US3234886A

US3234886A - Pumps

Info

Publication number: US3234886A
Application number: US375020A
Authority: US
Inventors: Robert C Leff
Original assignee: Tait Manufacturing Co
Current assignee: Tait Manufacturing Co
Priority date: 1964-06-15
Filing date: 1964-06-15
Publication date: 1966-02-15
Anticipated expiration: 1983-02-15

Description

Feb. 15, 1966 R. c. LEFF 3,234,886

PUMPS Filed June 15, 1964 I 20 v INVENTOR. wig ROBERT C. LEFF e0 45 22- BY ATTORNEYS United States Patent Ofiflce 3,234,886 Patented Feb. 15, 1966 Ohio Filed June 15, 1964, Ser. No. 375,020 4 Claims. (Cl. 103-87) This invention relates to submersible pumps, and more particularly, to a submersible motor-pump combination having a novel mechanism for opposing axial thrust developed by the pump, and which in addition provides for a simplified assembly of the motor and pump.

The present invention is particularly adaptable to a submersible pump which is intended for submerging in a well, within the well casing, and which includes a motor mounted below the pump.

It has been determined that the axial thrust which is transferred through the impeller shaft of a centrifugal pump will vary substantially depending upon the overall configuration of the impeller. For example, such factors as whether the impeller has an open or closed face, the number and configuration of the vanes, and the clearances between the impeller and the pump housing are some of the factors which must be considered when designing a centrifugal pump and which influence the resulting thrust roduced by the pump.

In a multi-stage centrifugal pump, the type commonly employed for submersible well pumps, the impellers may be designed for maximum pump efficiency at a rated flow capacity, as for example, 60 g.p.m. When the pump is operated at this capacity, the resultant thrust of the pump shaft, including the weight of the shaft and impellers, may be downwardly, that is, opposite in direction to the flow of water into the impellers. However, it is possible that when this same submersible pump is operated at some point above the rated flow capacity, which frequently is the case, that the resulting thrust developed by the pump and transferred through the pump shaft may reverse and be in an upward direction, the same as the flow of water into the eye of the centrifugal impellers. While it is important to provide some means for opposing this upward thrust to prevent wear in the motor and pump, it also is highly desirable for eflicient manufacturing and servicing operations that a submersible pump be so constructed for easy assembly and disassembly.

Accordingly, it is a primary object of the present invention to provide a submersible pump unit with a novel mechanism which opposes the upward axial thrust developed by the pump, without transferring any portion of the thrust to the motor shaft, and which, in addition, provides for simplified assembly and disassembly of the unit.

As another object, the present invention provides a mechanism for opposing the upward axial thrust developed by a multi-stage submersible pump and which mechanism is economical to manufacture.

It is also an object of the present invention to provide a submersible multi-stage centrifugal pump which is so constructed to include a self-lubricating mechanism to oppose the axial thrust transferred through the pump shaft in a direction which is the same as that of the water flowing, up through the pump stages.

Still a further object of the invention is to provide a submerisible water pump with a mechanism for opposing the upward axial thrust produced by the pump shaft, and which mechanism is so constructed to provide a long-life by being lubricated by the water pumped, without tending to come into contact with sand or other abrasive material which may be dispersed within the water.

Further objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.

In the drawin FIG. 1 is an elevational view illustrating a submersible pump assembly of the type to which the present invention relates;

FIG. 2 is an enlarged fragmentary view in axial section through the connect-ion between the pump and motor portions of the assembly of FIG. 1, the view being a section along the line 2-2 of FIG. 3;

FIG. 3 is a radial section on the line 33 of FIG. 2;.

FIG. 4 is an enlarged fragmentary view similar to FIG. 2, but showing a second embodiment of the present invention; and

FIG. 5 is an enlarged fragmentary view similar to FIG. 4, but showing a third embodiment of the invention.

Referring to the drawing, which illustrates preferred embodiments of the invention, the submersible pump assembly shown in FIG. 1 includes a motor casing 10, a multi-stage pump housing 12, and an intake housing 14 which connects the pump housing 12 to the motor casing 10. Surrounding the intake housing 14 is a cylindrical screen 16 through which the water flows into the pump; The cable 18 is provided to connect the motor to a suitable electrical source and is shielded by the guard 19.

