EP3508727A1 - Scroll pump and method for operating a scroll pump - Google Patents

Abstract

A scroll pump, in particular scroll vacuum pump, comprises at least one scroll pump stage for conveying a gas from a gas inlet through the scroll pump stage to a gas outlet and an electric motor having a stator and a rotor, the rotor for driving a movable part of the scroll pump stage with the movable part the scroll pump stage is coupled.

Description

The present invention relates to a scroll pump, in particular a scroll vacuum pump, with at least one scroll pump stage for conveying a gas from a gas inlet through the scroll pump stage to a gas outlet, and an electric motor having a stator and a rotor, the rotor for driving an orbiting portion of the Scroll pump stage is coupled to the orbiting part of the scroll pump stage. The present invention also relates to a method of operating such a scroll pump.

A scroll pump is a positive-pressure pump that compresses against atmospheric pressure and can be used, among other things, as a compressor. A scroll vacuum pump may be used to create a vacuum in a recipient connected to the gas inlet. Scroll vacuum pumps are used for example in the EP 0 798 463 A2 and the DE 199 14 770 A1 described.

Scroll vacuum pumps are also referred to as spiral vacuum pumps or spiral fluid conveyors. The pumping principle on which a scroll pump is based is known from the prior art and will be explained below. A pumping stage of a scroll pump has two nested, for example Archimedean spiral cylinders, which are also referred to below as spirals. Each spiral cylinder consists of an equidistant spiral wall with a provided on an end face of the spiral wall base plate. The spiral cylinders are inserted into one another such that the spiral cylinders partially enclose crescent-shaped volumes. One spiral is fixed, while the other spiral can be moved via an eccentric drive on a circular path. The movable spiral thus performs a so-called Centrally symmetric oscillation, which is also referred to as "wobble". A crescent-shaped volume trapped between the spiral cylinders continues to migrate within the spiral walls during wobble of the movable scroll, whereby by means of the traveling volume gas is delivered from a radially outer gas inlet radially inward to a gas outlet located in the spiral center.

According to the prior art, an electric motor configured as an asynchronous drive is used to drive the movable part of the scroll pump stage that has the movable spiral. The disadvantage of this is in particular that asynchronous electric motors have a relatively poor efficiency and can contribute to the emergence of relatively high temperatures in the scroll pump.

The present invention is therefore based on the object to provide a scroll pump with an improved electric drive.

The object is achieved by a scroll pump with the features of claim 1 and in particular by the fact that a scroll pump of the type mentioned is further developed in that a synchronous motor is used as the electric motor.

Synchronous motors have better efficiency compared to asynchronous motors. Therefore, a synchronous motor heats up less with the same output power than an asynchronous motor. For the same output power thus causes a synchronous motor less heating of the scroll pump. This has, inter alia, the advantage that the life of sealing materials used in the pump, which are normally made of plastic, can be extended. In particular, due to the lower heating of the scroll pump when using a synchronous motor - Life of so-called tip seals, as will be explained in more detail, be extended.

Furthermore, the use of a synchronous motor is advantageous in that the rotational speed of the rotor can be varied over a wide speed range. The suction power of a scroll pump is essentially determined by the height of the spiral walls, their spacing, the outer diameter and the speed of movement of the movable scroll relative to the fixed scroll. The speed of movement of the movable scroll is normally dependent on the speed of the rotor of the electric motor or, when a transmission is connected between the rotor and the movable scroll, is at least correlated with the speed of the rotor. By varying the speed of the rotor thus the suction power of the scroll pump can be changed. For example, at the beginning of pump operation to pump out a recipient connected to the gas inlet, the speed of the rotor and thus the suction power of the scroll pump can be set to a high value. After reaching a final pressure then the speed and accordingly the suction power can be reduced because the final pressure can be maintained even with lower suction. By reducing the rotational speed of the rotor, the power consumption of the electric motor can be reduced, whereby an energy saving can be realized. Taking into account that the evacuation pump-down process requires only a small fraction of the time compared to the rest of the pump operation, during which the final discharge pressure in the recipient only has to be maintained, a considerable reduction in the rotational speed of the rotor of the electric motor can be achieved Energy saving can be realized.

