Auxiliary Power Unit (APU) Feed Shutoff Valve (SOV)

The auxiliary power unit (APU) feed shutoff valve is a ball valve comprised of an aluminum alloy body assembly and ball, polytetrafluoroethylene ball seats, and a stainless steel drive shaft. It is installed with, and is operated by, a motor actuator that is powered at a nominal 28 VDC. Together, the APU feed shutoff valve and associated motor actuator provide a reliable, commanded capability to cut-off fuel flow to the APU within a few seconds. The APU feed shutoff valve is installed in the APU feed fuel line to prevent hazardous quantities of fuel from flowing into the APU compartment. The valve installation also provides a manual override in case of an actuator failure, and a position indicating lever. A thermal relief valve is incorporated in the design that bridges between the valve outlet and a port that empties into the center tank to prevent excessive pressure build-up due thermal expansion of the fuel in the fuel line following an APU shutdown. APPLICATIONS: Commercial aircraft FEATURES AND ATTRIBUTES: Parker Aerospace's APU feed shutoff valve has a corrosion resistant, lightweight construction that weighs less than 1.2 lb. The valve shares a design and fielded service legacy of similiar reliable Parker fuel ball valves that goes back decades, and awith a guaranteed mean time between failure (MTBF) of more than 57,590 flight hours. The APU feed shutoff valve is certified for conducted current lightning strikes, and use with all standard, available aviation fuels including Jet A, Jet A-1, JP-5, JP-8, and TS-1. It can operate between 0 and 40 psig of fuel pressure in the fuel line, at fuel temperatures between -58 degrees F and +160 degrees F, and ambient operating temperatures between -67 degrees F and +185 degrees F. Its operating time to open or close, when commanded, is between 2.5 and 8.5 seconds, depending on the actuator’s input voltage from the aircraft.