Pump

Abstract

A pump has a housing in which a rotor is arranged, which is rotatable in the housing about a housing-fixed axis of rotation, the rotor having at least one recess in which is received at least one displacement body which, when the rotor rotates, revolves about the axis of rotation and at the same time runs along on a housing inner wall of the housing, the displacement body being radially movable in the recess between a position retracted into the recess and a position extended out of the recess. A first chamber is present between the outside of the rotor and the housing inner wall. The displacement body, when it revolves about the axis of rotation, subdivides the first chamber into a leading first subchamber and a trailing second subchamber. The first subchamber is connected by means of a first duct and the second subchamber by means of a second duct in the rotor to a further chamber which is formed between the displacement body and an inner wall of the recess and which, according to the radial movements of the displacement body which occur when the rotor revolves about the axis of rotation, is alternately increased in volume, with the result that an additional vacuum arises in the further chamber and in the second subchamber, or decreased in volume, with the result that an additional overpressure arises in the further chamber and in the first subchamber.

Description

BACKGROUND OF THE INVENTION

The invention generally relates to pumps, in particular to rotary-slide pumps.

More specifically, the invention relates to a pump, comprising a housing in which a rotor is arranged, which is rotatable in the housing about a housing-fixed axis of rotation, the rotor having at least one recess in which is received at least one displacement body which, when the rotor rotates, revolves around the axis of rotation and at the same time runs along on a housing inner wall of the housing, the displacement body being movable radially in the recess between a position retracted into the recess and a position extended out of the recess, the housing inner wall having, as seen in the circumferential direction about the axis of rotation, a region in which the housing inner wall is spaced apart from an outside of the rotor, so that a first chamber is present in this region between the outside of the rotor and the housing inner wall, the displacement body, when it revolves around the axis of rotation, subdividing the first chamber into a leading first subchamber and a trailing second subchamber.

A rotary-slide pump has a usually hollow-cylindrical housing in which is arranged a rotor which is likewise usually in the form of a cylinder. The axis of rotation of the rotor is in this case arranged eccentrically in the housing, so that the housing inner wall is spaced apart from the outside of the rotor in a circumferential region of the rotor. The rotor touches the housing inner wall between an inlet port and outlet port in the housing. The touching point forms the separating point between the suction space and delivery space inside the housing. In conventional rotary-slide pumps, one or more, mostly radially arranged recesses are incorporated in the rotor. One or more displacement bodies designed in the form of rotary slides is or are seated in the recess or recesses. The rotary slides subdivide the chamber between the outside of the rotor and the housing inner wall into a plurality of subchambers. The rotary slides are received radially movably in the recesses. They are often pressed against the housing inner wall by a spring attached in the bottom of the recess.

In conventional rotary-slide pumps, when the rotor rotates the only radially movable displacement bodies designed as rotary slides run by sliding with their radially outer end along the housing inner wall, this adversely entailing high friction particularly at high rotation speeds and correspondingly high centrifugal forces.

A further disadvantage of conventional rotary-slide pumps is that only the chamber between the outside of the rotor and the housing inner wall is used as a suction and pumping space, thus limiting the pumping capacity of conventional rotary-slide pumps.

When conventional rotary-slide pumps are used as vacuum pumps, correspondingly, only a high vacuum range of 1.0 to 0.001 bar can be generated by them. When a conventional rotary-slide pump is used as a high-pressure pump, the pressure which can correspondingly be achieved is likewise limited.

SUMMARY OF THE INVENTION

The object on which the invention is based is to design a pump of the type mentioned in the introduction, to the effect that higher pumping capacities can be achieved by means of the pump, whether as a vacuum pump or high-pressure pump or as a feed pump for gaseous and/or liquid media.

According to the invention, a pump is provided, comprising

a housing having a housing inner wall,

a rotor arranged in the housing, the rotor having at least one recess, the rotor being rotatable in the housing about a housing-fixed axis of rotation,

at least one displacement body received in the at least one recess of the rotor, the displacement body, when the rotor rotates about the housing-fixed axis of rotation, revolves about the axis of rotation and at the same time runs along on the housing inner wall of the housing, the displacement body being radially movable in the recess between a position retracted into the recess and a position extended out of the recess,

a first chamber arranged between the housing inner wall and an outside of the rotor,

a leading first subchamber and a trailing second subchamber, into which the displacement body, when revolving about the axis of rotation, subdivides the first chamber,

a further chamber formed between the displacement body and an inner wall of

the recess,

a first duct connecting the leading first subchamber with the further chamber, a second duct connecting the trailing second subchamber with the further chamber,

the further chamber, according to the radial movements of the displacement body which occur when the rotor revolves about the axis of rotation, is alternately increased in volume, with the result that an additional vacuum arises in the further chamber and in the second subchamber, and decreased in volume, with the result that an additional overpressure arises in the further chamber and in the first subchamber.

