Seal for piston rod of stirling engine

Claim 1

A Stirling cycle hot gas engine having a sealing device about a movable piston rod in a region extending between a first working gas filled chamber at high cyclic gas pressure and a second crankcase chamber with oil therein to lubricate said piston rod and having gas therein at lower pressure, said sealing device comprising in combination, a resilient synthetic plastic ring about said piston rod in said region conically tapered away from said rod on both ends, a pair of complementary metal ring wedges tapered toward said rod and mating with the ring on opposite sides thereof to urge said ring toward said rod thereby to engage it at a position lubricated by said oil, spring means loading the rings in the axial direction of the rod, and a gas flow return conduit including a one way valve connecting said region to said high pressure chamber to provide a flow path for gases toward said high pressure chamber and tending to maintain in said region a gas pressure at the lower cyclic pressure.