# US 2014/0196466 A1 · Methods and systems for operating gas turbine engines > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0196466 A1 - Document ID: US20140196466A1 - Status: Published application - Kind: A1 - Application number: 13/741,797 - Filed: 2013-01-15 - Published: 2014-07-17 - Earliest claimed: 2013-01-15 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Fabien Thibault Codron; John Edward Pritchard; Stanley Kevin Widener - Web page: https://patentgrep.com/patent/US20140196466A1 ## CPC - F02C 7/22: Fuel supply systems - F02C 7/228: Dividing fuel between various burners - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) ## Abstract Methods and systems for operating a gas turbine engine including a fuel delivery system and a plurality of combustor assemblies are provided. The fuel delivery system comprises a primary fuel circuit configured to continuously supply fuel to each of the plurality of combustor assemblies during a first mode of operation and a second mode of operation. At least one secondary fuel circuit of the fuel delivery system is configured to supply fuel to each of the plurality of combustor assemblies during the second mode of operation. The secondary fuel circuit includes at least one isolation valve coupled in flow communication with each of the plurality of combustor assemblies. The at least one isolation valve facilitates preventing fluid flow upstream into the secondary fuel circuit during the first mode of operation. The fuel delivery system, using the isolation valve, replaces a purging system in the gas turbine engine. ## Claims ### Claim 1 A fuel delivery system for a gas turbine engine including a plurality of combustor assemblies, said fuel delivery system comprising: a primary fuel circuit configured to continuously supply fuel to each of the plurality of combustor assemblies during a first mode of operation and a second mode of operation; and at least one secondary fuel circuit configured to supply fuel to each of the plurality of combustor assemblies during the second mode of operation, said secondary fuel circuit comprising at least one isolation valve coupled in flow communication with each of the plurality of combustor assemblies, said at least one isolation valve facilitates preventing fluid flow upstream into said secondary fuel circuit during said first mode of operation, wherein the gas turbine engine does not include a purging system. ### Claim 2 (depends on 1) The fuel delivery system in accordance with claim 1, wherein said at least one isolation valve is optionally a passively controlled check valve or an actively controlled actuated valve, wherein a controller is configured to control said actuated valve. ### Claim 3 (depends on 1) The fuel delivery system in accordance with claim 1, wherein said at least one isolation valve is optionally coupled to said secondary fuel circuit upstream and proximate to each of said plurality of combustor assemblies or said at least one isolation valve is integral to each of said plurality of combustor assemblies such that said at least one isolation valve is coupled to at least one secondary fuel nozzle within each of said plurality of combustor assemblies. ### Claim 4 (depends on 1) The fuel delivery system in accordance with claim 1, wherein said primary fuel circuit further comprises a primary manifold coupled to a primary staging valve, said secondary circuit further comprises a secondary manifold coupled to a secondary staging valve. ### Claim 5 (depends on 4) The fuel delivery system in accordance with claim 4, wherein said secondary staging valve is configured to selectively open during said first mode of operation to enable fuel to flow into said secondary manifold, and wherein each of said at least one isolation valve is configured to selectively close to prevent the flow of fuel from said secondary manifold to fuel to said plurality of combustor assemblies during said first mode of operation. ### Claim 6 (depends on 4) The fuel delivery system in accordance with claim 4, wherein said secondary staging valve configured to selectively open during said second mode of operation to enable fuel to flow to said secondary manifold, and wherein each of said at least one isolation valve is configured to selectively open to enable fuel to flow to each of said plurality of combustor assemblies through said secondary fuel circuit during said second mode of operation. ### Claim 7 (depends on 4) The fuel delivery system in accordance with claim 4, wherein said secondary staging valve is configured to selectively close to prevent the flow of fuel to said secondary manifold during a transition from said second mode of operation to said first mode of operation, and wherein each of said at least one isolation valve is configured to selectively close to prevent the flow of hot air or combustion products from said plurality of combustor assemblies to said secondary manifold. ### Claim 8 (depends on 7) The fuel delivery system in accordance with claim 7, wherein said secondary manifold is pressurized between said secondary staging valve and each isolation valve to a higher pressure than the operating pressure of the plurality of combustor assemblies to facilitate preventing upstream fluid flow into said secondary manifold. ### Claim 9 A method for controlling fuel flow in a gas turbine engine including a plurality of combustor assemblies, each of the combustor assemblies including at least one fuel circuit, wherein a fuel delivery system supplies each fuel circuit with fuel, said method comprising: supplying fuel to each of the plurality of combustor assemblies via a primary fuel circuit during a first mode of operation; and supplying fuel to each of the plurality of combustor assemblies via the primary fuel circuit and at least one secondary fuel circuit during a second mode of operation, wherein each of the at least one secondary fuel circuits comprises at least one isolation valve coupled in flow communication with each of the plurality of combustor assemblies, wherein each of the isolation valve facilitates preventing fluid flow upstream into the secondary fuel circuit during the first mode of operation, wherein the gas turbine engine does not include a purging system. ### Claim 10 (depends on 9) The method in accordance with claim 9, the fuel delivery system further including a plurality