Low NO.sub.x gas burner apparatus and methods

An improved gas burner apparatus for discharging a mixture of fuel gas and air into a furnace space wherein said mixture is burned and flue gases having low NO.sub.x content are formed therefrom comprising:

• a housing having an open end attached to said furnace space;
• means for introducing a controlled flow rate of said air into said housing attached thereto;
• a refractory burner tile attached to the open end of said housing having an opening formed therein for allowing air to pass therethrough and having a wall surrounding said opening which extends into said furnace space, the exterior sides of said wall being slanted towards said opening and the interior sides thereof being spaced from the periphery of said opening whereby a ledge is provided within the interior of said wall;
• at least one passage in said burner tile for conducting primary fuel gas and flue gases from the exterior of said wall to the interior thereof;
• means for forming a fuel gas jet in said passage and drawing flue gases therethrough adapted to be connected to a source of fuel gas and positioned with respect to said passage whereby primary fuel gas and flue gases from said furnace space are discharged from said passage to within the interior of said wall;
• and
• at least one nozzle adapted to be connected to a source of fuel gas positioned outside said wall of said burner tile for discharging secondary fuel gas adjacent an external slanted side of said wall whereby said secondary fuel gas mixes with flue gases and air in said furnace space.