WO1998006933A1

WO1998006933A1 - Rotary piston machine

Info

Publication number: WO1998006933A1
Application number: PCT/US1997/013930
Authority: WO
Inventors: Batista Eduardo Quincoces
Original assignee: Cordero, Medina, Auracelis
Priority date: 1996-08-09
Filing date: 1997-08-07
Publication date: 1998-02-19
Also published as: AU3912197A

Abstract

A universal rotary fluid machine (10) adaptable for use as a pump, a compressor, an expander, and an internal combustion engine. The fluid machine includes a piston rotor (18) having a vane (50) projecting therefrom. The piston rotor revolves within a chamber (14) with the vane spanning the gap between the piston rotor and the wall of the chamber. The chamber is provided with an inlet (58) and an outlet (60). The piston rotor in cooperation with a gate rotor (22), divides the chamber into two volumes. The gate rotor has a cutout (52) to accommodate the vane when the vane sweeps through the gate rotor space. The first volume contracts as the vane rotates toward the outlet while the second volume, located between the inlet and the vane, expands. The fluid machine further includes a network of spring loaded sealing strips (148, 150, 152, 192, 194), provided on the piston and the gate rotors, which prevent fluid leakage around the piston and gate rotors. A lubrication system (198, 200, 202, 204) for the fluid machine is also disclosed.

Description

ROTARY PISTON MACHINE

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates to a machine in which a rotary piston in continuous rotational motion is used to move, or is moved by, a fluid.

2. DESCRIPTION OF THE PRIOR ART

Fluid machines are devices which impart shaft work to, or derive shaft work from fluids. The fluids may be chemically reacting mixtures or non-reacting fluids. The term "fluid machine" generally encompasses three categories of equipment that have an extremely wide range of industrial applicability. The three categories are pumps and compressors, expanders and turbines, and internal combustion engines. Depending on the operating conditions and the types of ancillary equipment provided, essentially the same fluid machine can be used in all three categories .

For example, consider the well known reciprocating piston housed in a cylinder and linked to an eccentric crankshaft. The piston and cylinder arrangement is commonly used as a positive displacement pump or compressor, as an expander in the form of the steam engine, and as an internal combustion engine in the form of the common gasoline and diesel engines. As applied in each of the three categories, the piston and cylinder arrangement essentially only varies in the types of ancillary equipment, such as ignition systems, fuel supply systems, valve gear, etc., associated with it. Similarly, the present invention is a general purpose fluid machine applicable in all the three categories enumerated above with minor modifications. The present invention uses a rotary piston (which is also referred to herein as a piston rotor) , rotating in a synchronized manner with a gate rotor, to exchange momentum with a fluid. Although many types of rotary piston fluid machines are known in the prior art, none of the prior art rotary piston machines show the unique structure of the present invention.

U.S. Patent Number 836,768, issued to Elmer G. Kesling on November 27, 1906, shows a rotary engine having a rotor with three blades. The blades slide in and out relative to the rotor body as the rotor goes through each revolution. The Kesling engine does not have a piston rotor rotating in synchrony with a gate rotor. Further, Kesling does not show the network of spring loaded sealing strips which form part of the present invention. U.S. Patent Number 942,476, issued to William W. heeler on December 7, 1909, shows a rotary engine having piston rotors and a gate rotor. The projections on the piston and gate rotors are provided with sealing strips that sealingly abut the peripheral wall of the chamber housing the rotors. Wheeler does not show circular sealing strips that seal the gaps between the ends of the rotors and the end plates of the chamber housing the rotors.

U.S. Patent Number 980,402, issued to William Birrell et al . on January 3, 1911, shows a rotary engine having a rotor with a blade which slidably moves relative to the rotor body as the rotor goes through each revolution. Birrell et al . do not show a piston rotor rotating in synchrony with a gate rotor. Further, Birrell et al . do not show the network of spring loaded sealing strips which form part of the present invention.

U.S. Patent Number 1,016,199, issued to William Arthur Beard on January 30, 1912, shows a rotary pump having a piston rotor and a gate rotor. The piston rotor has two vanes projecting therefrom. The vanes mesh with cutouts formed in the gate rotor. Beard does not show the network of spring loaded sealing strips which form part of the present invention. U.S. Patent Number 1,037,455, issued to Victor J. Diefenderfer on September 3, 1912, shows an air compressor havincj two piston rotors and a gate rotor. The vanes projecting from the piston rotors are provided with sealing strips that sealingly abut the peripheral wall of the chamber housing the piston rotors . Also, the gate rotor of Diefenderfer has sealing strips that sealingly abut the peripheral wall of the chamber housing the gate rotor. Diefenderfer does not show circular sealing strips that seal the gaps between the ends of the rotors and the end plates of the chamber housing the rotors .

U.S. Patent Number 1,042,994, issued to James G. Wilson on October 29, 1912, shows a rotary engine having radially sliding vanes carried by the rotor. Spring biased packing rings seal any gaps between the rotor and the housing. Wilson '994 does not show a piston rotor rotating in synchrony with a gate rotor. Further, Wilson ' 994 does not show the network of spring loaded sealing strips which form part of the present invention. U.S. Patent Number 1,531,470, issued to James G. Wilson on March 31, 1925, shows a rotary internal combustion engine having radially sliding vanes carried by the rotor. Spring biased sealing strips project from the edges of the vanes to seal any gaps between the vanes and the interior surface of the housing. Wilson '470 does not show a piston rotor rotating in synchrony with a gate rotor. Further, Wilson '470 does not show the network of spring loaded sealing strips which form part of the present invention.

U.S. Patent Number 1,953,695, issued to Hellmuth Walter on April 3, 1934, shows a rotary fluid machine where pumping is achieved by the synchronized rotation of a piston rotor and a gate rotor. Walter does not show the network of spring loaded sealing strips which form part of the present invention.

U.S. Patent Number 2,497,373, issued to Albert Z. Richards, Jr. on February 14, 1950, shows a rotary pump having two piston rotors and one gate rotor. Each piston rotor has two vanes projecting therefrom. The vanes mesh with cutouts formed in the gate rotor. Richards, Jr. does not show the network of spring loaded sealing strips which form part of the present invention. U.S. Patent Number 3,483,825, issued to Leroy A. Difford et al . on December 16, 1969, shows a gear pump wherein the gear teeth are provided with tungsten carbide inserts which extend along the edges and sides of the gear teeth. Difford et al. do not show a piston rotor rotating in synchrony with a gate rotor. Further, Difford et al . do not show the network of spring loaded sealing strips which form part of the present invention.

U.S. Patent Number 3,701,254, issued to Oscar Michejda on October 31, 1972, shows a rotary engine having multiple piston rotors and one gate rotor. Each piston rotor has a vane projecting therefrom. The vanes mesh with a cutout formed in the gate rotor. Michejda does not show the network of spring loaded sealing strips which form part of the present invention. U.S. Patent Number 3,820,798, issued to Heinz Lamm on June 28, 1974, shows a sealing strip for a rotary piston internal combustion engine. Lamm does not show a piston rotor rotating in synchrony with a gate rotor. Further, Lamm does not show the network of spring loaded sealing strips which form part of the present invention.

U.S. Patent Number 3,909,015, issued to Gozo Kasahara on September 30, 1975, shows a ring seal assembly for a rotary piston internal combustion engine. Kasahara does not show a piston rotor rotating in synchrony with a gate rotor. Further, Kasahara does not show the network of spring loaded sealing strips which form part of the present invention.

U.S. Patent Number 3,931,977, issued to Alexander Goloff on January 13, 1976, shows a seal assembly for a rotary piston internal combustion engine. Goloff does not show a piston rotor rotating in synchrony with a gate rotor. Further, Goloff does not show the network of spring loaded sealing strips which form part of the present invention.

U.S. Patent Number 3,973,882, issued to Frank J. Winchell on August 10, 1976, shows a seal arrangement for the apices of the piston of a rotary piston internal combustion engine. Winchell does not show a piston rotor rotating in synchrony with a gate rotor. Further, Winchell does not show the network of spring loaded sealing strips which form part of the present invention. U.S. Patent Number 3,989,425, issued to Donald F. Walker et al . on November 2, 1976, shows a seal biasing spring for a rotary piston internal combustion engine. Walker et al . do not show a piston rotor rotating in synchrony with a gate rotor. Further, Walker et al . do not show the network of spring loaded sealing strips which form part of the present invention. U.S. Patent Number 4,007,715, issued to Robert Peter Bonnell et al. on February 15, 1977, shows a rotary engine having twc piston rotors and a gate rotor. The piston rotors have vanes that alternatingly mesh with a cutout in the gate rotor. Bonnell et al . do not show the network of spring loaded sealing strips which form part of the present invention.

U.S. Patent Number 4,058,321, issued to Michael T. Gavrun et al. on November 15, 1977, shows an oil seal for the face of the rotor of a rotary piston internal combustion engine. Gavrun et al. do not show a piston rotor rotating in synchrony with a gate rotor. Further, Gavrun et al . do not show the network of spring loaded sealing strips which form part of the present invention. U.S. Patent Number 4,312,629, issued to Emmanouil A. Pelekis on January 26, 1982, shows a rotary fluid machine having a piston rotor and a gate rotor. The piston rotor has a vane that meshes with a cutout in the gate rotor. Pelekis does not show the network of spring loaded sealing strips which form part of the present invention. U.S. Patent Number 4,437,822, issued to Jeremy Schwartz et al . on March 20, 1984, shows a radial sealing assembly for use with the rotor of a Wankel-type engine. Schwartz et al . do not show a piston rotor rotating in synchrony with a gate rotor. Further, Schwartz et al . do not show the network of spring loaded sealing strips which form part of the present invention.

