EP1789678A1 - Orbiting valve for a reciprocating pump - Google Patents

Abstract

For pumps, compressors, and air or hydraulic motors with multiple cylinders such as swashplate or nutating type pumps and compressors with axial pistons arranged about a central axis, a orbit valve is connected through an eccentric and bearing to the shaft and caused to orbit around an axis of the shaft by rotation of the shaft. Grooves in the orbit valve surface alternately connect a port in each cylinder with a fixed intake and an exhaust port in the valve plate ties for optimal performance without depending on pressure differential otherwise needed to open and close passive flapper or poppet-type valves. The orbiting motion provides direct acting valve action for intake and exhaust functions with much slower relative motion and far less friction than a rotating valve of similar size.

Description

ORBITING VALVE FOR RECIPROCATING PUMP [0001] The present application claims priority from US provisional application

60/610,013 filed September 15, 2004.

FIELD

[0002] The present invention comprises valves for the porting of intake and exhaust in reciprocating pumps, including vacuum pumps and compressors, and more particularly in multi-cylinder pumps such as swashplate or nutating or wobble-piston type pumps or pumps with axial pistons arranged about a central axis.

BACKGROUND

[0003] Passive valves, such as flapper, poppet or umbrella valves, are used for intake and exhaust porting for reciprocating piston pumps. A flapper valve is typically made of a thin, flat material. Stainless steel has been used for higher pressure flapper valve applications and elastomers have been used for small, low-pressure flapper valve applications. Poppet valves are typically made of a harder material that is biased against a valve plate using a spring. An umbrella valve is usually made of an elastomeric material and includes a built-in attachment method for retaining itself against the valve plate while covering several small holes. Each of these passive valve systems are activated by fluid pressure acting against the valve such that fluid is allowed to pass in one direction only.

[0004] Passive valve systems are limited by the speed at which they can respond and tend to become more restrictive and much less effective at higher speeds.

[0005] Direct-acting valve systems are known. Cardillo, US 5,058,485, discloses a direct-acting orbiting ring valve for a hydraulic swashplate type pump. White, US 4,877,383, discloses a direct-acting valve such as an orbiting valve for a gerotor device. US patent 6,224,349 discloses a direct-acting orbiting valve for a swashplate type pump SUMMARY

[0006] The present invention provides a direct-acting, orbiting valve system for reciprocating piston pumps, including compressors and vacuum pumps, that provides greater pumping efficiency at higher speed ranges than currently feasible with passive valving systems.

[0007] The invention provides both intake and exhaust valve functions using a single orbiting valve member to alternately route the cylinder ports to separate intake and exhaust ports. In addition, a single orbiting valve member can be provided with port routing for separate pressure and vacuum cylinders connected to the same valve plate of a multi-cylinder machine.

[0008] The invention reduces the ultimate torque required and the frictional losses associated with an orbiting valve member by allowing the member to rotate slightly under conditions of stiction creating a twisting motion that results in a mechanical advantage to more easily break away the stiction-adhered surfaces of the orbiting valve and the valve plate as compared to a rotary valve.

[0009] In one embodiment of the invention, routing of intake and exhaust is accomplished by using concentric grooves in the orbiting valve to interconnect cylinder ports in the valve plate with the intake and exhaust ports in the valve plate. In an alternative embodiment the invention provides routing of intake and exhaust with discrete, non- concentric groove segments in the orbiting valve member. In this case the orbiting valve is constrained from rotating by a compliant member.

