Among the quality problems of fiber closures, the biggest problem is the sealing performance. The poor sealing of the fiber closure will cause the fiber closure to enter the water, and the direct buried circuit may even have the phenomenon that muddy water is poured into the fiber closure. After entering the water, the fiber closure can cause the following hazards: the optical fiber is in a high-humidity environment, the coating layer is easy to fall off, the fiber attenuation will increase slowly, affecting the transmission quality, thereby affecting the fatigue life of the fiber; destroying the strong electric protection system the induced vertical potential accumulates and grows, endangering the human body and equipment safety; when the powerful lightning strike current invades, the water vaporizes, the violent expansion impacts the optical fiber to break it, and even the fiber closure bursts; the impurities in the water erode the optical fiber, and some Pipeline wastewater has a high pH and is more harmful to fiber. When the overhead fiber closure enters the water and freezes in the winter, the fiber is squeezed, resulting in an increase or breakage of the fiber.
This phenomenon occurs in the actual line:
The fiber closure seal rubber strip and the box body are non-adhesive, the water in the box is filled, the connecting bracket is severely rusted, and the coating layer on the bare fiber in the fiber board is aging, which has become powdery and most of it has fallen off; the fiber fusion joint is strengthened. The steel wire in the core is corroded, the hot melt tube is deformed, and air bubbles are found in the individual hot melt tubes. These conditions may cause the attenuation value of the optical fiber to increase or even break, resulting in the fiber being unusable.