Patent GB-684600-A (GB)
Title: Improvements in or relating to hot gas reciprocating engines, and refrigerating engines operating on the reversed hot gas engine principle
IPC: F02G1/055
Filed: 1948-09-08
Abstract: 684,600. Refrigerating, Perkins and like tubes. NAAMLOOZE VENNOOTSCHAP PHILIPS GLOEILAMPENFABRIEKEN. Sept. 8,1948 [Sept. 11, 1947], No. 23642/48. Classes 29 and 64 (ii). [Also in Groups XXVI and XXVII] A hot gas engine or a refrigerating engine operating on the reversed hot gas engine cycle has a heat exchanger comprising a number of mutually independent tubes each passing through the wall of the engine head in a gas-tight manner and closed to the working medium and each containing a heat transfer medium and having a portion located externally of the engine head which portion can be heated or cooled the heat transfer medium in the portions of the tubes within the engine head thereby transmitting heat to or withdrawing heat from the working medium of the engine and the portions of the tubes within the engine head are arranged so as to surround one of the spaces for the working medium. Fig. 1 shows a hot gas engine in which the working medium has heat supplied to it by means of tubes 7 containing a heat conveying medium the tubes being heated at their lower ends by means of a burner 11. The heat conveying medium passes wholly or in part from liquid into vapour state and condenses in the upper ends of the tubes 7. Suitable materials for the heat conveying medium are metals, metal alloys, metal salts or a mixture of metal salts. Suitable metals are sodium, potassium, cadmium, caesium, zinc and lead or the metal salts zinc chloride, aluminium bromide, cadmium iodide, calcium iodide, zinc bromide or mixtures thereof may be used. Nitrates, nitrites or mixtures thereof are also suitable. In Fig. 3 the tubes 7 are replaced by tubes 24 which each form a closed circuit for a heat-conveying medium which remains in the liquid state in operation for example potassium or sodium or Woods metal or a low melting point potassium-sodium alloy. Under special conditions the tubes may be provided at an appropriate position with an aperture communicating with the surroundings. Fig. 5 shows an arrangement in which the tubes 7 are replaced by bent tubes 35 and a burner 39 is located within a wall formed by the ends of the tubes. In a modified form of Fig. 5 the ends of the tubes form a part conical jacket which surrounds the burner. Tubes containing the heat conveying medium may be divided internally by a partition which ends short of both ends of the tube so that a thermpsyphon effect is created in the medium. In one arrangement one end of the tube carries a partition while the other end is formed into two separate limbs which communicate with opposite sides of the partition the limbs being joined at their outer ends. Fig. 9 which is an end elevation shows another modification in which tubes 82 of closed straight form are used, and these are arranged to overlap one another. The source of heat is indicated at 83. It is stated that the construction of Figs. 1, 3 and 5 and the modification of Fig. 5 is suitable for refrigerators operating on the reversed hot gas engine principle. Either may in this case form the heat conveying medium. The Specification as open to inspection under Sect. 91, refers also to the use of zinc iodide as the heat conveying medium. This subject-matter does not appear in the Specification as accepted.