In the pump according to the invention, the achievable pumping capacity is increased in that not only is the first chamber between the outside of the rotor and the housing inner wall used as a suction and delivery space, but a further chamber is present on that side of the displacement body which faces away from the housing inner wall, between the said displacement body and the inner wall of the recess, and is likewise used as a suction delivery space, with the result that the overall volume of the suction delivery space of the pump according to the invention is increased, as compared with conventional rotary-slide pumps. When the displacement body moves out of its position retracted into the recess into the position extended out of the recess, a vacuum or suction arises in the further chamber, and, when the displacement body moves out of the extended position back into the retracted position again, overpressure arises in the further chamber. The further chamber thus acts, in the suction phase, as an additional suction space and, in the delivery phase, as an additional delivery space. The further chamber is connected in each case via at least one duct in the rotor to the first subchamber and to the second subchamber, so that corresponding pressure equalization takes place between the two subchambers and the further chamber, depending on the suction or the delivery phase. The first duct and/or the second duct may in this case be designed as bores in the rotor, if the latter is in the form of a solid body, or else as lines inside the rotor if the latter is hollow.

The pump according to the invention may be used for generating a vacuum, for generating high pressure, as a hydraulic pump, as a feed pump for gaseous and/or liquid media, etc.

In a preferred refinement, the displacement body has, on its side facing the inner wall of the recess, a surface contour which corresponds to the inner contour of the inner wall of this recess.

The advantage of this measure is that, when the displacement body is retracted completely into the recess, the further chamber has a vanishingly small volume, as a result of which, in the suction phase, an especially high suction pressure can be generated and, in the delivery phase, the medium located in the further chamber can be displaced completely out of the further chamber, with the result that especially high pressures can be achieved.

In a further preferred refinement, the housing inner wall, along which the displacement body runs, has a surface contour which corresponds to the surface contour of that side of the displacement body which faces the housing inner wall.

It is in this case advantageous that, simply by the surface contour of the displacement body and the housing inner wall of the displacement body being adapted to one another, a sufficient sealing action for sealing off the first subchamber from the second subchamber is brought about without any further sealing measures.

In a further preferred refinement, the displacement body is designed as a body of revolution which can rotate in the recess at least about an axis parallel to the axis of rotation.

This measure, which is also considered as an independent invention without the features of the characterizing clause, has the advantage that the friction between the displacement body on the housing inner wall, when the displacement body runs along the latter, is greatly reduced because the displacement body can roll on the housing inner wall. At high rotational speeds of the rotor and correspondingly high rolling speeds of the body of revolution, a film of the medium (gas or liquid) occurs between the body of revolution in the housing inner wall and further reduces the friction. In this refinement, the high frictional forces occurring in conventional rotary-slide pumps, particularly at high rotational speeds of the rotor, are advantageously reduced to a minimum, with the result that the pump according to the invention has substantially lower wear than conventional rotary-slide pumps and requires less energy for driving it.

In connection with the abovementioned refinement, it is preferable if the displacement body is a ball.

The advantage of having a ball as displacement body is that the ball can rotate in the recess about any body-specific axes, as a result of which it is possible for the displacement body to roll on the housing inner wall even when the axis of rotation of the rotor is not exactly parallel to the housing mid-axis because of tolerances.

In this case, it is preferable, furthermore, if the ball is a hollow ball.

It is advantageous in this case that the displacement body has a lower mass, thus, on the one hand, reducing the centrifugal forces active on the displacement body when the rotor rotates and, moreover, reducing the drive energy required for operating the pump.

If the displacement body is a ball, it is preferable, furthermore, if the inner wall of the recess is in the form of a part-spherical surface area.

In this refinement, the displacement body designed as a ball can reduce the volume of a further chamber virtually to zero in the position in which it is retracted to a maximum into the recess and in which the ball bears completely against the inner wall of the recess, as a result of which an especially high pressure is achieved in the delivery phase and an especially high suction action is achieved in the suction phase.

Alternatively to the configuration of the displacement body as a ball, however, it is likewise preferable if the displacement body is a cylinder, the cylinder axis of which runs parallel to the axis of rotation.

