Patent GB-282428-A (GB)
Title: Improvements relating to refrigerating apparatus
IPC: F25B15/12
Filed: 1927-12-16
Abstract: 282,428. Einstein, A., and Szilard, L. Dec. 16, 1926, [Convention date]. Refrigerating, absorption and special processes for. - In systems wherein a gaseous auxiliary medium is admitted to the evaporator and the mixture formed is separated by absorption of the auxiliary medium and condensation of the refrigerant, as described in Specification 250,983, butane or methyl bromide is used as refrigerant with ammonia as auxiliary medium and water as the absorbent for the ammonia. In the arrangement shown in Fig. 1, the evaporator 1 contains the liquefied methyl bromide, into which gaseous ammonia is led through a pipe 3 and rose 4 from a generator 17 containing a solution of the ammonia in water. The mixed gases pass from the evaporator through a pipe 5 to the combined absorber and condenser 6, to which weak solution flows from the generator through a pipe 7. The condensed methyl bromide collects below the strong ammonia, solution and flows back to the evaporator by a pipe 11. The strong solution passes through a pipe 14, which is heated tu lift the solution to a vessel 15 by the action of evolved gas bubbles, and from the vessel 15 the solution flows through a pipe 18 to the generator. The small quantity of ammonia separated in the vessel 15 passes by a pipe 16 to the absorbercondenser. The pressure of the ammonia gas should be relatively high, but less than 10 atmospheres; the excess pressure in the generator, equivalent to the difference between the heights h, h<2> of the liquid columns in the pipe 18 and in the evaporator, ensures effective flow of the ammonia in a gaseous state into the liquefied refrigerant. In order to avoid excessive flow of weak solution through the pipe 7, the end 19 of this pipe is throttled as by the provision of a porous cap which prevents flow of gas through the pipe when the liquid level has dropped below the end of the pipe. The pipes 7, 14 and 5, 11 may be formed into interchangers. In the arrangement shown in Fig. 2, the solution flowing from the absorber-condenser 20 through the pipe 21 is lifted to a high level P in the generator 23 by the action of evolved gas bubbles, and then flows down over longitudinal ribs on the pipe 21, where it meets the evolved ammonia gas and any steam carried thereby, thus effecting rectification and also partial cooling of the ammonia gas. In an arrangement employing butane as refrigerant, the strong ammonia solution flows from the absorber-condenser into the generator and the weak solution is lifted through a heated riser pipe to a vessel above, from which it returns through an interchanger and the cooling-jacket of the absorber-condenser into the latter. The pipe conveying the ammonia, from the generator may be provided with a rectifier. In a further modification, the gaseous mixture from the evaporator is caused to bubble through the solution in the absorber-condenser, and the liquid circulation is maintained by the difference in density of the strong and weak solutions. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the following :- Sulphur dioxide or carbon dioxide may be used as auxiliary media with water as solvent, or steam may be used as auxiliary media with sulphuric acid as solvent. A number of substances together may be used as auxiliary media with a number of refrigerants. This subject-matter does not appear in the Specification as accepted.