EXTRUSION COATING APPARATUS OF RESIN COATED METAL PIPE AND METHOD FOR FORMING RESIN COATING LAYER ON METAL PIPE

摘要

PPROBLEM TO BE SOLVED: To provide an extrusion coating apparatus of a resin coated metal pipe for uniformizing the wall thickness of a coating layer due to extrusion coating and improving the adhesion thereof at the same time, and a method for forming a resin coating layer on a metal pipe. PSOLUTION: The extrusion coating apparatus of the resin coated metal pipe is composed of a guide core which is constituted so that the leading end part thereof is formed as a knife-like pointed end edge and a guide hole for the metal pipe moved to an axial center part is provided in a piercing state and has an outer peripheral surface expanded rearward from the pointed end edge, and a nozzle means, which is constituted so that the inner peripheral surface of the axial center thereof is coaxially providerd to a casing up to the nozzle orifice provided to the leading end of the nozzle means so as to hold a conical flow channel gap with the inclined surface of the guide core, and characterized in that the end edge part of the nozzle orifice almost coincides with the knife-like pointed end edge part of the guide core and is positioned in close vicinity to the outer peripheral surface of the metal pipe moved through the guide core. In the method for forming the resin coating layer on the metal pipe, the molten resin issued from the nozzle orifice is applied to the outer peripheral surface of the axially moved metal pipe as rapidly as possible. PCOPYRIGHT: (C)2005,JPO&NCIPI