In this case, too, the displacement body is designed as a body of revolution, the cylinder, when it runs along on the housing inner wall, rolling on the latter due to rotation about the cylinder axis, as a result of which, in turn, friction is greatly reduced. As compared with a ball as displacement body, a cylinder has the further advantage that the further chamber and also the first chamber can be made larger by the cylinder being configured to be correspondingly long in the direction of the cylinder axis, in order to achieve even higher pumping capacities.

Whereas when the displacement body is configured as a ball, the rotor has a spherical basic shape, when the displacement body is configured as a cylinder the rotor has a cylindrical basic shape, the further advantage of this being that the rotor can be joined together axially in the direction of the cylinder axis from two or more sections by screwing, thus also making it simpler to introduce the at least one first and the at least one second duct.

In the displacement body configured as a cylinder, too, the latter is in turn preferably designed as a hollow cylinder, and, according to a further preferred refinement, the inner wall of the recess is in the form of a part-cylindrical surface area.

In a further preferred refinement, a first valve is arranged in the first duct and closes the first duct when the displacement body moves out of the retracted position into the extended position, and releases the first duct when the displacement body moves out of the extended position into the retracted position.

The first valve serves for controlling pressure equalization between the further chamber and the first subchamber which, when the displacement body is revolving, forms the delivery space. When the displacement body moves out of the retracted position, with the result that a suction action occurs in the further chamber, the first valve, which is then in its closing position, prevents the first subchamber (delivery space) from communicating with the further chamber. Conversely, the first chamber releases the first duct when the displacement body moves out of the extended position into the retracted position, as a result of which, in the delivery phase which then takes place, the further chamber communicates with the first subchamber in order to increase the pressure additionally in the first subchamber.

Comparably, preferably a second valve is arranged in the second duct and releases the second duct when the displacement body moves out of the retracted position into the extended position, and closes the second duct when the displacement body moves out of the extended position into the retracted position.

The function of the second valve is essentially converse to the function of the first valve and advantageously controls communication between the further chamber and the second subchamber (suction chamber) in the suction phase, in which the further chamber communicates with the second subchamber for generating an additional suction action, and, in the delivery phase, the second valve interrupts communication between the further chamber and the second subchamber.

Furthermore, it is preferable if the first valve and/or the second valve are/is controlled automatically by the instantaneous pressures prevailing in the first and/or the second duct on both sides of the first valve and/or on both sides of the second valve.

The advantage of this measure is that measures for active control, for example for an electromotive control of the valves, may be dispensed with, and therefore the production costs of the pump and also the outlay in terms of maintenance on the pump are reduced. Advantageously, the pressure in the first and/or second duct, which varies when the displacement body revolves around the axis of rotation, is utilized in order to control the opening and closing of the first valve and/or of the second valve. In the suction phase, in which the displacement body moves out of the retracted position to the extended position, the second valve is opened automatically, while, conversely, when the displacement body moves from the extended position into the retracted position in the recess, the first valve is opened automatically and the second valve is closed automatically.

In a further preferred refinement, the first valve has a first valve disc and a first valve seat, the first valve disc closing against the first valve seat in the direction towards the first subchamber, the first valve disc preferably being prestressed into its closing position.

Correspondingly, the second valve preferably has a second valve disc and a second valve seat, the second valve disc closing against the first valve disc in the direction towards the second subchamber, the second valve disc preferably being prestressed into its closing position.

The configuration of the first and/or second valve in a type of construction with the valve disc and valve seat is very simple in structural terms, and the prestressing of the first and/or second valve disc into the closing position makes it possible advantageously and simply to control the opening and closing of the first and/or second valve by means of the instantaneous pressure prevailing in the first and/or the second duct, as described above.

In the abovementioned refinement, the first and the second valve are arranged in relation to one another such that their opening and closing movements are contradirectional to one another, this being advantageous particularly in a passive control of the valves by means of the prevailing instantaneous pressure.

In a further preferred refinement, the first valve is arranged in the first duct such that the first valve disc and the first valve seat are oriented essentially in the circumferential direction about the axis of rotation, and/or the second valve is arranged in the second duct such that the second valve disc and the second valve seat are oriented essentially in the circumferential direction about the axis of rotation.

This measure has the advantage that the mass inertia forces arising during the rotation of the rotor and acting on the two valves in the circumferential direction about the axis of rotation additionally assist the control of the two valves by means of the instantaneous pressure prevailing in the first and/or the second duct. Thus, for example, in the suction phase of the pump, these forces bring about a reliable closing of the first valve in the first duct (delivery duct).

In a further preferred refinement, a plurality of first ducts and a plurality of second ducts are present in the rotor.

This refinement is advantageous particularly in conjunction with the configuration of the displacement body as a cylinder, because, depending on the selected length of the cylinder, the provision of a plurality of first and second ducts affords a sufficient pressure equalization cross section between the first subchamber or the second subchamber and the further chamber.

