Patent GB-451253-A (GB)
Title: Improvements in intermittently acting absorption refrigerating apparatus
IPC: F25B17/00
Filed: 1935-01-29
Abstract: 451,253. Refrigerating. ELECTROLUX, Ltd., Luton, Bedfordshire.-(Assignees of Thomas, A. R.; c/o Servel, Inc., Evansville, Indiana, U.S.A.) Jan. 29, 1935, No. 2955. Convention date, Jan. 29, 1934. [Class 29] Absorption systems.-In an intermittent system of the type in which liquor circulates during the generating period between a small generator 10, 12 and an unheated storage vessel 25, liquor is withdrawn from circulation during the absorption period into a container 13, forming a dead end, by suction consequent upon cooling of the container. A liquid seal 41 between the vapour space of the generator and the storage vessel is broken when the liquid level falls in the generator due to generation, and is maintained open during the absorption period by accommodating the excess liquor from the storage vessel in the dead end container. The generator, comprising vessel 12 with narrow depending portion 10, is surrounded by a coil 22 in a flue 21 of a gas burner 19 or other heat source, and the vessel 13 is located in the upper portion of vessel 12 and connected to the lower liquid space of the portion 10 by concentric tubes 16, 17, the inner tube 16 being perforated at its lower end. Baffles 14 are located between the vessel 13 and the wall of vessel 12, which has external fins 15 for air cooling. The coil 22 is connected through the inner tube 23 of a liquor heat-exchanger 35 with the lower end of the storage and absorption vessel 25, and the portion 10 of the generator is connected by a tube 24, the outer tube 37 of the heat-exchanger and a rising pipe 38 with the top of the storage vessel. This vessel is divided by a partition 26 into upper and lower portions communicating through a passage between baffle tubes 29, 30 in such a manner as to permit movement of the liquid without turbulence. The vessel may be cooled by air or water or by a closed heat transfer system comprising an evaporator element 31 in the vessel and a condenser element 32, which may be cooled by the same fins as the condenser 44 of the refrigerating system itself. A conduit 40 connected with the generator vessel 12, at about the maximum liquid level A-A therein, and with the lower end of the storage absorption vessel 25, is formed with the U-seal 41 at about the minimum level C-C of liquid in the generator. Vapour from the generator is led through a rising pipe 43 to the condenser, from which liquefied refrigerant flows by gravity into the evaporator 45. The evaporator has an overflow device 46, 47 for draining absorption liquid, and preferably also a valved drain pipe for use in installing the apparatus after transport. The supply of fuel to the burner is controlled by a snap-action valve 52 actuated by a thermal element 49 in contact with the seal 41, which is in a cool condition while liquor circulates therethrough during the generating period and becomes warmed as soon as vapour flows therethrough at the end of the generating period. Another valve 59 in the fuel supply pipe is controlled by a thermal element 56 subject to evaporator temperature, this valve being closed so long as evaporation is taking place and opened when the evaporator warms up at the end of the absorption period. Initially liquid fills the generator to the level A-A, and on the application of heat the liquid is forced out of vessel 13 and circulates through the heat interchanger to and from the storage vessel. During this period conduit 40 and seal 41 remain filled with liquid and the storage absorption vessel is sealed against entry of vapour, As soon as the liquid level in the generator reaches the seal 41, vapour blows through it and is absorbed in reservoir 25. The thermal element 49 cuts off the supply of fuel, the temperature of the generator falls, and liquor is sucked up into the vessel 13. Evaporation ensues and the vapour flows through conduit 43, vessel 12 and conduit 40 to be absorbed in vessel 25. The rate of evaporation may be controlled by adjustment of a valve in the heat transfer system 31, 32 of the absorber. The effective liquor head for forcing vapour into the absorption vessel is the height H of the lower end of conduit 40 above the lowest level in the generator, and the latter level varies with the amount of cooling of the inner vessel 13. Further, if vapour is unabsorbed in vessel 25, it collects at the top and forces liquor downwards. The system thus adjusts itself during the absorption period. The fuel valve 52 opens again during this period and at the end of the period the other valve 59 opens and another heating period begins. In the modified apparatus shown in Fig. 2, the coil 22 alone is directly heated and is connected to pipe 11 in vessel 13 and to the bottom of an analyzer conduit 70, while the conduit 40 includes an equalizing vessel 74. Rectifier discs 76, 77 are fitted in upper part of conduit 70 in the finned conduit 43 leading to the condenser (not shown). The storageabsorption vessel comprises a lower baffled drum 25 and an upper drum 81 connected by finned pipes 75. The action of this apparatus is similar to that above described.