GB2324340A

GB2324340A - Rotary vane pump or motor

Info

Publication number: GB2324340A
Application number: GB9626086A
Authority: GB
Inventors: Waldo Belmonte Zbinden
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-12-16
Filing date: 1996-12-16
Publication date: 1998-10-21
Also published as: GB9626086D0

Abstract

A rotary vane pump or motor comprises a housing (10) containing a rotor (5) and having fluid inlet and outlet means (37,38). The rotor (5) supports a number of displaceable vanes (9) or vane members (9') which progress around the inner wall surface (94) of a cylindrical member (1) surrounding the rotor (5) and adopting an eccentric position relative to the rotor (5). An eccentric space (20) between the rotor (5) and the wall surface (94) is axially delimited and is separated into diametrical opposed working chambers with the aid of divergent wall portions (2) of wall structures (50) mounting to the cylindrical member (1) for movement therewith to form a regulator (18) or provided in a fixed position on a cover (16) and an opposed end wall of the housing. Windows or openings between radial faces (19) of the wall portions (2) control the flow or fluid and at least the cylindrical members (1) is positionally adjustable to vary the relative sizes of the working chambers and to regulator the flow rate and its direction of flow.

Description

APPARATUS IN ThE FORM OF A ROTARY VANE PUMP OR MOTOR The present invention relates to apparatus usable as a pump or a motor of a type which employs a rotor with a number of vanes, usually radially displaceable vanes, which are propelled around an axis which is eccentric in relation to a wall in a housing. The passage of the vanes through an eccentric space within the wall in the housing causes the volume of the space between successive vanes to be progressively increased and decreased in a similar manner to a piston in a cylinder.

In the case of a pump the vanes thus induce fluid to flow into and out from the housing.

A general object of the present invention is to provide an improved form of apparatus.

As is known, apparatus constructed in accordance with the invention comprises a housing, inlet means for admitting fluid into the housing, outlet means for discharging fluid from the housing, and a rotor with displaceable vanes or vane members disposed for rotation inside the housing. A cylindrical member having an inner wall surface surrounding the rotor is in confronting relationship with radial extremities of the vanes and adopts an eccentric relationship to the axis of rotation of the rotor.

In accordance with the invention there is provided means for defining working chambers in diametrically opposed relationship, which communicate with the inlet and outlet means as the rotor rotates, the defining means comprising part of the inner wall surface of the cylindrical member and divergent wall portions in axial confiontation with the rotor, said wall portions having radial faces spaced apart by an arcuate distance at least equal to the effective distance between radial extremities of an adjacent pair of the vanes or vane members which serves to control the flow of fluid and an adjustable regulator at least including the cylindrical member which can be positionally adjusted to vary the rate of fluid flow passing from the inlet means to the outlet means and to reverse the direction of fluid flow.

Preferably the rotor vanes are provided with guide means to control their displacement. Where the vanes are radially displaceable the guide means in one form comprises a ring supported by radial extremities of the vanes or a series of arcuate ring segments each supported by the radial extremity of one of the vanes.

In the latter case the guide means preferably further comprises arms or the like projecting axially of the vanes and locating within a channel disposed radially inwardly of the vanes relative to their extremities.

In other embodiments the vane members are supported for pivotable movement on the rotor and the guide means takes the form of curved contact surfaces on the rotor which slidably contact head pieces of the vane members which swing in and out relative to the wall surface of the cylindrical member.

The wall surface of the cylindrical member opposite the rotor can be an inner peripheral surface of the cylindrical member which is eccentric in relation to its outer peripheral surface. In an analogous arrangement the wall surface of the cylindrical member opposite the rotor vanes is defined by the inner peripheral surface of a regular cylindrical member which has a central axis offset in relation to the rotary axis of the rotor.

The divergent wall portions defining the working chambers can be formed by end plates of the regulator which are integral with or fixed to the cylindrical member to generally surround the rotor and which is adjustable in a rotational position to adjust the operating characteristic of the apparatus.

Where the apparatus is used as a pump the rotor is driven at constant speed and the adjustment can regulate the flow of fluid. The flow can be regulated from one extreme where no fluid is discharged from the outlet means to another extreme where a maximum rate of fluid flow is discharged from the outlet means. The flow can also be reversed in direction so the inlet and outlet means reverse roles. It is desirable in some applications to provide a mechanism or device external to the housing to effect the adjustment of the regulator but in other cases the characteristics can be pre-set on manufacture.

