Cooktop appliances are provided. A cooktop appliance can include a manifold having a gas input; a first burner in fluid communication with the manifold through a first burner supply line having a first valve; and a second burner in fluid communication with the manifold through a second burner supply line having a second valve, the second burner arranged coaxially with respect to the first burner, wherein the second burner supply line comprises a primary line, a secondary line, and a sum line, the sum line providing a combined flow of gas from the primary line and the secondary line to the second burner, wherein the secondary line of the second burner comprises a third valve.

A novel inline pilot assembly and method of flame detection for use with combustion applications for oil or gas processing is provided wherein the pilot assembly includes a pilot novel assembly with a unique placement of fuel and induction holes to improve flame stability, promote flame anchoring near the diffuser, and discourage the pilot flame front from migrating forward away from the diffuser.

A novel inline pilot assembly and method of flame detection for use with combustion applications for oil or gas processing is provided wherein the pilot assembly includes a pilot novel assembly with a unique placement of fuel and induction holes to improve flame stability, promote flame anchoring near the diffuser, and discourage the pilot flame front from migrating forward away from the diffuser.

The method is used for detecting one failure in a burner of a combustor of a turbine system; the combustor comprises a plurality of burners arranged annularly; the turbine system comprises a turbine downstream of the combustor, the method comprising the steps of: A) providing a plurality of temperature sensors arranged annularly at the outlet of the turbine, B) detecting a plurality of temperatures through the plurality of temperature sensors, C) calculating a temperature spread indicator as a function of the plurality of temperatures, and D) carrying out a comparison the temperature spread indicator and a threshold; a positive result of this comparison indicates a burner failure.

A gas appliance includes a burner, a gas valve, and a control device, wherein the gas valve includes a valve body, a flow regulator, a hot film anemometer, and a stepper motor. The valve body communicates with the burner and a gas source. The flow regulator is driven by the stepper motor to change a gas flow rate supplying to the burner. The hot film anemometer is disposed in the valve body and includes a probe exposed to the outlet passage. The control device executes a control method for the gas valve: sensing the gas flow rate in the outlet passage with the hot film anemometer; comparing the gas flow rate sensed by the hot film anemometer with a predetermined gas flow rate, and controlling the stepper motor to drive the flow regulator based on the comparison result, whereby to stabilize the gas flow rate.

Described is a device for controlling a fuel-oxidizer mixture for a premix gas burner, comprising an intake duct, which defines a cross section for the passage of a fluid inside the duct and includes an inlet, a mixing zone and an outlet, an injection duct, connected to the intake duct in the mixing zone, a monitoring device, configured for generating a control signal, representing a combustion state in the burner, a gas regulating valve, positioned along the injection duct, a fan, positioned in the intake duct for generating therein an operating flow in an inflow direction, a control unit, configured to control the rotation speed of the fan, a regulator, coupled with the intake duct for varying the cross section. The control unit is configured for controlling the gas regulating valve in real time.

An air preheater (APH) temperature control system, including at least a first APH or combustion/secondary air bypass duct in metered communication with a combustion air inlet duct and a secondary air duct, adapted in use to bleed a portion of the combustion air as secondary air bypass from the air inlet duct upstream of the APH 100 for reintroduction downstream into the secondary air duct, and a flow control device for metering or controlling volumetric flow of the secondary air bypass and tempering primary air flow in use operative to maintain the flue gas outlet temperature at or above a desired minimum predetermined temperature for the incident flue gas volumetric flow exiting the APH alone or in conjunction with other tempering means maintaining mills outlet temperature within a safety range of T10.sub.MIN to T10.sub.MAX.

An air preheater (APH) temperature control system, including at least a first APH or combustion/secondary air bypass duct in metered communication with a combustion air inlet duct and a secondary air duct, adapted in use to bleed a portion of the combustion air as secondary air bypass from the air inlet duct upstream of the APH 100 for reintroduction downstream into the secondary air duct, and a flow control device for metering or controlling volumetric flow of the secondary air bypass and tempering primary air flow in use operative to maintain the flue gas outlet temperature at or above a desired minimum predetermined temperature for the incident flue gas volumetric flow exiting the APH alone or in conjunction with other tempering means maintaining mills outlet temperature within a safety range of T10.sub.MIN to T10.sub.MAX.

To heat a furnace chamber (16) indirectly using radiant tubes (11) to (14), heating energy is transferred through the radiant tube wall into the furnace chamber (16). During steady-state operation, the temperature in the radiant tube (11) to (14) and on its surface is higher than the furnace, depending on the specific heat output of the radiant tube (11) to (14). At a furnace temperature of 770 C. and a heat output of 50 kW/m2, the radiant tube has a temperature of 900 C. The radiant tube (11) to (14) can thus operate continuously with flameless oxidation at this output, even though the temperature in the furnace is only 100 C. However, if the radiant tube (11) to (14) has cooled to the furnace temperature of 770 C. during a break in burning, deflagration is avoided when the associated burner is ignited by initially operating said burner with a flame for a few seconds.

To heat a furnace chamber (16) indirectly using radiant tubes (11) to (14), heating energy is transferred through the radiant tube wall into the furnace chamber (16). During steady-state operation, the temperature in the radiant tube (11) to (14) and on its surface is higher than the furnace, depending on the specific heat output of the radiant tube (11) to (14). At a furnace temperature of 770 C. and a heat output of 50 kW/m2, the radiant tube has a temperature of 900 C. The radiant tube (11) to (14) can thus operate continuously with flameless oxidation at this output, even though the temperature in the furnace is only 100 C. However, if the radiant tube (11) to (14) has cooled to the furnace temperature of 770 C. during a break in burning, deflagration is avoided when the associated burner is ignited by initially operating said burner with a flame for a few seconds.