Electrofusion socket with fusion state indicating means.

摘要

An electrofusion method in which an electrofusion joint having an electrical heating wire (11) embedded in the inner peripheral region thereof is fitted on or laterally pressed against an end of a resin pipe and electrical currentis supplied to the electrical resistance heating wire so as to melt and fuse the electrofusion joint. The joint is beforehand provided with an annular groove formed in the outer peripheral surface of the joint to reach a region near the electrical resistance heating wire. The annular groove defines a pin- or bar-like core which serves as a pressure-transmitting member such that any rise in the pressure due to fusion of the joint is detected by a pressure switch through the core, and the supply of the electrical current is terminated in response to detection of the pressure by the pressure switch through the core. Disclosed also is a method of confirming the state of fusion of an electrofusion joint in which the joint is beforehand provided with a detection hole (14) formed in the outer peripheral surface of the joint to reach a region near the electrical resistance heating wire. The detection hole is covered with a lid (15) of heat-resistant material during execution of the electrofusion process. The state of flowing of molten resin into the detection hole during execution of the electrofusion process is inspected through the lid and whether the fusion has been done successfully is confirmed by removing the lid after solidification of the resin. Also disclosed is an electrofusion joint comprising a detection hole formed in the outer peripheral surface of said joint to reach a region near said electrical resistance heating wire, a transparent or translucent heat-resistant lid embedded in or fixed to said joint so as to close said detection hole. Further disclosed is an electrofusion joint having an annular groove formed in the outer peripheral surface of said joint to reach a region near said electrical resistance heating wire, so as to define a pin- or bar-like core, and a stopper member provided above said core and capable of limiting the lift of said core.