Usually, the optical cable and the cable are laid in a damp and dark environment. If the cable is damaged, the moisture will enter the cable along the damaged point and affect the cable. Water can change the capacitance in copper cables, reducing signal strength. It will cause excessive pressure on the optical components in the optical cable, which will greatly affect the transmission of light. Therefore, the outside of the optical cable will be wrapped with water-blocking materials. Water blocking yarn and water blocking rope are commonly used water blocking materials. This paper will study the properties of the two, analyze the similarities and differences of their production processes, and provide a reference for the selection of suitable water-blocking materials.
1.Performance comparison of water blocking yarn and water blocking rope
(1) The properties of water blocking yarn
After the test of water content and drying method, the water absorption rate of the water blocking yarn is 48g/g, the tensile strength is 110.5N, the breaking elongation is 15.1%, and the moisture content is 6%. The performance of the water blocking yarn meets the design requirements of the cable, and the spinning process is also feasible.
(2) The performance of the water blocking rope
Water blocking rope is mainly a water blocking filling material required for special cables. It is mainly formed by dipping, bonding and drying of polyester fibers. After the fiber is fully combed, it has high longitudinal strength, light weight, thin thickness, high tensile strength, good insulation performance, low elasticity, and no corrosion.
(3) The main craft technology of each process
For water blocking yarn, carding is the most critical process, and the relative humidity in this processing is required to be below 50%. The SAF fiber and polyester should be mixed in a certain proportion and combed at the same time, so that the SAF fiber during the carding process can be evenly dispersed on the polyester fiber web, and form a network structure together with the polyester to reduce its falling off. In comparison, the requirement of the water blocking rope at this stage are similar to those of the water blocking yarn, and the loss of materials should be reduced as much as possible. After scientific proportion configuration, it lays a good production foundation for the water blocking rope in the process of thinning.
For the roving process, as the final process, the water blocking yarn is mainly formed in this process. It should adhere to slow speed, small draft, large distance, and low twist. The overall control of the draft ratio and the basis weight of each process is that the yarn density of the final water blocking yarn is 220tex. For the water blocking rope, the importance of roving processis not as important as the water blocking yarn. This process mainly lies in the final processing of the water blocking rope, and in-depth treatment of the links that are not in place in the production process to ensure the quality of the water blocking rope.
(4) Comparison of the shedding of water-absorbing fibers in each process
For water blocking yarn , the content of SAF fibers gradually decreases with the increase of the process. With the progress of each process, the reduction range is relatively large, and the reduction range is also different for different processes. Among them, the damage in the carding process is the largest. After experimental research, even in the case of an optimal process, the tendency to damage the noil of SAF fibers is unavoidable and cannot be eliminated. Compared with the water blocking yarn, the fiber shedding of the water blocking rope is better, and the loss can be minimized in each production process. With the deepening of the process, the fiber shedding situation has improved.
2. Application of water blocking yarn and water blocking rope in cable and optical cable
With the development of technology in recent years, water blocking yarn and water blocking rope are mainly used as internal fillers of optical cables. Generally speaking, three water blocking yarns or water blocking ropes are filled in the cable, one of which is generally placed on the central reinforcement to ensure the stability of the cable, and two water blocking yarns are generally placed outside the cable core to ensure that the water-blocking effect can be achieve the best. The use of water blocking yarn and water blocking rope will greatly change the performance of the optical cable.
For the water-blocking performance, the water-blocking performance of the water blocking yarn should be more detailed, which can greatly shorten the distance between the cable core and the sheath. It makes the water blocking effect of the cable better.
In terms of mechanical properties, the tensile properties, compressive properties and bending properties of the optical cable are greatly improved after filling the water blocking yarn and the water blocking rope. For the temperature cycle performance of the optical cable, the optical cable after filling the water blocking yarn and the water blocking rope has no obvious additional attenuation. For the optical cable sheath, the water blocking yarn and the water blocking rope are used to fill the optical cable during forming, so that the continuous processing of the sheath is not affected in any way, and the integrity of the optical cable sheath of this structure is higher. It can be seen from the above analysis that the fiber optic cable filled with water blocking yarn and water blocking rope is simple to process, has higher production efficiency, less environmental pollution, better water-blocking effect and higher integrity.
After comparative research on the production process of water blocking yarn and water blocking rope, we have a deeper understanding of the performance of the two, and have a deeper understanding of the precautions in the production process. In the application process, reasonable selection can be made according to the characteristics of the optical cable and the production method, so as to improve the water blocking performance, ensure the quality of the optical cable and improve the safety of electricity consumption.