Patent ID: 8959929
Filing Date: 2015-02-24
Classification: F25B

Abstract:
1. A refrigeration device comprising: a crankcase; a compression cylinder disposed within the crankcase and ending in a cylinder head; a compression piston movably disposed within the compression cylinder, the compression piston separated from the cylinder head by a compression volume and dimensioned with a gas sealing fit with respect to the compression cylinder to prevent pressurized gas from escaping from the compression volume into the crankcase; a cold finger tube extending from the crankcase; an expansion cylinder disposed within the crankcase and extending to the cold finger tube, the expansion cylinder including a first fluid port in fluid communication with the compression volume through a fluid conduit extending from the cylinder head to the first fluid port; a gas displacing piston comprising a fluid control portion disposed in the expansion cylinder and a regenerator tube located in the cold finger tube, the fluid control portion including annular bearing surfaces configured to provide a gas seal between the fluid control portion and the expansion cylinder; a first regenerator matrix disposed entirely within the regenerator tube and characterized by a first diameter; and a second regenerator matrix disposed entirely within a thermally insulated cavity of the fluid control portion and characterized by a second diameter smaller than the first diameter; wherein the second regenerator matrix is physically separated from the first regenerator matrix by a thermal barrier and a first fluid passage extending between the first regenerator matrix and the second regenerator matrix; and wherein the fluid control portion includes a second fluid passage extending between the second regenerator matrix towards the first fluid port.