EP3067560B1 - Vacuum pump with at least one pump stage - Google Patents

Description

The invention relates to a vacuum pump with at least one pump stage.

In vacuum technology, the term "backing pumps" is usually used to describe vacuum pumps that expel against the atmosphere. This name goes back to the fact that it is often used in combination with such vacuum pumps that can generate a high vacuum, but do not compress to atmospheric pressure. An example of such a high vacuum pump is the turbo molecular pump. Examples of backing pumps are vacuum displacement pumps, such as rotary vane pumps and piston pumps. The backing pumps are very often multi-stage, since the high vacuum pumps combined with them only generate a pressure of a few millibars at their gas outlet and therefore a large pressure range has to be bridged.

Both when used as a backing pump and when it is used to independently generate an ultimate vacuum in a recipient, the backing pump must first compress large amounts of gas. For the common design of a piston pump, this means that it must have a correspondingly large suction chamber. In these examples, the amount of gas that can be compressed per unit of time is dependent on the maximum pump chamber volume and the frequency with which the pump chamber is changed from its maximum to its minimum size. If there is little gas, the backing pump is oversized in terms of pump chamber volume and speed. However, the power consumption of the backing pump also depends on these values and it is desirable to minimize this.

To the state of the art ( DE 10 2006 050 943 A1 ) includes a vacuum pump with at least two pump stages, in which a gas pressure-sensitive signal transmitter is arranged between the two pump stages, which is in electrical connection with an evaluation unit, the evaluation unit in turn being connected to the motor control, so that a speed setting depending on the Signal generator given signal is possible.

From the state of the art ( DE 10 2008 061 897 A1 ) vacuum pumps are known, for example reciprocating piston pumps, which seals between the piston and the inner wall of the pump chamber exhibit. Since these seals create the contact between the piston and cylinder, these are so-called wear-prone seals that wear out over time. This also reduces the pumping capacity of the pump over time.

The same applies to so-called scroll pumps. Scroll pumps are also called spiral vacuum pumps or spiral fluid conveying devices. These pumps work on the positive displacement principle. A spiral vacuum pump consists of two nested spiral cylinders (e.g. Archimedes' spirals or involutes). One of these spirals is stationary, the other moves on a circular path via an eccentric drive (eccentric gear, eccentric shaft). One speaks of a centrally symmetrical oscillation ("wobbling"). This creates individual closed crescent-shaped cavities between the spirals, which continue to reduce their volume towards the inside. As a result, the fluid to be pumped, for example gas, is sucked in from the outside, compressed inside the pump and ejected through an opening in the center of the spiral.

The height of the spiral walls, their spacing and the speed define the suction power of a spiral vacuum pump.

Seals, which are in frictional contact with the stator, are arranged between the spiral cylinders forming the structure of the spiral and the bearing surface on the stator side. These seals wear out over time. When worn, the cavities become leaky and the suction power of the spiral vacuum pump decreases.

To the state of the art ( U.S. 5,718,565 A ) includes a dry compressing vacuum pump, in which with pressure gauges, whose sensors are located in the inlet or outlet of the pump stages to be monitored, pressure conditions are measured. As the build-up of deposits in the pump increases, the pressure ratio increases. This is recorded by the pressure measuring devices. This prior art vacuum pump can be further improved.

Furthermore, the state of the art ( JP 2003-139055A ) a dry compressing vacuum pump, in which a pressure measurement is carried out in an inlet area of the pump. This pump has no seals that are prone to wear.

In addition, the state of the art ( US 2001/001950 A1 ) a vacuum pump in which a sensor is arranged in a chamber to be evacuated. The sensor sits in front of a valve which is arranged between the chamber and the pump. There are no wear seals that would have to be monitored.

Furthermore, the state of the art ( DE 102 25 774 C1 ) a vacuum pump in which no sensor is arranged in front of a first pumping stage or in a compression chamber. This prior art pump can be further improved with regard to the monitoring of the seals prone to wear.