[0010] The foregoing and other aspects of the invention, such as the inventions features, objects and advantages, are apparent in the brief description of the drawings, detailed description, attached drawings and attached claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a perspective view of a reciprocating pump which embodies the features of one embodiment of the present invention;

[0012] Figure 2 is a side view of the pump shown in Figure 1;

[0013] Figure 3 is a top view of the reciprocating pump shown in Figure 1 ;

[0014] Figure 4 is a bottom view of the reciprocating pump shown in Figure 1 ;

[0015] Figure 5a is a sectional view taken along section line 5-5 of Figure 2;

[0016] Figure 5b is a perspective of the cross section shown in Figure 5a;

[0017] Figure 6a is a perspective view of the orbiting valve of the pump of Figure 1, looking into a face surface of the valve having two concentric grooves therein;

[0018] Figure 6b is a plan view of the orbiting valve's grooved surface shown in Figure 6;

[0019] Figure 7 is a perspective view of the valve plate of the pump of Figure 1, looking into a face surface of the valve plate having three cylinders emanating therefrom; for convenience of illustration the plate has been shown with a squarish shape as opposed to its actual round shape as indicated in Figures 5a, 5b;

[0020] Figure 8 is a perspective view of the valve plate shown in Figure 7, looking into a face surface opposite the surface shown in Figure 7;

[0021] Figure 9 is a face plan view of an assembly of components from the pump of Figure 1, wherein the assembly has a valve plate having three cylinders, an orbiting valve, and an eccentric interfacing the valve plate with the orbit valve; for convenience, the orbit valve circumferential projection seen in Figure 5a is not shown; also for convenience of illustration the valve plate has been shown with a squarish shape as opposed to its actual round shape as indicated in Figures 5a, 5b; wherein the view looks towards the pump's motor end, away from the pump end opposite the motor, and into the face surface of the valve plate having the cylinders emanating therefrom;

[0022] Figures 1 Oa-I Oe are plan views generally the same as shown in Figure 9, except for further convenience, only one cylinder and its associated cylinder port are shown; the Figures show the orbiting valve's sequence relative to stated positions of the piston;

[0023] Figure 11 is a partial cross sectional view taken along a longitudinal axis of a pump having an alternative embodiment of the invention , wherein the pump has its orbit valve eccentric on the opposite side of the valve plate as compared to the placement of the orbit valve in Figure 5 a;

[0024] Figure 12a is a face plan view of an assembly of components from a pump of the type shown in Figure 1 ; the view shows an alternative embodiment of the invention, wherein the assembly has a multi cylinder valve plate, for convenience, only one cylinder is shown; an orbiting valve having multiple segmented intake through ports and multiple segmented exhaust grooves, again for convenience, only one exhaust segment is shown; and an eccentric interfacing the valve plate with the orbiting valve, wherein the view looks towards the pump's motor end, away from the pump end opposite the motor, and into the face surface of the valve plate having the cylinders emanating therefrom;

[0025] Fig 12b is a perspective view of the assembly shown in Figure 12a; for convenience, the arms shown emanating from the orbiting valve in this perspective view were omitted from the plan view in Figure 12a;

[0026] Figures. 13 is a top perspective view of the orbiting valve eccentric of the pump of Figure 1;

[0027] Figure 14 is an end perspective view of the shaft, orbiting valve eccentric and orbiting valve of Figure 1 assembled together.

DETAILED DESCRIPTION [0028] Referring now to Figures l-5b, nutating or wobble-piston type compressor or pump 100 has a housing 102. The housing 102 encloses a crank case volume 104. The pump has certain main drive components in the housing. The main drive components in the housing include shaft 18, eccentric 64, eccentric bearing 62, wobble member 60, and cross- type universal joint 56. Universal joint 56 has two of its opposed arms journalled or coupled to connector 59 and the other two of its opposed arms journalled or coupled to wobble or yoke member 60.

[0029] The wobble member 60 has three arms 74 all of which are the same as each other. Only one arm 74 is shown. Each arm has, at its end, a ball head 76.

[0030] Pump 100 has three pistons, all of which are the same. Only one piston 14a, 14b is fully shown. Each piston has a piston head 14b and piston rod 14a. Each piston rod 14a is hollow and contains a socket halve 78. Each wobble member's ball head 76 is coupled to a piston rod 14a via the socket half 78.