Swiss Patent Document Number 195407, by JUNKER & FERBER, VORM. NOVA-WERKE A.G. dated April 16, 1938, shows a biasing assembly for biasing a piston ring. Swiss document '407 does not show a piston rotor rotating in synchrony with a gate rotor. Further, Swiss document '407 does not show the network of spring loaded sealing strips which form part of the present invention.

French Patent Document Number 1,386,016, by GEOTZEWERKE FRIEDRICH GOETZE A.G. dated May 7, 1965, shows a piston seal for a rotary piston engine. French document '016 does not show a piston rotor rotating in synchrony with a gate rotor. Further, French document '016 does not show the network of spring loaded sealing strips which form part of the present invention.

German Patent Document Number 1,196,452, by Walter Froede dated July 8, 1965, shows a leaf spring system for pushing the piston seal against the interior wall of the combustion chamber of a rotary engine. Froede does not show a piston rotor rotating in synchrony with a gate rotor. Further, Froede does not show the network of spring loaded sealing strips which form part of the present invention.

German Patent Document Number 1,201,137, by Eugen W. Huber et al. dated September 16, 1965, shows a corner seal for the rotor of a Wankel-type engine. Huber et al . do not show a piston rotor rotating in synchrony with a gate rotor. Further, Huber et al . do not show the network of spring loaded sealing strips which form part of the present invention.

German Patent Document Number 1,245,636, by Hermann Baumler dated July 27 1967, shows a leaf spring system for pushing the piston seal against the interior wall of the combustion chamber of a rotary engine. German document '636 does not show a piston rotor rotating in synchrony with a gate rotor. Further, German document '636 does not show the network of spring loaded sealing strips which form part of the present invention.

None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.

SUMMARY OF THE INVENTION

The present invention is a universal rotary fluid machine. The rotary fluid machine of the present invention is referred to as "universal", because the fluid machine can be adapted to operate as a pump, a compressor, an expander or turbine, and an internal combustion engine. The rotary fluid machine of the present invention includes a housing having a figure eight shaped chamber therein. The figure eight shaped chamber has a first lobe which houses a piston rotor, and a second lobe which houses a gate rotor. The piston and gate rotors are mounted on shafts journaled within the housing, such that the piston and the gate rotors can rotate within their respective lobes. The rotation of the piston and gate rotors are synchronized by a pair of intermeshing gears, one gear being fixed to the shaft upon which the piston rotor is mounted and the other gear being fixed to the shaft upon which the gate rotor is mounted. Power can be applied to either shaft when using the fluid machine as a pump or compressor, and power can be derived from either shaft when using the fluid machine as an engine or an expander .

The piston rotor has a cylindrical portion which is concentric with the piston rotor shaft. This cylindrical portion is smaller in diameter than the first lobe housing the piston rotor. A vane, extending along the length of the cylindrical portion of the piston rotor, projects radially from the outer surface of the cylindrical portion of the piston rotor. The vane spans the gap between the cylindrical portion of the piston rotor and the peripheral wall of the lobe housing the piston rotor.

The gate rotor is essentially cylindrical with a trough or cutout along its length. The gate rotor has a diameter that is substantially the same as the diameter of the lobe housing the gate rotor. Also, the diameter of the gate rotor is such that it continuously contacts the outer surface of the cylindrical portion of the piston rotor except when the vane of the piston rotor sweeps through portions of the volume swept by the gate rotor. The rotation of the piston and gate rotors are synchronized such that the cutout in the gate rotor momentarily accommodates the vane as the vane of the piston rotor sweeps through portions of the volume swept by the gate rotor. Thus the vane of the piston rotor is prevented from catastrophically colliding with the gate rotor.

The figure eight chamber is formed by two overlapping cylindrical volumes, one volume corresponding to the first lobe housing the piston rotor and the other volume corresponding to the second lobe housing the gate rotor. Where the surfaces of the cylindrical volumes intersect, two cusps are formed on either side of the figure eight chamber. Inlet and outlet openings are provided in the wall of the lobe housing the piston rotor, the inlet opening being located proximate a first one of the cusps and the outlet opening being located proximate the second cusp . The portion of the machine cycle during which the vane is sweeping past the inlet opening and the outlet opening, and during which the vane sweeps through portions of the volume swept by the gate rotor, is referred to herein as the transition period. The portion of the machine cycle during which the vane is sweeping over the inner surface of the wall of the lobe housing the piston rotor, is referred to herein as the working period.

During the working period, the gate rotor abuts the outer surface of the cylindrical portion of the piston rotor thereby preventing fluid flow around the side of the cylindrical portion of the piston rotor adjacent to the gate rotor. Also during the working period, the vane substantially seals the gap between the cylindrical portion of the piston rotor and the peripheral wall of the lobe housing the piston rotor. Thus, during the working period, the vane divides the working volume within the figure eight chamber into two volumes. The first volume is referred to as the leading control volume, which extends between the vane and the outlet opening (i.e. the volume located ahead of the vane) along the direction of rotation of the piston rotor toward the outlet opening. The second volume is referred to as the lagging control volume, which extends between the inlet opening and the vane (i.e. the volume located behind the vane) along the direction of rotation of the piston rotor as it rotates toward the outlet opening. The working volume refers to the portion of the volume of the figure eight chamber not occupied by the piston and gate rotors .

Therefore, during the working period, the leading control volume contracts while the lagging control volume expands as the vane moves away from the inlet and toward the outlet. Thus fluid is ejected from the leading control volume, through the outlet opening, while the lagging control volume is filled by fluid drawn through the inlet opening. Just as the vane reaches the rim of the outlet opening, a valve of an appropriate type provided downstream of the outlet closes in order to prevent unrestricted fluid communication between the inlet and outlet openings. This vane position also marks the beginning of the transition period. The transition period ends once the vane passes the inlet opening and just reaches the portion of the wall of the first lobe, housing the piston rotor, which extends between the inlet and the outlet openings. The valve now opens and the process is repeated resulting in continuous pumping of the fluid.

To enable the moving parts of the fluid machine to move freely, some clearance between the walls of the figure eight. chamber and the piston and the gate rotors is necessary. However, this clearance can lead to leakage, around the piston and the gate rotors, which will reduce the pumping efficiency of the fluid machine. A network of spring loaded sealing strips are provided on the piston and the gate rotors to increase efficiency as much as possible. Also disclosed is a lubricating system for lubricating the piston and the gate rotors.

In addition, various arrangements of multiple piston and/or gate rotors, either in the same machine block or in separate machine blocks, are disclosed for use in a variety of fluid handling and prime mover applications.

Accordingly, it is a principal object of the invention to provide a rotary piston fluid machine which has universal applicability as a pump, a compressor, an expander or turbine, an internal combustion engine, etc.

It is another object of the invention to provide a rotary piston fluid machine having a piston rotor and a gate rotor, wherein the piston and the gate rotor each have a network of sealing strips to reduce leakage around the rotors. It is a further object of the invention to provide a rotary piston fluid machine having a piston rotor and a gate rotor, wherein a lubricating system is provided for lubricating the piston and the gate rotors.

Still another object of the invention is to provide a rotary piston fluid machine having a piston rotor, provided with a vane, rotating in cooperation with a gate rotor having a cutout to accommodate the vane .

It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.

These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an exploded perspective view of the rotary piston fluid machine of the present invention.

Fig. 2 is an isolated perspective view of the piston rotor of the rotary piston fluid machine of the present invention.

Fig. 3 is an isolated perspective view of the gate rotor of the rotary piston fluid machine of the present invention.

Fig. 4A is an exploded perspective view showing the various kinds of sealing strips used on the piston and the gate rotors of the rotary piston fluid machine of the present invention.

Fig. 4B is an isolated detail view showing the sliding contacts of the longitudinal sealing strips used on the piston and the gate rotors of the rotary piston fluid machine of the present invention. Fig. 5 is an end view of the rotary piston fluid machine of the present invention showing the piston and gate rotors disposed within the figure eight chamber.

Fig. 6 is a perspective view of the rotary piston fluid machine of the present invention partially broken away to show the piston and gate rotors disposed within the figure eight chamber.

Fig. 7A is an isolated perspective view of the piston rotor of an alternative embodiment of the rotary piston fluid machine of the present invention wherein the piston rotor acts as a valve.

Fig. 7B is an isolated interior perspective view of an end plate of an alternative embodiment of the rotary piston fluid machine of the present invention wherein the piston rotor acts as a valve .

Fig. 7C is an isolated exterior perspective view of an end plate of an alternative embodiment of the rotary piston fluid machine of the present invention wherein the piston rotor acts as a valve .

Figs. 8A-8F are a sequence of views showing the relative positions of the piston and gate rotors at various points in time during the operating cycle of the rotary piston fluid machine of the present invention. Fig. 9 is a cross sectional view showing the lubricant passages of the lubrication system of the rotary piston fluid machine of the present invention.

Fig. 10 is an exploded view of the rotary transfer valve usable with the rotary piston fluid machine of the present invention.

Figs. 11A-11D are a series of views showing various multiple piston rotor and/or multiple gate rotor configurations obtainable with the rotary piston fluid machine of the present invention. Fig. 12 is a schematic view showing an internal combustion engine using a pair of the rotary piston fluid machines of the present invention.

Fig. 13 is an end view showing the lubricant collection cavity of the lubrication system of the rotary piston fluid machine of the present invention.

Fig. 14 is an isolated fragmentary perspective view of the piston rotor of the rotary piston fluid machine of the present invention showing the longitudinal sealing strip grooves and the springs for biasing the longitudinal sealing strips. Fig. 15 is an isolated fragmentary perspective view of the piston rotor of the rotary piston fluid machine of the present invention showing the end sealing strip grooves and the springs for biasing the end sealing strips.

Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a rotary piston fluid machine that can be made in a variety of configurations depending on the intended application. The operational principles of the present invention will first be described with reference to the basic configuration illustrated in Figs. 1-3, 5, 6, and 8A-8F. The basic configuration illustrated in Figs. 1-3, 5, 6, and 8A-8F, can be employed as a pump, a hydraulic motor, a gas compressor, an expansion engine, a vacuum pump, and an internal combustion engine. However, for the purpose of clarity of the presentation, the operation of the basic configuration- -referred to herein as a fluid machine 10- -will be described in the context of its use as a compressor.

The fluid machine 10 includes a housing or machine block 12. The block 12 has a figure eight shaped chamber 14 therein. The figure eight shaped chamber has a first lobe or compartment 16 which houses a piston rotor 18, and a second lobe or compartment. 20 which houses a gate rotor 22. The piston rotor 18 and the gate rotor 22 are mounted on shafts 24 and 26, respectively, which are rotatably supported by cooperating end plates 28 and 30. The end plates 28 and 30 are bolted to respective ends of the housing 12 and act as closures for the figure eight chamber 14. Gasket 29 seals any gaps between the end plate 28 and the side of the housing 12 proximate to the end plate 28, while gasket 31 seals any gaps between the end plate 30 and the side of the housing 12 proximate to the end plate 30. The plate 28 is provided with a pair of holes 32 and 34, and the plate 30 is provided with a pair of holes 36 and 38. Holes 32 and 36 support the piston rotor shaft 24, and holes 34 and 38 support the gate rotor shaft 26. Each of the holes 32, 34, 36, and 38 is provided with a seal 40 and a set of roller bearings 42. The seals 40 seal any gaps around the shafts 24 and 26 to prevent any undesired fluid communication between the figure eight chamber 14 and the atmosphere, otherwise leakage around the shafts 24 and 26 will lead to loss of suction and/or vacuum thus detrimentally affecting the efficiency of the fluid machine 10. Roller bearings 42 reduce frictional losses by reducing the frictional resistance experienced by the shafts 24 and 26 as they rotate within the holes 32, 34, 36, and 38. Also, it should be noted that the piston rotor 18 is fixed to and rotates with the shaft 24, the gate rotor 22 is fixed to and rotates with the shaft 26, and both shafts 24 and 26 are centrally located within the cylinders defining the respective lobes 16 and 20. Thus the piston rotor IB and the gate rotor 22 can rotate within their respective lobes 16 and 20. The rotation of the piston rotor 18 and that of the gate rotor 22 are synchronized by a pair of intermeshing gears 44 and 46, the gear 44 being fixed to the piston rotor shaft 24 and the gear 46 being fixed to the gate rotor shaft 26. Key 23 fixes the gear 44 to the piston rotor shaft 24, while key 25 fixes the gear 46 to the gate rotor shaft 26. In the embodiment of Figs. 1-10 and 12-15, the gears 44 and 46 have a one to one ratio. Therefore, given the fact that the gears 44 and 46 are fixed to and rotate with the shafts 24 and 26 respectively, the piston rotor 18 and the gate rotor 22 will rotate at the same rotational speed. However, because of the general nature of the rotational motion of intermeshing gears, the piston rotor 18 and the gate rotor 22 will rotate in opposite directions. For example, if the piston rotor 18 rotates in a clockwise direction, then the gate rotor 22 will rotate in a counterclockwise direction. Power can be applied to either of the shafts 24 and 26 when using the fluid machine 10 as a pump or a compressor, and power can be derived from either of the shafts 24 and 26 when using the fluid machine 10 as an internal combustion engine or as an expansion engine.

The piston rotor has a cylindrical portion 48 which is concentric with the piston rotor shaft 24. This cylindrical portion 48 is smaller in diameter than the first lobe 16 which houses the piston rotor 18. A vane 50, extending along the length of the cylindrical portion 48 of the piston rotor 18, projects radially from the outer surface of the cylindrical portion 48 of the piston rotor 18. The vane 50 spans the gap between the cylindrical portion 48 of the piston rotor 18 and the internal surface of the lobe 16. The gate rotor 22 is essentially cylindrical with a trough or cutout 52 along its length. The gate rotor 22 has a diameter that is substantially the same as the diameter of the lobe 20 which houses the gate rotor 22. Also, the diameter of the gate rotor 22 is such that it continuously contacts the outer surface of the cylindrical portion 48 of the piston rotor 18, except when the vane 50 of the piston rotor 18 sweeps through portions of the volume swept by the gate rotor 22. The rotation of the piston rotor 18 and the gate rotor 22 are synchronized such that the cutout 52 in the gate rotor momentarily accommodates the vane 50 as the vane 50 sweeps through portions of the volume swept by the gate rotor 22. Thus the vane 50 of the piston rotor is prevented from catastrophically colliding with the gate rotor 22. It is preferable to minimize the amount of material missing from the gate rotor 22, in forming the trough 52. To obtain the profile which gives the minimum volume for the trough 52, the following procedure can be used. First a circular disk, havincj the same diameter as the gate rotor 22, is cut from a piece of cardboard. This first piece of cardboard simulates the gate rotor 22. Next, a piece of cardboard having the shape of the end profile of the piston rotor 18 is obtained by cutting a larger piece of cardboard to the proper shape. In other words, the second piece of cardboard is cut into the shape of a circular disk having the diameter of the cylindrical portion 48 of the piston rotor 18, and having a projection of roughly uniform thickness projecting radially from its circumference. This second piece of cardboard simulates the piston rotor 18, with the radial projection having the outline of and simulating the vane 50.

The two cardboard pieces are laid on a flat surface such that the circumference of the piece simulating the gate rotor 22 abuts the circumference of the circular portion of the piece simulating the piston rotor 18. Also, the radial projection simulating vane 50 must just abut the circumference of the piece simulating the gate rotor 22 without overlapping any portion of the piece simulating the gate rotor. At this time, a line drawn between the center of the piece simulating the gate rotor 22 and the center of: the circular portion of the piece simulating the piston rotor 18. This line will also pass through the point at which ths circumferences of the piece simulating the gate rotor 22 and ths circular portion of the piece simulating the piston rotor 18 abut one another. The half of this line lying on the piece simulating the gate rotor 22 establishes a baseline on that piece. The other half of the line establishes a baseline on the circular portion of the piece simulating the piston rotor 18.

Once the baselines are established, a series of index lines are drawn on both the piece simulating the gate rotor 22 and the circular portion of the piece simulating the piston rotor 18. The index lines on the piece simulating the gate rotor 22 are drawn radially from the center to the circumference at five degree intervals starting from the baseline. Similarly, the index lines on the circular portion of the piece simulating the piston rotor 18 are drawn radially from the center to the circumference at five degree intervals starting from the baseline.

Once again the two cardboard pieces are laid on a flat surface such that the circumference of the piece simulating the gate rotor 22 abuts the circumference of the circular portion of the piece simulating the piston rotor 18, while the radial projection simulating vane 50 also abuts the circumference of the piece simulating the gate rotor without overlapping any portion of the piece simulating the gate rotor. It should readily be apparent that with the cardboard pieces arranged as described above, the baselines on the two pieces will be in alignment. Next, the two pieces are rotated simultaneously, in opposite directions, in a manner resembling the rotation of the actual piston and gate rotors 18 and 22. For this first rotation, both pieces are rotated through five degrees and this five degree rotation can be easily accomplished by rotating the simulated gate rotor and the simulated piston rotor until the pair of index lines, just ahead of the pair of baselines, are brought into alignment with one another while maintaining the circumference of the simulated gate rotor in abutting contact with the circumference of the circular portion of the simulated piston rotor. The projection simulating vane 50 is allowed to slip over the surface of the simulated gate rotor during the rotation process. Once the rotation is complete the outline of the portion of the projection simulating vane 50 which lies over the surface of the simulated gate rotor, is traced on to the surface of the simulated gate rotor. Then the next pair of index lines are brought into alignment, the simulated rotors being rotated in the same respective directions as before, and the outline of the portion of the simulated vane overlapping the simulated gate rotor is again traced on to the surface of the simulated gate rotor. This process of rotating and tracing is repeated until the simulated vane clears the surface of the simulated gate rotor. Next, a curve tangent to all the outlines of the simulated vane traced on to the surface of the simulated gate rotor, is drawn on the surface of the simulated gate rotor. This curve will have a concave side and a convex side. All the tracings of the simulated vane must be contained on the concave side of the curve with no portion of any of the tracings projecting onto the convex side o:: the curve. The curve thus obtained will define the optimum profile of the trough 52. It should be noted that for best results the simulated gate rotor and the simulated piston rotor must duplicate the profile of the actual gate rotor 22 and the actual piston rotor 18 exactly as they would appear in the assembled engine. This means that if there are any small projections in the profile of the piston and gate rotors, due to sealing strips for example, these small projections should be included in the outline of the simulated piston and gate rotors. The sealing strips are discussed later herein.

The figure eight chamber 14 is formed by two overlapping cylindrical volumes, one volume corresponding to the first lobe 16 housing the piston rotor 18 and the other volume corresponding to the second lobe 20 housing the gate rotor 22. Where the surfaces of the cylindrical volumes intersect, two cusps 54 and 56 are formed on either side of the figure eight chamber 14. Inlet and outlet openings, 58 and 60 respectively, are provided in the wall of the lobe 16. The inlet opening 58 is located proximate the first cusp 54, and the outlet opening 60 is located proximate the second cusp 56. The inlet opening 58 communicates with the exterior of the housing 12 via an inlet duct 59, while the outlet opening 60 communicates with the exterior of the housing 12 via an outlet duct 61. The portion of the machine cycle during which the vane is sweeping over the outlet opening 60, through the region of overlap between the cylindrical volume defining the lobe 16 and the cylindrical volume defining the lobe 20, and over the inlet opening 58, is referred to herein as the transition period. The portion of the machine cycle during which the vane is sweeping over the inner surface of the lobe 16, is referred to herein as the working period.

