Helix Technology Corporation

Marshall J Smith

Philip A Lessard

In an expansion engine used in cryogenic refrigeration, a stepped inlet valve 10 and a stepped exhaust valve 11 are fluid activated to control high pressure gas such as helium into and out of the engine. Clearance seals in the stepped valve are achieved by sizing a small diameter of a stepped piston to a small bore and by sizing a sleeve 16 to a larger diameter of the stepped piston. The sleeve 16 fits loosely within a large bore, and is fixed into position by placing a wire of soft metal 9 between the sleeve and the wall of the cylinder.

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Danvers, MA, United States of America

Marshall J Smith