US3216361A - Pumps - Google Patents

Description

R. C. LEFF Nov. 9, 1965 PUMPS Filed Dec. 27, 1963 7 6 4 4% I- I 60 m d a a n U 7 2 4 5 8% 3 O 2 9 2 a FIG-5 4 a 4 a W a O O 3 O o 3 8 4 w 00 0 0o Q0 R @s mw BE m VL 0 WC. T T T A R E B 0 RM an a Z 3 0 Ta 1 a v6 9 8 I I a 9% a United States Patent Ohio Filed Dec. 27, 1963, Ser. No. 333,965 4 Claims. (Cl. 103-111) This invention relates to pumps.

The invention has special relation to sump pumps and the like wherein an impeller operates at the end of its drive shaft within a pumping chamber. It is important for optimum efficiency with such pumps that the impeller be held in relatively closely spaced relation with the wall of the pumping chamber wherein the suction inlet is located, particularly in the case of an open faced vaned impeller. At the same time, it is desirable that pumps of this type be capable of production at relatively low unit cost, with relatively wide manufacturing tolerances, but that they be capable of a long satisfactory operating life under even relatively severe service conditions.

It is a primary object of the present invention to provide a pump of the general type outlined above wherein the impeller and associated parts are of novel structure making possible quick and easy adjustment of the impeller on its drive shaft at the time of final assembly, and also assuring that the impeller will be retained in its accurately established position 'during operation of the pump.

It is a particular object of the invention to provide a pump construction as outlined in the preceding paragraph wherein the impeller is infinitely adjustable within a sufiiciently large range to compensate for even relatively wide tolerances in the initial manufacture of its component parts, and which is accordingly adaptable to mass production at relatively low unit cost.

It is also an object of the invention to provide a pump as outlined above wherein the impeller may be adjusted in the field with the same case as during initial assembly of the pump.

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

In the drawings:

FIG. 1 is a view partly in section and partly in elevation of a pump constructed in accordance with the present invention;

FIG. 2 is a view in bottom plan of the pump of FIG. 1 with the base removed;

P16. 3 is an enlarged fragmentary view in vertical section of a portion of the structure of FIG. 1, showing in detail the construction of the driving shaft and its seal;

FIG. 4 is a fragmentary view in vertical section showing details of the adjustment of the impeller relative to the drive shaft; and

FIG. 5 is a sectional view on the line 55 of FIG. 3 but on a smaller scale than FIG. 3.

Referring to the drawing, which illustrates a preferred embodiment of the present invention, FIG. 1 shows a representative form of a pump which includes a motor section generally designated and a pump section generally designated 12. A motor 14 is positioned within an outer shell 16. On the upper end of the shell 16 is -an upper motor housing 18, and the shell 16 extends at its lower end into a lower housing 20. The upper housing 18, the shell 16 Patented Nov. 9, 1965 and the lower housing 20 are held together in substantially sealed relationship by a plurality of through bolts such as the bolt 22. The upper housing 18, the outer shell 16 and the lower housing 20 alternatively may be joined together by use of an epoxy cement or other suitable means well known in the art.

The motor 14 includes a stator 24 supported by the shell 16 and rotor 25 which is carried by the shaft 26, the upper end of the shaft being supported in the upper housing 18 by a bearing 27 and a retainer 28. The lower end of the shaft 26 carries an impeller 30 provided with a plurality of impeller blades 32, the impeller 30 being secured to the shaft by a lock screw 33 as more fully described hereinafter. The lower end and the intermediate portion of the shaft 26 are supported in a bearing assembly 34, and intermediate the bearing assembly 34 and impeller 30 is a rotary seal assembly 35.

Electric current is supplied to a switch assembly 41 by a conduit 42 and is supplied from the switch assembly 41 to the motor 14 by a conduit 43. The switch assembly 41 includes a diaphragm or other type of switch which is controlled by pressure and/ or by depth of liquid surrounding the pump to operate the motor. Any suitable switch such as a pressure switch or float switch may be utilized to energize the motor 14 in response to the presence of liquid above any predetermined level.

In the bottom end of the pump housing 20 is the impeller chamber or volute chamber 44, which as shown in FIG. 2 is in the form of an eccentric spiral and terminates in an outlet chamber 45. The housing 20 is threaded at 46 above the chamber 45 to receive the discharge pipe 47. The bottom wall 48 of the chambers 44 and 45 is formed by a portion of the base 50 which supports the pump, and which is provided with multiple perforations 51 around its exterior to admit water for entry to the pumping chamber 44 through the impeller inlet opening 52 in the wall 48. A check valve 55 is provided in the housing 20 above the chamber 45 to prevent return of liquid from discharge pipe 47 to the chambers 45 and 44 when the pump is shut off.