In all embodiments of the invention the adjustable cylindrical member is associated with the wall structures with the characteristic radially divergent regions. The radial surfaces of these regions then act to regulate the fluid flow.

The wall structures can be provided on end plates shaped like bow ties fixed to the cylindrical member so as to move with the regulator. In other embodiments the wall structures are fixed and provided on components of the housing, such as an end wall and removable cover and the cylindrical member is then shaped in an eccentric fashion with only the axis of its outer surface co-incident with the axis of the rotor.

The vanes or vane members of the rotor may be carried by or mounted in slots in a hub of a rotor coupled to a shaft which is driven by external power when the apparatus functions as a pump. The vanes may be provided with axial projections or arms which locate with rolling or sliding bodies in one or more channels or which locate directly in the channel or channels. In such embodiments the contact ring or arcuate ring segments may be omitted. One or more floating rings can be sued to guide the displacement of the vanes or vane members.

The invention may be understood more readily, and various other aspects and features of the invention may become apparent, from consideration of the following description.

Embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings wherein: Figure 1 is a perspective view of apparatus constructed in accordance with the invention; Figure 2 is a perspective view of part of the interior components of the apparatus shown in Figure 1 and including the fluid flow regulator; Figure 3 is part sectional side view of the apparatus shown in Figures 1 and 2; Figure 4 is a part-sectional end view of the apparatus shown in Figures 1 to 3; Figure 5 is a perspective view of part of the apparatus with a modified regulator; Figure 6 is a part-sectional end view of another modified construction for the apparatus; Figure 7A is a sectional side view of part of a further modified apparatus; Figure 7B is an end view of the part of the apparatus shown in Figures 7a the view being taken along the line VII-MI in Figure 7a; Figure 8 is a part sectional side view of another embodiment of apparatus constructed in accordance with the invention; Figure 9 is an end view of the apparatus shown in Figure 8; Figures 10 & 11 are part sectional end views of the apparatus shown in Figures 8 and 9 depicting the regulator in different operating positions; Figure 12 is a perspective view of the cover of the apparatus shown in Figures 8 to 11; Figure 13 is an end view of a modified form of the apparatus shown in Figures 8 to 12; Figure 14A is an end view of part of a modified form of the apparatus shown in Figures 8 to 12; Figure 14B is a part sectional side view of part of the apparatus shown in Figure 14a; Figure 1 5A is an end view of the interior of another apparatus constructed in accordance with the invention; Figure 1 5B is a sectional side view of part of the apparatus shown in Figure 15A, and Figure 16 is diagrammatic representation of part of the apparatus depicted in Figures 15A and 15B.

In the following description reference is made to the apparatus constructed in accordance with the invention as being in the form of a pump in which case motive power is delivered to a drive shaft of the apparatus in order to cause fluid to pass from an inlet to an outlet. It is however possible to use the apparatus as a motor in which case the fluid flow is used as the motive power and the output is taken from an output shaft. Thus it is to be understood that in the following description reference is made throughout to the apparatus in the form of a pump simply for convenience.

As shown in Figure 1, a pump constructed in accordance with the invention has a housing 10 mounted on a base plate 43. Manifolds with flanged pipes 37 and 38 lead to the interior of the housing 10 from diametrically opposite regions and provide an inlet and an outlet for fluid. A drive shaft 6 leads into the housing 10 from one end and a regulator shaft 4 leads in to the housing 10 from an opposite end via a removable cover 16 fixed with bolts to the housing 10.

Figures 2,3 & 4 depict a rotor 5 drivably coupled to the shaft 6 which has a rotary axis K. The rotor 5 employs a number of radially displaceable plate-like vanes 9 which are guided in slots 8 in a hub 92 fixed to the shaft 6 and move around a wall surface 94 in the housing 10 as the shaft 6 rotates. Since the rotor 5 is eccentric in relation to the wall surface 94 the vanes 9 move progressively closer to and then further away from the axis K as is known. As the vanes 9 move out of the slots 8 fluid can enter the slots 8 and would be subjected to pressure and/or expelled as the vanes 9 move inwardly again. To avoid this, it is desirable to provide a pair of depressions 105 in the hub 92 as shown in Figure 3 to act as relief chambers and to allow the fluid to pass freely in and out of the slots 8.

In this embodiment the outer extremities of the vanes 9 are in contact with a ring 7 which forms a common contact surface for the vanes 9.

