GB382054A - Improvements in or relating to breathing appliances - Google Patents

Abstract

382,054. Respiratory appliances. DAVIS, R. H., 187, Westminster Bridge Road, London. Oct. 14, 1931, No. 28548. [Class 81 (ii).] In self-contained breathing apparatus, particularly for s u bmarine use, comprising a breathing bag 12 containing an absorbent canister 20 connected by a tube 11 with the mouthpiece, and carrying oxygen supply means such as an oxygen cylinder 14, strapped to the underside of the bag and communicating with a frangible oxygen capsule within the bag, a separate inflatable bag 21 is detachably connected with the bag 12, as by clips or turnbuckles 120, either at the top and bottom or at the top only, to increase the buoyancy of the apparatus or to compensate for loss of buoyancy on exhaustion of the breathing bag. The bag 21 may be inflated by the user through a cock-controlled tube 22 or by the provision of a frangible capsule of compressed air or oxygen in the bag, or by both means. A relief valve 25 may be provided on the side wall of the bag. In a modification the bag 21 is detachably secured to a part of the apparatus other than the bag 12, for example to harness on the back of the wearer, and is connected by a flexible tube with a two-way cock in the breathing tube 11, which permits the exhaled breath to be passed to the breathing bag or the bag 21 at will. Alternatively the bag may be provided with a detachable flexible tube which communicates with a non-return valve in the wall of the breathing bag and through which the auxiliary bag may be inflated. These features may be applied to any of the constructions described.