| 摘要 |
PURPOSE:To keep a hard thermoplastic resin pipe flat even when it is heated and insert the pipe easily into a conduit run by folding the pipe into flatness, blocking both ends of the pipe airtightly, bending the pipe to make the cross section almost a V or U shape, inserting the pipe into the conduit run, and expanding the pipe by applying hot pressurized fluid to the pipe. CONSTITUTION:A synthetic resin pipe 1, which is preferably made of rigid high density polyethylene or linear low density polyethylene, is folded into flatness, wound on a reel, and blocked by filler airtightly. The pipe 1 is passed trough a heater, softened by hot air supplied from a hot air supply pipe 6, pressed on its middle part by a rotary roller 7 to be bent with the cross section made almost a V or U shape, and inserted into the conduit run 2. The resin pipe 1 the end of which is connected with a draw wire 8 previously inserted into the conduit run 2 is drawn by the wire 8 to be inserted into the conduit run 2. The end of the pipe 1 is cut, and the pipe is expanded by applying pressurized steam to make it cylindrical so that the pipe runs along the inside of the conduit run 2. |
