In the field of utility cable installation, there are existing techniques for using the viscous flow of a fluid, such as air, through ducts to install utility cables within the ducts. Such cable “blowing” techniques have been applied to the installation of utility cables in building risers, over relatively short distances along the ground, or in suspended cables.
Existing cable blowing techniques, however, are difficult to apply over distances spanning more than a few kilometers. The flow of a fluid through an extremely long and narrow duct becomes greatly impeded due primarily to viscous flow characteristics, resulting in a high back-pressure experienced at the originating end of the duct. This problem can limit the distances over which existing cable blowing techniques are applied, and can impose constraints on the types of ducts that can be used, as well as the types of cables that may be deployed within a given duct. Additionally, existing cable blowing techniques require that relatively high pressures be applied to the end of a duct through which a cable is being fed. These high pressures can result in duct “blow-outs,” where the high pressure causes ruptures in the walls of the duct, or sealing/clamping failures, where the seal between the duct and the unit applying pressurized fluid to the duct ruptures or fails.