As can be seen in Figure 4 the pipe 37 defines a sub-chamber D and the pipe 38 defines a sub-chamber C. The chambers C, D each communicate with an eccentric segmental space 20 which progressively increases and decreases in volume as the rotor 5 rotates and the vanes 9 progress around. This changing volume induces fluid to flow from one pipe 37,38 to the other pipe 38,37 depending on the direction of rotation of the rotor 5.

The shaft 4 can be displaced to vary or regulate the fluid flow through the pump. Figure 1 depicts a handle 14 for adjusting the shaft 4 or as an alternative a device 32 with a handle and a worm mechanism. The shaft 4 is coupled to a regulator 18 which takes the form of an outer cylindrical member 1, the inner periphery of which provides the wall surface 94, and a pair of end plates 50. The end plates 50 resemble a bow tie each with a part circular inner portion 3 adjoining outwardly divergent wall portions or regions 2. The shaft 4 is secured to the inner portions 3 of the end plates 50. The regions 2 of the end plates 50 are secured with bolts to the member 1. As can be seen in Figure 3 the end plates 50 of the regulator 18 and the member 1 generally surround the rotor 5 and retain the ring 7 and the rotor 5 in place. The outer periphery of the ring 7 and the inner periphery of the member 1 of the regulator 18 providing the wall surface 94 are coaxial with the shaft 4 and are in closely confronting relationship or in sliding contact. The inner periphery of the ring 7 and the outer periphery of the hub 92 confront the wall surface 94 defined by the inside of the member 1 and are eccentric relative to the surface 94 to define the eccentric space 20.

The wall portions or regions 2 of the end plates 50 can combine with correspondingly enlarged portions 51 of the member 1 to form bodies A and B which slide and seal with respect to the inner wall of the housing 10. The end plate 50 of the regulator 18 opposite the shaft 4 forms a lining for the end wall of the housing 10 nearest the drive shaft 6 as shown in Figure 3. This end plate 50 is supported by a bearing 12 on an inwardly extending shoulder 52 ofthe housing 10.

The end plate 50 of the regulator 18 nearest the shaft 4 extends alongside the cover 16. The radial side faces 19 of the wall regions 2 of the end plates 50 and the portion 3 of the end plates 50 define openings W communicating with the chambers C and D. The chambers C, D communicate via two diametrically opposed working chambers and the eccentric space 20. When the apparatus is operating as a pump the chamber C can be at lower pressure where fluid is admitted and the chamber D at higher pressure wherefrom fluid is discharged. If the fluid flow is reversed however the roles of the chambers C,D are likewise reversed. The chambers C, D are separated by the wall portions 32 which are in close proximity to the housing end wall 17 and the cover 16 and to the rotor 5.

The end plates 50 also locate and provide guidance for the vanes 9. The divergent wall regions 2 of the end plates 50 of the regulator 18 preferably each extend over an arcuate distance at least equal to the spacing between two adjacent vanes 9 and has its radial surfaces 19 conforming to the radial position of the vanes 9. As the vanes 9 move over an opening W and pass a radial face 19 to enter the eccentric space 20 fluid is induced to flow. As the vanes 9 move away from a radial surface 19 and progress along the openings W they do not perform any work on the fluid. The transmission of energy from the pump to the fluid is performed when the vanes 9 and the fluid pass inside the working chambers. The relevant cross-sectional working areas of the working chambers for different operating positions of the regulator 18 are denoted by the cross-hatch lines Al, A2, Bl, B2 in Figure 4. Since the regulator 18 can be moved with the shaft 4 the size of the working areas Al, A2, BI, B2 can be varied and this in turn adjusts the flow rate of the fluid passed through the pump.

As shown in Figure 3, the shaft 6 is rotatably supported by bearings 15 in an outer axial projection 95 of the housing 10. Similarly the shaft 4 is rotatably supported by a bearing 11 in a spigot 96 of the cover 16. Seals 13 are provided around the shafts 4,6 to seal off the interior of the housing 10. The shaft 4 can be partly rotated to move the regulator 18 in a clockwise or anticlockwise sense but let it be assumed that the rotor 5 is revolving clockwise whilst the regulator 18 is adjusted anti-clockwise. As the rotor 5 moves centrifugal forces urge the vanes 9 outwardly into fictional contact with the ring 7. The vanes 9 thus lock against the ring 7 and force the ring 7 to rotate with the vanes 9 about the axis of the drive shaft 6.

Figure 4 depicts two extreme positions adopted by the regulator 18 and the shaft 4. In the position Al, B1 the working areas are the same size and the quantity of fluid passing from chamber C to D as the same as the fluid passing from D to C. The fluid thus circulates inside the pump and no fluid passes between the pipes 37 and 38. This is an idling mode.

