Refrigeration system and reciprocating compressor therefor with pressure stabilizing seal

A seal arrangement for the compressor of a refrigerator of the type comprising a reciprocating displacer within a cold finger, the displacer being driven in a reciprocating motion by the pressure differential between a gas in the cold finger and gas in a gas spring volume, the cold finger being in fluid communication with a space in a compressor cylinder, the compressor space and the cold finger defining a closed working volume of gas which is compressed and expanded by a piston in the compressor cylinder, said seal arrangement including an annular-lip seal of generally U-shaped cross section within a circumferential groove at the interface of the piston and cylinder and characterized in that said seal arrangement includes means for restricting axial movement of the seal to retain the annular lip of the seal spaced from the opposing faces of the groove, thereby maintaining a single direction of greater gas leakage past the seal and attaining a substantially constant mean pressure in the working volume.