US3082694A - Self-priming centrifugal pump - Google Patents

Description

M 1963 A. BRKICH 3,082,694

SELF-PRIMING CENTRIFUGAL PUMP Filed May 24, 1960 2 Sheets-Sheet 2 INVENTOR ALEXANDER BRk/Ch United States Patent Ofi ice 3,082,694 Patented Mar. 26, 1963 3,082,694 SELF-PRIMING CENTRIFUGAL PUMP Alexander Brkich, Phillipsburg, NJ assignor to Ingersoll- Rand Company, New York, N.Y., a corporation of New Jersey Filed May 24, 1960, Ser. No. 31,378 3 Claims. (Cl. 103-413) This invention relates to centrifugal pumps and particularly to that type of pump which will be self-priming.

For certain uses of pumps, such as in sumps or in locations where the water or the fluid pumped is dirty, it is impractical to use pump elements such as reciprocating pistons, vanes and the like which will be affected by sand or other gritty material, although their use and general character makes them inherently self-priming. The conditions described necessitate the use of pumps in which there is practically no rubbing surface provided. For this purpose, the centrifugal type of pump is ideal, but in starting it must either be submerged or primed as it will ordinarily not pump air.

This invention contemplates the use of an auxiliary priming pump to remove air from a centrifugal pump suction, the priming pump being of the well-known water ring type in which a rotating ring of water in an eccentrically disposed chamber has a piston-like action producing suction for pumping either air or water.

The invention contemplates, also, a unitary structure combining the two types of pumps operating simultaneously. This arrangement presents a problem of maintaining, under all conditions, the water-ring pump primed for starting purposes, and in furtherance of this as a solution of this problem, means is provided to insure that the priming pump is not drained when the apparatus comes to rest.

It is accordingly an object of the invention to provide an improved form of pump which is reliable and selfpriming under all conditions.

It is a further object of the invention to insure that the priming element will remain, itself, primed.

These and other objects and the advantages thereof will be in part obvious and in part pointed out hereinafter.

In the drawing is illustrated an improved embodiment of the invention, in which FIGURE 1 is a longitudinal section of a pump constructed in accordance with the practice of the invention, and

FIG. 2 is a cross section at line 22, looking in the direction of the arrows.

Within a volute type casing is mounted a main centrifugal type rotor 12 having a drive she-ft 14 which may be the drive shaft also of the driving motor 16. Casing 10 has a detachable inlet nozzle 18 forming an inlet passage 20 to the casing 10. In addition, casing 10 is provided with a discharge passage 22 in the discharge nozzle 24 formed integrally with casing 10. Discharge passage 22 communicates With a suitable discharge conduit 26, there being interposed at the entrance to conduit 26 a check valve assembly 28 which, in this instance, comprises a screwed-in insert or seat 30 with which a valve member 32 cooperates to check the flow of liquid or air in the reverse direction from the conduit 26 to the casing 10.

Valve member 32 is held resiliently to its seat 30 by a spring 34 held in place by stop member 36 mounted on the central stem 38.

The parts so far described are rather conventional in character. It will be understood that the rotor or impeller 12 is adapted to pick up liquid from the inlet passage 20 and to discharge it at discharge passage 22 and past check valve 28 into the discharge conduit 26.

Pumps of this type are often used for intermittent service. If the pumps stand idle for any substantial time, liquid drains out since check valves 28 are somewhat leaky; and, in any case, when initially starting up, they have to be primed, as an impeller such as that shown at 12 is not at all effective as an air pump.

Accordingly, this pump is provided with a built-in priming means which, in this instance, includes a pump of small capacity which is adapted to pump not only liquid but gas as well. Preferably, this pump is of the so-called water ring type which has a housing 40 of generally cylindrical section having an end wall 42 integrally formed with housing 40 and a second end wall 44 substantially parallel thereto. Housing 40 is eccentrically disposed with respect to drive shaft 14 which passes through housing 40 and supports a radially vaned impeller 46 keyed thereto. Housing '40 is provided with an inlet port 48 in wall 42 and a discharge port 50 in Wall 44.