A pump according to the invention, in contrast to conventional rotary-slide pumps, requires only one displacement body, even when the rotor of the pump according to the invention can be configured such that a plurality of displacement bodies are present there in a plurality of recesses.

Furthermore, it is possible, within the scope of the invention, to arrange, for equalizing the masses, preferably two to four pumps according to the invention on a common axis as a unit, in which the rotors are arranged so as to be offset radially with respect to one another at 180°. As a result, in particular, a continuous suction and delivery action of the overall pump arrangement can also be achieved.

Further advantages and features may be gathered from the description and the accompanying drawing.

It will be appreciated that the features mentioned above and those yet to be explained below can be used not only in the combination specified in each case, but also in other combinations or alone, without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are illustrated in the drawing and are described in more detail hereafter with reference to this. In the drawing:

FIG. 1 shows a pump in a partially cutaway perspective illustration;

FIG. 2 a) and b) show the pump in FIG. 1 in a first operating position, FIG. 2a) showing a section along the line A-A in FIG. 2b) and FIG. 2b) showing a section along the line B-B in FIG. 2a);

FIG. 3 a) and b) show the pump in FIG. 1 in a further operating position, FIG. 3a) showing a section along the line A-A in FIG. 3b) and FIG. 3b) showing a section along the line B-B in FIG. 3a);

FIG. 4 a) and b) show the pump in a further operating position, FIG. 4a) showing a section along the line A-A in FIG. 4b) and FIG. 4b) showing a section along the line B-B in FIG. 4a);

FIG. 5 a) and b) show the pump in yet a further operating position, FIG. 5a) showing a section along the line A-A in FIG. 5b) and FIG. 5b) showing a section along the line B-B in FIG. 5a);

FIG. 6 shows a further exemplary embodiment of a pump in a partially cutaway perspective illustration;

FIG. 7 a) and b) show a first operating position of the pump in FIG. 6, FIG. 7a) showing a section along the line A-A in FIG. 7b) and FIG. 7b) showing a section along the line B-B in FIG. 7a); and

FIG. 8 a) and b) show a further operating position of the pump in FIG. 6, FIG. 8a) showing a section along the line A-A in FIG. 8b) and FIG. 8b) showing a section along the line B-B in FIG. 8a).

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

FIG. 1 illustrates a pump given the general reference symbol 10. The pump 10 may be used as a vacuum pump, as a high-pressure pump, as a feed pump for gaseous and/or liquid media, etc.

FIG. 2 a) to FIG. 5b) illustrate details of the pump 10 and various operating positions of the pump 10.

The pump 10 has a housing 12 which has essentially a spherical form in the exemplary embodiment shown.

The housing 12 is constructed from two housing parts 14 and 16 (see FIG. 2a)) which are fastened to one another along flanges 18 and 20, for example by means of screws (not illustrated).

The housing 12 has an inlet 22, through which the medium can be admitted into the housing 12, and an outlet 24, through which the medium is discharged again.

A rotor 26 is arranged in the housing 12. The rotor 26 is mounted in the housing 12 rotatably about an axis of rotation 28 in the direction of an arrow 30 in FIG. 2a) or of an arrow 32 in FIG. 2b). For this purpose, the rotor 26 has in the direction of the axis of rotation 28 axial extensions 34 and 36 which are mounted rotatably in the housing 12 by means of bearings 38, 40. The axial extension 36 has a further extension 42 which projects out of the housing 12 and which serves as a drive shaft for the rotor 26.

The housing-fixed axis of rotation 28 is arranged in the housing 12 eccentrically with respect to the housing centre, as can be gathered from FIG. 2a). As a result, a housing inner wall 44 has between a point 46 and a point 48 a region in which the housing inner wall 44 is spaced apart from an outside 50 of the rotor 26. At the points 46 and 48 of the housing inner wall 44, only a small gap with the outside 50 of the rotor 26 is present, but the medium (gas or liquid) can pass through this gap.

Thus, between the outside 50 and the rotor 26 in the housing inner wall 44, in the region between the points 46 and 48, as seen in the direction of rotation according to the arrow 30 about the axis of rotation 28, a first chamber 52 is present which is flooded completely by the medium admitted through the inlet 22, as is also described below.

The outside 50 of the rotor 26 corresponds essentially to the surface of a sphere.

The rotor 26 has a recess 54 in which at least one displacement body 56, exactly one in the exemplary embodiment shown, is received.

