Figure 9-16 Simplified schematic drawing of the North American Dräger Vapor 19.1 vaporizer. Automatic temperature-compensating mechanisms in bypass chambers maintain a constant vaporizer output with varying temperatures. An expansion element directs a greater proportion of gas flow through the bypass chamber as temperature increases. (Modified from Andrews JJ, Brockwell RC: Delivery systems for inhaled anesthetics. In Barash PG, Cullen BF, Stoelting RK [eds]: Clinical Anesthesia, 4th ed. New York, Lippincott-Raven, 2000, pp 567–594.