Winding a glass tube into a double coil

摘要

To produce a glass tube with a double twist, the glass tube is held in a preliminary stage at least close to the shape of the twisting and the pitch of the twisted spiral. Also claimed is an appts. with a winding mandrel (2) matching the inner dia. of the double spiral (3) and two cylinders (5) displaced by 180 deg as the counter profile (4), operated against the direction of the winding mandrel. The counter profile (4) gives a mirror image structure matching the shape and pitch of the double spiral (3) to be produced.