| 摘要 |
PURPOSE: To eliminate the scrape process, and improve workability at the time when plastic pipes are joined, in the plastic pipes, the junctions of which are made up of at least two layers, by making the fluidity of the surface layer greater than that of the inside layer. CONSTITUTION: When plastic pipes 10 are joined, the tips of the pipes 10 are inserted into sockets 18 of a joint 16, the joint 16 and the pipes 10 are fixed by use of a fixing tool, and a work coil 26 is arranged around the joint 16. In this state, when high frequency power is given from a high frequency power supply 28 to the work coil 26, high frequency current is given to a magnetic alloy heater 22 of the joint 16 by electromagnetic induction, and the heater 22 suddenly release heat by the skin effect to melt the outside surface of the pipes 10 and the inside surface of the joint 16 at the temperatures close to Curie temperature. At this time, the surface layer 14 of great fluidity flows together with oxide films and dirty layers, and a new, molten plastic of the inside layer 12 appears on the joining surfaces. Thus, the molten plastic of the inside layer 12 and the molten plastic of a joint body 20 are mixed and fused with each other. |
