c12) United States Patent
`Bader et al.
`
`I IIIII IIIIIIII Ill lllll lllll lllll lllll lllll lllll lllll lllll 111111111111111111
`
`US006659737B2
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,659,737 B2
`Dec. 9, 2003
`
`(54) ELECTRONIC FLUID PUMP WITH AN
`ENCAPSUIATED STATOR ASSEMBLY
`
`(75)
`
`Inventors: Mark Bader, Gladstone, MI (US);
`Michael P. Lasecki, Gladstone, MI
`(US); Steven Shiverski, Perronville, MI
`(US); Kenneth A. DeGrave, Wilson,
`MI (US); Jeremy S. Carlson,
`Gladstone, MI (US)
`
`(73) Assignee: Engineered Machined Products, Inc.,
`Escanaba, MI (US)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by O days.
`
`(21) Appl. No.: 09/777,391
`
`(22) Filed:
`
`Feb. 5, 2001
`
`( 65)
`
`Prior Publication Data
`
`US 2002/0106290 Al Aug. 8, 2002
`
`Int. CI.7 ................................................. F04B 39/06
`(51)
`(52) U.S. CI .
`................. 417/366; 417/423.1; 417/423.7;
`417/423.14; 415/211.2; 415/208.2; 415/226;
`415/206
`(58) Field of Search .............................. 417/366, 423.1,
`417/423.7, 423.14; 415/211.2, 208.2, 226,
`206
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`3,559,539 A *
`3,863,935 A *
`3,932,930 A
`5,079,488 A
`
`2/1971 Nagy ... ... .. . .. ... ... ... ... .. . 92/128
`2/1975 Batch .......................... 277/65
`1/1976 Dochterman
`1/1992 Harms et al.
`
`5,096,390 A * 3/1992 Sevrain et al ............... 310/104
`5,344,515 A
`9/1994 Chenock, Jr.
`5,401,146 A
`3/1995 Moriya et al.
`5,474,429 A
`12/1995 Heidelberg et al.
`5,494,413 A
`2/1996 Campen et al.
`5,511,942 A * 4/1996 Meier ...................... 415/211.2
`5,639,227 A * 6/1997 Mills .......................... 417/423
`5,810,568 A
`9/1998 Whitefield et al.
`6,000,915 A
`12/1999 Hartman
`6,012,909 A
`1/2000 Sloteman et al.
`2/2000 Whitefield et al.
`6,030,187 A
`6,056,518 A
`5/2000 Allen et al.
`6,129,524 A * 10/2000 Woollenweber et al. .... 417/366
`6,131,267 A
`10/2000 Van Den Berg
`6,288,470 Bl * 9/2001 Breit .......................... 310/254
`3/2002 Pawelick et al.
`2002/0035974 Al
`
`FOREIGN PATENT DOCUMENTS
`DB-2346266 A * 8/2000
`
`............ H02K/5/08
`
`GB
`
`* cited by examiner
`
`Primary Examiner-Charles G. Freay
`Assistant Examiner-Emmanuel Sayoc
`(74) Attorney, Agent, or Firm-Brooks Kushman P.C.
`
`(57)
`
`ABSTRACT
`
`A fluid pump includes a pump housing having a housing
`cavity with an inlet and an outlet. An encapsulated stator
`assembly is positioned within the housing cavity and at least
`partially defines a fluid passage from the inlet to the outlet.
`A polymeric capsule member encloses and seals the encap(cid:173)
`sulated stator assembly, protecting the motor from, and
`providing heat transfer to, the working fluid. A stator pro(cid:173)
`vides a magnetic field which drives a rotor assembly. The
`rotor assembly rotates an impeller for pumping fluid from
`the inlet to the outlet.
`
`21 Claims, 9 Drawing Sheets
`
`32
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`U.S. Patent
`
`Dec. 9, 2003
`
`Sheet 2 of 9
`
`US 6,659,737 B2
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`U.S. Patent
`
`Dec. 9, 2003
`
`Sheet 3 of 9
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`US 6,659,737 B2
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`14
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`U.S. Patent
`
`Dec. 9, 2003
`
`Sheet 4 of 9
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`U.S. Patent
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`Dec. 9, 2003
`
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`U.S. Patent
`
`Dec. 9, 2003
`
`Sheet 7 of 9
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`Dec. 9, 2003
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`U.S. Patent
`
`Dec. 9, 2003
`
`Sheet 9 of 9
`
`US 6,659,737 B2
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`US 6,659,737 B2
`
`1
`ELECTRONIC FLUID PUMP WITH AN
`ENCAPSULATED STATOR ASSEMBLY
`
`TECHNICAL FIELD
`
`The present invention relates to a fluid pump containing
`an encapsulated stator assembly that seals a pump motor and
`facilitates heat transfer from the motor and the electronics to
`the working fluid.
