WO1988001696A1

WO1988001696A1 - Trochoidal gas processing devices

Info

Publication number: WO1988001696A1
Application number: PCT/US1986/001837
Authority: WO
Inventors: James T. Duffy
Original assignee: Duffy James T
Priority date: 1986-09-05
Filing date: 1986-09-05
Publication date: 1988-03-10

Abstract

A trochoid-type rotary piston gas processing device comprising a stationary housing (1) having a continuous epitrochoidal sidewall including two semicircular lobes (11, 12) which intersect at a pair of opposed transition edges (13, 14), rotary piston means (3) having three flank surfaces (26, 27, 28) and rotatably received in the housing on an eccentric portion (5) of a crank shaft (4), one of said flank surfaces always being in engagement with at least one of said transition edges, cooperative mating gear means (26A, 30) on said housing and piston means to control rotation of said piston means and a gas inlet (42) and outlet (41) to each of said lobes. Sealing fluid (90) is admitted between the rotor means and housing. The housing sidewall and piston flank surfaces may be composed of a series of parallel planar surfaces (11A, 26A, 28A) and valve plate means (51, 71, 78, 83) may control the fluid to the gas inlets. The device may operate as a compressor, expander, or vacuum pump.

Description

TR0CH0IDAL GAS PROCESSING DEVICES

DESCRIPTION

TECHNICAL FIELD

The present invention relates to rotary devices for the evacuation, compression, or expansion of compressible expandable fluids.

Devices within the scope of the present invention are useful in the recovery of work energy from the expansion of compressed gases, for example from the expansion of compressed natural or other gases, where it is necessary to reduce the pressure of the fluid for use in subsequent applications. Additionally, devices within the scope of the present invention have been found particularly useful for the compression of expansible-compressible fluids as well as the evacuation of expansible compressible fluids from selected areas.

Prior art devices related to the reduction of the pressure of fluids have generally utilized means that do not provide useful energy or which, in some instances, require energy for pressure reduction.

Various prior art means are known for obtaining useful energy through pressure reduction, the most common being turbines or other devices intended to provide useful energy from steam or other high pressure fluids where the pressure of the fluid is reduced in g passing through the device such devices generally operate with high temperature working fluids.

An example of a trochoid type rotary piston arrangement used as an expansion device shown in U.S. Patent No. 4,047,856 Hoffmann where the fluid stream to be reduced in pressure transmitted through a rotor to a 0 passageway means in the working areas of the device.

A second device is shown in U.S. Patent No. 4,540,335 Duffy where rotating valves are provided to regulate supply of gas to the epitrochoidal cavity and a shaft is fixed to a piston which rotates in planetary _5 path to periodically come into alignment with inlets in one end wall of the cavity.

In general prior art trochoid devices have required a reversal or sharp change in direction of flow of fluid through the device and thus are less efficient than devices where fluid flows through the 0 device without reversal.

Prior art devices and devices within the scope of the present invention utilize peritrochoid which is the basic curve forming the inner surface of the rotor • housing is the actual base for the geometric 5 construction of the rotary engine. The equation of peritrochoid is x=e cos +R cos /m y=e sin +R sin /m for the X and Y coordinates of the rotor. Present devices within the scope of the present invention use the trochoid of m=3, the equation of which is expressed, as: x=e cos +R cos /3 y=e sin +R sin /3 Where: e: center distance between a Base

Circle and a Rolling Circle

R: length of arm fixed on Rolling

Circle B a: angle of rotation of Revolving

Circle B around Base Circle A

In the prior art the curve used for the inner surface of the housing is a trochoid that has been moved outward- in parallel by a constant amount to accomodate the rotor which in the prior art require mechanical apex seals. Prior art devices have not taught, or even suggested, labyrinth sealing means to prevent the loss of power due to "blow-by" between rotor cavity which in accordance with the present invention allow the use of a rotor and cavity which are the reverse of each other NOT TO BE TAKEN INTO CONSIDERATION FOR THE PURPOSES OF INTERNATIONAL PROCESSING (See Section 309(c) (ii) OF THE ADMINISTRATIVE INSTRUCTIONS)

DISCLOSURE OF THE INVENTION

The present invention provides positive displacement controlled rate expansion and compression ₅ of a trochoidal rotary piston device for use in pressure reduction or in compression of expandable compressible fluids where the efficiency of the device is substantially improved to permit the recovery of significant portion of available energy when the device is used as pressure reduction device, and to provide a

10 efficient means of evacuating gas from a given area when the device is used as a vacuum source, and provides a highly efficient and effective compression device with high compression ratio.