According to a preferred embodiment of the invention, the synchronous motor is a permanent magnet synchronous motor. The synchronous motor may be thus act to a PM synchronous motor, PM stands for permanent magnet.

Particularly preferably, the permanent magnet synchronous motor is designed such that each pole of the rotor has at least one embedded in the rotor permanent magnet. By embedding the permanent magnets in the rotor, a separate holder for the permanent magnets can be saved. In addition, the permanent magnets can be protected by the surrounding rotor from process gases. The permanent magnets may also be disposed on the surface of the rotor, e.g. stuck.

Preferably, a controller for controlling and / or regulating the rotational speed of the rotor is provided. Preferably, the controller is integrated in the pump.

The controller may be configured to control and / or regulate the rotational speed of the rotor as a function of a pressure and / or a temperature of the scroll pump. For measuring the pressure, the pump may have at least one pressure sensor. By means of the pressure sensor, for example, the pressure prevailing in the gas inlet pressure can be detected. For detecting a temperature of the pump, at least one temperature sensor may be provided. With the temperature sensor, for example, the temperature of the movable spiral or the fixed spiral or the temperature of a seal, in particular a tip seal, can be measured.

An advantage of a controller that controls or regulates the speed of the rotor in response to a pressure and / or a temperature of the scroll pump, in particular, that this can reduce the speed of the rotor after the final pressure is reached. As a result, as already explained above, an energy saving can be achieved. In addition, the speed of the rotor can be lowered when the temperature of the scroll pump a certain, predetermined or predefinable threshold. Since the movable scroll moves relative to the stationary scroll in a scroll pump, a friction results between the scrolls which, in conjunction with the effected compression of the gas, causes considerable heating in the scroll pump. By reducing the speed of the rotor and the relative movement of the spirals can be slowed down to each other, so that a smaller waste heat is generated. By changing or decreasing the speed of the rotor thus a further increase in the temperature of the scroll pump can be avoided or the temperature of the scroll pump can possibly even be lowered. With a suitable choice of the threshold temperature in particular a destruction or heavy wear on the seals of the scroll pump can be avoided.

According to a preferred embodiment of the invention, the controller is adapted to adjust depending on a, preferably predetermined by a user of the pump, operating parameters of the pump, such as a desired suction pressure or a desired suction, the speed of the rotor such that the operating parameters at least is almost reached. As a result of the adjustability of the rotational speed of the rotor, a related operating parameter, such as the intake pressure or the pumping speed, can thus be adjusted so that the operating parameter can actually be realized by the pump.

For example, the controller may allow a user of the pump to set the operating parameter. Thereafter, the controller may adjust the speed of the rotor so that the operating parameter is actually achieved. The control can also be a regulation. In order to achieve the operating parameter, for example, a comparison of the actual value of the operating parameter with a desired value can take place.

The controller may be configured to control the speed of the rotor in response to a pressure and / or to regulate so that the pumping speed of the pump changes according to a predetermined or predeterminable course. During the pumping out of a recipient, for example, the rotational speed of the rotor can be adjusted such that the pumping speed of the pump changes linearly or undergoes only slight fluctuations as seen during the pumping process. Absorbs of pumping, which can occur at certain pressures in the gas inlet, can be avoided thereby.

According to a preferred embodiment of the invention, the controller is designed to reduce the speed of the rotor upon reaching a certain pressure, in particular a final pressure, in particular by a predetermined or predetermined, certain amount. As stated above, reducing the rotational speed of the rotor may result in potentially significant energy savings.

Preferably, the controller is adapted to briefly switch off the electric motor on reaching a certain pressure, in particular a final pressure, or to operate at a predetermined or predetermined, in particular minimum, speed of the rotor. After reaching the final pressure, it is only necessary to keep this final pressure at least approximately. The pump can therefore be operated after reaching the final pressure at a lower suction power than is required to generate the final pressure. It is also possible to temporarily switch off the electric motor in order to achieve a corresponding energy saving. The duration of the shutdown can be chosen so that - for example based on empirically obtained data - it is ensured that no or only a slight increase in the pressure takes place in the recipient during shutdown. By operating the pump with a runner running at minimal speed can also achieve a significant energy savings and to ensure that the pressure in the recipient does not increase, or at most only slightly.

