| 摘要 |
<p>PURPOSE:To easily allow an optical fiber cable to insert through, by forming smoothly the inside peripheral wall surface of a conduit line, and also, forming a recessed groove along the peripheral direction of the conduit line on the outside peripheral wall surface of the conduit line. CONSTITUTION:The inside peripheral wall surface of a conduit line 3 is formed smoothly, and also, on the outside periphery of the wall surface of a cylindrical pipe 1, four pieces of recessed grooves 2 are carved and provided at a prescribed pitch in a form to be surrounded in the peripheral direction of the pipe 1, while drawing a slow spiral in the longitudinal direction of the pipe 1. In this state, when a fluid of a gas medium, etc. is allowed to flow at a higher speed than an advance speed of an optical fiber cable in the direction for advancing the cable into the conduit line 3, since a contact resistance of the inner peripheral wall surface of the conduit line, the optical fiber cable can be inserted through smoothly. Also, even if bending or twist is applied to the conduit line 3, the influence of a residual strain can be reduced by the recessed groove 2 of the outer peripheral wall surface of the conduit line 3.</p> |