During the working period, the gate rotor 22 abuts the outer surface of the cylindrical portion 48 of the piston rotor 18, thereby preventing fluid from passing between the cylindrical portion of the piston rotor and the gate rotor except maybe for minor leakage. The sealing action of the gate rotor 22 against the cylindrical portion 48 of the piston rotor 18 during the working period is critical to the proper functioning of the fluid machine 10. In the absence of effective sealing between the gate rotor 22 and the cylindrical portion 48 of the piston rotor 18, when the fluid machine 10 is being used as a pump, fluid ahead of the vane 50 would flow back around the cylindrical portion 48 of the piston rotor 18 instead of flowing out through the outlet opening 60, resulting in a greatly diminished pumping action. In the absence of effective sealing between the gate rotor 22 and the cylindrical portion 48 of the piston rotor 18, when the fluid machine 10 is being used as an expander, fluid would flow directly from the inlet opening 58 to the outlet opening 60 without impinging on the vane 50, resulting in diminished or no momentum transfer to the piston rotor 18. Hence the need for the sealing strips which are discussed hereinafter. During the working period, the vane 50 substantially seals the gap between the cylindrical portion 48 of the piston rotor 18 and the peripheral wall of the lobe 16 housing the piston rotor. The working volume is defined as the portion of the volume of the lobe 16 not displaced by the gate rotor 22 and the cylindrical portion 48 of the piston rotor. Thus, during the working period, the vane 50 divides the working volume within the figure eight chamber 14 into two volumes. The first volume is referred to as the leading control volume, which is the volume extending between the vane 50 and the outlet opening 60 along the direction of rotation of the piston rotor 18 toward the outlet opening 60 (i.e. the volume located ahead of the vane 50 as the vane rotates) . The second volume is referred to as the lagging control volume, which is the volume extending between the inlet opening 58 and the vane 50 along the direction of rotation of the piston rotor 18 as it rotates toward the outlet opening 60 (i.e. the volume located behind the vane 50 as the vane rotates) .

In general, it will always be true that the piston rotor 18 rotates in a direction such that the vane 50 moves away from the inlet opening 58 and toward the outlet opening 60 during the working period. Therefore, during the working period, the leading control volume contracts while the lagging control volume expands as the vane 50 rotates away from the inlet opening 58 and toward the outlet opening 60. Thus fluid is ejected from the leading control volume, through the outlet opening 60, while the lagging control volume is filled by fluid drawn through the inlet opening 58.

Once the vane 50 passes the rim of the outlet opening 60, the lagging control volume, and consequently the inlet opening 58, will be in direct fluid communication with the outlet opening 60. Direct fluid communication between the inlet opening 58 and the outlet opening 60, when the fluid machine 10 is being used as a pump, will result in fluid flowing from the outlet opening 60 back to the inlet opening 58. Such a condition would negate the pumping action of the fluid machine 10. Direct fluid communication between the inlet opening 58 and the outlet opening 60, when the fluid machine 10 is being used as an expansion engine, will result in high pressure fluid flowing directly from the inlet opening 58 to the outlet opening 60 without imparting energy to the piston rotor 18 thus leading to a loss of high pressure fluid without the extraction of any energy from that high pressure fluid. Likewise, such a condition would negate the extraction of energy by the fluid machine 10. To avert such disastrous consequences, a valve 62 must be provided downstream of the outlet opening 60 (see Fig. 12) . Such a valve 62, generally referred to herein as a transfer valve, should be open for substantially the entire working period and closed for substantially the entire transition period. For pumping and compressing applications, a simple check valve may suffice as the transfer valve. The check valve will close when the pressure at the outlet opening 60 drops below the pressure downstream of the valve .

Alternatives to the check valve that are sufficient to function as the transfer valve include poppet type or rotary type valves which are timed to open and close in response to the position of the piston rotor. In the case of the rotary valve a system of timing gears, belts, and/or chains could be used to synchronize the opening and closing of the rotary valve with the position of the piston rotor 18. In the case of the poppet type valves the system of timing gears, belts, and/or chains would synchronize the rotation of a cam shaft, which in turn actuates the poppet valve, with the rotation of the piston rotor 18. However, the rotary valve would seem to be better suited for use as the transfer valve 62, because it is simpler in construction and thus it would be easier to time and coordinate the motion of the rotary valve with the motions of the other rotary parts of the fluid machine 10.

Referring to Fig. 10, a rotary valve 64 suitable for use as the transfer valve 62 is shown. The rotary valve 64 includes a fixed block 66 having a cylindrical chamber 68 bored in its center. A cylindrical valve rotor 70 is housed within the chamber 68. The valve rotor 70 has two shafts 72 and 74 projecting from either end thereof. The shafts 72 and 74 are rotatably supported, via ball bearing sets 76, by end plates or covers 78 and 80, respectively. The covers 78 and 80 also act as closures for the ends of the chamber 68. This arrangement allows the valve rotor 70 to be rotatably supported within the chamber 68.

The block 66 has a channel or duct 82 passing therethrough. The duct 82 extends in a direction transverse to the chamber 68. The duct 82 intersects the wall of the chamber 68 on opposite sides of the chamber 68, forming inlet and outlet openings (not shown) to the chamber 68. The valve rotor 70 has a duct 84 running transversely therethrough, the duct 84 forming a pair of openings (only one shown) in the surface of the valve rotor 70. The valve rotor 70 essentially fills the chamber 68 such that fluid flow through the valve 64 can occur only when one opening of the duct 84 overlaps the inlet opening of the chamber 68 while the other opening of the duct 84 overlaps the outlet opening of the chamber 68. As the valve rotor 70 rotates, the openings in the surface of the valve rotor will overlap the inlet and outlet openings in the wall of the chamber 68 during parts of each rotation, while there will be no overlap during the other parts of each rotation. Thus as the valve rotor 70 goes through each revolution, the valve 64 will be open during part of each revolution while being closed for the remainder of the duration of each revolution. By tailoring the size of the opening in the surface of the valve rotor 70 and/or the size of the inlet and outlet openings in the wall of the chamber 68, the interval of time during which the valve 64 is open can be set at any desired amount . Usually, the interval of time during which the valve 64 is open would be matched to the duration of the working period of the fluid machine 10. However, in certain gas applications it mciy be desirable to have the valve 64 open for only a portion of the working period. It should be apparent from the structure of the valve 64 that the valve will open twice during each revolution of the valve rotor 70. Therefore the rotational speed of the valve rotor 70 should be half that of the piston rotor 18.

Referring to Figs. 7A-7C, an alternative to using a separate transfer valve is seen. In the embodiment of Figs. 7A-7C, the piston rotor 18a has an opening 86 just ahead of the vane 50 (i.e. the opening 86 is close to and on the leading side of the vane 50) . The opening 86 communicates, via a duct or passage 88, with an opening 90 in an end face 92a of the cylindrical portion 48a of the piston rotor 18a. This embodiment lacks the outlet opening 60 near the cusp 56. Instead, an opening 60a is provided in the plate 30a near the hoλe 36. During a portion of the working period the exit hole 90 of the duct 88 will overlap the outlet 60a allowing fluid ahead of the vane 50 to be ejected through the outlet 60a. At times when the exit 90 does not overlap the outlet 60a, no fluid communication can occur between the outlet 60a and the leading control volume ahead of the vane 50. Thus the piston 18a itself acts as the transfer valve. For incompressible fluid applications, the outlet 60a should extend for an arc roughly coextensive with the limits of the angular movement of the vane 50 during the working period. For compressible fluid applications, the outlet 60a may extend over an arc significantly smaller than the limits of the angular movement of the vane 50 during the working period. For the compressible fluid case, the overlap between the exit 90 and the outlet 60a should preferably occur as late as possible during the working period.

Referring again to Figs. 1, 5, 6, 8A-8F, and 12, just as tte vane 50 reaches the rim of the outlet opening 60, the valve 62 of an appropriate type provided downstream of the outlet 60 closes in order to prevent unrestricted fluid communication between the inlet 58 and the outlet opening 60. This vane position also marks the beginning of the transition period. The transition period ends once the vane 50 passes the inlet opening and just reaches the portion of the wall of the first compartment 16 which extends between the inlet 58 and the outlet 60. The valve 62 now opens and the process is repeated resulting in continuous pumping of the fluid from the inlet 58 to the outlet 60. To enable the moving parts of the fluid machine 10 to move freely, inevitably some clearance between the walls of the figure eight chamber 14 and the piston and the gate rotors 18 and 22 will be necessary. However, this clearance can lead to leakage, around the piston and the gate rotors 18 and 22, which will reduce the pumping efficiency of the fluid machine 10. A network of spring loaded sealing strips are provided on the piston rotor 18 and the gate rotor 22 to minimize any leakage and thus increase efficiency as much as possible.

Referring to Figs. 2, 3, 14, and 15, the piston rotor 18 and the gate rotor 22 are each provided with a series of grooves to house and support the sealing strips used in the sealing of the various gaps in the fluid machine 10. The piston rotor 18 has a first circular groove 94 in the first end face 92 and a second circular groove 96 in the second end face 98. The piston rotor 18 further has a first plurality of longitudinal grooves 100 radially distributed on the outer surface of the cylindrical portion 48 of the piston rotor 18. Each longitudinal groove 100 extends between the end face 92 and the end face 98 of the piston rotor 18. The piston rotor 18 also has a first plurality of radial grooves 102 and a second plurality of radial grooves 104 (only one such groove is visible in Fig. 14, but the grooves 104 are mirror images of grooves 102) . Each of the radial grooves 102 extends radially from the first circular groove 94 to a respective one of the first plurality of longitudinal grooves 100. Each of the radial grooves 102 has a wider portion 106 adjacent the first circular groove 94.