In addition, the state of the art ( US 2007/071610 A1 ) a method for controlling a drive motor of a vacuum displacement pump. The speed is controlled as a function of an inlet pressure. This prior art pump can be further improved with regard to the display for error detection.

Furthermore, the state of the art ( JP 2006-322405A ) an oil-lubricated vacuum pump. This pump has no seals that are prone to wear.

In addition, the state of the art ( CA 2752655 A1 ) a vacuum pump. This prior art pump has a pressure sensor which is arranged upstream of an inlet valve. The sensor detects the pressure, which indicates a defective seal. This prior art vacuum pump can be improved even further with regard to fault detection.

The technical problem on which the invention is based consists in this vacuum pump, which belongs to the prior art To be further improved to the effect that the service life of wear-prone seals in the vacuum pump is increased. In addition, a method is to be specified with which the wear on seals in the vacuum pump can be detected at an early stage.

This technical problem is solved by a vacuum pump having the features according to claim 1.

The vacuum pump according to the invention with at least one pump stage, a motor and a motor controller, the vacuum pump being designed as a dry-running pump with seals subject to wear, in which at least one pressure sensor is arranged in front of the first pump stage and / or in at least one compression chamber of the vacuum pump and in which the Pressure sensor is connected to an evaluation unit, with a display device being provided to display a defective and / or reduced performance of the vacuum pump, is characterized in that a signal line leads from the pressure sensor to an evaluation unit, which in turn is connected to a motor control and that so that wear on the seals is detected.

The vacuum pump according to the invention can be designed as a piston pump, for example a reciprocating piston pump. This reciprocating piston pump has at least one pump stage. The vacuum pump according to the invention can also be designed as a scroll pump with at least one pump stage.

The inventive arrangement of the at least one pressure sensor upstream of the first pumping stage and / or in at least one compression chamber of the vacuum pump makes it possible to carry out a more precise measurement of the pressure that can be generated, thereby enabling more precise control of the speed is possible than with a pressure switch between the pump stages.

If the pressure can no longer fall below a certain value, it can be assumed that the seals are used up.

According to the invention it is provided that a display device is provided for displaying a defective and / or reduced performance of the vacuum pump. If, for example, when closing the additional valve for closing the suction opening of the vacuum pump, a predetermined final pressure is not reached, it can be assumed that the seals are subject to a certain degree of wear. This reduced output is shown in the display device so that the user of the vacuum pump can read the current pressure value.

The user can also be informed on the display device that maintenance of the vacuum pump is necessary. The display device can have a display or at least one LED. Acoustic signals can also be emitted.

According to an advantageous embodiment of the invention, the at least one pressure sensor is arranged in the suction area of the vacuum pump. This enables the speed to be controlled very precisely, since the pressure sensor can be used to detect how high the suction pressure of the vacuum pump is.

Another particularly preferred embodiment of the invention provides that an additional valve is provided for closing a suction opening of the vacuum pump.

The vacuum pump has a suction opening. The suction opening is connected to a recipient.

According to the preferred embodiment of the invention, this suction opening is closed by an additional valve. By closing the valve, the vacuum pump can carry out an independent check of the final pressure, for example when the vacuum pump is switched on. From this final pressure, the vacuum pump can deduce the wear of the seals, i.e. the piston seals or the seals of the scroll pump.

The final pressure is checked in the relatively limited and small space of the intake flange. The measurement takes place independently of the recipient.

According to a further advantageous embodiment of the invention it is provided that the at least one sensor is designed as a Pirani sensor. Pirani sensors are very reliable sensors.

However, it is also possible to use other pressure measuring devices than Pirani sensors.

The vacuum pump is advantageously designed as a scroll pump. A scroll pump is a dry-running pump. Dry-running pumps are pumps that do not use auxiliary fluids, such as oil, in the area of the work area and in which a contamination of the working medium can be avoided.

A method for operating a scroll pump or a vacuum pump with at least two pump stages can provide that im Pump operation of the pressure sensor a gas pressure in the suction area and / or in at least one compression chamber of the vacuum pump measures that the measured value (s) of the pressure sensor is or are evaluated by an evaluation unit and that the speed of the pump is set as a function of an evaluation result.