Pump housing 40 is enclosed in a laterally extending circular flange 52 formed integrally with casing 10 having a head 54 to enclose a cavity 56 of considerable volume which, as will be described later, is adapted to contain priming liquid in substantial quantity. Cavity 56 also acts as a supply and discharge chamber for the water ring pump. Head 54 also acts as a means of securing housing 40 in place and holding its parts together. Pulling up on the ring of securing bolts, of which one is shown at 58, forces Wall 44 into contact with the main part of housing '40 and also pushes wall 42 against a central protrusion 60 at the back of casing 10 as shown at 62. A tight seal between the head 54 and flange 52 is provided by an O-ring 64. A further seal is provided in the stuffing box portion 66 of head end 54 which is adapted to contain sealing material 68 cooperating with a gland 70 on shaft 14, and resiliently compressed by spring 72 hearing against a washer 74 abutting a collar 76 on shaft 14, which collar is secured in place by a suitable set screw 78. Any leakage that may occur at the stuffing box 66 is prevented from entering motor 16 by a ilinger 80.

As has been before indicated, the water ring pump is of small capacity as compared with the main pump and its purpose is to evacuate the space with which inlet passage 2% is associated. To this end, that portion of the cavity 56 adjacent inlet port 48 communicates with inlet passage 20 by a pipe 81 connected at a threaded hole 82 in nozzle 18 at one of its ends and at the other end threaded into a bore 84 in the upper side of cavity 56.

Housing 40 is cut away as at 85 to provide free communication with cavity 56. The discharge of the priming pump is conducted into discharge conduit 26 by pipe 86 connected to discharge conduit 26 and a hole 88. The other end of pipe 86 connects with that portion of cavity 56 adjacent discharge port 50 at a hole 91 in the top side of head 54.

The principle of operation of the priming pump of which the elements have been described is well understood in the art, which is variously known as a waterring pump, or wet-vacuum pump. and 'by various other names.

Its general principle is as follows: Liquid entering inlet port 48 is caused to rotate by the radial vanes of impeller 46 as a sort of ring which, because of the eccentricity of the axis of the impeller, will be of varying thickness if the chamber is running full, or, if it runs only part full, the ring of water entrained by the impeller recedes from the center of rotation to cause a vacuum at the inlet port, and then, because of the eccentricity, the ring is caused to approach the center. Air trapped between the vanes of impeller 46 will thus be compressed and squeezed out at discharge port 50. Thus rotation of impeller 46 causes a constant intake of fluid, whether it be gas or liquid, at inlet port 48 and a corresponding discharge at port 50. As motor 16 rotates the rotor 12 and the impeller 46 and as long as there may be water in cavity 56 to prime the priming pump, that is to say, to enter port 48, a suction will be formed to draw gas through hole 82 at inlet passage 24) and to discharge the same through pipe 86 into discharge conduit 26. Also, if inlet passage is running full of liquid, pipe 81 will conduct liquid to the priming pump which in a small way will add to the discharge of the assembly.

When the pump is stopped, discharge conduit 26 will tend to evacuate, assuming that it is discharging into atmospheric conditions, and liquid will pass by way of pipe 86 into cavity 56 and thence by way of pipe 81 back into the inlet passage 20. It is desired, however, that the priming pump should be in condition to evacuate air from inlet 20 upon restarting. To this end, cavity 56 is adapted to retain a quantity of liquid suflicient to prime the priming pump. For this purpose, ports 48 and 50 have portions extending into the upper part of cavity 56 so that when pipe 86 has been emptied, suction in pipe 81 will cease by leakage from the top of port 50 to the top of inlet port 48 without withdrawing liquid below these points to any substantial extent. To facilitate this leakage, a groove 90 is cut in the inner wall of the chamber within housing to conduct reverse flow between ports and 48. Groove 90 should not be deep and its effect is to nullify, only to a slight degree, the pumping action of the priming pump by the reverse flow produced. However, there is no loss of liquid for priming, inasmuch as reverse flow merely tends to refill the inlet side of cavity 56.

