Patent ID: 6251332
Filing Date: 2001-06-26
Classification: B29C,B29D,B29K,B29L,F02M,F05C,F16L

Abstract:
A method for manufacturing a multi-layered plastic pipe, comprising:forming a hollow plastic core having a desired shape by blow-molding;bringing a plurality of mold segments into a semi-mating condition with a gap existing between any two adjacent mold segments with said hollow plastic core positioned inside a mold cavity defined by said plurality of mold segments, said gap allowing any gas present in said mold cavity to escape therethrough to the exterior but not a molten plastic material;supplying a molten plastic material into said mold cavity while said plurality of mold segments are in said semi-mating condition; andbringing said plurality of mold segments into a final mating condition to thereby form an outer layer integrally on an outer surface of said hollow plastic core from said molten plastic material.