Method and apparatus for the continuous manufacturing of a composite pipe having a substantially smooth external wall portion

摘要

For the continuous manufacturing of a composite pipe comprising a smooth inner pipe (45) and an outer pipe (42) which is provided with transverse grooves (24) and is welded to the said inner pipe, having a substantially smooth external portion (spigot end 46), an outer tube (41) is extruded and an inner tube (43) is extruded into the said outer tube. During manufacturing of the substantially smooth external portion (spigot end 46), the outer wall (52) of the latter is pressure-relieved by compensation chambers (49).