CN220581100U

CN220581100U - Sliding vane pump, vane and vacuum pump

Info

Publication number: CN220581100U
Application number: CN202190000962.0U
Authority: CN
Inventors: E·菲戈尼; C·德斯佩斯
Original assignee: Laibao France Co ltd
Current assignee: Laibao France Co ltd
Priority date: 2020-11-09
Filing date: 2021-11-08
Publication date: 2024-03-12
Anticipated expiration: 2031-11-08
Also published as: DE212021000498U1; TW202225558A; WO2022096713A2; JP3244413U; GB2600784A; WO2022096713A3; KR20230001370U; GB202100752D0

Abstract

Sliding vane pumps, vacuum pumps lubricated by such pumps, and vanes for sliding vane pumps are disclosed. The sliding vane pump includes: a rotor rotatably mounted within the stator. The rotor includes at least one vane slidably mounted within a corresponding at least one cavity, at least one end face of the vane being configured to abut an inner wall of the stator. The rotor, stator and at least one vane define a plurality of variable volume pumping chambers for delivering fluid from the fluid inlet to the fluid outlet upon rotation of the rotor, the at least one vane separating adjacent pumping chambers. The pump also includes a channel configured to provide a passageway between adjacent pumping chambers.

Description

Sliding vane pump, vane and vacuum pump

Technical Field

The field of the utility model relates to sliding vane pumps, vanes for such pumps and vacuum pumps lubricated by such pumps.

Background

Sliding vane pumps are used to pump liquids, such as oil. Sliding vane pumps may be used in conjunction with vacuum pumps to lubricate the shaft and actuate the inlet valve. Such pumps operate at high rotational speeds and have a variable volume pumping chamber formed by the rotor, sliding vanes and inner wall of the stator. The variable volume pumping chamber draws lubricant into the chamber through the inlet and compresses the lubricant as it moves from the inlet to the outlet of the pump.

Cavitation problems in the fluid may occur in such pumps, particularly where the density of the fluid being pumped and the rotational speed of the rotor are high. Cavitation is a phenomenon in which rapid changes in pressure in a liquid result in the formation of small vapor-filled cavities in the lower pressure region. When the pressure in these areas increases, the bubbles collapse and can generate strong shock waves in the vicinity of the bubbles, which cause the pump to vibrate and produce noise.

Chemical resistant lubricants such as PTFE lubricants are increasingly used in vacuum pumps to pump aggressive chemicals from semiconductor chambers. These lubricants have a high density, approaching twice the density of mineral oil, and cavitation is an increasingly serious problem for such pumps.

It would be desirable to inhibit cavitation in a sliding vane pump.

Disclosure of Invention

A first aspect provides a sliding vane pump, the pump comprising: a rotor rotatably mounted within the stator; the rotor includes at least one vane slidably mounted within a respective at least one cavity, at least one end face of the vane configured to abut an inner wall of the stator; the rotor, stator and at least one vane defining a plurality of variable volume pumping chambers for delivering fluid from a fluid inlet to a fluid outlet upon rotation of the rotor, the at least one vane separating adjacent pumping chambers; and a channel configured to provide a passageway between the adjacent pumping chambers.

The inventors have recognized potential problems associated with sliding vane pumps for pumping fluids such as oil. Such pumps create a lower pressure region in which the volume of the pumping chamber increases and fluid is drawn into the pumping chamber through the inlet. The volume of the pumping chamber then decreases towards the outlet and the fluid is compressed and expelled through the outlet. In some cases, such as where the pump rotates at high speed and/or where the fluid is particularly dense, bubbles may form in the lower pressure region, and this may lead to cavitation, where bubbles formed at lower pressure collapse during fluid compression. Cavitation in the pump results in excessive noise and vibration and should be avoided where possible. Providing fluid communication channels between adjacent pumping chambers that allow fluid to flow from a higher pressure region in one pumping chamber to a lower pressure region in an adjacent pumping chamber allows excessive pressure drop in the lower pressure region to be alleviated and bubble formation to be suppressed in a simple, inexpensive and robust manner.