In the exemplary embodiment shown, the displacement body 56 is designed as a ball 58. The ball 58 is a hollow ball. The ball 58 is received in the recess 54 rotatably about any axes of the ball.

Furthermore, the ball 58 is arranged in the recess 54 so as to be radially movable with respect to the axis of rotation 28. When the rotor 26 rotates about the axis of rotation 28, the ball 58 always runs along on the housing inner wall 44 of the housing 12, the centrifugal forces which act on the ball 58 during the rotation of the rotor 26 having the effect that the ball 58 always bears against the housing inner wall 44.

The ball 58 is movable in the recess 54 between a radially retracted position, shown in FIG. 2a) and b), and a maximum extended position, illustrated in FIG. 4a) and b). The extent of the recess 54 in the direction perpendicular to the axis of rotation 28 is selected, according to FIG. 4a) and b), such that, in the maximum extended position, the ball 58 is still received with at least half its diameter in the recess 54 of the rotor 26.

The recess 54 in the rotor 26 is designed such that an inner wall 60, facing the ball 58, of the recess 54 corresponds to the surface contour of the ball 58, that is to say the inner wall 60 is in the form of a part-spherical surface area. In the position when the ball 58 is retracted completely into the recess 54 according to FIG. 2a) and b), the ball 58 bears completely over half its ball circumference against the inner wall 60 of the recess 54.

The housing inner wall 44 of the housing 12, along which wall the ball 58 runs when it revolves around the axis of rotation 28, has a surface contour which is likewise adapted to the surface contour of the ball 58 which is therefore designed here, in the section according to FIG. 2b), to be part-circular, in particular semicircular.

When the ball 58 revolves around the axis of rotation 28, the ball 58 subdivides the first chamber 52 into a leading first subchamber 62 and a trailing second subchamber 64. The first subchamber 62 forms a delivery space and the second subchamber 64 forms a suction space. When the ball 58 revolves along the housing inner wall 44, the first subchamber 62 and the second subchamber 64 vary correspondingly in relation to one another with regard to their volumes.

A further chamber 66 is formed between the ball 58 and the inner wall 60 of the recess 54 of the rotor 26 and, when the ball 58 revolves around the axis of rotation 28, is periodically increased and decreased in volume on account of the radial movement of the ball 58 between its position retracted into the recess 54 and its position extended out of the recess 54. The ball 58 always seals off the further chamber 66 with respect to the first and the second subchamber 62, 64, that is to say independently of its radial position in the recess 54.

In the rotor 26, a first duct 68 is present, which connects the first subchamber 62 to the further chamber 66, and a second duct 70 is present, which connects the second subchamber 64 to the further chamber 66. The further chamber 66 can thus communicate with the first subchamber 62 and with the second subchamber 64 in a pressure-equalizing manner, communication of the further chamber 66 with the first subchamber 62 and with the second subchamber 64 taking place essentially alternately when the ball 58 revolves around the axis of rotation 28.

The first duct 68 and the second duct 70 issue into the further chamber 66 via a common section 71. In the exemplary embodiment shown, the first duct 68 and the second duct 70 are designed as bores in the rotor 26. The first duct 68 and the second duct 70 issue into the first subchamber 62 and into the second subchamber 64 in the immediate vicinity of the orifice of the recess 54.

A first valve 72 is arranged in the first duct 68 and a second valve 74 is arranged in the second duct 70. The first valve 72 closes the first duct 68, so that, in this state, the first subchamber 62 does not communicate with the further chamber 66 when the ball 58 moves out of the retracted position into the extended position. The first valve 72 releases the first duct 68 when the ball 58 moves out of the extended position into the retracted position, so that, in the open position of the first valve 72, the first subchamber 62 communicates with the further chamber 66, with the result that the same pressure prevails in the first subchamber 62 and in the further chamber 66. The second valve 74 releases the second duct 70 when the ball 58 moves out of the radially retracted position into the radially extended position, so that the same pressure prevails in the second subchamber 64 and in the further chamber 66, and closes the second duct 70 when the ball 58 moves out of the extended position into the retracted position.

The first valve 72 and the second valve 74 are in this case controlled automatically by the instantaneous pressures prevailing in the first duct 68 and the second duct 70 on both sides of the first and the second valve 72 and 74.

The first valve 72 has a first valve disc 76 which cooperates with the first valve seat 78, and, in the closing position of the first valve 72, the first valve disc 76 closes against the first valve seat 78 in the direction towards the first subchamber 62.

The second valve 74 has a second valve disc 80 which cooperates with a second valve seat 82, and, in the closing position of the second valve 74, the second valve disc 80 closes against the second valve seat 82 in the direction towards the second subchamber 64.

