Abstract: A method and system for controlling the heating of a product in an electromagnetic induction heating installation having a pair of essentially identical inductors placed on either side of the product with the poles of one of the inductors of the pair facing the poles of the other inductor. The average heating power electromagnetically induced in a moving or stationary, flat, conducting product positioned without contact by electromagnetic forces correlatively induced by the electromagnetic heating field is controlled by effecting a sequence of inversions of the instantaneous polarity of the poles of one of the inductors with respect to the instantaneous polarity of the corresponding poles of the other inductor. The ratio of the durations during which the polarities are on the one hand opposite and on the other identical determines the average value desired of the heating power induced, and the position of the product remaining practically unchanged by said inversions.

Abstract: A process and apparatus for inductive heating of flat, thin, conductive, nonmagnetic products of variable dimensions. A plurality of currents are inductively generated in the product in such a way that elementary current arrays are formed in the product in both the longitudinal and lateral directions. Current arrays of local heating heterogeneity, each comprising at least one of the elementary current arrays, are defined, and the intensities of the inductively generated current in the arrays of local heating heterogeneity are controlled as a function of the volume of the array of local heating heterogeneity with which they are associated, so that the average value of power dissipated per unit volume in each array of local heating heterogeneity is approximately the same as for all other arrays. The apparatus specifically includes an inductor with individually controllable coils (poles) arranged to extend longitudinally and laterally over the area of the product to be heated.

Abstract: Magnetic induction heating apparatus for flat, rectangular metal products travelling in the direction of their longitudinal axis, comprising at least one inductor mounted so as to rotate about an axis perpendicular to a wide face of the metal product and comprising at least two magnetic poles having polar surfaces sweeping out an annular area as the inductor rotates about the perpendicular axis. In order to effectuate the homogeneous heating of the metal product in the transverse direction, the polar surface of each magnetic pole has the shape of a curvilinear triangle with a truncated apex directed toward the axis of rotation of the inductor, two concave sides which are symmetric with respect to a straight line passing through the truncated apex and perpendicular to the axis of rotation, and a convex side of circular arc centered about the axis of rotation having a radius of curvature essentially equal to the external radius of the annular area sweep by the polar surfaces of the magnetic poles.

Abstract: Continuously moving, elongated, thin work products are subjected to homogeneous electromagnetic inductive heating in the transverse direction. The heating is achieved by an induction heating apparatus having a rotating inductor with a plurality of magnetic poles and an adjustable yoke. The inductor is rotatable about an axis and the work product is guided by a rotatable support in a loop path coaxial with the axis. The yoke includes at least two elements that are movable relative to one another to vary gap between the inductor and the yoke to thereby generate a traverse profile of the resultant moving magnetic field across the width of the work product. The magnetic field is uniform in the center zone of the work product, then at either edge of the work product, first increases and then subsequently decreases to a value below the uniform field with increasing distance away from the center zone.