1994 Volume 80 Issue 3 Pages 195-200
A new method of melting and holding of a material with low thermal and electrical conductivities is proposed toovercome the problems of long heating period and localized overheat in a charge. In this method, a water cooled induction coil is directly used as a crucible, and the elements heated by a high frequency magnetic field are submerged into the charge. Experiments have been conducted on glass under various operating conditions, i.e. the coil current, the frequency and the radius of the heating elements. A mathematical model is developed to calculate the process variables such as the heat generation rates in the coil and the heating elements, and the temperature distribution in the charge. The calculated process variables are compared with the observed ones. The considerably good agreement between the theoretical and experimental results indicates the validity of the model. The heat generation rate in the heating elements is determined by the ratio of the radius of the heating element to the electromagnetic penetration depth and has the maximum value at the ratio of 1.8.