Method for operating a scroll vacuum pump

Abstract

A method for operating and, in particular, monitoring a scroll pump, the method comprising the steps of generating a vacuum by the scroll pump, determining a pressure in the scroll pump, comparing the recorded pressure with a preset threshold, and issuing a warning signal if the recorded pressure exceeds the preset threshold. The present invention further relates to a scroll pump for carrying out the method.

Description

Technical Field

[0001] The present invention relates to a method of operating a scroll pump, in particular monitoring a scroll pump, and to such a scroll pump.

Background Art

[0002] A well-known scroll pump comprises a housing having an inlet and an outlet. In this case, a first scroll element is arranged within the housing and coupled to the housing, so the first scroll element functions as a stator. In this case, the first scroll element has a base and a substantially spiral wall extending from the base. Further, a second scroll element arranged within the housing is driven by an electric motor to orbit around the first scroll element. In this case, likewise, the second scroll element has a base and a substantially spiral wall extending from the base. In this case, the wall of the first scroll element and the wall of the second scroll element are nested within each other, and at least partially individual pump chambers are created. Due to the relative movement of the second scroll element with respect to the first scroll element, the gaseous medium is transferred from the inlet to the outlet.

[0003] In order to design the pump chamber as airtight as possible, a seal is arranged between the end of the spiral wall on the side opposite the base of the first scroll element and the base of the second scroll element. Similarly, a seal is arranged between the end of the spiral wall on the side opposite the base of the second scroll element and the base of the first scroll element. This seal wears due to the relative movement between the first scroll element and the second scroll element.

[0004] Therefore, the airtightness of the pump chamber decreases over the useful life, and it is necessary to replace each seal during maintenance of the scroll pump.

[0005] In the case of a general scroll pump, such maintenance is assumed after a preset operating time. In this case, the operating time is set by the manufacturer and does not depend on the actual operating parameters of the scroll pump. Therefore, the preset operating time until the next maintenance is independent of the operating load, the gas being conveyed, deviations in manufacturing quality, etc., all of which affect seal wear and rupture. Therefore, for example, when wear progresses, seal replacement often becomes delayed, so that the performance of the scroll pump itself cannot be fully exerted. However, this has an adverse effect on the application where the scroll pump supplies a vacuum. Alternatively, when wear is low, seal replacement is too early, resulting in a short maintenance interval and an increase in cost.

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a method for ensuring optimal performance and reducing maintenance costs, as well as a scroll pump.

Means for Solving the Problems

[0007] This problem is solved by a method of operating the scroll pump according to claim 1 or 2, and the scroll pump according to claim 10 .

[0008] A method for operating a scroll pump according to the present invention, particularly for monitoring the scroll pump, comprises a) generating a vacuum by the scroll pump; b) measuring the pressure of the scroll pump; c) comparing the recorded pressure with a preset threshold value; d) issuing a warning signal when the recorded pressure exceeds the preset threshold value; and Note that the recorded pressure is the end pressure, and the warning signal corresponds to the remaining operating time predicted from the reached end pressure. .

[0009] In this case, the recorded pressure is , end the end pressure, that is, the maximum vacuum or the minimum pressure that the scroll pump can produce. Alternatively, it is also possible to set the pressure recorded under the same pump conditions so that there is a comparability between the pressure determined at the first point in time and the pressure determined at a later point in time. Determining the pressure of the scroll pump can include recording the pressure of the scroll pump or determining the recorded pressure of the scroll pump.

[0010] In this case, the preset threshold value can be set to the possible pressure of the scroll pump that can be achieved, especially the specification of the end pressure, or can be determined, for example, according to the user's requirements. In this case, the threshold value can be the same for multiple scroll pumps or can be set according to the type or structure of the scroll pump. When the scroll pump reaches an end pressure exceeding the preset threshold value, that is, when it is greater than the preset threshold value and the appropriate vacuum is not generated by the scroll pump, a warning signal is issued. Based on the warning signal, the user understands that maintenance is required, especially that the seal of the scroll pump needs to be replaced. Therefore, since the replacement or maintenance of the scroll pump is basically guided by the actual end pressure of the scroll pump affected by seal wear, the maintenance interval is independent of the preset operating time, especially considering the operating load, the gas transported, and the deviation of the manufacturing quality of the scroll pump. Therefore, for example, when the wear is small, the maintenance interval can be significantly longer than the currently specified operating time. This can extend the maintenance interval and reduce costs. However, if wear progresses due to the operation of the scroll pump and the scroll pump reaches the required end pressure before the preset operating time, resulting in a decrease in the performance of the scroll pump, in order to always guarantee the optimal performance of the scroll pump, the maintenance of the scroll pump is started early.

