GB458502A - Improvements in compressed air and like blasting cartridges - Google Patents

Abstract

458,502. Blasting cartridges. SAFETY MINING CO., 307, North Michigan Avenue, Chicago, U.S.A. March 16, 1935, No. 8268. Convention date, April 5, 1934. [Class 9 (i)] Relates to compressed-air and like blasting-cartridges of the kind in which a fluid-pressure-operated valve closes the cartridge when the pressure fluid is charged into the cartridge, and opens when the pressure is reduced, as described in Specification 429,807. According to the invention, the movable member of the valve consists of a single part wholly contained in the discharge end of the cartridge and has a surface adapted to seal the discharge port or ports and another surface exposed to the pressure of the charge. As shown in Fig. 1, the movable valve member is a sleeve 5 adapted to be pressed against an annular seat 8 to close the outlets 25 when pressure fluid is admitted to the cartridge through a central pipe 13, and passages 14, 15, 16, 17, 18, 21. Packing 6, 7 is provided to seal the rear and front ends of the valve member 5. A non-return ball valve 20 is inserted between the passages 18 and 21. The construction of the movable valve member may be varied according to the areas it is desired to expose to fluid pressure, and the valve may be arranged in a separate cup or junction member screwed to the cartridge, for example, as shown in Fig. 12. In the form shown in Fig 6, a number of cartridges are screwed end-to.-end and have their discharge outlets towards the rear ; and the non-return valve is a flat ring 57 controlled by a spring 33 on the central pipe 50. In modifications of this arrangement, the successive cartridges attached one to another have their discharge outlets all towards the front, or the discharge outlets of two adjacent cartridges are next to each other. In the form shown in Fig. 12, a cap 112 is secured to the front end of the cartridge and is provided with a screw-down valve 126 and a ball check valve 123 to enable the cartridge to be loaded with pressure fluid through a lateral port 127 before the cartridge is placed in the bore-hole. The discharge is performed by supplying compressed fluid through a pipe 133 to operate a spring-controlled piston 116 provided with a stem 119 which dislodges the ball 123 and relieves the internal pressure of the cartridge through vents 129, whereupon the outlet valve 5 is operated. In a modification, instead of the ball valve 123 and piston 116, a sealing disc adapted to be broken by a small electric detonator is used. The Specification as open to inspection under Sect. 91 describes also cartridges comprising an air chamber within the bore-hole and an additional chamber outside the bore-hole to provide a large charge of fluid pressure. An outlet valve at the inner end is operated by an axial rod connected to a piston in the outer chamber, which on both sides of the piston is connected to a different valve device to charge the cartridge and to cause its discharge. This subject-matter does not appear in the Specification as accepted.