Although the following technical prejudices may exist: a channel allowing fluid communication between the pumping chambers cannot be provided, as this may reduce pumping efficiency and actually lead to leakage. Providing a controlled passage of predetermined, constrained dimensions such that leakage is controlled to a desired value provides an effective solution to the cavitation problem in situations where cavitation may be a problem. The passage through or around the vane may be a solution that is easy to manufacture and provides a defined channel dimension relatively independent of tolerances in the pump components.

The one or more sliding vanes are longitudinal elements mounted for sliding movement along a longitudinal axis in correspondingly shaped cavities within the rotor. This sliding motion allows the creation of a pumping chamber of variable volume when the rotor rotates eccentrically within the stator.

Although the channels providing the passage between adjacent pumping chambers may be formed in different ways, in some embodiments the channels are formed in the at least one vane.

In some embodiments, the channel comprises a groove in an end face of the vane, at least a portion of the end face abutting the stator inner wall.

A simple and convenient way of providing the channel may be to arrange it as a recess in the end face of the blade.

In some embodiments, the at least one end face is curved to provide a sealing surface with the inner wall of the stator.

The groove provides a recess in the sealing surface, the recess forming a channel through which adjacent pumping chambers are connected and providing a passageway between the leading and trailing edges of the vane during operation of the pump.

In other embodiments, the channel comprises a passage in the blade.

An alternative may be to provide the channel as a passageway extending through the blade. Since the vane is a sliding vane that extends out of the cavity in the rotor by varying amounts depending on the position of the eccentrically mounted rotor, the passageway is configured to be within a portion of the vane that is not obscured by the cavity of the rotor even when the vane is in a recessed position opposite the extended position.

Alternatively and/or additionally, the channels may comprise grooves in the inner wall of the stator.

The location of the channels may be in the rotor or in the stator wall or both, the actual location of which is not important, so long as a passageway is provided that allows some flow between the pumping chambers. The flow rate provided depends on the size of the passageway. Manufacturing the passages or grooves allows the bypass path between the chambers to be precisely controlled and relatively independent of other tolerances in the pump. The dimensions of the channels may be selected to provide a desired bypass flow sufficient to inhibit cavitation while not unduly impeding pump performance. This will depend to some extent on both the density of the fluid to be pumped and the rotational speed of the pump. Although the channels may be machined in the inner wall of the stator, it may be preferable to provide the channels in the vanes, as this may be simpler to manufacture.

In some embodiments, both end surfaces of the vane include grooves that form channels between the pumping chambers.

Although there may be a plurality of individual blades extending from individual recesses or cavities in the rotor, in some embodiments the blades may extend through the rotor, either end of the blades abutting diametrically opposed surfaces of the inner wall of the stator. The vane slides within the cavity and both ends of the vane include channels in the form of grooves.

In some embodiments, the rotor is mounted for eccentric rotation within the stator.

The centre of rotation of the rotor may be offset relative to the centre of the chamber formed by the inner wall of the stator such that when the rotor rotates its movement is eccentric relative to the inner wall of the stator.

In some embodiments, a cross-section of at least a portion of the length of the sliding vane includes a protruding portion configured to protrude from an outer surface and cooperate with a correspondingly shaped cavity in the rotor to inhibit twisting of the vane about its longitudinal axis.

In order for the blades to provide a passageway between the leading and trailing edges during rotation, the blades should be inhibited from twisting or rotating about their longitudinal axes so that the inlets to the passageway remain aligned with the pumping chambers to which they are open. This may be achieved by providing a protruding portion configured to cooperate with a correspondingly shaped cavity in the rotor. The protruding portion may extend from a longitudinally extending side surface of the blade and thus be prevented from rotating about the longitudinal axis. In some embodiments, where the channel includes a groove extending in a straight line from the leading edge to the trailing edge, the protruding portion protrudes substantially perpendicular to the groove.