If it is provided that the controller shuts off the electric motor for a short time, it is advantageous if the controller is designed to re-operate the electric motor after switching off, for example, if after the switching off of the electric motor, a pressure increase is measured.

According to a preferred embodiment of the invention, a maximum allowable speed range for the rotor is specified for normal operation of the pump, and the controller is adapted to increase the speed of the rotor over the maximum allowable speed value. The pump can thus be operated in a kind of boost function in which a defined, normally maximum permissible speed value can be exceeded at least for a short time, in particular in order to realize a high pumping speed at the gas inlet of the pump for a short time. The boost function also compensates for possible slumps in the pumping speed.

In particular, the controller may be configured to increase the rotational speed of the rotor over the maximum permissible rotational speed value when a certain, predetermined pressure value and / or a certain, predetermined temperature in the pump, in particular at a provided in the pump seal, is achieved.

According to a preferred embodiment, which is also claimed as an independent invention, the rotor of the electric motor is arranged relative to the stator of the electric motor, that during operation of the electric motor, directed in an axial direction, axial force is generated on the rotor. The axial direction refers to a direction along the axis of rotation of the rotor. To generate the axial force of the rotor, based on its normal position to the stator, along the axial direction can be arranged offset to the stator. Preferably, the rotor is offset in relation to its normal position to the stator against the axial direction offset by an offset. Normal position means that position in which the center planes of rotor and stator, which run perpendicular to the rotation axis, lie one above the other.

The rotor may be coupled to the movable part of the scroll pump such that the axial force is transmitted to the movable part of the scroll pump stage. The movable part of the scroll pump stage can thus be acted upon during operation of the electric motor in the axial direction with the axial force.

As seen in the axial direction, between the movable part of the scroll pumping stage and an immovable part of the scroll pumping stage at least one seal can be arranged, which is compressed or pressed by the axial force between the movable and immovable part of the scroll pumping stage. By means of the axial force, the movable part of the scroll pumping stage can be biased in the direction of the immovable part of the scroll pumping stage and an intermediate seal, in particular a so-called tip seal, can thereby be compressed. Thereby, the effect of the seal can be improved.

The invention also relates to a method for operating a scroll pump, in particular a scroll vacuum pump, with at least one scroll pump stage for conveying a gas from a gas inlet through the scroll pump to a gas outlet and an electric motor having a stator and a rotor, wherein the rotor for driving a movable part of the scroll pump stage is coupled to the movable part of the scroll pump stage, and wherein in the method, the speed of the rotor is controlled and / or regulated in response to a pressure and / or a temperature of the scroll pump.

Fig. 1

einen Längsschnitt durch eine erfindungsgemäße Scrollvakuumpumpe,

Fig. 2A

einen Längsschnitt durch eine Pumpstufe einer Scrollvakuumpumpe,

Fig. 2B

einen Längsschnitt durch eine Pumpstufe einer weiteren Scrollvakuumpumpe,

Fig. 3

einen Querschnitt der Pumpstufe der Scrollvakuumpumpe von Fig. 1,

Fig. 4

einen Längsschnitt durch eine weitere erfindungsgemäße Scrollvakuumpumpe,

Fig. 5

einen Querschnitt durch einen Stator und Rotor eines SynchronElektromotors, und

Fig. 6A - 6E

verschiedene Abwandlungen von Rotoren für einen SynchronElektromotor.

The invention will now be described by way of example with reference to the accompanying drawings. Show, in each case schematically,

Fig. 1

a longitudinal section through a scroll vacuum pump according to the invention,

Fig. 2A

a longitudinal section through a pumping stage of a Scrollvakuumpumpe,

Fig. 2B

a longitudinal section through a pumping stage of another scroll vacuum pump,

Fig. 3

a cross section of the pumping stage of the scroll vacuum pump of Fig. 1 .

