| 摘要 |
974,542. Liquefaction of gases.. PETROCARBON DEVELOPMENTS Ltd. Dec. 4, 1962, No. 45789/62. Addition to 912,478. Heading F4P. The method of cooling a compressed gas stream to below 70‹ K. in a plurality of inclined heat exchangers in series traversed by a separate stream of the gas after expansion in a turbine as claimed in the parent Specification, is modified in that helium is used as the coolant gas. Hydrogen is liquefied by passing it at 10 atmospheres pressure through an ammoniacooled exchanger 53, a nitrogen-cooled exchanger 53, a nitrogen-cooled exchanger 54 where its. temperature is reduced to 70‹ K. and further cooling is effected in exchangers 55, 56, 57 in series and wet hydrogen at 22‹ K. is expanded at a valve 58 into a container 59; each of the exchangers 55, 56, 57 being cooled by a countercurrent flow of helium cooled by expansion at an associated turbine 55b, 56b, 57b at a pressure of 7 atmospheres. The helium circuits are fed in parallel from a common discharge line of a turbine 61 and exhaust into a second common line passing through an exchanger 60 serving to precool helium entering turbine 22. Also feed helium to turbines 56b, 57b is cooled in exchangers 56a, 57a traversed by helium leaving the warm ends of exchangers 56, 57. In a modification wherein helium is liquefied the expanded helium-cooled exchangers 43-47, Fig. 1 (not shown), are additionally cooled by return flow of unliquefied helium leaving the expansion valve 49.
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