Helium management control system

• US 7,788,942 B2
• Filed: 10/31/2006
• Issued: 09/07/2010
• Est. Priority Date: 07/20/2001
• Status: Active Grant

• Current Assignee: Edwards Vacuum, LLC (Atlas Copco AB)
• Original Assignee: Brooks Automation Incorporated (Azenta, Inc.)
• Inventors: Chopy, Joseph Jr., Bartlett, Allen J., Andeen, Bruce, Dresens, Paul E., Than, Y. Roberto, Ash, Gary S.
• Primary Examiner(s): JIANG, CHEN WEN
• Application Number:
  US11/590,673
• Publication Number:
  US 20070107448A1
• Time in Patent Office: 1,407 Days
• Field of Search: 621/49, 62/555, 62/6, 622/92, 62/77, 626/08, 621/75, 621/85
• US Class Current: 62/292
• CPC Class Codes: B01D 8/00 Cold traps; Cold baffles pumps for evacuating by condensing or freezing F04B37/08
• CPC Class Codes: F04B 37/08 by condensing or freezing, e.g. cryogenic pumps
• CPC Class Codes: F17D 1/04 for distribution of gas
• CPC Class Codes: F17D 3/01 for controlling, signalling, or supervising the conveyance of a product
• CPC Class Codes: F17D 3/18 for measuring the quantity of conveyed product measuring volume or volume flow, in general G01F
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 2110/50 Air quality properties
• CPC Class Codes: F25B 2309/001 with a linear configuration or a linear motor
• CPC Class Codes: F25B 2309/002 with parallel working cold producing expansion devices in one circuit
• CPC Class Codes: F25B 2309/1428 Control of a Stirling refrigeration machine
• CPC Class Codes: F25B 2345/001 Charging refrigerant to a cycle
• CPC Class Codes: F25B 2345/003 Control issues for charging or collecting refrigerant to or from a cycle
• CPC Class Codes: F25B 45/00 Arrangements for charging or discharging refrigerant
• CPC Class Codes: F25B 9/002 characterised by the refrigerant
• CPC Class Codes: F25B 9/14 characterised by the cycle used, e.g. Stirling cycle
• CPC Class Codes: F25J 1/0007 Helium

Abstract

A helium management control system for controlling the helium refrigerant supply from a common manifold supplies a plurality of cryogenic refrigerators with an appropriate helium supply. The system employs a plurality of sensors to monitor and regulate the overall refrigerant supply to deliver an appropriate refrigerant supply to each of the cryogenic refrigerators depending on the computed aggregate cooling demand of all of the cryogenic refrigerators. An appropriate supply of helium is distributed to each cryopump by sensing excess and sparse helium refrigerant and redistributing refrigerant accordingly. If the total refrigeration supply exceeds the total refrigerant demand, or consumption, excess refrigerant is directed to cryogenic refrigerators which can utilize the excess helium to complete a current cooling function more quickly. Similarly, if the total refrigeration demand exceeds the total refrigeration supply, the refrigerant supply to some or all of the cryogenic refrigerators will be reduced accordingly so that detrimental or slowing effects are minimized based upon the current cooling function.

Claims

1. A system for controlling distribution of a refrigerant among a plurality of refrigerators comprising:

a compressor bank including at least one compressor, the compressor including a high pressure supply line and a low pressure exhaust line, the compressor bank capable of supplying a refrigerant;

a plurality of refrigerators coupled to the compressor bank, the refrigerators adapted to consume refrigerant;

an electronic controller capable of allocating the refrigerant to the refrigerators, the allocation of the refrigerant in response to operating parameters associated with the refrigerators, the operating parameters include a pressure differential based on a difference in pressure between the high pressure supply line and the low pressure exhaust line;

wherein the electronic controller reallocates the refrigerant in response to determining and redetermining the pressure differential.

2. The system of claim 1 wherein the determined and redetermined pressure differential is substantially the same for all compressors connected to the compressor bank.

