Corrugated extruded pipe production machine has an internal mandrel supported by electromagnetic force to retain profiled pipe on a set axis when profile dies separate

摘要

In an extrusion machine, two opposing sets of dies(112) move continuously around closed paths and create a forming channel(110) between them in which an extruded pipe is profiled. A force field generator(410,420) outside the point at which the dies open applies electromagnetic force on a mandrel(300) inside the profiled pipe(200). In an extrusion machine, two opposing sets of dies(112) move continuously around closed paths and create a forming channel(110) between them in which an extruded pipe is profiled. A force field generator(410,420) outside the point at which the dies open applies electromagnetic force on a mandrel(300) inside the profiled pipe(200). The force ensures the mandrel is held so that it slides along the inner pipe wall or makes contact with this when it deviates from a prescribed axis(210). Independent claims are made for: (a) use of a suspended internal mandrel(300) held by magnetic force for forming extruded profiles, in particular corrugated pipe(200); (b) a process for production of a profiled extruded pipe in which: (i) split dies(112) are pressed onto the outer surface of an extruded pipe and move with the latter along a forming zone to form the external profile; (ii) the pipe is cooled and a mandrel is introduced into the pipe; and (iii) the dies separate from the pipe which is then held on its axis by the magnetically suspended mandrel.