GB438980A - Improvements relating to respiratory appliances for protection against noxious gases - Google Patents

Abstract

438,980. Respiratory apparatus. SMITH, A. LEIGH-, 30, Smith Square, Westminster, and RICHARDSON, H. O. W., 24, Adelaide Road, Hampstead, London. July 17, 1934, Nos. 20884 and 21804. [Class 81 (ii)] In respiratory apparatus for protection against noxious gases comprising a pump, an air purifier and a reservoir leading to one or more masks, the pump preferably comprises a bellows 1 and forces air through a purifier 2, on which the bellows may be mounted, into the reservoir 4 which is of flexible material and devoid of internal operating devices. The reservoir 4 leads through a non-return valve 5 to a mask from which air is exhaled through a valve 6. The bellows 1 is preferably carried on a body belt 3. An additional pipe may lead from above the valve 5 to a separate mask for a child. In a modified construction a separate bellows leads to an elongated filter canister connected by a tube to a point between the valve 5 and a reservoir closed at the bottom, a valve cutting off the reservoir in case of damage being provided. For supplying a number of persons a bellows and an elongated canister with a screw cap are mounted on a separate stand, the canister being connected through branching pipes, through a large reservoir to individual masks, or to individual reservoirs and masks. The canisters may contain a cotton-wool filter, alkaline and drying filter material such as soda-lime and calcium chloride, and adsorptive charcoal, and a wet filter for humidifying the filtered air may be connected between the canister and the reservoir. One of the Provisional Specifications describes the purifying components as contained in tubes, the cotton wool being enclosed in a wide, and the charcoal in a long, closable tube. The other Provisional Specification refers to a filter canister in which the soda lime is carried in a separate removable container.