Cable jetting is the process of blowing a cable through a duct while simultaneously pushing the cable into the duct.
Compressed air is injected at the duct inlet and flows through the duct and along the cable at high speed.
(Preferably, no suction pig is used at the cable head.)
The high speed air propels the cable due to drag forces and pressure drop. The friction of the cable against the duct is reduced by the distributed airflow, and large forces that would generate high friction are avoided. Because of the expanding airflow, the air propelling forces are relatively small at the cable inlet and large at the air exhaust end of the duct. To compensate for this, an additional pushing force is applied to the cable by the jetting equipment.
Condux fibre optic cable blowing machines
The pushing force, acting mainly near the cable inlet, combined with the airflow propelling forces, increasing the maximum jetting distance considerably. Special lubricants have been developed for cable jetting to further reduce friction.