Rotary Fluid Transfer Apparatus and Associated Methods

Abstract

A fluid transfer device comprising an inner member with a central axis and an outer surface; an outer member coaxially arranged with the inner member, and a space defined radially between the inner and outer members; a first and second axial members; at least one fluid chamber defined in the space having an inlet and an outlet; the first axial member is rotationally fixed relative to the outer member and the second axial member is rotatable about the central axis to vary the volume of the fluid chamber. The relative rotational position of the first and second axial members is defined by a cam arrangement which comprises first and second axial member walls; the first axial member wall forms a first cam track wall which provides a first cam track waveform, the second axial member wall which comprises a second cam track wall; each cam track wall is circumferentially continuous.

Claims

1. A motor comprising: an inner member with a central axis and comprising an outer surface; an outer member arranged co-axially with the inner member and comprising an inner surface radially spaced from the outer surface of the inner member to define a space between the inner and outer members; a first axial member; a second axial member; at least one fluid chamber defined in the space; a fluid inlet to the at least one fluid chamber, and a fluid outlet from the at least one fluid chamber, wherein the volume of the fluid chamber is variable such that variance in the volume of the fluid chamber acts to move at least one of the first and second axial members about the central axis to produce a mechanical output.

2. A motor as claimed in claim 1 wherein the volume of the at least one fluid chamber is variable in response to a fluid pressure.

3. A motor as claimed in claim 1 wherein the at least one fluid chamber volume is variable in response to a fluid pressure differential.

4. A motor as claimed in claim 3 wherein the fluid pressure differential is a differential fluid pressure across the inlet and the outlet.

5. A motor as claimed in claim 1 wherein the motor is an engine.

6. A motor as claimed in claim 1 wherein the motor is a combustion engine.

7. A motor as claimed in claim 6 wherein at least a portion of the at least one fluid chamber comprises a combustion chamber.

8. A motor as claimed in claim 7 wherein the at least one fluid chamber volume varies in response to a change in internal chamber pressure.

9. A motor as claimed in claim 6 wherein the at least one outlet may comprise an exhaust outlet.

10. A motor as claimed in claim 1 wherein the volume of the at least one fluid chamber corresponds to an axial position of the first and/or second axial members.

11. A motor as claimed in claim 10 wherein the axial position comprises an axial separation.

12. A motor as claimed in claim 1 wherein the motor comprises a rotor.

13. A motor as claimed in claim 1 wherein the second axial member comprises a rotor.

14. A motor as claimed in claim 1 wherein the second axial member comprises a piston head.

15. A motor as claimed in claim 1 wherein the motor comprises a stator.

16. A motor as claimed in claim 1 wherein the first axial member comprises a stator.

17. A motor as claimed in claim 1 wherein the first axial member comprises a cylinder.

18. A motor as claimed in claim 1 wherein an axial position/s of the first and/or second axial member/s may correspond a rotational position of the first and/or second axial member/s respectively.

19. A motor as claimed in claim 1 wherein the mechanical output is a rotational movement.

20. A motor as claimed in claim 1 wherein the mechanical output is a linear axial movement.

21. A method of generating a motorised mechanical output, the method comprising: providing an inner member with a central axis and comprising an outer surface; providing an outer member arranged co-axially with the inner member and comprising an inner surface radially spaced from the outer surface of the inner member; defining a space between the inner and outer members; providing a first axial member; providing a second axial member; defining at least one fluid chamber in the space; providing a fluid inlet to the at least one fluid chamber, and providing a fluid outlet from the at least one fluid chamber, varying the volume of the fluid chamber such that variance in the volume of the fluid chamber acts to move at least one of the first and second axial members about the central axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0286] These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0287] FIG. 1 shows a perspective view of a portion of a fluid transfer device in accordance with a first embodiment of the invention;

[0288] FIG. 2 shows a plan view of the fluid transfer device of FIG. 1;

[0289] FIG. 3 shows the fluid transfer device of FIG. 1 in a first rotational position;

[0290] FIG. 4 shows the fluid transfer device of FIG. 1 in a second rotational position;

[0291] FIG. 5 shows the fluid transfer device of FIG. 1 in a third rotational position;

[0292] FIG. 6 shows the fluid transfer device of FIG. 1 in a fourth rotational position;

[0293] FIG. 7 shows a perspective view of a portion of a fluid transfer device in accordance with a second embodiment of the invention;

[0294] FIG. 8 shows a plan view of the fluid transfer device of FIG. 7;

[0295] FIG. 9 shows the fluid transfer device of FIG. 7 in a first rotational position;

[0296] FIG. 10 shows the fluid transfer device of FIG. 7 in a second rotational position;

[0297] FIG. 11 shows the fluid transfer device of FIG. 7 in a third rotational position;

[0298] FIG. 12 shows the fluid transfer device of FIG. 7 in a fourth rotational position;

[0299] FIG. 13 shows a plan view of a fluid transfer device in accordance with a third embodiment of the invention;

[0300] FIG. 14 shows a partial view of the fluid transfer device of FIG. 13 in a first rotational position;

[0301] FIG. 15 shows a partial view of the fluid transfer device of FIG. 13 in a second rotational position;

[0302] FIG. 16 shows a partial view of the fluid transfer device of FIG. 13 in a third rotational position;

[0303] FIG. 17 shows a partial view of the fluid transfer device of FIG. 13 in a fourth rotational position;

[0304] FIG. 18 shows a partial view of the fluid transfer device of FIG. 13 in a fifth rotational position;

[0305] FIG. 19 shows a partial view of the fluid transfer device of FIG. 13 showing external porting in the first rotational position of FIG. 14;

[0306] FIG. 20 shows a partial view of the fluid transfer device of FIG. 13 showing external porting in a first intermediate rotational position;

[0307] FIG. 21 shows a partial view of the fluid transfer device of FIG. 13 showing external porting in a second intermediate rotational position;

[0308] FIG. 22 shows a partial view of the fluid transfer device of FIG. 13 showing external porting in a third intermediate rotational position;

[0309] FIG. 23 shows a partial view of the fluid transfer device of FIG. 13 showing external porting in the third rotational position of FIG. 16;

[0310] FIG. 24 shows a partial view of the fluid transfer device of FIG. 13 showing external porting in a fourth intermediate rotational position;

[0311] FIG. 25 shows a partial view of the fluid transfer device of FIG. 13 showing external porting in the fifth rotational position of FIG. 18;

[0312] FIG. 26 shows a partial view of the fluid transfer device of FIG. 13 showing internal porting in the third rotational position of FIGS. 16 and 23;

[0313] FIG. 27 shows a plan view of the fluid transfer device of FIG. 13 corresponding to the rotational position of FIG. 26 and indicating the direction of view shown in FIG. 26;

[0314] FIG. 28 shows a partial view of the fluid transfer device of FIG. 13 showing internal porting in the second rotational position of FIGS. 16, 23, 26 and 27, viewed from a direction at 90 from FIG. 26;

[0315] FIG. 29 shows a plan view of the fluid transfer device of FIG. 13 corresponding to the rotational position of FIG. 28 and indicating the direction of view shown in FIG. 28;

[0316] FIG. 30 shows a partial view of the fluid transfer device of FIG. 13 showing internal porting in a fifth intermediate position viewed from a similar direction to FIG. 28;

[0317] FIG. 31 shows a plan view of the fluid transfer device of FIG. 13 corresponding to the rotational position of FIG. 30 and indicating the direction of view shown in FIG. 30;

[0318] FIG. 32 shows a plan view of a fluid transfer device in accordance with a fourth embodiment of the invention;

[0319] FIG. 33 shows a partial view of the fluid transfer device of FIG. 32;

[0320] FIG. 34 shows a path showing the movement of a cam follower of the device of FIG. 32;

[0321] FIG. 35 shows a partial view of the fluid transfer device of FIG. 32 in a first rotational position;

[0322] FIG. 36 shows a partial view of the fluid transfer device of FIG. 32 in a second rotational position;

[0323] FIG. 37 shows a partial view of the fluid transfer device of FIG. 32 in a third rotational position;

[0324] FIG. 38 shows a partial view of the fluid transfer device of FIG. 32 in a fourth rotational position;

[0325] FIG. 39 shows a partial view of the fluid transfer device of FIG. 32 in a fifth rotational position;

[0326] FIG. 40 shows a partial view of the fluid transfer device of FIG. 32 showing external porting in the first rotational position of FIG. 35;

[0327] FIG. 41 shows a partial view of the fluid transfer device of FIG. 32 showing external porting in a first intermediate rotational position;

[0328] FIG. 42 shows a partial view of the fluid transfer device of FIG. 32 showing external porting in the second rotational position of FIG. 36;

[0329] FIG. 43 shows a partial view of the fluid transfer device of FIG. 32 showing external porting in the third rotational position of FIG. 37;

[0330] FIG. 44 shows a partial view of the fluid transfer device of FIG. 32 showing external porting in a second intermediate rotational position;

[0331] FIG. 45 shows a partial view of the fluid transfer device of FIG. 32 showing external porting in the fourth rotational position of FIG. 38;

[0332] FIG. 46 shows a partial view of the fluid transfer device of FIG. 32 showing external porting in the fifth rotational position of FIG. 39;

[0333] FIG. 47 shows a view of a fluid transfer device in accordance with a fifth embodiment of the invention in a first rotational position;

[0334] FIG. 48 shows a partial view of the fluid transfer device of FIG. 47 in a second rotational position;

[0335] FIG. 49 shows a partial view of the fluid transfer device of FIG. 47 in a third rotational position;

[0336] FIG. 50 shows a partial view of the fluid transfer device of FIG. 47 in a fourth rotational position;

[0337] FIG. 51 shows a partial view of the fluid transfer device of FIG. 47 in a fifth rotational position;

[0338] FIG. 52 shows a partial view of the fluid transfer device of FIG. 47 in a sixth rotational position;

[0339] FIG. 53 shows a partial view of the fluid transfer device of FIG. 47 in a seventh rotational position;

[0340] FIG. 54 shows a view of a fluid transfer device in accordance with a sixth embodiment of the invention in a first rotational position;

[0341] FIG. 55 shows the device of FIG. 54 within a cylinder casing;

[0342] FIG. 56 shows a cross section of the device of FIG. 55 in a first rotational position;

[0343] FIG. 57 shows a cross section of the device of FIG. 55 in a second rotational position;

[0344] FIG. 58 shows a cross section of the device of FIG. 55 in a third rotational position;