Referring now especially to FIGS. 1 and 4, the lower end of the shaft 26 is grooved as at 61, and a spline 62 formed in the internal bore of the impeller 31 cooperates with the groove 61 to secure the impeller 30 against rotation on shaft 26. Means are provided for effecting accurate adjustment of the impeller 31 up and down on the shaft 26. Referring particularly to FIG. 4, the lower end of shaft 26 is formed with a tapped bore 63 for the screw 33, which screw is formed to be elfectively self-locking, as illustrated by the provision therein of a slot 65 into which there is inserted a wedge 66 of nylon or other resilient means establishing a self-locking relation with bore 63. Between the head of the screw 33 and the lower end surface 68 of the impeller 31 is inserted a washer 69.

FIG. 4 shows the impeller 30 in an intermediate position between its uppermost position relative to the shaft 26 and its lowermost position relative thereto. Thus screw 33 may be threaded further into the bore 63 to move the impeller 30 upward on shaft 26, and similarly if screw 33 is backed off in bore 63, the impeller is free to move down the shaft. Resilient means are provided in accordance with the invention for maintaining the impeller in firmly seated position on the washer 69 in all its adjusted positions as now described.

Referring particularly to FIG. 3, the bearing assembly 34 is arranged to form a thrust bearing positively limiting downward movement of the shaft 26. It includes an outer race 70 which is seated on the annular shoulder 71 at the bottom of a counterbore 72 in the lower housing 20. The 'balance of the bearing comprises the usual balls 74 and inner race 75. A snap ring 77 is received in a slot 78 of the shaft 26 and forms a shoulder which seats on the inner race 75 to limit downward movement of the shaft with respect to housing 20.

The rotary seal assembly 35 includes resilient means continuously urging the impeller 30 downwardly against the washer 69. Referring to FIG. 3, the lower housing 20 is provided on its under side with a counterbore 80 in which the stationary seal ring 81 of ceramic or like material is mounted by means of a suitable gasket 82 of neoprene or like material. The rotating seal ring 83 is secured to the shaft 26 by a neoprene diaphragm 85, a metal shell 86, and a neoprene friction seal ring 88 which seals to but is axially movable along shaft 26 and engages the upper end face 89 of the impeller 30. The diaphragm 85 is clamped by a relatively heavy coil spring 90 against the rotating seal ring 83 and the opposed annular flange portion of the shell 86, and the shell 86 includes an inner annular shoulder 91 which seats on ring 88.

The axial thrust of the spring 90 not only maintains the seal members 81 and 83 in running sealing engagement, but it continuously urges the seal ring 88 axially against the impeller end face 89 and thereby urges the impeller downwardly along shaft 26 into firmly seated relation on the washer 69, and this spring force is supplemented by the downward hydraulic force which is developed by the impeller in operation. Since the shaft 26 is held against downward movement by the cooperation of the bearing race 75 and snap ring 77 as described, the ultimate result of this arrangement is that the impeller 30 is always maintained in the accurately spaced relation with the wall 48 which is established by the adjusted position of the screw 33 in the bore 63. The clearance between the impeller and the wall 48 is particularly important for maximum efliciency of the pump when an open impeller 30 is used, as is preferred in this type of pump, and the construction of the invention makes it possible to adjust the impeller vane Within a few thousandths of an inch of wall 48.

The invention offers special advantages in the initial construction and assembly of the pump, particularly in its ease of compensation for manufacturing tolerances. Thus it will be apparent that the overall construction of the pump, including the cast housing 24), sheet metal base 50 and shaft 26, provides a possibility of considerable variations in dimensions. With the use of the invention, however, these parts need be manufactured only within relatively wide tolerances, since when the pump is assembled, the final adjustment of the impeller to the desired accurately spaced relation with the wall 48 is quickly and easily accomplished by application of a screw driver to the screw 33. Since this screw is effectively self-locking, by the provision of the plastic wedge 66, the impeller will hold its adjusted position for a normal operating life without the necessity of subsequent adjustment. At the same time, pumps of the illustrated type. are often required to handle relatively abrasive liquids, and if the impeller should be worn in use to a point where there is too great a clearance between it and the wall 48, it can easily be adjusted in the field with no tool other than a screw driver. Thus the invention provides advantages for maintenance purposes as Well as in the initial construction and assembly of the pump.

While the form of apparatus herein described on stitutes a preferred embodiment of the invention, it is to be understood that this 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. A centrifugal pump adapted to be adjusted after assembly or after an extended period of service to provide optimum pumping efiiciency and for substantially reducing dimensional tolerances during construction of the pump components, comprising a housing defining a pumping chamber, wall means substantially closing said chamber and having an inlet therethrough to said chamber, a drive shaft rotatably supported in said housing and with an end portion thereof projecting into said pumping chamber from the side opposite said wall, a centrifugal open impeller splined for relative axial movement on said end portion of said shaft Within said chamber and having a plurality of vanes extending therefrom toward said wall, means spaced between said housing and said impeller for exerting a biasing force urging said impeller axially on said shaft toward said wall, thrust means connected to said end portion of said shaft for opposing the axial movement of said impeller on said shaft, and means accessible through said inlet for axially adjusting said thrust means in relation to said shaft to position said vanes of said impeller precisely in spaced relationship with said wall for optimum pumping efliciency.

