Induction heating and melting systems having improved induction coils

摘要

Improved electric induction heating apparatus wherein the coil has two or more windings of special low loss conductor with such windings electrically connected in parallel. The two or more windings can be wound simultaneously one on top of the other and/or disposed radially one outside of the other. The coil windings embedded in a rigid set resinous material thus providing a rigid cylindrical unit. At least one of the coil windings has the low loss conductor around a tube the latter providing a fluid flow path for circulatig cooling fluid therethrough by at least one of current balancing transformers, transposition of the windings, and appropriately choosing the number of turns of each coil layer. A split ring bus can be used at the ends of the coils to connect the windings in parallel and laminated steel yokes can be disposed about the coil. There is also disclosed an improved inductive coil assembly for electric inductive heating apparatus comprising a cylindrical winding embedded in a temperature resistant non-magnetic material such as glass fibre reinforced resin and a heat sink rigid unit removably disposed within such coil unit. The heat sink unit comprises conduit means embedded in a temperature resistant material and providing a fluid flow passage for circulating a cooling fluid therethrough. The heat sink is removably inserted in the inductive coil unit. The helical winding is wound from a liquid cooled low loss conductor.