1991 Volume 77 Issue 9 Pages 1442-1449
In order to improve the energy efficiency of a segmented conductive crucible, experimental measuerments and theoretical analysis have been conducted.
When the segments of the crucible are electrically shorted at the bottom, the magnetic filed intensity in the crucible is decreased by decreasing the longitudinal distance between the coil and the short circuit part of the crucible. When the segments of the crucible are insulated each other, the magnetic intensity is scarcely influenced by changing the relative position of the coil and the crucible. The effect of crucible length on magnetic field distribution is not clearly appeared in the both cases in which the segments of the crucible are electrically shorted and insulated. These experimental results are explained by a mathematical model. A new induction heating process in which segments are not cooled unlike the cold crucible has been proposed and named a hot crucible. From the measurments of heating rate of the charges under both the cold crucible and the hot crucible conditions, the heating under the latter was found to be about 1.72.5 times faster than that under the cold crucible condition.
