Abstract: Improved apparatus for burning fuel with low NOx formation are provided. An apparatus of the invention for discharging a mixture of fuel gas and air into a furnace wherein the mixture is burned and flue gases having a low NOx content are formed includes the following. A burner housing, attached to a furnace, is provided having a means for mixing a first portion of the fuel gas with a first portion of the air to form a primary fuel gas-air mixture and discharging the primary fuel gas-air mixture into a primary burning zone in the furnace from at least one discharge location surrounded by a wall which extends into the furnace. A means for mixing a second portion of the fuel with a second portion of the air to form a secondary fuel gas-air mixture is also provided whereby the secondary fuel gas-air mixture is discharged into a secondary burning zone in the furnace from at least one discharge location adjacent to an exterior side of the wall.

Abstract: Improved apparatus for burning fuel with low NOx formation are provided. An apparatus of the invention for discharging a mixture of fuel gas and air into a furnace wherein the mixture is burned and flue gases having a low NOx content are formed includes the following. A burner housing, attached to a furnace, is provided having a means for mixing a first portion of the fuel gas with a first portion of the air to form a primary fuel gas-air mixture and discharging the primary fuel gas-air mixture into a primary burning zone in the furnace from at least one discharge location surrounded by a wall which extends into the furnace. A means for mixing a second portion of the fuel with a second portion of the air to form a secondary fuel gas-air mixture is also provided whereby the secondary fuel gas-air mixture is discharged into a secondary burning zone in the furnace from at least one discharge location adjacent to an exterior side of the wall.

Abstract: Improved methods and apparatus for burning fuel with low NOx formation are provided. A method of the invention for discharging a mixture of fuel gas and air into a furnace wherein the mixture is burned and flue gases having a low NOx content are formed includes the following steps. A first portion of the fuel gas is mixed with a first portion of the air to form a primary fuel gas-air mixture. The primary fuel gas-air mixture is discharged into a primary burning zone in the furnace from at least one discharge location surrounded by a wall which extends into the furnace. A second portion of the fuel and a second portion of the air are mixed to form a secondary fuel gas-air mixture. The secondary fuel gas-air mixture is discharged into a secondary burning zone in the furnace from at least one discharge location adjacent to an exterior side of the wall.

Abstract: Improved methods and apparatus for burning fuel with low NOx formation are provided. A method of the invention for discharging a mixture of fuel gas and air into a furnace wherein the mixture is burned and flue gases having a low NOx content are formed includes the following steps. A first portion of the fuel gas is mixed with a first portion of the air to form a primary fuel gas-air mixture. The primary fuel gas-air mixture is discharged into a primary burning zone in the furnace from at least one discharge location surrounded by a wall which extends into the furnace. A second portion of the fuel and a second portion of the air are mixed to form a secondary fuel gas-air mixture. The secondary fuel gas-air mixture is discharged into a secondary burning zone in the furnace from at least one discharge location adjacent to an exterior side of the wall.

Abstract: An improved low NOx burner assembly having a burner plate assembly which is attached to a burner head portion thereof, the burner plate assembly having a burner plate and a wrapper, the burner plate having a relatively large central aperture and a plurality of smaller apertures of several diametrical sizes disposed at selected radial positions. The burner plate, attached to the burner head portion of the burner assembly via its wrapper, partially closes the outlet end of the burner head, and flame combustion is partially contained in a premixing chamber, thus effecting prolonged contact with combustion air prior to the gas and air mixture passing through the apertures of the burner plate.

Abstract: An opposed louver air damper apparatus for controlling the flow rate of combustion air to a burner fire box, comprising a plurality of adjacent, rotatable louvers having rubber tips and side gaskets providing sealing between the louvers and a frame, and geared responsive shafts supporting the louvers for controllably rotating the louvers to determinative positions to modulate the volume of air passing through the louver apparatus, wherein the gears in meshing engagement precisely maintains the relative position of the louvers, and the gaskets operate to minimize undesirable leakage through the air damper. The gears form teeth in arcuate portions of the full circumference to limit the rotational movement to only that within the toothed portion of the gear.