filled
container 50. The motor-driven pump 10 comprises a motor housing
12, a motor cover 14, and an electrical conductor fitting 18. The
motor housing 12 may be of a generally rectangular box-like shape
and is preferably formed of a highly chemical resistant material,
such as stainless steel. The motor cover 14 is secured to the motor
housing 12 by cooperating latches 38, two shown in FIG. 1, formed
on the motor cover, placed generally in the center of each of the
four sides of the motor cover and which will be described in
further detail herein. Latches or fingers 38 cooperate with
projections 39, see FIG. 5 also, formed on housing 12 to provide
for snap fitting the motor cover 14 to the housing 12. The
peripheral edge of housing 12 fits in a cooperating groove formed
on motor cover 14, FIG. 5. The motor cover 14 further includes a
generally cylindrical boss 16 and a spaced apart closable pour hole
20 which is closed by a fluid tight cover 62.
[0020] The pump 10 further includes an impeller housing 22, and an
impeller cover 24 including a fluid inlet conduit 26. Housing 22
further includes a fluid discharge conduit 28. Conduit 28 is
preferably connected to a further conduit 28a for delivering fluid
to its end use. The inlet conduit 26 is preferably integral with
the impeller cover 24, while the discharge conduit 28 is integral
with the impeller housing 22. The motor cover 14 and certain other
components, including housing 22 and cover 24 are preferably made
of chemical resistant plastic, such as Acetal. The boss 16 on the
motor cover 14 includes a surface 17, FIG. 5, adjacent which a
gasket 30 lays between the boss 16 and the impeller housing 22. The
impeller cover 24 is preferably affixed to the impeller housing 22
by stainless steel screws 32, at least at three points, as shown,
see FIG. 2 also.
[0021] A jacketed, multi-conductor, electrical power supply cord 40
is attached to motor-driven pump 10 through the fitting 18 to
provide the electrical power for the pump 10. A fluid tight cord
receiving conduit, not shown, may be connected to fitting 18 at
threaded boss 18a. When submerged in the liquid, the motor-driven
pump 10 may be mounted to the fluid-filled container 50 or allowed
to stand alone within the container. Liquid from within the
fluid-filled container 50 enters the pump through a strainer or
screen 52 and the inlet conduit 26, flows through the impeller
housing 22 and out through the discharge conduit 28 which may be
connected to additional conduits, such as conduit 28a shown in FIG.
1.
[0022] Now referring to FIG. 2, there is depicted a front view of
the present invention showing the strainer or screen 52 mounted on
the inlet 26 to prevent foreign particulates from entering the
impeller housing 22. The screen 52 may be formed on a threaded hub
53, releasably secured to inlet conduit 26. Pump 10 may be mounted
on a right angle shaped bracket 54, as shown in FIGS. 1 through 5,
by fasteners 32.
[0023] The electrical supply cord 40 is preferably for supplying
115 Volt, 60 Hertz, power to pump 10. In the preferred embodiment
of the present invention, the electrical supply cord 40 extends
through and is in fluid tight sealing relationship with fitting
18.
[0024] Moreover, the pump drive motor is suitably encased within
the motor housing 12 and is completely isolated from fluid
surrounding the pump or within the impeller housing 22. Further
description of the encasement features is presented below.
[0025] Now referring briefly to FIG. 3, there is depicted a side
view of the motor driven pump 10 of the present invention showing
the optional angle bracket 54 that may be used to mount the pump in
a fluid-filled container, or for other purposes or
arrangements.
[0026] Referring now to FIGS. 4 and 5, FIG. 4 is an exploded view
showing the parts of the pump 10, and FIG. 5 illustrates the parts
assembled, some of which are sectioned. An electric motor 78
provides the motive force for the pump 10 of the present invention.
The motor 78 is disposed within the motor housing 12, and includes
an output shaft 72 drivenly connected to a rotor 80 suitably
supported in opposed bearing housing members 82 and 84. Motor 78
includes conventional, field laminations 81 for rotor 80. Shaft 72
is preferably cylindrical and supports pump impeller 60 thereon,
preferably by an interference fit.
