PRODUCTION OF SYNTHETIC RESIN COATED METAL PIPE

摘要

PURPOSE:To continuously, uniformly and efficiently heat a metal pipe over the whole thereof without generating temp. difference in the circumferential direction of the metal pipe by heating the metal pipe while allowing the same to tumble and rotate on a conveyor. CONSTITUTION:Metal pipes 1 each having a synthetic resin tube 2 inserted therein are parallelly arranged on a conveyor 11 to be moved at a constant speed in the direction shown by an arrow (a) crossing the axial direction of the metal pipes at a right angle. The coil 13 having an oval shape of an electromagnetic induction heater 12 is arranged obliquely with respect to the moving direction (a) of the metal pipes 1 so as to surround the metal pipes 1 and the conveyor 11. That is, one loop end 13a of the coil 13 is positioned on the upstream side of the moving direction of the metal pipes 1 and the other loop end 13b thereof is positioned on the downstream side of the moving direction of the metal pipes 1.