| 摘要 |
PURPOSE: To generate a sufficient welding pressure to welding connection without generating a bead or cavity by disposing a bladder for pressing the inner circumference of the tubular components on a welding connection region at the time of expanding. CONSTITUTION: A heater 2 having a pair of heating jaws 2a, 2b is arranged on outer circumferences of both ends of tubular components 1a, 1b to be welded made of a thermoplastic material. A supporting unit 3 formed as a bladder 4 is arranged in an inner space of the components 1a, 1b. An electric heating element 9 such as, for example, a heating cartridge is arranged in an inner space 8 of the bladder 4. Thermally expandable fluid 10 such as water, synthetic oil or the like is fully filled therein. Prior to starting of welding, a current is supplied to the element 9 in the bladder 4. As a result, the bladder 4 is expanded so that a cylindrical part 7 is brought into contact with inner circumstances of the components 1a, 1b with adjustable pressure. During a welding work, a necessary welding pressure is generated by the heater 2 disposed outside. |