[0345] FIG. 59 shows a perspective partial view of a fluid transfer device in accordance with a seventh embodiment of the invention;

[0346] FIG. 60 shows the device of FIG. 59 within a cylinder casing;

[0347] FIG. 61 shows a perspective partial view of a fluid transfer device in accordance with an eighth embodiment of the invention;

[0348] FIG. 62 shows the device of FIG. 61 within a cylinder casing

[0349] FIG. 63 shows a partial cut-away side view of an apparatus in accordance with a ninth embodiment of the invention comprising two devices of FIG. 61 in a first rotational position;

[0350] FIG. 64 shows the apparatus of FIG. 63 with in a second rotational position;

[0351] FIG. 65 shows a cross section of the apparatus of FIG. 63;

[0352] FIG. 66 shows a cross section of the apparatus of FIG. 64;

[0353] FIG. 67 shows a partially exploded view and a partial cut-away assembled view of an apparatus in accordance with a tenth embodiment of the invention;

[0354] FIGS. 68 and 69 show an assembled portion of the apparatus of FIG. 67 in a minimum chamber volume configuration;

[0355] FIGS. 70 and 71 show the assembled portion of the apparatus of FIG. 67 in an intermediate configuration;

[0356] FIGS. 72 and 73 show the assembled portion of the apparatus of FIG. 67 in a maximum chamber volume configuration;

[0357] FIGS. 74 and 75 show the assembled portion of the apparatus of FIG. 67 in an intermediate chamber volume configuration;

[0358] FIGS. 76 and 77 show the assembled portion of the apparatus of FIG. 67 in the minimum chamber volume configuration;

[0359] FIG. 78 shows a partial cross-sectional detail of the portion of the apparatus of FIG. 67;

[0360] FIGS. 79 to 81 show a greater portion of the apparatus of FIG. 67 in sequential configurations;

[0361] FIG. 82 shows a portion of an eleventh embodiment of the present invention of an apparatus with a plurality of devices;

[0362] FIG. 83 shows a portion of a path of an aperture in a projection of the device of FIG. 82 relative to an inlet.

[0363] FIGS. 84 to 88 show relative positions of inlets, outlets, openings or apertures in first and second inner members of the portion of the apparatus of FIG. 82.

[0364] FIGS. 89 to 104 show a portion of an apparatus according to a twelfth embodiment of the present invention, with the portion of the apparatus shown in sequential configurations;

[0365] FIGS. 105 to 113 show cross-sectional views of the portion of the apparatus of FIGS. 89 to 104.

DETAILED DESCRIPTION OF THE DRAWINGS

[0366] Referring initially to FIG. 1, there is shown a fluid transfer device, generally designated 10, in accordance with an embodiment of the present invention having an inner member 46 with a central axis 28 and comprising an outer surface 48. The device 10 has an outer member 42 coaxially arranged with the inner member 46 and comprising an inner surface 44 radially spaced from the outer surface 48 of the inner member 46 to define a space between the inner and outer members 46, 48. The device 10 comprises a first axial member comprising a cam track 12 and a second axial member comprising a cam follower 14 and at least one variable fluid chamber 20 defined in the space. The device 10 has a fluid inlet 22 to the at least one fluid chamber 20; and a fluid outlet 24 from the at least one fluid chamber 20. At least one of the first and/or second axial member/s is rotatable about the central axis 28 to vary the volume of the at least one fluid chamber 20. In the embodiment shown, the second axial member comprising the cam follower 14 is rotatable. The volume of the at least one fluid chamber 20 corresponds to a rotational position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12.

[0367] In the embodiment shown, the chamber 20 is disposed between the first axial member comprising the cam track 12 and the second axial member comprising the cam follower 14. The second axial member comprising the cam follower means is adapted to run in the first axial member comprising the cam track 12, following a path. The space shown is an annular space.

[0368] The first axial member comprising the cam track 12 comprises a first cam track wall means 16 and the second axial member comprising the cam follower 14 comprises a first cam follower means 18, and the first cam track wall means 16 and the first cam follower wall means 18 face one another.

[0369] The device comprises a fluid chamber 20 disposed between the first axial member comprising the cam track 12 and the second axial member comprising the cam follower 14. The device 10 further comprises a fluid inlet 22 to the fluid chamber 20; and a fluid outlet 24 from the fluid chamber 20.

[0370] The first axial member comprising the cam track 12 and the second axial member comprising the cam follower 14 are coaxially arranged. In the embodiment shown, the second axial member comprising the cam follower 14 is configured to rotate about a central axis 28. The first axial member comprising the cam track 12 defines a rotational path about the central axis 28 for the second axial member comprising the cam follower 14.

[0371] A volume of the fluid chamber 20 corresponds to a rotational position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12. A volume of the fluid chamber 20 corresponds to an axial position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12. In the embodiment shown, the second axial member comprising the cam follower 14 comprises a rotor 17; and the first axial member comprising the cam track 12 comprises a stator 13.

[0372] In the embodiment shown, the device 10 is a pump. However, it will be readily appreciated, that in alternative embodiments, a motor of similar features may function in a substantially opposite mode of operation. A volume of the fluid chamber 20 varies in response to a mechanical input. The volume of the fluid chamber 20 varies in response to a rotation of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12. The device 10 is a downhole device configured to transfer a bore fluid, which is a hydrocarbon from a reservoir (not shown).

[0373] The first cam track wall means 16 provides a first cam track wave or waveform 30. The first cam follower wall means 18 provides a first cam follower wave or waveform 32.

[0374] In use, the first cam track wall means 16 and first cam follower wall means 18 selectively abut, strike, ride over or upon, slide relative to, and/or contact one another. In this way the first cam track wall means 16 and first cam follower wall means 18 interact with or upon one another such that at least part of a motion (e.g. rotational motion) of the second axial member comprising the cam follower 14 defines at least part of a motion (e.g. longitudinal motion) of the first axial member comprising the cam track 12 or vice versa. In use, the first cam track wall means 16 and the first cam follower wall means 18 contact one another such as to form a continuous dynamic seal therebetween.

[0375] The inlet 22 and outlet 24 are bidirectional, in the form of ports. In alternative embodiments, the inlet/s and/or outlet/s may be unidirectional, such as one way valves.

[0376] The first cam track wall means 16 shown is rotationally or circumferentially continuous. The first cam track wave 30 comprises a periodic waveform. In FIG. 1, the first cam track wall means 16 comprises a sloped (wedge-shaped) form. The first cam track wave 30 comprises a substantially sinusoidal waveform with a rotational period of 1 (i.e. there is one complete wave around 360).

[0377] In the embodiment shown, the first cam follower wave or waveform 32 is an inverted form of the first cam track wave or waveform 30. Accordingly, the first cam follower wall means 18 shown is rotationally or circumferentially continuous. The first cam follower wave 32 comprises a periodic waveform. In FIG. 1, the first cam follower wall means 18 comprises a sloped (wedge-shaped) form. The first cam follower wave 32 comprises a substantially sinusoidal waveform with a rotational period of 1 (i.e. there is one complete wave around 360).

[0378] The device 10 comprises an outer (longitudinal) member 42. The outer member 42 forms a housing for the first axial member comprising the cam track 12 and the second axial member comprising the cam follower 14. An inner wall 44 of the outer member 42 defines an outer wall of the fluid chamber 20. The outer member 42 is configured to connect to an external apparatus, such as a casing, liner, coiled tubing, tubular, drillstring or the like (e.g. the outer member 42 comprises a box or screw connection, not shown).

[0379] The device 10 comprises an inner (longitudinal) member 46. An outer wall 48 of the inner member 46 defines an inner wall of the fluid chamber 20. The inner member 46 is a hollow shaft with a throughbore 50 in the embodiment shown. The inner member 46 is configured to connect to an external apparatus, such as a toolstring, coiled tubing, tubular, slickline, wireline, motor or the like (not shown).

[0380] The inner and outer members 42, 46 are coaxially and concentrically arranged about the central axis 28, as shown in FIG. 2. The inner and outer members 42, 46 are relatively rotatable about the central axis 28. The inner and outer members 42, 46 are relatively axially movable.

[0381] The fluid chamber 20 comprises an annular fluid chamber, which is a portion of an annulus between the inner and outer members 42, 46.

[0382] The inlet 22 and outlet 24 are substantially radially arranged. The device 10 is configured to transfer fluid substantially radially. The inlet 22 is located in the outer member 42. The outlet 24 is located in the inner member 46. The device 10 is configured to transfer fluid between an annulus outside the outer body 42 and the throughbore 50.

[0383] The second axial member comprising the cam follower 14 is rotationally fixed relative to the inner member 46. The second axial member comprising the cam follower 14 is rotatable with the inner member 46. The first axial member comprising the cam track 12 is rotationally fixed relative to the outer member 42.

[0384] The second axial member comprising the cam follower 14 is axially moveable relative to the inner member 46. The first axial member comprising the cam track 12 is axially fixed to the outer member 42. The second axial member comprising the cam follower 14 is axially movable relative to the outer member 42. The second axial member comprising the cam follower 14 is relatively axially movable so as to ensure axial contact between the first cam track wall means 16 and the first cam follower wall means 18. The second axial member comprising the cam follower 14 is relatively axially urged. For example, the cam follower is axially urged by a fluid pressure (e.g. acting as a piston). For example, the second axial member comprising the cam follower 14 may be axially driven by an adjacent second device (not shown); such as with an opposing fluid chamber above the second axial member comprising the cam follower 14 (e.g. the second axial member comprising the cam follower 14 may comprise a cam follower for a mirrored second device, not shown). The second axial member comprising the cam follower 14 is fixed to the inner member 46.

[0385] The device 10 is configured to selectively open and close the inlet 22 and the outlet 24. The second axial member comprising the cam follower 14 is configured to selectively open and close the inlet 22 and the outlet 24 according to a relative rotational position. As shown in FIG. 3, a first rotational position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12 corresponds to an closed position of the inlet 22 and an opening position of the outlet 24. A second rotational position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12 (FIG. 4) corresponds to a closing position of the inlet 22 and a closed position of the outlet 24. A third rotational position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12 (FIG. 5) corresponds to an open position of the inlet 22 and a closed position of the outlet 24. A fourth rotational position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12 (FIG. 6) corresponds to a closed position of the inlet 22 and an open position of the outlet 24. The respective rotational positions shown in FIGS. 3 to 6 are separated by 90 rotations of the second axial member comprising the cam follower 14 with the inner member 46. Accordingly, it will be appreciated that fluid is pumped from the outlet 22 through the chamber 20 via the inlet 24 to the throughbore 50 by the sequential rotation between the respective rotational positions, as detailed below. It will also be appreciated that in alternative embodiments, or alternative modes of operation, a similar device may function as a pump for transferring fluid from the throughbore 50 through the chamber and out through the inlet 22 (i.e. the inlet 22 would function as an outlet and the outlet 24 would function as an inlet), such as by reversing the direction of relative rotation.

