INDUCTION HEATING COIL FOR HEATING INNER CIRCUMFERENTIAL SURFACE OF TUBE BODY

摘要

PROBLEM TO BE SOLVED: To provide a heating coil capable of uniform heating in a simple and safe manner, by disposing a plurality of longitudinally extended bar-like cores of layered silicon steel sheets on the side of an inner diameter of a wire-wound coil having an outer diameter forming a fixed gap bordering an inner surface of a heated tube body. SOLUTION: A plurality of cores 20 disposed on the side of an inner surface of a wire-wound coil 12 are formed into the shape of a square bar by winding an insulator 22 around the outer circumference of layered silicon steel sheets 21 of an elongate rectangular shape. The plurality of cores 20 are circumferentially disposed between an inner-diameter surface of the wire-wound coil 12 and the outer diameter of a center lead tube 15, and fixed by an insulating tube 16 mounted on the outer diameter of the lead tube 15 and by an insulating filler 17. Both end parts of the wire-wound coil 12 are caused to project by fixed lengths from both ends of a heated tube body W while a fixed gap is formed between the outer diameter of the wire-wound coil 12 and an inner circumferential surface of the heated tube body W, and the heated tube body W is heated from the inner surface side thereof. This induction heating coil 11 is capable of uniform heating while standing still and efficiently heats the heated tube body W.