US2514521A - Rotary pump - Google Patents

Description

July 11, 1950 a H. sHAr-'F ROTARY PUMP Filed Hay 2.0,. 1947 CflfTo ramen/J Patented July 11, 1950 UNITED STATES PATENT oFFicE I'he invention relates to ,rotary pumps and more particularly to vane type rotary pumps.

One object of the invention is to provide a 'pump of the above general character which is adapted to deliver a constant ow of fluid substantially free of pulsations.

yAnother object is to provide a vane type pump characterized by its simplicity of construction freedom from wear, and high operating eiliciency.

Other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment illusv trated in the accompanying drawing, in which:

Figure 1 is an end elevational view of a pump embodying the features of the invention.

Fig. 2 is a sectional view of the pump taken in a vertical plane substantially on the line 2-2 of Fig. 4.

Fig. 3 is a sectional view oi the pump taken in a. vertical plane substantially on the line 3,-3 o

Fig. 4.

Fig. 4v is a sectional view of the pump taken in a vertical 'plane substantially on the line 4-4 of Fig. 2.

Fig. 5 is a perspective view of the illler block which cooperates with the casing the rotor` to define the pump chamber.-

Fig. 6 is a perspective view of the rotor of the pump.

I Fig. 7 is a perspective view of the main assembly of the pump. I

While the invention issusceptible' of various modifications and alternative constructions, I have shown in the drawings and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the speciiic form disclosed, but intend to cover -all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

For purposes of illustration, the invention has been shown as incorporated in a manually operable pump particularly well suited for pumping gasoline or oil. It will be appreciated, however, that the pump may be arranged for power drive if desired, and that it may be used for pumping other liquids, or for compressing air or other gases.

In the preferred form shown, ythe pump comprises a casing Il having a pump chamber I I with two ports I2 and I3 either of which may serve as inlet or outlet ports. Joumaled in the casing I0 and eccentrically disposed within the chamber Il is arotor I4 carrying a plurality of blades or 55 2 vanes shiftable generally radially thereoffor coaction with the walls of the chamber. When the rotor is turned clockwise, as viewed in Figs. 2 and 3, fluid is drawn through the port I2 into the working portion of the pump chamber and dis- 'charged through the port I3, the direction of ow being reversed when the rotor is turned in a counterclockwise direction. As a matter of convenience, it will be assumed that the rotor is normally turned in a clockwise direction and the ports I2 and I3 will be referred torespectively as inlet and outlet ports in the following description of the pump and its mode of operation.

In the particular pump shown, the rotor I4 is provided with two vanes I5 and I6 assembled as a'unit and slidably received in .a recess or slot Il extending diametrically through the rotor. The vanes I5 and I6 are alike in construction, each comprising a generally rectangular metal block having its outer end portion rounded, as indicated at Il, to provide substantially a line contact with the walls of the pump chamber.

As shown in Figs. 1, 2 and 4, the casing I0 is constructedvin two sections, including a main section-2li having a cylindrical recess opening at one side and a cover section 22 removably secured to the main section as by screws 22' to close the open end of the receas 2|. The pump sections are formed with hollow bosses 23 and 2l opening into the recess 2| through the ports .|2 and I3 which are located in the end walls of the recess instead of in the peripheral wall as is customary in pumps of the type under consideration. This arrangement reduces wear on the vanes I5 and I6 and assists in providing a uniform delivery of iiuid, as will appear presently. The bosses 23 and 24 are arranged respectively in pairs, each communieating with common ducts or pipes 25 and 26 by which the pump may be connected to the apparatus with which it is to be associated. While the pipes 25 and 26 have been shown as formed integrally with the casing section 20, it will be understood that they may be connected thereto by screw-threaded or other separable connections. if desired.

To facilitate manufacture of the pump, the pump chamber II is formed by the walls of the recess 2| in cooperation wth an arcuate filler block 3| ntted into the recess between the ports I2 and I3. 'Ihe inner and outer surfaces of the ller block are formed on radii having a common center, the radius of the outer surface being substantially equal to the radius of the recess 2|. Accordingly, when the block is installed in the 3 recess the center of its surfaces coincides` with the center of the recess.

