US2718351A - Rotary pump - Google Patents

Description

P 0, 1955 F. M. KIRKPATRICK ROTARY PUMP Filed Dec. 31, 1952 United States Patent Ofifice 2,718,351 Patented Sept. 20, 1955 ROTARY PUMP Floyd M. Kirkpatrick, Erie, Pa., assignor to General Electric Company, a corporation of New York Application December 31, 1952, Serial No. 328,961

4 Claims. (Cl. 230-137) My invention relates to pumps and more particularly to pumps of the rotary type.

It is an object of my invention to provide an improved rotary pump having an increased eificiency.

It is a more specific object of my invention to provide an improved ball pump of the type disclosed in my earlier Patent 2,611,534 including provision for minimizing leakage from the high pressure side to the intake.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In carrying out the objects of my invention the basic pump structure disclosed in my earlier Patent 2,611,534 is employed. In order to avoid leakage from the high pressure side to the intake during the crossover of the piston segments a slide moving transversely in the inlet recess is employed for blocking the intake passage during this portion of the operating cycle.

For a better understanding of my invention reference may be had to the accompanying drawing in which:

Fig. 1 is a view, partly broken away, of a refrigerating unit including a compressor embodying my invention.

Fig. 2 is an enlarged plan view, partly broken away, of the compressor shown in Fig. 1.

Fig. 3 is a View of the rotor of the compressor, showing the piston segments in a different position than in Fig. 2.

Fig. 4 is a view similar to Fig. 3 showing the piston segments in still another position.

Fig. 5 is an elevation view, partly in section, of a portion of the compressor showing the piston segments in the same position as in Fig. 4.

In the following description, the pump is described in connection with its application as a compressor in a refrigerating apparatus but it will be apparent that it may be utilized in many other applications where pumping of fluid is required. Referring now to Fig. 1, there is shown a hermetically sealed case 1 within which is mounted a compressor 2. The compressor is positioned within the housing by rings 3 and 4 which fit grooves in the case 1 and engage opposite faces of the compressor 2. The compressor is driven in any suitable manner as by an electric motor (not shown) incorporated within the case 1 and connected to the compressor through a drive shaft 5. Compressed refrigerant is discharged from the compressor through conduits 6 and 7 into a common conduit 8 from which it is circulated through the refrigerating system (not shown). Vaporized refrigerant is returned from the refrigerating system through a conduit 9 which discharges the refrigerant into the interior of the case 1. Vaporized refrigerant within the case 1 is taken into the compressor through intake conduits 10 and 11, the open ends of which are positioned above the level 12 of any liquid refrigerant or oil within the case 1.

As shown in more detail in Fig. 2 a compressor is driven through the shaft 5 which is supported within a bearing 13." Compressor includes a housing 14 which is composed of two complementary parts 15 and 16. The

inner surface of each of the housing parts 15 and 16 is curved so that when the two parts are assembled a spherical surface, forming a spherical chamber, is provided within the interior of the housing. In the form shown the housing parts are of such width that the ends of the sphere formed by the inner surfaces thereof are truncated. However, if desired, the housing could be enlarged and the inner surfaces of the parts 15 and 16 continued to provide a substantially complete sphere. The housing parts 15 and 16 are held in sealing engagement by devices such as screws 19 which pass through the upper housing part 15 and are arranged in threaded engagement with the lower housing part 16.

A rotor 17 is provided within the housing, the rotor being driven by the shaft 5. The outer surface of this rotor is curved to provide a generally spherical surface having the same radius of curvature as the inner surface of the housing so as to rotate smoothly in engagement therewith. In the form shown, the rotor also is truncated, providing flat faces 18 and 18'. An arcuate ring 20 which fits within a groove 21 in the housing and engages the face 18 of the rotor may be employed to assist in resisting oscillation of the axis of rotation of the rotor, although reliance for this purpose may be placed entirely on the bearing 13.

The rotor is provided with two circumferential grooves 22 and 23. These grooves intersect each other at diametrically opposite points of the rotor, one such intersection being indicated at 24. These grooves are inclined at equal angles with respect to a plane perpendicular to the axis of rotation of the rotor and extending through the two points of intersection of the grooves 22 and 23. In order to effect pumping of fluid a piston segment 25 is positioned within the groove 22 and a similar piston segment 26 is positioned within the groove 23. The outer spherical surfaces 27 and 28 of the piston segments 25 and 26 respectively are in line with the spherical surface of the rotor 17 and hence are in engagement with the spherical surface provided by the interior of the housing 14. Each of the piston segments is in the form of a semi-circular or half-annular section extending on a great circle of the rotor 17 substantially half the circumference thereof.

