Patent ID: 7281383

Claim:
A refrigerator comprising, a sealed enclosure containing a cylinder and a piston, the piston driven in reciprocation within the cylinder by a crankshaft, one end of the crankshaft passing from the interior to the exterior of the sealed enclosure through a shaft seal, a work space bounded by the piston and cylinder, a high pressure heat exchanger designated herein by H, H having an inlet and an outlet, the inlet to H connected to the sealed enclosure by a sealed passage designated herein as PHIN, PHIN entering the sealed enclosure at a port designated herein as Hin, the outlet from H connected to the sealed enclosure by a sealed passage designated herein as PHOUT, PHOUT entering the sealed enclosure at a port designated herein as Hout, a low pressure heat exchanger designated herein by L, L having an inlet and an outlet, the inlet to L connected to the sealed enclosure by a sealed passage designated herein as PLIN, PLIN entering the sealed enclosure at a port designated herein as Lin, the outlet from L connected to the sealed enclosure by a sealed passage designated herein as PLOUT, PLOUT entering the sealed enclosure at a port designated herein as Lout, a one-way valve in a sealed passage between the work space and port Hin, a working gas filling the entire apparatus, a rotary valve rotating at one-half crankshaft speed, the rotary valve creating passages in the following sequence, a) in the interval between piston top dead center (TDC) and piston bottom dead center (BDC), the rotary valve creates a passage between the work space and L(out), b) in the subsequent interval BDC to TDC, no passage is created by the rotary valve, c) in the subsequent interval TDC to an angle of crankshaft rotation 2θ after TDC, where θ is an angle less than 90 degrees, the rotary valve creates a passage between the work space and H(out), d) in the subsequent interval from an angle of crankshaft rotation of 2θ after TDC to 2Φ after BDC, where Φ is an angle less than 90 degrees, no passage is created by the rotary valve, e) in the subsequent interval from an angle of crankshaft rotation of 2Φ after BDC to TDC, the rotary valve creates a passage between the work space and L(in).