By=pass-type anaesthetic vaporiser - has vaporising chamber or return pipe connected to intermediate chamber with drain passage for anaesthetic into vaporising chamber

摘要

Either the vaporising chamber (5) and/or return pipes (19) are connected to an intermediate chamber (101) inside the vaporising chamber. This has a drain passage (102) returning any anaesthetic which has penetrated into it to the vaporising chamber. A section of this passage can run parallel to the surface of the liquid (13) in the vaporising chamber when the latter is full and upright, while the passage mouth can be above and clear (a) of the liquid surface. ADVANTAGE - No anaesthetic outside the vaporising chamber can affect the proportion of it in the mixture at the outlet if the vaporiser is wrongly positioned.