Bending method for a pipe made from thermoplastic material, using a bending core with a flexible middle section inserted into the pipe

摘要

Prior to heating the pipe (1), the core (2) is introduced into the region of the pipe being bent and the core end caps are forced towards each other by axial compression, resulting in a radial expansion of the middle section (3). A method for bending a pipe made from synthetic (preferably biaxially oriented) thermoplastic material, comprises heating part of the pipe to a given temperature, introducing a bending core into the region of the pipe to be bent, bending the pipe in this region, cooling the pipe and removing the core. The bending core comprises an elastically bendable middle section and two rigid end caps (4, 5) joined together by a connector piece (6) extending through a channel (7) in the middle section. Prior to heating the pipe, the core is introduced into the bending region and the end caps are forced towards each other by axial compression, resulting in a radial expansion of the middle section, preferably so that it is urged against the inside of the pipe. Independent claims are also included for (a) a bending core used in this method, where the middle section comprises a number of coaxial, bendable hose sections, (b) a bending core construction used to form more than one bend in a synthetic thermoplastic material pipe, and (c) a bending core used in this method, where at least one end cap has a clamping means for securing it to the connector piece when the core is introduced into the pipe.