Patent GB-447399-A (GB)
Title: Improvements in or relating to intermittently acting absorption refrigerating apparatus
IPC: F25B17/00
Filed: 1934-10-09
Abstract: 447,399. Refrigerating. ELECTROLUX, Ltd., Luton, Bedfordshire.-(Assignees of Platen-Munters Refrigerating System Aktiebolag; 2, Norrmalmstorg, Stockholm) Oct. 9, 1934, No. 28872. Convention date, Oct. 9, 1933. [Class 29] Absorption systems.-In an intermittent system having a periodically heated generator and a thermally separate store of cooled solution, as described in Specification 431,266, a liquid seal interposed between the vapour space of the generator and the liquor storage system in broken at the end of the generating period as the result of variations of liquid levels in the apparatus, and residual generator vapour and vapour, evolved from condensate in the evaporator are led into the cooled liquor. The generator 10 heated by a central flue 19 communicates with a storage vessel 13 for liquor by a supply pipe 35, leading through a heat-exchanger 33 to a " pumping coil 20, and by a return pipe 31 leading to a pipe 34 opening above a gas seal into a stand pipe 1, which communicates with one end of an inclined absorber conduit 2. The vapour expulsion pipe 22 leads into an " equalizing " vessel 17, preferably heat insulated, which is connected by a pipe 25 to a rectifier 28 and by a drain pipe 48 to the outer coil of the heat exchanger 33. The expelled vapour passes from the rectifier into condenser conduits 11, having fins 27 in common with the absorber for cooling by air, and the condensate flows into the rectifier jacket and then rises through a pipe 30 to the dome of an evaporator 12. The absorber is connected by pipes 1, 3 to the storage vessel 13 and by pipes 4, 5 with an auxiliary " equalizing " vessel 6. An equalizing conduit 42 connects the upper part of conduit 25 with the lowest part of the vessel 13 and a conduit 43 with a U-seal 44 extends from the conduit 25 to the stand pipe 1. The evaporator is provided with a draining valve 53 and conduit for any solution accumulated in it during transport &c., and with an overflow device in a chamber 37 formed by a partition having an aperture 18. A pipe 36 is led from the chamber 37 to the seal 44 in pipe 43, and is heated at one point, preferably by welding it to the heat-exchanger. As the evaporator becomes filled solution overflows back to the liquor circuit through pipe 36. When pure liquefied refrigerant begins to overflow vapour is generated therefrom in the heated part of this pipe and passes into and circulates liquid in the conduit 43, including that in. the seal 44, to the stand pipe 1. The pipe 43 is now open to hot vapour from the generator, which passes therethrough into the stand pipe and influences a thermostat 60 on the pipe 43 to cut off the supply of heat. Vapour in the stand pipe 1 is quickly absorbed, the absorption period begins, and circulation of liquor from vessel 13 to the absorber is maintained by the flow of vapour from the evaporator through pipes 30, 25, 43 into the stand pipe 1. If all the vapour is not absorbed in the absorber 2, the surplus rises through pipe 4 into the auxiliary vessel 6 and displaces liquor therefrom into the vessels 13 and 17. This diminishes the effective liquid head and reduces the velocity of vapour entering the pipe 1 ; vapour, however, is now condensed or absorbed in vessel 6 and liquid is withdrawn from vessels 17, 13 to fill it, the effective head of liquid being thereby restored. When the flow of vapour ceases absorption takes place at the junction of conduits 43, 34, and liquid flows into pipe 43 to reform the seal 44. The thermostat 60 is cooled and a thermostat 61 on the evaporator becomes warmer, and the heat supply to the generator is restored. The overflow device of the evaporator comprises a wide bore tube 50 and a small bore U-tube 51. After solution and some refrigerant have overflowed at the end of the generating period and absorption has commenced, the liquid in the evaporator and in the tube 51 boils rapidly, and a'pocket of vapour collects at the top of tube 51 and prevents flow of liquid through this tube into the chamber 37.