Although the pump may be configured to pump a variety of fluids, in some embodiments the pump is configured to pump lubricant.

In some embodiments, the pump is configured to pump a high density lubricant having a density of greater than 1.5kg per liter.

Cavitation is a particularly prominent problem when pumps pump high density fluids, and lubricants with densities greater than 1.5 kg/liter may induce cavitation in sliding vane pumps, making embodiments particularly suitable for such pumps.

In some embodiments, the channel comprises 1 and 2mm ² Cross-section between.

The size of the channel required to inhibit cavitation will depend on the density of the fluid being pumped and the rotational speed of the pump. The size of the channels should be limited to avoid excessive drop in pumping efficiency, but should be sufficient to allow some pressure relief and to inhibit cavitation. In many cases, 1 and 2mm ² The cross-section between will provide the flow necessary to inhibit cavitation without unduly affecting the performance of the pump.

In some embodiments, the channel is sized such that the limit (optimal) pressure achievable by the pump is reduced by between 5% and 15%.

As previously mentioned, the channel will reduce the limit pressure achievable by the pump, but has the advantage of suppressing cavitation. It has been found that the channel dimensions are selected such that the limit pressure achievable by the pump is reduced by a limited amount to provide an effective reduction in cavitation while still providing a highly efficient pump.

In some embodiments, there may be multiple channels. In some embodiments, the channels may take the form of grooves in the end face of the blade.

In some embodiments, the channel forms a substantially straight path between the two pumping chambers, while in other embodiments, the channel may not be straight.

Having a single channel and forming it as a straight channel may have the advantage of being easy to manufacture. However, there may be embodiments in which two or more channels are provided and/or in which the channels form a more complex angled path.

In some embodiments, the pump includes a lubricant pump for driving the valve and supplying lubricant to the vacuum pump.

The oil pump for supplying lubricant to the vacuum pump may be mounted on the same shaft as the vacuum pump, and thus, their rotational speed is set by the rotational speed of the vacuum pump and may be very high. Furthermore, vacuum pumps are often used to pump corrosive chemicals, and because lubricants within these pumps may need to be resistant to these chemicals, these lubricants may have high densities. Thus, cavitation problems may occur in such pumps for vacuum pumps, and embodiments may provide a particularly effective solution to this.

In some embodiments, the largest portion of the blade comprises a circular cross section; and at least one further portion of the blade comprises a non-circular cross-section.

A second aspect provides a sliding vane pump comprising: a rotor rotatably mounted within the stator; the rotor includes at least one vane slidably mounted within a respective at least one cavity; the rotor, stator and at least one vane defining a plurality of variable volume pumping chambers for delivering fluid from a fluid inlet to a fluid outlet upon rotation of the rotor, the at least one vane separating adjacent pumping chambers; and the largest part of the blade has a circular cross section; at least one further portion of the blade has a non-circular cross-section.

The circular cross-section of the main part of the blade means that the corresponding part of the cavity in which the blade slides has a corresponding circular cross-section. This results in easier machining and robust components. However, a circular cross section means that axial rotation or twisting of the blade may occur. The head of the vane has a shape that needs to be maintained in alignment with the inner wall of the stator to provide an effective seal. Thus, maintaining alignment of the heads requires some means to inhibit rotation of the blades. This problem is solved by providing a portion of the blade with a non-circular cross-section that allows the rotation of the blade to be prevented. Most of the blades have a circular cross section, which allows for easier machining of both the blades and the cavities within the rotor into which the blades are inserted. Since inhibiting axial rotation of a portion of a blade will inhibit axial rotation of the entire blade, only a portion has a non-circular cross-section.

In some embodiments, the at least one further portion is at one end of the blade.

In some embodiments, a cross-section of an annular recess within the stator configured to receive the sliding vane includes a non-circular cross-section corresponding to the non-circular cross-section of the vane.

