A method of premixing apparatus for missing fuel gas with air to supply thus obtained air-fuel mixture, through a fan to a burner, includes at a time of changing over to a small-capacity state in which a first ventilation resistance in an air supply passage is increased and also in which a second ventilation resistance in a gas supply passage is increased, rotating a butterfly valve down to a closing side stop angle; and at a time of changing over to a large-capacity state in which the first ventilation resistance in the air supply passage is decreased and also in which the second ventilation resistance in the gas supply passage is decreased, rotating the butterfly valve up to an open-side stop angle.

A bottom cup cover, a burner and a gas appliance are provided. The bottom cup cover includes a gas intake assembly defining a first gas intake channel, a second gas intake channel, and a connecting channel connecting the first gas intake channel to the second gas intake channel. The second gas intake channel is obliquely arranged relative to the first gas intake channel. The first gas intake channel has a gas inlet. The bottom cup cover defines a first primary air supplement cavity and a second primary air supplement cavity separated from the first primary air supplement cavity. The first gas intake channel is in communication with the first primary air supplement cavity, the second gas intake channel is in communication with the second primary air supplement cavity, and the connecting channel is configured to enable a gas flow to circulate between the first and second primary air supplement cavities.

A low NO.sub.X air heating swirl burner includes at least one burner unit, the burner unit comprising a combustion air duct, a fuel gas supply pipeline, a combustion nozzle and a fire protection baffle. The fire protection baffle comprises a fin and a base plate for generating swirl combustion air. The base plate includes a plurality of elongated holes and air guide blades disposed obliquely on air outlet sides of the elongated holes. The combustion air flows out of the elongated holes in the base plate of the fire protection baffle, generates a rotational flow under the action of the air guide blades to be strongly mixed with fuel gas sprayed from the combustion nozzle for combustion. The burner is in a modular form, which can adopt a corresponding splicing shape according to structural features of a heating space to meet the heating requirement.

The present invention discloses a vortex pressurized burner. The vortex pressurized burner adopts a gradually reduced volute flow passage to make a pressure difference of a volute flow passage from a gas passage head end to a gas passage tail end smaller, so that the jetted gas is more uniform, increasing the uniformity of circumferential combustion of flames.

There is provided a system for consistent production of a low-or zero-emission flame comprising an electrolyser, a power assembly, a burner element, and a gas flow control system. There is also provided a device for consistent production of a low-or zero-emission flame using the disclosed systems. There is also provided a method for consistent production of a low-or zero-emission flame. There is further provided a kit for assembling, modifying or retrofitting an apparatus to permit consistent production of low-or zero-emission flame using the disclosed systems and methods.