US2281175A - Priming means for self-priming pumps - Google Patents

Description

April 28 1942. A. c. STRATTON I 2,281,175

PRIMING MEANS FOR SELF-PRIMING PUMPS Filed 001.. 4, 1940 INVENTO R I m/Am ATTORNEY Patented Apr. 28, 1942 PRIMING MEANS FOR. SELF-PRIMING PUMPS Albert C. Stratton, Ridgewood, N. .L, assignor to Alfred S. Marlow, Ridgewood, N. J.

Application October 4, 1940, Serial No. 359,662

4 Claims.

My invention relates to improvements in a priming means for self-priming pumps. It relates more particularly to the means for the construction of self-priming centrifugal pumps wherein the operation of the pump impeller with residual liquid is adapted to cause the pump to prime itself and subsequently discharge its full capacity without the employment of mechanical devices.

Centrifugal pumps may be broadly divided into two types, volute and turbine. In my application bearing Serial Number 253,540, I disclose a self-priming pump construction of the volute type. This present invention provides a new and novel construction of a self-priming pump employing the turbine type with a consequent simplification of parts and a resulting improvement in pump performance,

The following objects are accomplished by my invention. The first is that the device herein disclosed, by avoiding the use of the volute, makes possible a lower cost of construction of a centrifugal self-priming pump. It is recognized in the art that one of the principal elements of cost in a .centrifugal pump is the volute casing enclosing the impeller. A second is that the construction herein disclosed permits the use of smaller pump cases than is possible with the conventional volute type of self-priming centrifugal pumps. A third is that the pump parts and cases are symmetrical. A fourth is that greater ability to exhaust air is obtained. Multiple mixing ports together with a short fluid travel from impeller to reserve tank accomplish a very high air capacity. A fifth is that the pump impeller is more effectively sealed, thus making it possible to develop a more perfect vacuum within the pump suction.

Turbine type pumps, having a series of diffusion vanes and passages for directing the liquid away from the impeller; are well known to the art; that type being preferred for pumps having more than one stage. My invention embodies, among other things, this well known principal of diffusion vanes in a construction and method of use which will make the pump of my invention completely self-priming and suitable for either single or multi-stage.

My invention applies to all types of suction pumps of the centrifugal or impeller type and may supplant the present pumps of said types. It is also applicable to the class of pumps known as "construction pumps as covered by my former inventions #2,059,288 and #2,100,365. Said latter class of pumps call for a high capacity performance, self-priming dependability, and light weight for portability.

One form of my invention is illustrated in the accompanying drawing in which Figure 1 shows a front elevation partially cross-sectioned taken on line l-l of Figure 2. Figure 2 is a crosssectional view through the pump.

Reading on Figures 1 and 2 of my drawing, they consist of main housing 23, and cover plate 2|, having a suction connection 20 and a suction chamber l9. Impeller l0 having vanes II, is supported and driven by shaft l2, having bearing member l3, contained in rear extension'29; having stufling box I4, bearing extension I5 and ball bearings l6, and is enclosed by fixed diffusion disc l1 which is provided with suction passage I8 connecting with said suction chamber I9 and said suction connection 20 in cover plate 2|. Combination check valve and gasket 22 is used to seal the suction passage where cover plate 2| and difiusion disc l1 meet and covers valve opening 22a.

Diifusion disc l1 and impeller ID are completely enclosed by main housing 23 and cover plate 2|, so that liquid placed within main housing 23 will submerge difiusion disc l1 and impeller I0. A flange 30 forms part of rear housing extension 29 and serves to position the stationary vanes 26 of diffusion disc 11. A suitable discharge connection 24, is provided having a removable plug 25, which may be removed to permit filling the main housing 23 with liquid. Diffusion disc 11 is further provided with vanes 26, ports 28, and passages 21, evenly spaced about the rotating impeller. The vanes 26 and passages 21 between the vanes can be made to conform to the design known in the art as diifusion vanes; their purpose being to direct the liquid away from the impeller l0, and cause a transition from velocity head to pressure head within passages 21. It will be noted that passages 21 communicate directly with the impeller periphery at their inner and smaller end and open into the interior of main housing 23 at their outer and'larger ends. Thus when main housing 23 is filled with liquid, this liquid also enters and fills passages 21 of diffusion disc [1. When impeller I0 is not rotating the liquid within main housing 23 will flow through the diffusion vane passages 21 and fill all fiuid openings in impeller l0, and the suction passage l8. Check valve 22 prevents the liquid from being siphoned into the suction pipe when the pump is shut down, thus retaining priming liquid within the pump during shut down periods.