The method has the advantage that by measuring the achievable pressure, i.e. the gas pressure in the suction area and / or in at least one compression chamber of the vacuum pump, the condition of the pump, in particular the seals, can be precisely recorded. For this purpose, the measured value or values of the pressure sensor are evaluated by an evaluation unit. The evaluation unit advantageously stores the range in which the measured values ideally lie. The speed of the pump is set as a function of the evaluation result.

For example, high speeds are set at high inlet pressures and low speeds at low inlet pressures in order to achieve optimum pumping speed.

A method not belonging to the invention for operating a vacuum pump or a scroll pump is characterized in that when the vacuum pump is started, a valve which has a The suction area separates from a recipient, it is concluded that the pressure sensor measures a gas pressure in the suction area closed against the recipient and / or in at least one compression chamber of the vacuum pump, that the measured value or values of the pressure sensor are evaluated by an evaluation unit and that depending on an evaluation result information is output from the display unit regarding the wear of seals.

The method has the advantage that the vacuum pump can carry out an independent check of the final pressure when it starts. From the final pressure the evaluation unit of the vacuum pump can deduce the wear of the seals.

According to a particularly preferred embodiment of the invention, the speed is regulated as a function of a measured value given by the at least one pressure sensor. If the pressure sensor measures a high inlet pressure, the speed can be increased. At low inlet pressures, the speed is reduced in order to achieve an optimal pumping speed.

According to a further advantageous embodiment of the invention it is provided that a switch is made between two rotational speeds depending on the measured value given by the at least one pressure sensor.

In a motor control, the speed is set depending on the evaluation result. This can be a switching process between two or more specified speeds. However, this can also be a continuous process in which the engine control electronics change the speed it generates as a function of a measured value transmitted to it.

According to a particularly preferred embodiment of the invention, it is provided that if the suction pressure falls below a predetermined value, the vacuum pump automatically lowers the speed or changes to a standby mode.

The speed is advantageously reduced when the signal from the pressure sensor reaches a pressure below this the atmospheric pressure corresponds. In an advantageous development, this pressure can be a pressure close to the ultimate pressure of the vacuum pump. The quantities of gas to be conveyed are particularly small here, so that the speed can be reduced further. By lowering the speed, the wear-prone seals can be protected, so that the service life of the seals is significantly increased.

The pump advantageously automatically switches to stand-by mode when the suction pressure has fallen below a certain limit value.

According to a further advantageous embodiment, if the suction pressure falls below a specified value, information on the wear of seals is displayed on the display. This embodiment has the advantage that the user of the pump can see when the seals are worn out and need to be replaced in order to ensure the optimal pumping speed of the pump.

Fig. 1

einen Längsschnitt durch eine Scrollpumpe;

Fig. 2

einen Querschnitt durch zwei orbitierende Scheiben einer Scrollpumpe;

Fig. 3

einen Längsschnitt durch eine Hubkolbenpumpe;

Fig. 4

eine erfindungsgemäße Anordnung eines Druck-sensors;

Fig. 5

einen Querschnitt durch verschiedene Dichtungen.

Further features and advantages of the invention emerge from the accompanying drawing, in which several exemplary embodiments of a housing according to the invention of a Roots pump are shown only as examples. In the drawing show:

Fig. 1

a longitudinal section through a scroll pump;

Fig. 2

a cross section through two orbiting disks of a scroll pump;

Fig. 3

a longitudinal section through a reciprocating pump;

Fig. 4

an inventive arrangement of a pressure sensor;

Fig. 5

a cross-section through various seals.

Fig. 1 shows a spiral vacuum pump 1 with a first stage 2 and a second stage 3. The invention also works with single-stage spiral vacuum pumps. The first stage 2 consists of an orbiting disk 4 and a stator 5. The orbiting disk 4 carries a spiral 6. The stator 5 carries a spiral 7. The spirals 6 and 7 are arranged in an interlocking manner. The spiral 6 seals against the stator 5. For this purpose, the stator 5 can have a so-called hard coat coating or some other hard coating on a counter surface 8. The orbiting disk 4 is in three shafts 9, of which in Fig. 1 only two shafts are shown, orbiting. The shafts 9 are rotatably mounted in a stator 10 by means of ball bearings 11.

