Helium management control system

Patent metadata

Field	Value
Publication number	US-10113781-B2
Application number	US-201214001803-A
Country	US
Kind code	B2
Filing date	Mar 5, 2012
Priority date	Mar 4, 2011
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A refrigerant management system controls the supply of refrigerant from two or more variable speed and fixed speed compressors to a plurality of cryogenic refrigerators. 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. The amount of refrigerant to supply is based on an aggregate demand for refrigerant from the plurality of cryogenic refrigerators and a refrigerant correction metric. An appropriate supply of refrigerant is distributed to each cryogenic refrigerator by adjusting the speed of the variable speed compressors or, alternatively, selectively turning the compressors on or off. The speed of the variable speed compressors is adjusted by determining an amount of refrigerant to supply to the plurality of cryogenic refrigerators. If the aggregate demand for refrigerant exceeds the capacity of the compressors, then the speed of a refrigerator within the plurality of refrigerators is adjusted.

First claim

What is claimed is:

1. A method for controlling supply of a refrigerant in a system, the method comprising, from a controller:
controlling a speed of a variable speed compressor and selectively turning on or off another compressor configured to deliver refrigerant to plural refrigerators based on a variable pressure differential between a supply pressure and a return pressure;
detecting a fault of a pressure sensor or a communication loss between elements of the system and, upon detecting the fault or the communication loss, increasing a controller determined speed of the variable speed compressor.

2. The method as claimed in claim 1 wherein the another compressor selectively turned on or off is a fixed speed compressor.

3. The method as claimed in claim 1 further comprising selectively turning on or off an additional compressor based on the variable pressure differential between the supply pressure and the return pressure.

4. The method as claimed in claim 1 further including:
increasing, based on the variable pressure differential, speed of the variable speed compressor; and
in response to increasing the speed of the variable speed compressor, turning off the another compressor.

5. The method as claimed in claim 4 wherein the speed of the variable speed compressor is increased as the another compressor is turned off.

6. The method as claimed in claim 4 further including delaying turning off the another compressor for a period of time.

7. The method as claimed in claim 1 further including shutting off a plurality of other compressors based on the variable pressure differential.

8. The method as claimed in claim 1 further including turning off the another compressor by selecting one of plural compressors to turn off based on a history of turn off.

9. The method as claimed in claim 1 further comprising controlling an additional variable speed compressors and, upon turning the additional variable speed compressor off, determining if the variable pressure differential between the supply pressure and the return pressure collapses by more than a predetermined threshold and, if the variable pressure differential collapses by more than the predetermined threshold, turning the additional variable speed compressor back on.

10. The method as claimed in claim 1 further comprising upon turning the another compressor off, determining if the variable pressure differential between the supply pressure and the return pressure collapses by more than a predetermined threshold and, if the variable pressure differential collapses by more than the predetermined threshold, switching compressor speed operational state.

11. The method as claimed in claim 1 wherein the another compressor is a fixed speed compressors.

12. The method as claimed in claim 1 wherein the another compressor is a variable speed compressors.

13. The method as claimed in claim 1 further including:
measuring the supply pressure and the return pressure; and
computing the variable pressure differential by calculating the difference between supply pressure and return pressure.

14. The method as claimed in claim 13 wherein the variable pressure differential is computed by
calculating an average differential between the supply pressure and the return pressure over a period of time.

15. The method as claimed in claim 1 wherein the refrigerant is helium.

16. The method as claimed in claim 1 wherein the refrigerant remains as a gas in all stages of refrigeration.

17. The method as claimed in claim 1 wherein the plural refrigerators are cryogenic refrigerators, which are included in cryopumps.

18. The method as claimed in claim 1 wherein controlling the supply of a refrigerant includes controlling supply of the refrigerant for cryogenic refrigerators.

19. The method as claimed in claim 1 wherein the another compressor is a variable speed compressor.

20. The method as claimed in claim 1 further comprising, upon detecting a loss or fault of the pressure sensor or a loss of communications to or from the pressure sensor, running the variable speed compressor at maximum speed.

21. The method as claimed in claim 1 further including, upon detecting a loss or fault of the pressure sensor or a loss of communications to or from the pressure sensor, increasing the speed of the variable speed compressor to a maximum speed.

22. The method as claimed in claim 1 further comprising:
in response to detecting the variable pressure differential between the pressure supply and the pressure return to be below a threshold value, determining if a refrigerator of the plural refrigerators is maintaining a specific temperature; and
if the refrigerator is maintaining the specific temperature, determining that the fault in the pressure sensor has occurred and setting the variable speed compressor to maximum speed.

23. A system for controlling supply of a refrigerant, the system comprising:
a variable speed compressor arranged to deliver refrigerant to plural refrigerators based on a variable pressure differential between a supply pressure and a return pressure; and
a controller arranged to control the speed of the variable speed compressor and selectively turn on or off another compressor based on the variable pressure differential between the supply pressure and the return pressure, the controller detecting a fault of a pressure sensor or a communication loss between elements of the system and, upon detecting the fault or the communication loss, increasing a controller determined speed of the variable speed compressor.

24. The system as claimed in claim 23 wherein the another compressor selectively turned on or off is a fixed speed compressor.

25. The system as claimed in claim 23 wherein the controller configured to selectively turn on or off an additional compressor based on the variable pressure differential between the supply pressure and the return pressure.

26. The system as claimed in claim 23 wherein the controller is configured to:
increase, based on the variable pressure differential, speed of the variable speed compressor; and
respond to the increasing speed of the variable speed compressor by turning off the another compressor.

27. The system as claimed in claim 26 wherein the speed of the variable speed compressor is increased as the another compressor is being turned off.

28. The system as claimed in claim 26 wherein the controller is configured to delay turning off the another compressor for a period of time.

29. The system as claimed in claim 23 wherein the controller is configured to turn off an additional compressor and to select one of the another compressors and the additional compressor to turn off based on a history of turn off.

30. The system as claimed in claim 23 wherein the controller is configured to determine, upon turning the another compressor off, if the variable pressure differential between the supply pressure and the return pressure collapses by more than a predetermined threshold and, if the variable pressure differential collapses by more than the predetermined threshold, the controller is configured to switch from a single variable speed compressor operational state to a dual variable speed compressor operational state.

31. The system as claimed in claim 23 further comprising the controller configured to dete

Assignees

• Dumas Oliver J
• Buonpane Maureen C
• Ball Difazio Doreen J
• Morris Ronald N
• Bartlett Allen J
• Loranger Leonard A
• Chopy Jr Joseph
• Sullivan Robert P
• Varone John J
• Amundsen Paul E
• Brooks Automation Inc

Inventors

• Dumas Oliver J
• Buonpane Maureen C
• Ball-Difazio Doreen J
• Morris Ronald N
• Bartlett Allen J
• Loranger Leonard A
• Chopy Jr Joseph
• Sullivan Robert P
• Varone John J
• Amundsen Paul E

Classifications

• F25J1/0294

  Multiple compressor casings/strings in parallel, e.g. split arrangement · CPC title

• F25J1/0269

  Arrangement of liquefaction units or equipments fulfilling the same process step, e.g. multiple "trains" concept (F25J1/0294 takes precedence) · CPC title

• F25J2270/912

  Liquefaction cycle of a low-boiling (feed) gas in a cryocooler, i.e. in a closed-loop refrigerator · CPC title

• F25B9/00

  Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point · CPC title

• F25J1/0245

  Different modes, i.e. 'runs', of operation; Process control · CPC title