Patent ID: 8713971

Claim:
A method for melting glass comprising: providing a current conducting melting vessel within which glass can be melted; the melting vessel includes an inlet formed by a neck region and at least one outlet arranged respectively for receiving glass frit and draining the contents of the vessel to a location below the vessel during a draining operation providing at least two induction heating coils at selected locations proximate to the melting vessel and a plurality of power supply circuits each being associated with a respective one of the heating coils and being arranged for selectively supplying power to the respective coil to thereby energise that respective coil; locating glass forming material within the vessel selectively supplying power to the heating coils to thereby selectively energise the coils and melt the glass forming material; and preventing or permitting a mutual induction of current in at least one of the heating coil adjacent to an energised heating coil by selecting an on or off status of a switching element in a respective one of the power supply circuits associated with the adjacent heating coil, wherein the switching element is switchable between the off status in which mutual inductance of current is prevented in the adjacent heating coil and the on status in which mutual inductance of current is permitted in the adjacent heating coil, and wherein the power supply circuitry associated with each heating coil includes: a first portion comprising; a supply leg and a return leg connected to a power supply; and a transformer element connected between the supply leg and the return leg; and a second portion connected to a supply node in the supply leg and a return node in the return leg, the second portion comprising the heating coil and the switching element.