Staging valve arrangement and valve for use therein
A staging valve arrangement is described that comprises an arrangement of electrically driven staging valves that are located, in use, in the high temperature core zone of an engine. Each staging valve may comprise a housing having an inlet, a pilot flow outlet and a mains flow outlet, a valve member movable between a closed position in which the mains flow outlet is closed and an open position in which the mains flow outlet is open, a motor operable to drive the valve member for movement, and a cooling arrangement.
1. A gas turbine configured with a staging valve comprising a housing having an inlet, a pilot flow outlet which is configured to feed fuel to a pilot burner of the gas turbine, a first mains flow outlet which is configured to feed fuel to a main burner of the gas turbine, and a second mains flow outlet which is configured to feed fuel to the main burner, a valve member, a motor operable to drive the valve member for movement, and a cooling arrangement, wherein the valve member is movable by the motor between a closed position in which the first and second mains flow outlets are closed, an intermediate position in which the first mains flow outlet is open and the second mains flow outlet is closed, and a fully open position in which the first and second mains flow outlets are open.
2. A staging valve according to claim 1 , wherein the motor is one of an electric stepper motor and a piezo electric device.
3. A staging valve according to claim 1 , wherein the cooling arrangement comprises a flow passage through or adjacent to at least part of the motor and through which relatively cool fuel passes, in use.
4. A staging valve according to claim 1 , wherein the housing further includes a pilot flow passage along which fuel from the pilot flow outlet flows, in use, the fuel flow along the pilot flow passage serving to cool at least part of the housing, thus forming at least part of the cooling arrangement.
5. A staging valve according to claim 1 , further comprising high temperature electronics to provide localised closed loop control of the staging valve.
6. A staging valve arrangement comprising an arrangement of the staging valves of claim 1 that are located, in use, in the high temperature core zone of an engine.
7. An arrangement according to claim 6 , wherein each staging valve is integrated into the design of a corresponding burner assembly located on the engine combustor.
8. An arrangement according to claim 6 , further comprising a staging control unit operable to control the operation thereof.
9. An arrangement according to claim 6 , wherein high temperature electronics are integrated into the design of one or more of the staging valves to provide localised closed loop control of each individual staging valve.