Twin-wall tube bending process - by inserting container-shaped FRP packing piece having axial slits into annular gap between inner and outer tubes

摘要

Processes for bending twin-walled tubes (20) involve the insertion of a mandrel (11) into the inner tube (21) and filling the gap (22) between the tubes (21,23) with a material such as sand. In the new process a container-shaped packing device (30) with axial slits, is inserted into the annular gap between the tubes (21,23) and bends with the tubes. The container (30) is mfd. in a fibre-reinforced plastic in the form of axial fingers held at onem end (32). The fibres may be of glass, carbon or aramid. USE/ADVANTAGE - The process and device provide a simpler and faster method of bending double-walled tube without the occurence of folding.