The inner surface of the filler block is formed the ller block 3l. as shown in Figs. 2, 3, and 5.

By mounting the rotor I4 with its axis coincident with the axis of the pump chamber, the working portion of the chamber II is thus formed with a uniform cross-sectional area throughout the major portion of its length, the area decreasing abr-uptly at the ends of the chamber as determined by the slope of the cam surfaces 32 and 33.

Referring now to Figs. 4 and 6 of the drawings, the rotor I4 comprises a cylindrical body having axially projecting shafts 35 and 36 on opposite ends formed integrally therewith or rigidly secured thereto. In the assembled pump structure the shaft 35 is journaled in a bearing cup 31 formed in the end wall of the main casing sectionv 25 and the shaft 36 is journaled in a bearing 38 formed on the cover section 22 of the casing. The latter shaft is arranged to project through the cover section for attachment of suitable driving means, such as a gear or pulley when power drive is contemplated, or for a hand crank 39 when the pump is to be driven manually. A suitable gland 40 is threaded on the outer end of the bearing'33 and provided with the usual packing to prevent leakage around the shaft 36.

As shown in Fig. 6, the end of the shaft 36 is milled to provide opposed ilat surfaces 4I for engagement ina generally rectangular aperture in the crank 39 so as to provide a nonrotative connection therebetween. The crank is held in` assembled relation with the shaft by a washer 42 (Figs. 1 and 4) and a screw 43 threaded into the end of the shaft. A knob 44 is rotatably mounted on the outer end of the crank 39 for convenient manual manipulation.

As indicated heretofore, the recess or slot I1 extends diametrically through the rotor I4 and, as shown in Fig. 6, it also extends the full length of the rotor. The vanes I and I6 are dimensioned to provide a sliding llt with the walls of the slot I1 and of a width such as to provide a working fit with the end walls of the pump chamber II as the vanes approach the end of the chamber. whereby the fluctuations in delivery or pulsation is eliminated or substantially reduced. More particularly, the vanes I5 and I5 are constructed and the ports I2 and I3 are related thereto in a manner such as to admit fluid into the interior of the slot I1 as either one of the vanes passes the inlet 'port I2, to momentarily trap the uid in the recess and to discharge the fluid therefrom through the outlet port I3 as the other one of the vanes passes the latter port. For this purpose each vane is formed with one or more passages 50 extending from the inner end of the vane longitudinally to a point closely adjacent the outer end and then laterally to open at a port 5I in the side wall of the vane. In the exemplary pump each vane is provided with two such passages and the springs1 45 are seated therein as shown in Figs. 4 and To permit the required cooperation between the ports 5I, the vanes I5 and I6, and the ports I2 and I3 of the pump chamber, the latter ports are spaced apart slightly less than 180, that is, closely adjacent but at the same side of a plane passing through the common axis of the rotor and the pump chamber. Accordingly, as each vane rides down the cam surface 32, as shown in Fig. 3, it establishes communication between the port I 2 and the interior of the slot I1 by way of the port 5I and passage 50 in the vane. During such outward movement of the vane, the companion vane is held in fixed relation to the rotor by engagement with the walls of the pump chamber II and consequently the outward movement of the one vane increases the volumetric capacity of the cavity between the vanes, with the result that iluid is drawn from the inlet port into the recess. The

fluid is momentarily trapped in the recess Il as the first-mentioned vane moves out of registration with the port I2 and before thecompanion vane registers with the outlet port I3.

In the vfurther rotation of the rotor, the vane which has just passed the inlet port is held in fixed relation with respect to the rotor I4 and the ports 5I of that vane are eiectually sealed by end walls of the pump chamber. As the companion vane now l:rides up on the cam surface 33, it is shifted inwardly of the rotor, thereby decreasing the volumetric capacity of the cavity between the two vanes and forcing the fluid therefrom through the passages 50 of the vane and the ports 5I lwhich register with the outlet port I3. In this way the decreasing discharge from the working portion of the pump chamber vII is supplemented by the piston-like action of the vanes so that a substanstant volume of fluid until it reaches the cam l uid from the working portion of the pump tially constant flow of fluid is maintained during the interval in which the respective vanes pass from active to inactive positionand vice versa.

