| 摘要 |
PROBLEM TO BE SOLVED: To detect simply and accurately molten surface position and dipping depth. SOLUTION: In this detecting method, a cylindrical cooling body 21 and a rotating shaft 25 are constituted of graphite sintered body and made conductor. A crucible 22 is constituted of graphite and made conductor. The crucible 22 is electrically insulated from a crucible base 26 by using an alumina plate 27. Therefore a closed circuit of the cooling body 21, fused silicon 23, the crucible 22, a heat resistant wiring 29, a resistance meter 30, a wiring 28 and the rotating shaft 25 is formed. Large change of a resistance value when the cooling body 21 comes into contact with the fused silicon 23 is detected with the resistance meter 30, and the molten surface position of the fused silicon 23 is precisely detected. The logarithmic value of the resistance value with the resistance meter 30 is almost inversely proportional to the logarithmic value of the dipping depth. The amount of change of resistance value after the cooling body 21 reaches the molten surface position is measured, and the dipping depth of the cooling body 21 is precisely detected.
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