In the position A2, B2 the area A2 is much smaller than the area B2 and fluid will now progress from chamber D to the chamber C and the fluid flow rate between the pipes 38, 37 is at a maximum. By moving the regulator 18 back clockwise from A2, B2 back to Al, B1 the working area A increases in size while the working area B decreases so that the flow rate diminishes.

Since the radial faces 19 are exposed to self compensatory pressure and since the regulator 18 is supported by bearings 11, 12 the fluid flow and the circulation of the fluid within the pump will not displace the regulator 18.

In a modified arrangement the end plate 50, adjacent the end wall 17 of the housing 10, is combined in one-piece with the cylindrical member 1.

Figure 5 depicts a modified form for the regulator 18 where the member 1 has an increased axial dimension and where the end plate 50 adjacent the end wall 17 is integral with the member 1. In this case a part circumferential slot 23 is provided within the member 1 and accordingly two spaced apart rings 7 are provided instead of one ring 7.

In Figure 6 the vanes 9 are provided with axially projecting arms 22 which locate in channels 25 in the inner portions 3 of the end plates 50 of the regulator 18. The ring 7 in this construction is sub-divided into arcuate shoes 24 and shallow depressions in the shoes 24 locate with the respective vanes 9. The channels 25 and the arms 22 guide the radial displacement of the vanes 9 In Figure 7A and 7B, the external ring 7 or shoes 24 is or are omitted and to prevent the vanes 9 making direct contact with the interior of the member 1 the vanes 9 engage with rolling or sliding members 33 held by the arms 22 and engaging in the channels 25 as before.

Figures 8 to 12 depict another embodiment of a pump in which the fluid flow is variable and also reversible. For convenience the necessary seals are omitted from these Figures 8 to 12 and like reference numerals denote like parts to the other Figures 1-7. In this form of the pump, the drive shaft 6 supported by bearings 15 carries the rotor 5 with vanes 9 as before but the regulator 18 has a cylindrical member 1 with an eccentric peripheral inner surface 94 partly defining the eccentric space 20. The axes of the regulator 18 and the rotor 5 are coincident.

The member 1 has an outer peripheral surface which is located against the inner wall ofthe housing 10 for rotation but not for axial or radial displacements. In this embodiment, the member 1 is separated from the divergent wall regions 2 and the inner wall portions 3 defining the openings W. In this construction the wall portions 3 and the wall regions 2 are formed integrally with the end wall 17 of the housing 10 and integrally with the cover 16 as depicted in Figures 8 and 12.

Figure 9 shows a mechanism 29 for adjusting the rotary position of the member 1. The mechanism 29 is coupled to a worm 28 which meshes with a toothed outer rim of the member 1. The member 1 can be displaced through at least 1800 and Figures 10 and 11 show different positions where the member 1 has been displaced through 90" In this case the centre of the inner periphery of the member 1 adopts the eccentric positions denoted E and F relative to the axis of the rotor 5. The eccentric space 20 essential to the operation of the pump, is here formed between the interior wall surface 94 of the member 1 and the effective outer surface of the rotor 5 and the vanes 9 progress around the inner surface of the member 1. The vanes 9 again move out to lock against a rotatable ring 7 due to centrifugal force and the eccentric space 20 extends over the ring 7.

It is desirable to ensure the axial dimensions of the member 1, the ring 7 and the vanes 9 are the same.

As before the working bodies are denoted A and B and the working areas Al,B1,B2,A2inFigures 10 and 11.

Assume the rotor 5 is propelled clockwise and the member 1 is moved anticlockwise. The vanes 9 are urged by centrifugal forces to carry the ring 7 and move around the eccentric space 20 and the operation is similar to that described previously.

Figure 10 shows the eccentric space 20 at the bottom where the working areas A2,B2 are dis-similar in size to a maximum extent and maximum fluid flow rate is established as the fluid flows from the chamber D to the chamber C.

Figure 11 shows the opposite situation where the working areas Al, B 1 are the same and where the fluid circulates and does not pass between the chambers D and C. If the member 1 is rotated through 1800 from the position shown in Figure 10 these areas are reversed and A2 is larger than B2. In this situation the flow is reversed and passes from chamber C to chamber D. It therefore follows that the flow rate and the direction of flow can be controlled by moving the member 1 with the mechanism 29.

