GB818535A - Fuseheads - Google Patents

Abstract

818,535. Blasting fuzes and pyrotechnic compositions. IMPERIAL CHEMICAL INDUSTRIES Ltd. March 14, 1958 [March 20, 1957; Dec. 18, 1957], 9120/57 and 39311/57. Classes 9(1) and 9(2) An electric fuzehead in which electrodes extend into a bead 8 of a priming composition covered by a layer 11 of deflagrating composition and an outer protective skin 12, may have one or more layers of delay composition between the priming and the deflagrating compositions. A piece of pressboard 1 is sandwiched between the @rass foil electrodes 2 to which are soldered tinplated copper leads 6 and a bridge wire 3. The insulation 1 has a recess 5 to accommodate the wire 3 surrounded by the composition 8 which may be a mixture of red lead and finely ground silicon bound together by a solution comprising amyl acetate, amyl alcohol and nitocellulose. The wire 3 is coated by dipping it in the composition 8 and, after drying, one or more layers 9, 10 are formed by dipping in a slow-burning composition comprising red lead and coarse silicon in the same binder as the primer. After drying, the fuzehead is dipped in a deflagrating mixture comprising charcoal and potassium chlorate in an amyl acetate/nitrocellulose solution and dried before dipping once in collodion and four times in a solution comprising amyl acetate, amyl alcohol and nitrocellulose. High tension fuzeheads may be made in the same way, the bridge wire 3 and recess 5 being omitted and the primer being semiconducting. The slow-burning red lead and silicon composition may be replaced by a composition comprising zinc oxide, copper oxide and boron in the nitro cellulose binder. One layer of the slow-burning red lead and silicon composition may be used covered by two layers of a composition comprising zinc oxide and boron in a binder. The slow-burning composition may comprise bismuth powder mixed with finely ground selenium powder or antimony pentoxide mixed with manganese in a nitro-cellulose binder. Lead monoxide and silicon may form the bases of the slowburning composition. Finely ground silica may be incorporated in the red lead and coarse silicon composition. Lead dioxide may replace red lead in the priming composition