| 摘要 |
<p>The invention concerns a method of automatically welding heater coil fittings substantially made of plastics. According to the invention, data concerning the fitting are automatically read in particular from a data carrier of the fitting. The welding power supplied to the heater coil is controlled on the basis of these data and taking account of the ambient temperature. In order that welding can be carried out reliably even at low ambient temperature and with high air humidity without the assembly area being heated, when the ambient temperature is below a predetermined value a preheating and dehumidifying step is carried out before the step in which the welding power (PSchw) is fed to the heater coil. During the preheating and dehumidifying step, the heater coil is acted upon with preheating power (PVorw) which is less than the welding power (PSchw) for a predetermined preheating and dehumidifying period (t1 - t2) until the weld surfaces of the fitting (1) and of an adjacent pipe and the air between the weld surfaces have been preheated to a temperature which is higher than ambient temperature and at which the plastics has not yet plasticized.</p> |
