| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate flow obstruction in sewer even though an optical fiber cable is inserted into a sewer pipe in operation by applying a smoothing process to the external periphery of the cable. SOLUTION: The external periphery of an optical fiber cable, which is to be inserted into a sewer pipe in operation, is covered by a smoothing material so that dirt and solid bodies hardly adhere to the cable.</p> |