For mounting motor 16, a bracket 92 is provided with an inwardly turned flange 94 by which it is bolted to casing 10 as at 96 and at a second inwardly turned flange 98 attached, as by bolts 100, to the face of motor 16.

Rotor 12 is balanced as to the front and back pressures acting upon it by the use of wearing rings 162 at a flange 104 extending from the back face of rotor 12. The leakage past the back flange 104 will pass along shaft 14 and into cavity 56 as that part is maintained at suction pressure, the sealing of shaft 14 at the protruding part being imperfect intentionally.

Thus by the above construction are accomplished, among others, the objects hereinbefore referred to.

I claim:

1. A self-priming centrifugal pump assembly comprising a casing, a main rotor mounted in said casing for rotation, rotary power means connected to said main rotor for rotating the latter, said casing having an inlet to receive fluid to be pumped and pass the same to said main rotor and a discharge passageway for receiving pumped fluid from said main rotor, a discharge conduit communicating with said discharge passageway to receive pumped fluid from the latter, a check valve disposed in said discharge conduit to control flow of fluid from said discharge passageway through said discharge conduit, and a priming pump in said casing adapted to handle gas and liquid, said priming pump comprising a cylindrical chamber formed in said casing, a radially bladed rotary impeller eccentrically mounted in said cylindrical chamber with its axis of rotation substantially horizontal, said impeller being connected to said rotary power means for rotation, an inlet means communicating with said cylindrical chamber and said casing inlet to draw fluid from the latter, a discharge means in communication with the chamber and said discharge conduit downstream of said check valve to pass fluid ptunped by said impeller to said discharge conduit, said inlet means and said discharge means being located in communication with said cylindrical chamber partly above the axis of said impeller, and a by-pass groove of small capacity compared with the priming pump capacity formed in the wall of said cylindrical chamber and extending circumferentially at least partly around the upper periphery of said cylindrical chamber for conducting gaseous fluid from the discharge means to the inlet means and thereby inhibit the syphoning of fluid out of the priming pump when the assembly is shut down.

2. A self-priming pump assembly comprising the combination of a centrifugal pump and a priming pump, said centrifugal pump comprising a casing for said centrifugal pump, a rotor mounted in said casing for rotation, rotary power means connected to said rotor to rotate the same, said casing having an inlet to receive fluid to be pumped and a discharge passageway for receiving pumped fluid from said rotor, a discharge conduit communicating with said discharge passageway for receiving pumped fluid from the latter, a check valve disposed in said discharge conduit to control flow of fluid through the discharge passageway and conduit, said priming pump comprising a cylindrical chamber formed in said casing, a. radially bladed rotary impeller eccentrically mounted in said cylindrical chamber with its axis of rotation substantially horizontal, said impeller being connected to said rotary power means for rotation, an inlet means communicating with said cylindrical chamber and said casing inlet to draw fluid from the latter, a discharge means in communication with the chamber and said discharge conduit downstream of said check valve to pass fluid pumped by said impeller to said discharge conduit, said inlet means and said discharge means being located in communication with said cylindrical chamber partly above the axis of said impeller, a by-pass groove formed in the inner peripheral surface of said cylindrical chamber and extending circumferentially at least partly around the upper peripheral surface of said cylindrical chamber for conducting gaseous fluid from the discharge means to the inlet means and thereby inhibit the syphoning of fluid out of the priming pump when the assembly is shut down. I

