| 摘要 |
<p>PURPOSE:To prevent degradation of the carrying speed of an optical cable due to residual matter by supplying gas into a conduit and carrying the cable toward the downstream thereby removing residual matter from the conduit. CONSTITUTION:Collecting pipes 17 are laid while being coupled through joints 20, 21 arranged with a predetermined interval in an underground pit 19. When an optical fiber 11 is laid while being fed forcedly through gas, dry gas is pressure fed for a predetermined time into a pipe 15 to be inserted with the cable 11 in order to remove residual water or dust from the pipe. In other words, the joint pipe 27 of a cable force feeder 26 is coupled to the end of an extension pipe 22 at position A and gas is pressure fed into the extension pipes 22, 24 and the cable pipe in the collecting pipe 17, then residual water in each pipe is discharged together with dust from the end section of the extension pipe 24 at a position B while being evaporated partially.</p> |