2. A centrifugal pump adapted to be adjusted after assembly or after an extended period of service to provide optimum pumping efliciency and for substantially reducing dimensional tolerances during construction of the pump components, comprising a housing defining a pumping chamber, wall means substantially closing said chamber and having an inlet therethrough to said chamber, a drive shaft rotatably supported in said housing and with an end portion thereof projecting into said pumping chamber from the side opposite said wall, a centrifugal open impeller splined for relative axial movement on said end portion of said shaft within said chamber and having a plurality of vanes extending therefrom toward said wall, a rotary mechanical seal assembly spaced between said impeller and said housing and arranged to form a running seal between said shaft and said housing, spring means arranged to exert a biasing force urging said impeller axially on said shaft toward said wall, thrust means connected to said end portion of said shaft for opposing the axial movement of said impeller on said shaft, and means accessible through said inlet for axially adjusting said thrust means in relation to said shaft to position said vanes of said impeller precisely in spaced relationship with said wall for Optimum pumping efliciency.

3. A centrifugal pump adapted to be adjusted after assembly or after an extended period of service to provide optimum pumping efficiency and for substantially reducing dimensional tolerances during construction of the pump components, comprising a housing defining a pumping chamber,rwall means substantially closing said chamber and having means defining an inlet therethrough to said chamber, a drive shaft rotatably supported in said housing and with an end portion thereof projecting into said pumping chamber from the side opposite said wall, means defining a threaded hole extending axially into said end portion of said shaft, a centrifugal impeller splined for relative axial movement on said end portion of said shaft within said chamber and having a plurality of vanes extending therefrom toward said wall, a rotary mechanical seal assembly spaced between said impeller and said housing and arranged to form a running seal between said shaft and said housing, said seal assembly including spring means arranged to exert a biasing force urging said impeller axially on said shaft toward said wall, a screw engaging in said threaded hole, thrust means associated with said screw for opposing the axial movement of said impeller on said shaft, and said screw including head means accessible through said inlet for axially adjusting said thrust means in relation to said shaft to position said vanes of said impeller precisely in spaced relationship with said wall for optimum pumping efiiciency.

4. A pump as defined in claim 3 wherein said screw is self-locking and includes deformable plastic means engaging the inner surface of said threaded hole to provide for simple axial adjustment of said impeller While assuring that the adjusted position of said impeller in relation to said shaft will remain fixed during operation of the pump.

References Cited by the Examiner UNITED STATES PATENTS 2,669,938 2/54 La Bour 103-111 2,842,063 7/58 Kishline 61:211. 103 103 2,853,020 9/58 Hollinger et a1. 103-111 5 1/63 Spring 103-111 5/63 Culleton 103103 5/63 Danis 103111 5/64 Jennings 103-111 10/64 Van Blarcom 103103 FOREIGN PATENTS 8/60 Canada. 10/58 Italy.

DONLEY J. STOCKING, Primary Examiner. HENRY F. RADUAZO, Examiner.

Claims (1)

1. A CENTRIFUGAL PUMP ADAPTED TO BE ADJUSTED AFTER ASSEMBLY OF AFTER AND EXTENDED PERIOD OF SERVICE TO PROVIDE OPTIMUM PUMPING EFFICIENCY AND FOR SUBSTANTIALLY REDUCING DIMENSIONAL TOLERANCES DURING CONSTRUCTION OF THE PUMP COMPONENTS COMPRISING A HOUSING DEFINING A PUMPING CHAMBER, WALL MEANS SUBSTANTIALLY CLOSING SAID CHAMBER AND HAVING AN INLET THERETHROUGH TO SAID CHAMBER, A DRIVE SHAFT ROTATABLY SUPPORTED IN SAID HOUSING AND WITH AN END PORTION THEREOF PROJECTING INTO SAID PUMPING CHAMBER FROM THE SIDE OPPOSITE SAID WALL, A CENTRIFUGAL OPEN IMPELLER SPLINED FOR RELATIVE AXIAL MOVEMENT ON SAID END PORTION OF SAID SHAFT WITHIN SAID CHAMBER AND HAVING A PLURALITY OF VANES EXTENDING THEREFROM TOWARD SAID WALL, MEANS SPACED BETWEEN SAID HOUSING AND SAID IMPELLER FOR EXERTING A BIASING FORCE URGING SAID IMPELLER

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