Patent attributes
An air/oxygen blender, optionally with an associated oxygen analyzer, is provided with an exhaust valve in fluid communication with one or more of a proportioning valve and a gas outlet which periodically opens to vent gas therefrom. The exhaust valve is preferably an electrically actuated valve, most preferably a solenoid valve, controlled by a control unit which periodically opens the exhaust valve. In another embodiment, an oxygen analyzer is provided with an exhaust valve in fluid communication with an oxygen sensing chamber. Preferably, the control unit controls the frequency of exhaust valve opening and the time period of exhaust valve opening. A method of prevention of contamination of a lower pressure source air or source oxygen connected to an air/oxygen blender is accomplished by periodically venting of gas from the exhaust valve.