[0386] A rotational position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12 corresponds to a specific volume of the fluid chamber 20. A rotational position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12 corresponds to an increasing or a constant or a decreasing volume of the fluid chamber 20. A rotational position of the second axial member comprising the cam follower 14 relative to the first axial member comprising the cam track 12 corresponds to an axial position of the second axial member comprising the cam follower 14 relative to the cam track.

[0387] The device is configured to selectively open the inlet 22 according to a rotational position of the second axial member comprising the cam follower 14 relative to the cam track. The device is configured to selectively maintain the inlet 22 open according to a rotational position of the second axial member comprising the cam follower 14 relative to the cam track. The device is configured to selectively close the inlet 22 according to a rotational position of the second axial member comprising the cam follower 14 relative to the cam track. The device is configured to selectively maintain the inlet 22 closed according to a rotational position of the second axial member comprising the cam follower 14 relative to the cam track.

[0388] The second axial member comprising the cam follower 14 is configured to open the inlet 22 when the second axial member comprising the cam follower 14 is rotated to a position corresponding to a minimum fluid chamber 20 volume (FIG. 3). The second axial member comprising the cam follower 14 is configured to maintain the inlet 22 open when the second axial member comprising the cam follower 14 is rotating relative to the first axial member comprising the cam track 12 such that the fluid chamber 20 volume is increasing (e.g. between FIGS. 3 and 5). Accordingly, the second axial member comprising the cam follower 14 maintains the inlet 22 open when underpressure in the fluid chamber 20 is created or present (FIGS. 4 and 5). Accordingly, fluid is drawn into the fluid chamber 20 through the inlet 22. The second axial member comprising the cam follower 14 is configured to close the inlet 22 when the second axial member comprising the cam follower 14 is rotated to a position corresponding to a maximum fluid chamber 20 volume (FIG. 5). The second axial member comprising the cam follower 14 is configured to maintain the inlet 22 closed when the second axial member comprising the cam follower 14 is rotating relative to the first axial member comprising the cam track 12 such that the fluid chamber 20 volume is decreasing (between FIG. 5 and FIG. 6 and between FIG. 6 and starting a new rotation at FIG. 3). Accordingly, the second axial member comprising the cam follower 14 maintains the inlet 22 closed when overpressure in the fluid chamber 20 is created or present. The second axial member comprising the cam follower 14 is configured to close the outlet 24 when the second axial member comprising the cam follower 14 rotates to a position corresponding to a minimum fluid chamber 20 volume (FIG. 3). The second axial member comprising the cam follower 14 is configured to maintain the outlet 24 closed when the second axial member comprising the cam follower 14 is rotating relative to the first axial member comprising the cam track 12 such that the fluid chamber 20 volume is increasing (e.g. between FIGS. 3 and 5). Accordingly, the second axial member comprising the cam follower 14 maintains the outlet 24 closed when underpressure in the fluid chamber 20 is created or present. The second axial member comprising the cam follower 14 is configured to open the outlet 24 when the second axial member comprising the cam follower 14 is rotated to a position corresponding to a maximum fluid chamber 20 volume (FIG. 5). The second axial member comprising the cam follower 14 is configured to maintain the outlet 24 open when the second axial member comprising the cam follower 14 is rotating relative to the first axial member comprising the cam track 12 such that the fluid chamber 20 volume is decreasing (from FIG. 5 to FIG. 6 and from FIG. 6 to a new rotation at FIG. 3). Accordingly, the second axial member comprising the cam follower 14 maintains the outlet 24 open when overpressure in the fluid chamber 20 is created or present. Accordingly, fluid is expelled through the outlet 24.

[0389] Reference is now made to FIGS. 7 through 12, which show a fluid transfer device, generally designated 110, in accordance with a second embodiment of the present invention. The fluid transfer device 110 is generally similar to that shown in FIG. 1, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 110 has a cam track 112 and cam follower 114 arrangement.

[0390] The first cam track wave 130 comprises a first neutral portion 134 of the waveform and a second neutral portion 136 of the waveform.

[0391] The first cam follower wave 132 comprises a first neutral portion 140 of the waveform and a second neutral portion 138 of the waveform.

[0392] The neutral portions 134, 136, 138, 140 are configured to maintain a relative axial position of the cam track 112 and cam follower 114 during relative rotation therebetween. Contact between the first neutral portions 134, 140 corresponds to a closing period of the inlet 122 (as shown in FIG. 11). Contact between the first neutral portion 134 of the cam track 112 and the second neutral portion 138 of the cam follower 114; and between the second neutral portion 136 of the cam track 112 and the first neutral portion 140 of the cam follower 114 corresponds to a closing period of the outlet 124 (as shown in FIG. 9). The periods provide for a transition between opening and closing the inlet 122 and the outlet 124; and for drawing fluid into and expelling fluid out of the chamber 120. Accordingly, no overlap in opening of the inlet 122 and the outlet 124 occurs (e.g. there is no simultaneous fluid communication with the chamber 120 via the inlet 122 and the outlet 124). Accordingly, any associated fluid pressure losses are reduced or eliminated.

[0393] Reference is now made to FIGS. 13 through 31, which show a fluid transfer device, generally designated 210, in accordance with a third embodiment of the present invention. The fluid transfer device 210 is generally similar to that shown in FIG. 7, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 210 has a cam track 212 and cam follower 214 arrangement. The device 210 further comprises a second cam track 251 with a second cam track wall means 252 and the cam follower 214 comprises a second cam follower wall means 254, and the second cam track wall means 252 and second cam follower wall means 254 face one another. The second cam track 251 is provided on a second stator 215.

[0394] The first and second cam track wall means 216, 252 are disposed so as to face one another.

[0395] The first and second cam follower wall means 218, 254 are disposed so as to oppose one another, e.g. back to back. In such disposition the cam follower 214 is disposed between the first and second cam track wall means 216, 252.

[0396] The second cam track wall means 252 comprises or provides a second cam track wave or waveform 256.

[0397] The second cam follower wall means 254 comprises or provides a second cam follower wave or waveform 258. The second cam follower wall means 254 is substantially in phase with the first cam follower wall means 218. Accordingly, the second cam follower waveform 258 is similar to the first cam follower waveform 238, separated by a thickness of the cam follower 214. In alternative embodiments, it will readily be appreciated that the second cam follower wall means may be out of phase with the first cam follower wall means (e.g. the second cam follower wall means and the second cam track wall means may be out of phasefor example, the second cam follower wall means may be an inversion of the first cam follower wall means).

[0398] The device 210 comprises a plurality of fluid chambers 220, 260, 262, 264. The plurality of chambers 220, 260, 262, 264 comprises a first pair of radially opposed chambers 220, 260; and a second pair of radially opposed chambers 262, 264. The plurality of fluid chambers 220, 260, 262, 264 are separated by portions of the cam follower 214. The pairs of fluid chambers 220, 260, 262, 264 are symmetrically arranged. The first pair of fluid chambers 220, 260 is arranged to be axially opposed to the second pair of fluid chambers 262, 264. The pairs of fluid chambers 220, 260, 262, 264 are arranged to provide a balanced relative movement between the cam follower 214 and the cam tracks 212, 251. The first pair of chambers 220, 260 comprises a pair of common inlets 222, 266 and a pair of exclusive respective outlets 224, 268. The second pair of chambers 262, 264 comprises a pair of common second inlets 270, 272 and a pair of exclusive respective outlets 274, 276. The chambers 220, 260, 262, 264 rotate relative to the inlets 222, 266, 270, 272 such that the pairs of inlets 222, 266, 270, 272 are in sequential fluid communication with the respective pairs of chambers 220, 260, 262, 264. The outlets 224, 268, 274, 276 rotate with the respective chambers 220, 260, 262, 264. The device 210 is configured such that the inlets 222, 266, of the first pair of fluid chambers 220, 260 is open whilst the inlets 270, 272 of the second pair of fluid chambers 262, 264 are closed (and vice versa) as can be seen in FIGS. 19 to 25. The device 210 is configured such that the outlets 224, 268 of the first pair of fluid chambers 220, 260 are open whilst the outlets 274, 276 of the second pair of fluid chambers 262, 264 are closed (and vice versa) as can be seen in FIGS. 27 to 31.

[0399] The device 210 is configured such that rotation of the second axial member comprising the cam follower 14 with the inner member 246 urges the cam follower 214 in a first axial direction corresponding to a first rotational position (e.g. upwards between FIGS. 14, 15 and 16). Accordingly the first pair of fluid chambers 220, 260 are in expansion during rotation at the first rotational position; and the second pair of fluid chambers 262, 264 are in compression, balanced with the first pair of fluid chambers 220, 260. Further rotation of the second axial member comprising the cam follower 14 with the inner member 246 urges the cam follower 214 in a second axial direction corresponding to another rotational position (e.g. downwards between the third rotational position of FIG. 16, to the rotational positions of FIGS. 17 and 18). Accordingly the first pair of fluid chambers 220, 260 are in compression during rotation at the further rotational position; and the second pair of fluid chambers 262, 264 are in expansion, balanced with the first pair of fluid chambers 220, 260.

[0400] The axially opposed first and second pairs of fluid chambers 220, 260, 262, 264 and the period of the waves (i.e. two complete waves per revolution) provides for a total of eight compressions and eight expansions per revolution (two for each of the four chambers 220, 260, 262, 264). Accordingly, the device 210 can provide for a smooth fluid transfer throughout a revolution. The inlets 222, 266, 270, 272 comprise a direction-dependent form, which is an offset slot form in the embodiment shown.

[0401] Reference is now made to FIGS. 32 to 46, which show a fluid transfer device 310, in accordance with a fourth embodiment of the present invention. The fluid transfer device 310 is generally similar to that shown in FIG. 13, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 310 has a cam track 312 and cam follower 314 arrangement.

