| 摘要 |
There is disclosed a method of fabricating welded branched pipe connections from weldable thermoplastic materials, such as polyethylene, which includes shaping the end of a branch pipe section to the curvature of a main pipe section, simultaneously heating the shaped end of such branch pipe section and an annular zone of the main pipe section to a welding temperature, pressing the heated shaped end into the heated annular zone of the main pipe section to weld the sections and applying pressure to the material of the sections on both the inner and outer sides of the intersection between the branch pipe section and the main pipe section, while precluding spreading of the sections in a direction perpendicular to the direction in which the sections are pressed together so as to deform the material of the heated annular zone of the main pipe section upwardly into the material of the branch pipe section to increase the area of welding contact. There is also disclosed a press tool for use in such method, which includes outer and inner sleeve means spaced to accommodate a branch pipe section and such sleeves having shaped pressure applying end portions, operative to deform the cross-sectional welding line of contact into a raised lip or hump to increase the area of welding contact.
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