Arc furnace fume collection method

Abstract

The present invention provides a system and method for collecting fumes from an arc furnace of the type typically used in metal foundries. The system provides an electrode hood with extended sides for improved collection of fumes from the vicinity of the electrodes. It also provides a movable spout hood for collection of fumes when metal is tapped. A combination of a tilting manifold and stationary duct are used to maintain a path for collecting fumes throughout the entire range of motion of the furnace. The stationary duct has a group of dampers that open and close as the furnace tilts. Variable position dampers may be provided at the electrode hood and furnace door. In the bag house, there is a dust containment assembly to limit the movement of the collected dust. A variable speed fan may be used with the system. One method of the invention involves determining the pressure differential upstream and downstream of the filter bag, determining the fan speed, and closing a damper downstream of the filter to clean the filter bag when the determined values for the pressure differential and fan speed match previously set values. The entire system may be controlled by a programmable logic element to maximize efficiency. Another method involves the steps of adjusting the electrode hood damper, spout hood damper and door hood damper in response to furnace conditions.