Abstract: An induction heating workcoil has a ferrite core on which are wound multiple layers of an electrically conductive material. To cool the winding, solid thermal conductors are inserted between the multiple layers of the winding to provide a thermal interface with the multiple layers. The workcoil can also have a hollow tube that is wound on the outside of the winding with the tube having a liquid circulating through it to cool the winding. The core can have a cross-shaped top and an I-shaped leg with the multiple layers of the winding wound on the leg of the core. The solid thermal conductors can extend above the height of the windings so that the heat to be dissipated is transferred to the upper portion of the workcoil. The multiple layers of the winding are tightly wound on the solid thermal conductors to maximize the thermal interface.

Abstract: One embodiment of the heated roll apparatus uses an optimized roll whose surface layer is composed of a material responsive to being heated, particularly by external magnetic induction, and the depth of which, as well as the construction of the rest of the roll, uses one or more other materials whose properties are optimized with respect to maximizing the roll's rate of temperature change, minimizing energy usage, and performing the intended application. A thin outer ferrous layer over top of a thicker ceramic, insulating layer may be used. The roll may also include an outer layer that is responsive to heating, particularly by magnetic induction, and one or more inner layers of different material(s) chosen to increase the roll's rate of temperature change and reduce energy usage, but which are further selected to promote rapid lateral heat conduction to reduce lateral temperature variations. This roll could include a thin outer ferrous layer over top of a thicker aluminum core.

Abstract: An induction heating device or work coil for heating electroconductive material to a desired temperature that can be used on a roll or cylinder of any diameter. The work coil has an open core of ferrite material shaped in a U. Wire is wound around the opposing legs of the U so that on excitation one leg becomes the N pole and the other leg becomes the S pole and the polarity alternates as the polarity of the excitation current alternates. A substantially thin rectangular flat layer of ferrite can be attached to ends of each pole piece. Each layer of ferrite has having a length sufficient to cover bottom end of each leg and a width in the direction of an axis perpendicular to the face of the U that corresponds to the width of the desired control heating effect.

Abstract: There is disclosed an induction heating device or work coil for heating electroconductive material to a desired temperature. The work coil can be used on a roll or cylinder of any diameter. The work coil has an open core of ferrite material shaped in a U. Wire is wound around the opposing legs of the U so that on excitation one leg becomes the N pole and the other leg becomes the S pole and the polarity alternates as the polarity of the excitation current alternates. A substantially thin rectangular flat layer of ferrite can be attached to ends of each pole piece. Each layer of ferrite has having a length sufficient to cover bottom end of each leg and a width in the direction of an axis perpendicular to the face of the U that corresponds to the width of the desired control heating effect.