A valve for simultaneously controlling the flow of two propellant fluids to a rocket engine. The valve has separate flow passages for the two fluids and a separate valve element for controlling the flow through each passage. A single solenoid simultaneously controls the movement of both valve elements...http://www.google.es/patents/US4223698?utm_source=gb-gplus-sharePatente US4223698 - Solenoid operated bipropellant valve
