GB1271019A - Safety closure for high pressure gas tanks - Google Patents

Abstract

1,271,019. Pipe couplings. HI-PRESSURE SYSTEMS Inc. 1 July, 1969 [1 July, 1968], No. 33235/69. Heading F2G. A safety closure and coupling 10 for the opening in a high-pressure gas container T, e.g. a scuba diving bottle, comprises a container sealing portion 12, which may screw into container T, enclosing flow passage 14 connecting a safety flow valve body 62, which fits into the container, with a shut-off valve 28 and an external connection 24. The flow valve member may comprise a ball 78 of non-corrosive material held away from valve seat 76 by spring 74, so that gas may flow through drillings 82, past ball 78 to passages 66, 14 and 16. A gas flow in excess of a limit predetermined by the strength of the spring and the geometry of the valve, e.g. caused by a rupture of closure 10, forces ball 78 against seat 76, thus restricting the gas flow to the small amount passing through by-pass 84. The by-pass 84 guards against pressure buildup when the tank is heated, e.g. in a fire, both by removing gas from the tank and by the cooling produced by expansion of the gas flowing through the by-pass. Extension 64 is preferably made of brass or other high thermal conductivity metal to aid heat transfer to the vented gas. In the embodiment shown rotating stop valve 28 in valve seat 20 by means of knob 48 connects passage 16 via counterbore 18 to passage 22 and thus to external connection 24. Passage 16 may contain a safety plug 58 of soft metal designed to blow out if the pressure in 16 exceeds 2500 p.s.i. at 100‹ F., and at a lower pressure at higher temperatures, to provide protection for the tank in case of fire. A back pressure valve (90, Fig. 2, not shown) having a closure (98) may be inserted into the flow passages (92, 22a) between the stop valve and the external connection, so that a spring (100) closes the valve when the pressure in passage (92) drops below 300 p.s.i. The user, e.g. a diver, having been thus warned by cessation of the gas flow that his gas supply has decreased to 300 p.s.i., turns a lever (126) to lift the valve closure member (98) off its seat (96), and makes use of the remaining gas. In another modification, the safety closure is so dimensioned that it may be enclosed within a cap (148, Fig. 3, not shown), screwed on to the gas container T, and the safety plug of soft metal is replaced by a rupture disc (13b) held over the open end of the passage (16b) by a masher (138).