GB1388724A - Survival support devices - Google Patents

Abstract

1388724 Respirators LEAR SIEGLER Inc 9 May 1972 [10 May 1971] 21496/72 Heading A5T [Also in Divisions F2 and F4] A survival support device comprises a hood 11, Fig. 1, having a transparent front 14, an elongate hollow coil of high pressure tubing for containing a breathable gas at high pressure within the bore of the tubing, a regulator 29, Fig. 5, within the hollow of the coil for maintaining a substantially constant outlet pressure over a broad range of inlet pressures to maintain at substantially constant outlet flow, an actuator 26 within the hollow of the coil for substantially instantly providing fluid communication between the regulator and the tubing, and means for supporting the coil from the hood 11 at the rear thereof against the nape of the user's neck, the coil comprising coaxial inner and outer coils each in the form of a laterally flattened helix having a pair of straight parallel sides. The flow actuator 26 is coupled to the tubing via a tube 36 leading to a bore 38 in a body 35, the bore 38 communicating with a pressure gauge 42 and via a ball seal 44 with a bore 51 by means of which the coil may be filled on unseating ball 44 by unscrewing a plug 46. Removal of a pin 59 allows a spring 58 to force a plunger 56 to pierce an aluminium diaphragm 39 thereby permitting gas flow from the reservoir to the regulator 29. The Regulator 29 receives gas via bores 72, 73 and a chamber 74 having surface areas balanced so that the gas therein does not tend to move a piston 76. Gas escapes from chamber 74 between a blunt knife edge 77 and the piston 76 to pass into a chamber 79 wherein gas pressure urges the piston 76 against the action of a spring 78 towards edge 77. Gas passes from chamber 79 to the interior of hood 11 via a flow limiting orifice 83. The combination of parts 76, 77, 78, 79 and 83 is stated to provide a substantially constant flow rate of gas over a 20:1 range of gas pressure in the tubing reservoir, e.g. 5000 to 250 p.s.i.g.