US2520880A

US2520880A - Centrifugal pump

Info

Publication number: US2520880A
Application number: US620780A
Authority: US
Inventors: Anatol J Harlamoff
Original assignee: AO Smith Corp
Current assignee: AO Smith Corp
Priority date: 1945-10-06
Filing date: 1945-10-06
Publication date: 1950-08-29
Anticipated expiration: 1967-08-29

Description

Aug. 29, 1950 A. J. HARLAMOFF 2,520,830

CENTRIFUGAL PUMP Filed Oct. 6, 1945 s Sheets-She et 1 INVENTOR Jlna 3 Sheets-Sheet 2 2 min] J 30%;???

BY flaw,

A. J. HARLAMOFF CENTRIFUGAL PUMP Aug. 29, 1950 Filed Oct. 6, 1945 ATTORNEY Aug. 29, 1950 A. J. HARLAMOFF CENTRIFUGAL PUMP 3 Sheets-Sheet 3 Filed Oct. 6, 1945 ,lnozo'z JAEfiZQZA ATTORNEY Patented Aug. 29, 1950 CENTRIFUGAL PUM'P Anatol J. Harlamofi, South Gate, CaliL, assignor to A. 0. Smith Corporation, Milwaukee, Wis., a

corporation of New York Application October 6, 1945, Serial No. 620,780

This invention relates to a centrifugal pump and is particularly directed to an in-line motorpump unit.

The principal object of the invention is to provide a centrifugal pump with a double volute construction adjacent the impeller that simplifies casting of the pump.

Another object is to provide a simplified construction of a pump that effect increased efficiency. I

A further object is to provide a novel construction for handling the discharge of an impeller of an in-line motor driven pump.

Another object is to provide a plurality of longitudinal ducts around the motor and leading from the volutes to the discharge end of the pump.

In carrying out the invention the diffuser and vanes ordinarily employed in previous constructions are completely eliminated and instead a double volute connects the impeller with a plurality of discharge passages that extend throughout the length of the pump and, around the motor portion of the pump. I

The invention is illustrated in the accompanying drawings, in which:

Figure 1 is a longitudinal central section of a pump illustrating an embodiment of the invention;

Fig. 2 is a transverse section taken on line 2-2 of Figure 1;

Fig. 3 is a transverse section taken on line 3-3 of Figure 1;

Figure 4 is a section broken out of the pump and showing the curvature of one of the volutes and separation thereof into two longitudinal passages; and

Fig. 5 is a section taken on line 5-5 of Figure '1 across the inner end of the discharge nozz e.

The invention is illustrated as employed with a centrifugal pump comprising a generally cylindrical cast housing i with the suction nozzle 2 secured to the forward end thereof and the discharge nozzle 3 secured to the rear end thereof.

The motor 4 is suitably secured within the body portion of the housing 5 in a motor chamber provided by the inwardly extending flange 5 adjacent the forward end of the housing I and the inwardly extending flange 6 adjacent the rear end of housing l.

The forward radial bearings l are secured to web 8 extending inwardly from flange 5 and; the rear radial bearings 9 are secured to flange 6. The shaft Ill of motor 4 i mounted within bearings l and 9 for free rotation thereof by motor 4.

The impeller l I is mounted on the forward end of shaft it within a generally large axial pump chamber formed between the nozzle 2 and the flange 5 of housing i. The impeller ii together with the suction nozzle 2 providing the suction passage to the impeller, the forward wear ring 3 Claims. (01. 103-47) i2, rear wear ring l3, the forward thrust bearing I4, and rear thrust bearing I5 comprise the pump portion of the centrifugal pump described.

The flange 5 extends inwardly substantially to shaft l0 and is sealed thereagainst to separate the motor and pump chambers by the cylindrical bushing l6 mounted on the shaft and constituting a wear ring in cooperation with the rear wear ring I3 on flange 5. The bushing sleeve l6 also extends within the radial bearing 1 to support the shaft therein. The forward end of bushing It provides a bearing plate for rear thrust bearing The head of bushing '16 is confined between the shoulder H on shaft i0 and the rotating ring member of rear thrust bearing disposed between the bushing and the impeller ii.

The stationary member of the forward thrust hearing it is threaded into the housing 3 and is also supported axially against nozzle 2. The stationary member of forward wear ring i2 is secured to nozzle 2 and the rotating member thereof is carried by the front shroud of impeller l I.

A by-pass 88 through forward thrust bearing 04 connects with a passage E9 in nozzle 2 and permits pumped fluid from the discharge side of the impeller to flow through forward wear ring 92 to axial clearance passage 20 and thence to the suction inlet of nozzle 2. This improves the balance of the impeller and lubricates the wear ring.

A portion of the circulating fluid flows through the motor chamber to cool the motor by means of orifice 2! in discharge nozzle 3 and orifice 22 in housing i adjacent the forward flange 5. The by -pass 23 connects orifice 22 in housing l with the suction nozzle 2. The orifices limit the flow of fluid through the motor chamber.

The housing I is provided with four separate

longitudinal discharge passages

24, 25, 26, and 27 by casting the housing with a double wall at circumferentially spaced intervals. The inner circumferential walls 28 of the corresponding passages form a housing for the motor 4 and radially locate the stator of the motor 4 within the body portion of housing l. The

passages

24, 25, 26, and 21 with their respective inner walls 28 extend substantially the length of the motor chamber.

