COLD CRUCIBLE AND METHOD FOR MONITORING TEMPERATURE AT FURNACE WALL

摘要

PROBLEM TO BE SOLVED: To provide a cold crucible and a method for monitoring temperature at a furnace wall in which a local melting of the furnace wall can be detected in advance in a precise manner. SOLUTION: There is provided a cylindrical furnace wall 3 comprised of a plurality of conductive segments 4 divided by some slits and having a cold water feeding passage 5 in it. An electrical applying coil 10 is installed at an outer circumference of the furnace wall. This cold crucible 1 has no furnace bottom segment. A temperature sensor 14 for use in measuring a temperature of the furnace wall is inserted from an outer part of the furnace wall into a void formed in the segment. In the case that an output signal from the temperature sensor is out of a value set as a monitoring limit value, at least one of occurrence of alarm and a shielding of high frequency current supplied to the electrical applying coil is carried out.