US2934023A - Centrifugal pumps - Google Patents

Description

pri 26, 1960 R. c. LAMKIN ET AL CENTRIFUGAL PUMPS 2 Sheets-Sheet l Filed Dec. 31, 1956 TUHNEY.

April 26, 1960 R. c. LAMKIN ET AL CENTRIFUGAL PUMPS 2 Sheets-Shea?l 2 Filed Deo. 31, 1956 United States APatent:

cnNrRmUGAL PUMPS Richard C. Lamkin, Skaneateles, Charles R. Stelljes, Fayetteville, and John F. Etherington, Syracuse, N.Y., assignors to The Murray Corporation of America, Syracuse, N.Y., a corporation of Delaware Application December' 31, 1956, serial No. 631,956

z claims. (c1. s-10s) This invention relates to pumps and more particularly to centrifugal pumps adapted for use, for example, in laundry appliances such as washing machines, washing and drying machine combinations, or dryers employing condensing wa-ter.

In laundry appliances of the above character, the waste water is generally laden with soapy constituents, solids, lint and the like, and in addition may contain foreign matter such as buttons, paper, small pocket items and the like, inadvertently introduced into the appliance, It is desirable that a pump be so constituted as to handle and eliminate all such foreign matter, without clogging or jamming, since, the sequence of automatic operations in such appliances depends upon the satisfactory elimination of wash and rinse water as Well as condensate within the periods of time allotted thereto.

More particularly the invention is directed to a centrifugal pump having a minimum number of impeller blades, and having an inlet eccentric of the impeller axis and swept by the blades, together with a back wall behind the impeller provided with spiral tracking to cause radial elimination of solids tending to collect behind the impeller.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when ltaken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings, wherein like reference characters indicate like parts:

-Figure 1 is a longitudinal axial section through the Pump;

Figure 2 is a transverse section taken substantially on the line 2 2 of Figure l, and

Figure 3 is an end elevation with parts broken away.

In the drawings there is shown a pump casing comprising two complementary casing members 29 and 22 which together form a hollow cylindrical impeller cavity 24. The left hand member 20, is provided with a boss 26 t0 which is attached, by screws 27, a ilanged bearing Sleeve 28, the bearing sleeve containing spaced bearings 30 and 32, which support an impeller driving shaft 34. 'I'he riving shaft has a pulley 36 at one end and a threaded stem 38 adapted to thread into a corresponding threaded recess 40 of the impeller shaft proper 42. The impeller, as shown in Figure 2, rotates in the direction of arrow A, and the drive through the threaded stem therefore requires a left hand thread.

The boss 26 is provided with a seal recess 44, containing an annular seal 46 surrounding the impeller shaft 42, such seal being axially compressed by a sleeve 48 and coil spring 50, acting through a washer 52 and O rings 54. The coil spring is provided with a radial end extension 55 lying in a transverse slot 56 in the end of sleeve 48.

The pump cavity or chamber face of the member is provided with a peripheral annular shoulder 58 to receive and center the casing member 22. The circular face of the wall within the chamber is provided with a spiral ridge 60 of rectangular section starting centrally beneath the hub 62 of the impeller 64, the ridge spiralling outwardly as indicated in Figure 2, in the direction of rotation of the impeller as indicated by the arrow A. The member 22, completing the pump chamber comprises a cylindrical internal wall 66, and a tangential outlet 68. The wall 70 of the member is provided with an eccentric inlet 72 which is in turn coupled to the sump of the appliance tub 74, by a rubber hose 76. The outlet is provided with an outlet hose 77, and has a llexible rubber or other composition ap valve 78, secured at one side to the end of the outlet 80, as by a small screw 82. The impeller, which may be formed of relatively rigid rubber like composition, comprises an integral hub and opposed rectangular tangential blades. By reason of the eccentricity of the inlet 72, the blades sweep the inlet on each rotation so as to drag any material into the pump,

` with a chopper like eiect, to break up lint and the like as it is drawn in. The impeller, cooperating with the spiral ridge 60, prevents lint and other extraneous matter from balling up, around the shaft, and acts to constantly break up the foreign matter and urge it radially outward for discharge through the outlet 68. n

The outlet with its check valve 78, prevents oscillatory ow of water in the outlet hose, after the tub has been drained, it being understood that a certain amount of water is usually trapped in the outlet hose, after the pump has drained the tub. Such residual water would have a tendency to surge back and -forth into the pump chamber, creating disagreeable noise. Further, such valve prevents any possibility of reverse syphon should the pump stop and the outlet hose end be submerged in water in a set tub or the lige at a higher level.

The eccentric inlet, and spiral ridge provide for the expeditious handling of the wash water, and condensing water, and clogging of the pump, from extraneous matter contained in such water is eliminated by the inter-action of the impeller in cooperation with the eccentric inlet, cylindrical chamber wall and the spiral ridge of the back wall.

While a single embodiment of the invention has been illustrated and described, it is to be understood that the invention is not limited thereto. As various changes in the construction and arrangement may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

l. In a centrifugal pump comprising a pump casing having axially spaced planar front and rear walls joined by a peripheral cylindrical marginal wall defining a pump chamber, a shaft extending through said rear wall sub stantially at the center thereof, a rotary impeller having two substantially radial blades with rectangular sides having planar radial end faces normal to the axis of impeller rotation aiiixed to said shaft, said blades being adapted to closely sweep said chamber walls, and a spiral ridge of substantially uniform height in said rear wall defining a iow passage therein that commences adjacent the impeller shaft and extends substantially to the outer margin of said rear wall, said ridge gradually increasing in radius in the direction of impeller rotation, and said blades being of a radial length extending substantially to the outer margin of said rear wall whereby the blades individually sweep the entire length of said ridge and move materials therein along said groove toward the marginal edge of said rear wall.

2. In a centrifugal pump comprising a pump casing hav- Paie-afgaan. 26', issol m5339119 sradplanarffront and rear'walls i'oined by a peripheral cylindrical marginal wall dening arpnplp pump chamber in the frontwall, a tangential outlet in the .p eripheralwall, a shaft extending through said4 Yrear.'

hying'two substantially radiallblades with rectangular sides having planar radial end faces normal to the axis 0fimpeller rt'pta'tio'nY aixed to said shaft, said blades being adaptedto closely sweep said chamber walls, and a spiral ridg'e of substantially uniform height in said rear wall delining aow passage therein'that commences adjacent the iipellei" shaft and` extends substantially'to the outer.

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UNITED STATESA PATENTS- Webb Sept. 12, Papillon July 2, Sperry Nov. 28, Lehman Y Iuly 7, Kreithman Mar. 9, De Moss Sept. 14,

' FOREIGN PATENTS Switzerland Jan. 22, Australia .A Mar. 4, Germany-; Jan. 16, Great Britain 2-,..' i .j. July 7, France VMay 19, Great Britain Nov. 13, Germany e ,Julyv 24,

France ...7.,. f.w Nov. '16,v

References'Cltell` in the le of this patent 7

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