Patent ID: 8884199
Filing Date: 2014-11-11
Classification: F27D,H05B,Y02P

Abstract:
1. A method of heating and melting a material in a vessel at least partially comprising a susceptor by supplying an alternating current to at least two induction coils surrounding different sections of the vessel, the method comprising the steps of: placing a charge of the material in the vessel; supplying the alternating current from a separate power source to each of the at least two induction coils, an output voltage of each of the separate power sources operating with a phase synchronization; and varying a magnitude of electric power to each of the at least two induction coils by an independent pulse width control of the output voltage of each of the separate power sources operating with the phase synchronization to heat and melt the material by initially supplying a ratio of at least 2 to 1 of a total power supplied to a bottom one of the at least two induction coils located nearest the bottom of the vessel relative to a top one of the at least two induction coils located nearest the top of the vessel, and decreasing the 2 to 1 ratio of the total power as the material transitions from a solid state to a molten state.