Air blown fiber optic cable installation is a method in which high-pressure airflow is used to blow and place fiber optic cables into pre-installed ducts or conduits. A blowing machine delivers high-pressure and high-speed compressed air into the duct, pushing an air seal piston. This air seal piston, connected to the end of the fiber optic cable, creates a controlled and uniform tension on the cable. Simultaneously, the blowing machine's hydraulic caterpillar conveyor mechanism grips the cable and moves it forward, creating a pushing force. The combination of tension and pushing force allows the fiber optic cable to travel rapidly through the conduit in a suspended state along with the high-speed airflow. The trend in telecommunication backbone fiber optic cable installation is towards using ducts or conduits.
Previously, fiber optic cables were installed using cement pipes (which are no longer used due to complex construction and high friction) or PVC plastic pipes. The conventional method involved pulling the cable through the pipeline, but this method had limitations such as short cable pulling distances, slow speeds, and the potential for mechanical strain on the fiber. To address the lubrication issue on the pipeline's inner wall during cable installation, lubricants were applied to the inner surface. However, due to gravity, the lubricant would not evenly distribute along the entire inner wall and could be carried away by the dry portion of the cable. Lubrication directly affects the length and speed of cable installation.
Currently, silicon core plastic ducts are extensively manufactured in China. These ducts are made of high-density polyethylene, and their unique feature is the simultaneous extrusion of silicone gel onto the inner wall of the high-density polyethylene pipe, forming a solid and permanent lubrication layer. This lubrication layer possesses the same physical and mechanical properties as high-density polyethylene, maintaining its shape even under pressure. The friction coefficient between the inner wall of the silicon core duct and the fiber optic cable is less than 0.15, which is 60%-70% lower than that of a standard plastic conduit. This significantly reduces the friction between the cable and the conduit, allowing for longer cable installation distances and creating favorable conditions for the promotion of air blown fiber optic cable installation.
The main characteristics of air blown fiber optic cable installation are as follows:
Compared to other cable installation methods, the tension experienced by the cable during installation is more uniform and significantly lower.
The installation process is simplified, and the cable can be installed at a higher speed.
Longer installation distances can be achieved, allowing for the use of longer cable reels, reducing the number of splices and lowering signal loss.
The number of manholes and handholes required along the pipeline can be greatly reduced.
The labor required for installation is significantly reduced.