3. A self-priming centrifugal pump assembly comprising a casing, a drive shaft journaled for rotation in said casing, a main rotor in said casing connected for rotation to said drive shaft, rotary power means connected to said drive shaft for rotating the drive shaft and said main rotor, said casing having an inlet to receive fluid to be pumped and pass the same to said main rotor and a discharge passageway for receiving pumped fluid from said main rotor, a discharge conduit communicating with said discharge passageway to receive pumped fluid from the latter, a check valve disposed in said discharge conduit to control flow of fluid from said discharge passageway through said discharge conduit, said casing having a substantially circular flange extending laterally therefrom, a head member secured to said flange to define a storage cavity within the casing, a pump housing disposed within said storage cavity constructed and arranged to define a cylindrical chamber, a rotary impeller having radial vanes and eccentrically mounted for rotation within said pump housing, said rotary impeller being connected for rotation to said drive shaft, inlet passage means in communication with the inlet of said casing and the upper portion of said storage cavity to provide flow of fluid from said inlet of said casing to said storage cavity, discharge passage means in communication with the upper portion of said storage cavity and the discharge conduit downstream from the check valve to pass fluid from the storage cavity to said discharge conduit, an inlet port in said pump housing communicating the interior of said pump housing with the storage cavity and said inlet passage means to pass fluid to be pumped into said pump housing, an outlet port in said pump housing communicating with the storage cavity and said discharge passage means to pass pumped fluid from the pump housing into said storage cavity and said discharge passage means, said inlet port and said outlet port being dimensioned and disposed in said pump housing so that portions of both ports communicate with the upper portion of the pump housing and storage cavity, and a by-pass in the form of a groove in the interior peripheral surface of said pump housing and extending at least 5 partially around the upper peripheral surface of said pump housing for conducting gaseous fluid from the discharge passage means through the inlet and outlet ports of the pump housing and the inlet passage means so that the syphoning of fluid out of the priming pump 10 upon shut-down of the assembly is inhibited.

References Cited in the file of this patent UNITED STATES PATENTS Grise Oct. 7,

Compton Feb. 12,

FOREIGN PATENTS Great Britain Aug. 16,

Great Britain Nov. 13,

Germany Mar. 27,

Germany June 13,

Great Britain July 14,

Claims (1)

1. A SELF-PRIMING CENTRIFUGAL PUMP ASSEMBLY COMPRISING A CASING, A MAIN ROTOR MOUNTED IN SAID CASING FOR ROTATION, ROTARY POWER MEANS CONNECTED TO SAID MAIN ROTOR FOR ROTATING THE LATTER, SAID CASING HAVING AN INLET TO RECEIVE FLUID TO BE PUMPED AND PASS THE SAME TO SAID MAIN ROTOR AND A DISCHARGE PASSAGEWAY FOR RECEIVING PUMPED FLUID FROM SAID MAIN ROTOR, A DISCHARGE CONDUIT COMMUNICATING WITH SAID DISCHARGE PASSAGEWAY TO RECEIVE PUMPED FLUID FROM THE LATTER, A CHECK VALVE DISPOSED IN SAID DISCHARGE CONDUIT TO CONTROL FLOW OF FLUID FROM SAID DISCHARGE PASSAGEWAY THROUGH SAID DISCHARGE CONDUIT, AND A PRIMING PUMP IN SAID CASING ADAPTED TO HANDLE GAS AND LIQUID, SAID PRIMING PUMP COMPRISING A CYLINDRICAL CHAMBER FORMED IN SAID CASING, A RADIALLY BLADED ROTARY IMPELLER ECCENTRICALLY MOUNTED IN SAID CYLINDRICAL CHAMBER WITH ITS AXIS OF ROTATION SUBSTANTIALLY HORIZONTAL, SAID IMPELLER BEING CONNECTED TO SAID ROTARY POWER MEANS FOR ROTATION, AN INLET MEANS COMMUNICATING WITH SAID CYLINDRICAL CHAMBER AND SAID CASING

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