Bad sealing performance:
1. There is a problem with the structure of the fiber optic splice closure
At present, the fiber optic splice closures used in optical cable projects are mostly not equipped with moisture conditions. They are buried underground when the construction workers complete the assembly process in accordance with the requirements of the subsequent process, and their sealing performance cannot be judged.
2. Influence of external conditions
The optical cables buried near the railway subgrade and on the shoulders of the railway are affected by surface movements, vibrations of trains, and changes in the ground temperature. Vertical and horizontal torsional forces and pressures are generated at the joints, resulting in deformation of the sealed parts of the optical fiber splice closures, resulting in closed failures. At present, the leakage of the integrated optical cable joints in use is blocked, and the fastening screws of sealed fiber optic splice closure that are buried underground for a long time are loosened.
3. Fiber optic splice closure seal material deterioration
Due to the above reasons, a part of the fiber optic splice closure is buried in the ground in a poorly sealed state, and it will inevitably lead to the influx of water for a long time, resulting in an increase in the loss of the optical fiber and an adverse consequence of the deterioration of the transmission quality.
1. Increase the sealed experimental conditions. A valve is temporarily installed on the air release hole of the sealing joint box. When the adhesive material is solidified, the air filling test is conducted. After confirming that the joint is sealed properly, the valve is removed, and the bleeder bolt is tightly sealed to prevent corrosion.
2. Strengthen the sealing performance. In the cable and cable project, in order to prevent the increase of the water level in the human hole, the heat shrinkable polyethylene seal layer is added to the outer layer of the joint box or the joint box is sealed and sealed. This method is also suitable for fiber optic connectors with harsh environmental conditions.