US2939400A

US2939400A - Submersible motor-pump assembly

Info

Publication number: US2939400A
Application number: US583046A
Authority: US
Inventors: John T Maynard
Original assignee: AO Smith Corp
Current assignee: AO Smith Corp
Priority date: 1956-05-07
Filing date: 1956-05-07
Publication date: 1960-06-07
Anticipated expiration: 1977-06-07

Description

June 7, 1960 J. T. MAYNARD SUBMERSIBLE MOTOR-PUMP ASSEMBLY \i'iiinml N ENTOR,

H'Orneqs BYWMQLM I n l w 4 I n Mm rllllllllr m United States Patent SUBMERSIBLE MOTOR-PUMP ASSEMBLY John T. Maynard, West Allis, Wis., assignor to 0. Smith Corporation, Milwaukee, Wis, acorporatlon of New York Filed May'7, 1956, Ser. No. 583,046

1 Claim. (Cl.'103-87) This invention relates to a submersible motor-pump assembly and in particular. to.amotor-pump assembly having a-rnulti-stage pump.

The general construction of a submersible' motorpump assembly comprises a separatemotorand. pump unit having the respective shafts coupled together and adapted to be lowered into a well with the motor and the pump' submersed into the well liquid. A spacer structure secures the pump and the motor in spaced relation toallow the water to enter the lower end.of the pump which forces the water upwardly through a stringer pipe leading to the top of the well. vided with a thrust hearing at its lower end to take up the thrust forces during operation. The motor and pump ice which is shown in thedrawing. At its upper end-the rotor is supported by-a radial bearingltl, more. fully) described hereinafter. The power lines 11 which are connected to a field winding 12 within the stator extend from the stator assembly 1 through an opening in the,

upper stator end member 13. The opening is sealed by potting with any suitable resin 14 to prevent fluid leakage;

into the stator assembly. The shaft 9 of motor, 1 extendsupwardly through a portion of the spacing: member 3, and is splinedon its exterior periphery as at 15 to mate with an internally splined recess in an enlarged end por.-;

tion 16 .of the pump shaft 17.'

The splined coupling rotatably. binds and axially alignsv the motor shaft 9 andthepump shaft 17:. As the upper motor radialbearing is to radially supportthe lower end of the pump shaft, a coupling or. other relatively rigid,-

' through adischarge nozzle 21 which is connected to a are each-provided with their own upper and lower radial bearing to radially support and 1 align'lthe respective shafts. a

In accordance with the present invention; the spacer member is preferably integrally cast [with the upper motor bearing housing and the base for thepump as sembly. Whenintegrally cast, the'conventionalpump suction castingis eliminated with the up'per motor housing serving the dual purpose of a bearing support and .alsosupporting the pump. The construction of the present invention eliminates the'lower pump hearing. The cast spacer is smaller than the conventionalspacer structure and the upper radial bearing of the motor also radially supports the lower end of the'pump shaft and consequently serves'as the lower pump hearing.

The present invention providesasimplified, compact motor-pump assembly with reduced. cost of material and assembly.

The drawing furnished herewith illustrates..-the-. best mode presently contemplated forcarrying out. thelinvem tion. I V

In the drawing:

Figure 1 is an elevational view of a submersible motorpump-unit embodying the invention with parts broken away and sectioned; 1

Fig. 2 is a view taken on the line 22 of Figure 1;

Figure 3 is a fragmentary elevational view with a portion broken away and sectioned of a spacer member shown in Figure l; and

Figure 4 is a perspective view of an integrally formed bearing housing-spacer-pump base member.

Referring to the drawing and particularly Figure 1, a submersible motor 1 is coupled in driving relation to the lower end of a multi-stage pump 2 and is connected in spaced relation thereto by a spacing member 3. The unit is lowered into a well 4 from which water 5 is to be pumped with the motor 1 and at least the lower endiof' stringer tube .22. Aconventional coupling 23 threads.

- onto the outer. end. of the discharge nozzle 21 and the The motor ispro stringer. .tubea22 .toconnect them together. A floatvalve 24 in the coupling 23 prevents the Water once pumped into the tube 22.from returningrto the well.

' Each. stage of the pump 2 comprises a housing. 25 within; which. an impeller. 26 rotates .and centrifugally forces .thewater to the succeeding. stage. Eachimpeller 26isalockedto..the,,pump shaft 17 by a key 27. The

ing an annular stator assembly 7 with a rotor 8 rotatably mounted within the bore of the stator. The rotor is secured to a motor shaft 9 and is supported at the lower end by a thrust bearing and a radial bearing, neither of housings 25 are stacked one upon' another with theafirst stage resting on theisbase 19. The lower periphery of each housing 25: is recessed-to accommodateanupstande ing flange portion "28 of theimmediately lower housing except for the first stage;which.. receives. an upstanding flangeaportion 29 of the base19. The plurality of .pump stages are secured in..stacked"relation by a sleeve casing 30. whichis crimped at each end upon projections 31and 32rformed-respectively on the lower surface of the base portion 19 and the discharge nozzle 21 of the .pump' 2. Thespacing member 3, aperspective view being shown in Fig. 4, comprises an upper motor bearing housing 33 and theg pump base 19 .which .ar'etconnected by a plurality of spacer struts 34 formedintegrally at their ends with the housing and base. The spacing member 3is preferably made as ,.a. single casting to obtain maximum economy in. construction and-assembly.