Figure 13 depicts a modified arrangement where the vanes 9 have axial arms 22 and the ring 7 is sub-divided into arcuate portions or shoes 24 as in the Figure 6 arrangement. In this case however, the arms 22 engage between inner and outer rings 26,27. Such an arrangement permits the ring 7 or the shoes 24 to be omitted.

Figure 12 shows a channel 31 in the wall portion 3 which is useful in the arrangements shown in Figures 14A and 14B where the arms 22 carry rotary or sliding bodies 33 which engage on an inner floating ring 26. The ring 26 and the bodies 33 are accommodated in the channel 31.

Figures 15A and Figure 15B depict a modified apparatus which has an entirely different form of construction and guidance for the vanes 9. In this construction the vanes 9 are not guided for radial movement but are represented by vane members 9' mounted for arcuate pivotal movement. Otherwise in Figures l5A, 15B and 16 like reference numbers demote like parts to the previously description embodiments.

The vane members 9' are depicted more clearly in Figure 16 where it can be seen that each member 9' has a lozenge-shaped head piece 40 adjoining a shank 42 and a mounting block 44 opposite the head piece 40. The block 44 has a bore 46 which receives a pin 45 pivotably supporting the vane member 9' in an aperture in a rib 48 extending radially outwards from the hub 92 of the rotor 5. The ribs 48 each have curved Sank surfaces 49 which slidably engage with the associated outer surfaces 30 of the head pieces 40 to guide the vane members 9' as they pivot about the axes of the pins 45. The radially outer faces 17 of the head pieces 40 slidably contact the wall surface 94 of the cylindrical member 1 of the regulator 18 in the housing 10 as shown in Figure 15A.

The interior wail 17 of the housing 10 and the cover 16 again have divergent wall regions 2 as in the previous embodiments which extend between two adjacent vane members 9'. To keep the faces 17 of the head pieces 40 in contact with the wail surface 94 one or more preferably several floating rings 27 are again provided between the rotor 5 on the one hand and the end wall 17 of the housing 10 and the cover 16 on the other hand as depicted in Figure 15B.

The axial length of the head pieces 40 is equal to the combined width of the rotor 5 and the rings 27 as shown in Figure 15B.

The end faces 21 of the head pieces 40 are thus in sliding contact with the inner side of wall portion 3 and the divergent wall regions 2 of the end wall 17 of the housing 10 and the cover 16.

Since the wall surface 94 is eccentric there is an eccentric gap 20 between the surface 94 and the outer periphery of the rotor 5. The member 1 is again rotatable with respect to the housing 10 and as in the previous embodiments the member 1 can have a toothed rim which meshes with a worm 28 as shown in Figure 10 to control the operational characteristics of the apparatus. As the rotor 5 is rotated the outer surfaces 17 of the head piece 40 progress along the surface 94 and the vane members 9' pivot about the pins 45 to move away from or towards the rotor 5.

In this construction the divergent wall portions 3 and the end regions 2 are again integral with the end wall 17 and the cover 16 so they are fixed in position.

However, as the member 1 is partially rotated by means of the worm 28 the volume of the working chambers can be varied to control the flow rate and the direction of fluid flow as before. The embodiment represented by Figures 1 SA, 15B and Figure 16 is more suitable for use with fluid at higher pressure.

Although in the apparatus as described means 14, 32, 29 is provided for causing the flow rate of the fluid to be adjusted it is possible to omit the adjustment means from the exterior of the housing 10. In this case the regulator 18 is preset on manufacture to provide a predetermined flow rate. Access to the regulator 18 for adjustment can then be made by removing the cover 16.

As mentioned previously it is possible to make the apparatus as described function as a motor by using the fluid flow as the motive power and the shaft 6 then provides an output which can be controlled at different speeds depending on the regulation of the fluid flow rate.

In one application the pump as described and illustrated is combined in a drive system with an hydraulic motor which may be controlled with the pump.

Claims

1. Apparatus usuable as a pump or motor and comprising: a housing; inlet means for admitting fluid into the housing; outlet means for discharging fluid from the housing; a rotor with displaceable vanes or vane members mounted for rotation within the housing; a cylindrical member with an inner wall surface surrounding the rotor which adopts an eccentric relationship to the axis of rotation of the rotor; means defining working chambers in diametrically opposed relationship, which communicate with the inlet and outlet means as the rotor rotates, the defining means comprising part of the inner wall surface of the cylindrical member and divergent wall portions in axial confrontation with the rotor, said wall portions having radial faces spaced apart by an arcuate distance .at least equal to the effective distance between radial extremities of an adjacent pair of the vanes or vane members which serves to control the flow of fluid and an adjustable regulator, at least including the cylindrical member, which can be positionally adjusted to vary the rate of fluid flow passing from the inlet means to the outlet means and to reverse the direction of fluid flow.

