Improvements in or relating to means for affording protection within living spaces against poisonous gases in the external atmosphere

摘要

464,248. Bellows. RUSSELL, F. J. Aug. 13, 1936, No. 22361. [Class 8 (i)] [Also in Group X] A manually operated positive action pump is employed in an enclosure to draw air from a layer of the external atmosphere above the layer vitiated by poison gas, and to use this air to create a pressure in the enclosure above that of the outer air, the ingress of which is prevented. An air inlet pipe 15, which extends outside the building or enclosure, and upwardly into a layer of pure air, has valved outlets 11, 13 entering through the ends 4, 5 of a double-acting bellows 1, 2. A partition 3 is reciprocated between the ends of a handle 7 and side members 8, which are fixed to the partition 3. Valved outlets 12, 14 are provided, all valves being of the non-return variety. In Fig. 5, the valves are arranged in the fixed partition 3, and the bellows enclosed in a rigid tubular housing 25 which is moved to- and-fro on rollers 27 by a handle 28. In a modification, the bellows is dispensed with, and a reciprocating piston in a cylinder is used.