METHOD AND INSTALLATION FOR THE PRODUCTION OF A MULTILAYER PIPE OF THERMOPLASTIC MATERIAL, IN PARTICULAR POLYOLEFINE

摘要

For the production of a multilayer pipe of thermoplastic material, in particular polyolefine, an extrusion equipment is provided, extruding at least one tube in a direction of production. A calibrating arrangement for forming a pipe of externally profiled shape is provided downstream of the extrusion equipment. The calibrating arrangement is followed by a preheater for heating to welding temperature the outer surfaces of the externally profiled shape. Furthermore, a coextruding head is provided, having an extruder for coextruding a tube around the pipe, the coextruding head having a partial vacuum connecting line for the tube and the outer surfaces to be welded together under the difference pressure between ambient pressure and partial vacuum.