Provided is a water heater including a burner that receives a supply of combustion air from a fan, a heat exchanger having a heat transfer tube, and a combustion chamber case in which a combustion chamber of the burner is formed in the interior thereof and which is to be capable of guiding combustion gas generated by the burner to the heat exchanger. The water heater further includes a unit case that surrounds the combustion chamber case, and a region on the outside of the combustion chamber case within the unit case serves as an air pressure chamber having a higher pressure than the combustion chamber. Thus, combustion gas leakage to the outside can be prevented or suppressed appropriately by means of a simple configuration.

A burner assembly having a blower housing, a blower to supply air to the burner assembly, a blast tube having a longitudinal axis, a fuel source to supply fuel to the burner assembly, a center tube that is substantially parallel to the longitudinal axis and conveys air and fuel to a center tube burner end opening, a plurality of premix tubes, each of which is substantially parallel to the longitudinal axis and conveys air and fuel to a premix tube burner end opening, a diffuser that is disposed in the center tube near the center tube burner end opening, a nozzle that is disposed in the center tube substantially perpendicular to the diffuser. The center tube air and fuel mixture is fuel rich and the premix tubes air and fuel mixture is fuel lean. A method for burning the center tube air and fuel mixture and the premix tubes mixtures.

A fuel supply system for an aircraft engine, comprises a gaseous fuel source and a fuel nozzle. The fuel nozzle includes a housing having a housing interior chamber and a fuel swirler disposed inside the housing interior chamber. The fuel swirler is fluidly connected to the gaseous fuel source for directing gaseous fuel to a combustor of the aircraft engine. The fuel swirler defines a gaseous fuel path extending from a fuel inlet to a fuel outlet. The gaseous fuel path includes a plurality of discrete apertures distributed around a circumference of the fuel swirler, each of the plurality of discrete apertures having a cross-sectional area selected to prevent a flame from propagating in an upstream direction through the gaseous fuel path towards the gaseous fuel source.

A fuel nozzle includes a shroud; an injection cylinder surrounded by the shroud and configured to supply fuel to a combustion chamber; a swirler disposed between the injection cylinder and the shroud; and a porous disk disposed downstream of the swirler to surround an outer peripheral surface of the injection cylinder in order to prevent a flashback phenomenon occurring due to a reduction in pressure around the swirler. The porous disk includes a disk body to block a flame produced in the combustion chamber, and a plurality of flow holes are formed in the disk body through which the fuel flows. It is possible to prevent flashback by installing the porous disk downstream of the swirler, and to impart linearity and a swirling effect to the fuel passing through the fuel nozzle by forming variously configured flow holes in the porous disk.

Horizontal immersion tube boilers include a plurality of burner nozzles positioned in substantial alignment with a respective plurality of boiler tubes. Fuel-air mixture directed through the burner nozzles are ignited by a pilot flame system positioned proximate to the burner nozzles within a combustion chamber. The burner nozzles and pilot flame system receive air from a secondary air manifold having inlets that provide secondary air into the combustion chamber. The flames extending from the burner nozzles are directed into the respective boiler tubes, which exchange heat from the flame into water within a boiler shell. The secondary air inlets direct air around the burner nozzles and toward the boiler tubes, creating an air blanket around each burner nozzle for reducing turbulence and guide the flames into their respective boiler tubes. An improved flame arrestor within the nozzle prevents flame back-flow when modulating to lower firing rates.

A rich-lean combustion apparatus includes a first plate and a second plate provided to face each other to allow a rich mixture to flow therebetween through a rich mixture passage, a third plate provided to allow a lean mixture to flow through a lean mixture passage formed between the second plate and the third plate, a first burner port member for combusting the rich mixture, and a second burner port member for combusting the lean mixture, wherein, between the first plate and the second plate, a mixture inlet into which some of air supplied from a ventilator and a fuel gas injected from a nozzle are introduced, a mixture passage introduction portion and a mixture passage diffuser for allowing the rich mixture flowed into through the mixture inlet to flow to the rich mixture passage, an air inlet into which the remaining of the air supplied from the ventilator is introduced, and an air passage introduction portion through which the air flowed into through the air inlet flows are formed, and wherein a plurality of air through-holes are formed to pass through the second plate to allow the air of the air passage introduction portion to be spouted into an air passage formed between the second plate and the third plate, and a plurality of distribution holes are formed to pass through the second plate to allow some of a mixture passing the mixture passage diffuser to be spouted into the lean mixture passage.

A gas heater includes a premix burner, a supply channel for supplying a mixture of a gaseous fuel and air to the burner, and a check valve placed in the supply channel upstream of the burner. The check valve includes a moveable valve body having a first end position in which the check valve is opened and a second end position in which the check valve is closed. In a first pressure condition in which a pressure upstream is higher than a pressure downstream, the valve body is urged to the first end position. In a second pressure condition in which the pressure upstream is lower than the pressure downstream the valve body is urged to the second end position. After closure of the check valve the check valve remains closed for a delay time.

A fuel nozzle includes a shroud; an injection cylinder surrounded by the shroud and configured to supply fuel to a combustion chamber; a swirler disposed between the injection cylinder and the shroud; and a porous disk disposed downstream of the swirler to surround an outer peripheral surface of the injection cylinder in order to prevent a flashback phenomenon occurring due to a reduction in pressure around the swirler. The porous disk includes a disk body to block a flame produced in the combustion chamber, and a plurality of flow holes are formed in the disk body through which the fuel flows. It is possible to prevent flashback by installing the porous disk downstream of the swirler, and to impart linearity and a swirling effect to the fuel passing through the fuel nozzle by forming variously configured flow holes in the porous disk.

To provide a gas turbine combustor that can suppress a generation amount of NOx and maintain a flame holding property, while suppressing burn damage around a pilot nozzle including the pilot nozzle. A gas turbine combustor includes a pilot nozzle that can inject fuel F and cooling air A for cooling a nozzle tip, a flow regulating valve that can adjust a flow rate of cooling air to be supplied to the pilot nozzle, a detection sensor that detects a combustion state of fuel, and a control device that controls the flow regulating valve based on a detection result of the detection sensor.

A furnace includes a gas burner exposed to a heat-exchange tube. An inducer is fluidly coupled to the heat-exchange tube and configured to induce draft air through the heat-exchange tube. A regulator is fluidly coupled to the gas burner. A rollout shield is disposed adjacent to the gas burner. A rollout switch is disposed in the rollout shield. The rollout switch is electrically coupled to the regulator. At least one vent is formed through the rollout shield adjacent to the rollout switch. The vent provides a path for a rollout flame to the rollout switch. The at least one vent is disposed on at least two sides of the rollout switch.