The present invention relates to a combustion apparatus capable of reducing the emission amount of nitrogen oxide and enabling stable combustion in the entire area of a set load. The combustion apparatus includes: a premixing chamber for premixing air and a gas; a blower for supplying a mixed-gas of the air and the gas to a burner; a combustion chamber for burning the mixed-gas by ignition of the burner; a heat exchanger for exchanging heat with water by using combustion heat in the combustion chamber; and an exhaust gas discharge part for discharging the exhaust gas passing through the heat exchanger, wherein the premixing chamber is formed in a Venturi shape having a throat part of which the cross-section area is tapered between an inlet and an outlet through which the air passes, the throat part of the premixing chamber being connected to a gas supply part for supplying a gas for combustion, and to an exhaust gas recirculation tube to which some of the exhaust gas having passed through the heat exchanger is introduced in proportion to differential pressure according to the flow rate of the mixed-gas passing through the throat part.

A venturi nozzle for a gas combustor includes an orificed gas nozzle, a venturi tube and one or more support members. The orificed gas nozzle has a longitudinal axis, an inlet and an outlet. The venturi tube is aligned with the longitudinal axis and has an entrance proximate to the outlet of the orificed gas nozzle and an exit. The support member(s) are attached between the orificed gas nozzle and the venturi tube to create a gap between the venturi tube and the orificed gas nozzle. In some embodiments, two or more venturi nozzles can be combined together in various configurations into a nozzle assembly or multi-nozzle gas combustor and attached, mounted or disposed within a stack, chimney or vented enclosure. The wall(s) of the stack, chimney or vented enclosure may include one or more openings, cut outs or vents to provide primary and secondary air to the venturi nozzles.

A burner device (190) comprising an air intake, a burner head (192) including an ignition device, a body section (196) defining a fluid flow channel between said air intake and said burner head (192), and a gas injector (205) for injecting combustible gas into said fluid flow channel. The burner head (192) is oriented such that its longitudinal axis is substantially perpendicular to the plane in which the channel is defined and in which fluid flows, in use, along said channel.

The hydrogen gas burner has a first pipe extendable into an oven chamber, having a plurality of through-holes in a sidewall thereof, fluidly communicating an interior of the first pipe with an exterior thereof. A combination gas valve and pressure regulator is connected to an inlet of the first pipe and fluidly connects a hydrogen gas source with the first pipe, such that the hydrogen gas flows into the first pipe and exits therefrom through the through-holes. An igniter ignites and initiates combustion of the exiting hydrogen gas. A second pipe is extendable into the oven chamber, having apertures in the sidewall thereof fluidly communicating an interior of the second pipe with an exterior thereof. The second pipe fluidly connects at an inlet thereof with an air source, whereby the air flows into the second pipe from the inlet thereof and exits out of the second pipe through the apertures.

A premixing apparatus has a butterfly valve provided in an air supply passage, a zero governor and a variable throttle valve interposed in a gas supply passage. A control is performed to switch a combustion capacity between at least two stages of a large-capacity stage and a small-capacity stage through change in opening degrees of the butterfly valve and the variable throttle valve. At the small-capacity time, in case the opening degree of the variable throttle valve, when regulated so that the λ becomes a predetermined value, has been changed more to the small-opening-degree side than the predetermined small-capacity opening degree, in a state in which the opening degree of the variable throttle valve has been returned to the predetermined small-capacity opening degree, the opening degree of the butterfly valve is regulated such that the λ becomes the predetermined value, and the small-capacity opening degree of the butterfly valve is renewed to the predetermined value when the λ becomes the predetermined value.

Process and apparatuses for providing a stable flame in a burner assembly are provided. In an embodiment, the apparatus includes a burner assembly comprising a burner tile having a top surface, an outside surface, a pre-mix region and defining an interior space for introduction of combustion air. A plurality of primary fuel tips are disposed in the interior space for injection of a primary fuel followed by mixing of a portion of the primary fuel and a portion of the combustion air mix in the pre-mix region to provide a primary fuel-air mixture. A plurality of secondary fuel tips are located on the top surface or mounted near the outside surface of the burner tile. A plurality of low velocity ports are located on the top surface of the burner tile for injecting the primary fuel-air mixture from the pre-mix region.

A premixing apparatus includes a mixing unit, an air supply adjusting unit, and a gas switching unit. The mixing unit draws a fuel gas in the mixing unit by supplied air to mix the fuel gas and the supplied air with each other. The air supply adjusting unit applies a load on the supplied air flowing toward the mixing unit and switches the load. The gas switching unit switches a gas amount of the fuel gas to be supplied to the mixing unit.

The hydrogen gas burner has a first pipe extendable into an oven chamber, having a plurality of through-holes in a sidewall thereof, fluidly communicating an interior of the first pipe with an exterior thereof. A combination gas valve and pressure regulator is connected to an inlet of the first pipe and fluidly connects a hydrogen gas source with the first pipe, such that the hydrogen gas flows into the first pipe and exits therefrom through the through-holes. An igniter ignites and initiates combustion of the exiting hydrogen gas. A second pipe is extendable into the oven chamber, having apertures in the sidewall thereof fluidly communicating an interior of the second pipe with an exterior thereof. The second pipe fluidly connects at an inlet thereof with an air source, whereby the air flows into the second pipe from the inlet thereof and exits out of the second pipe through the apertures.

The disclosed technology includes a water heater system having a blower, an igniter, a burner, a heat exchanger, and a refractory configured to attach to the burner and the heat exchanger. The refractory can include a unitary ceramic housing having a top and a plurality of sidewalls and be configured to retain heat from combustion gases. The top can have a burner aperture configured to receive at least a portion of the burner and the plurality of sidewalls can form a cavity configured to receive at least a portion of the heat exchanger. One or more of the sidewalls can additionally have a protrusion extending laterally along an inside surface of the sidewall that is configured to contact the heat exchanger to form a seal between the heat exchanger and the refractory. A sealing material can substantially create a seal between the refractory and the heat exchanger.

A premixing device includes: a gas flow passage forming member in which an x direction is used as an axial length direction, and a Venturi-shaped gas flow passage into which air can flow in from the outside is formed inside; and a blade portion positioned in the gas flow passage, extending in a y direction, and equipped with a fuel gas outlet. The blade portion includes first and second blade portions spaced apart from each other in a z direction, and an air flow path near the center through which a part of the air flows is formed between these first and second blade portions. At least one of a pair of surfaces of the first and second blade portions facing each other is equipped with an inner bulging portion that bulges in the z direction so as to squeeze a part of the air flow path near the center.