US2787962A - Impeller for centrifugal pump - Google Patents

Description

April 9, 1957 INVENTOR. EDWARD lflSM/TH BY RIC/1E), WA 775, EDGERTO/VJ M$NENNY A TTOENEYS United States Patent Olfice Patented Apr. 9, 1957 IMPELLER FOR CENTRIFUGAL PUMP Edward M. Smith, Mansfield, Ohio, assignor to German- Rupp Industries, Inc., Bellville, Ohio, a corporation of Ohio Application January 4, 1954, Serial N 0. 401,841

3 Claims. (Cl. 103-103) This invention relates generally to centrifugal pumps and is particularly concerned with a new impeller for pumping liquids containing fibers, threads and the like.

My co-pending application, Serial No. 179,767, filed August 16, 1950, now Patent No. 2,672,822, discloses a centrifugal pump equipped with an impeller including oppositely projecting, resilient, defiectable blades. it has been found that the efiiciency of pumps equipped with that type of impeller has been maintained through a relatively Wide range of operation due to deflection of the blades but that fibers, threads, ravelings and the like which are often present in the water from washing machines tend to wind around the impeller shaft and eventually to plug the pump passages and prevent adequate flow of water. The present invention aims to retain the advantages and avoid the disadvantages of the prior impeller and attains that object by means of a new combination of elements in which the elements act in cooperation to produce a new conjoint result which is different from that produced by the separate elements.

The present invention will be better understood by those skilled in the art from the following specification and the drawing accompanying and forming a part thereof, in which:

Fig. 1 is a central sectional view through a centrifugal pump embodying the present invention;

Fig. 2 is an elevational View of the impeller of Fig. 1 taken from the fluid inlet side;

Fig. 3 is an elevational view of the impeller of Figs. 1 and 2 showing the blades in side elevation; and

Fig. 4 is an elevational View of the impeller of Figs. 1 and 2 showing the blades in end elevation.

In Fig. l the pump shown comprises a housing 1 and a back plate 2. The housing 1 has a central inlet pipe 3 and a peripheral tangential outlet pipe 4. The housing l and plate 2 define an impeller chamber 5 which communicates with inlet pipe 3 and also with outlet pipe 4. An impeller is shown in chamber 5 with its shaft projecting through the back plate and through packing 11 carried by the back plate and surrounding the shaft 16 for preventing the passage of fluid out of the pump along shaft 10.

The impeller of Fig. l is shown in more detail in Fig. 2, 3 and 4. This impeller consists of a relatively inflexible disk and a resilient member comprising an elongated hub is? having blades 17 extending therefrom approximately in opposite directions with edges or lips 18 which are quite flexible and bear against the adjacent surface of disk 15 when assembled therewith. The hub 16 is provided with a shoulder 1? to bear against the other side of disk 15 and also has a projecting shaft it] which may be screw-threaded interiorly as at 21 for attachment to a drive shaft.

When the disk 15 is assembled with the hub and blades substantially as shown in Fig. 4, the flexible lips 18 of the blades 17 will initially engage snugly against the disk and will be pressed into closer engagement with the impeller, when it rotates, by reason of a pressure of water against the lips 18. During rotation of the impeller the free ends of the blade 17 may bend and move relative to the disk, that is, the water pressure exerted against the blades during their rotation may bend the blades backwardly to a limited extent. This flexing of the blades permits the impeller to conform to the pumping requirements without reducing the etficiency of the pumps or decreasing the snug fit between the blades and the disk. In this manner the blades may alter their configuration under different pumping conditions and yet maintain the efiiciency approximately constant at all tunes.

Since the disk is diametrically coextensive with the impeller there is little, if any, tendency or opportunity for threads, ravelings, and the like, to approach the hub 20 of the impeller and hence the previous disadvantage of wrapping these objects around the impeller is avoided. This result follows from the fact that the water which enters the impeller chamber through pipe 3 is immediately subjected to forces directing it outwardly toward the periphery of the chamber and discharging it tangential through pipe 4.

From the foregoing description it will be understood that the disk cooperates with the impeller blades to prevent threads, ravelings, and the like, from coming into contact with shaft 20 of the impeller; and, also that the disk 15, blades 17 and lips 18 cooperate to maintain close fitting contact between the blades and disk While permitting limited movement of the blades relative to the disk under varying pumping conditions without serious impairment of efiiciency.

Having thus described the present invention so that others skilled in the art may be able to practice the same, I state that what I desire to secure by Letters Patent is defined in What is claimed.

What is claimed is:

1. An impeller for a centrifugal pump comprising an elongated hub for attachment to a drive shaft, a shoulder on said hub, a disk surrounding said hub with one side bearing against said shoulder, blades of resilient material extending outwardly from said hub and having flexible lips extending longitudinally of the blades and pressing against the other surface of said disk and urging it against said shoulder.

2. An impeller for a centrifugal pump comprising an elongated hub for attachment to a drive shaft, a shoulder on said hub, a disk surrounding said hub with one side bearing against said shoulder, blades of resilient material extending outwardly from said hub and having flexible longitudinal extending lips pressing against and distorted by contact with the other surface of said disk, the outer ends of said blades being bendable and movable to a limited extent relative to said'disk while maintaining the lips in contact with the disk.

3. A centrifugal pump comprising a housing defining an impeller chamber having inlet and outlet openings and an impeller rotatable in said chamber, said impeller comprising an elongated hub for attachment to a drive shaft, a shoulder on said hub, a disk surrounding said hub with one side bearing against said shoulder, blades of resilient material extending outwardly from said hub and having flexible longitudinally extending lips pressing References Cited in the file of this patent UNITED STATES PATENTS Jandasek Aug. 27, 1946 Lehman July 7, 1953

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