US2671408A - Pump - Google Patents

Description

arch 1954 M. A. KREiTCHMAN PUMP 2 Sheets-Sheet 1 Filed March 10, 194'? ATTORNEY March 9, 1954 M. A. KREITCHMAN PUMP 2 Sheets-Sheet 2 Filed March 10, 1947 INVENTOR' Adfiedzzzazz aiy/gyfiflil Patented Mar. 9, 1 954 PUMP Morton A. Kreitchman, Irvington, N. 5., assignor to International Telephone and Telegraph Corporation, a corporation of Maryland Application March 10, 1947, Serial No. 733,682

6 Claims. 1

The present invention relates to a new and novel means for retaining water in a pump chambar and more particularly to a pump impeller in a pump casing with a shaft to rotate the pump impeller and a sealing means between the pump impeller and pump casing or bearing to prevent leakage from the pump chamber to the exterior.

In the use of washing machines, a pump mechanism having an inlet and outlet attaches to the main washing tub of the washing machine, in an outlet line leading from the tub, to rapidly drain the washing machine of water. The pump mechanism of the type herein described has an impeller of rubber or other resilient material. If a hard object such as buttons, buckles, etc. enters the pump chamber, the rubber vanes of the impeller being distortable pass over the hard object without injury to the pump impeller. In passing over any hard objects, the impeller exerts a drag or pull on the hard object to move it to the pump outlet without stopping the pump action and consequently without halting the draining of the washing machine tub.

Objects of the invention are to provide: a new seal between an impeller in a pump chamber and a shaft to rotate the impeller attached thereto with relation to a pump casing; a new sealing means for pump impellers which eliminates the use of stuffing boxes, packing glands or similar means for containing water in a pump chamber; a new combination impeller and seal arrangement whereby high sealing pressures are provided when the pump is not in use, which is the large percentage of the time, and the pressure on the sealing means relieved by centrifugal force when the impeller is rotated at high speed to thus insure a minimum wear on the sealing means during operation of the pump; a sealing means for pumps that is simple in construction, durable and economical; and a shaft sealing arrangement whereby an impeller shaft of ordinary material may be employed without concern for non-corrosive qualities.

The invention includes the provision of an impeller carried on a shaft for operation within the pump casing. The shaft extends through an inwardly projecting portion of the casing which forms a bearing for the shaft. The improvement in the present invention consists of a sealing means between the impeller and the bearing portion of the casing to seal the space therebetween and about the impeller shaft. The sealing means may be attached to the impeller or formed as an integral part thereof in the form of an extension of the impeller. The impeller extension is preferably thinned or feathered so that by making the inner diameter thereof smaller than the bearing portion it may be stretched to fit snugly thereover and thereby maintain a satisfactory seal. This sealing engagement with the bearing portion may thus be effected by either tension of the rubber extension stretched thereover or biased by spring pressure or pressure of fluid from the tub or both. A can or sleeve member may be placed over the end or sides of the bearing portion to insure a smooth contacting surface for the impeller extension during rotation. A metallic bushing may be embedded in the impeller to attach the shaft to the impeller, or the shaft may be molded in the impeller material. Where the shaft is molded in the impeller with the seal of m present invention, a shaft may be selected for economic reasons without concern whether or not the shaft material has non-corrosive qualities.

With the foregoing and other objects in view, the invention will be more fully described hereinafter and will be particularly pointed out in the claims appended hereto.

In the drawings:

Figure 1 is a plan view of the pump with part of the cover broken away to show the impeller.

Figure 2 is a sectional View through the pump casing showing one species of sealing means between the impeller and bearing portion;

Figure 3 is a view in perspective of the rubber impeller;

Figure 4 is a part sectional view of the pump and, another form of sealing means; and

Figures 5 and 6 are part sectional views of the pump showing still further forms of sealing means.

Figure 1 shows a pump generally represented at l includes a casing 2 having an inlet 3 and an outlet i. The casing 2 has a cover plate 5 with spring latches 6 engageable with lugs 1.

An impeller 8, made of rubber or other resilient material, and having one, two or more blades, is rotatably mounted in the casing 2. A shaft 9 is rigidly connected, preferably by insert molding, to the impeller 8 at one end thereof while the other end connects with a source of motive power (not shown). The casing 2 has an inwardly extending portion ill which forms a bearing for the shaft 9. In Figure 2 a bearing member I I is included between the shaft 9 and bearing portion ill of the casing.

The improvement in the present invention resides in sealing the space between the pump chamber within casing 2 and the shaft 9. In

3 the figure 2, the bearing portion ID has a cap or sleeve member I2 preferably of a material such as a hard wearing plastic or stainless steel. The impeller 8 has an annular extension 13 extending outwardly to form a socket for receiving shaft 9.

A thrust bearing [4 is disposed at the bottom of the socket for contact with cap l2. As can readily be seen, extension I3 is feathered and fits snugly around bearing portion It to seal the space between bearing portion and the impeller 8. When the impeller 8 is not rotating during the normal wash period, water from the wash tub fills inlet 3 under a static head. In this condition the feathered rubber lip or extension I3 is forced into sealing engagement with bearing portion l2 mainly due to the tension set up in stretching the rubber lip over the bearing portion. During the drain period, the pump impeller 8 is rotated and the centrifugal force induced by this rotation lessens the sealing pressure of the feathered rubber lip on the bearing portion 12, thus greatly reducing wear of the sealing surfaces. A good tight seal is maintained when the inlet 3 is under static head and the pump is not operating, which is the majority of the time, and when the pump is operating a lighter seal pressure is realized which greatly reduces heat which would be generated under the much higher pressure.

