| 摘要 |
A duct for containing a cable and method for mounting the cable therein include providing the duct with a collapsible or flexible wall movable between a contracted condition for mounting the duct in a conduit and an extended condition of increased cross-sectional area for inserting a cable in the duct. The duct is moved to its extended condition by an applied internal pressure and, after the cable has been inserted, the duct is returned to its contracted condition. The duct has a multiple layer construction: an inner layer, an outer protective layer and a reinforcing layer between them. There may be frictional reducing ribs on the inner and/or outer layer in order to reduce the forces necessary to place the duct and/or the cable. Alternatively, the duct may have a single, thin layer.
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