PRODUCING DOUBLE-WALLED HELICALLY WOUND THERMOPLASTIC PIPE WITH A CORRUGATED WALL

摘要

A system is disclosed for the production of double-walled helically wound thermoplastic pipe. The apparatus includes an endless former (10) of the axially advancing and rotating type for forming a band of thermoplastic material (24) into a corrugated outer wall (26). An internal extruding device (28) extends along the core of the former and extrudes a second band (34) of thermoplastic material onto the interior of the outer wall. A cold shoe (36) presses the inner wall against the outer wall to form a smooth inner wall (42) of the double-walled pipe. It is also possible to provide for the insertion of a reinforcing profile in the corrugations of the outer wall.