[0011] Preferably, the terminal pressure is determined at the inlet. The flow characteristics within the scroll mechanism are irrelevant here, and the terminal pressure can be directly recorded. Alternatively or additionally, the pressure is not directly recorded at the inlet but is recorded by a pressure sensor within the scroll mechanism, and the terminal pressure or the wear of the seal is inferred based on the recorded pressure.

[0012] Preferably, when a preset first threshold value is exceeded, a first warning signal is generated, and when a preset second threshold value is exceeded, a second warning signal is generated. In this case, in particular, the first threshold value is lower than the second threshold value. In this way, the state of the seal can be shown to the user. In particular, the first threshold value and / or the second threshold value can be associated with the quality of the seal. Thus, for example, when the first warning signal occurs exceeding the first threshold value, the quality of the seal has deteriorated but further operation is possible. Corresponding maintenance can be carried out. When the second threshold value is exceeded, the seal quality has deteriorated to cause performance failure, and reliable operation is no longer possible and maintenance is required. In particular, additional threshold values can be assumed, preferably, a continuous comparison between the achieved terminal pressure and the preset terminal pressure, and, for example, a continuous percentage display of the seal quality is possible.

[0013] According to the present invention The remaining operating time is predicted and displayed from the achieved terminal pressure. In this case, the remaining operating time can be calculated based on the load of the vacuum pump in the previous period, the wear of the seal in the previous period, the required operating pressure, the operating temperature, etc. Thus, maintenance can be planned early and the stoppage of the vacuum pump can be prevented.

[0014] Preferably, before the terminal pressure is generated, the intake valve disposed at the inlet of the scroll pump is closed. In this case, the terminal pressure is measured or recorded in front of the intake valve starting from the scroll pump. In particular, during operation, it is not immediately clear whether the pressure reached is the terminal pressure, i.e., the maximum vacuum that can be generated or the minimum pressure that can be achieved, or whether the pressure reached is the operating pressure associated with the gas load. By closing the intake valve, the scroll pump is clearly separated from the gas load, and currently, the pressure being generated and recorded corresponds to the terminal pressure of the scroll pump in any case. This ensures that the correct terminal pressure is always recorded regardless of the presence or absence of a possible gas load.

[0015] The warning signal can preferably be an optical signal and / or an acoustic signal and / or a data signal that can be sent by a communication device. In this case, the optical or acoustic warning signal can be generated directly by the scroll pump or by a warning device on the scroll pump. Alternatively, the optical signal and / or the acoustic signal can be generated by an additional device such as an external control device. In particular, the data signal is transferred to the user interface by the communication device for the control of the scroll pump by the user. Alternatively or additionally, the data signal is transferred to the manufacturer for the automatic activation of the maintenance of the scroll pump.

[0016] Preferably, the above method is executed at preset time intervals. In particular, the preset time interval can be made shorter as the terminal pressure approaches a preset threshold (without exceeding the preset threshold). Alternatively, since the above method is activated based on a user input or an input signal by the user, the monitoring of the scroll pump can be initiated by the user.

[0017] Preferably, during operation, the operating pressure is measured at the inlet of the scroll pump, and when the measured operating pressure falls below a second threshold value, the rotational speed of the scroll pump is reduced. This can be a continuous adjustment of the rotational speed according to the operating pressure. Alternatively, the rotational speed of the scroll pump can also be gradually reduced until the operating pressure at the inlet of the scroll pump exceeds the second threshold value. In particular, since a pressure sensor for recording the reached terminal pressure is assumed to be provided at the inlet of the scroll pump, this pressure sensor can be used during the operation of the scroll pump to record, for example, the operating pressure generated along with the gas load. During normal operation, the gas load at the pump inlet is approximately constant, and the recorded operating pressure generated along with the gas load will also be constant. The same applies to the circulation operation, reaching approximately the same pressure after a specific fixed time and being used as the operating pressure. When the operating pressure falls below the second threshold value, the output of the scroll pump can be reduced by reducing the rotational speed, thereby saving energy and preventing wear of the seal. Therefore, efficient pressure control can be performed, the seal life can be extended, the maintenance cost can be reduced, and optimal performance can be guaranteed. In particular, in this case, the first threshold value is larger than the second threshold value.

