Abstract: A U-tube diffusion flame burner assembly having improved flame stabilization with no undesirable acoustic effects. The burners are axial units comprised of flame holders and combustors. The flame holders includes secondary air tubes to support the flow of secondary air that have helical walls forming helical passageways along at least a portion of its inner diameter to impart a swirl to the secondary air. The helical passageways impart a swirl to the secondary air exiting the passageways while simultaneously acting as a heat exchanger to heat primary air. The flame holders includes fuel tubes having first ends connected to a fuel supply and second flame ends. A plurality of radially oriented apertures are located at the second flame ends to distribute fuel in a radial direction. Primary air tube surrounds at least the flame ends of the fuel tubes and extend axially from first air supply ends to second flame ends.

Abstract: A U-tube diffusion flame burner assembly having improved flame stabilization with no undesirable acoustic effects. The burners are axial units comprised of flame holders and combustors. The flame holders includes secondary air tubes to support the flow of secondary air that have helical walls forming helical passageways along at least a portion of its inner diameter to impart a swirl to the secondary air. The helical passageways impart a swirl to the secondary air exiting the passageways while simultaneously acting as a heat exchanger to heat primary air. The flame holders includes fuel tubes having first ends connected to a fuel supply and second flame ends. A plurality of radially oriented apertures are located at the second flame ends to distribute fuel in a radial direction. Primary air tube surrounds at least the flame ends of the fuel tubes and extend axially from first air supply ends to second flame ends.

Abstract: A combination burner for selectively firing oil, natural gas and liquid propane. A modular first section has primary and secondary air tubes coaxially arranged therein and communicates with the main combustion air supply fan. A modular section is joined by bolts or the like to the first section and into which the primary and secondary air tubes extend. A center air spin vane rack is upstream of the secondary air tube in the first section. An adjustable spin vane rack is located radially outwardly of the secondary air tube for selectively spinning the main combustion air for flame adjustability. An air diverter is provided at a downstream end of the primary air tube. A compressed air atomizer is also at the downstream end of the primary air tube.

Abstract: A method and apparatus for adjusting the flame exit velocity of a high velocity burner. The burner includes burner combustor chamber having a fluid accelerating nozzle and a burner combustor exhaust port. Fuel is delivered to the burner combustor through a fuel inlet. An ignitor is provided to initiate combustion of the fuel which is mixed with air from an air inlet. An adjusting device is provided to vary the flame exit area of the burner. The adjusting device includes an adjusting rod connected to an extension rod which preferably extends through the burner ignition chamber to the burner combustion exit port. For example, a tapered plug is attached to the end of the extension rod. The tapered plug is tapered in a direction decreasing toward the burner combustion exit port and can include fins attached around a periphery of the plug.

Abstract: A radiant tube burner assembly and method is provided to reduce nitrous oxides and carbon monoxide emissions in the combustion of hydrocarbon fuels. The burner assembly comprises a burner section, exhaust section, radiant tube, plenum and a jet pump assembly. A volume of exhaust gas drawn from the stream of exhaust gases into the jet pump assembly by way of a motive gas is flowed into a stream of combustion air so as to vitiate the oxygen content of the combustion mixture. When the combustion mixture is combusted with fuel in the burner section, the production of nitrous oxides and other harmful emission is mitigated.

Abstract: A combination burner which uses primary and secondary fuel injection and improves liquid propane combustion. The burner supplies primary air, while secondary air is swirled to shape and mix the flame when the burner is firing "on oil". When the burner is firing "on gas", primary air enters the burner through an annulus at the atomizing air pipe or conduit so as to have the primary gas enter that pipe; secondary gas is injected radially into the air stream at a downstream location relative to an atomizing nozzle. In using liquid propane (butane) to fire the burner, two stage fuel injection is used, with a stream of fuel being injected upstream and toward the burner centerline and another stream of fuel being injected downstream and outwardly away from the burner centerline.

Abstract: A burning method provides a versatile burner by promoting rapid mixing and a stable flame to reduce NO.sub.x and CO emissions over a wide operating range. The burner includes a primary fuel supply, a combustion air supply arranged to supply combustion air at low pressure, and a swirler for swirling the combustion air. When the primary fuel supply is gaseous fuel, the gaseous fuel is introduced axially into the swirling combustion air. Secondary gas nozzles are arranged at the exit of the burner to supply and mix boost gas for combustion with the combustion air when the gaseous fuel is the primary fuel supply. An atomizer is arranged for atomizing liquid fuel when the primary fuel supply is a liquid fuel.

Abstract: A burner and burner firing method and system for a furnace combustion chamber in which a burner, having an ignition chamber for discharging an ignited combustible mixture of primary air and fuel into the furnace combustion chamber, and a plurality of nozzle ports for directing a high velocity stream of secondary air into the furnace combustion chamber in a direction generally parallel to the direction of flow from said ignition chamber, is operated in a first mode at furnace combustion chamber temperatures up to a transitional temperature by accelerating a burning mixture of fuel and air to moderately high velocities into the furnace combustion chamber, and in a second mode at furnace combustion temperatures above said transitional temperature by introducing a relatively low velocity stream of fuel mixed with a minor amount of air needed for stoichiometric combustion and accelerating a separate stream of air to high velocities into the furnace combustion chamber for mixture with said low velocity stream downs

Abstract: A burning method promotes rapid mixing and a stable flame in a burner to reduce NO.sub.x and CO emissions and to provide a smoother, quieter operation. The burner includes a primary fuel supply, a combustion air supply arranged to supply combustion air at low pressure, and a swirler for swirling the combustion air. When the primary fuel supply is gaseous fuel, the gaseous fuel is introduced radially into the swirling combustion air. A bluff body cone is arranged near the exit of the burner so as to be encountered by at least the swirling combustion air. An atomizer is arranged within the bluff body cone for atomizing liquid fuel when the primary fuel supply is a liquid fuel. Boost gas nozzles are arranged toroidily at the exit of the burner to supply and mix swirling boost gas for combustion with the combustion air when the gaseous fuel is the primary fuel supply, and mixer tabs are disposed around the periphery of the exit.

Abstract: The burner is capable of operating either on gas or fuel oil and includes a burner block with a high velocity discharge nozzle. Combustion air for the burner is rotationally spun to promote more complete combustion of the fuel and to reduce the formation of carbon deposits along the block and within the discharge nozzle. As a result of the spinning combustion air, a high rotational velocity is imparted to the flame so that the flame threads corkscrew-fashion out of the discharge nozzle and is formed with a hollow center.