Device for the manufacture of a double-walled plastic pipe comprises a corrugated outer tube and a smooth inner pipe

摘要

An improvement in an apparatus for forming an outer corrugated tube wherein the corrugations of said tube abut an inner tube within said corrugated tube, said apparatus comprising means for forming an outer corrugated tube about a dye, means for forming said inner tube about a central mandrel within said corrugated tube, the improvement comprising means for urging an inner tube against the corrugations of said outer corrugated tube, said means comprising a presser floating mounted within said inner tube in facing relationship to said inner tube and bearing outward towards said inner tube.