The invention is in the field of boiler control and relates to a control method for the operation of a combustion boiler, comprising providing a predetermined upper limit (VF,max) for the flue gas velocity in at least one location of the boiler; monitoring the flue gas velocity (VF) during the combustion of fuel in said at least one location of the boiler; comparing the flue gas velocity (VF) with the predetermined upper limit (VF,max); decreasing the thermal load of the boiler if the flue gas velocity exceeds the predetermined upper limit (VF,max). The invention also relates to a control system configured to execute the control method.

A gas manifold allows each distribution chamber to be fed with fuel gas at an appropriate flow rate irrespective of an increase in the number of distribution chambers included in the gas manifold. A gas manifold distributes fuel gas flowing in through an inlet to a plurality of distribution chambers through a main channel. The main channel includes a flow guide that guides the fuel gas toward a maximum distribution chamber and reduces the fuel gas flowing into other distribution chambers. This allows fuel gas at a sufficient flow rate to be fed more easily to the maximum distribution chamber than to the other distribution chambers for a larger number of distribution chambers included in the gas manifold, allowing the plurality of distribution chambers to be fed with fuel gas at appropriate flow rates.

A fuel burner includes a tube extending from a first end to a second end and including a central passage and fluid directing structure for directing a mixture of air and combustible fuel radially through the tube. The fluid directing structure collectively defines a total flow area. A blocking member is axially movable within the central passage between a first condition blocking a first percentage of the total flow area and a second condition blocking a second percentage of the total flow area different from the first percentage to control the flow of the mixture of air and combustible fuel through the fluid directing structure from the first end to the second end of the tube to be ignited.

A flame detection system is designed to detect leakage in flame sense circuits. The flame detection system includes a flame sensor, an amplifier, a detection circuit, and a microcontroller. Flame sense circuitry use operational amplifiers that needs negative voltage supply for its operation. Negative supply voltage properly measures negative input signals. Once a leakage current in the flame detection system is determined a shutdown signal is provided to shut down a flame sensor when the leakage current condition is determined.

Described is a device (11) for controlling the combustion of a burner (1), comprising: first means (12) for measuring the fuel flow rate (Vg); second means 13 for measuring the flow rate of the comburent (Va) first operator means (14) for controlling the opening of an inlet valve (5) as a function of the quantity of fuel to be supplied to the burner (1); second operator means (15) for controlling the comburent flow regulator means (8) as a function of the quantity of comburent to be supplied to the burner (1); According to this invention, the device (11) comprises a unit (16) for controlling the first operator means (14) and the second operator means (15) as a function of the values measured by the first measuring means (12) and by the second measuring means (13).

A flame detection system is designed to detect leakage in flame sense circuits. The flame detection system includes a flame sensor, an amplifier, a detection circuit, and a microcontroller. Flame sense circuitry use operational amplifiers that needs negative voltage supply for its operation. Negative supply voltage properly measures negative input signals. Once a leakage current in the flame detection system is determined a shutdown signal is provided to shut down a flame sensor when the leakage current condition is determined.

A burner supporting primary and secondary combustion reactions may include a primary combustion reaction actuator configured to select a location of the secondary combustion reaction. A burner may include a perforated flame holder structure configured to support a secondary combustion reaction above a partial premixing region. The secondary flame support location may be selected as a function of a turndown parameter. Selection logic may be of arbitrary complexity.

A combustion system such as a furnace or boiler includes a perforated reaction holder configured to hold a combustion reaction that produces very low oxides of nitrogen (NOx).

A method includes identifying a first steady-state gain associated with a relationship between a characteristic of a furnace and a setpoint used by a controller that is configured to control the characteristic of the furnace, The first steady-state gain is identified using data collected when the furnace is not suffering from flooding. The method also includes identifying a second steady-state gain associated with the relationship during operation of the furnace. The method further includes comparing the first and second steady-state gains and identifying actual or potential flooding of the furnace based on the comparison.

A combustion system such as a furnace or boiler includes a perforated reaction holder configured to hold a combustion reaction that produces very low oxides of nitrogen (NOx).