Detonator

387,545. Blasting-detonators. BIAZZI, M. F. F., Brigue, Switzerland. April 13, 1932, No. 10634. Convention date, April 29, 1931. [Class 9 (i).] In manufacturing a blasting- detonator comprising a secondary charge 3 in a case 1 surmounted by a primary charge 4 in a capsule 2, the primary charge is compressed in its capsule before this is inserted in the case 1 over the secondary charge which has been previously compressed therein, and the capsule is then pressed down to insure intimate contact between the two charges. By this process, the primary charge has its zone of highest compression against the zone of highest compression of the secondary charge, a disposition most efficient for the transmission of the detonation. This separate compression of the primary charge also enables this charge to be more highly compressed than the usual process of compressing the primary charge direct into the case 1. The detonator may contain a primary charge of mercury fulminate in a copper capsule in an aluminium case containing a nitroaromatic compound ; or the case may be of copper and the capsule of aluminium filled with lead azide. Part of the secondary charge may be inserted in the capsule ; or an intermediate charge of nitropentaerythrite, trimethylenetrinitramine or the like may be used. The hole 6 in the base of the capsule may contain some of the primary charge or a small charge of flash transmitting composition to facilitate ignition. Specification 239,773, [Class 9 (i), Ammunition &c.], is referred to.