Devices within the scope of the present invention _jc can be adapted to provide a labyrinth seal arrangement between the surface of the trochoid housing and the rotating piston where a sealing fluid can be convenientl ^'utilized around the apices of the rotating piston so that there is no contact between the lateral wall of the associated cavity and the rotor, to which 0 it has been found prolongs the life of the device and provides an efficient seal between the rotor and the cavity lateral wall to facilitate the accomplishment of the particular objectives for which the devices are . intended.

5 More particularly, the present invention provides a compressible expansible fluid handling device utilizing the rotary trochoid principal to move a gas from one area to another and change the pressure of the gas in transit thereby producing shaft horsepower. In examples in accordance with the present invention first and second ports are provided to an epitrochoidal cavity having a continuous lateral wall defined by a series of planar surfaces which effectively form a labyrinth seal where a seal is provided between the apices of a rotor which defines a sealing edge utilized with a lubricant/sealant to isolate the lobes of the cavity as the rotor turns and where in some instances the shape of rotor is the mathematical/geometrical inverse of the shape of the cavity so that the apices and faces of the rotor are in continuous contact with the cavity housing. It has been found that devices within the scope of the present invention can be easily designed to accommodate the normal expansion and contraction of the elements of the devices in response to changes in temperature of the fluid passing through the device and to eliminate the mechanical apex and lateral seals utilized in the prior art devices and yet provide a highly efficient sealing arrangement to prevent loss gases by "blow-by". 7

Even more particularly, the present invention provides a trochoid type rotary piston gas handling device including a stationary housing having side walls defining an epitrochoidal cavity symmetrical about a first axis transverse to the end walls, where the epitrochoidal cavity includes two lobes which intersect at transition edges generally parallel to the first axis, a rotatable crank shaft extending through the cavity parallel to the first axis and having a eccentric portion located on the shaft where the rotary piston is mounted on the eccentric portion of the shaft so that the axial center line of the piston describes a circular path of selected diameter around the first axis diameter during rotation thereof and where the rotary piston includes flank surfaces which intersect at apices to determine lines of sealing contact with- the walls of the cavity and where at least one of the flank surfaces is always in contact with one of the transition edges and where the walls of cavity are composed of series of planar surfaces so that as the apices travel with movement of the rotary piston the apices approach the intersection between adjacent planar sections and then move away from the planar section which is next in line in the direction of rotation and again approach the intersection of the next planar surfaces. Two inlets are provided to the stationary housing to admit compressible expansible fluid into the chamber of the trochoidal cavity and the surface of the piston where by proper modifications of the inlet, for example by use of check valves, the device can be operated as a compressor, expander or vacuum source.

In accordance with one example of the present invention a rotary valve member can be provided outside the housing to be rotated by the shaft and has a valve for communicating with a supply of the fluid to be processed where the port periodically comes into alignment with an inlet to the cavity to sequentially open and close the inlet for selected periods to selectively regulate the amount of fluid admitted to the chamber in accordance with the position of the piston surface.

With reference to arrangements within the scope of the present invention which are illustrated in the accompanying drawings it will be understood that the illustrations presented herewith and the descriptions given herein are by way of example only and that various other arrangements also within the scope of the present invention will occur to those skilled in the art upon reading the disclosure set forth hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is an exploded perspective view of one arrangement within the scope of the present invention;

Figure 2 is an elevation view in cross section of an assembled device as shown in Figure 1;

Figures 3A-3C are sequential examples of the operation of the device as shown in Figures 1 and 2;

Figures 4A, 4B are an enlarged drawing illustrating one principal of devices within the scope of the present invention;

Figures 5A, 5B present cross section diagrammatic elevational views of gas inlet and Outlet arrangement within the scope of the present invention;

Figure 6 is an elevational view of a device within the scope of the present invention used as a vacuum device or compressor;

Figure 7 is a view taken along a plane passing through lines 7-7 of Figure 6;

Figure 8 is an illustration of a device within the scope of the present invention used as an expansion device;

Figure 9 is a view taken along a plane passing through lines 9-9 of Figure 8.

Figure 10A-10D Illustrates another arrangement • within the scope of the present invention where the device is used as a gas expansion; and Figure 11A-11B shows another arrangement within the scope of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to Figure 1 a housing 1 is shown having an epitrochoidal cavity 2 including two lobes 11 and 12 as is known in the art. A rotor 3 is provided to be received in lobes 11 and 12 and further adapted to receive a crank shaft 4. Crank shaft 4 carries an eccentric lobe 5.

