| 摘要 |
PROBLEM TO BE SOLVED: To dispense with transportation of a pressure gas source into an insertion place by connecting the pressure gas source and an insertion device body by a gas transport pipeline, and installing the pressure gas source in a place distant from the insertion device body. SOLUTION: An insertion device 4 has an insertion device body and a feed roller. A pressure gas source 5 and the insertion device body are connected by a gas transport pipeline 6, and the pressure gas source 5 is installed in a place distant from the insertion device body. The gas transport pipeline 6 is composed of an empty gas transport pipeline 22c without an optical fiber inserted through out of pipelines 22 at a lower part 1b of a vertical cable, a gas transport pipeline 6a with one end connected to a gas supply hole, and a gas transport pipeline 6b with one end connected to the pressure gas source 5. In the case of arranging a plurality of such gas transport pipelines 6 in parallel, the pressure loss of gas in the gas transport pipe 6 is reduced, which is desirable. |