Similarly, each of the second plurality of radial grooves 104 extends radially from the second circular groove 96 to a respective one of the first plurality of longitudinal grooves 100. Also, each of the second plurality of radial grooves 104 has a wider portion 108 adjacent the second circular groove 96.

A first vane end groove 110 extends radially from the first circular groove 94 to the top surface 112 of the vane 50. Also, a second vane end groove 114 extends radially from the second circular groove 96 to the top surface 112 of the vane 50. A vane top groove 116 extends from the first vane end groove 110 to the second vane end groove 114 along the top surface 112 of the vane 50. As with the grooves 102 and 104, the first vane end groove 110 and the second vane end groove 114 each have wider portions, 118 and 120 respectively, adjacent a respective one of the circular grooves 94 and 96.

The gate rotor 22 has first circular arc shaped groove 124 in the first end face 126 thereof, and a second circular arc shaped groove is formed in the second end face of the gate rotor. The gate rotor 22 also has a plurality of longitudinal grooves 128 radially distributed on its partial cylindrical outer surface. Each of the longitudinal grooves 128 extends along the entire length of the gate rotor 22. Additionally, the gate rotor 22 has a plurality of radial grooves 130 extending between the groove 124 and respective ones of the grooves 128. Each of the radial grooves 130 has a wider portion 132 adjacent the circular arc shaped groove 124. A similar plurality of radial grooves are also formed in the end face of the gate rotor 22 opposite the end face 126 (i.e. the second end face of the gate rotor) . The radial grooves formed in the second face of the gate rotor 22 also have wider portions adjacent the second circular arc shaped groove similar to the wider groove portions 132. The second end face of the gate rotor 22, the radial grooves formed therein, the wider groove portions formed therein, and the circular arc shaped groove formed therein are mirror images of the end face 126, the grooves 130, the wider groove portions* 132, and the circular arc shaped groove 124 respectively, and are therefore not shown separately in the drawings.

Internally the grooves formed in the gate rotor 22 are identical to the corresponding grooves formed in the piston rotor 18. Therefore sectioned views of the gate rotor 22, showing the internal structure of its grooves, have not been included in the drawings. In other words, the grooves in the gate rotor 22 also have cavities housing springs, provided at the bottoms of the grooves, similar to those shown in Figs. 14 and 15 for the piston rotor 18. The springs (not shown) in the gate rotor 22 also function to bias sealing strips outward from the grooves in the gate rotor, in the same manner as will be discussed in relation to the piston rotor below. The circular arc shaped groove 124, and its mirror image in the second face of the gate rotor, differ from the grooves 94 and 96 in the piston rotor only in that the groove 124 and its mirror image do not form a complete circle due to the presence of the cutout 52.

At the bottom of the grooves in the piston and gate rotors, several cavities are drilled which house springs. The various cavities and springs are shown in Figs. 14 and 15. These springs serve to bias the sealing strips (described later)- out of their respective grooves so that the sealing strips are maintained in continuous contact with the surfaces against which sealing is required. At the bottom of the groove 94, a plurality of cavities are drilled which house springs 122. A plurality of cavities drilled at the bottom of the groove 96 house springs 134. A plurality of cavities drilled at the bottom of the longitudinal grooves 100 house springs 136. A cavity is provided at the bottom of each radial groove 102, and the cavity houses a spring 138. Similarly, a cavity is provided at the bottom of each radial groove 104, and the cavity houses a spring 140. A plurality of cavities provided at the bottoms of the vane end groove 110, the vane top groove 116, and the vane end groove 114 house springs 142, 144, and 146 respectively. Referring now to Figs. 4A, 4B, 5, and 6, the sealing strips for the piston rotor 18 can be seen. The sealing strips for the piston rotor 18 include two circular sealing strips 148, a plurality of longitudinal sealing strips 150 which are equal in number to the longitudinal grooves 100, and a longitudinal vane sealing strip 152.

One circular sealing strip 148 is slidably held in each of the grooves 94 and 96. Each circular sealing strip 148 has a plurality of pairs of radial projections 154. Each pair of radial projections 154 fits into a respective one of the wider groove portions 106 or 108 of the radial grooves 102 or 104. Springs 122 and 134 bias the ring seals 148 to project out of the grooves 94 and 96 so that the circular sealing strips 148 are in continuous contact with the end plates 30 and 28 even as the sealing strip 148 wears over time. Thus the sealing strips 148 seal the gaps between the end face 92 and the inside surface of the plate 30, and between the end face 98 and the inside surface of the plate 28. The plurality of longitudinal sealing strips 150 each include a first radial portion 156 having a first end and a second end, a first longitudinal portion 158 having a first end and a second end, a second longitudinal portion 160 having a first end and a second end, and a second radial portion 162 having a first end and a second end. The second end of the first radial portion 156 of each of the plurality of longitudinal sealing strips 150 is attached to or otherwise integral with the first end of the first longitudinal portion 158 of each of the first plurality of longitudinal sealing strips 150 such that the first radial portion 156 is approximately at a right angle to the first longitudinal- portion 158. Similarly, the second end of the second radial- portion 162 is attached to or otherwise integral with the first end of the second longitudinal portion 160 such that the second radial portion 162 is approximately at a right angle to the second longitudinal portion 160 of each longitudinal sealing strip 150. Each longitudinal sealing strip 150 also has a sliding contact portion 164 provided at the second end of the first longitudinal, portion 158. A complimentary sliding contact portion 166 is provided at the second end of the second longitudinal portion 163 of each of the longitudinal sealing strips 150. The sliding contact portion 164 overlaps and slidingly contacts the complimentary sliding contact portion 166 to allow each of the longitudinal sealing strips 150 to expand and contract in ths direction of the longitudinal axis of the cylindrical portion 48 of the piston rotor 18.

The sliding contact portion 164 and the complimentary sliding contact portion 166 can have a myriad of different forms as long as they allow for the longitudinal expansion of the sealing strips 150, while not adding to the thickness of the sealing strip 150 an amount sufficient to interfere with the sealing strip's sliding movement within the longitudinal grooves 100. In its simplest form the sliding contact portion 164 can be a portion of sealing strip thinned on one side to half the normal thickness, while the complimentary sliding contact portion 166 is a portion of sealing strip thinned on the side opposite the thinned side of the sliding contact portion 164, also to half the normal thickness. In the illustrated example (see Fig. 4B) , the sliding contact portion 164 is formed by thinning the sealing strip material to half its normal thickness, first on one side for half the width of the sealing strip (the width refers to the dimension of the sealing strip portions 158 and 160 in the radial direction relative to the longitudinal axis of the cylindrical portion 48 of the piston rotor 18) and then on the opposite side for the remaining half of the width of the sealing strip material. The complimentary sliding contact portion 166 is formed similarly, except that the spacial order in which the sides are thinned is reversed compared to the sliding contact portion 164. Thus when the sliding contact portion 164 and the complimentary sliding contact portion 166 overlap and slidably contact one another, the remaining portions 163 and 165 of the sealing strip material of the sliding contact portion 164 mesh with voids left due to the thinning of the sealing strip material of the complimentary sliding contact portion 166 on either side of the sealing strip 150. The illustrated arrangement has the added benefit that the sliding contact portion 164 and the complimentary sliding contact portion 166 will not be laterally pulled apart when the sealing strip 150 scrapes another surface. Each of the longitudinal sealing strips 150 is supported in a respective one of the radial grooves 102, a respective one of the longitudinal grooves 100, and a respective one of the radial grooves 104 with the radial portion 156 lying in the respective radial groove 102, the longitudinal portions 158 and 160 lying in the respective longitudinal groove 100, and the radial portion 162 lying in the respective radial groove 104. The sealing strip 150 is dimensioned to be slidably movable within its supporting grooves, and the sliding contact portion 164 and the complimentary sliding contact portion 166 allow the sealing strip to expand and contract longitudinally. Thus the sealing strip 150 can project in variable amounts from the cylindrical surface of the cylindrical portion 48 of the piston rotor 18 and from the end faces 92 and 98. The springs 138 and 140 tend to push the radial portions 155 and 162 outward from the end faces 92 and 98 so as to maintain the radial portions 156 and 162 in continuous contact with the end plates 30 and 28 even as the radial portions of the sealing strip 150 wear over time. Thus the radial portions 156 and 162 of the sealing strips 150 seal any gaps between the end face 92 and the inside surface of the plate 30 and between the end face 98 and the inside surface of the plate 28, not sealed by circular sealing strips 148. As the radial portions 156 and 162 of the sealing strips 150 wear away, the portion of the sealing strips 150 supported in the grooves 100 must expand in order for the radial portions 156 and 162 to remain in continuous contact with the end plates 30 and 28. The sliding contact portion 164 and the complimentary sliding contact portion 166 allow the portion of the sealing strips 150 supported in the grooves 100 to expand without leaving any gaps that would detrimentally affect the sealing function of the sealing strips 150. The springs 136 tend to push the portions of the sealing strips 150 supported in the grooves 100 outward from the outer surface of the cylindrical portion 48 of the piston rotor 18. As the piston rotor 18 rotates, the sealing strip portions 158 and 160 orbit about the shaft 24 and pass through the location at which the circumferences of the cylindrical portion 48 of the piston rotor 18 and the gate rotor 22 are closest together. As the sealing strip portions 158 and 160 pass through this location, they help seal any gaps between the cylindrical portion 48 of the piston rotor 18 and the gate rotor 22.

