Low nox burner

A fluid fuel burner designed to produce minimum quantities of NOx, comprising:

• a. a nozzle for injection of fuel into a first combustion zone surrounded by a first ceramic tile, and means to supply said fuel under pressure to said nozzle;
• b. means adjacent said nozzle to supply a limited volume of primary air in the region of said nozzle, the volume being insufficient for complete combustion of said fuel;
• c. an enclosure means surrounding and spaced from said first ceramic tile to define a first annular space communicating the outlet of said first combustion zone with the region of said nozzle;
• d. means to recirculate a portion of the products of combustion from said first combustion zone around the outside of said first tile through said annular space to the vicinity of said nozzle;
• e. a cylindrical wall annularly spaced from and surrounding said enclosure, said wall having openings therein to supply therethrough air, a portion of which becomes said volume of primary air, a remaining and larger portion being secondary air;
• f. means to supply said secondary air in heat exchange relation with the outside of said enclosure means to cool said recirculated products thence to a second combustion zone downstream from said first combustion zone, the quantity of secondary air being sufficient to theoretically completely combust said fuel, said second zone surrounded by second ceramic tile;
• g. a second annular space surrounding said second tile in communication with the outlet of said second combustion zone;
• and
• h. means to supply tertiary air to said outlet of said second combustion zone via said second annular space.