| 主权项 |
1. An apparatus for the continuous production of a twin wall pipe consisting in a conveying direction of a smooth internal pipe and an external pipe welded thereto and provided with corrugations, and a first centre longitudinal axis,
wherein mold block halves provided with annular mould recesses, supplementing one another in pairs in each case on a molding section to form a mould with a second centre longitudinal axis, are arranged in a circuit and guided in a conveying direction, wherein the mould recesses are connected to partial vacuum channels formed in the mold block halves, wherein a pipe head of at least one extruder is arranged upstream of the molding section, wherein the pipe head is provided with an external nozzle for the extrusion of an external hose and, downstream in the conveying direction, with an internal nozzle for the extrusion of an internal hose and, at its end located downstream in the conveying direction, with a calibrating mandrel, wherein at least one support air channel opens out of the pipe head between the external nozzle and the internal nozzle,wherein the support air channel is configured as a support air and venting channel, which is constantly open to the atmosphere, is annular-cylindrical at least adjacent to the region between the internal nozzle and the external nozzle and is concentric with respect to the second centre longitudinal axis. |
