| 摘要 |
There are presently two known types of protection for optical fibers: One being of the adhered type, which is characterized in that an extruded plastic material is applied over and into direct contact with the optical fiber. A second type utilizes slacked tubes as a protection over one or more fibers which are contained inside the tubes along with a filling material as a fiber protection against humidity penetration. The improvements to the optical cable are based on a construction of the slacked tube type, which are helicoidally or bi-directionally twisted (sz) about a light central element having a low mechanical memory. This central element constitutes a traction element when the cable is subjected to tension forces resulting from installation; and an element for balancing expansion and contraction forces caused by operation of the cable on the thermal rank limits thereof. An aramyde fiber or fiber-glass layer is applied over a core formed by the central element and slacked tubes, said fiber layer contributing together with the central element to reach a higher tension during installation. Over this set, one or more plastic covers, which serve as support to one or two longitudinally placed metallic covers are applied. A last plastic cover is applied as a final protection.
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