[0402] The device 310 has a cam track 312 in the form of a circumferential groove 378 in the cam follower 314; which receives corresponding pins or rollers 380 from the outer member 342. Accordingly, the axial movement of the cam follower 314 corresponding to rotational position is defined by the path of the cam track 312, as shown in FIG. 34. Accordingly, the first and second stators 313, 315 are not required to bear all of the forces associated with the cam follower's 314 relative axial and rotational movement. In the embodiment shown, the device 310 comprises a pair of axially opposed fluid chambers 320, 362. The fluid chambers 320, 362 are singular annular chambers 320, 362. Accordingly no sealing contact is required between the walls of the rotor 315 and the stators 313, 315.

[0403] In alternative embodiments, it will be appreciated that a sealing member may be provided between the cam follower 314 and the first stator 313; and between the cam follower 314 and the second stator 315 (e.g. a resilient seal). Accordingly, a plurality (e.g. pair) of radially arranged or opposed chambers may be provided.

[0404] The cam follower 314 is keyed to the inner member 346, as shown in FIG. 32, such that the cam follower 314 is axially movable relative to the inner member 246 (rather than only being axially movable with the inner member as in the second embodiment). Accordingly, the inner member 346 needs only to rotate; and no axial movement of the inner member 346 (or outer member 342) is required for operation of the device 310. The stators 313, 315 are fixed axially and rotationally to the outer member 342.

[0405] The device 310 functions similarly to that of FIGS. 13 to 31, with fluid being sequentially drawn into the expanding fluid chambers 320, 362 through the respective fluid inlets; and expelled from the subsequently compressing chambers through the fluid outlets (not shown); as is shown sequentially in FIGS. 40 to 46 (similar to FIGS. 19 to 25). However, the wave form of the groove 378 has a greater amplitude relative to the opposing faces of the stators 313, 315 and the rotor 314. Accordingly, the rotor 314 has an increased axial movement compared to the device 210 of FIG. 13. The increased axial movement allows the annular chambers 320, 362 to be sequentially axially opened and closed as shown in FIGS. 39 to 46.

[0406] Reference is now made to FIGS. 47 to 53, which show a fluid transfer device 410, in accordance with a fifth embodiment of the present invention. The fluid transfer device 410 is generally similar to that shown in FIG. 32, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 410 has a cam track 412 and cam follower 414 arrangement.

[0407] The device 410 comprises a plurality of fluid chambers 420, 460, 462, 464. The plurality of chambers 420, 460, 462, 464 comprises a first pair of radially opposed chambers 420, 460; and a second pair of radially opposed chambers 462, 464. The plurality of fluid chambers 420, 460, 462, 464 are separated by portions of the cam follower 414. The pairs of fluid chambers 420, 460, 462, 464 are symmetrically arranged. The first pair of fluid chambers 420, 460 is arranged to be axially opposed to the second pair of fluid chambers 462, 464. The pairs of fluid chambers 420, 460, 462, 464 are arranged to provide a balanced relative movement between the cam follower 414 and the cam tracks 412, 451. The first pair of chambers 420, 460 comprises a pair of common inlets 422, 466 and a pair of exclusive respective outlets 424, 468. The second pair of chambers 462, 464 comprises a pair of common second inlets (not shown) and a pair of exclusive respective outlets (not shown). Although not shown, it will be appreciated that the second pair of fluid chambers 462, 464 communicates with a similar, symmetrical and axially aligned arrangement of inlets and outlets. The chambers 420, 460, 462, 464 rotate relative to the inlets 422, 466 such that the pairs of inlets 422, 466 are in sequential fluid communication with the respective pairs of chambers 420, 460, 462, 464. The outlets 424, 468, rotate with the respective chambers 420, 460, 462, 464. The device 410 is configured such that the inlets 422, 466, of the first pair of fluid chambers 420, 460 is open whilst the inlets of the second pair of fluid chambers 462, 464 are closed (and vice versa) as can be seen in FIGS. 47 to 53. The device 410 is configured such that the outlets 424, 468 of the first pair of fluid chambers 420, 460 are open whilst the outlets of the second pair of fluid chambers 462, 464 are closed (and vice versa) as can also be seen in FIGS. 47 to 53.

[0408] The stators 413, 415 are axially urged against the cam follower 414. The device 410 is configured such that rotation of the cam follower 414 with the inner member 446 urges the second stator 415 in a first axial direction corresponding to a first rotational position (e.g. to the left between FIGS. 47 and 53). Accordingly the second cam track wall means 452 and the second cam follower wall means 454 are maintained in sealing contact. Simultaneously the first stator 413 is urged in the same axial direction, maintaining contact with between the first cam track wall means 416 and the first cam follower wall means 418.

[0409] The first pair of fluid chambers 420, 460 are in compression during rotation at the first rotational position (from FIGS. 47 to 53); and the second pair of fluid chambers 462, 464 are in expansion, balanced with the first pair of fluid chambers 420, 460. Further rotation of the cam follower 414 with the inner member 446 moves the stators 413, 415 in a second axial direction corresponding to another rotational position (e.g. to the right during further rotation from the position of FIG. 47not shown). Accordingly the first pair of fluid chambers 420, 460 are in compression during further rotation (not shown); and the second pair of fluid chambers 462, 464 are in expansion, balanced with the first pair of fluid chambers 420, 460. It will readily be appreciated, that such simultaneous expansion and compression of the respective pairs of fluid chambers 420, 460, 462, 464 is repeated sequentially and successively as the cam follower 414 rotates further.

[0410] The axially opposed first and second pairs of fluid chambers 220, 260, 262, 264 and the period of the waves (i.e. two complete waves per revolution) provides for a total of eight compressions and eight expansions per revolution (two for each of the four chambers 220, 260, 262, 264). Accordingly, the device 210 can provide for a smooth fluid transfer throughout a revolution. The inlets 222, 266, 270, 272 comprise a direction-dependent form, which is an offset slot form in the embodiment shown.

[0411] The device 410 functions generally similarly to that of FIGS. 13 to 31, with the stators 413, 415 being keyed to the outer member 442 and axially movable relative thereto. However, rather than the rotor 417 opening and closing the inlets 422, 460, the common inlets 422, 460 of the first pair of fluid chambers 420, 460 are sequentially opened and closed by the relative axial movement of the first stator 413. The stator 413 also sequentially opens closes the respective outlets 424, 468 (as the outlets 424, 468 sequentially rotate past the axially moving peaks of the waveform 430 of the first cam track 412).

[0412] Reference is now made to FIGS. 54 to 58, which show a fluid transfer device 510, in accordance with a sixth embodiment of the present invention. The fluid transfer device 510 is generally similar to that shown in FIG. 47, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 510 has a cam track 512 and cam follower 514 arrangement.

[0413] However, the device 510 shown in FIGS. 54 to 58 comprises an engine. The device comprises a cam follower 514 in the form of a piston body 581 on an inner member 546 in the form of a hollow shaft 582. Both ends of the piston 581 are faceted to produce respective rotor faces 583. The cam follower 514 comprises the cam track 512; in the form of a continuous channel or groove 578 cut into the mid part 584 of the piston 581 with a first cam track waveform 530.

[0414] FIG. 55 shows the piston body 581 contained within an outer cylinder casing 586 through the walls of which are fixed at diametrically opposed points two fixed bearing pins or rotary bearings 585.

[0415] FIGS. 56 to 58 show three sections through the device of FIG. 54. FIG. 56 shows the piston body 581 within the cylinder casing 586 at one extreme of the travel distance on the shaft 542 permitted it by the combination of the fixed pins or bearings 585 moving within the wave channel 578.

[0416] FIG. 57 shows the piston body 581 after a rotary motion through 90 degrees of travel. The piston body 581 has now reached the other extreme of its permitted travel distance due to the combined action of the fixed pins or bearings 585 moving within the wave channel 578.

[0417] FIG. 58 shows the position of the piston body 581 after a further rotary motion of 90 degrees. The piston body 581 has now returned to the original position in which it was shown in FIG. 56. Piston scraper rings 590 have been shown in all of FIGS. 56 to 58.

[0418] It can be seen that, with the number of fixed pins or bearings 585 shown combined with the given wave channel 578, each full 360 degrees of rotary motion of the piston body 514 will cause it to move up and down the cylinder casing twice 546 in each direction.

[0419] In use, the closed ends of the cylinder casing 542 and the faces 583 of the moving piston body 581 provides resistant surfaces to contain the explosive force of detonated fuel/air mixtures introduced into the chambers 520, 562 as required and the exhaust gasses removed through suitable apertures revealed by the motion of the piston body 681 in the cylinder casing 642.

[0420] Reference is now made to FIGS. 59 to 60, which show a fluid transfer device 610, in accordance with a seventh embodiment of the present invention. The fluid transfer device 610 is generally similar to that shown in FIG. 54, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 610 has a cam track 612 and cam follower 614 arrangement.

[0421] The arrangement of piston body 681 and cylinder casing 642 is similar to that of FIG. 54, but the casing 642 head is profiled to correspond to the rotor faces 683. The rotor faces 683 shown each have two angular facets to influence rotational direction of the piston body 681.

[0422] Reference is now made to FIGS. 61 to 62, which show a fluid transfer device 710, in accordance with an eighth embodiment of the present invention. The fluid transfer device 710 is generally similar to that shown in FIG. 59, with like features comprising like reference numerals, incremented by 100. Accordingly, the device 710 has a cam track 712 and cam follower 714 arrangement.

[0423] FIG. 61 shows the piston body 781 on a hollow shaft 746. Both ends of the piston 681 are faceted to produce rotor faces 783. Cut into the mid part of the piston is a continuous wave channel 778. The outer surface of the piston body 781 has been extended to form a hollow skirt 797 into which have been cut shaped openings 792 to admit the passage of gasses.

[0424] FIG. 62 shows the piston body 781 contained within an outer cylinder casing 742 through the walls of which are fixed at diametrically opposed points two fixed pins or rotary bearings 785. The gas openings 792 in the piston skirts 797 are so arranged as to pass over the gas inlet/exhaust apertures 722, 724 in the cylinder casing walls 742.

[0425] FIG. 63 shows an apparatus 810 according to a ninth embodiment of the invention, comprising two devices 710a,b of FIG. 61 with like reference numerals 712a,b, 714a,b, 792a,b referring to like components. The two opposed pistons 781 are contained in the common cylinder casing 742 and mounted on the same hollow shaft 746. The fixed pins or rotary bearings 785 protruding through the cylinder casing 742 engage the wave channels 778 running round the piston bodies 781. Whilst the piston bodies 781 are free to move on the hollow shaft 746 in a lateral manner, rotary motion of the piston bodies 781 must cause rotation of the shaft 742 by means of keys 796a,b fixed to the shaft 742 and engaging key movement restraints 798a,b within the piston bodies 781. The shaft 742 cannot move laterally as it is restrained from doing so by bearings and seals 799 set in the cylinder casing end walls.