of staging valves and manifolds, said method further comprising: opening a primary staging valve to enable fuel to flow to the plurality of combustor assemblies through a primary manifold during the first mode of operation; opening a secondary staging valve to enable fuel to flow into a secondary manifold during the first mode of operation; and closing each isolation valve to prevent the flow of fuel to the plurality of combustor assemblies through the secondary manifold during the first mode of operation. ### Claim 11 (depends on 9) The method in accordance with claim 9, the fuel delivery system further including a plurality of staging valves and manifolds, said method further comprising: opening a primary staging valve to enable fuel to flow to the plurality of combustor assemblies through the primary manifold during the second mode of operation; opening a secondary staging valve to enable fuel to flow to the secondary manifold during the second mode of operation; and opening each isolation valve to enable fuel to flow to the plurality of combustor assemblies through the secondary manifold during the second mode of operation. ### Claim 12 (depends on 9) The method in accordance with claim 9, the fuel delivery system further including a plurality of staging valves and manifolds, said method further comprising: opening a primary staging valve to enable fuel to flow to the plurality of combustor assemblies through the primary manifold during a transition from the second mode of operation to the first mode of operation; closing a secondary staging valve to prevent the flow of fuel to the secondary manifold during a transition from the second mode of operation to the first mode of operation; and closing each isolation valve to prevent the flow of hot combustion gases from the plurality of combustor assemblies into the secondary fuel manifold during a transition from the second mode of operation to the first mode of operation. ### Claim 13 (depends on 12) The method in accordance with claim 12 further comprising pressurizing the secondary manifold between the secondary staging valve and each isolation valve to a higher pressure than the operating pressure of the plurality of combustor assemblies to facilitate preventing fluid flow upstream into the secondary manifold during the first mode of operation. ### Claim 14 (depends on 12) The method in accordance with claim 12 further comprising venting the secondary manifold between the secondary staging valve and each of the isolation valves to remove gases from the secondary manifold. ### Claim 15 A gas turbine engine assembly comprising: a plurality of combustor assemblies; a primary fuel circuit configured to continuously supply fuel to each of said plurality of combustor assemblies during a first mode of operation and a second mode of operation; and at least one secondary fuel circuit configured to supply fuel to each of said plurality of combustor assemblies during said second mode of operation, said secondary fuel circuit comprising at least one isolation valve coupled in flow communication with each of said plurality of combustor assemblies, said at least one isolation valve facilitates preventing fluid flow upstream into said secondary fuel circuit during said first mode of operation, wherein the gas turbine engine does not include a purging system. ### Claim 16 (depends on 15) The gas turbine engine assembly in accordance with claim 15, wherein said at least one isolation valve is optionally a passively controlled check valve or an actively controlled actuated valves, wherein a controller is configured to control said actuated valves. ### Claim 17 (depends on 15) The gas turbine engine assembly in accordance with claim 15, wherein said at least one isolation valve is optionally coupled to said secondary fuel circuit upstream and proximate to each of said plurality of combustor assemblies or said at least one isolation valve is integral to each of said plurality of combustor assemblies such that said at least one isolation valve is coupled to at least one secondary fuel nozzle within each of said plurality of combustor assemblies. ### Claim 18 (depends on 15) The gas turbine engine assembly in accordance with claim 15 further comprising a plurality of staging valves and manifolds, wherein a primary staging valve is configured to open during said first mode of operation to enable fuel to flow to each of said plurality of combustor assemblies through a primary manifold, and wherein a secondary staging valve is configured to selectively open during said first mode of operation to enable fuel to flow to a secondary manifold, and wherein each of said at least one isolation valve is configured to close to prevent the flow of fuel from said secondary manifold to the plurality of combustor assemblies during said first mode of operation. ### Claim 19 (depends on 15) The gas turbine engine assembly in accordance with claim 15 further comprising a plurality of staging valves and manifolds, wherein a primary staging valve is configured to open during said second mode of operation to enable fuel to flow to each of said plurality of combustor assemblies through a primary manifold, and wherein a secondary staging valve is configured to open during said second mode of operation to enable fuel to flow to a secondary manifold, and wherein each of said at least one isolation valve is configured to selectively open to enable fuel to flow to the plurality of combustor assemblies through said secondary fuel circuit during said second mode of operation. ### Claim 20 (depends on 15) The gas turbine engine assembly in accordance with claim 15 further including a plurality of staging valves and manifolds, wherein a primary staging valve is configured to remain open during a transition from said second mode of operation to said first mode of operation to enable fuel to flow to each of said plurality of combustor assemblies through a primary manifold, and wherein a secondary staging valve is configured to close to prevent the flow of fuel to a secondary manifold during a transition from said second mode of operation to said first mode of operation, and wherein each of said at least one isolation valve is configured to selectively close to prevent the flow of hot combustion products from the plurality of combustor assemblies into said secondary manifold.