US3437045A - Submersible pump - Google Patents

Description

April 8, 1969 D. TREMAIN SUBMERSIBLE PUMP Filed Aug. 31, 1967 INVENTOR DAVID L. TREMAIN FIG'I ATTORNEYS United States Patent 3,437,045 SUBMERSIBLE PUMP David L. Tremain, Dayton, Ohio, assignor to The Tait Manufacturing Company, Dayton, Ohio, a corporation of Ohio Filed Aug. 31, 1967, Ser. No. 664,657 Int. Cl. F0411 13/02; F0d 1/06 US. 'Cl. 103-87 11 Claims ABSTRACT OF THE DISCLOSURE Background of the invention In a submersible multistage centrifugal pump and motor assembly such as disclosed in Patent No. 3,070,026, issued to the assignee of the present invention, and which is adapted to be lowered into a well casing so that the entire assembly is submerged substantially below the water level, the overall diameter of the assembly is determined by the inside diameter of the well casing. That is, the outside diameter of the pump assembly must be sufficiently smaller than the inside diameter of the casing to provide clearance for conveniently inserting the pump into the casing. In an assembly of predetermined overall diameter, however, it is highly desirable to use impellers with a diameter as large as possible to obtain maximum pressure increase within each stage of the pump.

As disclosed in the above patent, the multi-stage pump includes a plurality of cup-like pump cases each of which encloses a plastic molded impeller having a bottom inlet. A plastic molded diffuser is attached to each case and has diffusing vanes for directing the discharged flow of water from one impeller to the inlet of the next impeller thereabove while converting the velocity head into pres sure head. The cases are retained in their stacked relation by a series of axially extending tie bolts which sandwich the cases between the lower intake housing mounted on the motor and the upper discharge housing connected to the lower end of a discharge pipe.

It is desirable to protect the motor leads extending downwardly along the outer surface of the pump from rubbing against the inner surface of the well casing. As shown in the above patent, the leads are commonly protected by an elongated shield which is attached to the outer surface of the pump. Another way of protecting the leads is to confine all of them within an axially extending slot formed within the pump cases and surround the cases with a cylindrical metal shell as disclosed in Patent No. 2,667,128, also assigned to the assignee of the present invention.

Summary of the invention The present invention is directed to an improved submersible pump of the type outlined above, and which particularly provides for using maximum diameter impellers within a pump assembly of predetermined overall diameter for obtaining optimum pump performance, and which also provides for protecting the power supply Patented Apr. 8, 1969 leads extending to the motor. In accordance with a preferred embodiment of the invention, each pump case is constructed of a suitably rigid plastic and includes a radial wall having a central inlet opening and a generally cylindrical outer wall of substantially uniform thickness. The outer wall has a series of uniformly spaced axially extending depressions which define external grooves or slots each of sufficient size to receive a single motor lead. Thus on a pump assembly wherein the motor has an internal starting switch, only two of the slots are used for motor leads, whereas in a unit having a remote relay-type starting switch, three or four of the slots may be used. Thus the motor leads are separately inserted within the slots and are protected along with the plastic pump cases by a cylindrical metal shell surrounding the cases.

A diffuser is positioned within each case and includes a series of peripherally spaced overlapping vanes which project axially from a radial wall to form a volute-shaped radially diffusing passageway between each pair of adjacent depressions or slots within the corresponding case. These passageways are connected to corresponding generally radially extending diffusing passageways defined between the radial wall of each case and the adjacent radial wall of the corresponding diffuser.

With each case and diffuser constructed in accordance with the invention, significantly larger diameter cases and impellers can be used within a pump of predetermined overall diameter so that maximum pressure increase can be obtained within each stage of the pump. Furthermore, the motor leads extending along the side of the pump are protected without any sacrifice in impeller diameter.

Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

Brief description of the drawings FIG. 1 is an elevational view of a submersible pump constructed in accordance with the invention;

FIG. 2 is an enlarged fragmentary view of the pump in axial section generally on the line 22 of FIG. 3;

FIG. 3 is a radial section taken generally on the line 3-3 of FIG. 2;

FIG. 4 is a top view of one of the cases in the pump of FIGS. 1-3 with a portion broken away to show the top side of the diffuser mounted therein; and

FIG. 5 is a fragmentary bottom View of one of the diffusers in the pump of FIGS. 1-3.

Description of preferred embodiments The submersible pump assembly shown in FIG. 1 generally includes a pump 10 of the multistage centrifugal type, a motor 12, motor leads 14, and an intake housing 15 (FIG. 2) which serves to connect the pump 10 rigidly to the motor 12. A cylindrical screen '16 surrounds the intake housing 15 and serves to filter the water flowing into the pump 10.

