Methods and apparatus for improved energy efficient control of an electric arc furnace fume extraction system

A fume extraction system for containing fumes generated by a furnace, comprising:

• a combustion zone including a combustion chamber and an inlet that is connectable with an exhaust outlet of the furnace so as to receive an exhaust gas stream emerging from the furnace outlet, the exhaust gas stream including explosive gases that undergo combustion reactions within the combustion zone;
• a duct section aligned downstream from the combustion chamber to deliver the exhaust gas stream toward a system vent outlet;
• a suction unit arranged within the system to establish a negative pressure within the furnace, the combustion zone, and the duct section so as to draw the exhaust gas stream from the furnace outlet and through the combustion zone and duct section during system operation;
• an adjustable exhaust damper disposed at a selected location within the system between the inlet of the combustion zone and the suction unit;
• and
• a control system to selectively control the negative pressure applied to the furnace, the combustion zone and the duct section, the control system comprising:
• a gas sensor device disposed at a selected location within the system to measure a concentration of at least one of oxygen, carbon monoxide, hydrogen, carbon dioxide, water and nitrogen within the exhaust gas stream;
• and
• a controller in communication with the gas sensor device and the exhaust damper, wherein, during system operation, the controller effects opening and closing of the exhaust damper to selectively modify the negative pressure within the furnace, the combustion zone and the duct section based upon gas concentration measurements received from the gas sensor device.