[0018] Preferably, the operating pressure can be used as the recorded pressure, and the comparison between the operating pressure and the first threshold value can be used to issue a warning signal.

[0019] Preferably, the intake valve is closed when the scroll pump is turned off. Alternatively or additionally, the intake valve is closed in case of a failure of the scroll pump. Therefore, the provided intake valve is for the purpose of monitoring the scroll pump during the generation of the terminal pressure, and further, the intake valve can prevent the connected vacuum system from being reventilated when the scroll pump stops or when the scroll pump fails.

[0020] Preferably, the gas load is recorded at the inlet. If there is a gas load and the pressure is at a pre-set reference value, which should not be the end pressure, then the pressure is not measured, or the gas load recorded when determining the end pressure is taken into account.

[0021] The present invention further relates to a method for operating, in particular monitoring, a scroll pump, the method comprising: a) generating a vacuum by means of the scroll pump; b) recording a first pressure and a second pressure of the scroll pump; c) comparing the pressure difference between the first pressure and the second pressure with a pre-set threshold value; d) emitting a warning signal if the pressure difference falls below the pre-set threshold value. comprising Note that the end pressure is determined from the pressure difference, and the warning signal corresponds to the remaining operating time predicted from the reached end pressure. .

[0022] In this case, the first pressure and the second pressure are recorded at different positions within the scroll pump. Thus, for example, the first pressure can be directly recorded at the inlet, and the second pressure can be recorded within the scroll mechanism. Alternatively, the first pressure and the second pressure are recorded at different positions along the scroll mechanism. Based on the pressure difference, seal wear can be inferred. Since the recording positions of the first pressure and the second pressure do not change, the change in the pressure difference is due to seal wear. Here, when the sealing effect of the seal decreases, the pressure difference between two points along the flow path of the scroll pump changes proportionally. Therefore, based on this pressure difference, the state of the seal of the scroll mechanism can be inferred. When the pressure difference falls below a preset threshold value, a warning signal is issued. In this case, the threshold value can be made common for a plurality of scroll pumps or set according to the type or structure of the scroll pump. Based on the warning signal, the user understands that maintenance is required, particularly that the seal of the scroll pump needs to be replaced. Since the replacement or maintenance of the scroll pump is basically guided by the actual terminal pressure of the scroll pump that affects seal wear, the maintenance interval is independent of the preset operating time, particularly considering the operating load, the gas being conveyed, and the deviation in the manufacturing quality of the scroll pump. Thus, for example, in the case of wear, the maintenance interval can be made significantly longer than the currently specified operating time.

[0023] Thereby, the maintenance interval can be lengthened to reduce costs. However, if wear progresses due to the operation of the scroll pump and the scroll pump reaches the required terminal pressure before the preset operating time, resulting in a decrease in the performance of the scroll pump, in order to always guarantee the optimal performance of the scroll pump, the maintenance of the scroll pump is started early.

[0024] Furthermore, the present method is further developed based on the above-described features. In particular, the features of the two methods described above can be freely combined with each other. For example, the first pressure and the second pressure can always be recorded during operation. For example, the first pressure is directly recorded at the inlet. The state of the seal can be inferred from the pressure difference. However, when there is a gas load, the first pressure can be applied as the terminal pressure and compared with a threshold value. Alternatively or additionally, the terminal pressure can be inferred from the determined pressure difference and the determined terminal pressure can be compared with the threshold value. In this way, the results of the two methods can be combined with each other and can be used to achieve an improvement in the prediction accuracy regarding seal wear.