[0031] As can be seen in Figures 7 and 9, each piston is associated with a respective cylinder 20a, 20b and 20c. Each cylinder has associated with it a cylinder port 28a, 28b and 28c. See Figures 7, 8 and 9. The cylinder ports 28a, 28b, 28c each comprise elongated cylinder groove port portions 28a", 28b", 28c" and small centrally located oval cylinder through port portions 28a', 28b', 28c'. The small oval portions are the only portions of the cylinder ports that actually pass through the valve plate. The center of UV joint 56 is aligned along the center the shaft axis 18a.

[0032] During operation of pump 100 drive shaft 18 is rotated by the motor 58 , the stator of which is affixed to the end cover 52, which is affixed, via wall 103, to housing 102 to enclose orbiting valve 16, orbiting valve eccentric 30, orbiting valve eccentric bearing 32 and counter moment mass 54. [0033] As the motor shaft 18 rotates, eccentric 64, through bearing 62, causes wobble member 60 to wobble and thereby drive rod 14a in a predominantly reciprocating motion. Orbiting valve eccentric 30, acting through orbiting valve eccentric bearing 32, causes orbiting valve 16 to orbit about the shaft centerline 18 as it slides relative to the valve plate 25. Two concentric grooves 22 and 24, in the orbiting valve 16, alternately slide over the cylinder ports 28a, 28b and 28c to provide sequenced fluid communication with intake port 27 and exhaust port 26. See Fig. 9, 1Oa-IOe. Groove 22 can be described as a pressure or exhaust groove and groove 24 can be described as an intake groove. The dashed line in Figures. 5a, 5b. indicates fluid communication between exhaust port 26 shown in Fig. 9 and connector tube 46 shown in Fig. 5 a. Fluid intake is routed through port 44 of the attenuation chamber 48 , through ports 42 into the crankcase chamber 104 and then through valve intake port 27. The arrows in Fig. 5a, 5b show the fluid flow direction.

[0034] Fig. 5a and Fig. 5b show piston rod 14a in a top dead center position such that cylinder through port 28a is no longer connected to exhaust groove 22 or intake groove 24.

[0035] Now referring more particularly to Figures 10a- 1Oe, the orbiting valve sequence can be further seen. In these Figures, for ease of reference, only one cylinder 20a and its associated cylinder port 28a are shown. Also, for ease of reference, the projection 16c is not shown. Each of the other cylinders 20b, 20c are going through exactly the same sequence except the cylinders are 120° out of phase with each other. Looking into the valve plate 16 from the cylinder side, the direction of orbit valve 16 is indicated by arrow 70 and is counterclockwise. The angular orientation of the shaft 18 relative to orbit valve 16 during the sequence is marked by darkened area 30a. The degrees of rotation can thus be correlated to the piston's position.

[0036] In understanding the below description of how Figures 10a- 1Oe, depict the orbit valve's sequencing, it is important to note that the orbiting valve being sequenced by eccentric 30, relative to the piston, is phased to be 90° out of phase with the motion of the pistons. At the start of the sequence, Fig. 10a, the piston is at the top dead center (TDC) position, see Fig. 5a and 5b. The cylinder port 28a is not in communication with either the exhaust or pressure groove 22 or the intake groove 24. The intake groove 24 is ready to communicate with the cylinder port 28a. In Fig.. 10a the center 16a of orbiting valve 16 is shown displaced to the left. The direction of displacement, if an "x, y" graph 17, oriented about shaft 18's center line, were superimposed over Figure 10a, would be "-x". The amount of displacement is determined by the offset 30b (Fig. 13) of the orbiting valve eccentric 30 from shaft centerline 18a. The center 16a of orbit valve 16 is not displaced along the y axis when rod 14a is in the top dead center position. The orbit valve center 16a is thus centered vertically with respect to shaft 18. In the top dead center position, the orbiting valve center 16a is located predominantly 90 degrees counterclockwise from the top cylinder 20a shown in Fig. 10a.