The second stage 3 also has an orbiting disk 12 and a stator 13. The disk 12 carries a spiral 14, the stator 13 carries a spiral 15. The spirals 14, 15 are also arranged in an interlocking manner. The orbiting disk 12 is mounted in ball bearings by means of the shafts 9 in the stator disk 10. The shafts 9 have a shaft section 16 which is mounted in the stator 10. The shafts 9 also each have two shaft sections 17, 18 which are offset from the shaft section 16. The orbital movement of the disks 4, 12 is caused by the offset 17, 18.

The orbiting movement is driven by means of an electric motor which consists of a motor stator 19 and a motor orbiter 20. The motor orbiter 20 consists according to Fig. 1 made of permanent magnets. The motor stator 10 has excitable electromagnets which, when supplied with current, cause the orbiting movement of the disks 4, 12 and thus the spirals 6, 14. If the electric motor, that is to say the electromagnet 19 thereof, is energized, the electric motor acts as a drive so that the in the spaces between the two spirals 6, 7; 14, 15 arranged gas is compressed. The gas is transported from an inlet 21 of each stage 2, 3 to an outlet 22 and is compressed in the process.

A corrugated bellows 24 is provided in each pumping stage to seal off pumping spaces 23. The bellows can also serve as an anti-rotation mechanism if necessary. A check valve 25 is arranged in each of the outlets 22. The non-return valve 25 prevents the spiral vacuum pump 1 from being ventilated back after the drive 18, 19 has been switched off. Thus, the spirals 6, 7; 14, 15 against the specified direction of rotation can be avoided.

In addition, a gas ballast valve 26 is provided in each pumping stage. Gas is pumped from the atmosphere through the gas ballast valve 26 into the pump chamber 23 in order to avoid condensation of the gas to be pumped.

The relative movement of the spirals 5, 6; 14, 15 and the associated friction results in a not inconsiderable waste heat in connection with the compression of the gas. High temperatures lead to increased wear components, especially seals (in Fig. 1 not shown) between the spiral 6 and the counter surface 8 and the spiral 14 and the counter surface 27 at. For this reason, fans 28, which are only shown schematically, are provided in order to dissipate the heat by means of forced convection.

Since the orbiting disks 4, 12 are mounted by means of three shafts 9, no anti-rotation device is required. The corrugated bellows 24 serve only to seal off the pump spaces 23. In principle, the corrugated bellows 24 can also serve as a rotation-preventing mechanism.

If the scroll vacuum pump 1 has only one shaft, a rotation preventing mechanism is required. This task can be taken over by the corrugated bellows 24, for example. The scroll vacuum pump 1 can also have two or more shafts. With more than two shafts, an anti-rotation mechanism is usually not required.

The shafts 9 are rotatably mounted in the disks 4, 12 via ball bearings 11.

The electric motor 19, 20 can also be constructed in such a way that the motor orbiter 20 consists of a soft magnetic material, for example iron. The electromagnets arranged in the motor stator 19 can for example be designed as coils. In principle, there is also the possibility of forming the motor orbiter 20 from electromagnets and the motor stator 19 from permanent magnets or from a soft magnetic material, for example.

The spiral 6 carries seals 29. The spiral 7 carries seals 30.

Fig. 2 shows the spiral vacuum pump 1 with the spirals 6 and 7. The spirals 6 and 7 form compression spaces 23a, 23b; 54a, 54b; 55a, 55b. The pressure sensor or sensors can be located in the compression spaces 23a, 23b; 54a, 54b; 55a, 55b. In addition, in the area of a pump inlet 21 (in Fig. 1 ) at least one additional pressure sensor can be provided.

