A premixing apparatus has: a butterfly valve and a changeover valve for changing over, between high and low, a ventilation resistance in an air supply passage and in a gas supply passage, respectively; and an interlocking mechanism to open or close the changeover valve in interlocking with the opening or closing of the butterfly valve. In either of the small-capacity state in which the ventilation resistance in the air supply passage and in the gas supply passage is made high to attain a small-capacity state or in a large-capacity state to attain a large-capacity state, adjustments are arranged to be made to make appropriate the excess air ratio of the air-fuel mixture. An interlocking mechanism is constituted: to maintain the changeover valve in a fully-closed state when the butterfly valve lies in a predetermined first rotation angle range inclusive of the closed posture; and to maintain the changeover valve in a fully-opened state when the butterfly valve lies in a predetermined second rotation angle range inclusive of the opened posture. The rotation angle of the butterfly valve at which the excess air ratio of the air-fuel mixture becomes the predetermined appropriate value within the first rotation angle range is set to a closing-side stop angle of the butterfly valve. The rotation angle of the butterfly valve at which the excess air ratio of the air-fuel mixture becomes the predetermined appropriate value within the second rotation angle range is set to an opening-side stop angle of the butterfly valve.

A premixing apparatus in which a downstream end of a gas supply passage having interposed therein a flow control valve is connected to a gas suction section disposed in an air supply passage on an upstream side of a fan. The premixing apparatus has: a butterfly valve as an air resistance changeover device for changing over, between high and low, a ventilation resistance in that section of the air supply passage which is on the upstream side of the gas suction section; and a gas resistance changeover device for changing over, between high and low, a ventilation resistance in that section of the gas supply passage which is on the downstream side of the flow control valve. Wind noises at the time of closing the butterfly valve can be prevented. For that purpose, in that section of the air supply passage which is on the upstream side of the gas suction section, an inner tube containing therein the butterfly valve is disposed while leaving a clearance to an inner circumferential wall surface of the air supply passage. A subsidiary passage which is parallel with a main passage inside the inner tube is constituted by the clearance between the inner circumferential wall surface of the air supply passage and an outer peripheral surface of the inner tube.

A turn down ratio (TDR) damper which controls an amount of gas and air flowing in the TDR damper and deliver the controlled gas and air to a turbo fan is disclosed. The TDR damper includes: air passages comprising a first air passage and a second air passage, the first air passage and the second air passage separately formed so that the air move through each path; gas passages comprising a first gas passage and a second gas passage, the first gas passage and the second gas passage separately formed so that the gas move through each path; and opening and closing means for opening and closing the second air passage and the second gas passage at the same time. The air passages and the gas passages may be separately formed and reached outlets connected to the turbo fan so that the air and gas may be delivered to the turbo fan through a separate path.

The present disclosure discloses a gas mixing device and a gas water heating device. In which, a gas mixing device, comprises: a shell provided with a fuel gas channel for inputting fuel gas, an air channel for inputting air and a gas mixing channel, the fuel gas channel being provided with a first cut-off portion capable of changing a flow area, and the air channel being provided with a second cut-off portion capable of changing a flow area; a moving part movable in the shell, the moving part simultaneously changing the flow areas of the first cut-off portion and the second cut-off portions by moving. The gas mixing device and the gas water heating device can provide a higher regulation ratio, thereby solving the problem that the water temperature is too high in summer.

A burner includes a porous support and a combustion tube along which is mounted the porous support. The combustion tube has one or more openings configured to pass fuel to the porous support. The combustion tube is formed by a plurality of tubular modules assembled together. The burner includes at least one distribution tube extending inside the combustion tube and configured to distribute fuel in a predetermined manner in the combustion tube.

A burner apparatus and method of operating the burner apparatus include a burner housing, and a group of fuel and air swirlers maintained by the burner housing, with the group of fuel and air swirlers supplied by a common fuel and air source. The fuel and air can be directed to one or more of the fuel and air swirlers at a time. Each fuel and air swirler among the group of fuel and air swirlers can mix the fuel and the air, resulting in a combustible mixture of the fuel and the air downstream of the group of fuel and air swirlers. The burner apparatus be implemented as a low NOx multi-port burner apparatus.

The present disclosure deals with the regulation of fluid flows in the presence of turbulence. The teachings thereof may be embodied in regulating a fluid in a combustion device. For example, a method for regulating a burner device may include: requesting a flow of a fluid through a feed duct; assigning the requested flow to a setting of a first actuator; transmitting a first signal to set the first actuator; generating a mass flow signal representing an actual flow through the side duct; correlating the second signal to an actual value of the flow through the side duct; correlating the requested flow through the feed duct to a required flow through the side duct; generating a regulation signal with the regulator for the second actuator as a function of the actual value of the flow through the side duct and the requested value of the flow through the side duct; and transmitting the generated regulation signal to the second actuator.

A fuel-operated vehicle heater includes a burner area (12) with a combustion chamber (14); a fuel pump (24); and a combustion air blower (28). A pressure sensor (38) detects a feed back pressure. An actuating unit (36) actuates the fuel pump (24) with a predefined value of a pump operating variable, and actuates the combustion air blower with a predefined value of a blower operating variable. A heater process includes detecting the feed back pressure in case of a feed operating state set during the combustion operation and comparing the detected feed back pressure (P.sub.e) with an expected feed back pressure (P.sub.E) for the set feed operating state. If the detected feed back pressure deviates from the expected feed back pressure the pump operating variable is changed such that the feed back pressure changes toward the expected feed pressure and/or essentially corresponds to the expected feed back pressure.

A high turn down ratio flare tip assembly, that allows for both low and high flowrate and pressure flows using a single flare. The flare assembly comprising a nozzle tube connected to the waste stream fuel inlet at one end. The other end of the flare tip assembly providing a seat for a conical structure with flow through orifices/ports that allow the waste stream to flow therethrough during low pressure operation. The conical structure connected to one end of a connecting rod, the connecting rod extending longitudinally downward through the nozzle tube and connected to a spring assembly. The flare tip assembly is designed to allow low flow and pressure to pass through the cone orifices, and during high flow and pressure operation, the cone is unseated from the nozzle tube, allowing the waste stream to flow therethrough. The flare tip assembly also includes a slotted/holed shroud that allows for smokeless combustion of the waste stream during high flow and pressure conditions.

A gas-mixing device includes: a shell, where the shell is provided with an air channel for conveying air, a fuel gas channel for conveying fuel gas, and a mixing-gas channel connecting downstream of the air channel and the fuel gas channel. The fuel gas channel includes a first sectional flow area and the air channel includes a second section flow area; which are located on the movable part of the shell. The movable part is provided with a flexible separation component which hermetically separates the air channel and the fuel gas channel. The movable part penetrates through the flexible separation component and enters the air channel and the fuel gas channel and performs a movement to change the first and second sectional flow area.