Importance

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Abstract

A low NO.sub.x burner includes a burner plate having a plurality of slots from which fuel gas jets and combustion air are discharged. A plurality of fuel tubes are aligned with the slots for discharging the fuel gas therethrough. The fuel tubes are spaced from the slots so that combustion air, provided by a wind box, also can flow through the slots. The fuel gas and combustion air are discharged at high velocity, thereby generating very high turbulence in the combustion chamber downstream from the burner. The slots are arranged such that the width of the recirculation zones between adjacent slots substantially varies between the central region of the burner plate and its perimeter. With this construction, the local ignition patterns vary such that local oscillations of flame front occur at different frequencies and are not synchronized so that vibrations are greatly dampened and resonance problems in the furnace minimized or eliminated. Preferably a gas nozzle is arranged at the center of the burner plate and is provided with fuel gas discharge ports to direct fuel gas in a direction tangential to the nozzle so as to induce gas exiting therefrom to swirl downstream from the burner plate. A spinner also is arranged around this central gas nozzle to cause combustion air channeled around the nozzle to swirl downstream from the nozzle. In this way, flame stability without air preheat is achieved with up to 110% excess air.

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First Claim