There is also the possibility of each having a pressure sensor in opposite compression spaces 23a, 23b; 54a, 54b; 55a, 55b or in adjacent compression spaces 23a, 54a, 55a; 23b, 54b, 55b to be arranged. A corresponding evaluation signal can be generated by the respective pressure difference.

Fig. 3 shows a reciprocating piston pump 101 with a housing 102. The housing 102 receives a shaft 104 which is rotatably supported in shaft bearings 106, 107. The shaft 104 carries permanent magnets 108 which interact with stationary coils 110 in such a way that the shaft 104 is set in rotation. In this sense, coils 110 and permanent magnets 108 form the drive of the reciprocating piston pump 101. The energization of the coils 110 necessary for the rotation is done by control electronics (not shown). One end of the shaft 104 protrudes into a crank chamber 112. A crank disk 114, which carries a crank pin 116, is connected to this end of the shaft 104. Depending on the design of the housing part, which includes the drive and the bearing, a shaft seal 118 to the crank chamber 112 is necessary so that this can be evacuated.

A cylinder 120, which receives a cylinder liner 122, is connected to the housing 102 in a gas-tight manner. The liner 122 is over part of its longitudinal axis with a Shrink fit fitted into the bore of the cylinder 120. In the bushing 122 there is a reciprocating piston 124 which is connected to the crank pin 116 via a connecting rod 126. As a result of this connection, the reciprocating piston 124 performs a periodic movement. In the in Fig. 3 In the example shown, the crank drive consisting of shaft 104, crank disk 114 and crank pin 116 causes a reciprocal movement between two reversal points.

The first reversal point 127 lies between the end of the cylinder liner 122 facing the crank chamber 112 and gas inlet bores 128, which are provided distributed over the circumference of the cylinder liner 122 and produce a gas connection to an inlet channel 130. This inlet channel 130 surrounds the liner 122 at least in sections in the circumferential direction and is in turn in gas connection with the pump gas inlet 132.

The second reversal point 133 lies near the end of the liner 122 facing away from the crank chamber 112. It is dimensioned such that the reciprocating piston 124 touches a valve cover 134 and lifts off the end of the liner 122. This end of the liner 122 forms the valve seat on which the valve cover 134 sits in the other phases of the reciprocating piston stroke. The valve cover 134 is provided with a layer 136 which dampens the contact between the valve cover 134 and the piston 124 and creates a seal. The valve cover 134 is pretensioned in the direction of the bushing 122 by a valve spring 138. If the reciprocating piston 124 is in the vicinity of the second reversal point 133, gas is ejected from a suction chamber 140 into an outlet chamber 142. From there it then arrives at a pump gas outlet 144 which, together with the outlet chamber 142, valve cover 134 and valve spring 138, is arranged in a cylinder cover 146 connected to the cylinder 120 in a gas-tight manner. Between the inner wall of the liner and piston 124 a seal 148 is arranged. This seals the gap between the liner 122 and the reciprocating piston 124 and thus the pump chamber 140 from the crank chamber 112. This seal 148 is exposed to wear due to the friction on the inner wall of the liner. A heat-conducting body 150 is in heat-transferring contact with the liner 122. The material of this heat-conducting body 150 has a higher coefficient of thermal conductivity than the material of the cylinder 120 receiving the liner 122. An aluminum alloy is typically used for the cylinder 120. Copper is a suitable material for the heat conducting body. Other materials with an even higher thermal conductivity than copper can advantageously be used. The heat conducting body 150 forms a thermal connection between the liner 122 and a space outside the cylinder 120. It can be cooled by convection of the ambient air or by thermal contact with an external cooling circuit (not shown).

A space 152 to be evacuated is arranged in front of the pump gas inlet 132. A pressure sensor 51 is arranged directly in front of the pump gas inlet 132 (only shown schematically).

The pressure sensor 51 is designed as a gas pressure sensitive sensor. This can be a Pirani sensor, for example.

By arranging the pressure sensor 51 in the area of the gas inlet 132, the vacuum pump 101 can automatically switch to a standby mode when the suction pressure has fallen below a certain limit value. The measurement directly in the suction area 152 enables precise control of the speed of the reciprocating piston pump 101. If the pressure cannot fall below a certain value, used piston seals 148 or seals 29 of the in the Fig. 1 and 2 scroll vacuum pump 1 shown go out.

