Pumping system and method of operation

• US 20090317261A1
• Filed: 04/13/2006
• Published: 12/24/2009
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: Edwards Limited (Atlas Copco AB)
• Original Assignee: Edwards Limited (Atlas Copco AB)
• Inventors: Bruce, Simon Harold
• Granted Patent: US 8,753,095 B2
• Time in Patent Office: Days
• US Class Current: 417/32
• CPC Class Codes: F04C 18/12 of other than internal-axis type
• CPC Class Codes: F04C 2270/07 Electric current
• CPC Class Codes: F04C 2270/09 Electric current frequency
• CPC Class Codes: F04C 2270/125 Controlled or regulated
• CPC Class Codes: F04C 2270/175 Controlled or regulated
• CPC Class Codes: F04C 2270/19 Temperature
• CPC Class Codes: F04C 28/08 characterised by varying the rotational speed
• CPC Class Codes: F04C 28/28 Safety arrangements; Monitoring
• CPC Class Codes: F04D 15/0077 Safety measures F04D15/02 takes precedence
• CPC Class Codes: F04D 15/0263 the condition being temperature, ingress of humidity or leakage
• CPC Class Codes: F04D 19/042 Turbomolecular vacuum pumps

Abstract

A pumping system comprises a pumping mechanism, a motor for driving the pumping mechanism, means for supplying power of a variable frequency to the motor, control means for setting a maximum value for a current in the motor, and means for supplying to the control means data indicative of the temperature of gas exhaust from the pumping mechanism and a temperature of the stator of the pumping mechanism, wherein the control means is configured to use the received data to adjust the maximum value during operation of the pumping system.

Claims

1. A pumping system comprising:

a pumping mechanism;

a motor for driving the pumping mechanism;

means for supplying power of a variable frequency to the motor;

control means for setting maximum values for a current and frequency in the motor;

means for supplying to the control means data indicative of the temperature of a gas exhaust from the pumping mechanism and a temperature of the stator of the pumping mechanism, and wherein the control means is configured to use the received data to adjust at least one of said maximum values during operation of the pumping system.

2. The system according to claim 1 wherein the control means is configured to adjust the amplitude and frequency of the power supplied to the motor by the drive means during operation of the pumping system.

3. The system according to claim 1 wherein the data supply means comprises a first temperature sensor for supplying a signal indicative of the temperature of gas exhaust from the pumping mechanism, and a second temperature sensor for supplying a signal indicative of the temperature of a selected part of the stator.

4. The system according to claim 3 wherein the first temperature sensor is located proximate an exhaust of the pumping mechanism.

5. The system according to claim 3 wherein the control means is configured to adjust at least one of said maximum values in dependence at least on the variation with time of the signal received from the first temperature sensor.

6. The system according to claim 3 wherein the second temperature sensor is located on the external surface of the stator of the pumping mechanism.

7. The system according to claim 6 wherein the second temperature sensor is located proximate an inlet of the pumping mechanism.

8. The system according to claim 3 wherein the control means is configured to adjust at least one of said maximum values in dependence on at least the variation with time of the signal received from the second temperature sensor.

9. The system according to claim 3 comprising a plurality of said second temperature sensors each located at different positions on the external surface of the stator of the pumping mechanism.

10. The system according to claim 3 wherein a vibration sensor is configured to supply a signal indicative of vibration of the pumping mechanism, and wherein the control means is configured to use the signal received from the vibration sensor to adjust at least one said maximum values.

11. The system according to claim 3 wherein the control means is configured to adjust at least one of said maximum values according to a predetermined relationship between the monitored temperatures.

12. The system according to claim 1 further comprising a pressure sensor for supplying a signal indicative of the pressure of gas entering the pumping mechanism, and wherein the control means is configured to use the signal received from the pressure sensor to adjust at least one of said maximum values.

13. The system according to claim 1 wherein the control means comprises a first controller for setting said maximum values, and a second controller for receiving said data and instructing the first controller to adjust at least one of said maximum values in response thereto.

14. A method of controlling a pumping system comprising a pumping mechanism, a motor for driving the pumping mechanism and a variable frequency drive unit for supplying power to the motor, the method comprising the steps of:

setting maximum values for a current and frequency in the motor;

receiving data indicative of the temperature of gas exhaust from the pumping mechanism and a temperature of the stator of the pumping mechanism; and

using the received data to adjust at least one of said maximum values during operation of the pumping system.

15. The method according to claim 14 further comprising the step of adjusting the amplitude and frequency of a power supplied to the motor are adjusted during operation of the pumping system.

16. The method according to claim 15 wherein the step of using the received data adjusts at least one of said maximum values in dependence on received signals indicative of the temperature of gas exhaust from the pumping mechanism and the temperature of a selected part of the stator.

17. The method according to claim 16 wherein the step of using the received data adjusts at least one of said maximum values in dependence on the variation with time of the signal indicative of the temperature of gas exhaust from the pumping mechanism.

18. The method according to claim 16 wherein the signal indicative of the temperature of the stator is obtained from a sensor located on an external surface of the stator of the pumping mechanism.

19. The method according to claim 18 wherein at least one of said maximum values is adjusted in dependence on at least the variation with time of the signal received from the sensor.

20. The method according to claim 14 wherein at least one of said maximum values is adjusted using a signal indicative of vibration of the pumping mechanism during use of the pumping system.

21. The method according to claim 14 wherein at least one of said maximum values is adjusted using a signal indicative of the pressure of gas entering the pumping mechanism.