Method of shaping of a thermoplastic pipe into a curve, used for transport of e.g. fuel in vehicles, comprises heating the smooth pipe to its softening point and inserting it into a mold with a heated stamp to impose the curved shape

摘要

Method of shaping a thermoplastic pipe into a curve comprises (a) locally heating the pipe to its softening point; (b) fitting a mold (21a, 21b) which includes a stamp around the heated zone; (c) developing a pressure difference between the mold and the interior of the pipe in order to force the pipe against the stamp (24) and impose a curve on the smooth pipe. Method of shaping a thermoplastic pipe into a curve comprises: (a) locally heating the pipe to its softening point; (b) fitting a mold (21a, 21b) around the heated zone. The said mold includes a stamp (24) held at a controlled temperature which is lower than the softening point of the pipe material; (c) developing a pressure difference between the mold and the interior of the pipe, with the higher pressure in the pipe, to force the pipe against the stamp (24) and impose a curve on the smooth pipe; (d) cooling the pipe; and (e) removing pipe from mold. The pressure difference is developed by evacuation within the mold or an overpressure within the pipe. An Independent claim is also included for an apparatus to bend thermoplastic pipes comprising a heater (20a,20b) to heat and soften the pipe at the bending zone and a manipulation mechanism for the heated sections at the heating zone.