METHOD AND APPARATUS FOR COOLING A LOAD

• US 3,721,101 A
• Filed: 01/28/1971
• Issued: 03/20/1973
• Est. Priority Date: 01/28/1971
• Status: Expired due to Term

• Current Assignee: Helix Technology Corporation (Azenta, Inc.)
• Original Assignee: John C. Sheppard, Thomas P. Hosmer
• Inventors: Hosmer, Thomas P., Sheppard, John C.
• Primary Examiner(s): Wye, William J.
• Application Number:
  US05/110,678
• Time in Patent Office: 782 Days
• Field of Search: 62/383,56,132,55.5,441,100 165/32,96
• US Class Current: 62/56
• CPC Class Codes: F02G 1/0445 Engine plants with combined cycles, e.g. Vuilleumier
• CPC Class Codes: F02G 2250/18 Vuilleumier cycles
• CPC Class Codes: F25B 9/14 characterised by the cycle used, e.g. Stirling cycle
• CPC Class Codes: F25D 19/006 Thermal coupling structure or interface
• CPC Class Codes: F25D 3/10 using liquefied gases, e.g. liquid air for cooling semiconductor devices H01L23/445

Abstract

Method and apparatus for cooling a load such as a sample for spectroscopic analysis, an electronic component or a cryopumping surface. A constant source of cryogenic refrigeration is controllably thermally engaged with the load by externally actuated means. That part of the refrigeration system requiring insulation is contained within an evacuatable chamber while the working zone containing the load is normally contained within another separate evacuatable chamber. These chambers may be in controllable fluid communication.

Claims

1. An apparatus for providing a working zone in which a refrigeration load can be maintained at a predetermined controllable low temperature in vacuum-insulated surroundings, comprising in combination a. primary fluid-tight housing means incorporating within it a first evacuatable chamber in which said working zone is located;

b. cryogenic refrigeration means extending into said primary housing means and being adapted to deliver refrigeration from a first heat station means;

c. auxiliary housing means, within said primary housing means, defining around the portion of said refrigeration means which extends into said housing means a second evacuatable chamber;

d. second heat station means within said working zone;

e. pumping means adapted to evacuate said first evacuatable chamber;

f. heat flow path means in fixed thermal contact with said first heat station means of said refrigeration means and adapted to make controllable thermal engagement with said second heat station means thereby to control the temperature of said second heat station means and of a load in thermal contact therewith; and

g. actuating means adapted to effect the controlled thermal engagement of said heat flow path means with said second heat station means.

2. a movable plunger within said fluid tight cylinder member and defining with the inner wall of said cylindrical member a narrow annular spacing;

3. An apparatus in accordance with claim 2 wherein said window system means comprises a plurality of window systems and said working zone is adapted to contain a sample in optical alignment with said window systems for spectrographic analysis.

4. thermal connection means between said first heat station of said refrigerator means and one of said relative thick cylindrical sections of said cylindrical member;

and wherein said actuating means comprises

5. An apparatus in accordance with claim 1 wherein said cryogenic refrigeration means comprises means to provide a liquefied cryogen.

6. An apparatus in accordance with claim 5 including radiation shielding means substantially surrounding said means to provide said liquefied cryogen.

7. An apparatus in accordance with claim 1 wherein a portion of said primary fluid-tight housing means also comprises at least a portion of said auxiliary housing means.

8. An apparatus in accordance with claim 1 including valve-controlled fluid communication means between said first and second evacuatable chambers.

9. An apparatus in accordance with claim 8 wherein said valve-controlled fluid communication means are located external of said primary fluid-tight housing means.

10. An apparatus in accordance with claim 8 wherein said first and second evacuatable chambers are isolated by a wall and said valved-controlled fluid communication means comprise an opening in said wall and a valve plug operable within said opening.

11. An apparatus in accordance with claim 1 wherein said second heat station means comprises a screw member adapted for engagement with said refrigeration load.

12. An apparatus in accordance with claim 1 wherein said second heat station means comprises a flat surface.

13. An apparatus in accordance with claim 1 wherein said second heat station means comprises tubing adapted for the circulation of a liquid cryogen therethrough.

14. An apparatus in accordance with claim 1 wherein said pumping means adapted to evacuate said first evacuatable chamber comprises mechanical and cryopumping means.

15. An apparatus in accordance with claim 1 including pumping means adapted to evacuate said second evacuatable chamber.

16. An apparatus in accordance with claim 15 wherein said pUmping means adapted to evacuate said second evacuatable chamber serves also as said pumping means adapted to evacuate said first evacuatable chamber.

17. An apparatus in accordance with claim 16 wherein said pumping means adapted to evacuate said second evacuatable chamber comprises mechanical and cryopumping means.

18. An apparatus in accordance with claim 1 wherein said flow path means comprises a flexible copper strip adapted for engagement with and disengagement from said second heat station and said actuating means comprises means to effect such engagement and disengagement.