`
`BACKGROUND ART
`
`2
`In a preferred embodiment, the encapsulated stator assem(cid:173)
`bly is a single unit, and is located inside a two-piece housing.
`A stator comprising steel laminations, windings, and motor
`power leads, is encapsulated in a thermally conductive,
`5 electrically insulative polymeric capsule member. The poly(cid:173)
`meric capsule member defines a rotor cavity having an
`opening. The rotor assembly, consists of a rotor with a rotor
`shaft, the rotor shaft being supported by a front bearing and
`a rear bearing. Also, in the preferred embodiment, the rear
`10 bearing is located within the encapsulated stator assembly,
`and the front bearing and a seal are positioned within a front
`cover that plugs the rotor cavity opening.
`A diffuser is used to help direct fluid flow and thereby
`increase the efficiency of the pump. The diffuser comprises
`an inner wall, an outer wall, and a plurality of diffuser vanes.
`15 The diffuser vanes are integrally molded to the outer wall of
`the encapsulated stator assembly. The polymeric capsule
`member orients the motor power leads with substantial
`circumferential symmetry around the diffuser. The motor
`power leads then interface with a circuit board assembly
`20 near the outlet of the pump. The working fluid flows around
`the outside of the encapsulated stator assembly, thereby
`encountering the diffuser vanes and allowing heat transfer
`from the motor to the fluid. The working fluid then encoun(cid:173)
`ters the encapsulated motor power leads, thereby cooling
`25 both the motor power leads and the circuit board assembly.
`In an alternative embodiment, the one piece encapsulated
`stator assembly is replaced with a one piece stator housing
`assembly. This change allows for larger motors to be utilized
`with the pump, and thereby increases the number of appli-
`30 cations in which the invention may be used. The stator
`housing assembly includes an encapsulated stator assembly
`and a substantially cylindrical metal case which provides an
`outlet for a single bundle of motor power leads and also
`contains diffuser vanes that fully define the boundary of the
`35 working fluid. The encapsulated stator assembly is enclosed
`and sealed by a thermally conductive, electrically insulative
`polymeric capsule member that defines a motor cavity and
`provides a beat transfer path to the working fluid. As in the
`preferred embodiment, a rotor with a rotor shaft is located in
`40 the motor cavity and is driven by the magnetic field gener(cid:173)
`ated by the stator. The motor housing assembly comprises a
`front cover, a stator housing assembly, and a rear cover.
`This alternative embodiment also has a diffuser with
`diffuser walls and diffuser vanes; however, there are now
`two sets of diffuser vanes. The front cover is configured with
`a first set of diffuser vanes and the stator housing assembly
`is configured with a second set of diffuser vanes. The two
`covers and the stator housing assembly are joined together
`and sealed in a manner to prevent the working fluid from
`50 entering the motor cavity.
`Accordingly, an object of the present invention is to
`provide a fluid pump with an encapsulated stator assembly,
`the encapsulated stator assembly orienting the motor com(cid:173)
`ponents and providing beat transfer between the motor and
`55 the working fluid.
`Another object of the invention is to provide a fluid pump
`with an encapsulated stator assembly, the encapsulated sta(cid:173)
`tor assembly forming a diffuser, including a plurality of
`diffuser vanes. The above object and other objects, features,
`60 and advantages of the present invention are readily apparent
`from the following detailed description of the best mode for
`carrying out the invention when taken in connection with the
`accompanying drawings.
`BRIEF DESCRIPTION OF DRAWINGS
`FIG. 1 shows a longitudinal cross-sectional view of a fluid
`pump in accordance with the present invention;
`
`Use of fluid pumps in vehicle engine cooling systems and
`various industrial applications is well known. However,
`typical fluid pumps in both of these areas have inherent
`limitations.