[0426] Valve apertures 791 are arranged in the chambers 720a,b, 762a,b walls to admit passage of fuel/air and exhaust gasses as required. These are serviced by suitable ducts 789. Surrounding the cylinder casing 742 is a thin walled metal sheet duct 787 so providing a cooling channel 793 for the passage of air assisted by cooling impellers 779 which can be situated at both ends of the cooling channel 793.

[0427] The shaft 746 can be arranged to drive any and all of such ancillary equipment at either or both ends of the cylinder casing 742.

[0428] The piston bodies 781 are equipped with scraper rings 790 to remove oil first introduced to the cylinder by oil delivery apertures 791 in the wave channels 778 cut in the piston bodies 781.

[0429] FIG. 64 shows the apparatus 810 of FIG. 63 with the piston bodies 781 having travelled through 90 degrees of rotation, and the respective chambers 720a and 762b having been compressed under pressure of combustion expansion in the opposing chambers 762a and 720b.

[0430] FIG. 65 shows a cross section of the apparatus 810 of FIG. 63.

[0431] FIG. 66 shows a cross section of the apparatus 810 of FIG. 64.

[0432] Reference is now made to FIGS. 67 to 86, which show a portion of an apparatus 905 according to a tenth embodiment of the present invention. The apparatus 905 is generally similar to that shown in FIG. 63, with like features comprising like reference numerals, incremented by 100. Accordingly, the apparatus 905 comprises a plurality of fluid transfer devices 910. In the embodiment shown, a ring-shaped annular chamber 920 is defined between the first and second axial members 912a, 914a of each device 910. The fluid chamber 920 is disposed axially distal of the cam tracks 912b. The first and second axial member/s 912a, 914a comprise cam followers 914b that are disposed between the fluid chamber 920 and the cam tracks 912b.

[0433] The inner member 946 of the apparatus 905 is common to both the fluid transfer devices 910 and comprises a first inner member 946. In the embodiment shown, the first inner member 946 comprises a hollow drive shaft for rotatably driving the first and second axial members 912a, 914a. The apparatus 905 comprises a further or second inner member 947. The further or second inner member 947 comprises a shaft, which is also hollow in the embodiment shown. The further or second inner member 947 comprises a fluid conduit. The further or second inner member 947 comprises a second inner member throughbore 950. The further or second inner member 947 is mounted or provided in or within the first inner member 946. The further or second inner member 947 is mounted coaxially and/or concentrically with the first inner member 946. The first inner member 946 is relatively rotatable with respect to the further or second inner member 947. The first and second inner members 946, 947 are mounted in a tight fit. The first and second inner members are mounted so as to substantially prevent a fluid passage between the first and second inner members 946, 947. The first and second inner members 946, 947 are mounted so as to substantially eliminate any fluid passage between an outer surface of the second inner member 947 and the inner surface of the first inner member 946. The first inner member 946 defines an outer sleeve. The second inner member 947 defines an inner sleeve. In the embodiment shown, the first and second inner members 946, 947 are relatively rotatable to selectively open and close the fluid outlets 924. In other embodiments (not shown), the first and second inner members 946, 947 are relatively rotatable to selectively open and close the fluid inlets (e.g. the pump/motor/engine may work in reverse and the fluid outlet 924 may function as a fluid inlet). The first and second/further inner members 946, 947 comprise apertures or openings 923, 925. The apertures or openings 923, 925 of the first and second/further inner members 946, 947 are configured to align to open the fluid outlets 924. The apertures or openings 923, 925 of the first and second/further inner members are configured to periodically align, such as during predetermined phases or positions of a relative rotation between the first and second inner members 946, 947. In the embodiment shown, the first inner member 946 comprises fewer openings or apertures 923 than the second inner member 947. In the embodiment shown, the inner member 947 comprises a single opening or aperture 923 and the second/further inner member 947 comprises a plurality of apertures/openings 925. In alternative embodiments, the first inner member 947 comprises a similar number and/or arrangement of opening/s or aperture/s 923 as the second inner member 947. In alternative embodiments, the first inner member 946 comprises a plurality of apertures or openings 923 and optionally more openings or apertures 923 than the second inner member 947.

[0434] FIGS. 68 and 69 show an assembled portion of the apparatus 905 of FIG. 67 with the chamber 920 in a minimum volume configuration. The respective inlets 922 are closed by the respective second axial members or cam followers 914. Similarly, the respective outlets 924 are closed as can be seen in FIG. 69.

[0435] FIGS. 70 and 71 show the portion of the apparatus 905 of FIG. 67 with the volume of chamber 920 increased from that shown in FIG. 68, in accordance with a relative axial and rotational movement between the respective first and second axial members 912a,b, 914a,b from the positions shown in FIGS. 68 and 69. The respective inlets 922 are still maintained closed by the respective second axial members or cam followers 914a,b. Similarly, the respective outlets 924 are closed as can be seen in FIG. 69. As the volume of the chamber 920 increases with both inlets and outlet 922, 924 closed, an underpressure is created in the chamber 920.

[0436] FIGS. 72 and 73 show portion of the apparatus 905 of FIG. 67 with the volume of chamber 920 increased from that shown in FIG. 70, in accordance with a relative axial and rotational movement between the respective first and second axial members 912, 914 from the positions shown in FIGS. 70 and 71. The respective inlets 922 have been opened by the respective second axial members or cam followers 914. The outlet 924 is still closed as can be seen in FIG. 73. The volume of the chamber 920 is at its maximum. With the inlets 922 open, the underpressure created in the chamber 920 by the movement of the second axial members or cam followers 914 from the positions of FIGS. 68 and 69 to the positions of FIGS. 72 and 73, causes fluid to be rapidly drawn into the chamber 920 through the inlets 922.

[0437] FIGS. 74 and 75 show portion of the apparatus 905 of FIG. 67 with the volume of chamber 920 decreased from that shown in FIG. 70, in accordance with a relative axial and rotational movement between the respective first and second axial members 912, 914 from the positions shown in FIGS. 72 and 73. The respective inlets 922 have been closed by the respective second axial members or cam followers 914. The outlet 924 has been opened due to the alignment of the respective openings or apertures 923, 925 in the first and second inner members 946, 947, as can be seen in FIG. 75. With the inlets 922 closed and the outlet 924 open, the overpressure created in the chamber 920 by the movement of the second axial members or cam followers 914 from the positions of FIGS. 72 and 73 to the positions of FIGS. 74 and 75, causes fluid to be expelled from the chamber 920 through the outlet 924.

[0438] FIGS. 76 and 77 show the portion of the apparatus 905 of FIG. 67 with the volume of the chamber 920 decreased from that shown in FIG. 74, in accordance with a relative axial and rotational movement between the respective first and second axial members 912, 914 from the positions shown in FIGS. 74 and 75. The respective inlets 922 are still closed by the respective second axial members or cam followers 914. The outlet 924 has just been closed due to the misalignment of the respective openings or apertures 923, 925 in the first and second inner members 946, 947, as can be seen in FIG. 77. The fluid chamber 920 has been returned to its minimum volume configuration, similar to that of FIG. 68, with substantially all of the intaken fluid expelled from the chamber 920 through the outlet 924. The apparatus 905 can be endlessly cycled through the positions of FIGS. 68 to 77.

[0439] FIG. 78 shows a partial cross-sectional detail of the portion of the apparatus 905 of FIG. 67 in which an optional recess, cavity or sump 929 in the first and second axial members 912a, 914a has been provided to accommodate debris or residue that is not initially expelled through the outlet 924 and may otherwise prevent or hinder the movement of the first and second axial members 912a, 914a. The first and second axial members 912a, 914a are configured to accommodate the particles or solids. The device 910 is configured to provide a clearance between the first and second axial members 912a, 914a, such as a clearance between first and second axial members 912a, 914a throughout an entire cycle of relative movement between the first and second axial members 912a, 914a. The device 910 is configured to prevent particles or solids being trapped or compressed between first and second axial members 912a, 914a. The particle recess, cavity or sump 929 is for receiving particles, such as when the chamber 920 is in a minimum volume state or substantially closed. The device 910 is configured to permit a rapid opening and/or closing of the inlet/s 922 and/or outlet/s 924.

[0440] FIGS. 79 to 81 show a greater portion of the apparatus 905 of FIG. 67, with FIG. 81 showing the relative positions of the first and second inner members 946, 947 for three chambers 920 x, y and z as the second axial members or cam followers 914 transition between the positions shown in FIGS. 79 and 80. It will be appreciated that in the embodiment shown, that alternate chambers 920 are compressed or expanded by the rotation of the common first inner member 946 (e.g. chambers 920x and 920z intake and expel fluid simultaneously, which is directly out of phase with chamber 920y). Accordingly, fluid transfer is smoothed. It will be appreciated that in alternative embodiments all of the chambers 920 could be in phase, and/or there could be an increased number of phases and/or the phases could be partial (e.g. 30, 60, 90 degrees out of phase, or the like).

[0441] FIG. 82 shows an eleventh embodiment of the present invention of an apparatus 1005 with devices 1005. The first and second axial members 1012a, 1014a are generally similar to that shown in FIGS. 67 to 81. The first axial members 1014a with cam followers 1014b comprise axial projections 1031 to selectively open and/or close the inlets. The axial projections 1031 comprise an outer annular axial projection. The projections 1031 comprise tongue. In other embodiments, the projections 1031 comprise a wing or lobe or tab or boss or the like. The projections 1031 are configured to restrict fluid passage into the chamber 1020, such as when the projections 1031 are aligned with the respective inlets. The projections 1031 comprise an aperture 1033, which is a port in the embodiment shown. The projection's 1031 aperture 1033 defines a fluid passage into the fluid chamber 1020 from the inlet when aligned with the inlet.

