Patent GB-542685-A (GB)
Title: Improvements in or relating to absorption refrigerating systems
IPC: F25B47/02
Filed: 1940-09-30
Abstract: 542,685. Refrigerating. ELECTROLUX, Ltd. (Platen-Munters Refrigerating System Aktiebolag.). Sept. 30, 1940, No. 14748. [Class 29] Absorption systems.-In a continuous cycle inert gas system a liquid level is raised by displacement of an apparatus member to block the normal circulation of inert gas and thereby reduce the production of cold, as for defrosting the evaporator. The restoration of the circulation is preferably effected by thermostatic release of a latch holding the displaced member. In the system shown in Fig. 1 the displaceable member comprises a reservoir 30 connected by flexible conduits 31, 32 to the bottom of the outer jacket of the usual gas heat exchanger 20, where condensate accumulates in normal working, and by an overflow conduit 34 with the inner rich gas conduit 28 where it enters the absorber 22. In normal operation the level I in the reservoir is such as to leave a clear passage for weak gas from the conduit 35 to the exchanger jacket. The reservoir and conduits are raised manually by a lever. 45 to initiate a defrosting period, the liquid level being raised to the line II in the jacket and blocking the flow of weak gas from the absorber to the evaporator 16. The reservoir is fitted with a hook 42 adapted to be held by a spring catch 47, and a thermal element 50 near the evaporator transmits pressure to a bellows 55 to release the catch when defrosting is completed, and the reservoir is restored to its normal lowered position. The thermostat may be one employed for controlling the fuel valve 52 of the burner heating the generator 10. In the system shown in Fig. 2, having a partial jacket 72 outside the gas heat exchanger as described in Specification 537,507, a flexible and displaceable conduit comprising a U-tube 64 and spiral 62 is connected between the conduit 23 conveying weak solution from the generator 10 and the top of the coil absorber 22. A trap 66 is formed in the rich gas conduit 67 leading from the gas heat exchanger to the absorber and this trap is connected by a conduit 65 to the liquor conduit 23, while a drain conduit 73 connects the jacket 72 with the gas conduit 67. The normal liquid level is at the line I below the mouth 60 of the vapour expulsion pipe and below that of the normal drain conduit 65 of the trap. When the U-tube 64 is raised the level is lifted to the line II in the trap and in the generator, and the circulation of inert gas is stopped. At the same time the expulsion pressure is increased and a liquid seal in a vessel 77, normally blocking the flow of warm vapour from the generator to the evaporator is broken and the vapour passes directly to the evaporator to hasten the defrosting process. A construction of thermostatic release device is shown in Fig. 3 in which pressure transmitted from a capsule 50 to a diaphragm chamber 170 moves shaft 177 axially against the action of an adjustable spring 172 to release a drum 84 clutched to a disc 83 by a coiled spring 85 adapted to slip in one direction of movement of a casing 86 to which is secured a cord for raising the U-tube 64. Specification 522,576 is referred to.