The influence of pressure swings on the output of plenum vaporizers

The influence of pressure swings on the output of Dräger Vapor, Dräger Vapor 19, Cyprane Fluotec Mark 2, Cyprane Fluotec Mark 3 and Ohio halothane vaporizers was investigated. It is shown that significant deviations from the dial setting occur with all vaporizers if the swings are large enough. The sensitivity for pressure swings is largest at low dial settings and low carrier flow rates. The results indicate that swings, occurring during assisted or controlled intermittent positive pressure ventilation, can induce significant deviations at low carrier flow rates. The frequency and in-/expiration time ratio are relatively of minor importance.