Fig. 4

a longitudinal section through another scroll vacuum pump according to the invention,

Fig. 5

a cross section through a stator and rotor of a SynchronElektromotors, and

FIGS. 6A-6E

various modifications of rotors for a synchronous electric motor.

In the Fig. 1 shown scroll vacuum pump 11 has a housing 13 in which a gas inlet 15 and a gas outlet 17 are provided. To the gas inlet 15, an outlet of a recipient, not shown, can be connected. A scroll pump stage 19 provided in the housing 13 can evacuate gas from the recipient through the gas inlet 15 and convey it through the scroll pump stage 19 to the gas outlet 17. The scroll pumping stage 19 has a movable part 21 and a fixed part 23. The mobile one Part 21 comprises a first, movable spiral cylinder 25. The fixed part 23 has a second, fixed spiral cylinder 27. The first spiral cylinder 25 and the second spiral cylinder 27 are hereinafter also referred to as first spiral 25 and second spiral 27. The first spiral 25 and the second spiral 27 are - as in scroll pumps known per se - nested. The first spiral cylinder 25 has a respective end face at each axial end. One of the end faces of the first spiral cylinder 25 is gas-tightly connected to a first wall 29 or integrally formed therewith. The first wall 29 effectively forms a base plate on which the spiral 25 is arranged. In a corresponding manner, one of the end faces of the second spiral cylinder 27 is gas-tightly connected to a second wall 31 or integrally formed therewith.

On the end face of the movable first spiral cylinder 25, which faces the fixed, second wall 31, a first seal 33 is arranged, which is also referred to as a tip seal. For example, a Tip Seal is a plastic compound (PTFE) with a rectangular cross-section.

Between the end face of the fixed second spiral cylinder 27, which faces the movable, first wall 29, a second seal 35 is also provided, which is also referred to as a tip seal. By the seals 33, 35 can be sealed by the spiral cylinders 25, 27, crescent-shaped volumes at the end faces of the spiral cylinders 25, 27 seal.

The gas inlet 15 opens into a suction region 37 (cf. Fig. 3 ) formed by the first and second scrolls 25, 27 in a radially outer region. The first spiral 25 moves on a circular path due to an eccentric drive 36 and performs a so-called center-symmetric oscillation, which is also referred to as "wobbling" or "orbiting". Between the spirals 25, 27 arise so completed crescent-shaped volumes or cavities, the to reduce their volume further and further inside. The gas is thus conveyed radially inwards via the suction region 37 via the cavities formed between the spirals 25, 27 and expelled through an ejection region 39 into the gas outlet 17 in the middle of the spiral.

As mentioned above, the eccentric drive 36 is used to drive the first scroll 25 and the movable part 21 of the scroll pump stage 19, respectively. The eccentric drive 36 comprises an eccentric shaft 41 which is mounted by means of a bearing 43 and has at its axial end a section 45 whose longitudinal axis L is offset parallel to the axis of rotation R of the eccentric shaft 41. The movable part 21 comprises a bearing 47, which is attached to the shaft portion 45, such as Fig. 1 shows. To compensate for the eccentric movement of the movable first spiral 25 balancing weights 49 are arranged on the eccentric shaft 41. In addition, a metallic bellows 51 between the inside of the housing 13 and the back 67 of the first wall 29 is arranged for hermetic sealing and rotation prevention.

For driving the eccentric shaft 41, a synchronous motor 53 is provided in the housing 13, which has a stator 55 and a rotor 57. The rotor 57 is coupled to the shaft 41 and thus to the movable part 21 of the scroll pump 19.

The synchronous motor 53 is preferably a permanent magnet-excited synchronous motor, in which the rotor 57 has a plurality of permanent magnets 59, preferably embedded in the rotor 57, such as Fig. 5 shows. The permanent magnets 59 can be inserted, for example, in slots provided in the rotor 57. The slots may be hermetically sealed to protect the permanent magnets, for example from corrosive gas.

The scroll pump 11 may further include a controller 61 coupled to the synchronous motor 53 and configured to control and / or regulate the rotational speed of the rotor 57. The controller 61 may have a, in particular sensorless, position detection of the rotor and advantageously also has a wide voltage input, for example, for supply voltages of 90 to 230 volts or, for example for supply voltages of 24 to 48 volts on.