As can be seen from FIG. 2, the intake housing 14 includes a base flange 20 which is rigidly mounted to the end bracket 22 of the motor casing 10 as by cap screws 24. Extending upwardly from the base flange 20, and forming part of the intake housing 14, is a tubular portion 26 having a reduced top portion 27. A sleeve-type bearing 28 is mounted within the top portion 27 and ro-i tatably supports the end portion of a pump shaft 30. Extending radially outward from the tubular portion 26 and the top portion 27 are three equally spaced ribs 31 which define inlet passageways 32 and serve to support an annular-shaped top flange 33. The flange 33 is partially inserted within the pump housing 12 for alignment purposes and is rigidly mounted thereto by the cap screws 35.

The bottom centrifugal impeller 37 shown fragmentarily in FIG. 2 is typical of the other impellers in housing 12 and is mounted to the pump shaft 30 by a suitable locking sleeve 40. Surrounding the inlet portion 41 of the impeller 37 is a clearance ring 43 which is press fitted into the top flange 33 of the intake housing 14 and serves to provide a small annular clearance between the impeller and the intake housing. As mentioned above, several impellers 37 are similarly mounted on the shaft 30 in stacked relationship and cooperate with the pump housing 12 to form a multiple stage centrifugal pump.

Projecting upwardly from the motor end bracket 22 is a motor shaft 45 which is adapted to drive the pump shaft 30 positively through a tubular coupling 50,. Preferably, the coupling is connected to the motor shaft 45 by an internal spline 52 which engages a corresponding spline 54 formed along the end of the motor shaft 45, and allows the coupling 50 to move axially along the motor shaft 45.

The upper portion of coupling 50 includes a somewhat smaller opening 55 which is adapted to be mounted on the end of the pump shaft 30. This smaller opening 55 provides an internal shoulder 56 which is adjoined by an annular relief 57 to allow for forming of the spline 52. A hollow retaining member 60 is attached to the end of the pump shaft 30 by the cap screw 61 and serves as a means to prevent the shoulder 56 of the coupling 50 from moving downwardly past the end of the pump shaft 30. Spaced between the bottom of the retaining member 60 and the motor shaft 45 is a hardened spacer washer 62 which prevents the retaining member 60 from deforming the end of the motor shaft 45 when the coupling 50 moves axially on the motor shaft 45 during operation. To accomplish the positive drive between the motor shaft 45 3 and the pump shaft 30, another spline 65 is provided on the bottom end of the pump shaft 30 and engages with a corresponding spline 66 formed within the smaller opening 55 of the coupling 50.

An annular stationary thrust washer 711 is mounted within the top of the tubular portion 26, and preferably is press fitted therein. Between this stationary thrust washer 70 and the coupling 50 is a rotary thrust washer 71 which is adapted to rotate with the pump shaft 31) but is free to move axially on the pump shaft within the available axial clearance provided above the coupling 50. Sandwiched between the rotary thrust washer 71 and the stationary thrust washer 70 is a middle wear washer 72 which is adapted to rotate freely about the pump shaft 30. Preferably, the Wear washer 72 is formed from a low friction material, as for example, a fluorocarbon resin of the type sold under the trade name Teflon.

When the centrifugal pump is operated under such conditions that the resulting thrust on the pump shaft 30 is in an upward direction, away from the motor shaft 45, it will be seen that the coupling 50 will move upwardly with the pump shaft 30. In so doing, the top face of the coupling 50 will engage the rotary thrust washer 71, and the upward thrust is transferred to the stationary thrust washer 70 through the wear washer 72. By this arrangement, the upward thrust is evenly distributed about the radial faces of the wear washer 72 and thereby provides an effective and enduring means for opposing the upward thrust developed by the pump. Since the coupling 50 is free to move axially on the motor shaft 45, it will be seen that none of the upward axial thrust is transferred to the motor shaft. The motor may be provided however, with a suitable bearing (not shown) which will oppose any dgvnward thrust by the pump shaft against the motor 5 a t.

Since it is possible for water to enter within the tubular portion 26 through the Clearance between the bearing 28 and the pump shaft 30, in normal operation the tubular portion 26 will be filled with water which will provide a lubricant to the radial faces of the wear washer 72. Due to the small clearance, however, sand and similar foreign particles are excluded.