[0025] Furthermore, the present invention relates to a scroll pump provided with a housing having an inlet and an outlet. In particular, a first scroll element is disposed within and coupled to the housing, and the first scroll element is adapted to function as a stator. In this case, the first scroll element has a base and a substantially spiral wall extending from the base. Alternatively, a second scroll element disposed within the housing is driven by an electric motor to orbit around the first scroll element. Similarly, the second scroll element has a base and a substantially spiral wall extending from the base. In this case, the wall of the first scroll element and the wall of the second scroll element are nested within each other, and individual pump chambers are created at least in part.

[0026] Due to the relative movement of the second scroll element with respect to the first scroll element, the gaseous medium is transferred from the inlet to the outlet. In order to design the pump chamber to be as airtight as possible, a seal is disposed between the end of the spiral wall on the side opposite to the base of the first scroll element and the base of the second scroll element. Similarly, a seal is disposed between the end of the spiral wall on the side opposite to the base of the second scroll element and the base of the first scroll element.

[0027] According to the present invention, the control device is connected to a scroll pump to control the scroll pump. Further, at least one pressure sensor is envisaged to record the pressure of the scroll pump. The pressure sensor is connected to the control device. In this case, the control device is designed to execute the method described above.

[0028] Preferably, the pressure sensor is arranged at the inlet of the scroll pump to directly record the inlet pressure, in particular the end pressure, when there is no gas load. Alternatively, the recorded pressure is, in particular, the operating pressure associated with the gas load.

[0029] Preferably, the pressure sensor is arranged in the scroll mechanism formed by the first scroll element and the second scroll element. In this case, a pressure greater than the end pressure is measured instead of the actual end pressure. However, appropriate conclusions can be drawn regarding the end pressure, or the wear of the seal can be similarly inferred from the pressure recorded in the scroll mechanism. Thereby, the design of the pressure sensor can be made simpler and more economical.

[0030] Preferably, a first pressure sensor and a second pressure sensor are provided. The first pressure sensor and the second pressure sensor are arranged in the scroll mechanism and connected to the control device. Alternatively, the first pressure sensor is arranged at the inlet of the scroll pump and the second pressure sensor is arranged in the scroll mechanism. Therefore, two pressures are recorded. In particular, the state of the seal can be inferred from the pressure difference between the first pressure sensor and the second pressure sensor.

[0031] Preferably, an intake valve is arranged at the inlet of the scroll pump. The intake valve is connected to the control device, and the control device is designed to close the intake valve to determine the end pressure. In addition, the intake valve can be closed by the control device when the switch of the scroll pump is turned off and / or when the scroll pump fails to prevent the connected vacuum system from being reventilated.

[0032] Preferably, the control device and / or the pressure sensor and / or the intake valve are arranged inside the housing of the scroll pump. Thereby, a simple and compact structure of the scroll pump is realized. At the same time, it is ensured that both the pressure sensor and the intake valve are present for implementing a method of monitoring the scroll pump, and there is no need for the user to prepare them separately.

[0033] Preferably, the scroll pump has a communication device for sending the operating pressure recorded by the pressure sensor and / or the recorded end pressure and / or the generated warning signal. In this case, the operating pressure, the end pressure, and / or the generated warning signal can be sent to the user interface so that the user can understand the recorded operating pressure, the recorded end pressure, and / or the generated warning signal. Alternatively or additionally, this information can be sent to the manufacturer of the vacuum pump for monitoring the scroll pump.

[0034] Alternatively or additionally, the scroll pump is provided with a warning device for emitting an optical and / or acoustic warning when the reached end pressure exceeds a preset threshold value.

[0035] Hereinafter, the present invention will be further described based on preferred embodiments with reference to the accompanying drawings.

Brief Description of the Drawings

[0036]

Figure 1A

Figure 1B

Figure 2

Figure 3

Figure 4

Figure 5

Best Mode for Carrying Out the Invention

[0037] FIG. 1A shows a cross-section of a scroll pump having a housing that defines an inlet 12 and an outlet 14. A first scroll element 16 that functions as a stator is coupled to the housing. Further, a second scroll element 18 is disposed within the housing 10, and the second scroll element 18 orbits around the first scroll element 16. In this case, the second scroll element 18 is coupled to a shaft 20 that is driven by an electric motor 22, and the second scroll element 18 is adapted to rotate around a common axis 34.