A pair of end walls 7 and 8 are provided to be received on opposite sides of housing 1 to define endwalls of cavity 2. Cavity 2 is generally symetrical with respect to the axis of shaft 4 where it is known in the art, cavity 2 includes a pair of epitrochoidal lobes 11 and 12 which intersect at lobe transition edges 13 and 14 to define the minor axis of the housing. Endwalls 7 and 8 are secured to housing 1 and in the example shown bolts 16 are provided in to be ^• received through cooperative apertures of sidewall and extend therethrough to be received in cooperative apertures 18 of endwall 7 to secure endwalls 7, and 8 to having 1 as shown in the arrangement of Figure 2. Endcaps 19 and 36 are provided with flanges 36A and 19A as shown which are connected through aperture 37 of endwall 7 by bolts 16A as shown in Figure 2. Housing 1 is provided with inlets 41 for admission of gas as shown by arrows A and outlets 42 for exhaust of gas from housing 1 as shown by arrows B. An inlet 2B is provided in cap 36 for admission of fluid to the device. Shaft 4 is mounted within end cap 36 in a bearing 22 which can be carried by cap 36. Seals, for example, 0 rings 23 or other means can be provided within bearing 22 to seal the shaft.

Shaft 4 includes an eccentric member 5 as previously described having a generally cylindrical outer surface which is circular in transverse section and is concentric about a second asis (not shown) parallel to and selectively spaced from the axis of shaft 4. As is known in the art the offset between the second axis and the axis of the crankshaft determines the eccentricity of the rotor in its rotation in housing 1. Rotor 3 is symetrical about its axis, as is known in the art so that rotor 3 and eccentric 5 are concentric with their center axis being regularly displaced from the longitudinal axis of power shaft 4 a selected distance to provide an orbital rotation diamenter.

Rotor 3 can be smooth or can be formed by labyrinth construction as discussed hereinafter and epitrochoidal flank surfaces 26-28 which intersect at apices A, B, C. The apices A, B and C, the surfaces - 26-28 and the walls of housing 1 define a plurality of moving chambers within the cavity of housing 1 as rotor 3 turns. An inner bearing 30 having teeth 30A to be received in teeth 3A of rotor 3 is provided where bearing 30 has an inner cylindrical surface 29 to support bearing 30 on the eccentric 5 of shaft 4 for rotation as the teeth 30A mesh with teeth 3A to rotate rotor 3. Rotor 3 is provided with opposite generally parallel facing surfaces which are disposed to engage the inner surface of end walls 7 and 8 to receive a lubricant/sealing fluid to provide a seal there between, as described hereinafter.

In assembled form three chambers are defined within housing 1 by the inner walls of cavity 2 and the flank surfaces 26, 27 and 28 of rotor 3. Second cap 19 can be provided at the end of housing 1 opposite housing 19 and can be secured to endwall 7 as previously described. A second bearing 38 is provided endwall 8, to journal the second end of shaft 4 and can include "0" ring or other seal means 39 to seal on shaft 4.

Housing 1 can include gas inlet 42 in appropriate position within the housing as determined by the characteristics of the operation of the device. Gas outlets 41 are provided from lobes 11 and 12 of housing

1 and are positioned in diametrically opposed relations through a centerline of shaft 4. Each of the lobes 11 and 12 includes an inlet ports 42 respectively for admission of fluid and conduits respectively connecting the inlet with the inside of chamber 2 as shown in

Figures 3A-3C.

Figures 1, 2, and 3A-3C illustrate one means for admitting gas to housing 1. Alternative means are also available as described hereinafter depending upon the mode of operation within the scope of the present invention, for example where the device is to be operated as a gas expander valve means can be provided to selectively admit gas to housing 1 and to control the quantity of gas admitted.

While devices within the scope of the present invention can be used for various applications such as gas compressor or vacuum device, in one application of the device within the scope of the present invention as shown in Figure 8, 9 10A-10D, and 11A, 11B the device be used for gas expansion.

While the epitrochoidal principal of operation is known in the art, it will be noted that rotor 3, in general includes an internal ring gear 26A and endwall 7 includes a planetary gear 30 of smaller diameter.

