| 摘要 |
PURPOSE:To prevent a fluid from leaking by making a weld into a desired thickness by a method wherein an electrode is brought into contact with the weld of a sheet or tube made of thermoplastic resin, an electrode whose quantity of electric charge per unit area is little and contact area is large is brought into contact with a part facing on the same and high-frequency voltage is applied to a space between the two electrodes by possessing a metallic pipe for its intermediate electrode. CONSTITUTION:A contacting face 6 of an electrode 2 becoming a weld joint side is made into a state of a circular arc and an electrode 3 is made into a state of a curved surface, therefore, a contacting area is sufficiently large. In case of coating where the inside diameter of a pipe 9 is small and a flange part 10 is included, a tube 11 made of polyurethane resin is provided within a pipe and a coating material 14 made of resin where a flange part 13 has been formed is arranged. Then as a contacting area of the electrode 3 with the coating material 14 is larger than that of the electrode 2, a dielectric heating action is acted upon strongly at an electrode side for weld. The weld is formed annularly by turning a holding tool 4 along the circumference of the metallic pipe 9. In this instance, the metallic pipe 9 acts as an intermediate electrode. A quantity of dielectric heating can be controlled easily by selecting voltage and frequency. |
