Bimaterial demand flow cryostat

摘要

{PG,1 A demand-flow cryostat wherein a refrigerant is supplied through an elongated heat exchanger disposed in a container and the refrigerant is expanded through a Joule-Thompson expansion orifice at one end of the heat exchanger to provide an inventory of liquid in the container at that end and wherein a valve member for controlling a refrigerant flow through the orifice is located adjacent thereto and is movable relative to the orifice; whereby a throttling movement is effected with a reduction in temperature. The operation of the orifice and valve member characterized in that each is affixed to separate mounting means, each of which mounting means is associated with a separate control element composed of different materials whose mean cryogenic linear coefficients of expansion differ by at least about 1{33 10{hu {31 5 {l ({20 {0 K{HU {31 1{L ).