| 摘要 |
PURPOSE:To permit the pressing expansion of a pipe smoothly without any unnatural enforcement, by a method wherein the expansion of the pipe as well as adhesive coating on the inner surface of a pipeline are effected while heating the pipe by heating fluid from the outside of the pipe simultaneously with the heating of the pipe from the inside thereof under compression. CONSTITUTION:Secondary steam from a secondary boiler 9 is supplied into a plastic pipe 1 while the plastic pipe 1 is heated from the outside thereof by primary steam from a primary boiler 3. After plastic pipe 1 is heated and softened, the pressure of the secondary steam in the plastic pipe 1 is increased so as to be higher than the pressure of the primary steam at the outside of the pipe 1, then, the plastic pipe 1 is expanded radially by a pressure difference and an expanded pipe 1' is adhered to the inner surface of a pipeline (a) to coat it. Subsequently, the supply of the primary and secondary steam is stopped and the expanded pipe 1' is cooled and solidified while holding the inside of the pipe under a predetermined pressure, thereafter, the remaining end of the expanded pipe 1' is cut to remove it. |
