| 摘要 |
PURPOSE:To reduce the usage of electric power by disposing electrodes in conact with an electric welded pipe on the upper stream and down stream sides respectively in the conveying direction of the electric welded pipe of an electromagnetic inductor of a post annealing device and connecting both electrodes by means of conductors. CONSTITUTION:Two electrodes 20, 30 for contacting a steel pipe SP and a conductor 40 short circuiting the electrodes 20, 30 are provided to an electromagnetic inductor 10 consisting of an iron core 11 of a rectangular parallelepiped shape and a conductive part 12 disposed on the outside circumference theeof. The electrodes 20, 30 contact with the steel pipe SP at the upper and down stream side ends of the inductor 10, that is, in the positions slightly deviating to the upper and down stream sides from the parts of outer conductors 12b, 12c covering the upper and down stream end faces of the iron core 11. Since the electric current flowing in the conductor 10 is in the direction reverse from the current of the outer conductors 12b, 12c, the impedance of the conductor 40 is decreased by the high frequency proximity effect of the return current thereof. Thereby, the wasteful resistance loss such as flow of curent to the steel pipe SP and flow of leakage to ground current is prevented. |
