Inductive connecting of plastic objects by a coil arrangement with multiple individual coils

A method for thermally connecting a pipe, which has a first plastic material, to a bushing, which has a second plastic material, and which surrounds at least a section of the pipe, wherein an inductively heatable heating means is located between the pipe and the bushing and/or integrated in the pipe and/or the bushing, the method comprising:

• laying alongside a heating device to the bushing from an outside, the heating device including a coil arrangement, which is excitable by a generator, and which has a first coil, which has at least one complete winding within a first cross-sectional area, and a second coil, which is electrically coupled to the first coil, and which has at least one complete winding within a second cross-sectional area, wherein the first cross-sectional area is different from the second cross-sectional area;
• laying a tensioning device alongside an outward surface of the bushing, such that the bushing is subjected to a pressure that is constant along an outer circumference of the bushing;
• exciting the coil arrangement;
• and
• removing the heating device from the bushing.