Patent GB-734895-A (GB)
Title: Improvements in or relating to refrigerators
IPC: F25B9/00
Filed: 1953-06-05
Abstract: 734,895. Cold separation of gases. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. June 5, 1953 [June 10, 1952], No. 15560/53. Class 8 (2). [Also in Group XIII] The Specification describes several applications of a refrigerating machine operating on the reversed hot gas engine principle (see Group XIII) to the liquefaction of gases, e.g. air or to the separation of gaseous mixtures such as air or coke oven gases. As shown in Fig. 1, gas to be liquefied by the freezer 21 of the machine and collected by a trough 22 is precooled by a heat exchanger 18, 15 receiving cold from the regenerator 11, 12 of the machine. The gas enters at 19 and the precooling may serve to remove water vapour or carbon dioxide from the air to be liquefied. As shown in Fig. 6, gas to be fractionated in a column 70 is fed thereto by a pump 78 through a precooler 79 receiving cold from the regenerator of the machine and a second precooler 81. The evaporator 71 of the column 70 is heated by an auxiliary medium, e.g. nitrogen circulated by a pump 75 through a coil 74 in the evaporator and through a heat exchanger 76 in which the auxiliary medium gives up cold to the regenerator of the machine. Gas from the top of the column passes by pipe 83 to the freezer of the machine where it is liquefied, the liquid flowing in part by pipe 84 to the top of the column and in part by pipe 85 to the precooler 81. The fraction of higher boiling point is withdrawn through a cock 82, and that of lower boiling point from the precooler 81. As shown in Fig. 7, a mixture of three gases, e.g. oxygen, nitrogen and argon passes to the column 90 by way of pump 99, precooler 100, coil 102 which heats the evaporator 91 of the column, and pipe 103. Oxygen leaves the column by pipe 96 and coil 97 in the precooler and nitrogen leaving the top of the column passes in part through pipe 93 and coil 95 in the precooler and in part through pipe 107, heat exchanger 109 where it cools the regenerator of the machine, and pipe 110 to rejoin the other part in coil 95. Mixed nitrogen and argon leaves the column 90 by pipe 111 and is separated in column 112, the nitrogen collecting in the bottom and being pumped back to the main column through pipe 114. The argon leaves column 112 through top pipe 113. The condensers 92, 116 of the columns are fed in parallel with liquid nitrogen which is vaporized therein and recondensed by the freezer of the machine. A similar system for separating mixtures containing two gases and having no auxiliary column 112 is described with reference to Fig. 5. As shown in Fig. 8, gases are supplied to column 120 by pump 130, precooler 126 and pipe 131, one fraction passing from the evapor. ator 121 by pipe 135, heat exchanger 137, where it gives up cold to the regenerator of the machine, pipe 138 and a coil in precooler 126. The other fraction passes through top pipe 133 to be liquefied by the freezer of the machine the liquid flowing in part by pipe 134 to the top of the column and in part by pipe 135 for collection. Evaporator 121 is heated by compressed nitrogen from compressor 123, the nitrogen then flowing through a pressurereducing device 127 to the condenser 122 of the column to cool the column. From the condenser the nitrogen passes back to the compressor 123 through pipe 128. Specification 695,857, [Group XIII], is referred to.