Both the first valve 72 and the second valve 74 are prestressed into their closing position by means of a spring 84 and 86. The prestressing of the valves 72, 74 is likewise a parameter for controlling the valves 72, 74 in addition to the abovementioned instantaneous pressures in the ducts 68, 70.

The valves 72 and 74 are arranged in the first duct 68 and in a second duct 70 such that the first valve disc 76 and first valve seat 78 and the second valve disc 80 and second valve seat 82 are oriented in the circumferential direction about the axis of rotation 28.

The pump 10 has a seal 88 which is arranged in a middle web 90 of the housing 12, the said middle web separating the inlet 22 from the outlet 24. According to FIG. 2b), the seal 88 is designed to be approximately semicircular in the plane of the axis of rotation 28 and is prestressed radially elastically against the rotor 26 by means of a corrugated spring 92, so that the seal 88 bears against the rotor 26.

The pump 10 does not require any further seals.

The operation of the pump 10 is described in more detail below.

In the operating position shown in FIG. 2a) and b), the rotor 26 is in the rotary position, designated here as 0° position, with respect to the axial rotation 28. In this position, the ball 58 is retracted into the recess 54 to the maximum, so that the volume of the further chamber 66 is minimal or even zero. In this position, the ball 58 is approximately level with the middle web 90 between the inlet 22 and the outlet 24.

The same pressure prevails in the first duct 68, in the second duct 70 and in the first chamber 52 which, in this rotary position of the rotor 26, is not yet subdivided into the first subchamber 62 and the second subchamber 64. The first valve 72 and second valve 74 are both closed because no opening force acts on either of the two valves 72, 74.

FIG. 3 a) and b) shows the pump 10 in an operating position in which the rotor 26 has been rotated about the axial rotation 28 at somewhat less than 90° with respect to the 0° position in FIG. 2a) and b). The ball 58, while continuously running along on the housing inner wall 44, has in this case moved radially out of the recess 54 somewhat, with the result that the volume of the further chamber 66 has increased. The increase in volume of the further chamber 66 gives rise in the further chamber 66 to an additional vacuum which has the effect of opening the second valve 74. This gives rise at the inlet 22 to an additional suction action, as a result of which medium flows through the inlet 22 and through the second duct 70 into the further chamber 66, as indicated by arrows 94, 96. Approximately in this orbital position about the axis of rotation 28, the ball 58 commences to subdivide the first chamber 52 into the first subchamber 62 and the second subchamber 64. This gives rise in the first chamber 52 to a delivery space (first subchamber 62) and a suction space (second subchamber 64). The ball 58 bearing against the housing inner wall 44, the two subchambers 62, 64 are sealed off with respect to one another.

The first valve 72 is still closed. Since the first valve disc 76 closes against the first valve seat 78 opposite to the direction of rotation in the rotor 26 about the axis of rotation 28, the first valve disc 76 is still pressed against the first valve seat 78 by mass inertia and under the action of the spring 84, so that the suction pressure or vacuum arising in the further chamber 66 does not open the first valve 72. The converse is the case with regard to the second valve 74, the second valve disc 80 of which closes against the second valve seat 82 in the direction of rotation, so that, on account of the rotation movements of the rotor 26 about the axis of rotation 28, the mass inertia lifts off the second valve disc 80 from the second valve seat 82 counter to the action of the spring 86, in cooperation with the vacuum in the further chamber 66, with the result that the second valve 74 is opened.

In the position of the ball 58 or rotor 26 as shown in FIG. 3a) and b), an appreciable pressure has still not built up in the first subchamber 62, while the suction action in the second subchamber 64 which is formed is high.

In the illustration in FIG. 4a) and b), the rotor 26 has been rotated through 180° about the axis of rotation 28, starting from FIG. 2a) and b). In this position, the ball 58 is extended radially out of the recess 54 to the maximum. The volume of the further chamber 66 is then maximum and corresponds approximately to half the volume of the ball 58. The second valve 74 is still in its open position, while the first valve 72 is still closed. The further chamber 66 is then filled completely with the medium sucked in through the inlet 22. The medium sucked in continually through the inlet 22 passes through the slight gap between the outside of the rotor 26 and the housing inner wall 44, in the region of the point 46, into the second subchamber 64 and flows via the second duct 70 into the further chamber 66. The same pressure therefore prevails in the further chamber 66 as in the second subchamber 64.

In this rotary position of the rotor 26, the first subchamber 62 and the second subchamber 64 possess approximately the same volume.