2. Apparatus according to claim 1, wherein adjustment of the regulator causes the relative volumes of the working chambers to change.

3. Apparatus according to claim 2, wherein adjustment of the regulator also causes the rotational disposition of the working chambers to change.

4. Apparatus according to claim 1,2 or 3, wherein the rotor vanes are radially displaceable and support a ring or a series of arcuate ring segments held in regular spaced relationship to the wall surface of the cylindrical member or sliding contact therewith.

5. Apparatus according to claim 1,2 or 3, wherein the rotor carries pivotable vanes members with head pieces guided for movement towards and away from the wall surface ofthe cylindrical member.

6. Apparatus according to any one of claims 1 to 5, wherein the regulator is adjustable from the exterior of the housing.

7. Apparatus according to any one of claims 1 to 6, wherein the regulator further comprises a pair of end plates with the divergent wall portions with radial faces defining openings communicating with the working chambers and adjustment of the regulator displaces the divergent wall portions.

8. Apparatus according to claim 7, wherein the end plates are fixed to the cylindrical member or integral therewith and are supported on a rotatable shaft forming part of the regulator.

9. Apparatus according to any one of claims 1 to 6, wherein the divergent wall portions define openings communicating with the working chambers and the wall portions are fixed in position.

10. Apparatus according to any one of claims 1 to 9, wherein the cylindrical member has an outer wall surface located in the housing and the inner and outer wall surfaces are eccentric in relation to one another.

11. Apparatus according to any one of claims 1 to 9, wherein the cylindrical member has a regular cylindrical shape with a central axis offset in relation to the axis of rotation of the rotor.

12. Apparatus according to claim 4 or any on of claims 5 to 11 when appended to claim 4, wherein the vanes are slidably displaceable in slots in a hub of the rotor coupled to a drive output shaft or drive input shaft.

13. Apparatus according to claim 12 wherein the slots communicate with at least one pressure relief chamber which permits fluid to pass in and out of the slots as the vanes are displaced therein.

14. Apparatus according to claim 4 or 12 or 13 or any one of claims 5 to 11 when appended to claim 4, wherein the vanes are provided with axially projecting arms and the arms are guided directly or indirectly in a channel.

15. Apparatus according to claim 5, or any one of claims 6 to 11, when appended to claim 5, wherein the rotor has a hub coupled to a drive output shaft or input shaft and the hub has spaced apart radial ribs which support the vane members for pivotal movement, the ribs having curved faces for slidably contacting and guiding the head pieces of the vane members.

i6. Apparatus according to claim I and further comprising guide means to control the displacement of the vanes or vane members.

17. Apparatus according to claim 16 wherein the vanes are radially displaceable and the guide means at least includes a ring supported by radial extremities of the vanes or a series of arcuate ring segments each supported by the radial extremity of one of the vanes.

18. Apparatus according to claim 16, wherein the guide means at least includes arms on the vanes extending axially of the rotor, the arms engaging directly or indirectly into one or more channels.

19. Apparatus according to claim 18, wherein the arms carry rotatable or sliding bodies fitted into the associated channel or channels.

20. Apparatus according to claim 19, wherein the channel or one of the channels is defined between a pair of rings.

21. Apparatus according to claim 19, wherein the channel or one of the channels is formed in a cover for the housing and a floating ring is fitted in the channel in contact with the rotatable or sliding bodies.

22. Apparatus according to claim 19, wherein there are two channels formed in or by end plates of the regulator which also provides the divergent wall portions.

23. Apparatus according to any one of the claims 16 to 22, wherein the rotor has slots slidably locating the vanes and the interiors of the slots communicate with at least one pressure relief chamber permitting fluid to pass in and out of the slots as the vanes are radially displaced.

24. Apparatus according to claim 16, wherein the vane members are each mounted to the rotor for pivotal movement about one end and have a shaped headpiece at the opposite end which moves towards or away from the inner wall surface of the cylindrical member and the guide means comprises slidable contact surfaces on the rotor which engage with the headpieces.

25. Apparatus according to claim 24, wherein the guide means further comprises one or more floating rings.

26. Apparatus substantially as described with reference to and as illustrated in any one or more of the Figures of the accompanying drawings.

27. Apparatus according to any one of the preceding claims in the form of a pump which is combined in a drive system with a hydraulic motor driven by the pump.