| 摘要 |
PURPOSE:To stabilize longitudinal dimension of a tube lining by, after forming hard tubular lining, locally reheating the lining in a longitudinal direction of the lining to eliminate internal residual stress. CONSTITUTION:Hard tubular lining 1' formed inside a tube 2 by hot pressure expansion method is air-cooled under pressure and solidified and then excessive ends are cut and removed. An axially movable heating device 3 is provided within the lining 1'. The device 3 includes a center shaft 4 and a pair of slide plugs 5, 5' fixed to the opposite ends of the shaft and the interior of a heating chamber 6 defined between the plugs 5, 5' is connected to a heating fluid supply source through a passage 7 of heating fluid, e.g. steam, formed in the plug 5 on the rear side and a pipe 8. Steam is supplied into the chamber 6 of the device 3 to heat a section 1'a of the lining so that the lining is uniformly softened in a thickness direction. In this manner, local heating is applied repeatedly over the entire length of the tube to eliminate stress which causes contraction with the passage of time in a longitudinal direction. |
