GB383650A - Improvement in delay action blasting detonators and the like - Google Patents

Abstract

383,650. Blasting fuzes ; explosives. JACKSON, L. MELLERSH-, 28, Southampton Buildings, London.-(Hercules Powder Co. ; 900, Market Street, Wilming- ton, Delaware, U.S.A.) June 24, 1931, No. 18276. [Classes 9 (i) and 9 (ii).] The igniting charge or the timing train of a delay-action fuze or detonator is composed of an oxidizing agent such as barium peroxide, potassium chlorate, and potassium permanganate and an element of the right-hand column of group VI of the Periodic System such as sulphur, selenium, and tellurium, the said element being chosen with reference to the said oxidfzing agent so that the composition on combustion will produce no substantial quantity of gas and the casing of the fuze or detonator may therefore be ventless. An inert material such as barium oxide and magnesium oxide may be added to control the rate of burning of the composition. The rate of burning depends on the ingredients, their grain size, and the loading pressure. A suitable composition is a mixture of 85 per cent barium peroxide and 15 per cent selenium, each passing a mesh of 150 and loaded under a pressure of 5000 lbs. per square inch ; this gives a burning rate of 60 seconds per foot. The delay-action detonator, Fig. 1, comprises a detonator B containing a charge of mercury fulminate or a charge of tetryl primed with mercury fulminate, a delay fuze C containing a composition d of the kind stated above in a copper tube e wrapped in cloth f, and an electrically fired igniting charge H also of the kind stated above in a recess in a sulphur plug G covered with a waterproofing material I such as paraffin and sealed by a sulphur plug J. The ignition wire n may be coated with a mixture of diazodinitrophenol and potassium chlorate with a small quantity of a binder such as nitrocellulose. In a modification, Fig. 2, suitable where a certain amount of gas is generated, the plug G is a loose fit or is provided with a passage q to lead the gases to an absorbent o such as silica gel or activated charcoal covered by a plug L situated beneath the waterproofing material I.