Multi-stage refrigerating arrangement

939,365. Refrigerating. PHILIPS' GLOEILAMPENFABRIEKEN N.V. May 29, 1961 [June 1, 1960], No. 19296/61. Class 29. A reversed hot-gas engine type refrigerating machine is cooled and driven by the expansion of a gas acting on the remote side of its piston and supplied from a separate compressor unit. The engine comprises piston VI and displacer XI carried on coaxial shafts IX, X, respectively, coupled by linkwork XII to reciprocate with the appropriate phase difference. These shafts work in a tubular body IV which, together with the shafts includes valve passages and ports adapted to admit gas from compressor 51 through cooler XV and pipe II to the space V beneath piston VI and to allow expanded gas to return from this space through pipe III to compressor 51. The working space VII of the engine and the space V beneath piston VI include annular baffles 62, 65 which are received in annular recesses in the piston and around which the gases are obliged to flow. Fins are provided in the recesses and the piston is made of thermally conducting material so that the gas expanding in space V to drive the engine cools the gas being compressed in space VII of the engine. A regenerator 67 is provided between space V and the source of compressed gas.