| 摘要 |
A heating wire (6) is inserted in turns, which are at a distance (7) from the adjacent turns and whose ends are connected to contacts (8) for connection to a welding apparatus, in a collar body (4), in the vicinity of the inner wall (5). The heating wire has a thermal coefficient of expansion of less than 10 x 10<-6>. In order to produce welded connections, the collar (3) is pushed onto pipe connecting stubs (1, 2) and heat is produced in the heating wire (6), as a result of which heat the collar body (4) and the pipe connecting stubs (1, 2) are partially softened. Since the collar body (4) has a shrinkage reserve which is released when the material is softened, it rests against the connecting stubs (1, 2), cancelling out an assembly gap (10). As a result of the low thermal coefficient of expansion, winding shorts or other deformations of the heating wire (6) before the thermoplastic material softens are prevented. <IMAGE> |