It may be advantageous that the non-circular portion is at one end of the vane and in some cases the non-circular portion is the portion of the vane that extends out of the rotor cavity when the rotor is in a position furthest from the inner wall of the stator. The stator inner wall is provided with an annular recess having a corresponding non-circular cross section and this maintains the blades in a certain alignment and inhibits axial rotation as the blades extend out of the rotor and into the stator.

In some embodiments, the at least one further portion is at both ends of the blade.

In the case of blades extending through the rotor, it may be advantageous for both ends of the blade to have a non-circular cross section, such that at any time at least one end of the blade will extend into the correspondingly shaped stator, and thus at any time at least one end of the blade, and thus the entire blade, is prevented from rotating.

In some embodiments, the at least one cavity within the rotor comprises a circular cross-section along a length of the cavity.

In the case of non-circular cross-section portions of the blades at both ends, then the end portions of the blades and the corresponding stator shape hinder axial rotation of the blades, and the cavities within the rotor may be circular along their entire length. This makes processing easier.

In other embodiments, a portion of the cavity within the rotor may have a non-circular cross-section, with the largest portion having a circular cross-section.

In some embodiments, the rotor includes an additional anti-rotation component mounted in a portion of the rotor cavity, the additional anti-rotation component configured to receive the at least one additional portion of the blade.

In some embodiments, the non-circular cross-sectional portion of the cavity may not be formed within the rotor itself, but may be formed by additional components, such as pins extending across the cavity. In some embodiments, the pin may be at one end of the cavity, the pin shielding a portion of the circular cross section and positioned such that it is within a portion of the cavity that accommodates the non-circular cross section portion of the vane and inhibits rotation of the sliding vane. This may be required if the blade does not extend through the rotor and has only one end with a non-circular cross section.

In some embodiments, the non-circular cross-section is smaller than the circular cross-section.

It may be advantageous that the non-circular cross section of the blade is smaller than the circular cross section, as this allows the blade to be machined from circular cross section portions. Furthermore, the blades may fit in a circular cross-section cavity within the rotor, with only a small portion of the cavity having a corresponding non-circular portion to prevent rotation. This allows for simple machining of the cavity and the addition of additional anti-rotation components such as pins to the machined cavity.

In some embodiments, the at least one additional portion comprises at least one recessed portion machined from an outer surface of the blade.

As previously described, in the case where the non-circular cross section is smaller than the circular cross section, the non-circular cross section may be machined from the outer surface to form the recessed portion.

In some embodiments, the at least one recessed portion comprises a flat axially extending surface.

The flat axially extending surface can be used to inhibit axial rotation and is easy to machine. In this regard, the respective flat surfaces of the recess or cavity into which the vane extends may be within the rotor, or in the event that the recess is located at one or both ends of the vane, then the respective shaped recess into which the end of the vane extends will be within the stator of the pump. This may be easier to machine than machining a shape in the cavity in the rotor.

A third aspect provides a vacuum pump comprising a sliding vane pump according to the first or second aspect for supplying lubricant to the vacuum pump.

A fourth aspect provides a vane for a sliding vane pump according to the first aspect, the vane being configured to be slidably mounted within and extend from a corresponding cavity in a rotor such that at least one end face of the vane abuts a stator inner wall and thereby separates adjacent pumping chambers when mounted in the rotor in the pump; the vane includes a channel configured to provide a passageway between the adjacent pumping chambers when the vane is installed within the pump.

In some embodiments, the channel comprises a groove in the at least one end face.

In other embodiments, the channel includes a passageway extending from a leading edge to a trailing edge of the blade when the blade is installed in the rotor.

A fifth aspect provides a vane for a sliding vane pump according to the second aspect, the vane being configured to have a substantially circular cross-section for a major portion of its length and a non-circular cross-section for a minor portion of its length, the vane being configured to be slidably mounted within and extend from a correspondingly shaped cavity in a rotor such that at least one end face of the vane abuts a stator inner wall and thereby separates adjacent pumping chambers when mounted in the rotor in the pump.