[0027] An improved shaft seal arrangement is provided to protect
the motor 78 encased in the motor housing 12 from fluid moved by
the impeller 60 and within the impeller housing 22. First, the
motor 78 includes a member comprising a generally cylindrical
projection or motor bracket 68 that immediately surrounds the
impeller shaft 72 and projects through a bore 16b, FIGS. 5 and 6,
in snug or press fitted relationship. A cavity 67 in bracket 68 is
packed with a suitable moisture barrier material, such as grease
69, see FIG. 6, also. A fluoroelastomer double lip seal 66, FIGS. 5
and 6, is journalled by the bracket 68 by being disposed snug
fitted in an enlarged bore 71 in the bracket. A flexible sheet-like
self-aligning lip seal 64 is interposed a face 68a of bracket 68
and gasket 30 that abuts a surface 22a of impeller housing 22, FIG.
6. The impeller 60 is disposed within cavity 23 of the impeller
housing 22. The impeller cover 24 is fitted with an o-ring 58
engageable with the impeller housing 22. Plural countersunk screws
35 secure the impeller housing 22 to the motor cover 14, as shown
in FIGS. 5 and 6.
[0028] Motor cover 14 is a generally rectangular member with
generously radiused corners and with a perimeter, depending flange
14f, FIGS. 1 and 5, which defines, in part, a perimeter groove 14g,
FIG. 5, for receiving a perimeter rim 12r of housing 12. Cover 14
includes opposed, resiliently deflectable fingers comprising the
latches 38, FIG. 5, which are of relatively slim width and formed
on opposite sides of cover 14. The fingerlike latches 38 are
engageable with the opposed cooperating inwardly facing projections
39 formed in the side and end walls of housing 12. Motor cover 14
and housing 12 are dimensioned to be snap fitted together in
substantially fluid tight engagement thanks to the latch means
provided by the fingers 38 and projections 39. Motor cover 14 is
further provided with four, opposed, arcuate flanges 14e, FIGS. 4
and 5, which aid in locating and supporting the motor cover with
respect to the housing 12.
[0029] The motor 78 is further protected from fluid by an
encapsulation process. Here, a protective encapsulating material is
caused to flow into the interior space 12s defined by the motor
housing 12 and the motor 78 and to totally encapsulate motor 78.
The protecting encapsulating material, not shown is added through
the pour hole 20. The pour hole 20 is then capped with fitted pour
hole cover 62, secured by adhesive, for example.
[0030] Generally, the encapsulation process includes adding a
non-conductive encapsulating material, such as black epoxy, using
methods known to one of ordinary skill in the art.
[0031] To electrically neutralize the environment in which the
motor-driven pump 10 operates, an improved grounding wire
arrangement is provided in accordance with the present invention.
The generally rectangular box shaped stainless steel motor housing
12 has been incorporated into the grounding design. As shown in
FIGS. 2 and 5, a first ground wire 74 is attached to motor 78, such
as at the bearing housing member 84 of the motor, and includes a
connector 74a which is connected via solder or welding to bottom
wall 12a of the motor housing 12 near the electrical fitting 18. A
second ground wire 76 is also connected to bottom wall 12a of the
motor housing 12 at a connector 76a also near the electrical
fitting 18 but spaced apart from the point of connection of wire 74
to wall 12a, as shown in FIG. 2, and substantially across the width
of housing bottom wall. The second ground wire 76 is included in
the electrical power supply cord 40. This arrangement provides
superior cancellation of galvanic effects on the pump and prevents
exterior portions of the pump e.g., motor housing 12, motor cover
14, pour hole lid 62, external screws, as well as the impeller 60,
seal 66 and screen 52, from deteriorating and/or corroding as a
result of galvanic effects.
[0032] Referring further to FIGS. 5 and 6, there is depicted a
complete assembly view of the present invention, as shown in FIG.
5. FIG. 5 illustrates how the impeller 60 is provided with a
central bore 60b, is fitted in the impeller housing 22 within
cavity 23 and is press fitted onto the impeller shaft 72. FIGS. 6
and 7 illustrate further the configuration of the open style
centrifugal impeller 60, having four equally spaced radial blades
60a. The impeller 60 draws fluid from inlet conduit 26 generally
into the center of the cavity 23 of the impeller housing 22 whereby
fluid is expelled in a radial direction therefrom, exiting out the
discharge outlet 28.