The gears are located in cooperative relation to provide proper phasing between the rotation of shaft 4 the position of eccentric 5 and the rotation of rotor

3, to insure that the apices A, B and C of rotor 3 are in contact with the portion of the inner surface of epitrochoidal cavity 2 at all times during operation of the unit. To maintain such contact the gears have a specific relationship one to another and a specified

b _ relationship to the eccentricity of the rotor. This relationship is described in detail in the prior art for an epitrochoidal cavity with two lobes and a rotor with three apices requires specific pitch diameter of the inner ring gear, namely six times the eccentricity between the axis of shaft 4 and the axis of lobe 6 and pitch diameter of the stationary gear 10 to be four times the eccentricity of the rotor. Also, as is known in the art the ring gear pitch diameter is li times the planetary gear pitch diameter and , thus, must include li times as many gear teeth. Accordingly, in , _f. operation the shaft 4 rotates faster than lobe 3 and in the arrangement shown the shaft 4 rotates three times' faster than the speed of rotation of rotor 3.

Accordingly in the arrangement shown, for every rotation of rotor 26 shaft 4 will accomplish three rotations. This arrangement is illustrated in Figure 0 3A-3C discussed hereinafter.

In operation of the device of the type shown in Figures 1 and 2, clearances and sealing characteristics are of utmost importance. Most prior art devices have .been designed to operate at specific high temperatures 5 range and have been provided with apex seals. In accordance with the present invention it has been found that utilizing devices for compression, vacuum and expansion where lower temperature gasses are present effective sealing can be accomplished by shaping the elements in accordance with the present invention as discussed hereinafter and by introducing sealing fluid or lubricant of selected viscosity/temperature characteristics to the moving parts with elimination of the previously required complex mechanical seal and lubrication arrangements. An example of an inlet for the sealing/lubricating fluid is shown in Figure 2 where a conduit 90 is show to admit fluid to the cavity from a source not shown.

Figures 5A and 5B illustrate a seal and rotor movement arrangement for a portion of a cycle. In Figure 5A rotor 3 is in position with apex A engaging^" the surface of lobe 12 at point D, surface 26 engaging the transition between lobes 11 and 12 at point E and apex C engaging the surface of lobe 11 at F.

Gas is admitted through inlet 41 to the chamber G found between lobe 11 and surface 26 while gas is also being withdrawn from chamber H formed between surface 26 and lobe 12 as rotor 3 moves in the direction illustrated by arrow 70.

It will be understood that regardless of the application for which the device in utilized, that is for compression or as a vacuum source where shaft 4 is driven by a power source, or as a gas expander where shaft 4 is driven by the expansion of gas in the device sealing of the chambers is important and the characteristics shown in Figures 5A, 5B occur and are enhanced by fabrication of the elements as discussed with reference to figure 4A and 4B.

Figure 5A also illustrates the use of a sealing fluid which is supplied to housing 1 by any convenient

10 feed means as previously described and which moves around the housing in response to movement of rotor 3 to form the liquid seals 60 as shown in Figure 5A, 5B wherever an apex of rotor 3 approaches the inner surface of lobes 11 and 12. ,,. In Figure 5A, 5b an inlets 90 are provided for admission of metered quantities of sealing fluid into the gas passing throught inlets 42.

Referring now to Figure 5B which illustrates the orientation of the elements after further rotation of rotor 3 in the direction of arrow 70 where apex A 0 engages transistion part E, with a seal 60 and where gas is flowing from chamber I through outlet 42.

One salient feature in accordance with the present invention is illustrated in Figures 4A and 4B, where .the surfaces 26 and 28 of rotor 3 and the surface of 5 lobe 11 are presented as representative of the surfaces of the balance of the corresponsing elements, it has been unexpectedly found that if the surfaces of the elements are composed of straight segments 11A, 26A and 28A with intermediate intersections 11B, 26B, 28B the effectiveness of the fluid seals 60 is enhanced. The reasons for the enhanced sealing effect is not fully understood but is believed to be attributable, at least in part, to the additional relative motion, principally lateral, between the elements which occurs because of the interaction of the fluid with the straight segments of the elements to form a labyrinth surface.

Figures 3A-3C illustrate sequentially operation of an example of a device within the scope of the present invention.

