Bending of thermoplastic tubes

摘要

A method and apparatus for bending thermoplastic tube in which a pre-heated region of the tube is conformed to a required bend configuration while supported internally and externally to prevent the tube wall collapsing. The external support is provided by relatively movable formers which enclose a section of the tube at the point where the bending force is applied and this enclosed section moves progressively along the heated region as the bend is developed by the relative movement of the formers. The internal support is provided by fluid pressure higher than atmospheric pressure within the tube during the forming operation. Multiple bends can be formed sequentially and/or siitultateously.