In the embodiment of the invention shown in FIG. 4, the pump shaft 30' and the motor shaft 45' are of the same diameter. The coupling 30 accordingly includes one continuous spline connection 81, rather than two separate splines of different sizes employed in the coupling 50, and it includes an internal groove 82 which contains a retainmg ring 85 which serves the same purpose as the internal shoulder 56 in the coupling 50. As provided by the spline connection 81, the coupling 80 is free to move axially on the motor shaft 45 in the same manner as described above for the coupling 50, and the part 60' and several washers '70, 71' and 72' may be essentially the same as the similarly numbered parts in FIG. 2. Also shown is an opening 87 within the bottom of the tubular portion 26' which may be provided to allow water to enter within for lubrieating the wear washer 72. Since there is only one opening, however, there is no flow of water which could bring sand, or the like, in contact with the thrust and wear washers during operation.

According to another embodiment of the invention, as shown in FIG. 5, the coupling 90 is formed with an internally stepped dividing wall 92 which defines on one end a shoulder 94 which is held firmly against the end of the pump shaft 30" by the cap screw 61. Another shoulder 96 which is defined by the other end of the dividing wall 92 serves to transfer any downward axial thrust, developed by the pump shaft 311", to the motor shaft 45". Preferably the hardened fiat spacer washer 62 is provided to prevent the shoulder 96 from deforming the end of the softer motor shaft 45" as the coupling 90, moves axially on the motor shaft 45". The

spline connections

100 and 101 provide the positive drive between he motor shaft 4.5" an pump shaft 36" in the 4. same manner as described above for coupling 50. Similarly, the thrust washers 76' and 71" and the wear washer 72" serve to oppose the upward axial thrust produced by the pump, as described above.

It can be seen from the above description that the mechanism of the invention may easily be assembled and disassembled if the need should arise. For example, to remove the motor casing from the inlet housing, it is only necessary to remove the screen 16, the cap screws 24 and the cord guard 19. Due to the sliding spline connection between the motor shaft and the coupling 50, the motor may then simply be moved axially apart from the inlet housing 14. Then to remove part of the mechanism which opposes the upward thrust developed by the pump, it is only necessary to remove the one cap screw 61, which allows the retaining member 611, coupling 5%), rotary thrust washer 71 and the wear washer 72 to be removed. The other part of the mechanism, including the intake housing 14 and the stationary thrust washer may be disassembled simply by removing the cap screws 35. To assemble the mechanism, the above procedure is merely reversed.

As a result of the arrangement of the mechanism of the invention, a submersible pump containing the mechanism not only provides the feature of easy assembly and disassembly, but combines the feature of having means for opposing the upward thrust developed by the pump without transferring any portion of the thrust to the motor shaft.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms 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. A submersible pump comprising a motor having a submersible casing and including a projecting motor shaft, an inlet housing rigidly mounted on said casing, a multistage pump housing rigidly connected to said inlet housing, a pump shaft rotatably mounted in a bearing supported within said inlet housing and adapted to be driven by said motor shaft, a plurality of impellers mounted on said pump shaft in spaced relationship with said pump housing, a tubular coupling having a splined connection to said motor shaft to provide for relative axial movement of said coupling on said motor shaft, means forming a shoulder within said coupling, means fastened to said pump shaft and adapted to engage said shoulder to cause said coupling to move axially with said pump shaft, and thrust opposing means mounted around said pump shaft between said coupling and the adjacent portion of said inlet housing to oppose the axial thrust of said pump shaft away from said motor shaft.

2. A submersible pump comprising a motor having a submersible casing and including a projecting motor shaft, an inlet housing rigidly mounted on said casing, a multistage pump housing rigidly connected to said inlet housing, a pump shaft rotatably mounted in a bearing sup ported within said inlet housing and adapted to be driven by said motor shaft, a plurality of impellers mounted on said pump shaft in spaced relationship with said pump housing, a tubular coupling having a splined connection to said motor shaft to provide for relative axial movement of said coupling on said motor shaft, means forming a shoulder within said coupling, a retaining means fastened to said pump shaft and adapted to engage said shoulder to provide for movement of said coupling with said pump shaft, a rotary thrust washer mounted on said pump shaft and movable axially by said coupling, and a stationary thrust washer mounted on said inlet housing and adapted to oppose the axial thrust transferred through said rotary thrust washer by said pump shaft.