In Figure 3A the arrangement is shown in schematic end view where rotor 3 is located in a cavity defined^' by lobes 11 and 12 which has been developed in accordance with the present invention where there is essentially no parallel transfer of its cavity and the rotor and cavity are geometric inverses. In Figure 3A rotor 3 is in a position so that a chamber is formed between the flank surface 26 and the surface of the cavity formed by the housing 1 so gas flows into the chamber from inlet 42. It will be noted that sealing is obtained between lobe 11 and flank section 26 and apex C is sealed on the inner surface of the housing. Also gas is in the process of emission through outlet

41 from the cavity defined by flank 26 and lobe 11 where apex A is sealed on lobe 12. The chamber defined by flank section 27 is in expansion and because of the seal provided by apices A and B gas is being admitted from the second inlet 4 in lobe 12 formed by flank surface 27 and the inner wall of the cavity of lobe 12.

In Figure 3B the gas in the chamber between flank surface 27 and the inner wall of lobe 12 has expanded an outlet 41 has been opened because of the movement of apex A gas is being admitted to the chamber formed by

28 by means of inlet 42.

Outlet 41 in lobe 11 has opened and gas is being emitted from the chamber defined by surface 28.

In Figure 3C surface 27 has rotated past inlet 42 in lobe 11 and gas is being admitted to the chamber • defined between surface 27 and the inner wall of lobe 11 where surface 29 is also sealed at the transition between lobes 11 and 12 and apex B is sealed on the inner surface of lobe 12 so that gas in the chamber between surface 27 and the inner wall of lobe 12 is emitted from outlet 4 in lobe 12.

It will also be noted that in each case one of the flank surfaces of rotor 3 is always in contact with one of the transition edges 13 or 14 of the cavity. It has been found that such an arrangement which is not ^~

20 present in devices having a parallel transfer factor so rotor and cavity are not in perfect inverse relation, substantially improves the effectiveness of devices within the scope of the present invention.

In accordance with another feature of the present invention as shown in Figure 1 a valve plate 51 having a single slot 56 can optionally be utilized when the device for expansion of gases to accommodate the charging of all of the chambers defined by the flank sections of rotor 3 and the lobes 11 and 12. It will be appreciated that the dimensions of slot 56 can be selected to determine the quantity of gas to be admitted to the unit for each charge and that by simply varying the position of the valve plate on the shaft or by utilizing valve plates having different length slots the speed and power generated by the device as well as the overall pressure drops through the device can be determined. • In the arrangement shown shaft 4 makes three rotations (as does valve plate 51) for each rotation of rotor 3.

Figure 8 is an illustration of a device within the scope of the present invention as shown in Figure 1 where no valve plate 51 is provided and in this respect is similar to the arrangement shown in Figure 2.

The inlet gas enters through the inlet 42 and is exhausted through outlet 41 as rotor 3 turns on the shaft 4 so that the rotor is rotated through the lobes

11 and 12.

Figure 9 is a view taken along a plane passing through the line 99 of Figure 8 illustrating and crosseσtion additional aspects of the orientation of the elements showing the endwalls 7 and 8 as well as an arrangement for the outlet 41. In arrangement shown the inlet 42 is illustrated in an alternative configuration that is shown in Figures 1 and 2 but provides equivalent operability.

Figures 6 and 7 illustrate an arrangement where a valve plate 56 is provided to rotate with shaft 54 to allow the slot 56 to come into alignment with the inlet 42 for selected admission of gases to the device. The arrangements of the types shown in Figures 6 and 7 which incorporate the valve plate as shown in Figure '1 are utilized principally where the device is to be utilized as a gas expander and where useful work is to be generated at the shaft 4 which can be used for other purposes such as the generation of electrical power, or the operation of other selected machinery requiring rotational shaft horsepower.

Figures 10A-10D illustrates another arrangement useful in connection with the operation of a device within the scope of the present invention as a gas expander. In each of the cases 10A-10C a cam valve of the type shown in Figure I0D is utilized. An example of a cam valve 71 is illustrated in Figure 10D and has a cam _ surface 74 which is utilized to block off the inlet 42 in the arrangements shown in Figures 10A-10C as described hereinafter. A space 73 is provided around the periphery of the cam 71 to admit gas to the inlet 42.

With reference now to Figure 10A the cam surface 74 is shown in position not blocking either of the inlets 42 the upper inlet 42 is in a position where gas is being admitted to a chamber defined by the portion of the rotor 3 between the apex C and the inner section 13. At the same time gas is be emitted through the ■_je outlet 41 in the chamber defined between the apex A and the inner section line 13. Likewise the apex B is located at the intersection 14 and a chamber is defined between the apex C and the apex A where gas is being emitted from the respective cavity.