In operation, reading on Figures 1 and 2 the main housing 23, and all the interior passages within said housing are filled with the liquid through opening at removable plug 25. When impeller I is made to revolve in the designated direction as shown by arrow Illa, centrifugal force exhausts the liquid from impeller passages I la forming simultaneously a difference in pressure between the empty impeller passages Ila and the liquid filled diffusion passages 21. Because of this difference in, pressure the liquid in passages 21 and ports 28 flows against the periphery of impeller Ill and due to impact with the rotating impeller, is broken into a mechanical mixture of air and liquid having greater volume than the liquid alone. This mechanical mixture, partly because of its increased volume and partly due to the centrifugal force from impeller I0, is caused to flow out of passages 21 into the interior of main housing 23, where the air and liquid separate due to a reduced velocity of flow. Thus by this process air is removed from vane passages Ila, suction inlet I8 and suction chamber I9 and any suction hose or piping that may be connected to the pump section 20, and is subsequently discharged from the residual liquid in main housing 23 through the top discharge connection 24. This process continues until sufficient vacuum is formed to lift the liquid to the pump thus completing the priming operation. During this priming operation ports 28 in diilusion disc I! direct a flow of residual liquid comparatively free from air, directly to the pcriphery of the impeller I0 and establishes a recirculating flow through ports 28, passages 21 and the casing interior. When all air is exhausted and the pump primed, the entire pump interior, including passages 21, impeller passages Ila and suction passage I8, will be entirely filled with liquid, forming a continuous unimpeded flow of liquid through the pump interior. It will be noted that under this invention all of the advantages and high pump efficiency of the turbine pump are retained. The water passages are all direct, as short as possible, and unobstructed by automatic devices.

While I have illustrated my invention in different ways and using different materials and means, still I do not intend to limit myself to those particular means, designs, methods or materials, as it is apparent that other means, designs, methods, and materials may be employed for obtaining the same results within the scope of any claim without departing from the scope or spirit of my invention:

I claim:

1. A self-priming pump of the turbine type as herein described, comprising in combination a case holding reserve liquid and having a suction inlet and discharge outlet, 9. propelling unit'submerged within said reserve liquid consisting of a rotating impeller enclosed on one face by a disc having at its center a suction opening in communication with said suction inlet and at its periphery a series of conventional diffusion passages in radial alignment with said impeller leading forward in the direction of the impeller rotation only enough to overlap an adjacent passage, each passage opening directly into said re serve liquid, and admitting said reserve liquid to the impeller periphery for agitation into an air liquid mixture, said enclosing disc provided with small port holes communicating between said reserve liquid and said diffusion passage at the periphery of said impeller to accelerate the outward flow of said air-liquid mixture from said diffusion passage into said reserve liquid.

2. A self-priming pump of the turbine type as herein described; comprising a casing holding reserve liquid and having a section inlet and discharge outlet, within said casing a diffusion disc having at its center a suction passage in communication with said suction inlet, and having about its periphery one or more diffusion vanes with intermediate liquid passages, within said diffusion disc a rotating impeller having vanes facing said diffusion disc and extending from the said suction passage to the inner periphery of said diffusion vanes, port holes through said diffusion disc located immediately outside the path of said impeller and directly forward the inner tip of each diffusion vane for the admission of air free reserve liquid from the side of said diffusion disc to the periphery of said impeller, said diffusion vane passages leading forward in relation to the rotation of said impeller and opening into said casing at substantially equidistant points about the periphery of said diffusion disc.

3. A self-priming pump of the turbine type, as herein described, comprising in combination a case holding reserve liquid and having a suction inlet and discharge outlet, a propelling unit submerged within said reserve liquid consisting of a rotating impeller enclosed on one face by a disc having at its center a suction opening in communication with said suction inlet and at its periphery at least four diffusion vanes with intermediate liquid passages of similar contour and in radial alignment with said impeller and leading forward in the direction of the impeller rotation, port holes through said diffusion disc located directly forward the inner tip of each diffusion vane for the admission of air free reserve liquid from the side of said diffusion disc to the periphery of said impeller, and outside the periphery of said impeller, said diffusion vane passages opening abruptly into said casing at substantially equidistant points about the periphery of said diffusion disc.

4. A self-priming pump of the turbine type, as herein described, comprising in combination a. case holding reserve liquid and having a suction inlet and discharge outlet, a propelling unit submerged within said reserve liquid consisting of a rotating impeller enclosed on one face by a disc having at its center a suction opening in communication with said suction inlet and at its periphery multiple diffusion passages alike in contour and in radial alignment with said impeller and leading forward in the direction of the impeller rotation, to direct a like number of radial streams of liquid into said reserve liquid tank when pumping, and to remain filled with said reserve liquid for agitation by said impeller when priming, said disc provided with ports located adjacent to but outside the path of said impeller, said ports directing a small flow of air-free reserve liquid into said discharge outlets at the impeller periphery to accelerate the flow of aerated liquid from said passages into said reserve liquid.

ALBERT C. STRATTON.

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