GB1314107A - Cryogenic cycle and apparatus - Google Patents

Abstract

1314107 Refrigerating CRYOGENIC TECHNOLOGY Inc 22 July 1970 35585/70 Heading F4H In a refrigeration system, a displacer or piston 11 moves within a housing 10 to define an upper fluid balancing chamber 14 and a lower expansion chamber 15 of variable volume. A first flow path 20 of high pressure fluid from a compressor 21 passes through a valve 25 into the expansion chamber, a second flow path 30 of low pressure fluid passes from the chamber 15 after expansion of the high pressure fluid through a valve 31, refrigeration load 32 and heat exchangers 24, 36 to the compressor 21 and a third flow path 37 extends between the balancing and expansion chambers 14, 15 via a regenerator 38. At least a portion of heat of expansion by compressing fluid within the chamber 14 is removed by heat exchange with the stream of low pressure fluid in the path 30 and the high pressure fluid is precooled prior to entry into the expansion chamber by heat exchange with the low pressure fluid in a heat exchanger 24. Means are provided to control the movement of the displacer 11 and operate the valves 25, 31 in correct sequence. The third path 37 may be located within the housing by placing the regenerator within the displacer, Fig. 5, or an extension of the housing may house a piston connected to the displacer communicating through valved ducts with both sides of the compressor, Fig. 6. The apparatus described with reference to Fig. 7 is constructed for open cycle operation wherein the displacer is pneumatically driven by providing separate sources of high and low pressure fluid so that the low pressure fluid is not recycled and high pressure fluid must be supplied continually. The heat exchanger 36 may be replaced by a coil around the or each balancing chamber when a plurality of housings are provided as in Figs. 9 to 11, each having means to move a displacer or piston therein, or a series of balancing and expansion chambers may be formed within a single housing, Fig. 12. Figs. 9 to 13 illustrate staged refrigerators suitable for attaining cryogenic temperatures or serve as liquefiers by connection to Joule- Thompson circuits, Fig. 12.