Patent ID: 6537484
Filing Date: 2003-03-25
Classification: B29C,B29D,B29K,B29L,F02M,F05C,F16L

Abstract:
A method for manufacturing a multi-layered plastic pipe, comprising the steps of:forming a tubular hollow plastic core having a desired shape by blow-molding; providing at least one spacer member having a desired shape on said tubular hollow plastic core; placing said tubular hollow plastic core in a mold cavity with said at least one spacer member having a desired shape interposed between a wall surface of said mold cavity and an outer peripheral surface of said tubular hollow plastic core to maintain a gap between said wall surface of said mold cavity and said outer peripheral surface of said tubular hollow plastic core; supplying a molten plastic material into said mold cavity while keeping the shape of said at least one spacer member having a desired shape substantially intact; and applying a compression force to said molten plastic material inside said mold cavity to thereby form in said gap an outer layer from said molten plastic material on the outer peripheral surface of said tubular hollow plastic core integrally therewith and around said at least one spacer member having a desired shape.