In some embodiments, the vane includes a channel configured to provide a passageway between the adjacent pumping chambers when the vane is installed within the pump.

In some embodiments, the at least one channel is located in at least one of the end faces.

Further specific and preferred aspects are set out in the attached independent and dependent claims. Features of the dependent claims may be combined with those of the independent claims as appropriate and combinations other than those explicitly set out in the claims.

Where a device feature is described as being operable to provide a function, it will be understood that this includes the device feature providing that function or being adapted or constructed to provide that function.

Drawings

Embodiments of the utility model will now be further described with reference to the accompanying drawings, in which:

FIG. 1 shows a section through a sliding vane pump according to an embodiment;

FIG. 2 shows an end view of a pump according to an embodiment;

FIG. 3 illustrates a stator or cylinder of a pump according to an embodiment;

FIG. 4 shows a sliding vane and a sliding vane mounted within a rotor;

FIG. 5 shows the cylinder of the pump mounted on the rotor;

FIG. 6 illustrates two blades according to various embodiments;

FIG. 7 shows a cross-sectional view through a pump according to one embodiment, with the rotor in different positions; and

fig. 8 schematically shows a sliding vane pump as an oil pump in a vacuum pump.

Detailed Description

Before discussing embodiments in more detail, an overview will first be provided.

Fig. 1 shows a section through a sliding vane pump. In this pump, the rotor 40 is mounted for eccentric rotation within the stator 50. The rotor 40 has sliding vanes 10 mounted therein, the sliding vanes 10 being configured to contact the inner wall of the stator 50 and slide within the rotor as the rotor rotates. Pumping chambers are formed between the sliding vane, the inner wall of the stator and the outer wall of the rotor. Rotation of the rotor pushes oil from the inlet 30 toward the outlet 20 as the rotor 40 rotates counter-clockwise.

Although in this embodiment only a single vane is shown extending across the diameter of the rotor, in other embodiments there may be two or more vanes mounted within correspondingly shaped recesses at different locations in the rotor, the vanes being biased to extend from their recesses and contact the stator inner wall. The blades, rotor and stator inner walls form pumping chambers.

In this embodiment there is an anti-rotation member in the form of a pin 41 which extends across a portion of the circular cross section at either end of the cavity in the rotor housing the blade. The blade 10 has recesses in portions at either end, otherwise circular in cross-section. These recesses slide against the pins such that the pins inhibit axial rotation of the blades. In other embodiments such as shown in fig. 3 and 4, the cross-sectional shape of the stator receiving the blade matches the non-circular shape of the blade end and this is sufficient to inhibit rotation of the blade without the need for additional non-rotating components such as pins 41. However, in embodiments where the blades do not extend through the stator (not shown), anti-rotation features within the rotor cavity itself or modifying the shape of the rotor cavity are required to inhibit rotation when the rotor is in a position where the blades do not extend out of the cavity (the position of the left hand side of the blades in this figure).

Fig. 2 shows an end view of the pump of fig. 1 and shows the exhaust pipe leading to the exhaust outlet 20 and the inlet tooling holes leading to the inlet 30. A pressure limiter 60 is also shown. In this embodiment, the sliding vane pump is a lubricant pump for supplying lubricant to the vacuum pump. The pressure limiter 60 controls the pressure of the lubricant supplied to the vacuum pump. In this embodiment, the rotor of the sliding vane pump is mounted on the same shaft as the vacuum pump rotor and thus rotates at the same high speed. The temperature of the pump will rise during operation and will affect the viscosity of the lubricant and the pressure of the lubricant supplied to the vacuum pump. The pressure limiter 60 is used to control the supply of lubricant to the vacuum pump.