Starting from FIG. 4a) and b), in FIG. 5a) and b) the rotor 26 has been rotated, for example, by somewhat more than 90° further on about the axis of rotation 28 (an approximately 270° position), and, along this path of rotation, the ball 58 has moved radially into the recess 54 again. Correspondingly, in this case, the volume of the further chamber 66 decreases, so as to give rise in the latter to overpressure which closes the second valve 74, while the first valve 72 is opened. The force opening in the first valve 72 is generated by the then high overpressure in the first subchamber 62 and in that section of the first duct 58 which issues into the subchamber 62. The further chamber 66 then communicates with the first subchamber 62, and a medium in the further subchamber 66 is pressed via the first duct 68 into the first subchamber 62 and from there through the gap between the housing inner wall 44 and the outside 50 of the rotor 26, in the region of the point 48, into the outlet 24.

The second subchamber 64, which has continuously increased in volume, starting from FIG. 4a) and b), continues to suck it in, so the medium continues to be admitted through the inlet 22 into the second subchamber 64.

The operating position in FIG. 5a) and b) is then followed again by the state in FIG. 2a) and b).

If the pump 10 is used as a vacuum pump or as a feed pump for a gaseous or liquid medium, the medium is sucked in continuously through the inlet 22 and discharged continuously through the outlet 24.

If the pump 10 is to be used for generating high pressure, an outlet valve, in particular a non-return valve, may be arranged in the outlet 24 and releases the outlet 24 only when a correspondingly high pressure, which opens the valve in the outlet 24, prevails in the first subchamber 62.

FIG. 6 illustrates an exemplary embodiment, modified with respect to FIG. 1, of a pump 110. Further details of the pump 110 are illustrated in FIG. 7a) to 8b).

The same reference symbols are used for identical or comparable parts in the pump 110 as in the pump 10, but increased by 100.

Primarily the differences between the pump 110 and the pump 10 are described below.

The pump 110 has an essentially cylindrical housing 112 in which is arranged a likewise essentially cylindrical rotor 126 which revolves in the housing about a housing-fixed axis of rotation 128 eccentric with respect to the housing centre. A displacement body 156 designed as a cylinder 158 is arranged in a recess 154 in the rotor 126.

An inner wall 160 of the recess 154 has an inner contour which is adapted to the surface contour of a cylinder 158.

A housing inner wall 144, along which the cylinder 158 runs when the rotor 126 rotates, is likewise designed with a surface contour which is adapted to the cylindrical surface of the cylinder 158. According to FIGS. 7b) and 8b), the housing inner wall 144 has, in a section parallel to the axis of rotation 128, an essentially rectangular form, and, as seen in the circumferential direction about the axis of rotation 128, the housing inner wall 144 has essentially the surface of a cylinder.

The cylinder 158 is arranged in the recess 154 such that its cylinder axis 159 runs parallel to the axis of rotation 128. In the same way as the ball 58 of the pump 10, the cylinder 158, when it revolves about the axis of rotation 128, rolls on the housing inner wall 144, with the result that losses due to friction are minimal.

The cylinder 158 is designed as a hollow cylinder.

The inner wall 160 of the recess 154 is likewise adapted to the surface contour of the cylinder 158 and is correspondingly in the form of a part-cylindrical surface area, so that the cylinder 158, in its position retracted radially into the recess 154 to the maximum, bears against the inner wall 160 along an approximately semicircular touching line, as illustrated in FIG. 7a).

The housing inner wall 144 has, in the circumferential direction about the axis of rotation 128, a region in which the housing inner wall 144 is spaced apart from an outside 150 of the rotor 126, so that a first chamber 152 is formed in this region between the outside 150 of the rotor 126 on the housing inner wall 144. When the cylinder 158 revolves about the axis of rotation 128, the first chamber 152 is subdivided into a first subchamber 162 and a second subchamber 164, as can be seen in FIG. 8a).

A further chamber 166 is formed between the cylinder 158 and the inner wall 160 of the recess 154, the further chamber 166 being connected to the first subchamber 162 via a first duct 168 and to the second subchamber 164 via a second duct 170.

A first valve 172 is arranged in the first duct 168 and a second valve 174 is arranged in the second duct 170.

In contrast to the pump 10, a plurality of first ducts 168 and a plurality of second ducts 170 are present in the rotor 126, specifically, in each case, three of both. FIG. 6 shows three first ducts 168 and correspondingly also three common sections 171 of the ducts 168 and 170. Preferably in each case a first valve 172 and in each case a second valve 174 are arranged in each of the plurality of first ducts 168 and plurality of second ducts 170.

The functioning of the first valve or valves 172 and of the second valve or valves 174 is identical to the function of the first valve 72 and of the second valve 74 of the pump 10.

