GB608536A - Improvements in or relating to apparatus for the administration of inhalant gas mixtures - Google Patents

Abstract

608,536. Gas-administration apparatus. BRITISH OXYGEN CO., Ltd., and JONES, W. Feb. 26, 1946, No. 5960. [Class 81(ii)] In apparatus for the administration of anaesthetic gas mixtures comprising expired gas and a proportion of fresh gas, there is provided means for incorporating in the mixture the vapour of a volatile liquid, said means comprising a flow-control mechanism operable in one position to permit mixing of fresh gas with expired gas followed by passage over the volatile liquid, and in another position to cause fresh gas to bubble through the liquid and the expired gas to pass over it, with subsequent mixing of the two gas streams. The apparatus shown comprises a carbon dioxide absorber A, valve means PA for controlling the flow of the expired gas therethrough and a vaporizer E for ether generally as disclosed in Specifications 550,296, 577,644 and 577,645. The said flow-control mechanism comprises a drum 10 connected through spindle 29 to operating knob 34, and serving in the position shown to pass the expired gas through port 12 and tube 19 over the ether, and thence via port 13, conduit 22, port 14 and the valve 15 to the face mark. Rotation of the drum progressively closes ports 12, 13, and brings a further opening (not shown) in the drum into register with port 14, thereby increasingly bye-passing the vaporizer. Also in the position shown, fresh gas passes through duct 16 and an opening (not shown) in the drum 10 to mix with the inspired gas stream. In the second position, the fresh gas passes via a tube 26 in drum 10 through a tube 18 to bubble through the ether, and thereafter mixes with the expired gas passing over it.. Inadvertent movement of knob 34 into the second position is prevented by the engagement of a stop 39 on a spring-urged pivoted lever 36 with a stop on the hoursing. The construction of the knob and safety mechanism is also shown in greater detail.