The upper bearing housing 33 is a generally thick,

circular member with a downwardly depending hub 35 having a central bore through which the motor shaft 9 extends. The radial bearing 10, previously described, is secured within the hub 35.

The spacing member 3 is secured to the stator end plate 13, with the hub 35 extending into the rotor cham- 'ber 36, by a plurality of bolts 37 which pass through suitable openings in the housing 33 and thread into suitably tapped openings in the end plate. A lead-in plug 38 extends through the circular member of housing 33 for passage of the power lines 11.

The radial bearing 10 secured within the bore of the hub 35 maintains the radial alignment of motor shaft 9 and pump shaft 17. A shaft seal 39 is disposed within a recess in the housing through which shaft 9 passes to restrict entry of water and foreign matter into the rotor chamber 36 and a seal cover 40 overlies seal 39 to frictionally hold it in place. A sand slinger '41 is secured.

tothe shaft immediately adjacent the shaft seal 39 to centrifugally throw larger foreign particles from about the seal.

A radial bearing 42 is provided at the upper end of the pump shaft 17 and a radial bearing, not shown, is provided at the lower end of the motor shaft 9 to complete the radial support for the shafts 17 and 9.

The motor 1 is adapted to. run with the rotor chamber 36 filled with water. As more clearly illusrtated in Figs. 2 and 3, to initially fill the rotor chamber with Water, a water inlet is formedby a tapped opening 43 extending laterally inwardly'within an enlarged portion 44 on the top of the circular member of housing 33 and into communication with a longitudinal opening 45 in the housing adjacent the hub 35. The opening 45 is in communication with the rotor chamber 36 which may be filled with water and a plug 46 then threaded into the lateral opening 43 to seal the passage.

A similar passage is also formed in circumferential spaced relation to the first passage by a lateral opening 47 formed in an enlargedportion 48 and longitudinal opening 49 in the housing .33. The latter passage allows the air in the rotor chamber 36 to escape while filling with water. The lateral opening 47 is also tapped to receive a correspondingly threaded plug 50 which seals the passage after the rotor chamber 36 is filled. This prevents formation of air pockets and allows rapid filling of the rotor chamber.

The four circumferentially spaced struts 34 are integrally formed with the housing. portion of the spacing member 3 and hold the integrally formed pump base 19 in vertically spaced relation to the motor 1 to thereby allow entry of water to the inlet 18 of the pump 2. Each strut 34 extends radially from the structure of seal 40 to 18 disposed below the upper level of the water; The unit is started and stopped by remotely controlling the energization of the stator winding 12 via the power lines 11.

When energized, the motor 1 drives the pump 2 which draws water in through the lower end of the pump and raises it through the various pump stages, discharging it through the discharge nozzle into the stringer tubing which carries the water from the well.

The combined bearing-spacer 3 permits the entryof water into the lower end of the pump assembly. .As previously noted, the spacing struts are shortened to a minimum consistent with a satisfactory water flow.

the outer edge of the housing. The inner vertical surface751 of each strut 34 is generally vertical .with the outer vertical surface 52 tapering inwardly and upwardly to the base portion 19 with the circumferential lip 31,

about which the pump casing 30 is crimped, encircling the upper ends of the struts.

-.The length of the struts 34 is maintained at a minimum consistent with allowance for suitable flow to the pump opening 18 and coupling of the motor shaft, 9 and the pump shaft 17. In this manner, the pump shaft 17 is maintained and radially supported in alignment without the necessity of a lower radial bearing for the pump.

j; The base portion 19 is generally ring-shaped and has the lip 31 and flange 29 integrally formed with the struts 34. i T I i A screen 53 encircles the struts 34'and the'circular portion of housing 33 and tapers inwardly as at 54 to dispose the top edge within the depending base lip 31. Set screws 55 thread into housing 33 and secure the screen in position. I I p In operation, the submersible motor-pump unit is lowered into the well 4 with the motor 1 and water inlet The present invention eliminates the radial bearing for the lower end of the pump. and permits a substantial reduction in the size ofthe spacing structure. By forming the bearing housing, strut spacers and pump base as an intgeral cast unit substantial economy of materials and assembly is obtained.

Various modes of carrying out the invention are contemplated as being within the scope of the following claim particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim: 1 r

A submersible motor pump assembly comprising an electric motor, a spacing member mounted on said motor and having a plurality of openings therein for passage of fluid to be pumped and a hub integral therewith and extending within said motor, a shaft disposed Within the motor and driven thereby and extending within said hub, a pump unit mounted on the spacer member and having a plurality of vertically stacked impellers located-therein and a shaft extending through the impellers to which the impellers are secured and depending into said spacer member into engagement with the motor shaft to be driven by said motor shaft, a bearing confined within said hub in engagement with the motor shaft to support the motor shaft and pump shaft against radial thrust and thereby eliminate a separate bearing support for the lower end of the pump shaft, and a shaft sealing means disposed around the motor shaft within the spacing member and at the end of the bearing exposed to the fluid being pumped to restrict entry of fluid and foreign matter to the bearing and motor.

References Cited in the file of this patent, UNITED STATES PATENTS 2,043,236 Conant June 9, 1936 2,366,964 Howard Jan. 9, 1945 2,648,286 Bergh Aug. 11, 19.53 2,667,128 Bergh Jan. 26, 1954 2,787,960 Wightma'n' Apr. 9, 1957 Rice .Dec. 17, 1957