Methods and systems for operating an engine coupled to a fuel system having at least one fuel manifold configured to supply fuel to a combustor of the engine are described. The method comprises, when the engine is active, supplying fuel to the combustor by supplying gaseous fuel from a gaseous fuel supply to the at least one fuel manifold, and when the engine is inactive, purging the at least one fuel manifold by supplying inert gas from an inert gas supply to the at least one fuel manifold.

A burner for a metal-melting furnace can releasably receive a tapered plug in sealing engagement with an access passage aligned with an air passage. The burner may be configured to extend through a wall of the metal-melting furnace so that the air passage is through a front face within the furnace and so that the access passage is through a rear face outside of the furnace. The access passage may be aligned with the air passage to permit a rigid structure to be passed through the burner from outside the furnace to dislodge build-up of solidified metal from the air passage. The tapered plug may be moveable between a sealing configuration of being received in a seat to seal the access passage during burner operation and a cleaning configuration of being removed from the seat to expose the access passage for insertion of the rigid structure.

A burner for a metal-melting furnace can releasably receive a tapered plug in sealing engagement with an access passage aligned with an air passage. The burner may be configured to extend through a wall of the metal-melting furnace so that the air passage is through a front face within the furnace and so that the access passage is through a rear face outside of the furnace. The access passage may be aligned with the air passage to permit a rigid structure to be passed through the burner from outside the furnace to dislodge build-up of solidified metal from the air passage. The tapered plug may be moveable between a sealing configuration of being received in a seat to seal the access passage during burner operation and a cleaning configuration of being removed from the seat to expose the access passage for insertion of the rigid structure.

A fuel system can include a first fuel circuit, a second fuel circuit, and an inert gas purge system operatively connected to both the first fuel circuit and the second fuel circuit to purge at least a portion of either or both of the first and/or second fuel circuit. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The first fuel circuit can include a first fuel manifold configured to fluidly communicate a first fuel supply with at least one dual fuel nozzles downstream of the first fuel manifold.

A fuel injector is disclosed for reducing flashback. In an embodiment, the fuel injector may comprise an injector head with purge holes on a radial wall along a radial axis between an assembly axis of the fuel injector and a plurality of vanes arranged circumferentially around the assembly axis. In addition, the plurality of vanes may comprise fuel outlets connecting interior fuel passages to spaces between the vanes. The introduction of these purge holes near the bases of the vanes and the configuration and positioning of the fuel outlets in the vanes and elsewhere in the fuel injector may alter the stoichiometry (e.g., fuel-air ratio) within the premix passage of the fuel injector to reduce flashback. A plurality of such fuel injectors may be used in the combustor of a gas turbine engine.

A multi-way valve includes an outer casing provided with an internal cavity, at least one input to the cavity, at least one output from the cavity, the at least one input having sealing means, and an actuator adapted to cause the opening of the sealing means of the inputs. A cross-section of the actuator is smaller than a cross-section of the inner cavity.

An internal fuel manifold assembly includes a fuel manifold ring having at least one fuel conveying passage in fluid flow communication with at least one inlet passage defined through an inlet member. The inlet member is connected to the manifold ring proximate its first end and connected proximate its second end to at least one transfer tube. The inlet member includes a drainage passage for collecting possible leaked fuel from an annulus, defined between the inlet member and a heat shield surrounding the inlet member and spaced apart therefrom. Any leaked fuel is discharged out of the inlet member at an exit of the fuel passage on an end surface of the inlet member proximate the second end thereof.

A combustor having a plurality of nozzles (main nozzles) to supply fuel disposed, includes a water supplier that is connected to all or part of the plurality of nozzles to supply water to each of fuel pipes, wherein the water supplier varies a supply amount of water for each of the nozzles to which the water is supplied.

A furnace includes a gas burner exposed to a heat-exchange tube. An inducer is fluidly coupled to the heat-exchange tube and configured to induce draft air through the heat-exchange tube. A regulator is fluidly coupled to the gas burner. A rollout shield is disposed adjacent to the gas burner. A rollout switch is disposed in the rollout shield. The rollout switch is electrically coupled to the regulator. At least one vent is formed through the rollout shield adjacent to the rollout switch. The vent provides a path for a rollout flame to the rollout switch. The at least one vent is disposed on at least two sides of the rollout switch.

A method and system for cleaning a fuel nozzle during engine operation is provided. Operations include operating the compressor section to provide the flow of oxidizer at a first oxidizer flow condition to the combustion chamber, wherein the first oxidizer flow condition comprises an environmental parameter; operating the fuel system at a first fuel flow condition to produce a fuel-oxidizer ratio at the combustion chamber; comparing the environmental parameter to a first environmental parameter threshold; and transitioning the fuel system to a second fuel flow condition corresponding to a cleaning condition at the fuel nozzle if the environmental parameter is equal to or greater than the first environmental threshold.