[0033] The multistage seal arrangement in the pump 10 of the
present invention is particularly important in protecting the pump
from failure. As shown in FIGS. 5 and 6, the multistage seal
comprises the self-aligning lip seal 64, formed of a flexible sheet
of, for example, Rulon J, Rulon 123 or Rulon 1045; a
fluoroelastomer double lip seal 66 that may be of a type
commercially available; and a moisture barrier. Self-aligning lip
seal 64 is placed between gasket 30 and the fluoroelastomer seal 66
to self-align with the impeller shaft 72. A moisture barrier 69 is
preferably inserted between the lips of the fluoroelastomer seal 66
and within cavity 67, FIG. 6, of motor bracket 68. Moisture barrier
69 also helps to reduce friction between impeller shaft 72 and the
lips of the fluoroelastomer seal 66. This overall seal arrangement
results in a long life expectancy of motor 78.
[0034] As further shown in FIGS. 5 and 6, a space 23s between the
impeller 60 and backwall 22b of impeller housing 22 functions to
reduce fluid pressure on the self-aligning seal 64 to further
reduce wear and increase its life expectancy. Sheet-like,
self-aligning lip seal 64 includes a slightly undersize bore 64b,
FIG. 6, so that when seal 64 is placed over shaft 72 a
frustoconical lip portion 64a develops which is in substantially
fluid tight engagement with shaft 72 and is disposed generally in a
bore 22c of housing 22. The molding of self-aligning lip seal 64
about the impeller shaft 72 provides an improved seal of proven
long life. In total, the design provides a seal against the
exterior of the rotating shaft. Further, the seals 64 and 66 may be
readily replaced, if required.
[0035] An example of an assembly procedure is further described
herein. For the wiring, the motor housing 12 is placed into an
assembly fixture (e.g., nylon assembly fixture; not shown) followed
by the placement of a threaded electrical conductor fitting 18 into
the motor housing 12. Onto the threaded electrical conductor
fitting 18 an adapter gasket and an adaptor nut is threaded and
tightened. The terminated ends of an electrical supply cord 40 are
placed through the threaded electrical conductor fitting 18 and
into the motor housing 12. The ground lead 76 of the electrical
supply cord 40 is connected to the grounding terminal connector 76a
inside the motor housing 12 (e.g., at the bottom wall 12a) as
further described with FIGS. 2 and 5. The motor cover 14 is press
fit onto the motor 78 at boss 68 (by hand or by machine) and ground
wire 74, which may be previously connected at connector 74a to
motor housing 12, is connected to the motor housing 12, such as at
the bearing housing member 84. The main and common leads of the
electrical supply cord 40 are then connected to the motor 78. Motor
cover 14 is then fitted onto the motor housing 12 (e.g., by hand)
and the unit is then removed from the assembly fixture in
preparation for the encapsulation process.
[0036] For epoxy encapsulation, the pump 10 may be placed on an
epoxy oven conveyor and filled with a non-conducting encapsulation
material, such as black epoxy, through pour hole 20. Additional
epoxy may be dispensed to "top off" the encapsulation process.
After epoxy encapsulation (e.g., epoxy curing), testing of pump 10
may be performed.
[0037] For final assembly of the motor-driven pump 10, a fluid
tight cover 62 is placed (press fit) over pour hole 20. The
flexible sheet-like self-aligning lip seal 64 is pressed over
output shaft 72 and further pressed down until it contacts motor
cover 14. Over the flexible sheet-like self-aligning lip seal 64
and onto the output shaft 72 is placed gasket 30 after which the
impeller housing 22 is placed on the motor cover 14 by inserting
four screws 35 through the impeller housing and onto motor cover
14. The impeller 60 is then pressed onto the output shaft 72 (this
may be performed using a nylon fixture base and an impeller press)
followed by fitting the o-ring 58 engageable with the impeller
housing 22 and securing with impeller cover 24, aligning all holes
for entry of stainless steel screws 32. When optional angle bracket
54 is required, it may be placed over impeller cover 24 aligning
all mounting holes. In either case, screen 52 is further placed
upon impeller cover 24 and formed on a threaded hub 53, releasably
secured to inlet conduit 26.
[0038] Except as otherwise described herein, the pump 10 may be
fabricated using conventional engineering materials and practices
known to those skilled in the art.
[0039] Additional objects, advantages and novel features of the
invention as set forth in the description, will be apparent to one
skilled in the art after reading the foregoing detailed description
or may be learned by practice of the invention. The objects and
advantages of the invention may be realized and attained by means
of the instruments and combinations particularly pointed out
here.
* * * * *