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.

A fully automatic and efficiently energy-saving barbecue grill is disclosed. The barbecue grill comprises: a grill body, having side walls and a top plate thereon, wherein a grill space is formed inside and a smokeless heating pipe is arranged in the grill space; a gas control device, installed in the grill body, guiding fuel gas to burn in the grill space to heat the smokeless heating pipe; and an automatic grill device, installed in the grill body, rotating food periodically to get grilled by the heat from the smokeless heating pipe.

The premixing device includes a first and a second venturi having a pressure reducing portion for air, and a gas supply passage for supplying fuel gas to the venturis, and generates air-fuel mixture by mixing fuel gas with air flowing in the venturi by using a fan and supplies the air-fuel mixture to a burner. A first and a second nozzles for reducing pressure of fuel gas are disposed in the gas supply passage, and the first and the second nozzles are formed in the same nozzle shape as the pressure reducing portion of the first and the second venturis.

A method of controlling a premixing apparatus that mixes fuel gas with air and supplies thus obtained air-fuel mixture, through a fan to a burner, includes at a time of changing over to a small-capacity state in which a first ventilation resistance in an air supply passage is increased and also in which a second ventilation resistance in a gas supply passage is increased, rotating a butterfly valve down to a closing side stop angle; and at a time of changing over to a large-capacity state in which the first ventilation resistance in the air supply passage is decreased and also in which the second ventilation resistance in the gas supply passage is decreased, rotating the butterfly valve up to an open-side stop angle.

A fluid mixer configured to stably supply a mixed fluid having a desired mixing ratio, and which can be reduced in size. This fluid mixer includes a Venturi tube having a constriction section at which the flow path area is reduced, the Venturi tube having formed therein a first inflow opening and a second inflow opening through which a second fluid flows into a low-pressure region produced due to an increase in fluid velocity when a first fluid passes through the constriction section. A valve body that is disposed within the Venturi tube, the valve body closing due to the pressure of the first fluid passing through the Venturi tube and changing the flow path area of the Venturi tube, blocking off the first inflow opening when closed, and opening the first inflow opening when opened; and a biasing part (elastic body) applying a biasing force in the valve closing direction of the valve body.

A method for operating a combustion arrangement, the combustion arrangement including at least one combustor chamber arranged in a double-walled housing, at least one inlet configured to supply a fuel to the at least one combustion chamber, at least one outlet for letting exhaust air from the at least one combustion chamber, and at least one air channel configured to feed supply air into the housing, wherein the housing includes an inner wall and an outer wall which jointly define an intermediate space between each other, wherein an air inlet opening that cooperates with the at least one air channel is arranged in an upper end section of the outer wall so that the supply air is feedable through the at least one air channel into the intermediate space.

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 furnace according to an embodiment of the present disclosure includes: a mixer for mixing air and a fuel gas, which are introduced through an intake pipe and a manifold, respectively, to form a mixture; a mixing pipe through which the mixture, having passed through the mixer, flows; a burner assembly for producing a combustion gas by burning the mixture having passed through the mixing pipe; a heat exchanger through which the combustion gas flows; an exhaust pipe through which an exhaust gas, as the combustion gas having passed through the heat exchanger, is discharged outside of the gas furnace; and an inducer for inducing a flow of a fluid through the intake pipe, the mixer, the mixing pipe, the burner assembly, the heat exchanger, and the exhaust pipe. In this case, the mixer has a front end connected to the intake pipe, a rear end connected to the mixing pipe, and a side surface connected to the manifold.

This application is directed to a device and method for providing a variable orifice restrictor to an air induction system to achieve an improved turndown ratio of an airflow rate. The devices of the invention improve turndown ratio by relying on a pressure differential.

An injet for a gas burner includes a first gas orifice and a second gas orifice. An injet body defines an air passage and a gas passage. The first and second gas orifices are mounted to the injet body. A pneumatically actuated gas valve blocks a flow of gaseous fuel through the gas passage to the second gas orifice in a closed configuration. The pneumatically actuated gas valve is configured to adjust from the closed configuration to an open configuration in response to a flow of air through the air passage. A flow restriction body is disposed upstream of the pneumatically actuated gas valve. The flow restriction body defines a through hole via which air is flowable to pneumatically actuated gas valve.