The set-up and operation of the pump 110 are otherwise identical to the set-up and operation of the pump 10. FIG. 7a) and b) show the pump 110 in an operating position which corresponds to the operating position of the pump 10 in FIGS. 2a and b), and FIG. 8a) and b) show the pump 110 in an operating position which corresponds to the operating position of the pump 10 in FIG. 4a) and b).

When the displacement body 156 is configured as a cylinder 158, the selected length of the cylinder 158 and, correspondingly, the rotor 126 may be greater or lesser in order to achieve a corresponding pumping capacity. The rotor 126 may be of multi-part design in the direction of the axial rotation 128 or cylinder axis of the cylinder 158, which, in particular, also makes it simpler to introduce the first and second ducts 168, 170.

Claims

1. A pump, comprising a housing having a housing inner wall,a rotor arranged in the housing, the rotor having at least one recess, the rotor being rotatable in the housing about a housing-fixed axis of rotation,at least one displacement body received in the at least one recess of the rotor, the displacement body, when the rotor rotates about the housing-fixed axis of rotation, revolves about the axis of rotation and at the same time runs along on the housing inner wall of the housing, the displacement body being radially movable in the recess between a position retracted into the recess and a position extended out of the recess,a first chamber arranged between the housing inner wall and an outside of the rotor,a leading first subchamber and a trailing second subchamber, into which the displacement body, when revolving about the axis of rotation, subdivides the first chamber,a further chamber formed between the displacement body and an inner wall of the recess,a first duct connecting the leading first subchamber with the further chamber,a second duct connecting the trailing second subchamber with the further chamber,the further chamber, according to the radial movements of the displacement body which occur when the rotor revolves about the axis of rotation, is alternately increased in volume, with the result that an additional vacuum arises in the further chamber and in the second subchamber, and decreased in volume, with the result that an additional overpressure arises in the further chamber and in the first subchamber.

2. The pump of claim 1, wherein the displacement body has, on its side facing the inner wall of the recess, a surface contour which corresponds to the inner contour of the inner wall of the recess.

3. The pump of claim 1, wherein the housing inner wall, along which the displacement body runs, has a surface contour which corresponds to a surface contour of a side of the displacement body which faces the housing inner wall.

4. The pump of claim 1, wherein the displacement body is designed as a body of revolution which can rotate in the recess at least about an axis parallel to the axis of rotation.

5. The pump of claim 4, wherein the displacement body is a ball.

6. The pump of claim 5, wherein the ball is a hollow ball.

7. The pump of claim 5, wherein the inner wall of the recess is in the form of a part-spherical surface area.

8. The pump of claim 4, wherein the displacement body is a cylinder, a cylinder axis of which runs parallel to the axis of rotation.

9. The pump of claim 8, wherein the cylinder is a hollow cylinder.

10. The pump of claim 8, wherein the inner wall of the recess is in the form of a part-cylindrical surface area.

11. The pump of claim 1, wherein a first valve is arranged in the first duct, which first valve closes the first duct when the displacement body moves out of the retracted position to the extended position and which releases the first duct when the displacement body moves out of the extended position into the retracted position.

12. The pump of claim 1, wherein a second valve is arranged in the second duct, which second valve releases the second duct when the displacement body moves out of the retracted position to the extended position and closes the second duct when the displacement body moves of the extended position into the retracted position.

13. The pump of claim 11, wherein the first valve is controlled automatically by instantaneous pressures prevailing in the first duct on both sides of the first valve.

14. The pump of claim 12, wherein the second valve is controlled automatically by instantaneous pressures prevailing in the second duct on both sides of the second valve.

15. The pump of claim 11, wherein the first valve has a first valve disc and a first valve seat, the first valve disc closing against the first valve seat in direction towards the first subchamber.

15. The pump of claim 15, wherein the first valve disc is prestressed into a closing position of the first valve.

17. The pump of claim 14, wherein the first valve is arranged in the first duct such that the first valve disc and the first valve seat are oriented essentially in circumferential direction about the axis of rotation.

18. The pump of claim 12, wherein the second valve has a second valve disc and a second valve seat, the second valve disc closing against the second valve seat in direction towards the second subchamber.

19. The pump of claim 18, wherein the second valve disc is prestressed into a closing position of the second valve.

20. The pump of claim 18, wherein the second valve is arranged in the second duct such that the second valve disc and the second valve seat are oriented essentially in circumferential direction about the axis of rotation.

21. The pump of claim 1, wherein a plurality of first ducts and a plurality of second ducts are present in the rotor.