A damper for a furnace, the damper including an air port damper body engaged to an air port opening of a furnace; and at least one velocity plate in hinged engagement to the air port damper body so that an air controlling end surface of the at least one velocity plate is substantially aligned to a wall of the furnace at the air port opening when the at least one velocity plate is in a fully opened position.

The disclosed technology includes a device for extending the turndown ratio of a gas-fired burner system. The device can comprise a variable area device configured reduce the amount of fuel and air passed to the burner during low output conditions by adjusting the cross-sectional area of the passage between the blower and the burner. The variable area device can be controlled by an actuator that adjusts the position of the variable area device. The actuator can be manually controlled, mechanically controlled, or electronically controlled.

Air Assisted Enclosed Combustion Devices (AAECD) and methods are disclosed that provide maximum destruction efficiency of VOC's and methane greenhouse gases produced by oil production, site processing, storage, and transmission operations and produces no visible emission (smoke, soot, particulates) in the process. An exemplary AAECD may include a housing with an outer housing and a burner housing separated by an air gap. The AAECD is provided with a burner assembly, a blower assembly, and a suite of sensors in communication with an electronic control module having logic configured to receive input signals from the sensors, calculate an actual fuel-air ratio using the received input signals, compare the actual fuel-air ratio to a fuel-air ratio setpoint, and adjust a position of a throttle valve to control a rate and volume of air from a blower motor to the burner if the actual fuel-air ratio and the fuel-air ratio setpoint are different.

Methods and systems for programming and controlling a control system of a gas valve assembly. The methods and systems include programming a control system in an automated manner to establish an air-fuel ratio based at least in part on a burner firing rate. The established air-fuel ratio may be configured to facilitate meeting a combustion constituent set point of combustion constituents in the combustion exhaust. The methods and systems include controlling operation of a combustion appliance based on closed-loop control techniques and utilizing feedback from a sensor measuring combustion constituents in exhaust from a combustion chamber in the combustion appliance. The combustion constituents on which control of the combustion appliance may be determined include oxygen and/or carbon dioxide.

A system for controlling a combustion appliance based on one or more localized environmental factors and an inlet/exhaust system enclosed within a single enclosure. The control system includes an electrically controlled fuel valve, coupled to a source of combustion appliance fuel, and responsive to a fuel valve control signal, for controlling the flow of fuel to the appliance. An air pressure detector is disposed in an area proximate the combustion appliance and configured for detecting negative air pressure in the proximate area and in response for providing a negative air pressure detection signal to a relay which will deactivate the fuel valve until negative air pressure is not present thereby preventing operation of the combustion appliance. Further, if negative air pressure is detected, the relay energizers a makeup air device to bring an outside air into the area near the combustion appliance.

Techniques for controlling a solid fuel combustion appliance, e.g., a wood burning stove, are disclosed. A control system measures an exhaust gas temperature of airflow through an outlet of the solid fuel combustion appliance. The control system determines a derivative of the exhaust gas temperature with respect to time. The derivative of the exhaust gas temperature with respect to time is compared to a predetermined threshold. The control system modulates the inlet damper in response to determining that the derivative of the exhaust gas temperature with respect to time reaches the predetermined threshold.

This application is directed to a device and method for providing a variable orifice restrictor to an air induction system to achieve an improved turndown ratio of an airflow rate. The devices of the invention improve turndown ratio by relying on a pressure differential.

An electronic control device includes: a flow rate calculation unit that calculates a flow rate of intake air based on an output signal of a flow rate measurement device assembled to an intake pipe; a flow rate correction value calculation unit that calculates an average value, a maximum value, and a minimum value of the flow rate of the intake air, calculated by the flow rate calculation unit, during a predetermined period, and an amplitude of a signal with one or more frequencies equal to or higher than a fundamental frequency of the output signal of the flow rate measurement device and included in the output signal of the flow rate measurement device, and calculates a correction value for the flow rate of the intake air based on calculation results; and a flow rate correction unit that corrects the flow rate of the intake air based on the correction value.

A method is provided for controlling airflow into a furnace that employs a velocity type damper. In one embodiment, the method for controlling airflow may include engaging a velocity type damper to an air port opening of a furnace. The velocity type damper includes at least one air controlling surface that is positioned proximate to a wall of the furnace at the air port opening so that air velocity exiting the at least one air controlling surface is substantially equal to the air velocity entering the air port opening to the furnace. The method may further include adjusting a cross sectional area through the velocity type damper to control air velocity into the furnace through the air port opening.

In a gas hot water heater, changes of the signal output of an A/F sensor are calibrated in the atmosphere, in which the A/F sensor detects an oxygen concentration in a combustion tube. The gas supplied via a gas supply pipe is injected, together with in-taken air, into a combustion tube, which is incorporated in a hot water supply tank, via an injection unit. A proportional valve controls a combustion state in the combustion tube based on the detected oxygen concentration to thereby heat water supplied in the hot water supply tank. A purging process is performed to supply air into the combustion tube, at a timing between an extinguishment operation first performed after the ignition the gas mixture in the combustion tube and a re-ignition operation. Changes of signal output characteristics of the A/F sensor are subject to the calibration after the purging process.