Fuel system pneumatic purge apparatus and method
AssigneeThe Garrett Corporation
InventorsJohn Everett Harper, Louis H. Kell
Life of this patent
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Abstract
A pneumatic purge system retrofittable upon existing gas turbine engines which includes an accumulator for storing pressurized gas at the maximum pressure developed by the compressor of the turbine engine. Upon actuating a solenoid fuel shutoff valve to initiate engine shutdown, stored gas from the accumulator flows into the fuel manifold to purge fuel therefrom into the combustion chamber. Timing of the pneumatic purging sustains the combustion process to burn substantially all the purged fuel.
Claims19
A method of purging fuel from the fuel delivery system in a gas turbine engine upon shutdown of the engine, comprising the steps of:
- bleeding air from the discharge of the compressor of the engine during substantially full speed operation;
- storing said bleed air in a pneumatic accumulator;
- reducing engine speed to reduce pressure in the combustion chamber of the engine to a value substantially less than that of bleed air stored in the accumulator;
- interrupting flow of fuel being delivered through a fuel manifold to the combustion chamber;
- communicating said accumulator with said fuel manifold after said engine speed reducing step to purge fuel from the manifold into the combustion chamber;
- and
- relatively timing said interrupting step and said communicating step whereby the combustion process in the combustion chamber is maintained subsequent to initiation of said communicating step such that fuel purged from the manifold is burned.
A method of retrofitting a gas turbine engine to provide purging of fuel manifold delivering liquid fuel to a combustion chamber of the engine, said engine having a bleed air port communicating with the compressor discharge passage of the engine for providing anti-icing, heated air flow to the inlet of the engine, said engine further having a solenoid operated fuel shut-off valve and a drain port communicating with the fuel manifold for normally draining liquid fuel therefrom upon shutdown of the engine, said method comprising the steps of:
- operably interconnecting a pneumatic accumulator with said bleed air port whereby gas at compressor discharge pressure developed during substantially maximum engine speed operation is stored in the accumulator;
- interconnecting the accumulator with said drain port;
- interposing a solenoid operated purge shutoff valve between the accumulator and said drain port for selectively blocking and allowing communication therebetween;
- and
- electrically interconnecting the solenoid of said purge shutoff valve with the solenoid of the fuel shutoff valve whereby upon actuation of said fuel shutoff valve to block fuel flow to said manifold, the purge shutoff valve is energized in relative timing to closing of the fuel shutoff valve to allow communication between the accumulator and the drain port to force fuel in the manifold into the combustion chamber in a manner maintaining combustion therein for substantially complete burning of the purged fuel.
In combination with a gas turbine engine having a compressor for compressing gas to an elevated pressure, and a compressor discharge conduit delivering pressurized gas to a combustion chamber:
- a fuel delivery system including a source of pressurized fuel and a fuel manifold supplying the pressurized fuel to the combustion chamber;
- means for interrupting fuel flow to said manifold when actuated;
- a gas accumulator operably communicating with said compressor discharge conduit whereby gas at substantially maximum compressor discharge pressure is stored in the accumulator;
- conduit means providing communication between said accumulator and said fuel manifold;
- a control valve operably disposed in said conduit means for selectively allowing and blocking gas flow from said accumulator to said manifold;
- and
- a one-way check valve disposed in said conduit means between said shutoff control valve and said fuel manifold for preventing reverse flow from the fuel manifold toward the accumulator.
In combination with a gas turbine engine having a compressor for compressing gas to an elevated pressure, and a compressor discharge conduit delivering pressurized gas to a combustion chamber:
- a fuel delivery system including a source of pressurized fuel and a fuel manifold supplying the pressurized fuel to the combustion chamber;
- means for interrupting fuel flow to said manifold when actuated;
- a gas accumulator operably communicating with said compressor discharge conduit whereby gas at substantially maximum compressor discharge pressure is stored in the accumulator;
- conduit means providing communication between said accumulator and said fuel manifold;
- a shutoff control valve operably disposed in said conduit means for selectively allowing and blocking gas flow from said accumulator to said manifold;
- and
- control means for actuating said shutoff control valve to allow purging gas flow to said manifold in timed relationship to actuation of said fuel flow interrupting means whereby fuel is purged from said manifold and burned in said combustion chamber.
A fuel purge system adapted for use with a fuel delivery system delivering fuel flow to the combustion chamber of an engine having means for developing pressurized gas flow to the combustion chamber in relation to speed of operation of the engine, said purge system comprising:
- a pneumatic accumulator adapted to communicate with said gas flow pressurizing means whereby gas is stored in the accumulator at substantially maximum pressure developed by the engine;
- means extending from said accumulator and adapted to communicate with said fuel delivery system;
- and
- control valve means operably disposed in said last mentioned means for selectively allowing and prohibiting gas flow from the accumulator through said last mentioned means to the fuel delivery system independently of pressure of said gas flow.
A gas turbine engine, comprising:
- means defining a gas flow inlet;
- compressor means for compressing gas received from inlet;
- a compressor discharge conduit for carrying compressed gas flow from the compressor;
- a combustion chamber for receiving compressed air flow from the compressor discharge conduit;
- a source of pressurized liquid fuel flow;
- a flow divider valve communicating the outlet of said source for dividing fuel flow into first and second streams;
- first and second fuel manifolds for receiving and respectively delivering said first and second streams of fuel flows to said combustion chamber to maintain a continuous combustion process in the combustion chamber during operation of said engine to heat gas delivered thereto;
- a gas accumulator;
- a first conduit extending between said pressure discharge conduit and said accumulator for delivering gas flow to the latter;
- a one-way check valve disposed in said first conduit for preventing reverse fluid flow from the accumulator to the compressor discharge conduit;
- a second conduit extending between said accumulator and said first and second fuel manifolds;
- check valve means disposed in said second conduit for preventing reverse flow from said manifolds towards said accumulator;
- a solenoid operated fuel shutoff valve operably communicating with said source of pressurized fluid for selectively allowing and blocking fuel flow to said manifolds;
- a solenoid operated gas shutoff control valve in said second conduit operable to selectively allow and block gas flow from the accumulator to said manifold;
- and
- control means operably coupled with said solenoid valves for substantially simultaneously actuating the latter to block fuel flow to said manifolds while allowing gas flow from the accumulator to said manifolds, said control means operable to time said actuation of the solenoid valves whereby fuel in said manifolds is purged therefrom into said combustion chamber while the combustion process therein continues such that substantially all said purged fuel is burned.
Dependencies are inferred from the claim text.