[0037] Moving on in the sequence, Fig. 10b, the piston has traveled halfway down (away from valve plate 25) the cylinder 20a. Cylinder through groove 28a" is in communication with intake groove 24. Next, Fig. 1OC, the piston has traveled to bottom dead center ( BDC ), a maximum distance from valve plate 25. Cylinder port 28a is not in communication with either the intake 24 or pressure groove 22. As the piston moves from BDC position, to a position approximately at the center of the upward stroke, the cylinder through port 228a' is not in communication with either intake nor exhaust groove. This allows the pressure to build up within the cylinder to a level nearly equal to that pressure in the exhaust groove. Next, Fig. 1Od, the piston has traveled midway up the cylinder, i.e., at middle of upstroke and point of maximum compression. Finally, in Fig. 1Oe, the piston is 45° before TDC. The cylinder port 28a, by way of cylinder groove portion 28a", is open to the exhaust or pressure groove 22. The relative position of the other ports 28b, 28c, when the piston is 45° before TDC , can be seen in Figure 9.

[0038] In the above described sequence, the orbit valve 16 is not restrained from rotation about its own axis, but since the grooves 22 and 24 are circular the orbit valve can rotate as well as orbit, although the rotation about its own axis does not affect its operation. In addition, the combination of bearing 32 and the friction of the orbit valve 16 against the valve plate 25 would result in the motion being largely orbital with only little, if any, rotation. Further the grooves 22 and 24 do not pass through the orbit valve to form a through space.

[0039] The use of a cylinder port with a grooved portion 28a" and a through portion 28a' is believed to be advantageous over the use of a simple through port. Also, having the inner groove 22 as the exhaust groove 22 , as opposed to the outer groove, is believed to be advantageous in that the surface area forming the inner groove is less than the outer groove. The smaller area reduces the forces on the orbit valve 16 resulting from the fluid pressure. The orbiting valve 16, however, could be configured with the outer groove as the exhaust groove.

[0040] A further feature that can be included in a pump embodying the invention is an axial spring bias force 86 that may be provided between the orbiting valve 16 and a stationary structure attached to the housing, such as end cover 52. The spring serves to overcome the net separation forces caused by the difference between (1) the fluid pressure acting on an area of the surface of the orbiting valve 16 contacting the valve plate 25 and (2) the fluid pressure acting on the surface of the orbit valve opposite the orbit valves sealing surface. The spring assures sealing between the land areas surrounding the grooves 22, 24 and the valve plate 25 of housing 102. Alternatively, one or more axially extending springs could provide a biasing force between the orbiting valve 16 and eccentric 30. To improve biasing of the orbit valve, a circumferential projection 16c is provided on the valve's end wall surface opposite the valve surface having the concentric grooves. The circumferential projection defines a space to receive an end coil of spring 86. The projection of course does not have to be continuous. As an alternative to a projection, a groove can be provided to receive an end coil of the spring. For convenience, the spring 86 is not shown in its actual relative coiled and flexed state.

[0041] Referring to Figures 12a and 12b, an alternative embodiment having a segmented orbit valve with a combination of grooved segments and through segments is shown. The associated valve plate 225, would have 3 cylinders, for convenience only one cylinder 220a is shown. The valve plate would have three cylinder ports, again for convenience only, port 228a, comprising groove portion 228a" and through portion 228a' is shown. The valve plate further has three exhaust ports; for convenience only one 226a is shown.

[0042] The orbiting valve 216 shown in Figures 12b and 12a has three intake segments 224a, 224b, 224c; each would be uniquely associated with one of the three cylinders. In the shown embodiment intake 224a is associated with cylinder 220a. The intake segments completely pass through the orbit valve. Having the intake segments as through apertures, allows for direct intake into the associated cylinder port, thus eliminating the need for any intake ports in the valve plate.

