Patent GB-445692-A (GB)
Title: Improvements in or relating to intermittently acting absorption refrigerating apparatus
IPC: F25B17/00
Filed: 1934-10-09
Abstract: 445,692. Refrigerating. ELECTROLUX, Ltd., Luton, Bedfordshire:-(Assignees of Platen-Munters Refrigerating System Aktiebolag; 2, Norrmalmstorg, Stockholm, Oct. 9, 1934. No. 28873. Convention date, Oct. 9, 1933. [Class 29] [See also Group XVIII] Absorption systems.-In an intermittent system in which liquor circulates during absorption periods between a storage vessel and a point of absorption, a gas lift pump effecting the circulation is started by evaporation of condensate overflowing from the evaporator at the end of each generating period, and is maintained in action by normal flow of vapour from the evaporator during the evaporating - absorbing period. The system, shown diagrammatically in Fig. 1, includes a generator 216 and a storage vessel 210 for liquor, preferably cooled, connected by a pipe 221, a heat-exchanger 220. a " pumping " coil 223, and a return pipe 224. Generated vapour passes by a pipe 300 to an analyser vessel 257 and thence by a pipe 240, gas chamber 235, liquid seal 236, and rectifier conduit 241 to a condenser 226, Liquefied refrigerant is forced from the condenser through a pipe 303 to the top of the evaporator 229, which is provided with an overflow device comprising an inverted U- pipe 305, a wide bore conduit 304 and a downflow conduit 233 connected to the conduit 304 at the upper liquid level in the evaporator. The U-pipe 305 is heated as by contact with the condensate pipe 303 or with the hot gas pipe 238. The conduit 233 is heated by contact with a part of the liquor heat exchanger at 350 and then connected with a conduit 213, which forms part of the circulation system between the storage vessel 210, the absorber 306, an equalizing vessel 310 and the analyser 257. The equalizing vessel is divided into two parts by a partition 309 and liquor overflows from the right-hand compartment over an inclined ribbed plate 312 to promote absorption in the left-hand compartment. Towards the end of the generating period the evaporator becomes filled and heavier solution first overflows through the pipes 305, 304 and 233. When pure liquefied refrigerant begins to pass into the U-pipe 305 it evaporates therein and forms a gas pocket to restrict flow from the bottom of the evaporator, and the liquid level rises until pure refrigerant flows into the top of pipe 304 and into pipe 233. As this liquid passes the heat - exchanger at 350 it is vaporized and the vapour on entering pipe 213 lifts and circulates the stored liquor from vessel 210 through the absorber 306 and the equalizing vessel 310. In the left-hand compartment of this last vessel the residual vapours of the generator system are absorbed and liquid columns rise in pipes 237, 238 to prevent return of refrigerant vapour through the analyser. The sinking of liquid in a connecting pipe 242 opens a path for vapour from the evaporator through the condenser and this pipe 242, whereby the liquor circulation through the pipe 213 is maintained during the whole evaporating-absorbing period. The heat of absorption developed in the pipe 213 as soon as refrigerant overflows from the evaporator may be used to influence a thermal element 320 to close a valve 333 in the fuel supply conduit 336 to the generator. A second valve 337 in the same conduit is controlled by a thermal element 342 associated with the evaporator, whereby the heat remains cut off so long as the evaporator or its surroundings is at a low temperature. In the practical embodiment shown in Fig. 2, the rectifier 241 is cooled by refrigerant from the condenser evaporating in a jacket, and the evaporator overflow pipe 233 passes inside the wide bore pipe 304, which extends through the evaporator. The condenser and absorber may be air cooled and have common fins 227. For preventing corrosion 1 to 2 per cent of potassium chromate may be added to water used as absorption medium, in the proportion of .1 to 2 per cent by weight.