US3128708A - Pump - Google Patents

Description

April 14, 1964 Filed Dec. 19, 1960 FIG. I.

.1. c. HENNING 3,128,708

PUMP

3 Sheets-Sheet 1 INVENTOR JAMES C. HENNNG ATTORNEYS April 14, 1964 J. c. HENNING PUMP 3 Sheets-Sheet 2 Filed Dec. 19, 1960 INVENIOR JAMES C. HENNING ATTORNEYS United States Patent Ofiice 3,128,708 Patented Apr. 14, 1964 Jersey Filed Dec. 19, 1960, Ser. No. 76,831 1 Claim. (131. 103-5) This invention relates to vane pumps. Particularly, it relates to a vane pump having a vaned stator which encircles a cavity in which a rotary cam or impeller is mounted.

Vane pumps of this general type are known but, in the past, the high pressure and low pressure ports have been formed in the rotary cam. According to the present invention, the high pressure and low pressure ports are formed in rotary cheek plates fastened to the opposite side faces of the rotary cam. The ports in each plate comprise a pair of diametrically opposed arcuate ports. The ports in the high pressure plate afford communication between a high pressure manifold and the impeller cavity, and those in the low pressure plate afford communication between a low pressure manifold and the impeller cavity. The two sets of ports are angularly spaced from one another in such a way that the angular interval between the ends of the high pressure ports and the ends of the low pressure ports is at least as large as the angular interval between successive vanes in the stator. A groove is formed in the inner face of the cheek plate at the opposite ends of each low pressure port. These grooves provide restricted flow from the high pressure regions of the impeller cavity to the low pressure port. These ports alleviate shock loading which might otherwise occur during transition from one pres sure level to the other. This results in quieter operation and prevents damage to the pump which might otherwise be produced by shock loading.

One of the advantages afforded by locating the ports in cheek plates carried by the rotary cam is the fact that the position of the ports, in relation to the impeller cavity, remains unchanged which leads to improved valving ac tion.

Another advantage is that the fabrication of the ports is greatly simplified as compared to the fabrication of the ports when they are located in the rotary cam itself, as was characteristic of the prior art. Finally, the bearing surface of the cam is uniform and wear is evenly distributed across the vane ends.

The preferred embodiment of the invention will be described having reference to the accompanying drawings, in which:

FIG. 1 is a view substantially in vertical axial section of a pump embodying the invention. In this section, the high pressure ports have been rotated through an angle of approximately 45 in the clockwise direction from the position of these ports illustrated in FIG. 2 so that they show in full line. Similarly, the low pressure ports have been rotated through an angle of approximately 45 in the clockwise direction from the position of these ports as illustrated in FIG. 3. Similarly, one of the vanes has been rotated into this plane of section.

FIG. 2 is a transverse section on the line 22 of FIG. 1.

FIG. 3 is a transverse section on the line 33 of FIG. 1.

FIG. 4 is a plan view of the inner face of the low pressure plate.

FIG. 5 is a plan view of the outer face of the low pressure plate.

FIG. 6 is a plan view of the inner face of the high pressure plate.

Refer first to FIG. 1. The housing comprises end sections 11 and 12 and a central stator section 13. Leakage between the mating faces of these sections is prevented by means of conventional seals indicated at 14. Journalled in the end section 11 is a drive shaft 15. This shaft is carried by a plain bearing bushing 16 and an anti-friction ball bearing 17 A conventional low pressure seal 18 encircles the shaft 15 between the bearings 16 and 17. The inner end of the shaft is provided with splines 19 on which is carried a rotor assembly. This assembly comprises a cam 21, a high pressure cheek plate 22, and a low pressure cheek plate 23.

As shown in FIG. 4, the low pressure plate 23 is provided with two diametrically opposed arcuate ports 24 extending therethrough. Also as shown in this figure, the opposite ends of each of the ports 24 are provided with restricted tails 25; these tails taking the form of grooves which do not extend through the cheek plate.

Referring to FIG. 5, it will be seen that the outer face of the low pressure cheek plate 23 is provided with a plurality of radial impeller vanes 26.

As shown in FIG. 6, the high pressure cheek plate 22 is provided with diametrically opposed arcuate ports 27 which extend through the plate. Near the outer pe riphery of the cheek plate 22 there is provided an encircling groove 28. Between the groove 23 and the ports 27 there is a second encircling groove 29.

Referring again to FIG. 1, it will be seen that the diameter of the cheek plates is larger than the length of the major axis of the cam 21. Thus, the outer peripheral portions of the cheek plates 22 and 23 abut against the plane, parallel side faces of the vaned stator 13. The diameter of the cheek plates 22 and 23 is such that they overlie the exposed edges of the radial vane slots 31 (see FIGS. 2 and 3) which are formed in the stator 13. Vanes 30 are mounted in the vane slots 31. These vanes are of the type shown in the Rosen Patent 2,393,223. The stator 13 encircles a right circular cylindrical impeller cavity 32 in which the cam 21 rotates. The diameter of the impeller cavity is equal to the length of the major axis of the cam 21, and the thickness of the stator 13 is the same as the thickness of the cam 21. An antifriction thrust bearing 33 is located in the encircling groove 29 formed in the high pressure plate 22 and reacts between that plate and the side face of the stator 13. The cheek plates 22 and 23 and the cam 21, which make up the rotor assembly, are held in assembled relationship by means of machine screws 34.

