GB1149767A - Gas supply systems - Google Patents

Abstract

1,149,767. Valves. BRITISH OXYGEN CO. Ltd. 15 Nov., 1966 [19 Nov., 1965], No. 49180/65. Heading F2V. [Also in Divisions A5 and G1] An assembly adapted to supply oxygen or oxygenated gas from a pressurized gas source 1, 25 for breathing, comprises a conduit 2, 5 in which there is a valve 4 biased so as to close the conduit, the valve being held open when the gas pressure is above a predetermined value, there being a signal device adapted to be operated by the gas, and there being means preventing the flow of gas to the signal device when the valve is held open. As shown, oxygen under pressure at a source 25 is mixed with nitrous oxide at a gas pressure source 1 and is supplied through the conduit 2, 5 to a face mask for anaesthetic purposes. The oxygen pressure is also available through a subsidiary conduit 12 at a piston 11 and normally the piston holds the valve 4 open against the action of springs 21, 26 and magnetic members 18, 19. The piston is provided with a resilient shoulder 13. Should the pressure of the oxygen fall, to avoid an excess of nitrous oxide in the breathing gas, the springs and magnetic members move the valve 4 to close the conduit and the oxygen is able to pass through a bore 16 in the lowered piston 11 and into a whistle 17. The assembly also includes a non-return valve 3, a relief valve 23, an inlet valve 22 through which ambient air may be inhaled, and an inlet 6 and relief valve 8 for use with an auxiliary oxygen supply in an emergency. The valves 22, 24 may also incorporate whistles to give warning of their operation. In an alternative embodiment (Fig. 2, not shown), the piston is combined with a diaphragm (30) and oxygen is available to the underside of the diaphragm and to the whistle (17) through restricted bores (12a, 12b) in the housing 10.