GB549602A - Improvements in refrigerating system - Google Patents

Abstract

549,602. Automatic control systems. UNITED FRUIT CO. Sept. 20, 1940, No. 14407. Convention date, Sept. 22, 1939. [Class 38 (iv)] [Also in Group XIII] The rate of circulation and the temperature of cooled air circulating through cold-storage chambers for bananas and other fruits &c. on board ship or elsewhere are varied in accordance with the temperature of the air leaving the storage space in such a manner as to maintain a rapid circuiation until a fresh cargo is cooled down to storage temperature and thereafter a reduced circulation, with automatic regulation of the flow of brine or other medium for cooling the air and of the refrigerating plant for cooling the brine. The several chambers W, X, Y, Z, arranged between decks are each equipped with two fans 20, 21 for circulating the air over brine coils 26, 28 through ducts 30, 32 along the sides of the chambers beneath floor slots 14 and back through discharge openings 18, as described in Specifications 393,345 and 424,133, [both in Group X]. The brine coils are connected through flow and return mains 80, 46 with vessels 90, 92 cooled by evaporators of a refrigerating machine having two compressors 100, 102 and condensers 108, 110 which may be cooled by sea water circulated by pumps 50. The fan motors are controlled by a thermostat 150 in the path of discharged air, valves 140, 142 in the brine return main 46 are controlled by thermostats 144, 146 in the delivery air ducts, and the compressor motors are controlled by a thermostat 160 in the brine supply main 80. In starting up of the plant the sea water pumps are put in action and the flow of sea water actuates a switch at 317 to close the compressor motor circuits. The brine supply thermostat 160 may be of the kind comprising a mercury column 500, Fig. 4 with high temperature contacts h, f, g and low temperature contacts a ... e connected with a fourpole switch manually set to the full line position shown and held there by a solenoid 519, automatic release being effected when the temperature falls below the lowest contact e. The brine valves are actuated by reversible motors controlled by the thermostats 144, 146, and the speed of the fans is regulated by adjustment of resistances in the fan motor circuits by the thermostat 500. After the plant has been started up and as the brine temperature falls, firstly the speed of one compressor is reduced, and then one sea water pump motor is stopped and the compressor thereby stopped. If the brine cools still further the other compressor is similarly controlled. The Specification as open to inspection under Sect. 91 comprises also a direct-expansion air cooling plant, the expansion valves and compressor motors being controlled in accordance with the air temperature. This subject-matter does not appear in the Specification as accepted.