GB481166A - Improvements in or relating to charges for gas pressure operated blasting devices - Google Patents

Abstract

481,166. Blasting-charges. TAYLOR. J., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. Sept. 4, 1936, No. 24266. Addition to 453,210. [Classes 9 (i) and 9 (ii)] Relates to a charge for blasting-devices as claimed in the parent Specification, in which the gas-evolving composition contains a proportion of combustible carbonaceous ingredient. According to the invention, a substantial proportion of this ingredient is segregated from the remainder of the gas-evolving composition in coherent form and is arranged at least partly in the neighbourhood of the igniter. Thus it may be in the form of a waterproofed paper or cardboard tube with the igniter located therein. The-igniter may consist of a 30 to 100 grain powder fuze, an electric powder fuze as used for igniting black powder pellets, a safety electric igniter as described in Specification 431,950 or a small smokeless powder or cordite charge ignited in turn by a fuzehead or percussion cap. An extended tube of the carbonaceous material suitably sealed may be employed wholly or in part as a container for the active charge in the igniting element or, when an electric fuze is employed, one or both of the lead-wires may be passed through the tube from the igniter to their terminals in the device. The proportion of combustible carbonaceous ingredient distributed throughout the gas-evolving composition should not exceed 4 per cent by weight of the ammonium nitrate and preferably does not exceed 3 per cent whilst the segregated ingredient and the igniting element together should require at least about 45 grams of ammonium nitrate for their oxidation. Specification 430,258 also is referred to.