Disclosed is a gas furnace including a mixer configured to mix air and fuel gas introduced from an intake pipe and a manifold respectively so as to produce an air-fuel mixture, a mixing pipe configured to allow the air-fuel mixture having passed through the mixer to flow therein, a burner assembly configured to combust the air-fuel mixture having passed through the mixing pipe so as to generate combustion gas, heat exchangers configured to allow the combustion gas to flow therein, an exhaust pipe configured to discharge exhaust gas, which is the combustion gas having passed through the heat exchangers, to the outside. The gas furnace further includes a recirculator installed around the exhaust pipe and configured to guide a portion of the exhaust gas flowing in the exhaust pipe to the mixer, and may thus greatly reduce or fundamentally block NOx emissions.

A fuel nozzle assembly includes an inner fuel nozzle; a plurality of outer fuel nozzles disposed radially around the inner fuel nozzle, each outer fuel nozzle including a central body for fuel injection, a shroud spaced apart from and surrounding the central body, the shrouds forming an outer periphery of the fuel nozzle assembly, and an inlet formed at one end of the shroud; and a peripheral rim formed at the inlets and disposed to cover at least a portion of the outer periphery. The fuel nozzle assembly is connected to an end plate of a combustion chamber. The one end of a corresponding shroud is disposed at a set distance from an end plate of a combustion chamber, the set distance depending on at least one of relative positions of the inner fuel nozzle and the plurality of outer fuel nozzles and an inlet radius of the corresponding shroud.

A premixing device includes a first and a second venturi in which air flows by rotation of a centrifugal fan, first and second communication openings disposed in the venturis, respectively, for allowing fuel gas supplied from a gas supply passage to flow out, a flap valve capable of opening and closing the second venturi on a side downstream of the second communication opening, and an equalizing valve disposed in the gas supply passage on a side upstream of the first and the second communication openings. The gas supply passage, which connects between an outlet of the equalizing valve and the first and the second communication openings, diverges from the outlet of the equalizing valve to independently form a first gas passage and a first straight path, and a second gas passage and a second straight path for the venturis, respectively.

A multi-cavity gas-air mixing device includes at least two mixing cavities each having an air inlet and a mixture outlet communicated with a combustor, wherein each of the mixing cavities has a built-in gas pipeline, each of the gas pipelines is provided with a gas jet, and the orientation of the gas jet is intersected with a flow direction of air entering into the mixing cavities. The device effectively segments the gas-air mixer and achieves a large load regulation ratio, without producing condensate water at any load segment, thereby improving the system reliability and service life. The built-in gas pipeline not only actively controls the fuel in the open-close control pipeline, but also reduces the volume of the mixer and largely decreases the cost.

Improvements for a gas burner bar are provided utilizing reduced parts, easier assembly, and greater reliability. In one or more implementations a portion of an air shutter is disposed between two parts of an injector assembly: an injector and an injector fitting. Assembly in this manner results in proper alignment of the injector assembly thus negating problems that arise with misalignment.

A burner assembly including a gas inlet fixture for use with a burner tube, the gas inlet fixture including a plurality of tabs to engage a neck of a gas control valve to improve ignition and center the gas flow down the center of the burner tube.

A premix burner made up of an air inlet tube of length L and a single specific gas injection, the gas injection includes an upstream gas injector, a mixer, a downstream gas injection situated at a distance L3 from an upstream end of the air inlet tube and a stabilizing element, where the gas injection constitutes a one-piece mechanical assembly that ensures a self-stable elementary flame.

A burner device for supplying a mixture of a fuel gas and a combustion-supporting gas into a combustion region includes: a mixing path configured to inject the mixture from a downstream end portion of the mixing path into the combustion region; a fuel gas injection nozzle configured to inject the fuel gas into the mixing path toward the combustion region; and a combustion-supporting gas supply swirler configured to inject the combustion-supporting gas such that at least a part of the combustion-supporting gas collides directly with the fuel gas injected from the fuel gas injection nozzle, in a direction of a tangent line that is tangent to a fuel injection hole of the fuel gas injection nozzle on a cross-section.

A cooktop appliance includes a top panel that defines an opening. A first gas burner is positioned on the top panel at the opening of the top panel. A second gas burner includes a burner body, a horizontal mixing tube and a fuel orifice. The burner body is positioned on the top panel away from the opening of the top panel. The horizontal mixing tube is positioned below the top panel and extends between the burner body and the fuel orifice. The fuel orifice is positioned below the top panel at the opening of the top panel.

A horizontally-fired burner system includes, in a combustion volume, a distal flame holder, the distal flame holder including a plurality of columns each formed from a respective plurality of refractory tiles, and a fuel and combustion air source configured to output a flammable fuel and air mixture toward the distal flame holder. The distal flame holder is configured to hold a combustion reaction adjacent to each of the plurality of columns.