Patent ID: 6635856
Filing Date: 2003-10-21
Classification: H05B

Abstract:
Apparatus for sequentially induction heating a plurality of billets, the apparatus comprising:a plurality of induction coils, the number of the plurality of induction coils equal to the number of the plurality of billets, each of the plurality of billets inserted into an individual one of the plurality of induction coils, each of the plurality of billets substantially surrounded along its axial length by the individual one of the plurality of induction coils; an at least one ac power supply providing ac current to each of the plurality of induction coils; and a means for individually connecting each one of the plurality of induction coils sequentially to the at least one ac power supply for a variable time period in each one of a plurality of power cycles, the number of the plurality of power cycles equal to the number of the plurality of induction coils, the variable time period in each successive one of the plurality of power cycles for each one of the plurality of billets being a shorter time period than the time period in the prior power cycle, the variable time periods for connecting each of the plurality of induction coils over the plurality of power cycles being equal in time, and the variable time periods for connecting each of the plurality of induction coils in a power cycle being different for each one of the plurality of induction coils, whereby each of the plurality of billets is sequentially induction heated after completion of the plurality of power cycles for each of the plurality of billets.