GB1129781A - Cryogenic refrigerator - Google Patents

Abstract

1,129,781. Refrigerating. HUGHES AIRCRAFT CO. 17 March, 1966 [13 April, 1965], No. 11746/66. Heading F4H. The cold ends of the three cylinders of a Solvay engine contact thermally conducting discs 37 which abstract heat from coils 42, which, together with coils 41 around non-conducting discs 40, form a passage connecting a supply of compressed helium to a Joule-Thomson nozzle 15, cold gas from the nozzle cooling a parametric amplifier 46 through a conducting disc 107. Helium from the nozzle 15 passes in countercurrent flow over the heat exchange coils 41. The right hand disc 37 thermally communicates the cold end of the shortest cylinder with intermediate portions of the longer two, and the intermediate disc 37 thermally communicates the cold end of the intermediate length cylinder with a further intermediate portion of the longest cylinder so that the stream of helium passing to the nozzle 15 receives cold at progressively lower temperatures. The portions 42 of the helium passage contain carbon. The pistons of the Solvay engine are driven with 120 degrees phase differences by a swash plate assembly (24), Fig. 1a (not shown). Inlet and exhaust valves (31 and 32), Figs. 1a and 4 (not shown), for each cylinder are operated by cam tracks (28 and 29) on the swash plate assembly. The shortest and intermediate length cylinders have regenerators (as at 14 in Fig. 1b within their pistons through which gas is passed to and from the expansion spaces, and the longest cylinder has an external regenerator (19), Figs. 2 and 3 (not shown), which is in thermal contact with the three discs 37. In a modification, Fig. 6 (not shown), the three Solvay refrigeration stages are obtained by a stepped piston working in a stepped cylinder.