Procedure and tools for bending pipes lying inside each other with air gap

摘要

Procedure and tools for bending pipes lying inside each other, with air gap, wherein the pipes 2 and 3 connected at one end are bent to the required shape in one or more stages. For the bending operation, a conventional CNC- controlled bending machine is used, equipped with supplementary software for handling the double piping 1. In the inner pipe 3 there is a ball mandrel 9, while between the pipes 2 and 3 is a spring mandrel 14 consisting of a spring 16 on whose outer surfaces 17 and 18 ribs or wires are fitted. <IMAGE>