Some components of the sliding vane pump are shown in figures 3 and 4. Fig. 3 shows a stator or cylinder of a pump 50, the stator having an annular recess or groove with a sealing surface 52 and an anti-rotation surface 53 configured to correspond to the truncated circular cross-sectional shape of the end portion of the vane shown in fig. 4. These corresponding non-circular shapes inhibit axial rotation of the blade. The main part of the blade has a circular cross-section corresponding to the cross-section of a cylindrical cavity extending through the rotor.

Fig. 4 shows a rotor 40 with sliding vanes 10. The sliding vane is shown separate from the rotor and mounted within the rotor. The left hand side blade has a circular cross section over most of its length with a recessed end portion that mates with a similarly shaped surface 52 in the stator 50 of fig. 3, thereby preventing the blade from rotating about its longitudinal axis. In the right hand side view there is a side portion protruding from the longitudinal side surface of the sliding vane and which further prevents the vane from twisting or rotating about its longitudinal axis when mounted in a correspondingly shaped cavity in the rotor.

Fig. 5 shows a pump cylinder or stator 50 mounted on the rotor. The figure also shows a shaft 42 on which the rotor is mounted.

Fig. 6 shows the end face 8 of the blade 10 in more detail. The upper left hand side of fig. 6 shows a vane of an embodiment of the second aspect, wherein the end face 8 forms a sealing surface for sealing against the inner wall 52 of the stator to isolate the pumping chambers from each other. The sealing surface is curved to correspond to a curved inner wall 52 of the pump cylinder or stator 50 (see fig. 3). In the side facing the end there is a recess which makes the cross section non-circular. This corresponds to the non-circular cross-sections of the pump cylinders in the stator, and these corresponding non-circular cross-sections prevent the blades 12 from rotating about their longitudinal axes.

The upper right hand side of the figure shows a similar embodiment in which there is a channel 12 in the end face 8 of the vane 10 which provides a passageway between adjacent pumping chambers separated by the vane and which allows fluid to flow from a lower pressure region on one side of the vane to a higher pressure region on the other side of the vane which inhibits the formation of bubbles in the lower pressure region. The channel 12 is arranged such that it provides a path between the leading and trailing edges of the vanes in operation of the pump, and provides a bypass path between adjacent pumping chambers. It should be noted that forming the channels 12 on the end faces of the blades is easy to manufacture, inexpensive and robust. An alternative may be to have a passageway with a cylindrical form extending through a portion of the vane extending from a recess or cavity in the rotor in substantially all positions of the rotor. Alternatively, the channels 12 may be formed as grooves on the inner wall of the stator rather than grooves on the sliding vane itself.

The lower diagram in fig. 6 shows example dimensions for this particular embodiment. In this example, the channel in the form of a groove has a width of 1mm and a depth of 1.4 mm. The total width of the blade was 4.9mm and the length of the blade was 40mm. In this embodiment, the length of the vane corresponds to the distance between the opposing surfaces 52 of the pump cylinder 50 through which the vane extends.

Fig. 7 shows a section through the pump with the rotor in different positions. The arrow shows the counter-clockwise direction of rotation of the rotor. Arrow 72 points to the compression chamber, i.e. the pumping chamber, as follows: rotation of the rotor at this location reduces the size of the pumping chamber, pushing oil out of the chamber towards and through the outlet 20. The chamber 74 is a lower pressure chamber in which the pumping chamber expands and oil is drawn into the expanded pumping chamber 74 from the inlet 30. Region 70 is where cavitation is likely to occur because it is the lower pressure region in the expansion chamber. The passage formed by the grooves 12 in the vane end faces between adjacent pumping chambers provides a flow path for fluid from the higher pressure region 72 to the lower pressure region 70 where cavitation may occur. This increases the pressure in the lower pressure region and inhibits cavitation. As can be appreciated, this does result in a slightly less efficient pump, and the dimensions of the channels are selected such that cavitation is suppressed, but the efficiency of the pump is still maintained at a desired level. The level may be set such that the limit pressure that the pump can produce is reduced by only 15%, preferably by less than 10%. In this regard, the pressure generated by the oil pump may be higher than is normally required in some embodiments, and may be controlled by a pressure limiter as shown in fig. 2, in which case it may be unacceptable to reduce the limit pressure available by the pump.

