CORROSION RESISTING CORE FOR INTERNAL SURFACE OF TUBE WELD

摘要

PURPOSE:To perform a corrosion resisting treatment with easy, certainty and inexpen siveness irrespective of the size of a tube by sequentially opening rings to expand a coil expandable in the radial direction, and expanding a corrosion resisting cylinder coated with adhesive in the radial direction. CONSTITUTION:A corrosion resisting cylinder 11 is formed of a flexible material so as to be radially expanded by the force from the inner surface side, and is previously coated on the outer surface thereof with adhesive. A coil 12 wound in a cylinder- shape is disposed within the corrosion resisting cylinder 11, and is formed by winding of a material 12a having a corrosion resistance and a high elasticity in spiral to be radially expandable. Further, a plurality of diameter contracting ring 13 are wound around the outer periphery of the coil 12 at a specified interval. By such a opening or closing the ring, the coil 12 is expanded or contracted. Thus, when a fixing line 14 is pulled off at a specified speed after termination of welding, the diameter contracting ring 13 is sequentially opened from the end, and thereby the coil 12 is sequentially expanded from the end. Therefore, it is possible to sequentially bring the corrosion resisting cylinder 11 in close-contact with the inner surface 51 of the tube 50 from the end without staying of air, and hence to certainly perform the corrosion resisting treatment for a weld 52.