Method for obtaining improved temperature regulation when using liquid helium cooling

• US 4,791,788 A
• Filed: 08/24/1987
• Issued: 12/20/1988
• Est. Priority Date: 08/24/1987
• Status: Expired due to Term

• Current Assignee: Quantum Design, Inc.
• Original Assignee: Quantum Design, Inc.
• Inventors: Sager, Ronald E., Simmonds, Michael B.
• Primary Examiner(s): Capossela, Ronald C.
• Application Number:
  US07/087,465
• Time in Patent Office: 484 Days
• Field of Search: 62/55, 62/514 R, 62/49
• US Class Current: 62/49.1
• CPC Class Codes: F17C 13/026 having the temperature as the parameter
• CPC Class Codes: F17C 2223/0161 cryogenic, e.g. LNG, GNL, PLNG
• CPC Class Codes: F17C 2227/0341 using another fluid
• CPC Class Codes: F17C 2250/0626 Pressure
• CPC Class Codes: F17C 6/00 Methods and apparatus for filling vessels not under pressure with liquefied or solidified gases

Abstract

A method for controlling the flow of a cooling medium such as helium into an insulated chamber surrounding a region to establish a stable thermal environment in the region over a wide range of cryogenic temperatures. A thermally insulated capsule surrounds a variable temperature capillary to precondition the helium before it flows into the insulated chamber. The capillary can be operated in different modes, depending upon the heating or lack of heating of the capillary. At low temperatures the capillary can pass the helium in its liquid phase, at high temperatures only a small amount of gaseous helium is passed, and at certain intermediate temperatures there is an ample flow of gaseous helium only.

Claims

1. In a system for drawing a cooling medium from a liquid phase supply of the cooling medium for passage through a thermally insulated chamber surrounding a region to establish a stable thermal environment in the region over a range of cryogenic temperatures, an improved method for controlling the flow of the medium through the chamber comprising the steps of:

defining a first capillary in communication with the liquid phase supply;

defining a second capillary having an inner diameter larger than the inner diameter of the first capillary and an inlet extremity in communication with the first capillary, and an outlet extremity in communicating with the insulated chamber;

thermally insulating the first capillary and the inlet extremity of the second capillary; and

applying heat to the first capillary to selectively adjust the temperature of the first capillary to a selected one of a plurality of temperature including a first temperature sufficient to vaporize the cooling medium as the cooling medium passes through the first capillary but not to significantly restrict the flow of the cooling medium therethrough and a second temperature sufficient to vaporize the cooling medium as the cooling medium passes through the first capillary and to significantly restrict the flow of the cooling medium therethrough.

2. The method of claim 1 including the step of immersing at least a portion of the outlet extremity of the large capillary in the liquid phase supply of the cooling medium.

3. The method of claim 1 including the step of immersing the small capillary, the large capillary, and a portion of the insulated chamber in the liquid phase supply of the cooling medium.

4. The method of claim 1 including the step of filing the region surrounded by the insulated chamber with cooling medium in its gaseous phase.

5. The method of claim 1 including the step of heating the insulated chamber to a temperature above the temperature of the liquid phase supply of the cooling medium.