Liquid Nitrogen for Refrigeration
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AREFRIGERATION system suitable for use in frozen-food delivery bodies and which makes use of liquid nitrogen has been developed in the U.S.A. by Air Products and Chemicals Inc., Allentown, Pa. Known as the Cryo-Guard system, only three basic parts are entailed, these being a tank of liquid nitrogen, a pneumatic thermostat control and a spray header. In operation, liquid nitrogen— which is stored at —196°C (-320'F)— is sprayed into the body at a rate needed to maintain any preselected low temperature, and the capacity is high enough to cause rapid re-cooling after the body doors have been opened.
The Cryo-Guard system is completely self-contained and requires no power source, thus it is less bulky than current powered refrigeration equipment, a further consideration being that space is not required for air flow. The nitrogen itself is odourless, inert and non-toxic. Although not, as yet, available to the British industry, the Cryo-Guard system is being applied to a fleet of vehicles operated by a frozen food distributor in Pittsburgh, and full details of the development are available from the British company—Air Products Ltd., 49 Poland Street, London, W.1.