| 摘要 |
1,198.531. Respirators. GENERAL ELECTRIC CO. 13 Feb., 1968 [13 Feb., 1967], No. 7098/68. Heading A5T. [Also in Division B1] A respirator in which exhaled gases are recirculated] for inhalation after removal from them of CO 2 comprises a chamber 14 arranged for receiving exhaled gas and having a permeable non-porous wall 17 having a greater permeability to CO 2 than O 2 , a pump 23 for circulating air over the outside of the permeable wall to prevent build-up of CO 2 adjacent its outside surface and a conduit 28 for recirculating gases from the chamber 14 to the respirator gas supply conduits where it is augumented with oxygen from a container 31 or first cells operated in reverse, or air from a compressor (43 Figure 2). Desirably the gas supplied for inhalation contains about 50% oxygen by volume. The chamber 14 and a chamber through which air is circulated by the pump 23 are separated by the permeable wall 17 and provided in a rebreather unit 16. The wall is a thin film of dimethylsilicone rubber or a cellulose ester, e.g. cellulose acetate which may be impregnated with caesium bicarbonate and permit the removal of water vapour as well as CO 2 . The film is supported against rupture and albrasion by open-mesh cloths (19, 20 Fig. 3) on each side and a more rigid mesh screen (21). Nitrogen passes through the permeable wall into the respiratory system from the air circulated by the compressor 23. Undesirable, build-up of nitrogen within the system is prevented by the provision of a bleed. Gas flairing from tihe chamber 14 is returned to the gas supply conduit of the system through a breathing bag 29 and is mixed with supplementary oxygen from the container 31. Alternatively, the respiratory system may include two similar gas separators (44, 46, Fig. 2) each having an oxygen permeable membrane (48, 53). One (44) of the separators is supplied with atmospheric air from a compressor (43), and its output air, containing a higher proportion of oxygen than atmospheric air, is mixed with gases from the rebreather unit (42) and supplied by a second compressor (51) to the second gas separator (46) the output of which is connected through a demand regulator (57) to a mask (59). The rebreather unit may comprise several chambers in parallel each with a permeable wall area. |
