Orbiting Valve For A Reciprocating Pump
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.
Latest THOMAS INDUSTRIES, INC. Patents:
The present application claims priority from U.S. provisional application 60/610,013 filed Sep. 15, 2004.
FIELDThe 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.
BACKGROUNDPassive 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.
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.
Direct-acting valve systems are known. Cardillo, U.S. Pat. No. 5,058,485, discloses a direct-acting orbiting ring valve for a hydraulic swashplate type pump. White, U.S. Pat. No. 4,877,383, discloses a direct-acting valve such as an orbiting valve for a gerotor device. U.S. Pat. No. 6,224,349 discloses a direct-acting orbiting valve for a swashplate type pump
SUMMARYThe 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.
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.
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.
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.
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.
Referring now to
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.
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.
As can be seen in
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.
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
Now referring more particularly to
In understanding the below description of how
Moving on in the sequence,
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.
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.
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.
Referring to
The orbiting valve 216 shown in
The orbiting valve of
Although the embodiment in
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.
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.
Referring to
Referring to
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
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
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.
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
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, and at least one of said cylinder ports therein an eccentric and an orbit valve, wherein said shalt 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, and wherein said at least one exhaust port or one intake port, and at least one cylinder port are on a same side of the orbit valve.
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 arid 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.
9. 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, and at least one of said cylinder parts 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 polls 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, said orbit valve bas a first surface and an oppositely facing second surface, and only one of said surfaces abuts up against a surface having a port therein.
Type: Application
Filed: Sep 15, 2005
Publication Date: Mar 27, 2008
Applicant: THOMAS INDUSTRIES, INC. (Sheboygan, WI)
Inventors: Roy Rozek (Plymouth, WI), Harry Lynn (Kohler, WI)
Application Number: 11/574,807
International Classification: F04C 27/00 (20060101);