The motor -12 includes a cylindrical casing 20' connected to an upper bearing bracket 21 from which a shaft 22 projects upwardly into the intake housing '15. The housing 15 includes a lower base portion 2'5 having a series of holes for receiving corresponding studs '26 projecting upwardly from the bearing bracket 21. Nuts 27 and lock washers 28 secure the intake housing 15 rigidly to the bearing bracket 21.

The intake housing 15 includes an upper flange portion 30 which is integrally connected to the base portion 25 by a series of axially extending ribs 31, and the pump 10 includes an outer cylindrical shell 35 having its lower end seated on an external peripheral shoulder '36 formed on the flange portion 30. The pump shell 35 is rigidly secured to the intake housing 15 by a series of screws 37 which project through axially extending holes formed Within a shell 35 firmly against the shoulder 36 of the intake housing.

Referring to FIGS. 2 and 3, a plurality of cup-shaped pump cases 45 are arranged in stacked relation within the pump shell '35 with the lower case seated on the upper flange portion 30 of the intake housing 15. Each case 45 is molded from a rigid plastic material and includes a radial wall 46 (FIGS. 2 and 4) having a central opening defined by a cylindrical lip 48 of a sheet metal ring inserted into the mold prior to molding the case.

The generally cylindrical outer wall 50 of each case 45 is of uniform thickness and provided with a series of uniformly spaced axially extending depressions or shaped portions 51 each defining a corresponding U- shaped slot 62. As shown in FIG. 3, each slot 52 has a depth approximately equal to the diameter of a motor lead 14. Referring to FIG. 2, two motor leads 14 extend upwardly from the motor 12 within two of the slots 52 and are retained therein by the pump shell B S. As mentioned above, when additional leads are required for the motor 20, additional slots 52 are used so that only one lead is confined within each slot.

A peripheral step or shoulder 55 (FIG. 2) is formed within the upper end portion of each case 45, and the shoulder extends around each of the U-shaped portions 51 so that the cases 45 nest together in a positive interfitting aligned relation and are thereby prevented from rotating relative to each other. As mentioned above, the slots '52 are uniformly spaced within the outer wall 50 of each case 45, and thus the cases can be stacked without any particular orientation except for the aligning of the slots 52.

A diffuser 60 molded of rigid plastic is mounted within each of the pump cases 45 and includes a radial wall 62 which is spaced from the radial case wall 46 by a series of V-shaped ribs 63 cooperating with the radial walls 46 and 62 to define a plurality of generally radially extending uniformly arranged passageways 65 FIG. 4). The passageways 65 increase in cross-sectional area towards the center to provide further diffusion of velocity head into pressure head. A central opening 66 (FIG. 4) is formed within the radial wall 62 of each diffuser 60 by the cylindrical lip 67 of a sheet metal ring inserted within the mold prior to molding the diffuser. The lip 67 is concentric with the lip 48 and is smaller in diameter to define an annular passageway 70.

Referring to FIGS. 3 and '5, a series of uniformly spaced peripheral vanes 75 project downwardly from the radial wall 62 of each diffuser 60. Each vane includes an outer portion 76 (FIG. 3) which is positioned between an adjacent pair of U-shaped portions 51 of the case outer wall 50 and a thinner integral lip portion 77 which is spaced radially inwardly from the portion 76 of the adjacent vane 75 to form a volute-shaped radial diffusing passageway 80 therebetween. Each vane 75 also includes an axially extendingpart-cylindrical surface 81"(FIG. which receives the adjacent U-shaped portion 51 of the outer wall 50 and thereby prevents relative rotation of each diffuser 60 within its corresponding case 45.

As shown in FIG. 5, there is a space 82 located between e'ach adjacent pair of vanes 75 and adjacent the outer ends of each passageway 65 so that when each diffuser 60 is assembled into its corresponding case 45, each space 82 forms an axially extending passageway or port 84 ('FIG. 3) adjacent each of the U-shaped portions 51 of the diffuser outer wall "50. The passageways 84 interconnect the outwardly diffusing passageways 80 with the corresponding inwardly diffusing passageways 65.

A centrifugal impeller 85 is positioned within each of the pump cases 45 and has a cylindrical hub portion '86 which extends through the central opening 66 of the cor-' 7 4 responding diffuser in close fitting relation to the cylindrical lip 67. All of the impellers are mounted on a splined pump shaft 88 with the hub portions -86 in stacked relation, and the lower end of the pump shaft 88 is connected to the motor shaft 22 by a suitable coupling 90. The upper end portion of the pump shaft 86 is rotatably supported by a bearing (not shown) supported within a discharge housing 92 secured to the upper end portion of the pump shell 35.

As shown in FIG. 2, each impeller 85 includes a radial wall 95 projecting from its hub portion '86 and an annular radial wall 96 spaced from the wall 95 by a series of curved vanes 98. A cylindrical wall 99 projects downwardly from the radial wall 96 of each impeller 85 into the opening defined by the cylindrical lip 48 projecting upwardly from the adjacent radial wall 46 of the corresponding case 45. The wall 99 of each impeller co operates with the hub portion 86 to define an annular inlet 100.