19. An apparatus in accordance with claim 1 wherein said flow path means comprises a copper strip attached to said first heat station means, a spring support in thermal contact with said copper strip, a helical spring affixed to said spring support, and a copper disk to which said second heat station means is affixed;

and said actuating means comprises means to move said spring support whereby a controlled number of the coils of said spring may be brought into contact with said disk.

20. An apparatus in accordance with claim 1 wherein said flow path means comprises a closed tubing adapted for circulation of pressurized helium and pump means to circulate said helium therethrough at a variable rate;

and said actuating means comprises means to control the speed of said pump means.

21. An apparatus in accordance with claim 1 wherein said flow path means comprises

22. An apparatus in accordance with claim 1 wherein said second heat station means comprises a plurality of separate heat stations separately in controllable thermal engagement with said first heat station means.

23. An apparatus for providing a working zone in which a refrigeration load can be maintained at a predetermined controllable low temperature in vacuum-insulated surroundings, comprising in combination a. fluid-tight housing means;

b. wall means within said housing means defining therein first and second evacuatable chambers;

c. refrigeration-load heat station means located within said first evacuatable chamber;

d. cryogenic refrigeration means extending into said second evacuatable chamber and having a refrigerator heat station;

e. vacuum pumping means adapted to evacuate said first and second evacuatable chambers;

f. thermal switch means intersecting said wall means and in fixed thermal contact with said refrigerator heat station and adapted to make controllable thermal engagement with said refrigeration-load heat station means and a load in thermal contact therewith; and

g. actuating means adapted to effect the controlled thermal engagement of said thermal switch means with said refrigeration-load heat station means.

24. An apparatus in accordance with claim 23 wherein said wall means extends across the entIre cross section of said housing means and has associated with it means to extend the heat leak path around said thermal switch means where it intersects said wall means.

25. An apparatus in accordance with claim 24 wherein said wall means has an opening and a valve plug operable within said opening whereby fluid communication between said evacuatable chambers may be controlled.

26. An apparatus in accordance with claim 23 wherein said walls means is of the same cross sectional configuration as said housing means, is mounted concentric therewith to define a spacing between it and the internal wall of said housing means and is affixed to said housing on one end across said spacing and has an end member on the other end which is intersected by said thermal switch.

27. An apparatus in accordance with claim 23 including valve-controlled fluid conduit means connecting said first and second evacuatable chambers.

28. An apparatus in accordance with claim 27 wherein said vacuum pumping means comprise mechanical pumping means connected with said second evacuatable chamber and cryopumping means located within said second evacuatable chamber.

29. An apparatus in accordance with claim 23 including a refrigeration load in thermal contact with said refrigeration-load heat station means.

30. An apparatus in accordance with claim 29 wherein said refrigeration load is low thermal mass cryopanel means.

31. An apparatus in accordance with claim 29 wherein said refrigeration load is an electronic component.

32. An apparatus in accordance with claim 29 wherein said refrigeration load is a spectrographic sample.

33. An apparatus for cooling a load, comprising in combination a. cryogenic refrigeration means having a refrigerator heat station;

b. housing means defining an evacuatable chamber around at least that portion of said cryogenic refrigeration means which requires thermal insulation and providing a thermal barrier between said evacuatable chamber and its surroundings;

c. refrigeration-load heat station means external of said evacuatable chamber and adapted for thermal connection to a refrigeration load;

d. thermal switch means intersecting said thermal barrier, in fixed thermal contact with said refrigerator heat station and adapted to make controllable thermal engagement with said refrigeration-load heat station means and a load thermally connected thereto; and

e. actuating means adapted to effect the controlled thermal engagement of said thermal switch means with said refrigeration-load heat station means.

34. An apparatus in accordance with claim 33 including auxiliary housing means adapted to define an auxiliary evacuatable chamber around said refrigeration-load heat station means and its associated load, said thermal barrier comprising a portion of said auxiliary housing means.

35. An apparatus in accordance with claim 34 including valve-controlled conduit means providing fluid communication between said evacuatable chamber in which said refrigeration means is located and said auxiliary evacuatable chamber.

36. A method for maintaining a refrigeration load at a controllable temperature, comprising the steps of a. providing an evacuated working zone around said load;

b. maintaining said load in contact with a refrigeratable heat station within said working zone;

c. providing a source of refrigeration in an evacuated auxiliary zone maintained separate and distinct from said working zone by a barrier; and

d. transferring a controlled amount of refrigeration from said source of refrigeration to said refrigeratable heat station along a heat flow path which is in fixed thermal engagement with said source of refrigeration and which intersects said barrier separating said evacuated working zone from said auxiliary zone.

37. A method in accordance with claim 36 wherein said providing of an evacuated working zone and of an evacuated auxiliary zone comprises in part the cryopumping of residual gases after mechaniCal vacuum pumping on a cryogenically cooled cryopumping surface.

38. A method in accordance with claim 36 wherein said providing a source of refrigeration comprises cooling a heat station by a cryogenic fluid circulating in a mechanical refrigerator.

39. A method in accordance with claim 36 wherein said providing a source of refrigeration comprises cooling a heat station by circulating a cryogen fluid in contact therewith.