In order to provide a supplemental flow of sufiicient volume to eliminate the pulsations in the pump delivery, the vanes I5 and I6 are made re1a tively thick and'the slot I'I is correspondingly dimensioned. The thickness is determined of course by the other dimensions of the pump.

It will be apparent from thev foregoing that the i in construction and capable of being manufactured at low cost.

I claim as my invention:

1. In a pump, in combination, a casing having a cylindrical recess therein, inlet and outlet ports, each of said ports beingA a pair of opposed apertures opening respectively in the opposing end walls of the recess adjacent the peripheral wall thereof, said ports being located on one side of and closely adjacent a plane intersecting the axis of the recess, a rotor mounted in said recess with its axis coincident with the axis of the recess, oppositely projecting vanes disposed within a slot extending diametrically through said rotor and slidable relative thereto for cooperation with the walls of the recess, an arcuate ller block mounted in said recess at the same side of said plane as said ports and defining with the walls of the recess a pump chamber having one Wall section engageable with the peripheral wall of the rotor and an opposed wall section spaced therefrom, said vanes in passing over said opposed Wall section acting to transfer fluid from said inlet port to said outlet port, and inclined cam surfaces formed on the ends of said filler block, one of said cam surfaces being located adjacent the outlet port and operative to cam the vanes into the rotor in their passage across the outlet port and the other of said cam surfaces being located adjacent the inlet port to permit the projection of the vanes from the rotor in their passage across the inlet port, each 0f said vanes having opposed lateral apertures adjacent the outer ends thereof and a longitudinal passage extending from said apertures to the inner ends of said vanes so that said vanes are operative in their outward movement to admit fluid from said inlet port into said Slot between the vanes and in their inward movement to discharge the fluid from the slot through said outlet port to supplement the discharge of fluid from said pump chamber.

2. A rotary pump comprising, in combination, a casing defining a generally cylindrical recess having closed ends forming opposed end walls and opposed arcuate side walls of different radii formed on a common center and connected by cam surfaces, said casing having inlet and outlet ports opening in said opposed 'end Walls of the recess respectively adjacent said cam surfaces, each of said ports being a pair of opposed apertures opening respectively in said opposed end walls, a cylindrical rotor journaled in .said casing with its axis on said common. center, said rotor having a running fit at one side with the wall of shorter radius and being spaced at the opposite side from the wall of longer radius to form therewith a working chamber of substantially uniform cross-sectional area throughout the major portion of its length, said rotor having a slot extending diametrically therethrough, a pair of vanes slidably mounted in said slot to project at opposite sides of the rotor, spring means interposed between said vanes yieldably urging them outwardly against the` side Walls of the recess, said vanes 'being operative in the rotation of said rotor to move fluid through said Working chamber from said inlet port to said outlet port and having passages operative in the movements of the vanes into and out of said slot as-they ride over said cam surfaces to admit fluid to the interior of the slot at said inlet port and to force the uid from the slot through said outlet port to supplement the discharge from the working chamber of the pump. said ports and said cam surfaces being spaced apart circumferentially of said recess slightly less than one hundred eighty degrees so as to permit a momentary full projection of both vanes simultaneously as one vane passes the inlet ports and the companion vane approaches the outlet port, whereby to increase the volume of the supplemental discharge to a maximum. Y

' ERNEST H. SHAFF.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 124,820 Holmes Mar. 19, 1872 154,100 Stott Aug. 11, 1874 165,623 Smthells July 13, 1875 304,962 Sager Sept. 9, 1884 319,093 Hassinger June 2, 1885 902,731 Hord Nov. 3, 1908 1,245,691 Deysher Nov. 6, 1917 1,317,353 Crago Sept. 30,` 1919 1,558,696 Marion Oct. 27, 1925 1,854,692 Cooper Apr. 19, 1932 FOREIGN PATENTS Number Country Date 59,234 Switzerland' Apr. 4, 1912 433,488 Great Britain Aug. l5, 1935 440,212 Great Britain Dec. 23, 1935

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