| 摘要 |
A welding sleeve useable for connecting of pipes formed from thermoplastic material, is formed from a tubular body of thermoplastic material and a coil disposed on its inside surface. The coil has a resistance wire encased with thermoplastic material. The windings of the coil (4) are bonded into a compact coil which is inserted into the heated tubular body while it is simultaneously widened. As the result of a partial contraction of the tubular body also of the coil a firm connection develops between the oil and the body. Furthermore, the tubular body has a frozen-in, latent, radial contraction strain as a result of the widening, which during heating during the welding process, eliminates the radial play between coil and the pipes and produces a welding pressure. |