[0442] The provision of an axial projection may enable an increased inlet/s' and/or outlet/s' size and/or dimension and/or shape. The provision of the axial projection 1031 restricts a period of opening of the inlet (not shown) such that an inlet size, such as an inlet diameter, may be increased (e.g. compared to the second axial member or cam followers 914 of FIG. 67). Accordingly, the inlet may be a larger diameter circle than otherwise would be possible without the projection 1031 (without affecting device efficiency, such as by opening the inlet during a portion of a chamber exhaust stroke). An increased inlet may allow the passage of particles, such as carried by the fluid, without blocking or significantly damaging the device 1010. There is provided an axial recess, cavity or pocket 1035 for receiving the projection 1031.

[0443] FIG. 83 shows a portion of a path of the aperture 1033 in the projection 1031 relative to an inlet 1022. The aperture 1033 is shown in broken line, with the inlet 1022 shown in solid line. In the embodiment shown, the aperture 1033 is aligned, or partially aligned with the inlet 1022, so as to overlap, only in an outermost axial configuration (the lowermost three positions shown in FIG. 83). Aside from these three positions, when the aperture 1033 and inlet 1022 are not aligned or partially aligned, the projection 1031 or the remainder of the second axial member or cam follower 1014 blocks the inlet 1022 such that it is closed.

[0444] FIGS. 84 to 88 show the relative positions of the inlets 1022, outlets 1024, openings or apertures 1023, 1025 in the first and second inner members 1046, 1047, and the projections 1031 with apertures 1033. It will be appreciated that the position shown in FIGS. 84 to 88 correspond generally to the positions shown in FIGS. 69, 73, 77, 73 and 69 respectively.

[0445] Reference is now made to FIGS. 89 to 104, which show a portion of an apparatus 1105 according to a twelfth embodiment of the present invention. The apparatus 1105 is generally similar to that shown in FIG. 82, with like features comprising like reference numerals, incremented by 100. The apparatus 1105 comprises a plurality of fluid transfer devices 1110. The fluid transfer device 1110 shown comprises an inner member 1146 with a central axis 1028 and comprising an outer surface 1148. The fluid transfer device 1105 has an outer member 1142 coaxially arranged with the inner member 1146 and comprising an inner surface 1144 radially spaced from the outer surface 1148 of the inner member 1146 to define a space between the inner and outer members 1146, 1142. The device 1110 has a first axial member 1112a and a second axial member 1114a. At least one variable fluid chamber 1120 is defined in the space. There is a fluid inlet 1122 to the at least one fluid chamber 1120; and a fluid outlet 1124 from the at least one fluid chamber 1120.

[0446] At least one of the first and/or second axial member/s 1112a, 1114a is rotatable about the central axis 1028 to vary a volume of the at least one fluid chamber 1120. In the embodiment shown, both of the first and/or second axial member/s 1112a, 1114a are rotatable about the central axis 1028 to vary a volume of the at least one fluid chamber 1120. The volume of the at least one fluid chamber 1120 corresponds to a rotational position of the first and second axial members 1112a, 1114a.

[0447] The plurality of devices 1110 comprises a plurality of similar devices 1110. In the embodiment shown, the apparatus 1105 comprises a plurality of pump devices 1110.

[0448] It will be appreciated that in alternative embodiments, the apparatus 1105 additionally or alternatively comprises a plurality of dissimilar devices 1110, such as at least one motor device 1110 and at least one pump device 1110.

[0449] The plurality of devices 1110 are arranged in series. The plurality of devices 1110 is coaxially arranged. The plurality of devices 1110 are axially arranged or distributed.

[0450] The apparatus 1105 comprise a symmetrical arrangement of devices 1110. The symmetrical arrangement is rotationally symmetrical. The symmetrical arrangement is an inversion (e.g. a second device 1110 mirrors a first device 1110). The plurality of devices 1110 are arranged to provide a smooth output. The smooth output is a fluid output.

[0451] The plurality of devices 1110 is axially balanced. The plurality of devices 1110 is rotationally balanced. The plurality of devices 1110 is configured to be in phase. The plurality of devices 1110 is configured to be out of phase. The plurality of devices 1110 is configured to be in antiphase. In the embodiment shown adjacent devices 1110 are configured to be in antiphase and alternate devices 1110 are configured to be in phase.

[0452] The plurality of devices 1110 is connected. For example, the plurality of devices 1110 is connected such that a single input (e.g. a rotation of the inner member 1146) drives the plurality of devices 1110. In alternative embodiments, the plurality of devices 1110 is connected such that the devices 1110 drive a single output (e.g. a rotation of an inner member or a generation of a fluid pressure).

[0453] It will be appreciated that in the embodiment shown, that alternate chambers 1120 are compressed or expanded by the rotation of the common first inner member 1146 (e.g. chambers 1120x and 1120z intake and expel fluid simultaneously, which is directly out of phase with chamber 1120y). Accordingly, fluid transfer is smoothed. It will be appreciated that in alternative embodiments all of the chambers 1120 could be in phase, and/or there could be an increased number of phases and/or the phases could be partial (e.g. 30, 60, 90 degrees out of phase, or the like).

[0454] The space comprises an annulus. The space comprises a substantially uniform inner and/or outer diameter. The space is substantially radially symmetrical. The space is substantially radially homogenous. The fluid chamber 11120 is substantially radially symmetrical. The fluid chamber 1120 is substantially radially homogenous. The fluid chamber 1120 is of substantially uniform height across at least a portion of its diameter and/or around at least a portion of its circumference. The fluid chamber 1120 is of substantially uniform height across at least a portion of its diameter and around at least a portion of its circumference for each position of the first and second axial members 1112a, 1114a.

[0455] The first and second axial members 1112a, 1114a are disposed in the space.

[0456] The at least one fluid chamber 1120 is disposed between the first and second axial members 1112a, 1114a.

[0457] The at least one of the first and/or second axial member/s 1112a, 1114a is rotatable about the central axis 1028 to substantially close the at least one fluid chamber 1120. The at least one of the first and/or second axial member/s 1112a, 1114a is configured to stroke or axially displace within the space to substantially close the at least one fluid chamber 1120.

[0458] The at least one fluid chamber 1120 is substantially defined by the first axial member 1112a, the second axial member 1114a, the inner member 1146 and the outer member 1142. The at least one fluid chamber 1120 is disposed adjacent the inner member 1146 and the outer member 1142 and the first and second axial members 1112a, 1114a.

[0459] In other embodiments, the at least one fluid chamber 1120 is disposed axially distal of at least one of the first and second axial members 1112a, 1114a. For example, the second axial member 1114a is disposed between the fluid chamber 1120 and the first axial member 1112a.

[0460] The device 1110 comprises a throughbore 1150. The device 1110 comprises an axial throughbore 1150. The throughbore may axially pass or pass through the fluid chamber 1120. The throughbore 1150 is at least selectively fluidly isolated from the fluid chamber 1120. The device 1110 is configured to permit an axial passage of apparatus therethrough. For example, the throughbore 1150 is configured to permit the axial passage of a wireline, slickline, coiled tubing, drop-ball, or the like. The throughbore 1150 comprises an axial fluid conduit.

[0461] The device 1110 comprises a pump. A volume of the at least one fluid chamber 1120 varies in response to a mechanical input. For example, the at least one fluid chamber 1120 volume varies in response to a rotation of the first and second axial members 1112a, 1114a.

[0462] In other embodiments, the device 1110 comprises a motor. A volume of the at least one fluid chamber 1120 varies in response to a fluid pressure. For example, the at least one fluid chamber 1120 volume varies in response to a fluid pressure differential, such as differential fluid pressure across the inlet 1122 and/or the outlet 1124.

[0463] In other embodiments, the device 1110 comprises an engine. For example, at least a portion of the at least one fluid chamber 1120 comprises a combustion chamber 1120. The at least one fluid chamber 1120 volume varies in response to a change in internal at least one fluid chamber 1120 pressure, such as caused by a combustion therein. The outlet/s comprises an exhaust outlet/s.

[0464] A volume of the at least one fluid chamber 1120 corresponds to an axial position of the first and/or second axial member/s 1112a, 1114a. The axial position comprises an axial separation. The device 1110 comprises a rotor. The second axial member 1114a comprises a rotor. The second axial member 1114a comprises a piston head. The device 1110 comprises a stator. The first axial member 1112a comprises a stator. The first axial member 1112a comprises a cylinder.

[0465] An axial position/s of the first and/or second axial member/s 1112a, 1114a corresponds to a rotational position of the first and/or second axial member/s 1112a, 1114a respectively.

[0466] The device 1110 is configured to transfer a bore fluid. The device 1110 is configured to transfer a bore fluid within a bore of the device 1110, such as axially transfer an internal bore fluid and/or axially transfer an external bore fluid. The device 1110 is configured to transfer a bore fluid between an internal device 1110 bore and an external device bore. The device 1110 is configured to transfer a bore fluid substantially radially. The device 1110 comprises a downhole device. The bore fluid comprises a formation fluid and/or an injection fluid and/or a drilling fluid. The device 1110 comprises a downhole pump.

[0467] In alternative embodiments or applications, the fluid comprises water. The device 1110 comprises a dewatering device. The device 1110 is configured to transport light or non-viscous fluids. The inner and/or outer and/or first and/or second axial member/s 1112a, 1114a comprises materials suitable for use downhole, such as to withstand a high pressure high temperature condition. The inner and/or outer and/or first and/or second axial member/s 1112a, 1114a comprise a metal, such as steel, titanium, alloys or the like and/or a plastic, such as PEEK, and/or a ceramic.

[0468] In alternative embodiments, the device 1110 comprises a medical device. The device 1110 comprises an implantable device. The device 1110 comprises a prosthesis. The device 1110 comprises an endoprosthesis. The fluid comprises a bodily fluid. The fluid comprises blood. The inner and/or outer and/or first and/or second axial member/s 1146, 1142, 1112a, 1114a comprise materials suitable for implantation, such as to be accepted and/or to inhibit and/or discourage integration into an implantation site. The inner and/or outer 1142, 1146 and/or first and/or second axial member/s 1112a, 1114a comprises a metal, such as steel, titanium, alloys, nitinol, or the like and/or a plastic, such as PTFE or PE or PP, and/or a ceramic.

[0469] The device 1110 is configured to selectively open and/or close the inlet/s 1122 and/or outlet/s. The device 1110 is configured to selectively open and/or close the inlet 1122 according to a rotational position of the first and/or second axial member/s 1112a, 1114a. The device 1110 is configured to selectively maintain the inlet 1122 open according to a rotational position of the first and/or second axial member/s 1112a, 1114a. The device 1110 is configured to selectively close the inlet 1122 according to a rotational position of the first and/or second axial member/s 1112a, 1114a. The device 1110 is configured to selectively maintain the inlet 1122 closed according to a rotational position of the first and/or second axial member/s 1112a, 1114a.

