PRODUCTION OF FOAMED RESIN PIPE AND DEVICE FOR HELICALLY GROOVING OUTER PERIPHERAL SURFACE OF RESIN PIPE

摘要

PURPOSE:To obtain a method for producing a foamed resin pipe hardly generating a buckling phenomenon and having superior heat insulating properties and to obtain a device for helically grooving an outer peripheral surface of the resin pipe. CONSTITUTION:A foamable resin is extruded in a pipe form through a resin path 13 between a die 1 and a nipple 2. The top of the nipple 2 is projected from the top surface of the die 1. On this projected part 2a, an outer peripheral surface of a resin pipe Y is bitten by a roll cutter 8. The roll cutter 8 is rotated and revolved around the resin pipe Y to helically groove the outer peripheral surface of the resin pipe Y. After that, the foamable resin is foamed. In this manner, a foamed resin pipe having a helical groove on its outer peripheral surface is obtained.