US2734460A

US2734460A - Primer for centrifugal pump

Info

Publication number: US2734460A
Authority: US
Publication date: 1956-02-14
Anticipated expiration: 1973-02-14

Description

Feb. 14, 1956 DETERS ET AL 2,734,460

PRIMER FOR CENTRIFUGAL PUMP Filed Nov. 1, 1951 I Irv anionsan, m. Adah,

United States Patent PRIMER FOR CENTRIFUGAL PUMP Elmer M. Deters and Glenn A. Patterson, Davenport, Iowa, assignors to Red Jacket Manufacturing Company, Davenport, Iowa, a corporation of Iowa Application November 1, 1951, Serial No. 254,312

4 Claims. (Cl. 103-113) This invention relates to a primer for a centrifugal pump, and in particular to a priming attachment for a shallow well centrifugal pump. 7

It is an object of this invention to provide a novel arrangement for rendering a centrifugal pump self-priming in its operation. 3

Another object of this invention is to .provide a centrifugal well pump in which only the pump itself need be primed initially, without the necessity of also priming the suction pipe leading to the pump from the well.

Another object of this invention is to provide for the automatic re-priming of a centrifugal'pump in case air enters the suction inlet thereto during its operation.

Yet another object of this invention is to provide for the automatic recirculation of water to the suction inlet of a centrifugal pump in the event that air is drawn thereinto, so as to force the air through the impeller of the pump and insure the continued operation of the. pump.

A further object of this invention is to provide for the re-priming of a centrifugal pump automatically responsive to the internal pressure in the pump;

Other and further objects and advantages of the invention will be apparent from the following description of a preferred embodiment, herein shown to illustrate the principles of the invention.

In the drawing: a

Figure 1 is a view showing in longitudinal section the operating parts of the centrifugal pump and .the selfpriming mechanism therefor, and I Figure 2 is a fragmentary exploded perspective view illustrating the manner in which the priming attachment of the present invention may be attached to the centrifugal pump. 7

Referring to the drawings, the numeral 10 illustrates an electric motor which serves as the prime mover for the centrifugal pump 11. The rotary pump shaft 12 is suitably connected to the motor shaft 13 to be driven thereby. The pump shaft has a reduced diameter segment 12a which extends through the housing wall 14 and is provided with a suitable bearing and fluid seal thereat, indicated generally at 15, which prevents leakage of fluid from the impeller pump chamber 16. A hearing bushing 17, which is mounted in the inlet or'suction passageway 18 to the pump, forms a bearing for the impeller 19, which is mounted on the free end of the pump shaft 12a. A compression coil spring 20 urges the seal member a, which rotates with the pump shaft, against the stationary seal and bearing member 15.

The impeller includes an annular forward nose 21 which extends within the bearing bushing 17 and which defines an axial inlet passage or eye 22 which communicates with the suction passage 18 in the pump to draw water therethrough. A plurality of centrifugal discharge passages 23 extend outward from the eye 22 of the impeller for discharging the water by centrifugal force when the impeller is rotated. An annular discharge chamber 24 is formed in the pump housing to extend completely 2,734,460 Patented Feb. 14, 1956 around the impeller chamber 16 and communicates with the impeller discharge passages 23 for receiving the water discharged therefrom. At the top of the pump discharge chamber 24, an outlet fitting 25 is attached which provides an outlet for the pump.

The pump housing 11 is also formed with a recirculation passage 26 which communicates with the lower end of the discharge chamber 24 in the pump and terminates in a port 27 located below the inlet to the suction passage 18 in the pump.

In accordance with the present invention there is provided a priming attachment, indicated generally at 40, releasably attached to the front face of the pump housing and provided with an inlet passage 28, which is positioned to register with the suction passage 18 in the pump, and a recirculating passage 29, which is positioned to register with the port 27 in the front face of the pump housing. A gasket separates the abutting faces of the pump housing and the priming attachment.

A transverse primer passage 31 extends between the passages 28 and 29 in the priming attachment and is provided at its lower end with an annular valve seat 32. A reciprocable primer valve 33 is mounted on a stem 34 which is attached to a resilient diaphragm 35. The coil spring 36 engages the rear of the diaphragm and tends to urge the latter to a position where the primer valve 33 is unseated to establish communication through the primer passage 31 between the pump discharge chamber 24 and the suction passage 18 in the pump. The water pressure in the priming attachment passage 29 opposes this action of the spring 36, and when the pump is operating to establish a normal water pressure in the discharge chamber 24 this water pressure will overcome the spring bias on the diaphragm 35 and will maintain the latter retracted to seat the primer valve 33 against its seat 34 i and block communication between the pump discharge chamber 24 and the suction passage 18 in the pump.

The inlet passage 28 in the priming attachment is located at the bottom of a chamber 37 having a check valve at its upper end. The check valve is of the flapper type having a flexible closure member 38 of leather or the like and an attached weight 39 which biases the flapper to close the inlet port 41 to the chamber 37 in the priming attachment. The suction pipe 42 from the well communicates with this inlet port for discharging water into the chamber 37 in the priming attachment. The chamber 37 provides a water trap for maintaining the impeller 19 submerged at all times.