To effect pumping of fluid by the compressor, it is necessary to restrain the piston segments 25 and 26 against rotation with the rotor while permitting lateral oscillation of the segments during such rotation of the rotor. This is accomplished by providing a pin or projection on each of the piston segments pivotally engaging a slide or block which is slidably positioned within a transverse slot or recess in the housing 14. In the drawing one such slide or block 29 is shown pivotally connected by a pin 30 to the piston segment 26. It will be apparent, however, that exactly the same construction is employed at the diametrically opposite point for pivotal connection with and restraint of the other piston segment 27. Since my invention can be fully understood, in view of the complete disclosure in my earlier Patent 2,611,5 34, by a description of one such slide, illustration and description of a corresponding oppositely mounted slide has been omitted. The slide 29 is slidably positioned for transverse movement, i. e., movement generally transverse of the piston segments, within an elongated transverse recess 31 formed in the housing adjacent the rotor 17. The slide 29 is substantially the same Width as the width of the recess 31 and is substantially the same thickness as the depth of the recess 31. v

In the following description, the recess 31 is referred to as the intake recess, one intake conduit 11 being connected to this recess generally centrally of the length of the recess and providing an intake port, as indicated at 32. A second elongated transverse recess 33 is provided in the housing 14, this recess being spaced from but adjacent to the recess 31. The elongated transverse recess 33 will be referred to as the discharge recess, this recess being connected to the discharge conduit 6. It will be noted that the recesses 31 and 33 are circumferential-1y spaced on opposite sides of the cross over point of the piston segmen-ts. The crossover point as used in this specification indicates the point of intersection of the grooves 22 and 23 when the rotor is in a position that the ends of the piston segments are disposed in the region of the intersection, as shown in Fig. 2. Another cross-over point, of course, occurs diametrically opposite from the one shown in Fig. 2. Although not shown, it will be realized that corresponding intake and discharge recesses are provided at diametrically opposite positions, also adjacent to each other and spaced on opposite sides circumferentially of the other crossover point of the piston segments.

The pumping is accomplished in the structure herein disclosed in the same manner as in the basic pump structure shown in my earlier Patent 2,611,534. Thus, the rotor 17 moves, e. g., in the direction indicated by the arrow, and the piston segments 25 and 26 are restrained from circumferential or rotating movement but are allowed to oscillate between the various successive positions, as shown, for example in Figs. 2, 3 and 4. The position of the piston segments illustrated in Fig. 3 shows the segments after a 180 rotation of the rotor from the position shown in Fig. 2. Figs. 4 and 5 show the elements after an additional 90 rotation of the rotor. For convenience in description and for ciarity the intake recess 31 and the discharge recess 33 have been superimposed in dotted lines on the rotor in Figs. 3 and 4.

As described in detail in my aforementioned patent, the rotation of the rotor and its grooves 22 and 23 and the oscillation of the piston segments 25 and 26 results in a pumping of the refrigerant from the intake conduit and intake recess to the discharge recess and discharge conduit. A reference to Fig. 4 illustrates this operation. As there is seen, one face 34 of piston segment 26 blocks one end of the circumferential groove 23. As the rotor revolves in the direction indicated, the size of the groove between the face 34 of the piston segment 26 and the end 35 of the piston segment 25 increases causing vaporized refrigerant to be drawn into this space from the intake conduit 6 through intake port 32, which is superimposed in dotted lines in Figs. 3 and 4. At the same time, one end of the circumferential groove 22 is blocked by a face 36 of the piston segment 25. As the rotor rotates in the direction indicated by the arrow, the size of the circumferential groove 22 between the face 36 of the piston segment 25 and the end 37 of the piston segment 26 progressively decreases so that vaporized refrigerant taken into this space in the previous half cycle of operation is compressed and pumped out through the discharge recess 33 which is in communication with the groove 22. This compressed refrigerant also passes through a discharge port 33, superimposed in dotted lines in Figs. 3 and 4, to the discharge conduit 11. The operation of this aspect of my pump is described in great detail in my aforementioned Patent 2,611,534, and reference may be had to that patent for further description, if felt necessary, of the details of the basic pump and the pumping operation. No further description of this operation is felt necessary here since the specific invention here disclosed has to do with a particular improvement of this basic pump.