[0470] The device 1110 is configured to open the inlet 1122 when the first and/or second axial member/s 1112a, 1114a rotates to a position corresponding to a minimum volume of the at least one fluid chamber 1120. The device 1110 is configured to maintain the inlet 1122 open for at least a portion of a rotation of the first and/or second axial member/s 1112a, 1114a wherein the at least one fluid chamber 1120 volume is increasing. Accordingly, the first and/or second axial member/s 1112a, 1114a opens and/or maintains the inlet 1122 open for at least a portion of a period when underpressure in the at least one fluid chamber 1120 is created or present. Accordingly, fluid is drawn into the at least one fluid chamber 1120 through the inlet 1122 (for example, when functioning as a pump and/or as an engine).

[0471] The device 1110 is configured to open the inlet 1122 for only a portion of a period when the volume of the fluid chamber 1120 is increasing. The device 1110 is configured to only open the inlet 1122 after the volume of the chamber 1120 has been at least partially increased. Accordingly, the inlet 1122 is opened when an underpressure in the chamber 1120 has already been created. Accordingly a pressure differential across the inlet 1122 is increased. Accordingly a flow rate into the chamber 1120 is increased.

[0472] The device 1110 is configured to selectively close the outlet/s 1124 according to a rotational position of the first and/or second axial member/s 1112a, 1114a. The device 1110 is configured to close the inlet 1122 when the first and/or second axial member/s 1112a, 1114a rotates to a position corresponding to a maximum at least one fluid chamber 1120 volume. The device 1110 is configured to maintain the inlet 1122 closed when the first and/or second axial member/s 1112a, 1114a is rotating such that the at least one fluid chamber 1120 volume is decreasing. Accordingly, the device 1110 maintains the inlet 1122 closed when overpressure in the at least one fluid chamber 1120 is created or present. The device 1110 is configured to close the outlet 1124 when the first and/or second axial member/s 1112a, 1114a rotates to a position corresponding to a minimum at least one fluid chamber 1120 volume. The device 1110 is configured to maintain the outlet 1124 closed when the first and/or second axial member/s 1112a, 1114a is rotating such that the at least one fluid chamber 1120 volume is increasing. Accordingly, the device 1110 maintains the outlet 1124 closed when underpressure in the at least one fluid chamber 1120 is created or present. The device 1110 is configured to open the outlet 1124 when the first and/or second axial member/s 1112a, 1114a rotates to a position corresponding to a maximum at least one fluid chamber 1120 volume. The device 1110 is configured to maintain the outlet 1124 open for at least a portion of a period when the first and/or second axial member/s 1112a, 1114a is rotating such that the at least one fluid chamber 1120 volume is decreasing. Accordingly, the first and/or second axial member/s 1112a, 1114a opens and/or maintains the outlet 1124 open for at least a portion of a period when overpressure in the at least one fluid chamber 1120 is created or present. Accordingly, fluid is expelled through the outlet 1124.

[0473] The device 1110 is configured to open and/or close the inlet/s 1122 and/or outlet/s 1124 in accordance with a fluid property. The device 1110 is configured to open and/or close the inlet/s 1122 and/or outlet/s 1124 in accordance with a predetermined and/or projected fluid property, such as one or more of: a fluid pressure and/or temperature and/or viscosity; and/or a pressure differential across the inlet/s 1122 and/or outlet/s 1124. The fluid property is of the fluid external to the device 1110, in the chamber 1120 and/or in the throughbore 1150.

[0474] The device 1110 is configured to open the inlet 1122 when the first and/or second axial member/s 1112a, 1114a is rotated to a position corresponding to a minimum at least one fluid chamber 1120 volume (e.g. when functioning as a motor).

[0475] The device 1110 is configured to maintain the inlet 1122 open for at least a portion of a period when the at least one fluid chamber 1120 volume is increasing under fluid pressure such that the first and/or second axial member/s 1112a, 1114a is rotating. Accordingly, the device 1110 maintains the inlet 1122 open for at least a portion of a period when overpressure in the at least one fluid chamber 1120 is created or present. Accordingly, fluid is pumped into the at least one fluid chamber 1120 through the inlet 1122 (for example, when functioning as a motor or engine). Accordingly a relative movement of the first and/or second axial member/s 1112a, 1114a is driven by a pumped fluid. The relative movement is axial and/or rotational. The device 1110 is configured to close the inlet 1122 when the first and/or second axial member/s 1112a, 1114a is rotated to a position corresponding to a maximum at least one fluid chamber 1120 volume. The first and/or second axial member/s 1112a, 1114a is configured to maintain the inlet 1122 closed when the at least one fluid chamber 1120 volume is decreasing such that the fluid is expelled or drawn out of the chamber 1120. Accordingly, the device 1110 maintains the inlet 1122 closed when overpressure in the at least one fluid chamber 1120 is present. The device 1110 is configured to close the outlet 1124 when the first and/or second axial member/s 1112a, 1114a rotates to a position corresponding to a minimum at least one fluid chamber 1120 volume. The device 1110 is configured to maintain the outlet 1124 closed for at least a portion of a period when the at least one fluid chamber 1120 volume is increasing such that the first and/or second axial member/s 1112a, 1114a is rotating. Accordingly, the device 1110 maintains the outlet 1124 closed for at least a portion of a period when overpressure in the at least one fluid chamber 1120 is created or present. The device 1110 is configured to open the outlet 1124 when the first and/or second axial member/s 1112a, 1114a rotates to a position corresponding to a maximum at least one fluid chamber 1120 volume. The device 1110 is configured to maintain the outlet 1124 open for at least a portion of a period when the at least one fluid chamber 1120 volume is decreasing such that the first and/or second axial member/s 1112a, 1114a is rotating. Accordingly, the device 1110 opens or maintains the outlet 1124 open to vent the chamber 1120 to create an underpressure to decrease the volume of the chamber 1120.

[0476] The first and/or second axial member/s 1112a, 1114a comprises an axial projection/s 1131 to selectively open and/or close the inlet/s 1122 and/or outlet/s 1124. The axial projection 1131 comprises a wing or a tongue in the embodiment shown. The projection 1131 is configured to restrict fluid passage into the chamber 1120, such as when the projection is aligned with the inlet/s 1122. The projection comprises an aperture 1133, such as a slot, an open slot, a recess, a port, an opening, a cutaway or the like. The projection's aperture 1133 defines a fluid passage into the fluid chamber 1120 from the inlet/s 1122 when aligned with the inlet/s 1122. The projection's aperture defines a fluid passage out of the fluid chamber 1120 through the outlet/s 1124 when aligned with the outlet/s 1124.

[0477] The provision of an axial projection 1131 enables an increased inlet/s 1122 1124 size and/or dimension and/or shape. For example, the provision of an axial projection 1131 restricts a period of opening of an inlet 1122 such that an increased inlet size, such as an inlet diameter, is provided. Accordingly, the inlet 1122 is a larger opening than otherwise would be possible without the projection (without affecting device 1110 efficiency, such as by opening the inlet 1122 during a chamber 1120 exhaust stroke). An increased inlet 1122 allows the passage of particles, such as carried by the fluid, without blocking or significantly damaging the device 1110.

[0478] There is provided an axial recess or pocket 1135 for receiving the projection 1131. The other of the first or second axial member/s 1112a, 1114a comprises the axial recess or pocket 1135 for receiving the projection 1131.

[0479] The first axial member 1112a comprises a first axial member wall means. The second axial member 1114a comprises a second axial wall means. The fluid chamber 1120 is defined between the first and second axial member wall means. The first and/or second axial member wall means comprises a substantially planar wall. The substantially planar wall is perpendicular to the central axis 1028.

[0480] The first and/or second axial member/s 1112a, 1114a is configured to rotate relative to the central axis 1028. The first and/or second axial member/s 1112a, 1114a is configured to rotate about the central axis 1028.

[0481] The first and/or second axial member/s 1112a, 1114a is rotatable and/or axially displaceable relative to the other of the second or first axial member 1112a; and/or relative to the inner member and/or the outer member 1146, 1142.

[0482] The device 1110 is configured to axially displace the first axial member 1112a relative to the second axial member 1114a according to a rotational position of the first and/or second axial member/s 1112a, 1114a.

[0483] The device 1110 is configured to displace the first axial member 1112a in a first axial direction according to a rotational position of the first axial member 1112a.

[0484] The first and second axial member/s 1112a, 1114a are rotatably fixed relative to the other of the second or first axial member; and relative to the inner member 1146 in the embodiment shown. The first and second axial members 1112a, 1114a are keyed to the inner member 1146 in the embodiment shown.

[0485] The first and second axial members 1112a, 1114a are configured to move rotationally and axially relative to the outer member 1142. The first and second axial members 1112a, 1114a are configured to move axially relative to the inner member 1146. The first and second axial members 1112a, 1114a are configured to move in antiphase with each other. In the embodiment shown, the first axial member 1112a is configured to move up whilst the second axial member 1114a moves down; and vice versa. In other embodiments, the first and second axial members 1112a, 1114a are configured to move in phase with each other.

[0486] The device 1110 is configured to translate the first axial member 1112a in a first axial direction and the second axial member 1114a in a second axial direction during rotation or at least one phase or cycle of a rotation of the first and/or second axial member/s 1112a, 1114a. The device 1110 is configured to translate the first axial member 1112a in a first axial direction and the second axial member 1114a in a second axial direction during all phases or cycles or rotations of the first and/or second axial member/s 1112a, 1114a. The first and second axial directions are opposite. In other embodiments, the first and second axial directions is the same.

[0487] In the embodiment shown the first and second axial members each comprise a respective cam and cam track arrangement. The first axial member 1112a comprises a first cam and cam track arrangement 1112b, 1114b. The second axial member 1114a comprises a second cam and cam track arrangement 1112b, 1114b.

[0488] The rotation of the first and/or second axial member/s 1112a, 1114a is defined by the cam arrangement/s.

[0489] The cam arrangement/s is defined win or within or adjacent the fluid chamber 1120. The cam arrangement/s comprises the first and/or second axial member wall means.

[0490] In the embodiment shown, the cam arrangement/s is distal to the fluid chamber 1120. The cam arrangement/s is separated from the fluid chamber 1120. The cam arrangement/s is sealed from the fluid chamber 1120.

