METHOD OF OPERATING A PUMPING SYSTEM

• US 20100047080A1
• Filed: 01/23/2006
• Published: 02/25/2010
• Est. Priority Date: 02/02/2005
• Status: Active Grant

• Current Assignee: Edwards Limited (Atlas Copco AB)
• Original Assignee: BOC Group BV (Linde Plc)
• Inventors: Bruce, Simon Harold
• Granted Patent: US 9,062,684 B2
• Time in Patent Office: Days
• US Class Current: 417/45
• CPC Class Codes: F04B 2203/0201 Current
• CPC Class Codes: F04B 2203/0204 Frequency of the electric current
• CPC Class Codes: F04B 49/06 Control using electricity regulating by means of floats actuating electric switches F04B49/04
• CPC Class Codes: F04B 49/20 by changing the driving speed
• CPC Class Codes: F04C 18/12 of other than internal-axis type
• CPC Class Codes: F04C 18/16 with helical teeth, e.g. chevron-shaped, screw type for non-parallel axes of movement F04C18/48
• CPC Class Codes: F04C 2220/10 Vacuum
• CPC Class Codes: F04C 2220/12 Dry running
• CPC Class Codes: F04C 2240/403 with inverter for speed control
• CPC Class Codes: F04C 2270/08 Amplitude of electric current
• CPC Class Codes: F04C 2270/09 Electric current frequency
• CPC Class Codes: F04C 2270/18 Pressure
• CPC Class Codes: F04C 2270/19 Temperature
• CPC Class Codes: F04C 23/02 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04C 25/02 for producing high vacuum sealing arrangements F04C27/00; silencing F04C29/06
• CPC Class Codes: F04C 28/06 specially adapted for stopping, starting, idling or no-load operation
• CPC Class Codes: F04D 27/00 Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
• CPC Class Codes: F04D 27/004 by varying driving speed
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A pumping system for evacuating an enclosure comprises a pumping mechanism (30), a motor (32) for driving the pumping mechanism, and a controller (36) for controlling the motor. The controller sets a maximum value for a rotational frequency of the motor and a maximum value for a current in the motor, and, to optimise the performance of the pumping system, independently adjusts the maximum values during evacuation of the enclosure.

Claims

1. A pumping system comprising a pumping mechanism;

a motor for driving the pumping mechanism; and

a controller for controlling the motor, wherein the controller sets a maximum value for a rotational frequency of the motor and a maximum value for a current in the motor, and, to optimise the performance of the pumping system, adjusts said maximum values during operation of the pumping system.

2. The system according to claim 1 wherein the controller is configured to increase the maximum value for the current in the motor during operation of the pumping system at a relatively high pressure, and to increase the maximum value for the rotational frequency of the motor during operation of the pumping system at a relatively low pressure.

3. The system according to claim 1 comprising an inverter for supplying a variable frequency power to the motor, and wherein the controller is configured to adjust the amplitude and frequency of the power supplied to the motor during operation of the pumping system.

4. The system according to claim 1, wherein the controller is configured to receive input from at least one sensor for monitoring one or more states within the system, and to adjust at least one of said maximum values in dependence on the monitored states.

5. The system according to claim 4 wherein at least one sensor is configured to supply a signal indicative of a gas pressure within the pumping system, and wherein the controller is configured to adjust at least one of said maximum values in dependence on the received signal.

6. The system according to claim 5 wherein the controller is configured to adjust the maximum value for the current in the motor when the gas pressure is below a first predetermined value.

7. The system according to claim 6 wherein the first predetermined value is above 100 mbar.

8. The system according to claim 6 wherein the controller is configured to adjust the maximum value for the rotational frequency of the motor when the gas pressure is below a second predetermined value, the second predetermined value being lower than the first predetermined value.

9. The system according to claim 8 wherein the second predetermined value is between 1 mbar and 100 mbar.

10. The system according to claim 9 wherein the second predetermined value is between 10 mbar and 100 mbar.

11. The system according to claim 5 wherein two sensors are configured to detect respective different pressures within the pumping system, and the controller is configured to adjust at least one of the maximum values in dependence on a relationship between the detected pressures.

12. The system according to claim 5 wherein at least one sensor is configured to detect a pressure of a gas conveyed to the pumping mechanism.

13. The system according to claim 5 wherein at least one sensor is configured to detect a pressure of a gas exhaust from the pumping mechanism.

14. The system according to claim 1 further comprising a pressure relief valve in fluid communication with an exhaust from the pumping mechanism for selectively releasing gas compressed by the pumping mechanism to the atmosphere.

