GB430750A - An improved safety device for igniting explosives of the burning or non-detonating type - Google Patents

Abstract

430,750. Blasting-fuzes ; explosives. JONES, E., 6, Border Avenue, Saltcoats, Ayrshire, and IMPERIAL CHEMICAL INDUSTRIES, Ltd., Millbank, London. Dec. 20, 1933, No. 35804. [Classes 9 (i) and 9 (ii)] A safety igniter, specially for use with burning or non-detonating explosives, comprises an electric fuze-head 9 and a quantity of combustible material 2 both of the kind generating little or no gas sealed together in a metal container 1, the combustible material and the container being so correlated that the products of combustion do not escape from the container as a direct result of the complete combustion of combustible material, the temperature of a portion at least of the external surface of the container being raised to a temperature sufficient to ignite a blasting charge but insufficient to ignite mixtures of air with methane or coal-dust. The fuze-head may consist of a mixture of zirconium and lead mononitroresorcinate, as described in Specification 428,872. The combustible material may be a mixture of finely divided metallic substance and an oxidizing agent, for example red lead and ferrosilicon, calcium silicide and lead chromate, zinc and potassium permanganate, or iron and potassium permanganate. As shown, the fuze-head 9 is at the end of an insulating strip 3 attached by cement 8 to leads 5 passing through a lead or other deformable plug 6 in the mouth of the casing 1 or in an intermediate sleeve 4. An insulating washer 7 is used when the plug is of metal. Specifications 127,271, 127,272, and 276,962, [all in Class 9 (i)], are referred to. The Provisional Specification mentions the use of the igniter with the cartridges described in Specification 423,040.