Abstract: A non-reciprocating Stirling-cycle machine which overcomes problems associated with high drive mechanism forces and vibration that seriously hamper reciprocating Stirling-cycle machines. The design employs Wankel rotors instead of the reciprocating pistons used in prior Stirling machines for effecting the compression and expansion cycles. Key innovations are the use of thermodynamic symmetry to allow coupling of the rotating compression and expansion spaces through simple stationary regenerators, and the coordination of thermodynamic and inertial phasing to allow complete balancing with one simple passive counterweight, which is not possible in reciprocating machines. The design can be scaled over a wide range of temperatures and capacities for use as a cryogenic or utilitarian refrigerator or to function as an external heat powered engine.

Abstract: The subject invention relates to a Joule-Thomson cryostat or refrigeration system in which an expansion valve can be commandably actuated to partially withdraw the core of the expansion valve in order to dislodge and flush contaminants that have collected in the valve passageway, to open the expansion valve to increase flow to accelerate cooldown, and to control flow to regulate the amount of refrigeration produced.