The radial portions 156 and 162 are provided with notches 168 and 170, respectively. The springs 138 and 140 which push the radial portions 156 and 162 outward, actually press against the recessed bottom of the notches 168 and 170. The length of the notches (i.e. the dimension of the notches measured along the length of the radial portions 156 and 162) is larger than the outside diameter of the coil springs 138 and 140. Thus the sealing strips 150 can have radial movement even as the springs 138 and 140 project into the notches 168 and 170. The notches are provided so that the sealing strips 150 will not fall out of their supporting grooves when the sealing strips 150 are not in the region of the location at which the circumferences of the cylindrical portion 48 of the piston rotor 18 and the gate rotor 22 are closest together.

When assembled, the ends of the sealing strip portions 156 and 162 distal from portions 158 and 160, will fit between the respective pairs of radial projections 154 located in the wider groove portions 106 and 108. This arrangement allows the sealing strips 150 to move radially away from the circular sealing strips 148 without leaving any open gaps between the radial portions of the sealing strips 150 and the circular sealing strips 148.

The longitudinal vane sealing strip 152 includes a first radial portion 172 having a first end and a second end, a first longitudinal portion 174 having a first end and a second end, a second longitudinal portion 176 having a first end and a second end, and a second radial portion 178 having a first end and a second end. The second end of the first radial portion 172 of the vane sealing strip 152 is attached to or otherwise integral with the first end of the first longitudinal portion 174 such that the first radial portion 172 is approximately at a right angle to the first longitudinal portion 174. Similarly, the second end of the second radial portion 178 is attached to or otherwise integral with the first end of the second longitudinal portion 176 such that the second radial portion 178 is approximately at a right angle to the second longitudinal portion 176. The longitudinal vane sealing strip 152 also has a sliding contact portion 180 provided at the second end of the first longitudinal portion 17 . A complimentary sliding contact portion 182 is provided at the second end of the second longitudinal portion 176 of the longitudinal vane sealing strip 152. The sliding contact portion 180 and the complimentary sliding contact portion 182 are structurally identical and function in exactly the same manner as the sliding contact portions 164 and 166 previously described.

The longitudinal vane sealing strip 152 is supported in the first vane end groove 110, the vane top groove 116, and the second vane end groove 114 with the radial portion 172 lying in the groove 110, the longitudinal portions 174 and 176 lying in the groove 116, and the radial portion 178 lying in the groove 114. The sealing strip 152 is dimensioned to be slidably movable within its supporting grooves, and the sliding contact portion 180 and the complimentary sliding contact portion 182 allow the sealing strip to expand and contract longitudinally. Thus the sealing strip 152 can project in variable amounts from the top surface 112 of the vane 50, from the end faces 92 and 98, and from vane end faces 184 and 186.

The springs 142 and 146 tend to push the radial portions 172 and 178 outward from the grooves 110 and 114 so as to maintain the radial portions 172 and 178 in continuous contact with the end plates 30 and 28 even as the radial portions of the sealing strip 152 wear over time. Thus the radial portions 172 and 178 of the vane sealing strip 152 seal any gaps between the end face 92 and the inside surface of the plate 30 not sealed by the circular sealing strip 148, between the end face 98 and the inside surface of the plate 28 not sealed by the circular sealing strip 148, between the vane end face 184 and the inside surface of the plate 30, and between the vane end face 186 and the inside surface of the plate 28. As the radial portions 172 and 178 of the sealing strip 152 wear away, the portion of the sealing strip 152 supported in the groove 116 must expand in order for the radial portions 172 and 178 to remain in continuous contact with the end plates 30 and 28. The sliding contact portion 180 and the complimentary sliding contact portion 182 allow the portion of the sealing strip 152 supported in the groove 116 to expand without leaving any gaps that would detrimentally affect the sealing function of the sealing strip 152. The springs 144 tend to push the portions of the sealing strip 152 supported in the groove 116 outward from the top surface 112 of the vane 50. As the piston rotor 18 rotates, the sealing strip portions 174 and 176 remain in continuous contact with the internal peripheral surface of the compartment 16, thus sealing any gaps between the top vane surface 112 and the peripheral wall of the compartment 16.

The radial portions 172 and 178 are provided with notches 188 and 190. The springs 142 and 146, proximate wider groove portions 118 and 120, push the radial portions 172 and 178 outward by pressing against the recessed bottom of the notches 188 and 190. The length of the notches (i.e. the dimension of the notches measured along the length of the radial portions 172 and 178) is larger than the outside diameter of the coil springs 142 and 146. Thus the sealing strip 152 can have radial movement even as the springs 142 and 146, proximate the wider groove portions 118 and 120, project into the notches 188 and 190. The notches are provided so that the sealing strip 152 will not fall out of its supporting grooves when the sealing strip 152 loses contact with the peripheral wall of the compartment 16.

When assembled, the ends of the sealing strip portions 172 and 178 distal from portions 174 and 176, will fit between the respective pairs of radial projections 154 located in the wider groove portions 118 and 120. This arrangement allows the sealing strip 152 to move radially away from the circular sealing strips 148 without leaving any open gaps between the radial portions of the sealing strip 152 and the circular sealing strips 148. Referring now to Figs. 3, 5, and 6, the sealing strips and associated grooves for the gate rotor 22 can be seen. The sealing strips for the gate rotor 22 include two circular arc shaped sealing strips 192 (only one shown) and a plurality of longitudinal sealing strips 194 which are equal in number to the longitudinal grooves 128.

One of the circular arc shaped sealing strips 192 is slidably held in the groove 12 . The circular arc shaped sealing strip 192 has a plurality of pairs of radial projections 196. Each pair of radial projections 196 fits into a respective one of the wider groove portions 132. The radial projections 196 function identically to the radial projections 154. Similar to the circular sealing strips 148, the circular arc shaped sealing strip 192 is biased to project out of the groove 124. The circular arc shaped sealing strip 192 seals the gap between the end face 126 and the inside surface of the plate 30. The other circular arc shaped sealing strip 192 (not shown) is identical to the one illustrated and fits in a groove similar to the groove 124 in the end face of the gate rotor 22 which is opposite the end face 126. The circular arc shaped sealing strip 192 which is not illustrated in the drawings, seals the gap between the end face of the gate rotor 22 which is opposite the end face 126 and the inside surface of the plate 28. As mentioned previously, the end face of the gate rotor 22 which is opposite the end face 126 is a mirror image of the end face 126 and is therefore not illustrated in the drawings .

The plurality of longitudinal sealing strips 194 are identical in every way to the sealing strips 150. The plurality of longitudinal sealing strips 194 are mounted and biased in their supporting grooves in exactly the same manner as the sealing strips 150 are mounted in theirs. The plurality of longitudinal sealing strips 194 seal the gap between the partial cylindrical outer surface of the gate rotor 22 and the peripheral wall of the compartment 20. Also, the plurality of longitudinal sealing strips 194, in cooperation with the sealing strips 150, seal any gap between the cylindrical portion 48 of the piston rotor 18 and the partial cylindrical outer surface of the gate rotor 22 during the working period. In addition, the plurality of longitudinal sealing strips 194, in cooperation with the sealing strips 192, seal the gaps between the end face 126 and the inside surface of the plate 30, and between the end face of the gate rotor 22 which is opposite the end face 126 and the inside surface of the plate 28. Preferably, each of the sealing strips 194 registers with a respective one of the sealing strips 150 as each of the sealing strips 194 and the respective one of the sealing strips 150 reach the location at which the circumferences of the cylindrical portion 48 of the piston rotor 18 and the gate rotor 22 are closest together. This arrangement provides for better sealing. To obtain an even better seal, the projecting edge of the longitudinal portions of one set of sealing strips 194 or 150 could have a concave profile, while the projecting edge of the longitudinal portions of the other set of sealing strips would have a complementary convex profile such that the two sealing strips 194 and 150 would mesh when they are in registry with one another. The sealing strips 194 and 150 can be made of the same material as the piston rings in conventional reciprocating piston internal combustion engines . Although coil springs have been used in the illustrated example, it should be kept in mind that leaf springs and other suitable biasing means can also be used without departing from the spirit and scope of the present invention. The rotary piston fluid machine 10 can be lubricated in a manner similar to conventional engines in gas applications. In many liquid applications, the fluid being pumped can itself act as a lubricant. Referring to Fig. 13, the block 12 can be provided with a cavity or sump 198 which acts as a lubricant reservoir. The sump is contiguous with the second compartment 20 such that the gate rotor 22 will be partially immersed in the lubricant contained in the sump 198. As the gate rotor 22 rotates partially immersed in the lubricant in the sump, its surfaces and the surfaces of the compartment 20 will automatically be lubricated.

An oil pump (not shown) running off of the shafts 24 or 26 would also pump lubricant from the sump 198 through lubricant passages

(not shown) in the block 12. These lubricant passages would then communicate with small orifices (also not shown) in the walls of the compartment 16 allowing the lubrication of the walls of the compartment 16 and the piston rotor 18. The block 12 is also provided with coolant passages 199 which are distributed around the figure eight chamber 14. Most of the coolant passages 199 run along the length of the block 12 parallel to the wall of the figure eight chamber, except for the coolant passages located around the bottom of the compartment 20. Obviously, the coolant passages located around the bottom of the compartment 20 must be routed around the sump 198 to keep the coolant and the lubricant from mixing. The arrangement of coolant passages illustrated in Fig. 13 is intended merely as an example, and it should readily be apparent to those skilled in the art that a myriad of other geometries can be used for the coolant passages.

