| 摘要 |
The invention relates to electrofusion fittings. Hitherto, electrical leads (13) to electrofusion fittings have been passed through the gap between adjacent metal pipe length (1) ends, that are subsequently welded. The electrical leads remain in the weld metal as a contaminant that can be harmful to the integrity of the weld, and the objection of the invention is to eliminate the problem. The objection is met by a construction of electrofusion fitting comprising a tubular length of thermoplastic material (3), of an outer diameter commensurate with the inner diameter of the ends of a compatible thermoplastic material lining of adjacent lengths of metal pipe (1), there being at each end of the fitting at least two heater coils on or in close proximity to the outer surface of the fitting, electrical leads from the heater coils extending through the fitting to emerge at the inner surface of the tubular length, for connection to a source of electrical power. |
