GB328717A - Improvements in or relating to blasting cartridges - Google Patents

Abstract

328,717. Hodge, D. Feb. 20, 1929. Blasting cartridges and fuzes.-Relates to cartridges containing compressed carbon dioxide in a non-gaseous state closed in by a filling cap, and means for electrically heating the carbon dioxide to above its critical temperature. According to the invention, accidents are prevented by the provision of means for short circuiting the electric heater when the filling cap is removed. As shown, when the cap 12 is screwed on the cartridge case 1, a flange 45 inside the cap compresses a spring 43 away from a collar 11 on a central insulated electrode 2. When the cap is removed, the spring makes contact with the collar 11 and thus shorts the circuit of the heater 29, one terminal 39 of which is connected by a binding screw 41 and a socket 30 to the central electrode 2, while the other terminal 40 is connected by a binding screw 42 and a sleeve 33 to a bush 3 in electrical connection with the case 1. A flanged head 17 is attached to the central electrode 2 and contains a valve 18. A plate 22 is mounted on the head 17 against springs 27 and carries a socket 23 adapted to receive the plug 24 of a lead 25, which is insulated and detachably secured to the cap 12 by a sleeve 26. The cap is fitted with a socket 14 for a plug 15 on the other lead 16. When the lead 25 is not attached, the springs 27 press the plate 22 against the cap 12 and thus the heater is short circuited. When the lead 25 is secured to the cap, it compresses the springs 27 and holds the plate 22 away from the cap. The carbon dioxide can be loaded into the case 1 through a hole 54 in the head 17 when the cap 12 is removed and the valve 18 opened. The bottom of the case is closed by a rupturable disc 46 secured with a ring 47 by a screwed cap 48 provided with outlets 49 for the gases after the rupture of the disc 46. If the cap 48 and disc 46 are detached, the heater 29 may be unscrewed and its closing plug 51 detached for the replacement of the heating device therein. Specifications 313,333, 320,226, 328,716 and 329,636 are referred to.