| 摘要 |
<p>1,056,964. Refrigerating. PHILIPS GLOEILAMPENFABRIEKEN N.V. March 2, 1965 [March 4, 1964], No. 8847/65. Heading F4H. A method of refrigerating comprises compressing a gaseous medium at 10 to above its critical pressure, cooling and liquifying it in heat exchanger 13, expanding the liquid medium to a pressure below its critical pressure at least in part in an expansion machine 14 without phase-transition occurring in the machine, using the expanded liquid to cool a load 18 and returning the vapour to the compressor via heat exchanger 13. The returning vapour cools the compressed medium to substantially the boiling-point of the expanded medium to ensure that phase transition does not occur in the machine 14. As shown, the medium from the machine 14 is further expanded in a throttle 16. For starting the system a valve 23 is used to direct the cooled medium to a throttle 21 until sufficient cooling is achieved in heat exchanger 13 to enable expansion machine 14 to be used. In a modification (Fig. 4, not shown), a coil (24) immersed in the liquid refrigerant is interposed between heat exchanger 13 and machine 14. In further modifications (Figs. 5 and 6, not shown), the expansion machine comprises a double-acting piston (60) reciprocating in a cylinder (59) to vary the volumes of upper and lower spaces (61 and 62). The compressed medium is supplied to space (61), displaced to space (62) via heat exchangers and one or more regenerators and expanded in space (62) by connecting cylinder (59) to the low pressure side of the compressor. The expanded medium returns to the compressor via said heat exchangers and regenerator(s) and is vaporized during its return in the heat exchanger nearest to space (62). The working medium may be hydrogen or helium.</p> |
