title: A microprocessor-controlled gas mixing device.
abstract: This paper describes the use of solenoid valves for the production of binary gas mixtures. The system is controlled by a microprocessor and is capable of delivering accurate flows and concentrations of gases over the ranges commonly used in anaesthesia. Since the flow produced by the valves is pulsatile, a system for mixing the gases and smoothing the pulses is described. A back pressure regulator is fitted downstream of each of two mixing/damping chambers and a method of using this as a flow transducer is described. The advantages of this system over conventional rotameters are discussed.
mesh_terms: D000769:Anesthesia, Inhalation / Q000295:instrumentation*; D003201:Computers; D004867:Equipment Design; D008838:Microcomputers; D009609:Nitrous Oxide / Q000008:administration & dosage*; D010100:Oxygen / Q000008:administration & dosage*
chemical_list: D009609:Nitrous Oxide; D010100:Oxygen