亚洲精品影片,精品久久久久国产免费,精品久久久久99,国产精品区一区,国产成人一区在线观看,国产成人精品优优av,国产精品久久久久久久午夜

Mining optical cables are made by inserting single-mode or multi-mode optical fibers into loose tubes made of high modulus plastic, and filling the tubes with water-resistant compounds. The center of the cable core is a phosphated steel wire or a steel wire rope extruded with polyethylene. A loose sleeve (or filling rope and signal line) is twisted around the center to strengthen the core and form a compact and circular cable core. The gaps inside the cable core are filled with water-resistant filling material, steel polyethylene bonded inner sheath, and blue flame-retardant PVC sheath to form the cable. The mining optical cable has a flame-retardant sheath, which can have a full section water-resistant structure to ensure good water and moisture resistance. The loose sleeve is filled with special grease to provide critical protection for the optical fiber.