[0491] The rotation of the second axial member 1114a is defined by the second cam arrangement. The rotation of the first axial member 1112a is defined by the first cam arrangement. The first and second cam arrangements are coordinated. The first and second cam arrangements are axially and rotationally aligned.

[0492] The first and second cam arrangements are in antiphase. The first and second cam arrangements are configured to provide or impart a substantially opposite axial motion to the respective second and first axial members 1114a, 1112a. The first and second cam arrangements comprise or define motions of substantially similar amplitudes. The first and second cam arrangements comprises or define motions of substantially similar frequency.

[0493] In alternative embodiments, the first and second cam arrangements comprise or define motions of different amplitudes and/or different frequencies, wherein one frequency is a multiple of another frequency. For example, the first cam arrangement defines a first frequency of motion of the second axial member 1114a and the second cam arrangement defines a second frequency of motion of the first axial member 1112a. The first frequency is a multiple of the second frequency. For example, the first frequency is twice that of the second frequency. Accordingly, the second axial member 1114a is axially displaced or stroked at twice the rate of the first axial member 1112a. The first and second frequencies is selected such as to vary a volume of the fluid chamber 1120.

[0494] The first axial member 1112a is configured to axially displace at a similar frequency and/or rate as the second axial member 1114a.

[0495] The/each cam arrangement comprises a cam track 1112b and a cam follower 1114b. In the embodiment shown, the first and second axial members 1112a, 1114a comprise the cam tracks 1112b. The outer member 1142 comprises the cam follower 1114b.

[0496] The device 1110 comprises a plurality of cam followers 1114b and a plurality of cam tracks 1112b. Each cam arrangement comprises a plurality of cam followers 1114b and a plurality of cam tracks 1112b.

[0497] The plurality of cam followers 1114b is configured to engage and/or cooperate and/or correspond to the plurality of cam tracks 1112b. Providing a plurality of cam tracks 1112b and/or cam followers 1114b may allow the/each cam track and/or the/each cam follower to carry a reduced load. The plurality of cam tracks 1112b and/or plurality of cam followers 1114b is configured to provide an increased pressure and/or increased force and/or increased strain and/or increased stress threshold/s to the device 1110.

[0498] The plurality of cam followers 1114b and/or plurality of cam tracks 1112b is axially and/or radially arranged. The plurality of cam followers 1114b and plurality of cam tracks 1112b is axially and radially evenly or symmetrically distributed.

[0499] In the embodiment shown, the cam tracks 1112b comprises one or more slot/s, recess/es and/or groove/s and the cam follower 1114b comprises a protrusion/s or projection/s for cooperation with the one or more slot/s, recess/es and/or groove/s. The protrusion/s or projection/s comprises a pin/s, a boss/es, a flange, a raised profile, or the like.

[0500] The first axial member 1112a comprises a first axial member wall means. The first axial member 1112a wall means comprises a first cam track wall means. The first axial member 1112a comprises the plurality of cam tracks 1112b. The first axial member 1112a comprises the plurality of first cam track wall means.

[0501] The second axial member 1114a comprises a second axial member wall means. The second axial member 1114a wall means comprises the first cam follower wall means. The second axial member 1114a comprises the plurality of cam followers 1114b. The second axial member 1114a comprises the plurality of first cam follower wall means.

[0502] The first and second axial member/s 1112a, 1114a comprises a cam and cam track arrangement. The first axial member 1112a comprises a first cam and cam track arrangement. The second axial member 1114a comprises a second cam and cam track arrangement.

[0503] The first and second cam track 1112b and cam follower 1114b arrangements are axially and rotationally aligned. The first and second cam track and cam follower arrangements are in antiphase.

[0504] In the embodiment shown the first axial member 1112a acts as a piston in a first chamber 1120 and a cylinder head in a second (adjacent) chamber 1120. The outer member 1142 comprises the cam follower 1114b. In the embodiment shown, the first inner member 1146 is driven such that the first axial member 1112a with the cam track 1112b rotates relative to the outer member 1142 with the cam follower 1114b. It will be appreciated that in other embodiments, the inner member 1146 or the first axial member 1112a comprise the cam follower 1114b and/or the first axial member 1112a may comprise the cam track 1112b.

[0505] In the embodiment shown, the first axial member 1112a of the device 1110 shown defines or forms part of a second axial member 1114a of a second device (not fully shown). The second axial member 1114a of the first device 1110 defines or forms part of a first axial member 1112a of a third device (not fully shown). In the embodiment shown, the first and second axial members 1112a, 1114a are configured to move rotationally and axially relative to the outer member 1142. The first and second axial members 1112a, 1114a are configured to move in antiphase with each other. Each device 1110 comprises a plurality of cam followers 1114b and a plurality of cam tracks 1112b. The plurality of cam followers 1114b is configured to engage and/or cooperate and/or correspond to the plurality of cam tracks 1112b. Each of the plurality of cam tracks 1112b of each device 1110 is substantially parallel. Each of the plurality of cam tracks 1112b of each device 1110 is relatively fixed, In the embodiment shown, the plurality of cam tracks 1112b of adjacent devices 1110 is in antiphase.

[0506] Providing a plurality of cam tracks 1112b and/or cam followers 1114b allows the/each cam track 1112b and/or the/each cam follower 1114b to carry a reduced load. The plurality of cam tracks 1112b and/or plurality of cam followers 1114b is configured to provide an increased pressure and/or increased force and/or increased strain and/or increased stress threshold/s to each device 1110.

[0507] The plurality of cam followers 1114b of each device 1110 are axially and radially arranged. The plurality of cam tracks 1112b of each device 1110 are axially arranged. In the embodiment shown, each device 1110 comprises three substantially parallel cam tracks 1112b. The plurality of cam followers and/or plurality of cam tracks is axially and radially evenly or symmetrically distributed.

[0508] The apparatus 1105 is configured to synchronise the opening and/or closing of the inlet/s 1122 and/or outlets 1124 of the respective devices 1110. In the embodiment shown, the outlet 1124 of a first device 1110 is closed whilst the outlet 1124 of an adjacent device 1110 is open. Accordingly, it is assured that fluid does not flow from the chamber 1120 of the first device 1110 into the chamber 1120 of the second device 1110. In alternative embodiments, the plurality of devices 1110 is connected such that all outlets 1124 are simultaneously opened and closed.

[0509] The plurality of devices 1110 is connected such that the inlets 1122 and outlets 1124 of respective (adjacent) devices 1110 are sequentially opened and closed. Accordingly, an output of the apparatus 1105 is smoothed across a complete cycle (such as a full rotation of an inner or outer member 1146, 1142).

[0510] The plurality of devices 1110 are mounted to a common member/s. In the embodiment shown, the apparatus 1105 comprises a single common first inner member 1146. In the embodiment shown, the apparatus 1105 comprises a single common first outer member 1142. In the embodiment shown, the apparatus 1105 comprises a single common second inner member 1147.

[0511] In the embodiment shown, the first inner member 1146 comprises a hollow drive shaft for rotatably driving the first and second axial members 1112a, 1114a. The apparatus 1105 comprises a further or second inner member 1147. The further or second inner member 1146 comprises a shaft, which is also hollow in the embodiment shown. The further or second inner member 1147 comprises a fluid conduit. The further or second inner member 1147 comprises a second inner member throughbore 1150. The further or second inner member 1147 is mounted or provided in or within the first inner member 1146. The further or second inner member 1147 is mounted coaxially and/or concentrically with the first inner member 1146. The first inner member 1146 is relatively rotatable with respect to the further or second inner member 1147. The first and second inner members 1146, 1147 are mounted in a tight fit. The first and second inner members are mounted so as to substantially prevent a fluid passage between the first and second inner members 1146, 1147. The first and second inner members 1146, 1147 are mounted so as to substantially eliminate any fluid passage between an outer surface of the second inner member 1147 and the inner surface of the first inner member 1146. The first inner member 1146 defines an outer sleeve. The second inner member 1147 defines an inner sleeve. In the embodiment shown, the first and second inner members 1146, 1147 are relatively rotatable to selectively open and close the fluid outlets 924. In other embodiments (not shown), the first and second inner members 1146, 1147 are relatively rotatable to selectively open and close the fluid inlets 1122. The first and second/further inner members 1146, 1147 comprises apertures or openings 1123, 1125. The apertures or openings 1123, 1125 of the first and second/further inner members are configured to align to open the fluid inlets 1124.

[0512] The apertures or openings 1123, 1125 of the first and second/further inner members are configured to periodically align, such as during predetermined phases or positions of a relative rotation between the first and second inner members 1146, 1147. In the embodiment shown, the first inner member 1146 comprises fewer openings or apertures 1123 than the second inner member 1147. In the embodiment shown, the inner member 1147 comprises a single opening or aperture 1123 and the second/further inner member 1147 comprises a plurality of apertures/openings 1125. In alternative embodiments, the first inner member 1147 comprises a similar number and/or arrangement of opening/s or aperture/s 1123 as the second inner member 1147. In alternative embodiments, the first inner member 1146 comprises a plurality of apertures or openings 1123 and optionally more openings or apertures 1123 than the second inner member 1147.

[0513] In other embodiments, the apparatus 1005 is configured to use an output of a first device 1110 as an input to a second device 1110. A first device 1110 is configured to provide an input to a second device 1110. For example a motor is configured to provide a mechanical input to a pump.

[0514] The fluid chambers 1120 of the plurality of devices are separated by a seal, which is by an O-ring in the embodiment shown.

[0515] FIGS. 105 to 113 show cross-sectional views of the portion of the apparatus of FIGS. 89 to 104 in sequential configurations illustrating the sequential alignment and misalignment of the openings or apertures 1123, 1125 of the respective first and second inner members 1146, 1147 to sequentially open the outlets 1124 into the throughbore 1150. Similarly, the apertures 1133 of the projections 1131 sequentially align and misalign with the inlets 1122 to sequentially allow fluid into the chamber 1120 and alternately block the inlets 1122.

[0516] It will be appreciated that any of the aforementioned apparatus may have other functions in addition to the mentioned functions, and that these functions may be performed by the same apparatus.

[0517] The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention. For example, where an attribute or feature has been described in relation to a cam follower or track, it will be appreciated that the attribute or feature could be applied to the other of the cam follower or track. For example, where the cam follower is described as closing an inlet or outlet, in other embodiments the cam track may close the inlet or outlet. Similarly, where features are described in relation to the second axial member, it will be appreciated that those features may be additionally or alternatively attributed to the first axial member.