15. The system according to claim 5 further comprising a pressure relief valve in fluid communication with an exhaust from the pumping mechanism for selectively releasing gas compressed by the pumping mechanism to the atmosphere and wherein at least one sensor is configured to detect the position of the pressure relief valve, and the controller is configured to adjust at least one of said maximum values depending on the detected position.

16. The system according to claim 15 wherein the controller is configured to decrease the maximum value for the current in the motor when the pressure relief valve moves from an open position to a closed position.

17. The system according to claim 14 wherein the pressure relief valve is configured to move from the closed position to the open position when the pressure of gas compressed by the pumping mechanism is above atmospheric pressure.

18. The system according to claim 4 wherein at least one sensor is configured to supply a signal indicative of a temperature within the pumping system, and wherein the controller is configured to adjust at least one of said maximum values in dependence on the received signals.

19. The system according to claim 18 wherein the controller is configured to adjust the maximum value for the current in the motor when the temperature is above a first predetermined value.

20. The system according to claim 19 wherein the controller is configured to adjust the maximum value for the rotational frequency of the motor when the temperature is above a second predetermined value, the second predetermined value being different to the first predetermined value.

21. The system according to claim 18 wherein two sensors are configured to detect respective different temperatures within the pumping system, and the controller is configured to adjust at least one of the maximum values in dependence on a relationship between the detected temperatures.

22. The system according to claim 18 wherein at least one sensor is configured to supply a signal indicative of the temperature of gas exhaust from the pumping mechanism.

23. The system according to claim 18 wherein at least one sensor is configured to supply a signal indicative of the temperature of gas inlet to the pumping mechanism.

24. The system according to claim 18 wherein at least one sensor is configured to supply a signal indicative of the temperature of the pumping mechanism.

25. The system according to claim 1 wherein the controller is configured to the maximum values according to a predetermined timing relationship.

26. A method of controlling a pumping system comprising a pumping mechanism and a motor for driving the pumping mechanism, the method comprising the steps of setting a maximum value for a rotational frequency of the motor and a maximum value for a current in the motor, and, during operation of the pumping system, adjusting said maximum values to optimise the performance of the pumping system.

27. The method according to claim 26 wherein the maximum value for the current in the motor is increased during operation of the pumping system at a relatively high pressure, and the maximum value for the rotational frequency of the motor is increased during operation of the pumping system at a relatively low pressure.

28. The method according to claim 26 wherein the amplitude and frequency of a power supplied to the motor are adjusted during operation of the pumping system.

29. The method according to claim 26 wherein at least one of said maximum values is adjusted in dependence on one or more operational states of the system.

30. The method according to claim 29 wherein at least one of said maximum values is adjusted in dependence on at least one gas pressure within the pumping system.

31. The method according to claim 30 wherein the maximum value for the current in the motor is decreased when the gas pressure falls below a first predetermined value.

32. The method according to claim 31 wherein the first predetermined value is above 100 mbar.

33. The method according to claim 31 wherein the maximum value for the rotational frequency of the motor is increased when the gas pressure falls below a second predetermined value, the second predetermined value being lower than the first predetermined value.

34. The method according to claim 33 wherein the second predetermined value is between 1 mbar and 100 mbar.

35. The method according to claim 34 wherein the second predetermined value is between 10 mbar and 100 mbar.

36. The method according to claim 29 wherein at least one of said maximum values is adjusted in dependence on a relationship between two gas pressures within the pumping system.

37. The method according to claim 30 wherein at least one gas pressure is the pressure of a gas conveyed to the pumping mechanism.

38. The method according to claim 30 wherein at least one gas pressure is a pressure of a gas exhaust from the pumping mechanism.

39. The method according to claim 26 wherein the pumping system comprises a pressure relief valve downstream from the pumping mechanism, and at least one of the maximum values is adjusted depending on the position of the pressure relief valve.

40. The method according to claim 39 wherein the maximum value of the current in the motor is decreased when the pressure relief valve moves from an open position to a closed position.

41. The method according to claim 29 wherein at least one of said maximum values is adjusted in dependence on at least one temperature of the pumping system.

42. The method according to claim 41 wherein the maximum value for the current in the motor is decreased when at least one temperature is above a first predetermined value.

43. The method according to claim 42 wherein the maximum value for the rotational frequency of the motor is increased when at least one temperature is above a second predetermined value, the second predetermined value being different to the first predetermined value.

44. The method according to claim 41 wherein at least one of said maximum values is adjusted in dependence on a relationship between at least two temperatures of the pumping system.

45. The method according to claim 41 wherein at least one temperature is the temperature of gas exhaust from the pumping mechanism.

46. The method according to claim 41 wherein at least one temperature is the temperature of the pumping mechanism.

47. The method according to claim 26 wherein the maximum values are adjusted according to a predetermined timing relationship.