John Patrick Gatewood

47794283, Oct 25, 1988

Oct 8, 1987

7/105847

Chung K. Chan - Los Angeles CA
John R. Gatewood - La Crescenta CA

United States of America as represented by the Administrator, National
Aeronautics and Space Administration - Washington DC

F25B 700

62467

A bi-directional Joule Thomson refrigerator is described, which is of simple construction at the cold end of the refrigerator. Compressed gas flowing in either direction through the Joule Thomson expander valve and becoming liquid, is captured in a container in direct continuous contact with the heat load. The Joule Thomson valve is responsive to the temperature of the working fluid near the valve, to vary the flow resistance through the valve so as to maintain a generally constant mass flow between the time that the refrigerator is first turned on and the fluid is warm, and the time when the refrigerator is near its coldest temperature and the fluid is cold. The valve is operated by differences in thermal coefficients of expansion of materials to squeeze and release a small tube which acts as the expander valve.