A percolator vaporizer heated by reaction of neutralization of lime by carbon dioxide

To improve the humidification of anesthetic gases without use of electricity and its associated dangers the principle of the coffee percolator has been applied to a new vaporizer. Coffee percolators work by introducing steam-driven spurts of boiling water into a perforated coffee container. A water vaporizer, which functions on this principle, was used substituting the fresh gas inflow of an anesthesia machine as the driving gas. The vaporizer was placed in the center of the lime canister of a circle system with coaxial-valved respiratory limbs. The gas-water mixture percolated through a multiple wire mesh gauze filter that prevented the introduction of water droplets into respiratory channels. All gases emerging from the bottom of the canister and reaching the inspiratory valve passed through the vaporizer above water level. The circuit delivered gases containing 4 to 9 mg of H2O/L above saturated values at ambient temperature (20.5 mg of H2O/L) within 15 minutes, if the fresh gas inflow was set at 2.5 L/min.