Fig. 8 shows an embodiment in which an oil pump 80 is mounted to provide lubrication to and drive the valves of a vacuum pump 90. It can be seen that the oil pump is mounted on the shaft 42 of the vacuum pump driven by the motor 95. The rotational speed of the rotor of the oil pump is set by the requirements of the vacuum pump. Thus, the rotor can rotate at very high rotational speeds, typically on the order of 1500 to 1800 rpm. Furthermore, in the case where a vacuum pump is used to evacuate chemically aggressive products, as may occur in semiconductor processing, the oil or lubricant supplied by pump 80 is selected to be a chemically resistant lubricant. The lubricant may have a high density, one such lubricant having a density of 1.88kg per liter. This is more than twice the density of normal mineral oil, and the combination of high pumping speed and high density of the fluid being pumped increases the chance of cavitation that may cause knocking within the pump. Providing channels that allow flow of a restricted fluid between adjacent pumping chambers inhibits cavitation and may improve pump performance.

Although in the illustrated embodiment there is a single vane extending through the rotor, it should be understood that in other embodiments the vane may be formed as two separate vanes extending from opposite sides of the rotor and spring biased against the stator inner wall. Other embodiments with more pumping chambers and more vanes are also contemplated and may benefit from a restricted pressure relief channel between adjacent pumping chambers.

Embodiments also provide a method of upgrading a pump in which the vanes are replaced with vanes having grooves or passages, allowing conventional pumps to operate at higher speeds and with higher density lubricants while still inhibiting cavitation.

Embodiments also provide a method of servicing a sliding vane pump, wherein worn vanes are replaced with vanes having grooves or passages.

Although illustrative embodiments of the present utility model have been disclosed in detail herein with reference to the accompanying drawings, it is to be understood that the utility model is not limited to the precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope of the utility model as defined by the appended claims and their equivalents.

Reference numerals

8. End face of blade

10. Blade

12. Channel

20. An outlet

30. An inlet

40. Rotor

41. Pin

42. Shaft

50. Stator or pump cylinder

52. Annular recess sealing surface in stator

53. Anti-rotation surface

60. Pressure limiter

70. Potential cavitation sites behind blade heads

72. Compression pumping chamber

74. Reduced pressure pumping chamber

80. Oil pump

90. Vacuum pump

95. Motor with a motor housing

Claims

1. A sliding vane pump, said pump comprising:

a rotor rotatably mounted within the stator;

the rotor includes at least one vane slidably mounted within a respective at least one cavity, at least one end face of the vane configured to abut an inner wall of the stator;

the rotor, stator and at least one vane defining a plurality of variable volume pumping chambers for delivering fluid from a fluid inlet to a fluid outlet upon rotation of the rotor, the at least one vane separating adjacent pumping chambers; and

a channel configured to provide a passageway between the adjacent pumping chambers;

wherein a cross-section of at least a portion of the length of the sliding vane includes a protruding portion configured to mate with a correspondingly shaped recess in the cavity in the rotor, the protruding portion inhibiting the vane from twisting about its longitudinal axis.

2. The sliding vane pump of claim 1, wherein said channel is formed in said at least one vane.

3. The sliding vane pump of claim 2, wherein said channel comprises a groove in an end face of said vane, at least a portion of said end face abutting said stator inner wall.

4. The sliding vane pump of claim 2, wherein said channel comprises a passageway in said vane.

5. The sliding vane pump of any of claims 1-4, wherein the at least one end face is curved to correspond to the stator inner wall and provide a sealing surface with the stator inner wall.