`Typically in engine cooling systems, a coolant pump has
`a pulley keyed to a shaft. The shaft is driven by the engine
`via a belt and pulley coupling, and rotates an impeller to
`pump the working fluid. Fluid seals sometimes fail due to
`the side load from the drive belt, which tends to allow fluid
`to leak past the seal into the bearing.
`U.S. Pat. No. 6,056,518, issued on May 2, 2000 to Allen
`et al., describes one attempt to overcome the shortcomings
`of prior art vehicle coolant pumps. The '518 patent provides
`a fluid pump with a switched reluctance motor that is
`secured to a housing and rotates an impeller for pumping the
`fluid. This design eliminates the side load problem associ(cid:173)
`ated with keyed pulleys, but it is generally not intended for
`use where larger industrial pumps are required.
`Industrial pumps are typically driven by an electric motor
`connected to the pump via a coupling, the alignment of
`which is critical. Misalignment of the coupling can result in
`premature pump failure, which leads to the use of expensive
`constant velocity couplings to overcome this problem.
`Moreover, industrial pumps are typically air-cooled, relying
`on air from the surrounding environment. The cooling air is
`drawn through the motor leaving airborne dust and other
`contaminants deposited in the motor. These deposits can
`contaminate the bearings, causing them to fail, or the
`deposits can coat the windings, shielding them from the
`cooling air and causing the windings to overheat and short
`out.
`Accordingly, it is desirable to provide an improved fluid 45
`pump which overcomes the above-referenced shortcomings
`of prior art fluid pumps, while also providing enhanced fluid
`flow rate and control capability while reducing costs.
`
`DISCLOSURE OF INVENTION
`The present invention provides a fluid pump with an
`encapsulated stator assembly that contains a rotor cavity. A
`rotor assembly, driven by a stator, is positioned within this
`cavity and turns an impeller for pumping the working fluid.
`The encapsulated stator assembly prevents the working fluid
`from directly contacting the motor. It does, however, have an
`outside wall that is in contact with the working fluid, thereby
`facilitating heat transfer from the motor to the fluid.
`More specifically, the present invention provides a fluid
`pump including a housing having a housing cavity therein.
`An encapsulated stator assembly is positioned within the
`housing cavity and at least partially defines a boundary for
`the working fluid. The encapsulated stator assembly con(cid:173)
`tains a rotor cavity in which a rotor assembly is located. The
`magnetic field generated by a stator drives the rotor 65
`assembly, which is connected to an impeller for pumping the
`fluid.
`
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`

`

`US 6,659,737 B2
`
`3
`FIG. 2 shows a longitudinal cross-sectional view of an
`encapsulated stator assembly for use with the pump shown
`in FIG. 1;
`FIG. 3 shows a perspective view of the encapsulated
`stator assembly, with the motor cavity opening toward the
`front and the motor power leads toward the back;
`FIG. 4 shows a rear perspective view of an impeller for
`use with the pump shown in FIG. 1;
`FIG. 5 shows a perspective view of a two piece pump
`housing with an inlet housing toward the front and an outlet
`housing toward the rear for use with the pump shown in FIG.
`1;
`
`4
`metry around the longitudinal axis of the encapsulated stator
`assembly 22. As seen in FIG. 1, motor power leads 32
`interface with a circuit board assembly 34.
`Returning to FIG. 1 impeller 16 is slip fit onto the rotor
`5 shaft 28b and secured with a buttonhead capscrew 50. A
`drive pin 30 transversely located through rotor shaft 28b
`drives impeller 16 via slot 23.
`FIG. 4 shows impeller 16 with slot 23 configured to
`receive drive pin 30. FIG. 5 shows the inlet pump housing
`10 12 attached to the outlet pump housing 14. Outlet pump
`housing 14 is again shown in FIG. 6, this time with motor
`power leads 32. FIG. 7 shows the outside of pump 10
`including the inlet pump housing 12, the outlet pump
`housing 14, the circuit board assembly 34, and the connec-
`15 tion points between circuit board assembly 34 and the motor
`power leads 32.
`Referring to FIG. 8, a fluid pump 60 is shown in accor-
`dance with one alternative embodiment of the invention.
`Although similar in function to the preferred embodiment,
`there are a number of notable differences with regard to
`form. Rather than a two-piece housing, this embodiment
`employs a three-piece housing comprising an inlet housing
`62, a stator housing assembly 64, and an outlet housing 66,
`assembled with bolts 68.
