High turndown ratio gaseous fuel burner nozzles and the control thereof are provided. High turndown ratio gaseous fuel burner nozzles include a mechanically adjustable nozzle port, such as in the form of an iris port, for expanded turndown control. A nozzle extension longitudinally extending from the mechanical adjustable nozzle port can be included to assist in shaping the flow of combustible gas from the nozzle port. A laminar flow insert can be housed within the nozzle extension to assist in producing laminar flow of the combustible gas flowing therethrough. A burner nozzle controller in control communication with the mechanically adjustable nozzle port can adjust the size of the nozzle port to selectively maintain exit velocity of the gaseous fuel from the nozzle port for one or more of combustion stability and flame stability.

High turndown ratio gaseous fuel burner nozzles and the control thereof are provided. High turndown ratio gaseous fuel burner nozzles include a mechanically adjustable nozzle port, such as in the form of an iris port, for expanded turndown control. A nozzle extension longitudinally extending from the mechanical adjustable nozzle port can be included to assist in shaping the flow of combustible gas from the nozzle port. A laminar flow insert can be housed within the nozzle extension to assist in producing laminar flow of the combustible gas flowing therethrough. A burner nozzle controller in control communication with the mechanically adjustable nozzle port can adjust the size of the nozzle port to selectively maintain exit velocity of the gaseous fuel from the nozzle port for one or more of combustion stability and flame stability.

A burner apparatus and method which provide an increased amount of internal flue recirculation for reducing NO.sub.x emissions by ejecting a series of surrounding primary fuel streams and also ejecting on one or more subsequent series of surrounding fuel streams outside of the burner wall toward the burner combustion wherein each succeeding series of surrounding fuel streams must travel a greater distance to the combustion zone and each series of surrounding fuel streams must contact one or more radial impact structures provided on the exterior of the burner wall.

A burner apparatus and method which provide an increased amount of internal flue recirculation for reducing NO.sub.x emissions by ejecting a series of surrounding primary fuel streams and also ejecting on one or more subsequent series of surrounding fuel streams outside of the burner wall toward the burner combustion wherein each succeeding series of surrounding fuel streams must travel a greater distance to the combustion zone and each series of surrounding fuel streams must contact one or more radial impact structures provided on the exterior of the burner wall.

Disclosed are an anti-backflow premixing device and a fuel gas water heater, where the anti-backflow premixing device includes a casing body, a premixing cavity is provided in the casing body, and the premixing cavity includes a gas outlet pathway; a baffle, the baffle is connected in the casing body, the baffle has a first position and a second position, the baffle can continuously move between the first position and the second position, the baffle obstructs the gas outlet pathway of the premixing cavity when at the first position, and the gas outlet pathway gradually opens when the baffle is moved from the first position to the second position; and a fuel gas passage, the fuel gas passage and the premixing cavity being in communication.

A cylindrical burner apparatus and method which produce low NO.sub.x emissions and low noise levels without being dependent upon a blower, or natural draft, for providing air flow or flue gas recirculation. A flow of combustion air is induced into an initial tube pass of the burner by discharging a gas fuel from a plurality of discharge ports located in the initial tube pass. At the same time, a flow of recycled flue gas is induced through a bypass duct between a subsequent tube pass of the burner and the initial tube pass by discharging one or more jets of gas fuel through the bypass duct.

A cylindrical burner apparatus and method which produce low NO.sub.x emissions and low noise levels without being dependent upon a blower, or natural draft, for providing air flow or flue gas recirculation. A flow of combustion air is induced into an initial tube pass of the burner by discharging a gas fuel from a plurality of discharge ports located in the initial tube pass. At the same time, a flow of recycled flue gas is induced through a bypass duct between a subsequent tube pass of the burner and the initial tube pass by discharging one or more jets of gas fuel through the bypass duct.

To further reduce the NOx emission, the invention provides a mixing device (10) for a burner (16) having reduced NOx production, comprising a centrally arranged first mixing unit (18) for producing a first fuel-air mixture for a primary flame zone (120), wherein the first mixing unit (18) has at least one first fuel nozzle (38) and a baffle plate (40), a second mixing unit (20) for producing a second fuel-air mixture for a secondary flame zone (122), which encloses the primary flame zone (120), wherein the second mixing unit (20) has multiple second fuel nozzles (70), characterized by a sealing air producing unit (24) for producing a sealing air flow in a sealing air zone, which encloses the primary flame zone (120) of the first mixing unit (18) arranged downstream of the baffle plate (40), wherein the second mixing unit (20) is designed to deliver the second fuel-air mixture into the secondary flame zone (122), which encloses the sealing air zone (126), and wherein the second mixing unit (20) is arranged around the sealing air producing unit (24), and by a third mixing unit (22) which is arranged radially between the sealing air producing unit (24) and the second mixing unit (20) and has a swirl generator (76) and at least one third fuel nozzle (74), which is arranged upstream of the swirl generator (76) in a premixing zone (78), through which a swirled air flow flows to the swirl generator (76), to premix fuel from the third fuel nozzle (74) with the swirled air flow before the swirl generation.

To further reduce the NOx emission, the invention provides a mixing device (10) for a burner (16) having reduced NOx production, comprising a centrally arranged first mixing unit (18) for producing a first fuel-air mixture for a primary flame zone (120), wherein the first mixing unit (18) has at least one first fuel nozzle (38) and a baffle plate (40), a second mixing unit (20) for producing a second fuel-air mixture for a secondary flame zone (122), which encloses the primary flame zone (120), wherein the second mixing unit (20) has multiple second fuel nozzles (70), characterized by a sealing air producing unit (24) for producing a sealing air flow in a sealing air zone, which encloses the primary flame zone (120) of the first mixing unit (18) arranged downstream of the baffle plate (40), wherein the second mixing unit (20) is designed to deliver the second fuel-air mixture into the secondary flame zone (122), which encloses the sealing air zone (126), and wherein the second mixing unit (20) is arranged around the sealing air producing unit (24), and by a third mixing unit (22) which is arranged radially between the sealing air producing unit (24) and the second mixing unit (20) and has a swirl generator (76) and at least one third fuel nozzle (74), which is arranged upstream of the swirl generator (76) in a premixing zone (78), through which a swirled air flow flows to the swirl generator (76), to premix fuel from the third fuel nozzle (74) with the swirled air flow before the swirl generation.

A thermal lance for unplugging a vessel discharge port. The thermal lance including an elongated cylindrical hollow tube made from a combustible material, the tube having an axial length with first and second ends. The tube having a cylindrical sidewall defined by an outer wall having an outer diameter and an inner wall having an inner diameter, with a wall thickness between the outer and inner walls. The tube having a longitudinal axis. At least one projection is formed integrally on the first end and has a length extending away from the first end in substantially the same direction as the longitudinal axis. A telescoping thermal lance assembly is also disclosing that includes a housing and an extension tube within which the lance is located.