Collapsible duct

Abstract

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.

1 - 60 . (canceled)  
     
     
         61 . A method of installing a cable in an inner pathway comprising the steps of: 
 providing a thin wall duct having a duct wall including a collapsible wall to form said inner pathway, said collapsible wall being movable between an extended condition to provide the duct with a first cross-sectional area and a contracted condition to provide said duct with a second cross-sectional area smaller than said first cross-sectional area,    moving said collapsible wall to said extended condition to provide said thin wall duct with said first cross-sectional area,    inserting said cable into said thin wall duct with said collapsible wall in said extended condition, and    moving said collapsible wall to said contracted condition with said cable extending through said thin wall duct within said conduit.    
     
     
         62 . The method of  claim 61 , wherein the thin wall duct is formed of single plastic material having a flexural modulus of up to about 400 kpsi and a tensile strength of from about 5000 psi to about 12,000 psi.  
     
     
         63 . The method of  claim 62 , wherein said duct wall has a wall thickness between and including 0.003″ and 0.012″.  
     
     
         64 . The method of  claim 63 , wherein said duct wall is made of polyethylene terephthalate.  
     
     
         65 . The method of  claim 63 , wherein said thin wall duct is made of a plastic selected from the group consisting of polyesters, polyamides, styrenic polymers, polycarbonates, polyaryletherketone, polyetheretherketone, polyetherimide, and polyphenylenesulfides.  
     
     
         66 . The method of  claim 61 , further including providing a conduit having a conduit space into which said thin wall duct is to be positioned and inserting said thin wall duct with said collapsible wall in said contracted condition into said conduit space.  
     
     
         67 . The method of  claim 66 , wherein said conduit space includes a prior duct previously positioned in said conduit space, and the step of inserting said thin wall duct into said conduit space includes positioning said thin wall duct adjacent to said prior duct.  
     
     
         68 . The method of  claim 66 , wherein said conduit space includes a prior cable previously positioned in said conduit space, and the step of inserting said thin wall duct into said conduit space includes positioning said thin wall duct adjacent to said prior cable.  
     
     
         69 . The method of  claim 67 , wherein said duct wall is formed of a plurality of layers including an inner layer.  
     
     
         70 . The method of  claim 69 , wherein said inner layer is formed of a low friction material to facilitate the insertion of said cable into said pathway provided by said thin wall duct.  
     
     
         71 . The method of  claim 69 , wherein said conduit is mounted outdoors and exposed to the weather.  
     
     
         72 . A method of retrofitting a conduit having a conduit space containing a first duct with a second duct providing an inner pathway extending in said conduit space separate from said first duct comprising the steps of: 
 providing said second duct as a thin wall duct having a duct wall including a collapsible wall movable between an extended condition to provide the thin wall duct with a first cross-sectional area and a contracted condition to provide thin wall duct with a second cross-sectional area smaller than said first cross-sectional area,    inserting said thin wall duct with said collapsible wall in said contracted condition into said conduit space adjacent to said first duct,    moving said collapsible wall to said extended condition to provide said thin wall duct with said first cross-sectional area,    inserting said cable into said thin wall duct with said collapsible wall in said extended condition, and    moving said collapsible wall to said contracted condition with said cable extending through said thin wall duct within said conduit.    
     
     
         73 . The method of  claim 72 , wherein said duct wall is formed of a plurality of layers including an inner layer.  
     
     
         74 . The method of  claim 73 , wherein said inner layer is formed of a low friction material to facilitate the insertion of said cable into said inner pathway provided by said thin wall duct.  
     
     
         75 . The method of  claim 74 , wherein said thin wall duct has a longitudinal axis and said duct wall extends about said axis to form said inner pathway within said conduit space.  
     
     
         76 . The method of  claim 74 , wherein said duct wall has a thickness in the range of from about 0.003″ to about 0.012″.  
     
     
         77 . The method of  claim 72 , wherein said thin wall duct is made of a plastic selected from the group consisting of polyaryletherketone, polyetherimide, polyphenylenesulfide, and polyetheretherketone, wherein the thin wall duct is inherently flame retardant and low spoke producing.  
     
     
         78 . A method of installing a cable in an inner pathway in a pipeline having a longitudinally extending pipeline axis surrounded by a closed pipeline wall comprising the steps of: 
 providing an inlet opening in said pipeline wall for receiving a duct having a duct wall including a collapsible wall to form said inner pathway, said collapsible wall being movable between an extended condition to provide the duct with a first cross-sectional area and a contracted condition to provide the duct with a second cross-sectional area smaller than said first cross-sectional area,    providing clamp means having an adjustable opening communicating with said inlet opening for receiving and introducing said duct into said pipeline, said adjustable opening being operable between a clearance position and a sealing position,    operating said clamp means to said clearance position to provide sufficient clearance to insert said duct into said adjustable opening,    inserting said duct into said adjustable opening and through said pipeline opening and into said pipeline with said collapsible wall in the contracted condition,    moving said collapsible wall to said extended condition to provide said thin wall duct with said first cross-sectional area,    installing a cable in said duct with said collapsible wall in said extended condition,    moving said collapsible wall to said contracted condition with said cable extending through said thin wall duct within said pipeline,    operating said clamp means to said sealing position engaging said collapsible wall in said contracted condition in a fluid tight seal, and    sealing said inlet opening with said duct containing said cable extending through said pipeline.    
     
     
         79 . The method of  claim 78 , wherein said pipeline is a utility service line for supplying a gas or water utility service, further including the step of interrupting the supply of said utility service during the installation of said cable in said pipeline.  
     
     
         80 . The method of  claim 78 , wherein said duct is a thin wall duct and said duct wall has a thickness in the range of from about 0.003″ to about 0.012″.  
     
     
         81 . The method of  claim 80 , wherein said duct wall is formed of a plurality of layers including an inner layer.  
     
     
         82 . The method of  claim 81 , wherein said inner layer is formed of a low friction material to facilitate the insertion of said cable into said inner pathway provided by said thin wall duct.