METHOD FOR OPERATING A SCROLL VACUUM PUMP

Abstract

Method for operating and in particular monitoring a scroll pump, with the steps of: producing a vacuum by means of the scroll pump; determining a pressure of the scroll pump; comparing the recorded pressure with a pre-set threshold value; and if the recorded pressure lies above the pre-set threshold value, emitting a warning signal. The invention furthermore concerns a scroll pump for executing the method.

Claims

1. A method for operating and in particular monitoring a scroll pump, with the steps of: a) creating a vacuum by means of the scroll pump; b) determining a pressure of the scroll pump; c) comparing the recorded pressure with a pre-set threshold value; and d) if the recorded pressure lies above the pre-set threshold value, emitting a warning signal; characterized in that the recorded pressure is an end pressure and, wherein the warning signal corresponds to a remaining running time predicted from the end pressure that has been reached.

2. A method for operating and in particular monitoring a scroll pump, with the steps of: a) creating a vacuum by means of the scroll pump; b) recording a first pressure of the scroll pump and a second pressure of the scroll pump; c) comparing the difference between the first pressure and the second pressure with a pre-set threshold value; and d) if the pressure difference lies below the pre-set threshold value, emitting a warning signal; characterized in that an end pressure is determined from the pressure difference and, wherein the warning signal corresponds to a remaining running time predicted from the end pressure that has been reached.

3. The method according to claim 1, in which the pressure at the inlet of the scroll pump is recorded and/or within a scroll mechanism of the scroll pump.

4. (canceled)

5. The method according to claim 1, in which before the production of the end pressure, this step is carried out: closing of an intake valve arranged at the inlet of the scroll pump.

6. The method according to claim 1, in which the warning signal is an optical signal and/or an acoustic signal and/or a data signal that can be transmitted by means of a communication device.

7. (canceled)

8. The method according to claim 1, in which the method is implemented at pre-set time intervals or on the basis of an input signal.

9. The method according to claim 1, in which during operation, the operating pressure is measured at the inlet of the scroll pump, and if the measured operating pressure falls below a second threshold value, the rotational speed of the scroll pump is reduced.

10. The method according to claim 1, in which the intake valve is closed when the scroll pump is switched off and/or in the event of a malfunction of the scroll pump.

11. The method according to claim 1, in which a gas load is recorded and the end pressure or pressure difference is not recorded if a gas load is present.

12. A scroll pump with a housing which has an inlet and an outlet, a control device connected to the scroll pump, at least one pressure sensor arranged on the scroll pump to record a pressure of the scroll pump, wherein the pressure sensor is connected to the control device, wherein the control device is designed to implement the method according to claim 1.

13. The scroll pump according to claim 12, characterised in that the pressure sensor is arranged at the inlet of the scroll pump.

14. The scroll pump according to claim 12, characterised in that the recorded pressure is an operating pressure.

15. The scroll pump according to claim 12, characterised in that the pressure sensor is arranged within a scroll mechanism of the scroll pump.

16. The scroll pump according to claim 12, characterised in that at least two pressure sensors are provided, to record a first pressure and a second pressure, wherein the recorded pressure is determined from the difference between the first pressure and the second pressure.

17. The scroll pumps according to claim 12, characterised in that an intake valve is arranged at the inlet, wherein the intake valve is connected to the control device, wherein the control device is designed to close the intake valve to determine the end pressure.

18. The scroll pumps according to claim 12, characterised in that the control device and/or the pressure sensor and/or the intake valve are arranged in the housing of the scroll pump.

19. The scroll pumps according to claim 12, characterised by a communication device for transmitting an operating pressure that has been recorded by means of the pressure sensor and/or the recorded end pressure and/or the warning signal that has been generated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In the following, the invention is elucidated further on the basis of preferred embodiments, with reference to the enclosed drawings.

[0048] In the drawing,

[0049] FIG. 1A shows a side cross section of a scroll pump,

[0050] FIG. 1B shows an end cross section of the scroll pump of FIG. 1A.

[0051] FIG. 2 shows a detailed view of the scroll pump,

[0052] FIG. 3 shows a process flow of the method according to the invention,

[0053] FIG. 4 shows a schematic representation of the scroll pump according to the present invention, and

[0054] FIG. 5 shows a process flow of a further embodiment of the method according to the invention.

DETAILED DESCRIPTION

[0055] FIG. 1A shows a cross section of a scroll pump with a housing which defines an inlet 12 and an outlet 14. Connected to the housing is a first scroll element 16 which acts as a stator. Furthermore, arranged in the housing 10 is a second scroll element 18, wherein the second scroll element 18 orbits around the first scroll element 16. Here, the second scroll element 18 is connected to a shaft 20 that is driven by an electric motor 22, so that the second scroll element 18 is rotated around a common axis 34.

[0056] The first scroll element 16 has a base 26 and an essentially spiral first wall 28, which extends from the base 26.