[0038] The first scroll element 16 has a base 26 and a first wall 28 that extends from the base 26 and is basically spiral.

[0039] Furthermore, the second scroll element 18 has a second base 30 and a second wall 32 that extends from the second base 30 and engages or conforms to the first wall 28. The first wall 28 and the second wall 32 define at least a part of the pump chamber 33, and when the second scroll element 18 moves, the gaseous medium is adapted to be conveyed from the inlet 12 to the outlet 14.

[0040] FIG. 2 shows an example of a detailed view of the first wall 28. In this case, the first wall 28 of the first scroll element 16 faces the second base 30 of the second scroll element 18 and has a first end 40 that is disposed on the opposite side of the first base 26 of the first scroll element 16. A seal element 42 that contacts the second base 30 of the second scroll element 18 is disposed at the first end 40 of the first wall 28. In this case, the seal element extends along at least a part, preferably the entire length, of the basically spiral first wall 28. Similarly, the seal element is provided at the end of the spiral wall of the second scroll element 18, which contacts the base 26.

[0041] Due to the contact between the seal element 42 and the surface 44 of the second scroll element 18 located on the opposite side, the seal element 42 wears out due to the relative movement between the first scroll element 16 and the second scroll element 18. This wear reduces the sealing effect of the seal element 42, thereby reducing the airtightness of each pump chamber 33 and similarly reducing the output of the scroll pump.

[0042] Figure 3 is a flowchart of a method according to the present invention for the operation and / or monitoring of a scroll pump, a) a step of generating an end pressure by a scroll pump, S01; b) a step of recording the end pressure achieved at the inlet of the scroll pump, S02; c) a step of comparing the achieved end pressure with a preset threshold value, S03; d) a step of emitting a warning signal when the achieved end pressure exceeds the preset threshold value, S04; is included.

[0043] Thus, based on the achieved end pressure, it is possible to determine whether it is necessary to replace the seal element 42. Thereby, the maintenance interval can be adapted to the actual wear of the seal element, and premature or overdue maintenance can be prevented.

[0044] Figure 4 shows the schematic structure of the scroll pump. In this case, a scroll mechanism 60 as shown in Figure 1 is provided. The scroll mechanism 60 is connected to a control device 62 for controlling the operation of the scroll mechanism 60. An intake valve 64 is connected to the inlet 12 of the scroll mechanism 60. The intake valve 64 can be connected to a vacuum device or a receiving container 66. In this case, the intake valve 64 has a connection part with 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 a pressure sensor 68. In this case, according to step S01, the scroll mechanism 60 brings about an end pressure, and this end pressure is recorded by the pressure sensor 68. When this end pressure exceeds a preset threshold value, a warning signal is issued by a warning device 70, indicating to the user that the scroll pump, particularly the seal element 42, needs maintenance. Alternatively, the control device 62 can output a data signal by a communication device (not shown), and this data signal can be sent by a data interface 72 to the user interface of the user or the manufacturer for monitoring the vacuum pump. In this case, the scroll mechanism 60, the intake valve 64, the pressure sensor 68, and the control device 62 are arranged in a common housing 74, thereby achieving a particularly compact structure.

[0045] According to Figure 5, before the scroll pump generates an end pressure, in step S11, the intake valve 64 is closed. Thus, the gas load in the scroll mechanism 60 is prevented, and the maximum vacuum actually achievable or the minimum pressure achievable by the scroll mechanism 60 is recorded by the pressure sensor 68. Based on the end pressure recorded in this way, a reliable conclusion can be drawn regarding the wear or condition of the seal element 42 of the scroll mechanism 60, and maintenance can be started if necessary.

[0046] Similarly, during operation, the pressure sensor 68 can record the operating pressure, which also records, for example, the gas load. If this operating pressure falls below a preset second threshold value, the rotational speed or output of the scroll mechanism 60 can be reduced by the control device 62, whereby the scroll mechanism continues to generate an appropriate vacuum according to the second threshold value, which is an energy-saving mode. Therefore, the pressure sensor has two functions. The first function is to record the terminal pressure to determine the wear of the seal element 42, and the second function is to record the operating pressure for energy conservation.