Also in the casting operation the housing I is provided at the forward end portion with a double volute construction comprising the upper volute 29 and the lower volute 30 as illustrated in Fig. 2 of the drawings. The

volutes

29 and 30 register with the discharge of the impeller at substantially diametrically opposite sides of impeller H.

The volute 29 terminates in passage 3i which is separated by the hollow rib 32 into the passages 24 and 25 above described. The hollow rib 32 is also formed as a part of housing i in the casting operation.

The lower volute 30 terminates in a passage similar to passage 3| and which is separated by the hollow rib 33 to connect with discharge passages 26 and 21 above described. The hollow rib 33 is similar to rib 32 and is formed as a part of housing I in the casting operations. The

ribs

32 and 33 constitute parts of the walls of

passages

25, 26 and 21 extending for substantially the length of the housing at opposite sides thereof and are closed at opposite ends at generally sharp I separation points.

The longitudinal passages 2|, 2!, 2t and 27 of housing I register with four similar passages 34 in the discharge nozzle 3. Passages 34 gradually merge into the circular discharge passages 35 at the flanged outlet of nozzle 3.

A generally short radial rib 33 is also cast integral with housing and is disposed in hollow rib 32 between housing I and the stator of motor 4. A key 31 secures the motor stator to rib 35 to prevent rotation of the stator in service. Dog point screw 38 extends through the enlarged end of rib 36 to additionally secure the stator of motor 4 and prevent axial movement thereof.

The motor 4 is circumferentially held by the cast inner walls 28 of housing i through which extend discharge passages 24, 25, and 21. Fluid pumped through the discharge passages eilectively cools the motor by conduction of heat from the stator thereof through the walls 23.

Fig. 4 illustrates volute 29, passage 3|, and passages 24 and 25 in detail. Passages 28 and 21 handling the discharge through lower volute 30 and the connecting passage therebetween are not shown in detail since the construction is similar to Fig. 4. Fig. 3 illustrates all four of the passages through housing I and Fig. 5 shows the fourpassages 34 of th discharge nozzle 3.

Hollow ribs

32 and 33 may be eliminated to provide only two longitudinal passages through housing I. The passages may also be increased in number by subdividing each of

passages

24, 25, 26 and 27.

The electrical connections for the motor may be made through one of the hollow ribs 32 as shown in Fig. 3.

The in-line type of centrifugal pump construction of the present invention provides a strongly supported housing for the motor while utilizing the supports therefor as discharge passages and as passages through which pumped fluid passes to cool the motor.

By providing a double volute discharge for the impeller and conducting the pumped liquid from these volutes through separated passages along the motor chamber to the discharge end of the pump, the casting of the housing is simplified and the eflicieney of the pump is increased over that of prior constructions.

In earlier constructions it was difficult to turn the discharge flow from the impeller to a longitudinal direction along the motor and at the same time spread the flow so that it substantially enclosed the motor on all sides for cooling the same, without reducing the efficiency of the impeller by reason of resistance to the discharge of liquid therefrom.

Various embodiments of the invention may be employed within the scope of the accompanying claims.

I claim:

1. In an in-line centrifugal pump of the class described, a shaft, an impeller and a motor,

said shaft being common to th impeller and the motor, a dual-walled housing surrounding said impeller and motor in radially spaced relation to the latter and having an inlet for the impeller at one end and an outlet for discharge of pumped fluid at the opposite end, and a series of circumferentially spaced longitudinally extending passages disposed between the'inner and outer walls of the housing to conduct pumped fluid from the impeller to said discharge outlet in substantial heat conductive relation to the inner wall of said housing to effect cooling of the motor, the walls of said passages being exposed on three sides to direct heat conductive relation with the fluid medium surrounding the motor inside the housing and in said radial space between the motor and housing.

2. In an in-line centrifugal pump of the class described, a shaft, an impeller and a motor, said shaft being common to the impeller and the motor, a dual-walled housing surrounding said impeller and motor in radially spaced relation to the latter and having an inlet for the impeller at one end and an outlet for discharge of pumped fluid at the opposite end. a series of circumferentially spaced longitudinally extending passages disposed between the inner and outer walls of the housing to conduct fluid from the impeller to said discharge outlet in substantial heat conductive relation to the inside wall of said housing to eflect cooling of the motor, and electrical connections for the motor passing through the housing in the space between two passages to avoid interference with the pumped fluid flowing through the passages.

3. In an ln-line centrifugal pump of the class described, a shaft, an impeller and a motor,

said shaft being common to the impeller and the motor, a dual-walled housing surrounding said impeller and motor in radially spaced relation to the latter and having an inlet forthe impeller at one end and an outlet for discharge of pumped fluid at the opposite end, a series of circumferentially spaced longitudinally extending passages disposed between the inner and outer walls of the housing to conduct fluid from the impeller to said discharge outlet in substantial heat conductive relation to the inside wall of said housing to effect cooling of the motor, and bleeder connections for the inside of said housing with said inlet and outlet to provide for controlled reverse circulation of pumped fluid through the housing around the motor and in contact. with the walls of said passages.

ANATOL J. HARLAMOFF.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS