A premixing apparatus in which a downstream end of a gas supply passage is connected to a gas suction section disposed in an air supply passage on an upstream side of a fan, is provided with: a butterfly valve driven by a stepping motor, for changing over, between high and low, a ventilation resistance in that section of the air supply passage which is on an upstream side of the gas suction section; a changeover valve for changing over, between high and low, a ventilation resistance in that section of the gas supply passage which is on an upstream side of a flow control valve; and an interlocking mechanism which opens or closes the changeover valve in interlocking with the rotation of the butterfly valve and which maintains the changeover valve in a closed state until the butterfly valve has rotated from the closed posture toward the opening side by a predetermined angle. Flame failure and poor combustion are prevented at the time of changing over the butterfly valve and the changeover valve from closed posture to opened posture.

When the butterfly valve is rotated from the closed posture into the opened posture, a driving frequency of the stepping motor is made higher, until the butterfly valve has rotated from the closed posture toward the opening side by a predetermined set angle, than the driving frequency during the subsequent operation of the butterfly valve.

A modulating burner apparatus includes a burner and a blower placed upstream of the burner. A venturi is placed upstream of the blower. A damper valve is placed upstream of the venturi. The damper valve has an open position and a restricted position. A smaller gas valve and a larger gas valve are communicated with the venturi. A controller is operably associated with the system to select a position of the damper valve and to select the appropriate one of the gas valves so as to provide a low output operation mode and a high output operation mode, which in combination provide an overall turndown ratio of at least 25:1.

A system configured to generate heat when supplied with a first fuel or a second fuel can include a fuel supply line operatively connected to a fuel source. A valve assembly can be operatively connected to the fuel supply line. A main burner can be operatively connected to the valve assembly. A thermoelectric generating system can be configured to transform heat to electricity. A first pilot burner can include at least one of a first thermocouple and a first Fe-ion sensor. A second pilot burner can include at least one of a second thermocouple and a second Fe-ion sensor. A printed circuit board (PCB) can be operatively connected to the valve assembly and the first and second pilot burners. The PCB can be configured to control operation of the valve assembly based on information received from at least one of the first and second pilot burners.

A premixing apparatus for mixing air with a fuel gas to supply a burner with an air-fuel mixture via a fan includes: a zero governor and a motor-driven type of variable throttle valve, both being disposed in a gas supply passage; and an excess air ratio detecting device for detecting an excess air ratio of the air-fuel mixture, thereby regulating an opening degree of the variable throttle valve so that the excess air ratio of the air-fuel mixture becomes a predetermined value. An arrangement is made to prevent an ignition failure from occurring in an attempt to perform an ignition operation in a state in which, due to a trouble with the variable throttle valve of remaining opened or remaining closed, the excess air ratio of the air-fuel mixture becomes too small or too excessive. The variable throttle valve is provided with a sensing device.

A premixing apparatus has a butterfly valve provided in an air supply passage, a zero governor and a variable throttle valve interposed in a gas supply passage. A control is performed to switch a combustion capacity between at least two stages of a large-capacity stage and a small-capacity stage through change in opening degrees of the butterfly valve and the variable throttle valve. At the small-capacity time, in case the opening degree of the variable throttle valve, when regulated so that the λ becomes a predetermined value, has been changed more to the small-opening-degree side than the predetermined small-capacity opening degree, in a state in which the opening degree of the variable throttle valve has been returned to the predetermined small-capacity opening degree, the opening degree of the butterfly valve is regulated such that the λ becomes the predetermined value, and the small-capacity opening degree of the butterfly valve is renewed to the predetermined value when the λ becomes the predetermined value.

According to an embodiment, a burner system includes a pilot burner disposed in a furnace at a distal position along a main fuel and combustion air flow axis, and one or more main fuel nozzles disposed at a proximal position along the main fuel and combustion air flow axis. The pilot burner is configured to support a pilot flame and the one or more main fuel nozzles are configured to support a main flame in contact with the pilot flame. The pilot burner is disposed to cause the main fuel and combustion air to be ignited by the pilot flame. The pilot burner may support a diffusion pilot flame or may include a premixing apparatus to support a pre-mixed flame.

A gas fired burner control system for a kiln for firing for instance ceramic items. The system including a plurality of operating modes, with the system being configured such that during a firing cycle the system can move between operating in different modes.

The present disclosure seeks to provide a metallic burner tile for use in industrial processes such as cracking. The tile is substantially metallic (e.g. more than 80%) with the balance being ceramic coating on surfaces exposed to high temperature. The tile is lighter and more durable than the current ceramic burners.

An online pulverized coal concentration regulator is mounted at a front end of a pulverized coal pipe, and a pulverized coal concentration detector is arranged in the pipe. The regulator includes a control system, and an output of the concentration detector is connected with a signal input end of the control system. The regulator includes a top plate, a regulating rod, and a powder baffle plate. A mounting hole for fixedly mounting the front end of the pipe and a through hole for the powder baffle plate to penetrate through are arranged in the top plate, and a connector is arranged between the regulating rod and the powder baffle plate. The regulator includes a guider slidably connected with the powder baffle plate and fixedly connected with the top plate, and a diversion plate arranged on the top plate and slidably connected with the powder baffle plate.

In some examples, a method for operating a gas burner appliance includes determining, on basis of a nominal burner-load and on basis of a mixing ratio of gas and air of a gas/air mixture or a λ-value of the gas/air mixture, a nominal air mass flow in order to provide the nominal burner-load. The method further comprises determining the ambient air pressure and the ambient air temperature of the ambient air, determining, on basis of the ambient air pressure and on basis of the ambient air temperature, the atmospheric density of the ambient air, determining on basis of the nominal air mass flow, on basis of the determined atmospheric density of the ambient air, and on basis of a system resistance of the gas burner appliance, the fan speed of the fan in order to provide the nominal burner-load.