GB576219A - Improvements in or relating to intermediate explosive primers - Google Patents

Abstract

576,219. Blasting detonators. TAYLOR, J., WRIGHT, H. R., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. July 29, 1942, No. 10586. [Classes 9 (i) and 9(ii)] An intermediate explosive primer adapted to transmit an enhanced impulse from a detonator or detonating fuze to a flame-insensitive cast explosive charge in the primer has a smaller charge of compressed explosive, more sensitive than the cast main charge, but also flame-insensitive, compressed within a tube which is interposed between the detonator and the larger charge of the primer in detonating contact with the main charge, the tube projecting at its closed end into a reduced part of the casing which receives the detonator. The larger and less sensitive charge for the primer may be cast from a molten mixture of T.N.T. and tetryl, or T.N.T. and pentaerythritol tetranitrate, or T.N.T. and cyclo-trimethylene-trinitramine, while the interposed relatively more sensitive charge may consist of compressed pentaerythritol tetranitrate, compressed cyclo - trimethylene - tri - nitramine or other compressed sensitive explosive. The primer shown comprises an open-ended casing 1 with an enlarged portion and an inner tubular member 2 closed at its inner end which is connected inside the casing at a shoulder by polyvinyl-acetate cement 3. The enlarged portion of the casing has cast therein the less-sensitive charge 10, a portion of which penetrates the inner tube to contact with the compressed more-sensitive charge 9 contained therein. The reduced portion of the casing is split at 4 and shouldered at 6 so that it can be easily clamped around a detonator or detonating fuze by a ring 8 when the detonator and primer are fitted together under field conditions. Specification 547,758 is referred to.