A signal line 52, shown only schematically, leads from the pressure sensor 51 to an evaluation unit 53, also shown only schematically, which in turn is connected to a motor control 50. With the embodiment described so far, it is possible to detect wear of the seals 29, 148 and either to carry out maintenance or to reduce the speed of the pump 101.

Fig. 4 shows a reciprocating piston pump 31 with a first pump stage 43 and a second pump stage 44. The reciprocating piston pump 31 has a gas inlet 45, shown schematically, as well as a gas duct 46 and a gas outlet 47.

A drive unit 148 displaces the pistons (in Fig. 4 not shown) of the pump stages 43, 44 in a lifting movement, so that a medium to be conveyed, for example a gas, is transported from the gas inlet 45 via the gas guide 46 in the direction of the gas outlet 47.

The drive unit 48 has a motor 49 and a motor control 50.

A pressure sensor 51 is arranged in the area of the gas inlet 45. The pressure sensor 51 is designed as a gas pressure sensitive sensor. This sensor can be a Pirani sensor, for example.

By arranging the pressure sensor 51 in the area of the gas inlet 132, the vacuum pump 101 can automatically switch to a standby mode when the suction pressure has fallen below a certain limit value. By measuring An exact control of the speed of the reciprocating piston pump 101 is possible directly in the suction area 152. If the pressure cannot fall below a certain value, used piston seals of the reciprocating piston pump 101 or seals 29 of the in the Fig. 1 and 2 scroll vacuum pump 1 shown go out.

A signal line 52 leads from the pressure sensor 51 to an evaluation unit 53, which in turn is connected to a motor control 50. With the embodiment described so far, it is possible to detect wear of the seals 29, 148 and either perform maintenance or reduce the speed of the pump 1, 31, 101.

Another embodiment is optionally described below. This further embodiment has a valve 54, which, for example, on the suction flange 132 of the reciprocating piston pump 101 Fig. 3 is arranged. The suction flange 132 can be closed with the valve 54 so that the vacuum pump 31, 101 can carry out an independent check of the final pressure when it is started. From this final pressure the vacuum pump 31, 101 can deduce the wear of the piston seals 148. The valve 54 is closed by a controller 56 via a signal line 55. A display or an LED can be arranged in the evaluation unit 53 or separately therefrom in order to indicate that maintenance is required, that is to say that the seals 42 need to be replaced.

Closing the valve 54 has the advantage that a final pressure in the area of the suction flange can be determined independently of the recipient.

Once the self-diagnosis has been completed, the valve 54 is opened and the pump 31 is ready for use.

The vacuum pump 31 in Fig. 4 is only shown as an example. It may just as well be arranged according to Fig. 4 a scroll pump can be provided as described in Fig. 1 is shown.

The scroll pump can be constructed in one or more stages.

Fig. 5 shows the disc 5 of the scroll pump 1 of Fig. 1 with the spiral 7 and the disk 4 with the spiral 6. In Fig. 5 several ways of sealing the spirals 6, 7 to the disks 4, 5 are shown.

A spiral section 242 has a structured surface. In the present case, the surface is sawtooth-like in cross section. By means of a correspondingly selected narrow gap 243, the gap seals off the spiral section 242 from a mating surface 244 of the disk 4.

A spiral section 245 of the spiral 6 has an elastic carrier material 246 and a seal 247. The seal 247 rests on the opposing surface 8 and thus seals against the opposing surface 8. The seal 247 is adjusted by the elastic carrier material 246 when the seal 247 is worn. The mating surface 8 advantageously has a so-called hard coat coating in order to minimize wear.

A spiral section 248 also has a seal 249. The seal 249 is arranged in a channel 250 of the spiral section 248, that is to say in the stationary one Spiral 7. The seal 249 seals against the mating surface 244.

