PURPOSE: To improve the heat transfer rate of the whole of the cooling part of a furnace electrode by a method wherein a furnace bottom electrode is formed in a sectional shape having a long peripheral length, and the lower end part, protruded outwardly of a furnace bottom shell, of the furnace bottom electrode is cooled by means of an air flow collided with the electrode long shaft side at right angles.
CONSTITUTION: A number of furnace bottom electrodes 30 made of a steel rod having a small size are embedded in a furnace bottom refractory 28' at a furnace bottom 16 of an air-cooled type DC electric furnace. In which case, the lower end protruded outwardly of the furnace is formed such that the air-cooled furnace bottom electrode 30 is made of a flat steel in the shape of a long side, and air cooling is effected in a way to cause an air flow to flow at right angles with a long shaft. The lower end part of the furnace bottom electrode 30 is cooled as air fed through an air feed pipe 34 connected to the central part of an electrode support plate 32 flows through a gap between an electrode support plate 32 and a bottom plate 16a from the upper stream side to the downstream side. The furnace bottom electrodes 30 are radially arranged toward a central point so that an air flow flows at right angles with a long shaft. The air cooling improves the average heat transfer rate of the whole of the cooling part of the furnace bottom electrode 30.
MIZOTA HISAKAZU
TAKASHIBA NOBUMOTO
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