Multiple cylinder refrigeration apparatus

A multiple-phase Stirling cycle refrigeration apparatus housed in an approximately cylindrical crankcase, which comprises:

• first, second, third and fourth piston cylinders arranged within the crankcase on a circle concentric therewith, said first and third piston cylinders, and said second and fourth piston cylinders, opposing each other across the center of the crankcase, said first and third piston cylinders being adapted to produce very low temperatures, said second and fourth piston cylinders being adapted to produce moderately low temperatures, each piston cylinder having a large diameter portion and an elongated small diameter portion;
• first, second, third and fourth pistons adapted for reciprocation within respective ones of said first through fourth piston cylinders, each piston having a large diameter portion and an elongated small diameter portion corresponding to the large and small diameter portions of the respective piston cylinder;
• the small diameter portion of each piston cylinder and of the respective piston within said piston cylinder delimiting an expansion space, the large diameter portion of each piston cylinder and of the respective piston within said piston cylinder delimiting a compression space on the expansion side of the large diameter portion of said piston;
• means interconnecting the expansion space of one piston cylinder with the compression space of the next adjacent piston cylinder for extracting refrigerating temperatures;
• and
• means for reciprocating said first through fourth pistons within said first through fourth piston cylinders in such a manner that said first and third pistons in said first and third piston cylinders, and said second and fourth pistons in said second and fourth piston cylinders, are displaced in phase by 180.degree..