In the operation of the pump, initially the pump is primed by filling the pump casing with water through the discharge opening at the top of the discharge chamber 24. This submerges the impeller and also provides an initial volume of water in the trap chamber 37 at the suction side of the pump. After this initial priming of the pump, the pump will thereafter re-prime itself automatically when necessary. To set the pump in operation, it is not necessary to also prime the suction pipe 42 leading from the well. The pump will begin operating and continue to operate even though the suction pipe 42 is full of air, as will be apparent hereinafter.

When the motor 10 is energized to rotate the impeller 19 the water in the trap chamber 37 and the suction passage 18 is drawn into the impeller, thus creating a partial vacuum at the chamber 37. The check valve 38 then opens and air from the pipe 42 leading from the well is drawn into the impeller. At this time the water pressure against the diaphragm 35 is insufficient to overcome the bias of the spring 36, so that the primer valve 33 is maintained open and water is recirculated from the pump discharge chamber 24 through the primer passage 31 into the suction passage 18 in the pump leading to the eye of the impeller. Thus, as gulps of air from the pipe 42 are drawn through the suction passageway 18 in the pump they are forced through the impeller by the stream of recirculated water from the primer passage 31. The air after being discharged from the impeller passes out through the discharge outlet at the top of the pump discharge chamber 24. The water at the bottom of this chamber is relatively air free.

After a time water is drawn through the pipe 42 into the suction passage 18 in the pump and is discharged from the impeller into the pump discharge chamber 24. The pump thus having attained its prime, the water pressure in the pump discharge chamber 24 builds up and overcomes the spring bias on the diaphragm 35 to close the primer valve 33 and shut off the stream of recirculated water.

Thereafter, whenever an excessive amount of air is drawn into the pump the pressure in the pump discharge chamber 24 will drop and permit the primer valve 33 to open for recirculating water through the primer passage 31 to force the air through the impeller and automatically re-prime the pump.

While in the foregoing description there is disclosed a specific preferred form of the present invention, it is to be understood that various changes and modifications departing from the described form of the invention may be adopted which do not depart from the spirit and scope of our invention.

We claim:

1. In combination with a centrifugal pump having a suction inlet and a recirculating passage communicating with the discharge chamber in the pump and a ported face at which said suction inlet and recirculation passage terminate, a priming attachment having a ported face attached to the pump with the ported face of the attachment confronting the ported face of the pump, said attachment being formed with an inlet passa e terminating at the ported face of the attachment and positioned thereat in communication with said suction inlet for the pump, a recirculation passage leading from said ported face of the attachment and positioned thereat in communication with said recirculation passage in the pump, a primer passage communicating between said inlet and said recirculation passages in the attachment, and a normally open valve in said primer passage movable in response to the pressure in said recirculation passage in the attachment to close when the fluid pressure in the recirculation passage in the attachment exceeds a predetermined value and to recirculate fluid from the recirculation passage in the attachment to said inlet passage in the attachment when the pressure in the recirculation passage in the attachment drops below a predetermined value.

2. in combination with a centrifugal pump which has a suction inlet and a discharge chamber communicating respectively with ports at a fiat planar ported face of the pump, a priming attachment including a casing having a fiat ported face for attachment to the pump at the ported face thereof with the respective ports at the ported face of the attachment casing registering with the ports at the ported face of the pump, said attachment casing enclosing an inlet passage terminating in a port at said ported face of the attachment casing positioned in registry with said suction inlet for the pump, a recirculation passage terminating in a port at said ported face of the attachment casing positioned in communication with said discharge chamber in the pump, a primer passage effecting cornmunication between said recirculation and inlet passages in the attachment, and a normally open valve in said primer passage operative to close in response to a predetermined pressure in said recirculation passage for recirculating liquid from said recirculation passage to said inlet passage.

3. In combination with a centrifugal pump which has a suction inlet and a discharge chamber terminating in ports at a ported front face of the pump, a priming attachment comprising a casing having a ported face attached to the pump with the ported face of the attachment positioned in confronting relation with the ported front face of the ptunp, means in said casing defining an inlet passage terminating in a port at said ported face of the attachment casing positioned in registry with the suction inlet of the pump, means in said attachment casing defining a recirculation passage disposed below said inlet passage and terminating in a port at said ported face of the attachment casing positioned in communication with the discharge chamber port in the front face of the pump, means defining a primer passage in said attachment casing effecting communication between said recirculation and inlet passages in the attachment casing, a valve in said primer passage, and pressure responsive means communicating with said recirculation passage and controlling the position of said valve, said pressure responsive means being operative to maintain the valve closed when normal pressure is maintained in said recirculation passage and operative in response to a drop in pressure in said recirculation passage to open the valve for recirculating liquid from said recirculation passage to open the valve for recirculating liquid from said recirculation passage to said inlet passage in the attachment.

4. The combination of claim 3, wherein there is provided an annular valve seat in said primer passage, and a stem interconnecting said valve and said pressure responsive means, the walls of said primer passage being spaced from said valve stem to define an annular flow path around the stem and said stem extending loosely through said annular valve seat and spaced therefrom in all positions of the valve stem, and said valve being located at the side of said valve seat remote from said pressure responsive means to abut against said valve seat in one position of the stem and to be unseated therefrom in other positions of the stem.

References Cited in the file of this patent UNITED STATES PATENTS