Method of operating a pumping system

• US 9,062,684 B2
• Filed: 01/23/2006
• Issued: 06/23/2015
• Est. Priority Date: 02/02/2005
• Status: Active Grant

• Current Assignee: Edwards Limited (Atlas Copco AB)
• Original Assignee: Edwards Limited (Atlas Copco AB)
• Inventors: Bruce, Simon Harold
• Primary Examiner(s): Kramer, Devon
• Assistant Examiner(s): Hamo, Patrick
• Application Number:
  US11/883,616
• Publication Number:
  US 20100047080A1
• Time in Patent Office: 3,438 Days
• Field of Search: 417/44.1, 417/44.2, 417/44.11, 417/45, 417/53
• US Class Current: 1/1
• 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 optimize 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;

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

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,

wherein at least one sensor is configured to detect the position of the pressure relief valve, the position of the pressure relief valve being indicative of a gas pressure within the pumping system, and

wherein the controller is configured to adjust at least one of the maximum values depending on an indication of the detected position from the at least one sensor.

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

3. The system according to claim 1, 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.

4. The system according to claim 3, wherein the first predetermined value is above 100 mbar.

5. The system according to claim 3, wherein the controller is configured to increase 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.

6. The system according to claim 5, wherein the second predetermined value is between 1 mbar and 100 mbar.

7. The system according to claim 6, wherein the second predetermined value is between 10 mbar and 100 mbar.

8. The system according to claim 1, 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.

9. The system according to claim 1, 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.

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

11. 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 from a normal continuous rating of the motor temporarily to a value higher than the normal continuous rating of the motor.