`The stator housing assembly 64, shown in FIG. 10 and
`sectioned in FIG. 11, includes an encapsulated stator assem(cid:173)
`bly 75 and a substantially cylindrical metal case 73 which
`provides an outlet for a single bundle of motor power leads
`92 and diffuser vanes 83 that fully define the boundary of the
`working fluid. The encapsulated stator assembly 75 includes
`a plurality of steel laminations 90a, a plurality of windings
`90b, and a plurality of motor power leads 92. A polymeric
`capsule member 77 encloses and seals the stator assembly
`35 90, and also defines a rotor cavity 79.
`As shown in FIG. 9, a rotor assembly 82, consisting of a
`rotor 82a and a rotor shaft 82b, mislocated within rotor
`cavity 79. Rotor shaft 82b is supported by a rear bearing 96
`positioned within the rear cover 74 which plugs the rear
`40 opening of the rotor cavity 79, and a front bearing 86 and
`seals 100 positioned within a front cover 70 which plugs the
`forward opening of the rotor cavity 79. Drive pin 84 is
`positioned transversely through rotor shaft 82b and drives
`impeller 76.
`Referring to FIG. 9, unlike the preferred embodiment, this
`alternative embodiment has two separate sets of diffuser
`vanes, the first set 81 being configured on the front cover 70
`and the second set 83 being configured on the stator housing
`assembly 64.
`FIGS. 10 and 11 clearly show the resultant fluid passage
`88 formed between the vanes 83 and the inner and outer
`walls 73a, 73b of the metal case 73.
`The encapsulated stator assembly 75 may be manufac(cid:173)
`tured by locating the stator assembly 90 within the substan-
`55 tially cylindrical metal case 73 and temporarily capping the
`two open ends of the metal case. The stator assembly 90
`would then be encapsulated in a polymeric thermally
`conductive, electrically insulative material 77. The opposing
`ends of the metal case would be uncapped, and the front and
`60 rear covers 70, 74 would be attached to the metal case to
`complete the encapsulated stator assembly 75.
`FIG. 12 shows a second alternative embodiment of the
`fluid pump of FIG. 1. Seal cartridge assembly 26 plugs
`opening 19 in rotor cavity 17. Wear sleeve 24 is slip fit over
`65 the end of rotor shaft 52b. An impeller 16 is slip fit onto wear
`sleeve 24 and is secured to rotor shaft 52b with a buttonhead
`capscrew 50. A drive pin 30 transversely located through
`
`FIG. 6 shows a perspective view of the outlet housing
`corresponding with the embodiment of FIG. 1;
`FIG. 7 shows a perspective view of the outlet housing of
`FIG. 6, with a circuit board assembly attached;
`FIG. 8 shows a side view of a fluid pump in accordance
`with an alternative embodiment of the invention;
`FIG. 9 shows a longitudinal cross-sectional view of the 20
`fluid pump shown in FIG. 8;
`FIG. 10 shows a perspective view of the stator housing
`assembly of the fluid pump of FIG. 8;
`FIG. 11 shows a longitudinal cross-sectional view of the 25
`stator housing assembly of FIG. 10;
`FIG. 12 shows a longitudinal cross-sectional view of a
`second alternative embodiment of the fluid pump of FIG. 1;
`FIG. 13 shows a longitudinal cross-sectional view of a
`seal cartridge assembly for use with the pump shown in FIG. 30
`12;
`FIG. 14 shows a perspective view of the seal cartridge
`assembly and one end of the rotor shaft with a drive pin for
`use with the pump shown in FIG. 12.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`FIG. 1 shows a longitudinal cross-sectional view of a fluid
`pump 10 in accordance with the present invention. A two(cid:173)
`piece pump housing comprises an inlet pump housing 12
`and an outlet pump housing 14. The pump housing has a
`housing cavity 15 therein which contains an encapsulated
`stator assembly 22.
`Referring to FIG. 2, the encapsulated stator assembly 22 45
`defines a rotor cavity 17 with an opening 19. The encapsu(cid:173)
`lated stator assembly 22 comprises a polymeric capsule
`member 21, that has a plurality of diffuser vanes 18 molded
`integrally thereon. Polymeric capsule member 21 encloses
`and seals a motor stator 20 and motor power leads 32. Thus, 50
`when the fluid pump 10 is used in an engine cooling system,
`the motor stator 20 and motor power leads 32 are protected
`from the liquid engine coolant. Motor stator 20 comprises a
`plurality of steel laminations 20a and a plurality of copper
`windings 20b.
