| 摘要 |
PURPOSE:To instantly detect the leakage of a melt from a crucible by impressing a constant voltage between a crucible holder and a seed crystal hanger, and detecting the changes in the electric current flowing between the holder and the hanger or in the electric resistance. CONSTITUTION:A constant voltage from a detecting electric power source 14 is impressed between a holding shaft 2 constituting the holder for a quartz crucible 4 and the shaft 7 for lifting the seed crystal 8. The change in the current following between the holding shaft 2 and the lifting shaft 7 or in the resistance are continuously detected by a current measuring device 15, and the detection signal is inputted to a controller 16. The inputted current value is compared with the set reference current value, and an alarm 17 is actuated when the detected detected current value exceeds the reference current value. The breaker 13 or a heater power source 12 is simultaneously actuated. The detection signal for the leakage of a melt from the crystal pulling up furnace can be surely obtained by this mechanism by setting the reference current value to an appropriate value.
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