To enhance an energy conservation effect by accompanying a control operation for intending to hold a predetermined pressure in a furnace with a regulating operation for regulating an opening of an exhaust gas damper based on a rotational speed of an exhaust gas fan, thereby enlarging a control range.
A signal regarding an internal pressure in a furnace body 11 is sent from a pressure oscillator 21 to a control calculator 22 to instruct, so that the calculator 22 generates an inverter drive output to an inverter control unit 23 for driving an exhaust gas fan 14 for the fan 14 to rotate at a previously programmed rotational speed in response to a deviation from a target value. In the combustion furnace having the fan 14 and an exhaust gas damper 4 at an exhaust gas channel, the control operation for tending to hold a predetermined pressure in the furnace by controlling a flow rate under the control of the speed of the fan 14 is accompanied with an operation for PID controlling an opening of the damper 4 based on the speed of the fan 14.
Kawaguchi, Kenji
Ito, Yasuhiro
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