[0047] Similarly, the intake valve 64 has two functions. First, the intake valve 64 can be used as described above to separate the gas load from the receiving container 66 and is capable of accurately determining the terminal pressure that can be generated by the scroll mechanism 60. Further, when the scroll pump is turned off or a failure occurs in the scroll mechanism 60, the intake valve 64 can be closed to prevent the return ventilation of the receiving container by the scroll pump.

Description of Symbols

[0048] 10 Housing 12 Inlet 14 Outlet 60 Scroll mechanism 62 Control device 68 Pressure sensor

Claims

1. A method for operating a scroll pump to monitor wear of a seal of the scroll pump, comprising: a) generating a vacuum by the scroll pump (S01); b) measuring and recording the pressure of the scroll pump (S02); c) comparing the recorded pressure with a preset threshold value (S03); d) when the recorded pressure exceeds the preset threshold value, issuing a warning signal (S04); and the recorded pressure is an end pressure that is the maximum vacuum or the minimum pressure that can be generated by the scroll pump, and the warning signal is issued based on the remaining operating time of the seal predicted from the reached end pressure.

2. A method for operating a scroll pump to monitor wear of a seal of the scroll pump, comprising: a) generating a vacuum by the scroll pump; b) recording a first pressure and a second pressure of the scroll pump; c) comparing the pressure difference between the first pressure and the second pressure with a preset threshold value; d) when the pressure difference is below the preset threshold value, issuing a warning signal; and the end pressure that is the maximum vacuum or the minimum pressure that can be generated by the scroll pump is determined from the pressure difference, and the warning signal is issued based on the remaining operating time of the seal predicted from the reached end pressure.

3. The method according to claim 1 or 2, wherein the pressure at the inlet (12) of the scroll pump and / or in the scroll mechanism (60) of the scroll pump is recorded.

4. The method according to claim 1, wherein before the generation of the terminal pressure, a step (S11) of closing an intake valve disposed at an inlet of the scroll pump is executed.

5. The method according to any one of claims 1 to 4, wherein the warning signal is an optical signal and / or an acoustic signal and / or a data signal that can be sent by a communication device.

6. The method according to any one of claims 1 to 5, wherein the method is implemented based on a preset time interval or an input signal.

7. The method according to any one of claims 1 to 6, wherein during operation, an operating pressure is measured at an inlet (12) of the scroll pump, and when the measured operating pressure is lower than a second threshold value, a rotational speed of the scroll pump is reduced.

8. The method according to claim 4, wherein when the scroll pump is turned off and / or when the scroll pump fails, the intake valve (64) is closed.

9. The method according to any one of claims 1 to 8, wherein when a gas load exists, the gas load is recorded and the terminal pressure or the pressure difference is not recorded.

10. A scroll pump, comprising: a housing (10) having an inlet (12) and an outlet (14); a control device (62) connected to the scroll pump; at least one pressure sensor (68) disposed in the scroll pump for recording a pressure of the scroll pump and connected to the control device (62); and the control device (62) is designed to implement the method according to any one of claims 1 to 9.

11. The scroll pump according to claim 10, wherein the pressure sensor (68) is disposed at the inlet (12) of the scroll pump.

12. The scroll pump according to claim 10 or 11, wherein the recorded pressure is an operating pressure.

13. The scroll pump according to any one of claims 10 to 12, wherein the pressure sensor (68) is disposed within the scroll mechanism (60) of the scroll pump.

14. The scroll pump according to any one of claims 10 to 13, wherein at least two pressure sensors (68) are provided to record a first pressure and a second pressure, and the recorded pressure is determined from a pressure difference between the first pressure and the second pressure.

15. An intake valve (64) is disposed at the inlet (12), the intake valve (64) is connected to the control device (62), and the control device (62) is designed to close the intake valve (64) to determine the terminal pressure. The scroll pump according to any one of claims 10 to 14.

16. The scroll pump according to claim 15, wherein the control device (62) and / or the pressure sensor (68) and / or the intake valve (64) are disposed within the housing (10) of the scroll pump.

17. The scroll pump according to any one of claims 10 to 16, further comprising a communication device for sending the operating pressure and / or the recorded terminal pressure and / or the generated warning signal recorded by the pressure sensor (68).

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