The controller 61 can change the rotational speed of the rotor 57 and thus the rotational speed of the first spiral 25 almost arbitrarily. The abrasion of the seals 33, 35 during pump operation depends on the sliding speed of the seals 33, 35 on the walls 29, 31 and thus on the speed of the rotor 57. Other parameters that have an influence on the abrasion of the seals 33, 35 are the contact pressure of the seals 33, 35 on the walls 29, 31 and the temperature. The temperature can be at least indirectly influenced by the speed of the rotor 57, since at higher speed of the rotor 57 and higher temperatures occur in the pump. By adjusting the rotational speed of the rotor 57 during pump operation, the wear of the seals 33, 35 can be reduced and the temperature in the pump 11 can be influenced.

The speed of movement of the first spiral 25 and thus the speed of the rotor 57 also have a decisive influence on the pumping capacity or the pump capacity and the achievable final pressure or the compression ratio of the pump 11.

The scroll pump may have at least one temperature sensor 63 in the region of the pumping system, for example on the rear wall 67 of the first wall 29, and a pressure sensor 65, for example in the region of the gas inlet 15. The controller 61 may therefore be designed to control the rotational speed of the rotor 57 as a function of a pressure and / or a temperature of the scroll pump 11 to control and / or to regulate. This makes it possible, for example, when the temperature of the scroll pump exceeds a certain, predetermined or predefinable threshold, to lower the speed of the rotor 57 in order to achieve no further increase or possibly even a reduction in the temperature of the scroll pump.

The controller 61 may also be configured to adjust the rotational speed of the rotor 57 in accordance with a, for example, a user of the pump 11 predetermined or predetermined operating parameters of the pump 11, such as a desired suction pressure or a desired pumping speed such that the Operating parameters is achieved. As a result of the adjustability of the rotational speed of the rotor 57, a related operating parameter, such as, for example, the intake pressure or the pumping speed, can be achieved.

The controller 61 may allow a user to input an operating parameter and then adjust the speed of the rotor 57 so that the operating parameter is actually achieved. The controller may also be designed to control and / or regulate the rotational speed of the rotor 57 as a function of the pressure measured via the pressure sensor 65 in such a way that the pumping speed of the pump 11 changes in accordance with a predefined or specifiable profile. During the pumping out of the recipient, for example, the speed of the rotor 57, the pumping speed of the pump 11 can be adjusted so that it follows the predetermined course and thus, for example, only slight fluctuations occur. In particular, slumps in the pumping speed, which can occur at certain pressures in scroll pumps known from the prior art, can be avoided in this way.

Slumps in absorbency, especially through worn tip seals, can also be avoided by leveling or adjusting tip seals.

By a pressure-dependent speed control of the speed of the rotor 57, for example, a nearly linear Saugvermögensbereich or course can be achieved.

The controller 61 may be configured to reduce the speed of the rotor 57 upon reaching a certain pressure, for example a final pressure of the pump 11.

By means of the controller 61, a pressure-dependent speed control of the scroll pump can also take place. The user of the pump can preselect, for example, a suction pressure and the controller 61, depending on the upcoming gas load or the pressure measured by the pressure sensor 65, the speed of the rotor 57, as far as it is within the approved control range set.

The controller 61 may be designed to switch off the electric motor 53 at least for a short time when a specific pressure, in particular a final pressure of the pump 11, is reached or to operate at a predetermined or predefinable, in particular minimum, speed. After reaching the final pressure, it is only necessary to keep this final pressure. In this case, a lower suction power is required than during the actual pumping out of the recipient is required. Therefore, it is possible to temporarily shut off the synchronous motor 53 to achieve a corresponding energy saving. The duration of the shutdown can be selected so as to ensure that during shutdown no or only a slight increase in the pressure in the recipient takes place. The pump can after reaching the final pressure at a be operated predetermined minimum speed, on the one hand to keep the final pressure, but on the other hand to achieve energy savings.

The controller 61 may be configured to switch it on again after a shutdown of the motor 53, for example as a function of the pressure measured by the pressure sensor 65.

