Detachable cryogenic refrigerator expander

A refrigeration system, comprising

• a cold box including a first self-sealing coupling for conveying cryogenic gas, and
• a detachable work extraction system, including an expansion engine having a second self-sealing coupling for conveying cryogenic gas, the second self-sealing coupling detachably connecting the expansion engine to the cold box self-sealing coupling.

A method for connecting a cold box and a work extraction engine to convey cryogenic gas therebetween, comprising:

• detachably connecting the work extraction engine to the cold box, and
• removably disconnecting the work extraction engine from the cold box without substantial loss of gas from the cold box.

A detachable work extraction system, comprising:

• a single-phase gas expansion engine including a self-sealing coupling adapted to detachably connect the expansion engine to a cold box, and
• a hydraulic work extractor operatively connected to the expansion engine,
• wherein a gas can travel from the cold box to the expansion engine through the self-sealing coupling, the gas is cooled by expansion of the gas in the expansion engine and work produced by the expansion of the gas is dissipated by the hydraulic work extractor.