Abstract: The side seam of a can is coated and heated inductively by passing it through a medium frequency, oscillating magnetic field generated by an induction coil wound around a core. The core is shaped and oriented so as to have two magnetically opposite poles direct magnetic flux in a concentrated manner from the coil into the side seams of cans traveling along a path of travel. The cores are constructed using individual laminations of high frequency core material, each less than about 0.006 inches thick, individually insulated from each other and bound together to form a U- or E-shaped core directing flux toward the workpiece. The induction coil is constructed using a form of Litz wire and the coil and core are air-cooled. In one embodiment, the core has a plurality of pole pieces each directed toward the path of travel. The induction coil is wound on the core such that sequential ones of the pole pieces along the path of travel have alternatingly magnetically opposite polarities.

Abstract: A method and apparatus for 360.degree. induction heating of a can body to cure or partially cure a protective coating applied thereto. The can bodies are inductively heated by placing them in a medium frequency, oscillating magnetic field generated by a multiple turn induction coil helically wound around the transport path of the can body. By using a medium-frequency field and by centering the can bodies with respect to the induction coil, the can bodies may be evenly and uniformly heated around 360.degree. of their circumference.