In the case of the vacuum pump 11, a maximum permissible rotational speed value for the rotor 57 can be predetermined for the normal operation of the pump. The controller 61 may be configured to monitor the speed of the rotor 57 and to ensure that the maximum allowable speed value is not exceeded during normal operation of the pump 11. However, the controller 11 may also be configured to increase the speed of the rotor 57 over the maximum allowable speed value. The pump 11 can thus be operated in a boost mode to realize a short time high pumping speed.

Unlike the scroll pump the Fig. 1 has the scroll pump 11 'of Fig. 4 a synchronous electric motor 53, in which the rotor 57 is arranged relative to the stator 55, that during the operation of the electric motor 53 in the axial direction, ie along the axis of rotation R, directed force F is generated on the rotor 57. By the axial force F, the first wall 29 is pressed in the direction of the second wall 31, whereby the seals 33, 35 between the movable and fixed parts 21, 23 of the scroll pump 11 are compressed. The sealing effect of the seals 33, 35 is thereby improved.

For generating the axial force of the rotor 57, as a comparison between the Fig. 1 and 4 shows, based on his in Fig. 1 shown normal position to the stator 55 against the axial direction offset by an offset V to the stator 55 is arranged. Between a plane perpendicular to the axis of rotation R center plane M1 of the stator 55 and also perpendicular to the axis of rotation R extending center plane M2 of the rotor 57 is thus provided the aforementioned axial offset V, due to which during the operation of the electric motor 53, the force acting in the axial direction F adjusts. By acting in the axial direction of force F not only the seals 33, 35 can be compressed or biased to increase the sealing effect, but it can also be the bearings 43, 47 are relieved. As a result, smaller and cheaper bearings can be used. Furthermore, the axial force F can be used to compensate for the compression forces in the pumping stage 19 in the axial direction and / or axial compressive forces in the pumping system.

The use of an electric motor 53 with an axial offset V between the stator 55 and the rotor 57 is suitable for use in connection with a single-wrap pumping stage (cf. Fig. 2B ) as well as in connection with a double-wrap pump stage (cf. Fig. 2A ). In the in the Fig. 1 and 4 shown pumping stages 19 are so-called single-wrap pumping stages. As Fig. 2B shows, the movable and the fixed scroll 25, 27 are arranged between the first and the second wall 29, 31, while on the back 67 of the second wall 29, no movable coil is provided. In contrast, in the double-wrap pumping stage according to Fig. 2A on the back 67 of the movable, first wall 29 also a movable spiral cylinder 69 is provided, which is inserted into one another with an immovable spiral cylinder 71, one end face with a third wall 73 gas-tight connected or formed integrally therewith. Between a front surface of the movable scroll 69 and the third wall 73, in turn, a seal 75 is provided, and between a front face of the fixed scroll 71 and the first wall 29, in turn, a seal 77 is provided. In the double-wrap arrangement are thus on both sides of the first wall 29 nested spiral cylinder. An advantage of a double-wrap arrangement is that a pressure compensation in the axial direction is achieved and thus lower axial forces act on the seals. The power consumption of the electric motor 53 can thereby be reduced.

In the Fig. 5 and 6A to 6E different arrangements of the permanent magnets 59 on the rotor 57 are shown.

According to Fig. 5 and accordingly Fig. 6B For example, the rotor 57 may have six rotor poles 79 in the circumferential direction U, each rotor pole 79 having one of the permanent magnets 59a-59f. The magnetization direction, which is directed from the south pole to the north pole, can be seen in the circumferential direction U in the permanent magnet 59a-59f alternately directed radially inward and radially outward. Therefore, in the permanent magnets 59a, 59c, and 59e, the magnetization direction may be directed radially outward while being directed radially inward of the permanent magnets 59b, 59d, and 59f.

In the runner 57 of Fig. 6A are the permanent magnets 59a - 59f attached to the radially outer side, for example glued, and thus not embedded. In the case of the permanent magnets 59a, 59c and 59e, in turn, the magnetization direction can be directed radially outward, while it is directed radially inward in the case of the permanent magnets 59b, 59d and 59f.

