| 摘要 |
PURPOSE:To prevent breakout generated by base metal surrounding electrodes, by alternately shifting tip positions vertically of a plurality of electrodes to be electrically conducted upon contact with a molten metal while the circumference of the electrodes are insulated except at the tips. CONSTITUTION:Two electrode rods 17 and 18 are suspended from an insulating bushing 16 at the tip of an arm 15 located on a base 12 in such a manner that the electrode 17 is set slightly shorter than the electrode 18 on the center side of a mold 10. With a switch on, the base 12 is magnetically fixed on the upper wall 11 of the mold, with the start of casting, the surface of a molten metal rises to contact the tips of the electrodes 18 and 17 sequentially. The molten metal surface level and the rising speed thereof are detected from the time of the contacts. As the electrodes are covered with an insulation layer 19 on the circumferential surface except at the tips, no erroneous detection of the molten metal surface level will not occur even when the molten metal contacts upper part of the electrodes by a sprash. Besides, quick removal of the electrodes with the switch off enables the avoidance of troubles due to the attaching of a base metal.
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