GB1198354A - Refrigeration System for Shipping Perishable Commodities - Google Patents

Abstract

1,198,354. Refrigerators. CRYO-THERM Inc. 28 Feb., 1968, No. 9590/68. Heading F4H. Perishable commodities are cooled during transport in portable containers, trucks, railway cars or ships by a fluid circulating heat transfer system which is arranged to surround the commodities and includes a heat-exchanger cooled to refrigeration temperatures by a cold source, at least the major portion of the heat transfer system being occupied by liquid. As shown in Fig. 1, the heat transfer system comprises interconnected heat exchange plates 13, 14, 15, 16, e.g. of the roll-bonded type, connected by a supply line 29 and a return line 32 to a heatexchanger 23. A coil 26 in the latter is supplied with liquid nitrogen from a vessel 11 under the control of a solenoid valve 35. The heat transfer system is partially filled with a liquid such as alcohol, acetone, carbon tetrachloride or a halogenated hydrocarbon, and in operation acts as a closed condensing-evaporating system. Valve 35 may be thermostatically controlled. The cold-source may alternatively comprise dry-ice (Fig. 6, not shown) or a mechanical refrigeration system. In the embodiment of Fig. 8, the heat transfer system 91 contains a non-evaporating liquid which is circulated by a pump 95 and cooled by direct contact with liquid nitrogen in a cyclone 90. The latter has an outlet tube 102 for nitrogen vapour. The warmed nitrogen vapour may be discharged to atmosphere or supplied to the interior of the container to provide a preservative atmosphere. In the latter case the nitrogen is supplied to a Venturi in which it induces and mixes with a stream of outside air before passing to the enclosure. The incoming air may be cooled by air and nitrogen leaving the enclosure (Figs. 10 and 12, not shown) and gas analysers may be provided for controlling the amounts of air and nitrogen, as well as carbon dioxide from a reservoir, admitted to the enclosure (Fig. 13, not shown).