In operation, the water flows through the cylindrical screen 16 surrounding the intake housing 15 and enters the inlet 100 of'the lowermost impeller 85. The Water is discharged from this impeller into the volute-shaped diffusing passageways 80 and then flows axially through the ports 84 and radially inwardly through the diffusing passageways 65 to the inlet 100 of the next above impeller 85. The water repeats this flow path through each successive stage of the pump causing a progressive increase in presure until it is discharged through the discharge housing 92.

From the drawings and the above description, it can be seen that a multi-stage submersible pump constructed in accordance with the invention provides several desirable features and advantages. For example, by forming the uniformly spaced small slots 52 within the pump cases 45 and separating the motor leads 14 with a single motor lead in each slot, the motor leads are encased by the cylindrical pump shell 35 and are thereby protected from being damaged when lowering the pump assembly into a well casing.

Furthermore, with the overlapping diffuser vanes so arranged that the radially diffusing passageways and corresponding ports 84 are positioned between the U- shaped outer wall portions 51 defining the slots 52, the high velocity discharge of water from each impeller is diffused to a lower velocity, higher pressure flow between the slots 52. Thus the water discharged from each impeller is diffused and directed to the next adjacent stage in an annular area which is usually occupied by only the motor leads. As a result, the case and diffuser construction of the invention provide for using maximum diameter impellers so that maximum pressure increase can be obtained within each stage of the pump.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. In a submersible water pump assembly adapted to be lowered into a well casing and including an electric motor having a shaft projecting from one end, a multistage pump secured to said end of said motor and including a series of pump cases arranged in aligned stacked relation, each said case including a generally cylindrical outer wall, a centrifugal impeller positioned within each said case, and means connecting said impellers to said motor shaft, the improvement comprising means defining a plurality of generally axially extending peripherally spaced slots within said outer walls of said cases, diffuser means defining a corresponding plurality of diffusing pasageways located between said adjacent pair of said slots, and a plurality of power supply leads extending to said motor through a plurality of said slots to provide for using maximum diameter said cases and impellers within said well casings for obtaining optimum pressure increase within each stage of said pump.

2. A pump assembly as defined in claim 1 wherein each said slot has a cross sectional area sufiicient to receive only one of said leads.

3. A pump assembly as defined in claim 1 including a cylindrical shell surrounding said pump cases for protecting said cases and said leads within said slots.

4. A pump assembly as defined in claim 1 wherein said outer wall of each said pump case is substantially uniform in thickness and has a plurality of circumferentially spaced axially extending U-shaped portions projecting inwardly to define said slots, and said diffuser means comprising an annular diffuser disposed within each said case and having a plurality of peripherally paced vanes projecting outwardly between said U-shaped portions to define a corresponding plurality of radially diffusing said passageways between said slots.

5. A pump assembly as defined in claim 4 wherein said vanes of each said diffuser each includes means defining a cavity therein for receiving the adjacent said U-shaped portion of the corresponding said case to prevent relative rotation between each said diffuser and its corresponding said case.

6. A pump assembly as defined in claim 4 wherein said vanes of each said diffuser each includes integral first and second portions, said first portion of each said vane extending adjacent said outer wall between said U-shaped portions and radially overlapping said second portion of an adjacent said vane to define a volute-shaped said passageway.

7. A pump assembly as defined in claim 4 including means defining a corresponding plurality of peripheral spaced recesses within each said dilfuser between said vanes for receiving said U-shaped portions of the corresponding said case, and each said recess forming a generally axially extending passageway adjacent one of said U-shaped portions and connected to the corresponding said radially diffusing passageway.

8. A pump assembly as defined in claim 7 including means defining a corresponding plurality of generally radially extending passageways within each said case connected to the coresponding said axially extending said passageways, and said latter passageways each having an increasing cross-sectional area in an inwardly direction to provide additional diffusing.

9. A pump assembly as defined in claim 4 wherein each said case and the corresponding said diffuser include an annular radial wall arranged in parallel spaced relation; and a plurality of V-shped ribs annularly arranged between each adjacent pair of corresponding said walls to define a corresponding plurality of generally radially extending diffusing passageways.

10. A pump assembly as defined in claim 4 including means defining a peripheral external shoulder extending around said outer Wall and corresponding said U-shaped portions of each said case for receiving the adjacent said case in interfitting nested relation and thereby provide positive alignment of said cases.

11. A pump assembly as defined in claim 1 wherein said slots are uniformly spaced around the periphery of said cases.

References Cited UNITED STATES PATENTS 2,853,949 9/1958 Schaefer .10387 3,115,840 12/1963 Feltus 10387 ROBERT M. WALKER, Primary Examiner.

US. Cl. X.R.

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