Burner with low NOx emissions

A burner for the combustion of fuel in a furnace, said burner comprising:

• (a) a burner tube having an upstream end, a downstream end and a venturi intermediate said upstream and downstream ends, said venturi including a throat portion having substantially constant internal cross-sectional dimensions such that the ratio of the length to maximum internal cross-sectional dimension of said throat portion is at least 3;
• (b) a burner tip adjacent a first opening in the furnace, so that combustion of the fuel takes place downstream of said burner tip;
• (c) a lighting chamber adjacent to the first opening in the furnace;
• and
• (d) a removable lighting chamber plug having a shape effective to substantially fill said lighting chamber when positioned within said lighting chamber.

A burner for the combustion of fuel in a furnace, said burner comprising:

• (a) a burner tube having a longitudinal axis and having a downstream end and an upstream end for receiving fuel and air, flue gas or mixtures thereof;
• (b) a fuel orifice located adjacent the upstream end of said burner tube, for introducing fuel into said burner tube;
• (c) means including a plate for centering said fuel orifice in alignment with said burner tube, said centering plate being perforated to permit flow therethrough from said primary air chamber
• (d) a burner tip mounted on the downstream end of said burner tube and adjacent a first opening in the furnace, said burner tip having a plurality of main ports substantially aligned with said longitudinal axis of the burner tube, and a plurality of peripherally arranged side ports;
• and
• (e) a peripheral tile which peripherally surrounds said burner tip, said peripheral tile providing at least one gap between an outer periphery of said burner tip and said peripheral tile, said at least one gap effective for providing a portion of the air for combustion
• wherein the quantity of fuel discharged during combustion from said peripherally arranged side ports does not exceed 15% of the total fuel combusted.