Centrifugal pump system

March 19, 1963

3,081,981

C. J. KUNZ

CENTRIFUGAL PUMP SYSTEM

Filed Feb. 17, 1959

Sheets-Sheet 1

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C. J. KUNZ

CENTRIFUGAL PUMP SYSTEM

March 19, 1963

Filed Feb. 17, 1959

3,081,981

Sheets-Sheet 2

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CHARLES J. KUNZ

INVENTOR.

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ATTORNEYS

United States Patent Office

3,081,981

Patented Mar. 19, 1963 ¹ '

081 981 CENTRIFUGAL’PUMP SYSTEM

Charles J. Kunz, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey

Filed Feb. 17, 1959, Ser. No. 793,756 7 Claims. (Cl. 259—96)

This mvention relates generally to pumps, and more specifically to a centrifugal pump system for recirculating processing solution, or the like, in a processing tank.

Centrifugal pumps of the type having a cavity containing liquid above and in register with the impeller housing to prevent air from leaking into the system and to eliminate the need for a shaft packing gland are well known in the art. A pump of this type is described in U.S. Patent No. 1,295,621, W. A. Sirnond. The primary disadvantages of pumps and pumping systems of this type are that they are of relatively complicated construction, thereby increasing the criticality of the manufacturing tolerances involved, increasing the cost of manufacture, and providing a pump system that is difficult to assemble and disassemble without necessitating the aid of special equipment. Applicant’s improved pump system is believed to obviate these disadvantages of prior known pump systems.

Therefore, one of the primary objects of this invention is to provide an improved centrifugal pump system that is of simple design and construction, thoroughly reliable and efficient in operation, and economical to manufacture.

Another object of this invention is to provide an improved centrifugal pump system for recirculating a processing solution in a processing machine in which the pump may be rapidly assembled and disassembled without the aid of special equipment. &lt;

Still another object of the invention is to provide ; an improved centrifugal pump.

A more specific object of the invention is to provide an improved centrifugal pump having a unitary pump assembly of novel design and construction adapted to be readily inserted into and removed from the pump housing.

Objects and advantages other than those set forth above will be apparent from the following description when read in connection with the accompanying drawings, in which:

FIG. 1 is a side elevation view partially in . section, and with portions thereof broken away, of a pump system constructed in accordance with a preferred embodiment of the invention for recirculating a solution within a processing tank; and

FIG. 2 is a perspective view of the pump assembly with a portion thereof broken away. :

As shown in the drawings, a centrifugal pump system is disclosed for recirculating a processing solution 2 or the like in a processing tank 3 to assure adequate agitation and mixing of the processing solution. The pump system essentially comprises a housing assembly 4 having an upper cylindrical housing 5 provided at its lower end with an internal annular, inwardly extending ridge 6.

The ridge 6 has an annular beveled edge 7 at one end merging into the inner surface 8 of upper housing 5, and its other end merging into an annular seat portion 9. A lower impeller housing ,11 is formed integrally with upper housing 5 and is provided with an inlet 12 and an outlet 13. A conduit 14 connects a tap 15 on tank 3 to pump inlet 12. Another conduit 16 connects pump outlet 13 to another tap 17 on tank 3 to provide a closed hydraulic path. The upper housing 5 and tank 3 are each provided with a boss 18, 19 respectively having threaded openings connected by a threaded tube 21 to provide hydraulic communication between upper housing 5 and tank 3 permitting liquid 2 introduced into tank 3 through inlet 22 to enter upper housing 5 and seek a common level in both housing 5 and tank 3.

The centrifugal pump system further includes a pump assembly 23 as seen in FIG. 2 which is adapted to be received by housing assembly 5 as seen in FIG. 1. The pump assembly 23 comprises an electric motor 24 of any suitable type having a cap 25 secured to the base thereof by screws 26. The cap 25 is substantially circular to conform to the inner surface 8 of upper housing 5 and to be received thereby, and has a positioning lug 27 radially extending therefrom as best seen in FIG. 2 receivable by a slot 30 in upper housing 5. The lugand-slot connection 27, 30 cooperates to prevent rotation of pump assembly 23 relative to housing assembly 4. A shaft 28 extends through a central opening formed by cap 25 and has one end drivingly connected to motor 24 and the opposite end secured to an impeller 29 shown as a rectangularly shaped blade. A cover for closing off the open end of impeller housing 11 is shown as a cylindrical disk 31 adapted in an operative position to bear on seat portion 9 as seen in FIG. 1. The disk 31 has a peripheral groove 32 for receiving an O ring 33 of rubber or the like which cooperates with annular ridge 6 in the operative position to divide housing assembly 4 into upper housing 5 which forms a liquid receiving cavity 34, and impeller housing 11 which forms a cavity 35 for receiving impeller 29. The disk 31 is provided with a central bearing 36 for rotatably supporting shaft 28. The cap 25 and disk 31 are further provided with annular, concentric cups or projections 37, 38, respectively, for receiving opposite ends of a cylindrical tube 39. The tube 39 has an opening 41 near one end to provide hydraulic communication between its interior and cavity 34 so that the liquid entering tube 39 can prevent air from leaking past bearing 36 into cavity 35. The tube 39 also serves as a strengthening member by rigidly connecting disk 31 to cap 35, and further prevents axial displacement of disk 31 on shaft 28.

A fastening device for releasably securing pump assembly 23 to housing assembly 4 after the pump assembly has been disposed therein and moved into the operative position as seen in FIG. 1, comprises a substantially U-shaped spring member 42 constructed of wire and having its ends 43 extending through openings formed in upper housing 5 and bent to prevent withdrawal therefrom. The spring 42 is pivoted upwardly into a substantially vertical position with its cross bar 44 urged into engagement with the top of a projection 45 formed by motor 24. In this position, spring 42 is under tension _5g tending to urge disk 31 of pump assembly 23 downwardly into engagement with seat portion 9 of housing assembly 4.

In the operation of this invention, pump assembly 23, as seen in FIG. 2, is inserted in cavity 34 of housing 0q assembly 4. There is no initial resistance to the downward movement of pump assembly 23 since the inner diameter of upper housing 5 is greater than the outer diameter of O ring 33. Further inward movement of pump assembly 23 into its operative position causes O 65 ring 33, which has a greater outer diameter than the inner diameter of annular ridge 6, to strike beveled portion 7 which tends to cam O ring 33 radially inwardly partially flattening it and guiding it into sealing engagement with ridge 6. The downward movement of pump assembly 70 23 is guided by the operator so that lug 27 is in register :,081,981 ³ with slot 30 in upper housing 5 and is received thereby when pump assembly 23 is in its operative position. The spring 42 is moved upwardly and cross bar 42 thereof urged on top of motor projection 45 for releasably securing pump assembly 23 to housing assembly 4. Energization of motor 24 causes impeller 29 to rotate, drawing liquid or solution 2 out of tank 3 through tap 15, conduit 14 and pump inlet 12 into cavity 35 and expelling it through outlet 13, conduit 16 and tap 17 back into tank 3. This recirculation of the tank liquid assures adequate agitation and mixing of solution 2 contained in tank 3.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.