Patent ID: 7214051

Claim:
A device for manufacturing a double-walled thermoplastic pipe with a connecting sleeve comprising: a molding tunnel formed by a succession of molds guided on a path, at least a first portion of said molding tunnel having a corrugated molding wall, and at least a second portion of the molding tunnel having a sleeve recess corresponding to said connecting sleeve, an extrusion device provided with an extrusion head, said extrusion head having a first die for extruding a first flexible tube into said molding tunnel, and a second die that is arranged downstream in direction of movement of said molds within said molding tunnel, for extruding a second flexible tube, a first gas channel arranged between said two dies, and a second gas channel that opens out downstream of said second die in the direction of movement of said molds of said molding tunnel, a compressed-gas feed, a first compressed-gas control device that is connected to said compressed-gas feed and said first gas channel for generating a pressure p 1 or a pressure p 2 in a space formed between said first flexible tube and said second flexible tube by compressed air emerging from said first gas channel, said first compressed-gas control device comprising a pressure controller, a second compressed-gas control device connected to said compressed-gas feed and said second gas channel for generating a pressure p 3 on an inner side of said second flexible tube by compressed gas emerging from said second gas channel, said pressure p 3 lying above atmospheric pressure, and a control device for controlling the first and second compressed-gas control devices, said first compressed-gas control device being connected to said first gas channel via a compressed-gas line that is connected to a compressed-gas reservoir for gas exchange therewith.