in Figs. 2 and 3 the piston segments are shown at what may be referred to as a crossover point, that is a point where the ends of the piston segments are disposed in the region of the intersection 24 of the circumferential grooves 22 and 23. In Fig. 2 the piston segments are illustrated at one crossover point and in Fig. 3 at a second crossover point occurring after a 180 rotation of the rotor 17. It will be seen that there is no communication between the Cir intake recess and discharge recess when the rotor is in the position shown, for example, in Fig. 4 since, as mentioned previously the spherical surface of the rotor fits closely adjacent the spherical surface of the housing 14, and since the ends 35 and 37 of the piston segments extend somewhat beyond the corresponding recesses 33 and 31, all as set forth in my earlier Patent 2,611,534. However, there is communication between the two circumferential grooves 22 and 23 during the short period when the piston segments are at the crosover point. In the form of invention shown in my aforementioned patent, a communication between the high pressure side and the intake conduit was possible during this relatively short period of rotation of the rotor and hence some reduction in efficiency resulted because of this leakage of compressed refrigerant into the intake port and intake conduit. The invention in the present application has specifically to do with positively blocking any flow of refrigerant from the high pressure side into the intake conduit during this portion of the operating cycle of the compressor when the piston segments are at the crossover point. This is accomplished by the slide 29, its position within the corresponding intake recess 31, and its relationship to the intake port 32. The width of the slide 29 is substantially the same as the width of the corresponding recess 31 so that the slide moves smoothly along the recess during its oscillating movement. More pertinent, however, the thickness of the slide 29 is substantially the same as the depth of the recess 31 so that the upper surface 39 of the slide, as viewed in Fig. 5, rides closely adjacent the surface 40 of the recess 31. It can be seen, therefore, that the slide 29 is positioned so as to seal the intake port 32 when the slide 29 extends thereacross.

In the position of the parts shown in Figs. 4 and 5, the slide 29 is clear of the intake port 32 so that it has no effect on the flow of refrigerant inwardly through the intake conduit 6 into the inlet recess 31 and then into the communicating groove in the rotor 17. When the rotor is in the position shown in Fig. 2 or Fig. 3, however, that is when the piston segments are at the crossover point or stated otherwise in the region of the intersection of the grooves 22 and 23, the slide 29 occupies a position completely blocking the intake port 32. This is illustrated by showing the port 32 superimposed in dotted lines and can be further visualized by the realization that at the crossover point the slide shown in Fig. 5 would be disposed substantially centrally of the length of the elongated transverse intake recess 31. Since, as stated previously, the surface 39 of the slide rides closely adjacent to the surface 40 of the recess, the slide in this central position blocks the intake port 32. Hence, under these circumstances, flow of compressed refrigerant from the high pressure side through the communicating circumferential grooves 22 and 23 and into the intake conduit is blocked. This blockage of such flow increases the efficiency of the pump, since the flow of refrigerant in this manner represents a loss in the operation of the pump.

The slide 29 is elongated and is made of sufficient length so that during the period of rotation when the piston segments are in the region of the crossover point and hence when such flow of refrigerant from the high pressure side to the intake conduit would be possible, one end or the other of the slide 29 completely blocks the intake port 32. Thus in the crossover position shown in Fig. 2, the right-hand portion of the slide 22 insures this blocking of the intake port and in the position shown in Fig. 3, the left-hand end of the slide 29 effects this locking of the intake port. A check valve may be employed in the discharge conduit 8 or, alternatively, as suggested in my Patent 2,611,534, a check valve may be used in each of the discharge conduits 6 and 7, preferably close to the discharge ports to further assist in minimizing flow of refrigerant from the high pressure side to the intake.

The invention has been described and illustrated by reference to a single intake and discharge recess and a single slide 29, but it will be realized, as pointed out above, that the identical structure is provided at the diametrically opposite side of the compressor. Duplicate illustration of this structure is not felt to be necessary for an understanding of my invention, particularly since this duplicate illustration is fully given in my aforementioned Patent 2,611,534.

While I have shown and described a specific embodiment of my invention, I do not desire my invention to be limited to the particular construction shown and described, and I intend by the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A pump comprising a housing having a spherical chamber therein, a rotor within said chamber, said rotor having a spherical surface arranged to contact the surface of said chamber, said rotor having 'a pair of circumferential grooves formed in said spherical surface thereof, said grooves intersecting each other at two diametrically opposite points, a semicircular piston segment positioned in each of said grooves, two diametrically opposite elongated intake recesses within said housing adjacent said spherical surface of said rotor, two diametrically opposite elongated discharge recesses within said housing adjacent said spherical surface of said rotor, each of said discharge recesses being positioned adjacent one of said inlet recesses, all of said recesses extending transversely with respect to said grooves, one of said intake recesses and one of said discharge recesses communicating with each of said grooves, each of said discharge recesses being circumferentially spaced from the adjacent one of said intake recesses, adjacent intake and discharge recesses being disposed on opposite sides of a plane extending between the ends of said segments and along the axis of said rotor, an elongated slide pivotally connected to one of said piston segments and slidably received within one of said intake recesses for maintaining said one of said piston segments against rotation with said rotor while permitting lateral oscillation of said one of said piston segments, a second elongated slide pivotally engaging the other of said piston segments and slidably received within the other of said intake recesses for maintaining said other of said piston segments against rotation with said rotor while permitting lateral oscillation of said other of said piston segments, an intake port in the bottom of each of said intake recesses and centrally of the length thereof, each of said ports providing for communication between the corresponding one of said intake recesses and a corresponding inlet conduit, each of said elongated slides being of substantially the same thickness as the depth of its corresponding recess whereby said slides block said intake ports when the ends of said piston segments are in the region of the intersections of said grooves.

