A gas valve unit for setting a gas volumetric flow to a twin-circuit gas burner of a gas appliance includes a valve body having a gas inlet and two gas outlets, and a control mechanism for adjusting the gas volumetric flow to at least one of the gas outlets in a multiple-stage manner. The control mechanism has a zero position in which the gas volumetric flow to the gas outlets is interrupted, and a switching position which is adjacent to the zero position and in which the gas volumetric flow is set to a maximum value.

A shut-off valve that has a closure orifice, a closure member to open and close a gas passage through the shut-off valve, an electromagnetic actuator including a movable assembly attached to the closure member, the closure member, and an electromagnetic filed generator magnetically associated with the movable assembly. The shut-off valve also includes a manual actuator for acting on the movable assembly, the manual actuator comprising an open position in which it is decoupled from the movable assembly, the electromagnetic actuator thus being able to act on the closure member to cause its closure.

A shut-off valve that has a closure orifice, a closure member to open and close a gas passage through the shut-off valve, an electromagnetic actuator including a movable assembly attached to the closure member, the closure member, and an electromagnetic filed generator magnetically associated with the movable assembly. The shut-off valve also includes a manual actuator for acting on the movable assembly, the manual actuator comprising an open position in which it is decoupled from the movable assembly, the electromagnetic actuator thus being able to act on the closure member to cause its closure.

A control valve may include a fluid inlet, a plurality of fluid outlets, and a plurality of magnets. One of the plurality of magnets controls fluid flow for each of one of the plurality of fluid outlets. One of the plurality of magnets controls fluid flow for the remaining of the plurality of magnets. When the magnet controlling fluid flow for the remaining of the plurality of magnets is energized, fluid flow is permitted to the remaining of the plurality of magnets. When the remaining of the plurality of magnets are energized, fluid flow is permitted to the respective plurality of fluid outlets.

For monitoring burner operation, such as in a refinery, boiler or the like, an acoustic sampler such as a piezo-electric microphone is located in a position to record an acoustic sample of the burner operation. The acoustic sample can be processed to determine whether the burner is operating normally or has suffered a flame out condition. Remedial actions can be undertaken to control the fuel supply to the burner if a flame out condition has been detected.

A method for regulating the combustible mixture such as air/gas, air/methane gas or the like fed to a burner, the method including measuring a flame signal correlated with the composition of the mixture fed by feed members controlled by a combustion controller arranged to regulate the combustion on the basis of the flame signal. During burner operation the mixture feed conditions are modified within a narrow time interval to obtain a flame signal variation; a ratio between values of this the flame signal at the end and at the beginning of the interval is compared with a predetermined reference value; and, on the basis of the deviation of this ratio from the reference value, the flame set point is regulated, as consequently is the air or gas of the mixture if this is rendered necessary.

A control gas ball valve for high pressure gas cooking appliances provides a linear surface slot along its rotation direction. When turned by a control knob and enters a gas inlet, the said surface slot is able to channel gas input to a hole that connects said surface slot to the center of the valve ball. The gas in the center of the valve ball is directed away to a burner for cooking purposes. The said linear surface slot is able to provide constant flowrate slope for continuously variable power adjustment and a maximum power plateau. These are the most desirable features in residential cooking.

A switching assembly of a gas stove includes a regulating valve, a knob, a stop board, and a restricting device. The regulating valve has a valve member and a regulating member, which is rotatable to regulate a gas flow through the valve member. The knob is connected to an end of a shaft which is connected to the regulating member with an opposite end thereof, and therefore the regulating member can be rotated by turning the knob. The stop board is located between the valve member and the knob, wherein the stop board has a curved slot, which has a first stop portion and a second stop portion. The restricting member is movable in the curved slot and is restricted by the first or the second stop portions. When the restricting member touches the first stop portion, the switching assembly allows larger gas flow to flow through.

A method is described for controlling a furnace containing a plurality of catalyst-containing tubes heated by a combustion gas generated by a plurality of burners, said method comprising the steps of: (i) measuring path-averaged combustion gas temperatures on multiple paths through the furnace using tunable diode laser absorption spectroscopy, (ii) periodically measuring temperatures of surfaces within the furnace to obtain periodic surface temperature information, (iii) entering the path-averaged combustion gas temperatures and periodic surface temperature information into a computer model of the furnace, said model comprising parameters for controlling the furnace; and (iv) using the computer model and the temperature information to obtain optimised parameters for controlling the furnace. A system for performing the method is also described.

A control device for gas appliances comprises at least one control module (20) having a supporting structure that can be associated to a gas tap (10) and defines a housing, contained within which is at least one first part of a circuit arrangement. The control module (20) comprises a command element operable by a user for activating at least one timing function and/or a function of ignition of a gas burner. The first part of the circuit arrangement comprises control elements, electrical-interconnection elements, and detection elements (45) configured for detecting actuation of the command element and supplying corresponding signals to the control elements. The circuit arrangement comprises further control and/or command elements (PSD, IS, F, LE, BC, ISC) and/or an auxiliary module (PSD).