GB760360A - New and improved delay fuse compositions and delay assemblies including same - Google Patents

Abstract

760,360. Delay fuze compositions. IMPERIAL CHEMICAL INDUSTRIES, Ltd. Jan. 3, 1955 [April 23, 1954], No. 11772/54. Classes 9 (1) and 9 (2). A delay fuze composition consists of or comprises titanium having a particle size not greater than 60Á, and preferably, a major proportion between 5Áand 35Á, e.g. all passing 300 B.S.S., and at least one oxidizing agent, e.g. lead dioxide, red lead, manganese dioxide, barium peroxide, or potassium permanganate, dichromate, or perchlorate. The ratio of titanium to oxidizing agent may be 60 : 40 to 10 : 90, and the mixture may be corned with an adhesive, e.g. 2¢ per cent. nitrocellulose solution in amyl acetate/amyl alcohol, to make the composition free flowing. The composition may include 10 per cent. inert diluent, e.g. sodium chloride, ferric oxide, magnesium oxide, and calcium fluoride, and other reducing agents, e.g. silicon, boron, aluminium, or magnesium. The composition is pressed into a brass sleeve and assembled as a delay element in a ventless copper electric delay detonator, containing a base charge of 0.55g. tetryl and a charge of 0.35g. of a mixture of lead azide, lead styphnate, and aluminium. The examples show proportions of ingredients for various burning times and quote delay times for assembled detonators. The compositions are subjected to a friction test and a heat test. In the former, a small amount of composition on a mild steel anvil is struck by a mild steel torpedo, having a hemispherical end, which slides down a plane inclined at 70 degrees. The distance of travel and weight of the torpedo are a measure of the sensitivity to friction. In the latter, a small amount of composition is heated in an empty copper tube in a bath of Wood's metal to determine the minimum temperature at which five consecutive samples ignite within 5 seconds.