Fuel system pneumatic purge apparatus and method

Claim 3

A method as set forth in claim 1, further including the step of continuing flow of air from the accumulator through said fuel manifold after completion of combustion of said purged fuel to cleanse fuel nozzles in said combustion chamber of residual fuel traces to minimize carbon formation on said nozzles by heat breakdown of the fuel traces.

Claim 4

A method as set forth in claim 2, wherein said communicating step includes delivering air from the accumulator to said fuel manifold at a location in the manifold preventing leakage of fuel from upstream of said location into the combustion chamber subsequent to engine shutdown.

Claim 5

A method as set forth in claim 1 wherein said timing step includes substantially simultaneously initiating said interrupting step and said communicating step.

Claim 6

A method as set forth in claim 1 wherein the pressure in said accumulator substantially continually reduces during said communicating step.

Claim 7

A method as set forth in claim 1, further including the step of preventing reverse flow from the accumulator to the compressor during and subsequent to said engine speed reducing step.

Claim 8

A method as set forth in claim 6, further including the step of preventing communication between the accumulator and the fuel manifold prior to said communicating step.

Claim 9

A method as set forth in claim 1, further including the step of sizing the accumulator relative to the volume of the fuel to be purged from the manifold whereby the volume of gas delivered from the accumulator to the fuel manifold during said communicating step is sufficient to effect combustion of the purged fuel.

Claim 10

A method as set forth in claim 8, wherein said speed reducing step includes reducing the speed of the gas turbine engine to a level whereby the pressure of gas in the accumulator is approximately four times the pressure maintained in the combustion chamber, said sizing step including providing an accumulator whose volume is approximately three times the volume of fluid to be purged from the fuel manifold.

Claim 13

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.

Claim 14

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.

Claim 15

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.

Claim 16

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.

Claim 17

A combination as set forth in claim 12, wherein said conduit means communicates with said fuel manifold at a position gravitationally lower than said combustion chamber.

Claim 18

A combination as set forth in claim 12, further including a check valve disposed in said conduit means communicating said compressor discharge conduit with said accumulator preventing reverse flow from the accumulator toward said compressor discharge conduit;

Claim 19

A combination as set forth in claim 12, further including 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.

Claim 20

A combination as set forth in claim 12, wherein said fuel delivery system includes first and second fuel manifolds for delivering fuel to said combustion chamber, and a flow divider valve communicating with said pump and said first and second manifolds for dividing fuel flow from the pump between said first and second manifolds, said conduit means including first and second branches downstream of said shutoff valve respectively communicating said first and second manifolds in parallel relationship with said accumulator.

Claim 21

A combination as set forth in claim 12, wherein the ratio of the volume of said accumulator to the volume of the fuel manifold to be purged is approximately three to one.

Claim 22

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.

Claim 23

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.

Claim 24

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.

Claim 25

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.