In Figure 10B the valve plate has rotated to a 0 point where the cam section 74 is covering the inlet 42 while gas is being emitted from the chamber defined between the apex C and the intersection 14.

Likewise gas is being emitted from the lower .outlet 41 and admitted to the chamber defined between 5 the apex A and apex C. In Figure IOC the cam valve has rotated to the point where the cam section 74 blocks the upper inlet

42 where the rotor 3 rotates in a direction to open the upper inlet 42 and allow admission of gas for expansion as shown in Figure 10A.

A detailed drawing of an example of seal fluid inlet means is shown with reference to Figure IOC where inlet 90 is shown for admitting liquid to the gas stream admitted through inlet 42. Again, as with Figure 1 the rotor can be geared and a gear provided on the shaft so the rotor makes 3 revolutions for every rotation of the shaft. Figure 11A and 11B illustrate an alternative arrangement for admission of gas to a device of a type within the scope of the present invention where in Figures llA and 11B a cam wheel 76 is provided having a aperture 75 to receive shaft 4 and a cam section 76 is provided. Followers 78," and 83 are provided as shown and have apertures 79 and 84 in alignment with the inlets 42 for admission of gas to the unit. The _cam followers are pivoted and held in position by springs 81 and 82 respectively, as shown in Figure 11B, rotation of the cam wheel 76 causes a cam 77 to selectively engage the cam follower surface and rotate the cams to a position where, for example, the inlet 84 is out of alignment with the inlet 42 to block off the flow of gas into the unit at appropriate times.

It will be understood that the foregoing are but a few examples of arrangements within the scope of the present invention and that various other arrangements also within the scope of the present invention will occur to those skilled in the art upon reading the disclosure set forth hereinbefore.

Claims

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CLAIMS OF THE INVENTION

THE INVENTION CLAIMED IS: CLAIM 1

A trochoid-type rotary piston gas processing device including a stationary housing having a continuous sidewall defining a continuous epitrochoidal sidewall including two semicircular lobes which intersect at a pair of opposed transition diametrically edges extending generally parallel to a first axis parallel to the longitudinal axis of said cavity generally planar first and second end walls received by said housing on opposite sides of said cavity and having shaft aperture means in aligned relation on opposite sides of said housing where said cavity is symmetrical about said first axis, rotatable crank shaft means extending through said shaft apertures and said cavity parallel to said first axis and including an eccentric portion located on said shaft in said cavity, rotary piston means rotatably received on said eccentric portion of said crank shaft so that said axial centerline of said piston describes a circular path about the axis of said shaft in response to rotation of said crankshaft where said rotary piston includes three flank surfaces of generally equal length which intersect at apices to determine lines of sealing contact with said housing of said cavity and wherein 26 one of said flank surfaces of said rotor means is always in engagement with at least one of said transition edges; and wherein said housing means and said rotary piston means include cooperative mating gear means to determine the speed of rotation of said piston means relative to said position shaft means and where said rotary piston means accomplishes one revolution for every three revolutions of said shaft means; and first and second gas inlets located in generally diametrically opposed relation with respect to said axis of said shaft whereby said compressible fluid is conducted into said expansion/compression chambers defined between said trochoidal cavity and a flank surface of said piston means, outlet means provided in said housing when said piston is in selected position; a source of gas to be supplied to said outlet means. CLAIM 2-

The invention of Claim 1 including inlet means for admission of sealing fluid to the area of engagement between said rotor means and said housing.

CLAIM 3

The invention of Claim 1 wherein the said side walls of said epitrochoidal cavity are composed of a series of planar surfaces intersecting at intersection NOT TO BE TAKEN INTO CONSIDERATION FOR THE PURPOSES OF INTERNATIONAL PROCESSING (See Section 309(c) (ii) OF THE ADMINISTRATIVE INSTRUCTIONS)

CLAIM 8

The invention of Claim 1 including cam valve means rotatable with said shaft means having a base diameter with reference to said shaft and cam means extending outwardly from said base diameter where said cam means is located to engage said fluid inlet and where said cam means has a circumferential length less than i the circumference if said cam means at said base diameter. CLAIM 9

The invention of Claim 1 including valve means to be selectively opened to admit fluid to said first and second inlets where said valve means operated by follower means and cam means are provided on said shaft means to engage said follower means.

_-- CLAIM 10 15

The invention of Claim 1 wherein said rotary shaft is driven by selective motive means and wherein the pressure of fluid emitted from said device is greater than the pressure of the fluid admitted to said device.

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