In the runner 57 of Fig. 6C each rotor pole on two permanent magnets, which are each arranged in a V-like and embedded in the rotor 57. One rotor pole comprises the permanent magnets 59a-1, 59a-2, another rotor pole comprises the permanent magnets 59b-1, 59b-2, another rotor pole comprises the permanent magnets 59c-1, 59c-2, another rotor pole comprises the permanent magnets 59d-1 59d-2, another rotor pole includes the permanent magnets 59e-1, 59e-2, and still another rotor pole includes the permanent magnets 59f-1, 59f-2. The direction of magnetization of the permanent magnets can in turn be directed in the circumferential direction from rotor pole to rotor pole radially outward or radially inward.

In the runner 57 of Fig. 6D The longitudinal direction of the permanent magnets 59a-59f extends in the radial direction. The magnetization can be directed radially outward in all permanent magnets 59a-59f.

In the runner 57 of Fig. 6E Each pole has four permanent magnets arranged in two rows in a V-shape. For the sake of simplicity, only the permanent magnets 59a-1, 59a-2, 59a-3, 59a-4 are marked with reference numerals. The direction of magnetization of the permanent magnets can in turn be directed in the circumferential direction from rotor pole to rotor pole radially outward or radially inward.

Each of the illustrated rotors 57 may be used in a synchronous motor 53 of the pump 11 or the pump 11 '.

LIST OF REFERENCE NUMBERS

11, 11 '

scroll pump

13

casing

15

gas inlet

17

gas outlet

19

Scroll pump stage

21

moving part

23

fixed part

25

first spiral cylinder

27

second spiral cylinder

29

first wall

31

second wall

33

first seal

35

second seal

36

eccentric

37

suction

39

discharge area

41

eccentric shaft

43

warehouse

45

shaft section

47

warehouse

49

counterweight

51

bellows

53

electric motor

55

stator

57

runner

59

permanent magnet

59a

permanent magnet

59b

permanent magnet

59c

permanent magnet

59d

permanent magnet

59e

permanent magnet

59f

permanent magnet

59a-1

permanent magnet

59a-2

permanent magnet

59a-3

permanent magnet

59a-4

permanent magnet

59b-1

permanent magnet

59b-2

permanent magnet

59c-1

permanent magnet

59c-2

permanent magnet

59d-1

permanent magnet

59d-2

permanent magnet

59e-1

permanent magnet

59e-2

permanent magnet

59f-1

permanent magnet

59f-2

permanent magnet

61

control

63

temperature sensor

65

pressure sensor

67

back

69

movable spiral cylinder

71

immovable spiral cylinder

73

third wall

75

poetry

77

poetry

79

rotor pole

L

longitudinal axis

R

axis of rotation

F

force

M1

midplane

M2

midplane

V

axial offset

U

circumferentially

Claims (4)

Scroll pump, in particular scroll vacuum pump, with at least one scroll pump stage (19) for conveying a gas from a gas inlet (15) through the scroll pump stage (19) to a gas outlet (17), and an electric motor (53) having a stator (55) and a rotor (57), wherein the rotor (57) for driving a movable part (21) of the scroll pump stage (19) is coupled to the movable part (21) of the scroll pump stage (19),
characterized in that the rotor (57) is arranged relative to the stator (55) such that during operation of the electric motor (53) along the axis of rotation (R) of the rotor (57) acting axial force (F) on the rotor (57) is generated. Pump according to claim 1,
characterized in that for generating the axial force (F) of the rotor (57) relative to its normal position to the stator (55) by an offset (V) against the axial direction offset from the stator (55) is arranged. Pump according to claim 1 or 2,
characterized in that the rotor (57) is coupled to the movable part (21) of the scroll pump stage (19) such that the axial force (F) is transmitted to the movable part (21) of the scroll pump stage (19). Pump according to one of claims 1 to 3,
characterized in that viewed in the axial direction between the movable part (21) of the scroll pump stage (19) and a stationary, fixed part (23) of the scroll pump stage (19) at least one seal (33, 35) is arranged, by the axial force (F) between the movable and the immovable part (21, 23) of the scroll pump stage (11, 11 ') is compressed or pressed.

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