6. The sliding vane pump of any of claims 1-4, wherein the channel comprises a groove in the stator inner wall.

7. The sliding vane pump of any of claims 1-4, comprising a single vane slidably mounted in a cavity extending through the rotor, either end of the vane abutting the inner wall of the stator.

8. The sliding vane pump of claim 7, wherein said channel comprises a groove in an end face of said vane, at least a portion of said end face abutting said stator inner wall, wherein both end faces of said vane comprise said groove.

9. The sliding vane pump of any of claims 1-4, wherein the rotor is mounted for eccentric rotation within the stator.

10. The sliding vane pump of any of claims 1-4, wherein the pump is configured to pump lubricant.

11. The sliding vane pump of claim 10, wherein the pump is configured to pump a high density lubricant having a density of greater than 1.5 kg/liter.

12. The sliding vane pump of any of claims 1-4, wherein the channel is comprised at 1mm ² And 2mm ² Cross-section between.

13. The sliding vane pump of any of claims 1-4, wherein the channel is sized such that the pump is capable of achieving a 5% and 15% reduction in ultimate pressure.

14. The sliding vane pump of any of claims 1-4, wherein the largest portion of the vane comprises a circular cross-section; and

at least one further portion of the blade comprises a non-circular cross-section.

15. A sliding vane pump, characterized in that it comprises a rotor rotatably mounted within a stator;

the rotor includes at least one vane slidably mounted within a respective at least one cavity;

the largest part of the blade has a circular cross section;

at least one further portion of the blade has a non-circular cross-section.

16. The sliding vane pump of claim 15, wherein said at least one further portion is at one end of said vane.

17. The sliding vane pump of claim 16, wherein said at least one further portion is at both ends of said vane.

18. The sliding vane pump of any of claims 15-17, wherein a cross-section of a recess within the stator configured to receive the sliding vane comprises a non-circular cross-section corresponding to the non-circular cross-section of the vane.

19. A sliding vane pump according to any one of claims 15 to 17, wherein the at least one cavity within the rotor comprises a circular cross-section along the length of the cavity.

20. A sliding vane pump according to any one of claims 15 to 17, wherein the rotor comprises an additional anti-rotation component mounted in a portion of the rotor cavity, the additional anti-rotation component being configured to receive the at least one further portion of the vane.

21. A sliding vane pump according to any one of claims 15 to 17, wherein the non-circular cross-section is smaller than the circular cross-section.

22. A sliding vane pump according to any one of claims 15 to 17, characterized in that the at least one further portion comprises at least one recess machined from the outer surface of the vane.

23. The sliding vane pump of claim 22, wherein said at least one recess portion comprises a flat axially extending surface.

24. A sliding vane pump according to any one of claims 15 to 17, characterized in that the pump comprises a lubricant pump for driving the valve and supplying lubricant to the vacuum pump.

25. A vacuum pump, characterized in that it comprises a sliding vane pump according to any one of claims 1-24 for supplying lubricant to the vacuum pump.

26. A vane for a sliding vane pump according to any one of claims 1 to 14, the vane being configured to be slidably mounted within and extend from a respective cavity in a rotor such that at least one end face of the vane abuts a stator inner wall and thereby separates adjacent pumping chambers when mounted in the rotor in the pump;

the vane includes a channel configured to provide a passageway between the adjacent pumping chambers when the vane is installed within the pump.

27. The blade of claim 26 wherein the channel comprises a groove in the at least one end face of the blade.

28. The blade of claim 27 wherein the channel comprises a passageway extending through the blade.

29. A vane for a sliding vane pump according to any one of claims 15 to 24, characterized in that the vane is configured to have a substantially circular cross section for a larger part of its length and a non-circular cross section for a smaller part of its length, the vane being configured to be slidably mounted in and extend from a correspondingly shaped cavity in a rotor such that at least one end face of the vane abuts a stator inner wall and thereby separates adjacent pumping chambers when mounted in the rotor in a pump.