Various embodiments of the teachings herein include a mixer disposed in a fuel gas combustion system and mixing air and fuel gas to form flammable mixed gases. The mixer may include: a Venturi tube having an air inlet, a fuel gas inlet, a gas mixture outlet, a central axis direction, and a throat positioned between the air inlet and the gas mixture outlet in the central axis direction, wherein the fuel gas inlet is disposed at the throat; and an adjustment component disposed in the Venturi tube downstream of the throat, the adjustment component drivable to move towards or away from the throat in the central axis direction, thereby changing a flow area of gas in the Venturi tube. The adjustment component comprises a conical valve plug with a conical outer surface thereof at a side facing towards the throat and fitting an inner surface of the Venturi tube.

This application relates to a method for controlling the combustion in furnace systems, wherein an oxygen coefficient is determined from the temperature in a combustion chamber area and/or in the waste-gas flues of the furnace system and on the basis of an energy balance of the combustion process in the furnace system, the combustion air and the waste gas, and said oxygen coefficient is used to control the combustion material flows and therefore the thermal output and also the combustion quality. The invention relates to a device for feeding combustion air in the furnace system, which device has a chamber, which on a first side has a main duct for feeding ambient air and/or air from the chimney system and on a second side has a pane-washing air duct and a secondary-air duct, both the pane-washing air duct and the secondary-air duct.

A flow control device for an appliance including a burner and a blower for delivering a pre-mixed mixture of air and gas to the burner includes a flange defining an opening through which the pre-mixed mixture of air and gas flows from an outlet of the blower to the burner. A damper plate is provided in the opening downstream of the blower for increasing a static pressure at the outlet of the blower during ignition of the burner.

A fluid heating system including a burner unit is operated based on feedback control loops. The fluid heating system comprises a burner unit configured to heat a fluid, a sensor configured to sense a characteristic of the appliance, and a controller coupled to the burner unit and the sensor. The controller includes an electronic processor and a memory. The controller is configured to receive a first signal corresponding to the characteristic from the sensor, determine, based on the first signal, a first feedback loop control, control combustion of the burner unit based on the first feedback loop control, determine, based on the first feedback loop control, a second feedback loop control, and control combustion of the burner unit based on the second feedback loop control.

A premixing apparatus in which a downstream end of a gas supply passage is connected to a gas suction section disposed in an air supply passage on an upstream side of a fan, is provided with: a butterfly valve driven by a stepping motor, for changing over, between high and low, a ventilation resistance in that section of the air supply passage which is on an upstream side of the gas suction section; a changeover valve for changing over, between high and low, a ventilation resistance in that section of the gas supply passage which is on an upstream side of a flow control valve; and an interlocking mechanism which opens or closes the changeover valve in interlocking with the rotation of the butterfly valve and which maintains the changeover valve in a closed state until the butterfly valve has rotated from the closed posture toward the opening side by a predetermined angle. Flame failure and poor combustion are prevented at the time of changing over the butterfly valve and the changeover valve from closed posture to opened posture.

When the butterfly valve is rotated from the closed posture into the opened posture, a driving frequency of the stepping motor is made higher, until the butterfly valve has rotated from the closed posture toward the opening side by a predetermined set angle, than the driving frequency during the subsequent operation of the butterfly valve.

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 gas fired burner control system for a kiln for firing for instance ceramic items. The system including a plurality of operating modes, with the system being configured such that during a firing cycle the system can move between operating in different modes.

A heat exchange flue, having a top flue gas chamber (1), a bottom flue gas chamber (10) and a heat exchange section (H) located therebetween. The heat exchange section (H) comprises a heat exchange tube bundle (4) located in the middle, and a left side flue (5) and a right side flue (12) which are located at two sides of the heat exchange tube bundle (4). The axis of the heat exchange tube bundle (4) is positioned in a vertical plane extending substantially forward and backward, allowing the flue gas to laterally flush against the surfaces of heat exchange tubes. The left and right side flues (5, 12) are in a vertical box shape, the flues are each provided with a plurality of flue gas dampers (3) which are vertically arranged at intervals in a substantially horizontal alignment. Each of the flue gas dampers (3) is provided with a flue gas damper frame (13) for defining a flue gas port (2) and a flue gas port opening/closing device capable of selectively opening and closing the flue gas port (2). The flue gas damper frames (13) are hollow out and horizontally arranged, and have an outer contour consistent with the sectional shape of the left and right side flues (5, 12), the peripheral edges thereof are respectively connected to a peripheral flue gas wall in an airtight manner, and the parts thereof corresponding to the heat exchange tube bundle (4) are connected to a substantially horizontal flue gas shield plate (6) in an airtight manner. The flue structure can adjust the working load to the greatest extent to ensure the flue gas temperature and prevent condensation.

A valve actuator (10) includes an electric motor (12) that opens, and also closes if need be, the valve via a gearing (15). A voltage supply device (19) has an input rectifier circuit and a buffer device (24) connected thereto, for example in the form of a capacitor C. From the voltage buffered by the capacitor C, a motor control circuit (25) obtains the energy for operating the electric motor (12). To prevent the valve (11) from being kept open too long after the voltage supply at the input (20) has been switched off, a switch-off device (34) is provided, which, after elimination of the voltage at the input (20), cuts off the energy flow from the voltage buffer device (24) to the electric motor (12).

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.