Referring now to Fig. 9, an alternative lubrication system is shown. In this system the shaft 24, which may be of one piece construction (i.e. integral) with the piston rotor 18, has a longitudinal lubricant passage 200 therein. This longitudinal lubricant passage 200 communicates with a pair of radial lubricant passages 202 in the piston rotor 18. The pair of radial lubricant passages 202 communicate with a plurality of lateral branching lubricant passages 204. The pair of radial lubricant passages 202 terminate in respective orifices in the top surface 112 of the vane 50. The lateral branching lubricant passages 204 terminate in respective orifices in the end surfaces 184 and 186 of the vane 50. The longitudinal lubricant passage 200 communicates with the sump 198. As the piston rotor 18 rotates, it acts as a centrifugal pump drawing lubricant from the sump 198 and forcing the lubricant out through the orifices in the surfaces of the vane 50. Thus the walls of the compartment 16 and the surfaces of the piston rotor 18 are lubricated. The lubricant forced through the orifices in the surfaces of the vane 50, drips back into the sump due to gravity and can be continuously recirculated. If the centrifugal force provided by the piston rotor 18 does not provide sufficient lubricant flow, then an oil pump can be added to assist with the pumping of the lubricant to the lubricant passages in the piston rotor 18. As before this pump would run off of the shafts 24 or 26.

Referring specifically to Fig. 12, two rotary piston fluid machines 206 and 208 are used to form an internal combustion engine. The machines 206 and 208 are identical to the fluid machine 10. The machine 206 will be used as a compressor and the machine 208 will be used as an expansion engine. The internal combustion engine illustrated in Fig. 12 can be operated according to either the Otto cycle or the diesel cycle. When operated in accordance with the Otto cycle, the engine cycle begins when fuel/air mixture is drawn into the lagging control volume of the machine 206 from the carburetor 210. During the following working period this combustible mixture is compressed in the leading control volume of the machine 206. Note that as the fuel/air mixture is being compressed in the leading control volume of the machine 206, the lagging control volume of the machine 206 is being filled with fresh fuel/air mixture for use in the subsequent engine cycle. Just before this working period ends the transfer valve 62 opens and the compressed mixture is forced into the lagging control volume of the machine 208. The piston rotor of the machine 208 is at the beginning of its working period when the transfer valve 62 opens. Shortly after the valve 62 opens the piston rotor of the machine 206 reaches the end of its working period, at which time the transfer valve 62 closes. This completes the transfer of the combustible mixture. The piston rotor of the machine 208 is now at a position that is relatively early in its working period, and it has a compressed combustible mixture in its lagging control volume. Immediately after the transfer valve 62 closes, a spark is used to ignite the compressed combustible mixture in the lagging control volume. The spark can be provided by a conventional spark plug located in a recess (not shown) in the wall of the piston rotor compartment of the machine 208. The combustion gases in the lagging control volume of the machine 208 expand, pushing and forcing the piston rotor of the machine 208 to turn. Once the piston rotor of the machine 208 reaches the end of its working period, the outlet opening of the machine 208 is uncovered thereby allowing the combustion gases to be partially exhausted. The remainder of the combustion gases will occupy the leading control volume during the subsequent revolution of the piston rotor of the machine 208, and will be pushed out during this subsequent revolution. When operated according to the diesel cycle, the carburetor 210 will not be required. Instead a fuel injector (not shown) will be required to inject fuel into the lagging control volume of the machine 208 at the proper time. The diesel engine cycle begins when air is drawn into the lagging control volume of the machine 206. During the following working period of the machine 206, this air will occupy the leading control volume of the machine 206 and will be compressed. Note that as the air in the leading control volume of the machine 206 is being compressed, the lagging control volume of the machine 206 is filling with air for use in the subsequent engine cycle. A short time before the piston rotor of the machine 206 reaches the end of its working period, the transfer valve 62 opens and the compressed air form the leading control volume of the machine 206 is transferred into the lagging control volume of the machine 208. When the air transfer begins, the piston rotor of the machine 208 must be at the beginning of its working period.

Fuel is injected into the lagging control volume of the machine 208 during the transfer of the compressed air. In a diesel cycle engine fuel is preferably injected while the air is still being compressed. To ensure that air is still being compressed as it is being transferred, the working volume (i.e. the arc shaped volume between the peripheral wall of the compartment 16 and the cylindrical portion of the piston rotor, and extending from the inlet opening to the outlet opening) of the machine 206 should be larger than the working volume of the machine 208.

The fuel injected into the lagging control volume of the machine 208 will ignite as it is being injected. The ignition will either be spontaneous because the compressed air becomes hot due to adiabatic compression, or the fuel can be ignited with the aid of a glow plug. After ignition, the expanding combustion gases force the piston rotor of the machine 208 to turn, yielding useful torque at the output shaft of the machine 208.

A check valve (not shown) is installed between the transfer valve 62 and the inlet opening of the machine 208. This check valve will prevent the expanding, high pressure gases from flowing back into the machine 206. The transfer valve 62 can be closed after the check valve has closed. Once the working period of the machine 208 ends the combustion gases are partially exhausted, the remaining combustion gases being exhausted during the subsequent working period. The cycle can now begin again allowing the engine to operate continuously. The movements of the rotors of the machines 206 and 208, and the transfer valve 62, are of course coordinated by well known timing mechanisms (not shown) including gears, belts, chains, or combinations thereof.

The machines 206 and 208 can be arranged either in tandem cr in parallel. When arranged in tandem, the shaft of the piston rotor of machine 206 will be in line with and coupled to the shaft of the piston rotor of machine 208, and the shaft of the gate rotor of machine 206 will be in line with and coupled to the shaft of the gate rotor of machine 208. When arranged in parallel, the shaft of the piston rotor of machine 206 will be parallel to but not in line with the shaft of the piston rotor of machine 208, and the shaft of the gate rotor of machine 206 will be parallel to but not in line with the shaft of the gate rotor of machine 208. In the parallel arrangement, the shafts of one machine must be coupled to the shafts of the other machine, for example, by gears. Referring to Figs. 11A-11D, it can be seen that many different arrangements or combinations of rotary fluid machines can be derived from the basic fluid machine 10. Referring to Fig. 11A, an internal combustion machine of the same type as that of Fig. 12 is shown which has the compressor 206 and the expansion engine 208 integrally made in the same block 212. As shown in Fig. 11B, multiple sets of compressors 206 and expansion engines 208 can be integrally made in the same block 214 to match the performance of multi-cylinder reciprocating piston engines.

Other compact rotary piston machine configurations are shown in Figs. 11C and 11D. The configuration of Fig. 11C allows the equivalent of four rotary piston machines to be packed into a compact block 216 by sharing a single gate rotor 22 with four piston rotors 18. Similarly, the configuration of Fig. 11D allows the equivalent of four rotary piston machines to be packed into a compact block 218 by surrounding a single piston rotor 220, which has four vanes similar to the vane 50, with four gate rotors 22.

It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.

Claims

CLAIMSI claim:

1. A rotary piston fluid machine for transferring shaft work between a fluid and a rotating shaft, the rotary piston fluid machine comprising: a block having an internal surface, a first end surface and a second end surface which collectively define a chamber, said chamber being formed of a first substantially cylindrical compartment and a second substantially cylindrical compartment in overlapping relation with said first compartment, said first compartment and said second compartment intersecting along a first cusp and along a second cusp, said block also having an inlet in communication with said first compartment and an outlet in communication with said first compartment; a piston rotor having a substantially cylindrical portion with a longitudinal axis, an outer surface, a first end face, and a second end face, said piston rotor further having a substantially rectangular vane extending radially from said outer surface thereof, said vane including a top surface, a first end surface, and a second end surface, said piston rotor being rotatably supported within said chamber such that said cylindrical portion of said piston rotor is concentric with said first compartment and said top surface of said vane contacts said internal surface defining said first compartment as said vane sweeps through said first compartment; a gate rotor being substantially cylindrical and having a longitudinal axis, a first end face and a second end face, an outer surface, and a cutout formed in said outer surface and extending the length of said gate rotor, said cutout being dimensioned and configured to receive said vane, said gate rotor being rotatably supported within said chamber such that said gate rotor is concentric with said second compartment and said outer surface of said gate rotor contacting said outer surface of said piston rotor cylindrical portion as said vane sweeps through said first compartment; and synchronizing means for synchronizing rotation of said gate rotor and said piston rotor, said synchronizing means synchronizing registry of said cutout with said vane as said vane sweeps through said second compartment; whereby fluid is ejected from said outlet as said vane sweeps over a portion of said internal surface defining said first compartment between said inlet and said outlet.

2. The rotary piston fluid machine according to claim 1, further comprising: first sealing means on said piston rotor for providing a seal between said piston rotor and said internal surface defining said first compartment, and between said piston rotor and said first end face and said second end face.

