GB572573A - Improvements in or relating to canned foods and beverages incorporating exothermic heating devices - Google Patents

Abstract

572,573. Heating by chemical action. CALDWELL, W. A., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. Oct. 25, 1940, No. 15679. [Class 64 (ii)] A vessel containing foodstuffs contains an inner compartment charged with an ignitable composition which can be ignited from outside and which reacts without evolution of inflammable gas. The charge may be a powdered metal, alloy, or silicide, and an oxidising agent, e.g., calcium silicide and red lead and/or iron oxide, aluminium and iron oxide, ferrosilicon and red lead, or antimony and potassium permanganate, or the mixtures described in Specifications 383,650, 389,309, 430,750, 462,000 and 514,741, [all in Group XXI]. The intensity of the reaction may be controlled by varying the proportions or by adding talc or china clay. The ignition means may be touch paper coated with a nitrocellulose composition and dusted with a slag forming igniting mixture, or a length of quick match fuse, or percussion or friction ignition means may be used. An intermediate priming charge may be employed. The compartment may be lined with asbestos paper or a mixture of china clay and sodium silicate. The inner compartment 5, 6 of tinplate is soldered at 11 to the cover 1 of the foodstuff container, and is provided with an insulating lining 7. The charge 8 is retained by a plug 9 of glass wool or asbestos through which passes a fuse 12 with a priming composition 13 at its inner end. The outer end of the fuse passes through a vent 14 in the end plate which is closed prior to use by a soldered tear-off 15. In a modification the outer end of the fuse may terminate in a match head, and in another modification, Fig. 3, this is associated with a wire 19 coated with friction material which is pulled out to ignite the match head. In another modification, Fig. 4 not shown, the fuse is ignited by a percussion cap. The heating charge may consist of calcium silicide 50 per cent., iron oxide 50 per cent., or calcium silicide 32.5 per cent., red lead 60 per cent., talc 7.5 per cent. The priming mixture may be red lead 70 parts, calcium silicide 30 parts, china clay 8 parts. The fuse may consist of cotton impregnated with potassium nitrate and coated with a 50 per cent. solution of nitrocellulose in acetone. Specification 433,580 also is referred to.