2. A pump comprising a housing having a spherical chamber therein, a rotor Within said chamber, said rotor having a spherical surface arranged to contact the surface of said chamber, said rotor having a pair of circumferential grooves formed in said spherical surface thereof, said grooves intersecting each other at two diametrically opposite points, a semicircular piston segment positioned in each of said grooves, two diametrically opposite elongated intake recesses within said housing adjacent said spherical surface of said rotor, two diametrically opposite elongated discharge recesses within said housing adjacent said spherical surface of said rotor, each of said discharge recesses being positioned adjacent one of said inlet recesses, all of said recesses extending transversely with respect to said grooves, one of said intake recesses and one of said discharge recesses communicating with each of said grooves, each of said discharge recesses being circumferentially spaced from the adjacent one of said intake recesses, adjacent intake and discharge recesses being disposed on opposite sides of a plane extending between the ends of said segments and along the axis of said rotor, an elongated slide pivotally connected to one of said piston segments and slidably received within one of said intake recesses for maintaining said one of said piston segments against rotation with said rotor while permitting lateral oscillation of said one of said piston segments, a second elongated slide pivotally engaging the other of said piston segments and slidably received with in the other of said intake recesses for maintaining said other of said piston segments against rotation with said rotor while permitting lateral oscillation of said other of said piston segments, an intake port in the bottom of each of said intake recesses and centrally of the length thereof, each of said ports providing for communication between the corresponding one of said intake recesses and a corresponding inlet conduit, each of said elongated slides being of substantially the same thickness as the depth of its corresponding recess and of such length that it overlaps its corresponding intake port when the ends of said piston segments are in the region of the intersections of said grooves whereby said slides block said intake ports when the ends of said piston segments are in the region of the intersections of said grooves.

3. A housing having a spherical chamber therein, a rotor within said chamber, said rotor having a spherical surface arranged to engage the surface of said chamber, said rotor having a pair of circumferential grooves formed in said spherical surface thereof, said grooves intersecting each other at two diametrically opposite points, a semicircular piston segment positioned in each of said grooves, two diametrically opposite elongated intake recesses Within said housing adjacent said spherical surface of said rotor, two diametrically opposite elongated discharge recesses within said housing adjacent said spherical surface of said rotor, each of said discharge recesses being positioned adjacent one of said inlet recesses, all of said recesses extending transversely with respect to said grooves, one of said intake recesses and one of said discharge recesses communicating with each of said grooves, each of said discharge recesses being circumferentially spaced from the adjacent one of said intake recesses, adjacent intake and discharge recesses being disposed on opposite sides of a plane extending between the ends of said segments and along the axis of said rotor, a pair of elongated slides each pivotally connected to one of said piston segments and each slidably received within one of said in take recesses for maintaining said piston segments against rotation with said rotor while permitting lateral oscillation of said piston segments, an intake conduit communicating with each of said intake recesses, and means comprising said elongated slides for blocking said intake conduit when the ends of said piston segments are in the region of the intersections of said grooves, whereby said elongated slides prevent leakage from the discharge of said pump to said intake conduit.

4. A pump comprising a housing having a spherical chamber therein, a rotor within said chamber, said rotor having a spherical surface arranged to engage the surface of said chamber, said rotor having a pair of circumferential grooves formed in said spherical surface thereof, said grooves intersecting each other at two diametrically opposite points, a semi-circular piston segment positioned in each of said grooves, two diametrically opposite elongated intake recesses within said housing adjacent said spherical surface of said rotor, two diametrically opposite elongated discharge recesses within said housing adjacent said spherical surface of said rotor, each of said discharge recesses being positioned adjacent one of said inlet recesses, all of said recesses extending transversely with respect to said grooves, one of said intake recesses and one of said discharge recesses communicating with each of said grooves, each of said discharge recesses being circumferentially spaced from the adjacent one of said intake recesses, adjacent intake and discharge recesses being disposed on opposite sides of a plane extending between the ends of said segments and along the axis of said rotor, a pair of elongated slides each pivotally connected to a different one of said piston segments and slidably received within a diflerent one of said intake recesses for maintaining said piston segments against rotation with said rotor while permitting lateral oscillation of said piston segments, an intake conduit communicating with each i of said intake recesses centrally of the length thereof, said elongated sIides being of such length that they block said 10 intake conduits. when the ends of said piston segments are in the region of the intersections of said grooves and afiord communication of said intake conduits with said intake recesses during the remainder of each revolution of said rotor.

References Cited in the file of this patent UNITED STATES PATENTS 2,611,534 Kirkpatrick Sept. 23, 1952

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