GB574017A - Improvements in or relating to the manufacture of delay fuze elements - Google Patents

Abstract

574,017. Blasting fuzes ; projectile fuzes. LOUDEN, J., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. Dec. 8, 1941, No. 15794. [Classes 9 (i) and 9 (ii)] A delay-fuze element for blasting, demolition and projectile uses, comprises a tube 1 of metal or other material, e.g. glass or porcelain, the inner end of which is either closed by an end wall which, by grooving or other mechanical means, is made weaker than the cylindrical wall, or has a pinhole 2 normally sealed by a thin coating 3 of film-forming material of a water-proofing character, such as nitrocellulose or a plastic or similar substance. The tube is filled under pressure with (a) a charge 4 of a heat-detonable explosive, and (b) a charge 5 of delay-burning composition. Such loaded tubes may be separated from the priming composition of the main detonator by an air gap. In an example, the explosive charge 4 may be 0.10 grams of a mixture containing lead azide 68 per cent, lead styphnate 29 per cent and aluminium powder 3 per cent. The delay composition 5 comprises 0.18 grams of monobasic lead 4 : 6-dinitroresorcinate. Both charges are loaded under a pressure of 10 tons per sq. in. This tube is suitable for a bomb detonator. In another example, in which pressures of 22 tons are used for both charges, the charge 4 is as above, but the charge 5 is loaded in two portions, the first being 0.28 grams of a 70 : 30 mixture of potassium permanganate and antimony and the second 0.04 grams of a 64 : 36 mixture of potassium permanganate and antimony. The first portion is loaded in seven increments.