3. The rotary piston fluid machine according to claim 2, wherein: said piston rotor having a first circular groove in said first end face thereof and a second circular groove in said second end face thereof; said piston rotor further having a first plurality of longitudinal grooves radially spaced in said outer surface of said piston rotor cylindrical portion, each of said first plurality of longitudinal grooves extending between said first end face of said piston rotor and said second end face of said piston rotor; said piston rotor additionally having a first plurality of radial grooves formed in said first end face and a second plurality of radial grooves formed in said second end face, each of said first plurality of radial grooves extending radially from said first circular groove to a respective one of said first plurality of longitudinal grooves, each of said second plurality of radial grooves extending radially from said second circular groove to a respective one of said first plurality of longitudinal grooves ; and said piston rotor having a first vane end groove extending radially from said first circular groove to said top surface of said vane, a second vane end groove extending radially from said second circular groove to said top surface of said vane, and a vane top groove extending from said first vane end groove to said second vane end groove, said first vane end groove having a wide portion adjacent said first circular groove, said second vane end groove having a wide portion adjacent said second circular groove; said first sealing means comprise: a first circular sealing strip slidably held at least in part in said first circular groove, said first circular sealing strip having a first plurality of radial projections positioned within said first plurality of radial grooves; first biasing means for biasing said first circular sealing strip to project outwardly from said first end face of said piston rotor; a second circular sealing strip slidably held at least in part in said second circular groove, said second circular sealing strip having a second plurality of radial projections positioned within said second plurality of radial grooves; second biasing means for biasing said second circular sealing strip to project outwardly from said second end face of said piston rotor; a first plurality of longitudinal sealing strips each including a first radial portion having a first end and a second end, a first longitudinal portion having a first end and a second end, a second longitudinal portion having a first end and a second end, and a second radial portion having a first end and a second end, each of said first plurality of longitudinal sealing strips having said second end of said first radial portion perpendicularly depending from said first end of said first longitudinal portion and said second end cf said second radial portion perpendicularly depending from said first end of said second longitudinal portion, each of said first plurality of longitudinal sealing strips being supported in a respective one of said first plurality of radial grooves, a respective one of said first plurality of longitudinal grooves, and a respective one of said second plurality of radial grooves so as to project in variable amounts from said respective one of said first plurality of radial grooves, said respective one of said first plurality of longitudinal grooves, and said respective one of said second plurality of radial grooves, and each of said first plurality of longitudinal sealing strips having said first end of said first radial portion partially overlapping one of said first plurality of radial projections, said first end of said second radial portion partially overlapping one of said second plurality of radial projections, and said second end of said first longitudinal portion partially overlapping said second end of said second longitudinal portion; third biasing means for biasing each of said first plurality of longitudinal sealing strips to project outwardly from said first end face, said second end face, and said outer surface of said piston rotor cylindrical portion; a longitudinal vane sealing strip including a first radial portion having a first end and a second end, a first longitudinal portion having a first end and a second end, a second longitudinal portion having a first end and a second end, and a second radial portion having a first end and a second end, said vane sealing strip having said second end of said first radial portion perpendicularly depending from said first end of said first longitudinal portion and said second end of said second radial portion perpendicularly depending from said first end of said second longitudinal portion, said longitudinal vane sealing strip being supported in said first vane end groove, said vane top groove, and said second vane end groove so as to project in variable amounts from said first vane end groove, said vane top groove, and said second vane end groove, and said longitudinal vane sealing strip having said first end of said first radial portion partially overlapping said first plurality of radial projections, said first end of said second radial portion partially overlapping said second plurality of radial projections, and said second end of said first longitudinal portion partially overlapping said second end of said second longitudinal portion; and fourth biasing means for biasing said longitudinal vane sealing strip to project outwardly from said top surface of said vane, said first end surface of said vane, said second end surface of said vane, said first end face of said piston rotor, and said second end face of said piston rotor.

4. The rotary piston fluid machine according to claim 3, wherein : said first plurality of radial projections includes firs- spaced pairs of the radial projections, each of said first pairs being positioned within one of said first plurality of radial, grooves; said second plurality of radial projections includes second spaced pairs of the radial projections, each of said second pairs being positioned within one of said second plurality of radial grooves; and each of said first and second pairs of the radial projections respectively receiving therebetween said first end of said first radial portion and said first end of said second radial portion of one of the piston rotor longitudinal sealing strips.

5. The rotary piston fluid machine according to claim 3, wherein each of said first plurality of longitudinal sealing strips having a sliding contact portion provided at said second end of said first longitudinal portion thereof and a complimentary sliding contact portion provided at said second end of said second longitudinal portion thereof, said sliding contact portion slidably overlapping said complimentary sliding contact portion to thereby allow each of said first plurality of longitudinal sealing strips to expand and contract longitudinally.

6. The rotary piston fluid machine according to claim 3, wherein said longitudinal vane sealing strip having a sliding contact portion provided at said second end of said first longitudinal portion thereof and a complimentary sliding contact portion provided at said second end of said second longitudinal portion thereof, said sliding contact portion slidably overlapping said complimentary sliding to thereby allow said longitudinal vane sealing strip to expand and contract longitudinally.

7. The rotary piston fluid machine according to claim 1, further comprising: second sealing means on said gate rotor for providing a seal between said gate rotor and said internal surface defining said second compartment, said first end face and said second end face.

8. The rotary piston fluid machine according to claim 7, wherein : said gate rotor has a first circular arc shaped groove in said first end face thereof and a second circular arc shaped groove in said second end face thereof; said gate rotor further having a second plurality of longitudinal grooves radially spaced in said outer surface thereof, each of said second plurality of longitudinal grooves extends between said first end face of said gate rotor and said second end face of said gate rotor; and said gate rotor additionally having a third plurality of radial grooves formed in said first face thereof and a fourth plurality of radial grooves formed in said second face thereof, each of said third plurality of radial grooves extending radially from said first circular arc shaped groove to a respective one of said second plurality of longitudinal grooves and each of said fourth plurality of radial grooves extending radially from said second circular arc shaped groove to a respective one of said second plurality of longitudinal grooves,* said second sealing means comprise: a first circular arc shaped sealing strip slidably held at least in part in said first circular arc shaped groove, said first circular arc shaped sealing strip having a third plurality of radial projections; fifth biasing means for biasing said first circular arc shaped sealing strip to project outwardly from said first end face of said gate rotor,* a second circular arc shaped sealing strip slidably held at least in part in said second circular arc shaped groove, said second circular arc shaped sealing strip having a fourth plurality of radial projections; sixth biasing means for biasing said second circular arc shaped sealing strip to project outwardly from said second end face of said gate rotor; a second plurality of longitudinal sealing strips each including a first radial portion having a first end and a second end, a first longitudinal portion having a first end and a second end, a second longitudinal portion having a first end and a second end, and a second radial portion having a first end and a second end, each of said second plurality of longitudinal sealing strips having said second end of said first radial portion perpendicularly depending from said first end of said first longitudinal portion and said second end of said second radial portion perpendicularly depending from said first end of said second longitudinal portion, each of said second plurality of longitudinal sealing strips being supported in a respective one of said third plurality of radial grooves, a respective one of said second plurality of longitudinal grooves, and a respective one of said fourth plurality of radial grooves so as to project in variable amounts from said respective one of said third plurality of radial grooves, said respective one of said second plurality of longitudinal grooves, and said respective one of said fourth plurality of radial grooves, and each of said second plurality of longitudinal sealing strips having said first end of said first radial portion partially overlapping one of said third plurality of radial projections, said first end of said second radial portion partially overlapping one of said fourth plurality of radial projections, and said second end of said first longitudinal portion partially overlapping said second end of said second longitudinal portion; and seventh biasing means for biasing said second plurality of longitudinal sealing strips to project outwardly from said first end face, said second end face, and said outer surface of said gate rotor.

9. The rotary piston fluid machine according to claim 8, wherein: said third plurality of radial projections includes third spaced pairs of the radial projections, each of said third pairs being positioned within one of said third plurality of radial grooves; said fourth plurality of radial projections includes fourth spaced pairs of the radial projections, each of said fourth pairs being positioned within one of said fourth plurality of radial grooves; and each of said third and fourth pairs of the radial projections respectively receiving therebetween said first end of said first radial portion and said first end of said second radial portion of one of the gate rotor longitudinal sealing strips.

10. The rotary piston fluid machine according to claim 8, wherein each of said second plurality of longitudinal sealing strips having a sliding contact portion provided at said second end of said first longitudinal portion thereof and a complimentary sliding contact portion provided at said second end of said second longitudinal portion thereof, said sliding contact portion slidably overlapping said complimentary sliding contact portion to thereby allow each of said second plurality of longitudinal sealing strips to expand and contract longitudinally.

11. The rotary piston fluid machine according to claim 1, wherein said block includes a cavity therein for storing a lubricant, said cavity being contiguous with said second compartment whereby said gate rotor will be partially immersed in the lubricant contained in said cavity; said piston rotor having a longitudinal passage extending along said longitudinal axis of said cylindrical portion of said piston rotor for a predetermined distance, said longitudinal passage communicating with said cavity; said piston rotor also having a first and second radial passages extending from said longitudinal passage to said top surface of said vane; said piston rotor also having a first branch passage extending from said first radial passage to said first end surface of said vane ; and said piston rotor further having a second branch passage extending from said second radial passage to said second end surface of said vane; whereby rotational motion of said piston rotor facilitates movement of the lubricant through said longitudinal passage, said first and second radial passages, and said first and second branch passages to cause the lubrication of said internal surface defining said first compartment.

12. The rotary piston fluid machine according to claim 1, further comprising a valve coupled to said rotary fluid machine downstream of said outlet, said valve being in fluid communication with said first chamber for closure of said valve as said vane rotates into a position allowing direct fluid communication between said inlet and said outlet.

13. The rotary piston fluid machine according to claim 1, wherein said inlet is in communication with said first corapartmen: proximate said first cusp; said outlet extends through said first end surface and is ii communication with said first compartment; said piston rotor further includes an outlet passage extending between an entrance provided in said outer surface of said cylindrical portion thereof and an exit provided in said first end face of said cylindrical portion thereof, said exit registering with said outlet of said block during rotation of said piston rotor; whereby fluid is ejected from said outlet as said vane sweeps over a portion of said internal surface defining said first compartment between said inlet and said second cusp.

14. The rotary piston fluid machine according to claim 1, wherein said inlet is in communication with said first compartment proximate said first cusp and said outlet is in communication with said first compartment proximate said second cusp.