A combustion staging system has: a splitter; pilot and mains fuel manifolds; mains flow control valves; and fuel servo line. Each mains flow control valve has a chamber containing a piston, the chamber to a piston mains side fed by the mains fuel manifold, and the chamber to a piston servo side fed by the servo line. The piston has an open pilot-and-mains position allowing flow from the chamber mains side to the respective injector mains discharge orifice. The piston prevents flow from the chamber mains side. The piston is movable under a pressure change in the servo line relative to the mains fuel manifold. The system has a servo pump and a hydraulic motor driving it. The servo pump changes fuel pressure. Motive power for the hydraulic motor is fuel diverted from a fuel pump high pressure output, the motor returning the diverted fuel to a low pressure input.

A modulating burner apparatus includes a burner and a blower placed upstream of the burner. A venturi is placed upstream of the blower. A damper valve is placed upstream of the venturi. The damper valve has an open position and a restricted position. A smaller gas valve and a larger gas valve are communicated with the venturi. A controller is operably associated with the system to select a position of the damper valve and to select the appropriate one of the gas valves so as to provide a low output operation mode and a high output operation mode, which in combination provide an overall turndown ratio of at least 25:1.

A double flow rate gas solenoid valve has an inlet and at least a first outlet in a housing. First and second solenoids are selectively operable relative to first and second valve seats to establish first and second gas flow paths, respectively. The second flow path has a restriction thereby resulting in a lower gas flow rate through the second flow path than the first flow path. When connected to a common inlet of a burner, at least two, if not three flow rates can be provided by the valve.

A two-stage fluid control valve includes a first stage mechanical control valve movable between an open position and a leak-free closed position, and a second stage microvalve configured to control the flow of fluid through a fluid outlet of the two-stage fluid control valve when the first stage mechanical control valve is in the open position.

A dual fuel heating system can be used in a gas appliance. A dual fuel heating system can have a fuel selector valve for selecting between a first fuel and a second fuel different from the first. The dual fuel heating system can include a regulator unit configured to regulate the pressure of the two different fuels. The selector valve determines which flow path for which fuel is open and which is closed.

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.

A cooking appliance is provided. The cooking appliance may include a burner pot having a plurality of mixing spaces and a gas valve device to adjust a flow rate of a gas to be supplied into at least one mixing space of the plurality of mixing spaces.

This disclosure relates generally to valves, and more particularly, to gas valve assemblies. In one example, the valve assembly may include a valve body with a fluid path, one or more valves or valve sealing members positioned across the fluid path, and one or more pressure sensors in fluid communication with a fluid path of the valve assembly. The valve assembly may include a valve controller in communication with the pressure sensors, where the valve controller may be configured to compare a measure related to a pressure sensed by the one or more pressure sensors to a pressure threshold value (e.g., a high pressure threshold value, a low pressure threshold value, or other pressure threshold value). If the measure surpasses the threshold value, the valve controller may provide a predetermined output signal indicating a pressure event has occurred, such as a high or low gas pressure event.

Gas flow controllers for use in gas fired apparatus including a pilot burner and a main burner are described. A controller includes a pilot valve moveable between a closed position and an open position to provide selective fluid communication between a gas inlet and the pilot burner, a main burner valve providing selective fluid communication between the gas inlet and the main burner, an actuator configured to open the pilot valve, a flow controller valve operable to open and close a fluid flow path between the gas inlet and a back side of the main burner valve upon actuation of the actuator, and a decoupling mechanism. The decoupling mechanism is configured to connect the actuator to the pilot valve and to selectively disconnect the actuator from the pilot valve when the actuator is actuated and a pressure differential across the pilot valve exceeds a threshold pressure limit.

A universally applicable regulation function is provided for a gas-operated heating device with more than one burner. The function facilitates start-up, regulation, and deactivation processes. A first valve and a second valve are connected together in a gas-tight manner. The first valve has an ignition lock which closes the main gas flow in the event of an ignition, a thermoelectric ignition fuse, a thermostat, and optionally an integrated pressure regulator. The start-up of the first valve allows the activation and deactivation of the gas flow. The first valve has two gas outlets, a first outlet for connecting the second valve, wherein the first outlet is located downstream of the ignition fuse and the optional pressure regulator and upstream of the thermostat, and a second outlet downstream of the thermostat, the second outlet leading to a first burner. The second valve is a thermostat. The first outlet of the first valve is connected to the inlet of the second valve, and the outlet of the second valve is connected to a second burner.