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.

Exemplary embodiments are disclosed of systems including electronic differential pressure sensors for electronically controlling stepper gas valves to modulate fuel flow in PAM combustion systems (e.g., PAM furnace systems, etc.). Also disclosed are exemplary methods for electronically modulating fuel flow in pressure augmented modulation (PAM) combustion systems.

A method of preventing blockage of circulating bed material in a circulating fluidized bed reactor includes collecting a continuously flowing bed of solid particles in a gas lock in a return leg of a reactor, measuring gas lock bed pressure values within the bed of the particles, generating a gas lock bed height indication signal on the basis of measured gas lock bed pressure values. A definition stage includes defining and storing to a control system a range of normal gas lock bed height indication signals, formed in normal circulation flow conditions, as a function of the reactor load, and defining and storing to the digital control system a reactor load dependent alarm criterion. The method includes comparing a current gas lock bed height indication signal with the reactor load dependent alarm criterion, and decreasing the reactor load if the current indication signal fulfils the reactor load dependent alarm criterion.

A method for the failsafe and lean ignition of a fuel gas-air mixture on a gas burner (6), which is mixed in a mixing device (4) arranged upstream of the gas burner (6). A control valve (2) along the fuel gas flow path has an actuator (21) and a throttle element (23), moved by the actuator (21), for the closed-loop control of a flow rate of the fuel gas flowing into the mixing device (4). A test is performed to determine whether the throttle element (23) is in the throttle reference position when the actuator (21) is in the actuator reference position. The throttle element (23) is moved in a flow rate-increasing manner starting at a start time (tD). The flow rate-increasing movement of the throttle element (23) is stopped as soon as at least one of multiple predetermined termination conditions occurs.

A specialized miniature housing installable between a source of gas and gas burners provides an aftermarket safety system for a gas grill. The system prevents accidental accumulation of gas in an enclosed volume within or around an unignited grill, thereby reducing or eliminating the risk of explosion. The housing includes a microcontroller coupled to an internal flow sensor, an external temperature sensor, and a valve. In response to signals received from the sensors, the microcontroller commands the valve to remain open only when positive flow through the housing is coincident with sufficient temperature at the burners. Otherwise, or upon loss of power, the valve closes to cut off gas supply to the grill.

A motor controller for a draft inducer motor that operates an inducer blower in a furnace is provided. The motor controller includes a communication interface operable to receive a signal from a system controller. The signal represents a command to operate the draft inducer motor. The motor controller includes a processor operable to operate the draft inducer motor in accordance with a predefined motor speed profile during at least one of an ignition stage and a combustion stage of the furnace.

A process for controlling a combustion air delivery system of an oil fryer, the process comprising: (i) activating the combustion air delivery system; (ii) determining if a current target RPM is able to activate an air pressure sensing switch of the combustion air delivery system; (iii) if the current target RPM is able to activate the air pressure sensing switch, then a heating controller uses the current target RPM for heating; and (iv) if the current target RPM is not able to activate the air pressure sensing switch due to fan filter clogging or any other reduction in air supply in the combustion air delivery system, then the process for controlling the combustion air deliver system will conduct an initial calibration sequence to determine a new higher target RPM which will increase the air supply in the combustion air deliver system.

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.

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.