[0043] The orbiting valve of Figures 12a and 12b would also have three grooved segmented exhaust ports; for convenience only exhaust port 222a is shown. Each exhaust port segment is uniquely associated with a cylinder and a cylinder port. In the shown embodiment grooved exhaust segment 226a is associated with cylinder port 228a and cylinder 220a. The exhaust segments do not pass through the orbit valve. The orbit valve would have a projection similar to the projection 16c shown in Figures 5a,5b. For convenience, the projection is not shown in Figures 12a, 12b. [0044] Although the embodiment in Figures 12a and 12b show their intake segment as passing through the orbit valve; they do not have to pass through the orbit valve. In this case, proper intake porting through the valve plate would have to be provided. Further, in this case, it would be possible to have the exhaust segments as pass through holes thereby eliminating the need for exhaust ports in the valve plate. In this case, the cavity in which the orbit valve is enclosed would have to be pressure sealed. The pressure allowed to build up in the cavity could be made sufficient to overcome the net separation forces between the valve plate and orbit valve so as to eliminate the need for an external biasing force member such as spring 86. The amount of pressure allowed to act as the biasing force should not be so great as to create undue friction forces between the orbit valve and valve plate. The pressure could be regulated by a pressure regulation port in the cavity or some or some other pressure regulator.

[0045] The orbit valve 216 must be prevented from rotating relative to the housing by use of any of several possible methods including but not limited to an Oldham coupling, one or more idler crank mechanisms, one or more torsional springs, one or more leaf springs, or other compliant mechanisms either separately attached between the disk and the stationary housing or integrated as a monolithic member with the disk itself. For convenience, shown only in the perspective view 12b, are four integral flexible compliant arms 216d.

[0046] A spring and projection similar to spring 86 and projection 16c could also be used to form a resilient compliant. In this case, the projection used to receive an end coil of the spring would be sized so that the circumferential projection forms a cavity which permits the end coil to snap-fit into the cavity. The snap-fit would serve to couple the spring to the orbit valve with a sufficient frictional fit to resist the torsion forces imparted to the orbit valve by the eccentric. If a groove were used to receive the spring, the groove could have a cavity therein to receive a spring end and thereby limit the orbit valves rotation. [0047] Referring to Figures 12a, 12b, orbit valve 216 could be used with a pump having compression and vacuum cylinders. The cylinders would be a combination of compression and vacuum cylinders. Each cylinder would be associated with a combination of orbit valve intake/exhaust cavities, which could be combinations of grooves, or through ports. The valve plate and orbit valve would be configured to interconnect the pressure and vacuum cylinders provided within the same pump to the appropriate intake or exhaust ports in the valve plate to sequence and to provide both vacuum and pressure pumping capability with separate fluid circuits; or to provide a combination of pumping and motoring using either a pressure or vacuum fluid source and/or an electric motor in any combination.

[0048] Referring to Figure 13 the eccentric 30 could include a portion ( not shown) that acts as a counter weight to dynamically balance the primary radial dynamic forces created by the orbiting motion of the orbit valve 16. In this case counter moment mass 54 would contain a counter moment mass to dynamically balance both the primary drive mechanism unbalance moment of the pump or motor and the unbalance moment created by the orbit valve and its eccentric counter mass being located in two different axial planes.

[0049] In still another aspect of the invention, the orbit valve eccentric 330 may be on the same side of valve plate 325 as the eccentric 64. See Fig. 11. In this case, the eccentric 330 is coupled directly to eccentric 64. Eccentric 64 imparts an orbiting motion to eccentric 330 by way of eccentric bearings 332. Eccentric 330 imports an orbiting motion to orbit valve 316 with coupling 300.

[0050] Although the orbit valve cavities 22, 24 have been described as grooves 22, 24, they can also be passages, channels or ducts. Additionally, although both 22 and 24 are described as grooves, they could comprise a combination of grooves and pass through apertures. In this case the porting of the valve plate would follow the principles described with regards to Figures 12a, 12b. The orbit valve can have a variety of shapes beyond those shown or described. The valve plate and housing can also have a variety of shapes beyond those disclosed.

