| 摘要 |
The coil has a spiral wound profile strip (1) welded along a spiral contact area formed by adjacent profile strip sections under formation of a welding seam (2). The profile strip is arranged with a functional layer in an area of the welding seam, where melting point and melting range of a material of the functional layer are lower than melting point and melting range of a material of the profile strip. The profile strip and the functional layer are made of polyolefin i.e. polyethylene. The functional layer is radially aligned to a cylindrical cavity (3) in a welded condition. |
