摘要 |
An anaesthetic vaporizer of the by-pass type in which the concentration of anaesthetic vapor in the gas leaving the vaporizer is controlled by a valve arrangement which is capable of varying the resistance to gas flow of a second or by-pass stream which effectively alters the proportion in which the carrier gas is divided between said second by-pass stream and a first stream which passes through a vaporizing chamber. The valve arrangement includes a valve body 32 rotatable within a valve housing 30 having three spaced inlet holes 33, 35, 37 and an outlet hole 40 for the second gas stream. Rotary movement of the valve body 32 variously covers or uncovers the inlet holes 33, 35 and 37 to vary the resistance to the flow of the second stream from the inlet holes to the outlet hole 40 of the housing 30. |