[0051] It should be noted that the term coupling is used inclusively herein to cover both direct and indirect coupling. For instance the shaft 18 is coupled to the wobble member 60 by way of an indirect coupling. The shaft is also coupled to the piston 14a, 14b by way of an indirect coupling.

[0052] Varying embodiments of the invention have been described in considerable detail. Many modifications and variations to the embodiments described will be apparent to a person of ordinary skill in the art. Therefore, the invention should not be limited to the embodiments described.

Claims

CLAIMSWhat is claimed is,

1. In a reciprocating pump, compressor, air motor or hydraulic motor having multiple cylinders, multiple cylinder ports, multiple pistons, a rotatable shaft, a housing having at least one exhaust port and one intake port therein, a partition having at least one exhaust port or one intake port therein, an eccentric and an orbit valve, wherein said shaft is coupled to said eccentric, and said eccentric is coupled to said orbit valve, said orbit valve comprising:

a plurality of cavities therein;

a first fluid porting position in which a first cavity of said plurality of cavities is in fluid communication with a first one of said cylinder ports from said plurality of cylinder ports, said first cavity also in fluid communication with said at least one intake or exhaust port in said partition, a second cavity from said plurality of cavities obstructed from fluidly communicating with said first cylinder port and obstructed from fluidly communicating with said at least one intake or exhaust port in said partition;

a second fluid porting position wherein a second cavity from said plurality of cavities is in fluid communication with said first cylinder port, said first cavity obstructed from fluid communication with said first cylinder port, said second cavity in fluid communication with either said exhaust port or intake port in said housing; said second cavity obstructed from fluid communication with said at least one exhaust or intake port in said partition; and

wherein said orbit valve moves from said first fluid porting position to said second fluid porting position along an orbit path, during rotation of said shaft.

2. The pump, compressor, air motor or hydraulic motor of claim 1 wherein said orbit valve further comprises a first facing surface and a second facing surface oppositely oriented from said first facing surface; and

wherein said second cavity extends into said first facing surface without passing through said second facing surface.

3. Wherein said orbit valve further comprises:

a first facing surface and an oppositely oriented second facing surface; and

wherein said second cavity extends into said first facing surface and passes through said second facing surface to provide a through aperture passing through said orbit valve.

4. A reciprocating pump, compressor, air motor or hydraulic motor having multiple pistons that reciprocate in cylinders arranged about a center axis, and a wall having at least one port per cylinder that communicates with a volume of the cylinder that is varied by the reciprocation of the piston in the cylinder, the improvement comprising:

an orbit valve rotatably connected to an eccentric on the central drive shaft for substantially orbiting about the center axis, the orbit valve having cavities in a side of the valve that faces the wall, the wall has at least one intake port between two cylinders that communicates with the cylinder ports through at least one of the cavities in the valve, and at least one exhaust port between two cylinders to provide intake and exhaust of fluid in timed sequence with the stroke of the pistons as the cavities pass over the appropriate cylinder port and the intake or exhaust ports as the valve orbits against the wall.

5. The improvement of claim 4, wherein the cavities are annular grooves located concentrically with respect to each other and centered about the center axis of the valve and the valve is free to rotate without its angular orientation affecting the interconnections of the cylinder ports with the appropriate intake and exhaust ports.

6. The improvement of claim 4, wherein the cavities are predominately segments of an arc and have a discrete length for interconnecting between specific cylinder ports and specific intake and exhaust ports and the disk is inhibited from rotating relative to the pump or motor housing by use of a resilient member.

7. The improvement of claim 1, wherein an axial spring bias force is provided between the orbiting valve and the housing.

8. The improvement of claim 4, wherein a sufficient number of cavities and ports are provided to interconnect a combination of pressure and vacuum cylinders provided within the same pump or motor.