`Returning to FIG. 1, located within rotor cavity 17 is a
`rotor assembly 28, consisting of a rotor 28a and a rotor shaft
`28b. The rotor shaft 28b is supported by a front bearing 42
`and a rear bearing 40. Rear bearing 40 is located within the
`encapsulated stator assembly 22. Front bearing 42 and seal
`44 are located within the front cover 26 that plugs the rotor
`cavity opening 19.
`FIG. 3 shows a front perspective view of encapsulated
`motor assembly 22. In particular, it shows diffuser vanes 18
`which are of split construction (but need not be of split
`construction for this invention), and the motor power leads
`32 which are oriented with substantial circumferential sym-
`
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`US 6,659,737 B2
`
`5
`
`35
`
`5
`rotor shaft 52b and wear sleeve 24 serves multiple functions.
`The drive pin 30 drives impeller 16 via slot 23 (similarly as
`shown in FIG. 4); it prevents wear sleeve 24 from rotating
`relative to rotor shaft 52b; it captures axial loads from rotor
`assembly 52.
`Some of the features and components of the seal cartridge
`assembly 26 are shown in FIGS. 12 and 13. Body 27 has a
`wet side 31 in contact with the working fluid, such as a liquid
`engine coolant, and a dry side 29. The body 27 also contains
`a plurality of holes 47 for attaching the seal cartridge 10
`assembly 26 to the encapsulated stator assembly 57, using
`bolts 48. A seal 53 is press fit into the body 27 and plugs an
`opening on the wet side 31.
`Referring to FIG. 14, the wear sleeve 24 is machined to
`form an inner diameter and has an axis coaxial to an axis of
`the body 27. A hole 25 is machined transverse to the wear 15
`sleeve axis and is configured to receive drive pin 30. The
`rotor shaft 52b has a transverse hole 56 that also receives
`drive pin 30.
`Returning to FIG. 13, the front bearing 51, being press fit
`onto the substantially cylindrical wear sleeve 24, plugs an 20
`opening on the dry side 29. The bearing 51 and wear sleeve
`24 are press-fit into the cartridge body, and the wear sleeve
`24 is slip fit over the shaft 52b. The seal cartridge assembly
`26 also contains leak detection ports 33, shown in FIG. 14,
`for visual or electronic indication of seal 53 failure.
`While embodiments of the invention have been illustrated
`and described, it is not intended that these embodiments
`illustrate and describe all possible forms of the invention.
`Rather, the words used in the specification are words of 30
`description rather than limitation, and it is understood that
`various changes may be made without departing from the
`spirit and scope of the invention.
`What is claimed is:
`1. A fluid pump, comprising:
`a housing having a housing cavity therein with an inlet
`and an outlet;
`an impeller rotatably positioned at the inlet and having an
`impeller axis;
`an encapsulated stator assembly enclosed and sealed by a 40
`polymeric capsule member, the polymeric capsule
`member defining a rotor cavity having an opening, and
`orienting motor power leads with substantial circum(cid:173)
`ferential symmetry around the impeller axis, the encap(cid:173)
`sulated stator assembly including a plurality of steel 45
`laminations, a plurality of copper windings, and a
`plurality of motor power leads;
`a rotor assembly rotatably located inside the rotor cavity
`and connected to the impeller for rotating the impeller
`for pumping fluid through the passage from the inlet to 50
`the outlet; and
`a seal cartridge assembly positioned within the opening
`for sealing the rotor assembly within the rotor cavity.
`2. The fluid pump of claim 1, wherein the polymeric
`capsule member comprises a thermally conductive, electri- 55
`cally insulative material.
`3. The fluid pump of claim 1, further comprising a circuit
`board assembly located near the outlet and interfacing with
`the motor power leads.
`4. The fluid pump of claim 1, further comprising a 60
`diffuser, wherein the diffuser comprises an inner wall formed
`by an outer wall of the encapsulated stator assembly, an
`outer wall formed by an inner wall of the housing, and a
`plurality of diffuser vanes.