3. The system of claim 1 wherein the determined and redetermined pressure differential is substantially the same for the compressor bank and the refrigerators.

4. The system of claim 1 wherein the refrigerant is helium.

5. The system of claim 1 wherein the allocating and reallocating of the refrigerant comprises varying the supply of refrigerant to the refrigerators depending on the operating parameters.

6. The system of claim 1 wherein the refrigerators are included in cryopumps.

7. A method for controlling distribution of refrigerant among a plurality of refrigerators including:

a compressor bank including at least one compressor, the compressor including a high pressure supply line and a low pressure exhaust line, the compressor bank capable of supplying a refrigerant;

a plurality of refrigerators coupled to the compressor bank, the refrigerators adapted to consume the refrigerant, the method comprising;

determining operating parameters associated with the refrigerators, the operating parameters include a pressure differential determined from a difference in pressure between the high pressure supply line and the low pressure exhaust line;

allocating the refrigerant to the refrigerators based on the operating parameters, the operating parameters include the pressure differential; and

reallocating the refrigerant to the refrigerators in response to changes in the operating parameters, changes in the operating parameters include changes in the pressure differential.

8. The method of claim 7 wherein reallocating the refrigerant in response to changes to the operating parameters further includes:

comparing the pressure differential to a differential pressure setpoint;

determining that an under pressure condition exists; and

in response to the under pressure condition, reallocating the refrigerant.

9. The method of claim 7 wherein reallocating the refrigerant in response to changes to the operating parameters further includes:

comparing the pressure differential to a differential pressure setpoint;

determining that an over pressure condition exists; and

in response to the over pressure condition, reallocating the refrigerant.

10. The method of claim 7 wherein the refrigerant is helium.

11. The method of claim 7 wherein the allocating and reallocating of the refrigerant comprises varying the supply of refrigerant to the refrigerators depending on the operating parameters.

12. The method of claim 11 wherein varying the supply of refrigerant further includes:

comparing the pressure differential to a differential pressure setpoint;

determining that an over pressure condition exists; and

in response to over pressure condition, reducing the supply of helium.

13. The method of claim 11 wherein varying the supply of refrigerant further includes:

comparing the pressure differential to a differential pressure setpoint;

determining that an under pressure condition exists; and

in response to under pressure condition, increasing the supply of helium.

14. The method of claim 7 wherein the refrigerators are included in cryopumps.

15. The method of claim 14 wherein each of the cryopumps has one or more stages and determining the operating parameters further includes determining a temperature of at least one of the arrays at the stages.

16. The method of claim 7 wherein the determined pressure differential is substantially the same for all compressors connected to the compressor bank.

17. The method of claim 7 wherein the determined pressure differential is substantially the same for the compressor bank and the refrigerators.

18. A system for controlling distribution of a refrigerant among a plurality of refrigerators comprising:

a compressor bank including at least one compressor, the compressor including a high pressure supply line and a low pressure exhaust line, the compressor bank capable of supplying a refrigerant;

the refrigerant is helium;

a plurality of refrigerators coupled to the compressor bank, the refrigerators adapted to consume the refrigerant; and

an electronic controller capable of allocating the refrigerant to the refrigerators, the allocation of the refrigerant in response to operating parameters associated with the refrigerators, the operating parameters include a pressure differential based on a difference in pressure between the high pressure supply line and the low pressure exhaust line;

wherein the electronic controller reallocates the refrigerant in response to determining and redetermining the pressure differential.

19. The system of claim 18 wherein the determined and redetermined pressure differential is substantially the same for all compressors connected to the compressor bank.

20. The system of claim 18 wherein the determined and redetermined pressure differential is substantially the same for the compressor bank and the refrigerators.

21. The system of claim 18 wherein the allocating and reallocating of the refrigerant comprises varying the supply of refrigerant to the refrigerators depending on the operating parameters.

22. The system of claim 18 wherein the refrigerators are included in cryopumps.