[0057] Furthermore, the second spiral element 18 has a second base 30 and an essentially spiral second wall 32 which extends from the second base 30 and engages into the first wall 28, or fits into it. The first wall 28 and the second wall 32 define at least a part of a pump chamber 33, so that during the movement of the second scroll element 18, a gaseous medium is conveyed from the inlet 12 to the outlet 14.

[0058] FIG. 2 shows an example of a detailed view of the first wall 28. Here, the first wall 28 of the first scroll element 16 has a first end 40 which faces the second base 30 of the second scroll element 18, and is arranged opposite the first base 26 of the first scroll element 16. Arranged on the first end 40 of the first wall 28 is a seal element 42 which is in contact with the second base 30 of the second scroll element 18. Here, the seal element extends at least over a part and preferably over the whole length of the essentially spiral first wall 28. In the same way, a seal element is provided at the end of the spiral wall of the second scroll element 18, which is in contact with the base 26.

[0059] Due to the contact between the seal element 42 and the surface 44 of the second scroll element 18 lying opposite, because of the relative movement between the first scroll element 16 and the second scroll element 18, wear is sustained by the seal element 42. Through this wear, the sealing action of the seal element 42 is reduced, so that the gas-tightness of the respective pump chambers 33 is reduced and the output of the scroll pump is likewise reduced.

[0060] FIG. 3 shows a flow diagram according to the method according to the invention, for the operation and/or monitoring of a scroll pump, with the steps of: [0061] a) creating an end pressure by means of the scroll pump, S01; [0062] b) recording the end pressure that has been achieved at the inlet of the scroll pump, S02; [0063] c) comparing the end pressure that has been achieved with a pre-set threshold value, S03; and [0064] d) if the achieved end pressure lies above the pre-set threshold value, emitting a warning signal, S04.

[0065] Thus on the basis of the end pressure that has been achieved, a decision can be made as to whether the seal elements 42 need to be replaced or not. Through this, the servicing intervals can be adapted to the actual wear on the seal elements, so that servicing that is too early or too late can be prevented.

[0066] FIG. 4 shows the schematic structure of the scroll pump. Here, a scroll mechanism 60 is provided, as per FIG. 1. The scroll mechanism 60 is connected to a control device 62, to control the operation of the scroll mechanism 60. An intake valve 64 is connected to the inlet 12 of the scroll mechanism 60. A vacuum system or a receiving vessel 66 can be connected to the intake valve 64. Here, the intake valve 64 has a connection to the control device 62. Between the intake valve 64 and the scroll mechanism 60, the pressure at the inlet 12 of the scroll mechanism 60 is measured by means of a pressure sensor 68. Here, according to step S01, an end pressure is created by the scroll mechanism 60, and this end pressure is recorded by the pressure sensor 68. If this end pressure lies above a pre-set threshold value, a warning signal is emitted by a warning device 70, which indicates to the user that the scroll pump, and in particular the seal elements 42, must be serviced. Alternatively, the control device 62 can output a data signal by means of a communication device (not shown), which can be transmitted by means of a data interface 72 to a user interface of the user or to the manufacturer, for monitoring of the vacuum pump. Here, the scroll mechanism 60, intake valve 64, pressure sensor 68 and control device 62 are arranged within a common housing 74, through which a particularly compact construction is achieved.

[0067] According to FIG. 5, before the end pressure is produced by the scroll pump, in step S11 the intake valve 64 is closed. A gas load at the scroll mechanism 60 is thus prevented, and by means of the pressure sensor 68 the actual maximum achievable vacuum or the lowest pressure that can be achieved by the scroll mechanism 60 is recorded. On the basis of the end pressure that has been recorded in this way, a reliable conclusion can be drawn about the wear or condition of the seal elements 42 in the scroll mechanism 60, and servicing can be triggered if necessary.

[0068] Likewise during operation, via the pressure sensor 68 an operating pressure can be recorded which for example also records a gas load. If this operating pressure falls below a second pre-set threshold value, the rotational speed or output of the scroll mechanism 60 can be reduced by the control device 62, through which the scroll mechanism continues to produce an adequate vacuum according to the second threshold value, but in an energy-saving manner. The pressure sensor thus has two functions: firstly, to record the end pressure to determine the wear on the seal elements 42, and secondly, to record the operating pressure to save energy.

[0069] The intake valve 64 likewise has two functions: firstly, the intake valve 64 can be used as described above, in order to separate off a gas load from the receiving vessel 66, so that the end pressure that can be produced by the scroll mechanism 60 can be determined reliably. Furthermore, when the scroll pump is switched off or if there is a malfunction of the scroll mechanism 60, the intake valve 64 can be closed, so that return ventilation of the receiving vessel by the scroll pump is prevented.

[0070] Although elements have been shown or described as separate embodiments above, portions of each embodiment may be combined with all or part of other embodiments described above.

[0071] Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are described as example forms of implementing the claims.