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US 4,394,811 AGranted
Fuel control for gas turbine with continuous pilot flame
AssigneeGeneral Motors Corporation
InventorRobert M. Swick
Life of this patent
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AssigneeGeneral Motors Corporation
InventorRobert M. Swick
Estimating the term…
An improved fuel control for a gas turbine engine having a continuous pilot flame and a fuel distribution system including a pump drawing fuel from a source and supplying a line to the main fuel nozzle of the engine, the improvement being a control loop between the pump outlet and the pump inlet to bypass fuel, an electronically controlled throttle valve to restrict flow in the control loop when main nozzle demand exists and to permit substantially unrestricted flow without main nozzle demand, a minimum flow valve in the control loop downstream of the throttle valve to maintain a minimum pressure in the loop ahead of the flow valve, a branch tube from the pilot flame nozzle to the control loop between the throttle valve and the minimum flow valve, an orifice in the branch tube, and a feedback tube from the branch tube downstream of the orifice to the minimum flow valve, the minimum flow valve being operative to maintain a substantially constant pressure differential across the orifice to maintain constant fuel flow to the pilot flame nozzle.
In a fuel system for a gas turbine engine of the type having a main nozzle means and continuous pilot flame nozzle means, said fuel system including a source of fuel, positive displacement pump means, fuel inlet means between said fuel source and said pump means, and distribution means between said pump means and said main nozzle means for directing pressurized fuel to said main nozzle means, the improvement comprising, means defining a control loop between said distribution means and said inlet means operative to bypass pressurized fuel back to said inlet means, throttle valve means disposed in said control loop operative to restrict fuel bypass flow in proportion to main nozzle means demand and to permit substantially unrestricted bypass flow at minimum main nozzle means demand, minimum flow valve means in said control loop downstream of said throttle valve means operative to maintain a minimum pressure in said control loop ahead of said minimum flow valve means, branch tube means connected to said continuous pilot flame nozzle means and to said control loop between said throttle valve means and said minimum flow valve means for directing fuel to said continuous pilot flame means, and pressure compensating means in said minimum flow valve means operative to increase the pressure in said control loop ahead of said minimum flow valve and in said branch line in proportion to a control parameter of said gas turbine engine.
In a fuel system for a gas turbine engine of the type having a main nozzle means and continuous pilot flame nozzle means, said fuel system including a source of fuel, positive displacement pump means, fuel inlet means between said fuel source and said pump means, and distribution means between said pump means and said main nozzle means for directing pressurized fuel to said main nozzle means, the improvement comprising, means defining a control loop between said distribution means and said inlet means operative to bypass pressurized fuel back to said inlet means, throttle valve means disposed in said control loop operative to restrict fuel bypass flow in proportion to main nozzle means demand and to permit substantially unrestricted bypass flow at minimum main nozzle means demand, minimum flow valve means in said control loop downstream of said throttle valve means operative to maintain a minimum pressure in said control loop ahead of said minimum flow valve means, branch tube means connected to said continuous pilot flame nozzle means and to said control loop between said throttle valve means and said minimum flow valve means for directing fuel to said continuous pilot flame nozzle means, means in said branch tube means defining a flow restricting orifice adapted to pass fuel at a preselected rate when a pressure differential or predetermined magnitude exists across said orifice, feedback tube means between said branch tube means downstream of said orifice and said minimum flow valve means operative to feedback the pressure in said branch tube to said minimum flow valve means, and means in said minimum flow valve means operative in response to the pressure in said feedback tube means to increase the pressure in said control loop ahead of said minimum flow valve means and in said branch tube means ahead of said orifice in proportion to an increase in presence in said feedback tube means thereby to maintain a substantially constant pressure differential across said orifice.
Dependencies are inferred from the claim text.