GB780742A - Subaqueuos breathing apparatus - Google Patents

Abstract

780,742. Respiratory appliances. SANCTIS, A. DE. June 25, 1954 [June 27, 1953], No. 18695/54. Class 81 (2). Subaqueous breathing apparatus comprises a chamber between a mouthpiece and a source of compressed air-oxygen mixture, water pressure responsive automatic valve means for controlling the flow of mixture from the source to the chamber, a valve connected to the mouthpiece for discharging part of the expired air, a breathing bag, for storing expired air, connected with the mouthpiece and with the chamber and at least one filter for retaining carbon dioxide flowing into the breathing bag. Oxygen and air is drawn, by air inspiration, along pipe 11 into a sheet-metal casing 4 and an inspiration pipe 2 to a mask 1. One side of the casing 4 is in the form of a diaphragm 14 which is exposed to the ambient pressure and operates a valve 13 in the gas supply. At the same time part of the air from a previous expiration is drawn through a carbon dioxide filter 6 into the casing 4 and the inspiration pipe 2. The remainder of the expired air escapes into the ambient atmosphere through a non-return valve 7. A chamber 5 is provided between an expiration pipe 3 and the filter 6. A breathing bag 8 is provided around the filter 6 and the casing 4. The valve 7, Fig. 5, consists of a rubber hose 32 having longitudinal slits 35 which are opened by escaping air against leaf-springs 30. Non-return valves may be provided in the inspiration and expiration pipes 2, 3. In alternative constructions (Figs. 3 and 4, not shown) the casing 4 is not surrounded by the breathing bag 8 and the valve 7 is situated in a chamber on the side of the diaphragm 14 which is exposed to the ambient pressure. An additional carbon dioxide filter may be provided between the casing 4 and the inspiration pipe 2 (Fig. 4, not shown).