| 摘要 |
PROBLEM TO BE SOLVED: To scarcely generate a wrinkle along a bent tube part when an existing tube has the bent tube part while facilitating enlarging and deforming of a replaced tube inserted into the inside of the existing tube. SOLUTION: The method for replacing the existing tube for replacing the existing tube by providing a replacing tube B made of a thermoplastic resin at the inside of the existing tube A comprises the steps of radially deforming the replacing tube having an outer diameter radially movable to the existing tube in a state in which the replacing tube is provided at the inside of the existing tube so that the maximum outre diameter becomes smaller than the inner diameter of the existing tube, inserting the replacing tube into the inside of the existing tube, enlarging and deforming the replacing tube inserted into the inside of the existing tube by a heating fluid press injected in its inside, and providing the replacing tube at the inside of the existing tube in a state in which the replacing tube is isolated at an interval 12 from the inner periphery of the existing tube.
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