3. A submersible pump comprising a motor having a submersible casing and including a projectiirg motor shaft,

an inlet housing rigidly mounted on said casing, a multistage pump housing rigidly connected to said inlet housing, a pump shaft rotatably mounted in a bearing supported within said inlet housing and adapted to be driven by said motor shaft, a plurality of impellers mounted on said pump shaft in spaced relationship with said pump housing, a tubular coupling having a splined connection to said motor shaft to provide for relative axial movement of said coupling on said motor shaft, means forming a shoulder within said coupling, a retaining means fastened to said pump shaft and adapted to engage said shoulder to provide for axial movement of said coupling with said pump shaft, a rotary thrust washer mounted on said pump shaft and movable axially by said coupling, a stationary thrust washer mounted on said inlet housing and adapted to oppose the axial thrust transferred through said rotary thrust washer by said pump shaft, and a wear washer loosely mounted on said pump shaft and spaced between said stationary thrust washer and said rotary thrust washer to provide both of said thrust washers with resistance to wear.

4. A submersible pump comprising a motor having a submersible casing and including a projecting motor shaft, an inlet housing rigidly mounted on said casing, a multistage pump housing rigidly connected to said inlet housing, a pump shaft rotatably mounted in a bearing supported within said inlet housing and adapted to be driven by said motor shaft, a plurality of impellers mounted on said pump shaft in spaced relationship with said pump housing, a tubular coupling having a splined connection to said motor shaft to provide for relative axial movement of said coupling on said motor shaft, means forming a shoulder within said coupling, a retaining means fastened to said pump shaft and adapted to engage said shoulder to provide for movement of said coupling with said pump shaft, a rotary thrust washer mounted on said pump shaft and movable axially by said coupling, a stationary thrust washer mounted on said inlet housing and adapted to oppose the axial thrust transferred through said rotary thrust washer by said pump shaft, a wear washer loosely mounted on said pump shaft and spaced between said stationary thrust washer and said rotary thrust washer to provide both of said thrust washers with resistance to wear, and means forming an opening within said tubular portion of said inlet housing to admit pumping fluid to lubricate said thrust and wear washers.

References Cited by the Examiner UNITED STATES PATENTS 2,960,937 11/1960 Wright et a1 103-408 X 3,025,800 3/1962 Wolfe et al 103-87 3,115,840 12/1963 Feltus 10387 3,154,019 10/1964 Hoyt 103-108 X ROBERT M. WALKER, Primary Examiner,

Claims

1. A SUBMERSIBLE PUMP COMPRISING A MOTOR HAVING A SUBMERSIBLE CASING AND INCLUDING A PROJECTING MOTOR SHAFT, AN INLET HOUSING RIGIDLY MOUNTED ON SAID CASING, A MULTISTAGE PUMP HOUSING RIGIDLY CONNECTED TO SAID INLET HOUSING, A PUMP SHAFT ROTATABLY MOUNTED IN A BEARING SUPPORTED WITHIN SAID INLET HOUSING SAID ADAPTED TO BE DRIVEN BY SAID MOTOR SHAFT, A PLURALITY OF IMPELLERS MOUNTED ON SAID PUMP SHAFT IN SPACED RELATIONSHIP WITH SAID PUMP HOUSING, A TUBULAR COUPLING HAVING A SPLINED CONNECTION TO SAID MOTOR SHAFT TO PROVIDE FOR RELATIVE AXIAL MOVEMENT OF SAID COUPLING ON SAID MOTOR SHAFT, MEANS FORMING A SHOULDER WITHIN SAID COUPLING, MEANS FASTENED TO SAID PUMP SHAFT AND ADAPTED TO ENGAGE SAID SHOULDER TO CAUSE SAID COUPLING TO MOVE AXIALLY WITH SAID PUMP SHAFT, AND THRUST OPPOSING MEANS MOUNTED AROUND SAID PUMP SHAFT BETWEEN SAID COUPLING AND THE ADJACENT PORTION OF SAID INLET HOUSING THE OPPOSE THE AXIAL THRUST OF SAID PUMP SHAFT AWAY FROM SAID MOTOR SHAFT.