Thermodynamic reciprocating machine comprising a compressor

Claim 1

In a thermodynamic apparatus including within a cylindrical bore of a housing, reciprocally movable coaxial compression and displacer pistons which define with the bore a variable volume working space, and a variable volume buffer space adjacent one end of the compression piston, said spaces comprising a closed system in which a gas is cyclically compressed and expanded, with the average gas pressure substantially equal in the working and buffer spaces, the improvement in combination therewith of a compressor for forcing gas from said buffer space out of said closed system, comprising a frame part of the housing within the buffer space defining a compression chamber including an sealable outlet, a compression element movable aXially within said chamber for varying the volume thereof, the chamber and element having adjacent relatively moving wall surfaces between which is a space operable as an inlet to said chamber, one of said adjacent surfaces having a groove therein, the groove having opposite top and bottom edges relative to said axis of the pistons, a sealing ring situated in said groove and having corresponding top and bottom edges, means for moving said compression element in phase with movement of said compression piston, the seal ring movable between first position with the top edges of the ring and groove in contact in sealing relationship, and second position with the corresponding bottom edges in contact and a gas passage defined therebetween whereby movement to said first position causes said ring to move until said bottom edges contact, and a volume of said chamber is reduced, and gas therein is compressed and forced through said outlet out of said system.