GB821731A - A cartridge for use as a power unit - Google Patents

Abstract

821,731. Gas-generating cartridges; explosive compositions. OLIN MATHIESON CHEMICAL CORPORATION. March 28, 1957 [April 23, 1956], No. 10159/57. Classes 9(1) and 9(2) Gas-producing cartridge comprising rods 5 of a smokeless powder propellant embedded in a resinous matrix 15 has a case 1 with a thickened end 10 in which is a well 13 communicating with the primer recess 11. The case may be moulded from materials such as ethyl cellulose, polyethylene, polystyrene or cellulose acetate or made of metal e.g. brass, copper, steel. A spacer ring 8, which may be of the same material as the case or of natural or synthetic rubber, supports an annular ignition charge 7. This charge may be moulded from black powder or tetryl or may be black powder enclosed in a plastic bag of polyethylene or regenerated cellulose. The primer 12 may be electrically initiated or may be a conventional percussion cap. A composition is given comprising by weight 30-45 parts lead styphnate, 30-40 parts of an inorganic oxidant such as potassium nitrate, sodium nitrate, potassium bichromate, barium nitrate, lead peroxide and 15-30 parts of a fuel such as powdered aluminium or zirconium. The rods 5, which are perforated axially, may be made of nitrocellulose or mixtures of nitrocellulose with a liquid explosive polyhydric alcohol or from propellent compositions having a nitrocellulose base and containing an inorganic oxidant such as barium nitrate, potassium nitrate, potassium sulphate, ammonium nitrate, ammonium perchlorate, sodium perchlorate, potassium chlorate, lead peroxide, tin dioxide and lead stearate. Particles of metal, e.g. tin, aluminium, lead, may be included to modify the burning rate. Polyester resins, phenol formaldehyde or an epichlorhydrin-biphenol polymer may form the matrix. To inhibit the rods, the matrix Composition may be applied to the end faces adjacent the ignition charge 7. By varying the composition of the rods, a charge having any desired burning rate may be produced. In an example the rod composition is about 50 parts by weight gelatinized nitrocellulose, 45 parts nitro-glycerine, 3 parts diethylphthalate, 1 part ethyl centralite, 1 part potassium sulphate, 0.1 part candililla wax and 0.1 part powdered carbon black. To form the charge, the tubes of propellant are placed on metal rods 16, Fig. 3, and the rods 16 are inserted in perforations 17 of end plates 18, 19 of a mould. Side walls 20, 21 are secured around the rods and a spacer plate 23 is fastened between the end plates 18, 19. Molten resinous material is then forced into the mould through a port 24, the air displaced escaping through a port 27. The mould is then heated to cure the resin and after curing allowed to cool before the charge is removed. The charge may then be cut into the required lengths.