The seal 249 is rectangular in cross section, as in FIG Fig. 5 shown. A length L is greater than a width B of the seal 249. The seal 249 is arranged in the channel 250 such that a gap 251 remains in the area of the narrow side with the width B and a gap 252 remains in the area of the longitudinal side of the seal 249.

This means that the seal 249 is designed to be more flexible in the radial direction than in the axial direction. The gas to be pumped and compressed arrives in column 251, 252. In this way, the seal 249 is automatically adjusted when the seal is worn, so that a sealing effect between the seal 249 and the mating surface 244 is ensured over a long period of time.

If a predetermined inlet pressure is measured in the area of the pressure sensor 51, the speed of the vacuum pumps 1, 31, 101 can be reduced so that the wear on the seals 29, 148 is additionally minimized.

Reference numbers

1

Spiral vacuum pump

2

Pumping stage

3

Pumping stage

4th

orbiting disk

5

stator

6

spiral

7th

spiral

8th

Counter surface

9

wave

10

stator

11

ball-bearing

12

orbiting disk

13th

stator

14th

spiral

15th

spiral

16

Shaft section

17th

Shaft section

18th

Shaft section

19th

Motor stator

20th

Motor orbiter

21st

inlet

22nd

Outlet

23

Pumping rooms

23a

Compression space

23b

Compression space

24

Bellows

25th

check valve

26th

Gas ballast valve

27

Counter surface

28

Fan

29

poetry

30th

poetry

31

Reciprocating pump

43

Pumping stage

44

Pumping stage

45

Gas inlet

46

Gas routing

47

Gas outlet

48

Drive unit

49

engine

50

Motor control

51

Pressure sensor

52

Signal line

53

Evaluation unit

54a

Compression space

54b

Compression space

55a

Compression space

55b

Compression space

101

Piston vacuum pump

102

casing

104

wave

106

Shaft bearing

107

Shaft bearing

108

Permanent magnets

110

Do the washing up

112

Crankcase

114

Crank disc

116

Crank pin

118

Shaft seal

120

cylinder

122

Liner

124

Reciprocating piston

126

Connecting rod

127

first turning point

128

Gas inlet holes

130

Inlet port

133

second turning point

134

Valve cover

136

layer

138

Valve spring

140

Ladle room

142

Outlet chamber

144

Pump gas outlet

146

Cylinder cover

148

poetry

150

Heat conducting body

152

recipient

154

management

242

Seals

243

gap

244

Counter surface

245

Spiral section

246

elastic carrier material

247

poetry

248

Spiral section

249

poetry

250

channel

251

gap

252

gap

A.

Arrows

B.

width

L.

length

Claims (6)

1. A vacuum pump with at least one pumping stage, a motor and motor control, wherein the vacuum pump is configured as a dry-running vacuum pump with seals, in which there is arranged at least one pressure sensor (51) before the first pumping stage (43) and/or in at least one sealing space (23a, 23b; 54a, 54b; 55a, 55b) of the vacuum pump, and the pressure sensor (51) is connected to an evaluation unit (53),
   wherein a display device is provided for indicating a non-performance and/or underperformance of the vacuum pump (1, 31, 101),
   characterised in that the seals are seals which are subject to wear and
   in that a single line (52) leads from the pressure sensor (51) to an evaluation unit (53), which in turn is connected to a motor control (50) and in that a wear of the seals (29, 148) is detected thereby.
2. A vacuum pump according to claim 1, characterised in that the at least one pressure sensor (51) is arranged in the suction region (45) of the vacuum pump (1, 31, 101).
3. A vacuum pump according to claim 1 or 2, characterised in that an additional valve (54) is provided for closing a suction opening (45) of the vacuum pump (1, 31, 101).
4. A vacuum pump according to any one of the preceding claims, characterised in that the at least one sensor (51) is configured as a Pirani sensor.
5. A vacuum pump according to any one of the preceding claims, characterised in that the vacuum pump (1) is configured as a scroll pump.
6. A vacuum pump according to any one of claims 1 to 5, characterised in that the vacuum pump is configured as a piston pump (101).

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