A method for evaluating a quasi-stationary pressure difference detectable by a sensor at a gas boiler. The gas boiler has a mixing device (4), a fan (5), a main flow regulator (3), a control valve (2) and a safety valve (1). The sensor detects a differential pressure between a pressure (p2) at a measuring point upstream of the main flow regulator (3) and downstream of the control valve (2) and a reference pressure (p0, p1) at a reference measuring point. The sensor transmits a signal to an electronic evaluation system. The electronic evaluation system compares the differential pressure during a pre-purge phase, wherein the safety valve (1) is closed, with the differential pressure after the pre-purge phase and detects an error by the comparison.

This fuel calculation device comprises: a remaining fuel amount calculation unit that periodically calculates and stores an approximate value of the remaining fuel amount on the basis of the measurement value of the remaining fuel amount remaining in a fuel container, and the fuel flow rate of fuel supplied from the fuel container; a failure determination unit that determines whether a remaining fuel amount meter that outputs the measurement value of the remaining fuel amount has failed; and a display control unit that controls so as to display the measurement value of the remaining fuel amount when the remaining fuel amount meter has not failed, and to display the approximate value of the remaining fuel amount when the remaining fuel amount meter has failed.

A method for lowering emissions that result from fuel combustion in a boiler may include obtaining a fuel composition, an air composition, and ambient conditions; determining, based on the fuel composition, the air composition, and the ambient conditions, a temperature margin sufficient for reliable combustion, and a minimum adiabatic flame temperature (AFT_LFL) for sustainable combustion within the boiler; establishing a combustion temperature control envelope bounded by the minimum AFT_LFL plus the temperature margin sufficient for reliable combustion, and by a threshold temperature below which thermal NOx formation is minimized; controlling, via a feedforward cascade control algorithm, an injection rate of the fuel into the boiler via a fuel injection system and an injection rate of air into the boiler via an air injection system; and automatically adapting the feedforward cascade control algorithm and associated control setpoints to remain within the combustion temperature control envelope.

A device for controlling a fuel-oxidizer mixture for a premix gas burner includes: an intake duct, including an inlet, a mixing zone, and a delivery outlet; an injection duct; a gas regulating valve, located along the injection duct; a fan, located in the intake duct to generate therein a flow of the oxidizer fluid or of the mixture; a control unit, configured for generating drive signals; a sensor unit, configured to detect a first differential pressure, between a first detecting section, located in the intake duct upstream of the mixing zone in the direction of inflow and a second detecting section, located in the intake duct downstream of the mixing zone in the direction of inflow, and configured to detect a second differential pressure, between the first detecting section and a third detecting section, located in the injection duct between the gas regulating valve and the mixing zone.

A system and method for optimizing combustion in boiler. The optimization of the combustion in the boiler involves obtaining various data relating to the flow of fuel and air to burners of the boiler and the flame in the burner zone of the boiler that is generated from the introduction of the fuel and air into the burner zone. The data is used to determine air flows to the burners. The data and air flows are used to balance air and fuel at individual burners by manipulating air to match the fuel flow. The balancing of air and fuel at individual burners by manipulating air to match the fuel flow uses a guided search optimization algorithm that mixes stoichiometry determinations with a custom search algorithm that accounts for measurement inaccuracies and unexpected interactions between burners.

Method for operating a gas burner appliance (10) comprising: a combustion chamber (11), an ignition device (27), a fan (14), a gas safety valve unit (19) assigned to the gas duct (16), an electric gas flow modulator (18) assigned to the gas duct (16), a sensor (21) positioned between the gas safety valve unit (19) and the gas flow modulator (18), wherein the gas burner appliance (10) is operated to determine the gas family of the gas of the gas/air mixture by the following steps: Before the gas burner appliance becomes started measuring the ambient air pressure by the sensor (21), wherein the ambient air pressure is measured when the safety valve unit (19) is closed, the gas flow modulator (18) is opened and the fan (14) is stopped. When the gas burner appliance (10) becomes started running the fan (14) at a defined fan speed, increasing the opening of the gas flow modulator (18) while activating the ignition device (27) trying to ignite the gas/air mixture until the activation of ignition device results into a combustion of the gas/air mixture. Determining from the fan speed of the fan (14) and from the measured ambient air pressure an air volume flow. Measuring the gas pressure by the sensor (21) when the safety valve unit (19) is opened, the gas flow modulator (18) is opened and the fan (14) is running. Determining from the opening of the gas flow modulator (18) at which the combustion started and from the measured gas pressure a gas volume flow. Determining a ratio between the gas volume flow and the air volume and from said ratio the gas family of the combusted gas.