`5. The fluid pump of claim 4, wherein the outer wall of the 65
`encapsulated stator assembly is configured with the diffuser
`vanes.
`
`6
`6. The fluid pump of claim 1, wherein the rotor assembly
`consists of a rotor with a rotor shaft.
`7. The fluid pump of claim 6, wherein the rotor shaft is
`supported by a front bearing and a rear bearing.
`8. A fluid pump, comprising:
`a housing having a housing cavity therein with an inlet
`and an outlet;
`an encapsulated stator assembly enclosed and sealed by a
`polymeric capsule member, the polymeric capsule
`member being separate from the housing and enclosing
`the stator assembly in such a way as to provide sub-
`stantial contact with outer peripheral surfaces of the
`stator assembly, thereby minimizing voids therebe(cid:173)
`tween and facilitating conductive heat transfer between
`the stator assembly and the capsule member, wherein
`the polymeric capsule member defines a rotor cavity
`having an opening; and
`wherein an outer wall of the polymeric capsule member
`has a plurality of diffuser vanes molded integrally
`thereon, the diffuser vanes being separate from the
`housing.
`9. The fluid pump of claim 8, wherein the polymeric
`capsule member comprises a thermally conductive, electri(cid:173)
`cally insulative material.
`10. The fluid pump of claim 8, wherein the encapsulated
`25 stator assembly comprises a plurality of steel laminations, a
`plurality of copper windings, and a plurality of motor power
`leads.
`11. The fluid pump of claim 10, wherein the polymeric
`capsule member orients the motor power leads with sub(cid:173)
`stantial circumferential symmetry around the impeller axis.
`12. The fluid pump of claim 10, further comprising a
`circuit board assembly located near the outlet and interfac(cid:173)
`ing with the motor power leads.
`13. A fluid pump, comprising:
`a housing having a housing cavity therein with an inlet
`and an outlet;
`an encapsulated stator assembly enclosed and sealed by a
`polymeric capsule member;
`wherein the encapsulated stator assembly contains a plu(cid:173)
`rality of motor power leads encased in the polymeric
`capsule member, and having exposed ends, the motor
`power leads being at least partially within the fluid flow
`path; and
`a circuit board assembly positioned near the outlet and
`interfacing with the ends of the motor power leads.
`14. The fluid pump of claim 13, wherein the polymeric
`capsule member comprises a thermally conductive, electri(cid:173)
`cally insulative material.
`15. The fluid pump of claim 13, wherein the polymeric
`capsule member orients the motor power leads with sub(cid:173)
`stantial circumferential symmetry around the impeller axis.
`16. The fluid pump of claim 13, further comprising a
`diffuser, wherein the diffuser comprises an inner wall formed
`by the outer wall of the encapsulated stator assembly, an
`outer wall formed by the inner wall of the housing, and a
`plurality of diffuser vanes.
`17. The fluid pump of claim 16, wherein the outer wall of
`the encapsulated stator assembly is configured with the
`diffuser vanes.
`18. A fluid pump, comprising:
`a housing having a housing cavity therein with an inlet
`and an outlet;
`an impeller rotatably positioned at the inlet and having an
`impeller axis;
`an encapsulated stator assembly enclosed and sealed by a
`polymeric capsule member, the polymeric capsule
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`US 6,659,737 B2
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`7
`member defining a rotor cavity having an opening, and
`orienting motor power leads with substantial circum(cid:173)
`ferential symmetry around the impeller axis, the encap(cid:173)
`sulated stator assembly including a plurality of steel
`laminations, a plurality of copper windings, and a 5
`plurality of motor power leads; and
`wherein the polymeric capsule member comprises a ther(cid:173)
`mally conductive, electrically insulative material.
`19. The fluid pump of claim 18, further comprising a
`circuit board assembly located near the outlet and interfac(cid:173)
`ing with the motor power leads.
`
`8
`20. The fluid pump of claim 18, further comprising a
`diffuser, wherein the diffuser comprises an inner wall formed
`by an outer wall of the encapsulated stator assembly, an
`outer wall formed by an inner wall of the housing, and a
`plurality of diffuser vanes.
`21. The fluid pump in claim 20, wherein the outer wall of
`the encapsulated stator assembly is configured with the
`diffuser vanes.
`
`* * * * *
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` 11/15/2018, EAST Version: 4.1.2.6
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