| 摘要 |
<p>A welded pipe fitting is made from thermoplastic, weldable material, as also are the two pipes themselves (20). The fitting (11) has contacts (14) for electrical power connections and between them, an spiral heating wire (15) embedded in a sleeve. The position of this coil is such that it allows the material in the contact zones to melt. A welding indicator (16) integrated with the housing of the fitting shows the condition of the welded joint. There are two contact zones for the heater. One stretches from the edge of each pipe back towards the welding indicator but not up to it, where the inner sleeve of the fitting is thin. The other zone lies under the indicator, where the sleeve is thick.</p> |