In the species of Figure 4, the bearing portion [5 has a cap member i6 thereon, and the impeller I! has an integral feathered extension i8 similarly as described for Figure 1 which seals with cap member 16 on the end of bearing portion IS. A coil spring I9 is placed around extension [8 to force or distort the resilient extension into sealing engagement with the bearing portion 15. A second extension 2'51 integral with impeller ll extends from the outer edge of the impeller to provide a cover for coil spring 19. A metallic bushing 21 is embedded in impeller I1 and shaft 9 is rigidly attached thereto. A flat spring member 22 is placed between bushing 2| and cap 16 to serve as a wear plate due to relative rotary motion between the two members.

Figure 5 is another embodiment similar in many respects to the embodiment shown in Figure 4. The extension 23, in this embodiment, extends coaxially of the impeller 24 and is adapted to overlie the cylindrical surface of bearing member 25 supported by portion 2E5 of the casing. To ensure adequate sealing pressure, a coil spring 21 is placed over the extension 23.

Figure 6 shows a further variation wherein the bearing portion of the casing is provided with an annular abutment 29 capped over with a sheet of metal 30 such as stainless steel. The impeller is provided with an annular extension 3i adapted to engage and form a seal with the metal cap 30. To ensure adequate engagement, a spring 32 is placed on the shaft 9 between bearing 34 and an abutment 35 keyed to the shaft. The spring 32 urges the shaft in a direction to force the extension 3i against the metal surface 30.

While the invention has been described in connection with several specific embodiments, it is to be understood that the words which have been used are words of description rather than of limitation, and that practice of the invention within the scope of the appended claims may be resorted to without departing from the true scope ofthe invention in all its aspects.

I claim:

1. In a pump structure, the combination comprising: a pump having a housing, a rotary resilient pumping element of deformable material cooperating with the internal walls of the housing, bushing means in said housing, said bushing means having a circular projection extending into said resilient pump element and encircled by said element to deform said material radially outward and to thereby be resiliently engaged.

2. A pump having in combination, a casing including inlet and outlet ports, a shaft disposed within said casing and rotatably mounted in respect thereto, an impeller of resilient material including an annular lip portion encircling said shaft, a bearing element interposed between said shaft and said lip portion, said lip portion being inherently biased for fluid sealing engagement with said bearing element during impeller actuated fluid fiow through said casing and adapted to more firmly engage said bearing element upon static hydraulic pressure built-up within said casmg.

3. A pump having in combination, a casing including inlet and outlet ports, a shaft partially disposed within said casing and rotatably mounted in respect thereto, an impeller of resilient material including an annular lip portion encircling said shaft, a bearing element interposed between said shaft and said lip portion, said lip portion being inherently biased for fluid sealing engagement with said bearing element during impeller actuated fiuid flow through said casing and adapted to more firmly engage said bearing element upon static hydraulic pressure build-up within said casing.

4. The pump of claim 3 wherein the sealing surface of said bearing element comprises a metal offering high resistance to wear due to rotation of said resilient impeller lip portion in respect thereto.

5. The pump of claim 3 wherein a bearing sleeve is interposed between said bearing element and said lip portion.

6. A pump structure including a casing provided with inlet and outlet ports and a shaft receiving aperture, a drive shaft extending through said aperture to the interior of said casing, means journaling said driving shaft in respect to said casing, said means including a packing member fixed to said casing and a bearing sleeve snugly engaged between said member and said shaft and including a portion extending into said casing beyond said packing member, an impeller of resilient material fixedly mounted on said shaft within said casing for rotation therewith and including a hub portion provided with an axially extending annular skirt-like integral extension receivable about said sleeve element and inherently biased for light contractile engage ment with the surface thereof, said skirt-like impeller portion being adapted to sealingly engage said sleeve as the result of said inherent contractile biasing during periods of fluid fiow through said casing rotation of said impeller and to engage said sleeve under substantially increased pressure during periods of non-rotation of said impeller due to inwardly directed pressure thereon resulting from increased static pressure build-up of fluid within said casing during said latter periods.

MORTON A. KREITCHMAN.

(References on following page) 5 References Cited in the file of this patent Number 2,436,996 UNITED STATES PATENTS 2,439,315 Number Name Date 2 4 0 952 1,764,706 Willi J111'16 17, 1930 5 2 592 91 2,021,346 Allen Nov. 19, 1935 2,027,505 Winkler Jan. 14, 1936 2,245,866 McLachlan June 17, 1941 Number 2,258,371 Wernert Oct. 7, 1941 497,287 2,408,909 Brummer Oct. 8, 1946 10 Name Date Howser Mar. 2, 1948 Newton et a1 Apr. 6, 1948 Simer et a1. Feb. 8, 1949 Atkins et a1 Apr. 4, 1950 FOREIGN PATENTS Country Date Great Britain Dec. 16, 1937

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