Patent ID: 8104258

Claim:
A metering purge valve for use in a turbine fuel system, comprising: a valve body defining a valve passageway in communication with a purge air inlet, a fuel inlet and a fuel outlet; and a spool movable along a spool axis within the valve passageway, the spool having a metering surface for metering flow from the fuel inlet to the fuel outlet and an interchange providing communication through the spool from the fuel inlet to the metering surface of the spool; wherein the spool is movable from a first position in which the purge air inlet and the fuel inlet are essentially closed off from the fuel outlet, to a second position in which the fuel inlet is open to, and the purge air inlet is essentially closed off from, the fuel outlet to a third position in which the fuel inlet is essentially closed off from, and the purge air inlet is open to, the fuel outlet.