Formed in the-end section 11 is an encircling high pressure manifold 35. A high pressure connection 36 communicates with manifold 35. A low pressure manifold 37 is provided in the end section 12 and communicates with an inlet connection 38. The end plates 11 and 12 and the vaned stator 13 are held in assembled relationship by means of machine bolts 39. A series of ports 41 extend through the cheek plate 22 and communicate with the groove 28. In this way, high pressure fluid is admitted from the manifold 35 to the outer ends of the vane slots 31. The vanes are thus fluid pressure-biased into contact with the cam 21.

As is best shown in FIGS. 2 and 3, the cam 31 is of generally elliptical form. It includes two diametrically opposed constant diameter portions indicated at A, and two shorter constant diameter portions indicated at B. The constant diameter portions are connected by a transition portion whose diameter is not constant. The profile of these transition portions is preferably so selected that the vanes move with harmonic motion. The arrows C on FIGS. 2 and 3 indicate the direction of rotation of the rotor assembly.

The low pressure connection 38 is the pump inlet connection and the high pressure connection 36 is the discharge connection. If it is assumed that the pump has been standing idle and is started up, the impeller vanes 26 on the low pressure cheek plate will draw fluid through the inlet 38 and impart thereto a velocity head suificient to cause fluid to enter impeller cavity 32 through the inlet ports 24. This fluid enters the expanding working space 42 (see FIG. 3). If the vane 30, between the working space 42 and the adjacent working space 43, is retracted, of course this fluid will enter both working spaces. It will also enter the working space 44 if the vane 30, between the working spaces 43 and 44, is retracted.

As shown in FIG. 2, the working space 44 is in open communication with the discharge port 27. Thus, fluid under pressure will enter the manifold 35 and will be transmitted therefrom through the ports 41 and the groove 28 to the outer ends of the vane slots 31. This fluid under pressure will cause any vanes which were retracted when the pump was started to move into contact with the cam 21. Continued operation of the pump with the vanes in active position will result in the development of high pressure in the discharge manifold 35.

The vane construction is such that the fluid pressures on opposite ends of the vanes result in the vanes being partially pressure balanced so that excessive force urging the vanes into contact with the cam 21 will not be developed. This partial pressure balance is more fully described in the Rosen patent earlier referred to.

It will be noticed that the surface of the cam, which is in contact with the vane, is not interrupted by any port openings or the like. Hence, a constant bearing area is provided between the vanes and the cam which assures uniform wear of these coacting parts.

A pump of the type described has the following advantageous characteristics:

The discharge flow is uniform because of the constant relationship between the working chamber and the dis charge port. This constant relationship results from the mounting of the cheek plates rigidly on the rotor;

Close running clearances may be used;

The cam is easily machined;

Low speed operation of the pump is possible because the vanes are fluid pressure-biased into active position.

It is possible to operate the pump at high rotary speeds without cavitation because of the presence of the impeller vanes 26 which impart a velocity head to the entering fluid.

While the illustrated embodiment is preferred, the inventive concept is not limited to the precise construction illustrated, and no limitation to this construction is implied except as may be expressed in the appended claims.

What is claimed is:

A vane pump comprising in combination a housing;

a drive shaft journalled therein, said housing including a one-piece stator element encircling a cylindrical impeller cavity and having plane, parallel side face portions adjacent the periphery of said cavity and having a plurality of spaced vane slots, each slot having a width equal to the thickness of the stator element in the region of said plane, parallel side face portions and extending radially outward from said impeller cavity; vane means reciprocable in each vane slot; a rotor element of generally elliptical form connected to said shaft in said cavity, said rotor element having a thickness equal to the width of the slots in the stator element and a major axis equal in length to the diameter of said cavity; high pressure and low pressure valve plates abutting the opposite faces of said rotor element and connected with said shaft so as to rotate therewith, said plates extending outward beyond the periphery of the rotor to overlie the plane, parallel side face portions of the stator element and thus close the sides of the vane slots; at high pressure manifold in the housing adjacent the high pressure valve plate; a low pressure manifold in the housing adjacent the low pressure valve plate, each valve plate having a pair of diametrically opposed arcuate ports extending therethrough and affording communication between the high pressure manifold and the impeller cavity and between the low pressure manifold and the impeller cavity, the angular interval between the ends of the high pressure ports and the ends of the low pressure ports being substantially equal to the angular interval between adjacent vanes, means defining a constantly open flow path from the high pressure manifold to the vane slots beneath the vanes therein whereby fluid under pressure from said manifold urges the vanes radially inward; radial impeller elements mounted on the side of the low pressure valve plate which is remote from the rotor element, and extending outward from the central portion of that valve plate into the low pressure manifold; and an inlet connection formed through said housing adjacent the central portion of the low pressure valve plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,784,578 Cornwell Dec. 9, 1930 1,927,799 Mann Sept. 19, 1933 2,232,951 Kosian Feb. 25, 1941 2,373,457 Chisholm Apr. 10, 1945 2,513,446 Brown July 4, 1950 2,521,592 McManus Sept. 5, 1950 2,985,110 Burt et al May 23, 1961 FOREIGN PATENTS 978,151 France Nov.22, 1950

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