Abstract: A lean premix burner has a center fire nozzle, which includes radial gas outlets and a ring of outlets. The gas outlets from the center fire nozzle are fed from a manifold. The center fire gas is controlled separately from the main gas supply, which has several advantages, including enhanced turn down capability.

Abstract: A low NOx burner system is disclosed that reduces the emission of CO and HC during cold furnace startups, minimizes NOx formation with preheated air, and provides a flat stable flame due to burner design improvements including three stage combustion. The burner system is designed to operate in either a low or high temperature mode by controlling the amount of combustion air provided to stage 1 and stage 2 combustion. The burner system is designed to heat the interior of a furnace for high-temperature combustion/furnace processes, such as aluminum melting and steel processes. The burner system can also be used for low temperature processes at temperatures below the auto-ignition temperature of the fuel and still produce very low CO, HC and NOx emissions.

Abstract: A burner assembly for lean, low NOx combustion may include a gaseous fuel manifold, counter-swirl vanes, and a converging nozzle with bluff body flame anchors. A cooling air tube optionally extends from the air inlet to the nozzle.

Abstract: The present invention is a method for achieving low NOx single-stage combustion. A high velocity burner is run normally, with combustion occurring within both the burner combustion chamber and furnace chamber, until the gases within the furnace exceed the auto-ignition temperature of the gaseous fuel. The gaseous fuel is then shut off until the temperature within the burner combustion chamber drops below the auto-ignition temperature of the gaseous fuel. The gaseous fuel is then turned back on and the gaseous fuel auto ignites within the furnace chamber. The combustion then occurs only within the furnace chamber and not in the burner combustion chamber.

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: The present invention is an air-staged low NOx burner for firing a gaseous fuel. The burner fires three stages, with the first stage of combustion taking place substantially within a burner cup section of a refractory baffle, the second stage of combustion taking place adjacent to the baffle and downstream of the baffle, and the third stage of combustion within a furnace. The flow of main combustion air adjacent to the baffle creates a negative pressure zone adjacent to the baffle. The present invention is also a method for low NOx staged combustion.

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: As electronic programmable valve positioning linkage for a burner used in a hot mix asphalt plant is associated with fuel, air and optionally flue gas recirculation valve motors. To avoid an undesired rich condition which might result in an explosive condition, the linkage employs a program logic which changes a valve position, depending on increase or decrease of the burner output, in response to a temperature controller and thereby maintain an acceptable lean condition. The air valve motor is controlled by the temperature controller when burner output is to be increased with the fuel valve motor following the air valve motor, and the fuel valve motor is controlled when the burner output is to be decreased with the air valve motor following the fuel valve motor. In conjunction with the linkage, a mass flow system can be provided to calculate fuel/air and/or flue gas recirculation ratios based upon measurement of air flow, fuel flow and flue gas flow.

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: A draft control for material processing apparatus, such as asphalt plants, having a chamber through which material to be processed is passed for contact with combustion gases and heat originating in a fuel supplied burner which may require a draft to draw air into the chamber for complete combustion of burner supplied fuel and to exhaust the products of combustion and other gaseous materials from the chamber. The air pollutants and the percent oxygen in the exhausted gases are monitored, and the draft is adjusted between minimum and maximum values for a given burner set point when the air pollutant content of the stack gases exceeds a predetermined maximum limit. The direction of draft adjustment is determined by the percent oxygen in the exhaust gases.

Abstract: A swirl-type internal flame recirculation burner as used to fire asphalt plant aggregate dryers, air heaters and calcining kilns and method includes an atomizer assembly for swirling primary air in two concentric streams with the inner stream swirling more rapidly than the outer stream. Fuel oil is blast atomized in a continuous sheet into the inner stream without prefilming and then is shear atomized as the inner and outer streams violently intermix. The burning and swirling fuel and primary air mixture recirculates upstream along the burner axis. Secondary air is swirled in the same direction as the primary air and surrounds the primary air stream to promote further mixing and internal recirculation. A metal frustro-conical flame holder surrounds the burner head to stabilize and shape the recirculation flame and shield low-burn flames from tertiary air. The swirl of the secondary air is also adjusted to shape the flame. The burner may also be fired on gas or a combination of gas and oil.

Abstract: An industrial burner having an axial recirculation flame with active vortex mixing in the combustion chamber and method.

Abstract: A multi-fuel industrial heating burner having an exhaust velocity of about 15,000 feet per minute. The fuel is first burned in a swirling toroidal recirculation zone and flows into the burner tile and shear mixes with a counter-swirling flow of combustion air flowing along the burner tile. As the flows shear mix, additional combustion air is provided to the central burning gases and the rotational momentum of the swirling flows is dissipated. The burner discharge gases flow axially without swirl.

Abstract: An oil burner atomizer and method for light and heavy fuel oils where the oil is spread circumferentially of a number of oil delivery bores and two heavy oil flows are formed for each delivery bore. The oil flows are atomized in low-pressure primary air. The atomizer includes an annular low-pressure oil ligament formation zone upstream of the initial atomizing air flow.

Abstract: A combination oil and gas fired burner includes a body, an air nozzle and an end plate. The end plate is mounted on the upstream end of the body and holds the air nozzle in place within the body. An atomizing assembly carried by the end plate is fitted within an aperture in the air nozzle adjacent the combustion chamber. The burner is readily disassembled by removing the end plate, atomizing assembly and the air nozzle from the body without requiring complete disassembly and removal of the body from its mounting plate. On the reassembly, fuel and air flow openings in the burner are returned to their original angular orientation so that there is no need to readjust the fuel delivery system.