Abstract: The cold cylinder assembly for a two stage Vuilleumier cycle cryogenic refrigerator having an outer cylinder forming a first chamber of a large diameter and a second chamber of a smaller diameter with a cold displacer within the cylinder. The cold displacer includes a first stage regenerator and a second stage regenerator. Gas from the crankcase passes through channels in the rider ring and then through ports to an annular passage within the cold displacer and then to the first stage regenerator. Gas from the first stage regenerator divides into two parts with one part passing to the second stage regenerator and then through passages to ports to impinge on an end member for the second stage heat load. The other part flows through passages to ports to impinge upon an end wall for the first stage heat load.

Abstract: The hot cylinder for a Vuilleumier cycle cryogenic refrigerator having an annular liner positioned between the hot displacer and the hot-cylinder wall with a plurality of stainless steel tubes in the space between the liner and the hot-cylinder wall to form a hot regenerator. The liner axially supports the tubes and has air flow notches at the top and bottom thereof. The gas flows through the tubes and through the spaces between the tubes. An annular seal is provided between the hot displacer and the annular liner.