Abstract: A fiber optic cable is used as a distributed temperature sensing (DTS) transducer for temperature profile measurements in a protective underground duct in which a high voltage (HV) cable has already been laid. The sensing cable is not incorporated into the power cable itself, and in some installations does not have direct physical contact with the HV cable. The sensing cable is installed externally (along side) of the HV power cable, either in direct surface contact with the HV cable, or alternatively, the fiber optic sensing cable is installed in a small diameter guide tube that is placed in the upper annulus between the HV cable and the protective duct. The sensing fiber and one or more guide tubes are installed in a loose bundle at least in part by fluid drag forces (blowing with pressurized air) using conventional cable launching equipment.

Abstract: A fiber optic cable is used as a distributed temperature sensing (DTS) transducer for temperature profile measurements in a protective underground duct in which a high voltage (HV) cable has already been laid. The sensing cable is not incorporated into the power cable itself, and in some installations does not have direct physical contact with the HV cable. The sensing cable is installed externally (along side) of the HV power cable, either in direct surface contact with the HV cable, or alternatively, the fiber optic sensing cable is installed in a small diameter guide tube that is placed in the upper annulus between the HV cable and the protective duct. The sensing fiber and one or more guide tubes are installed in a loose bundle at least in part by fluid drag forces (blowing with pressurized air) using conventional cable launching equipment.

Abstract: Method for, using a fluid under pressure, installing optical fibers or cables in a tubular section comprising a supply tube and an intallation tube, each having an input and an output, the output of the supply tube being in connection with the input of the installation tube, a fluid under pressure being fed near the input of the supply tube, and the cable being conducted into the input of the supply tube and being propelled through the tubular section by the entraining force of the fluid, at least part of the fluid being discharged from the supply tube at the output of the supply tube and, at the input of the installation tube, a second fluid under pressure being fed. Due to said measures, the pressure drop at the input of the tubular section may be overcome without utilizing mechanical means which might damage the fiber or cable.

Abstract: A filling body is inserted together with a loose bundle of guide tubes during installation into the passage space of a protective duct, thus enlarging the bundle diameter (which reduces the buckling risk) and making crossing of the guide tubes impossible. The guide tubes are positioned along the outside of the filling body, providing access to the guide tubes during post-installation branching. The filling body may include radially projecting spacer ribs that separate the guide tubes, thereby preventing crossing movement and helical stranding. The guide tubes are thus constrained and carried along with the filling body in alignment with the spacer ribs, so that buckling, helical stranding and three-dimensional restrictions or tangles cannot occur.

Abstract: A filling body is inserted together with a loose bundle of guide tubes during installation in an existing protective duct, thus enlarging the bundle diameter (which reduces the buckling risk) and making crossing of the guide tubes impossible. The guide tubes are positioned along the outside of the filling body, providing access to the guide tubes during post-installation branching. The filling body may include radially projecting spacer ribs that separate the guide tubes, thereby preventing crossing movement and helical stranding. The guide tubes are thus constrained and carried along with the filling body in alignment with the spacer ribs, so that buckling, helical stranding and three-dimensional restrictions or tangles cannot occur. The filling body may include a thin tubular sidewall enclosing a longitudinal airflow passage that may be pressurized during installation, and deformable when unpressurized, thus providing mechanical protection against damage of the protective duct after installation.

Abstract: A cable straightener removes mini-bends from cable as it is unwound from a reel for installation in an underground duct, providing improved blowing performance for any cable with non-negligible stiffness and that exhibits reel-set or shape memory recovery, for example cables enclosed within small diameter tubular steel jackets, cables enclosed within aluminum laminated polymer sheets, and cables enclosed within hard polymer tubing. Residual stresses induced in such cables are reduced by first and second sets of straightener rollers prior to pushing/blowing installation.

Abstract: A cable is installed in a guide tube by means of blowing (and, optionally, synergetic pushing) and lubricating the cable during this installation. Lubricating the cable is done after the cable has passed the cable blowing equipment and hence takes place in a pressurized airflow passage. A hollow chamber filled with foam-plugs saturated with lubricant forms the cable lubricator. To avoid buckling, cable guide blocks are placed, which also divide the lubricator in different sub-chambers, each with its own foam-plug and content of lubricant. The airflow, needed to propel the cable during blowing, can bypass the lubricator.

Abstract: Method and device for installing cables in ducts using a pressurized fluid, a fluid being applied which, under the operational pressure and operational temperature applied during the installation, is in a liquid state and which, under the ambient pressure and ambient temperature prevailing at the location of the installation, is in gaseous state. By applying such a fluid, the advantages of installing a cable using a liquid flow and using a gas flow may be combined, while the drawbacks respectively associated therewith are obviated.

Abstract: An existing protective duct contains a bundle of guide tubes through which fiber optic cables are run to customers at existing service locations. In order to run a cable to a new customer at a different service location, the duct is cut at a branch point and a short section of the duct is removed to expose the guide tubes. An unused guide tube is cut and serially connected to a branch guide tube leading to the new service location. The protective duct sidewall is restored at the branch point by a splittable Y-branch connector that includes complementary housing sections, an inlet opening, an outlet opening and at least one branch opening. Splittable coupling collars seal the branch connector housing sections around the respective cut end portions of the existing duct. The Y-branch connector also includes a branch stub that is sealed around the branch guide tube.

Abstract: Fiber density and installation length are improved by enclosing optical fibers in a very small diameter metal jacket, resulting in increased cable stiffness and durability. The metal jacket consists of a small diameter, thin sidewall laser-welded steel tube that is loosely filled with optical fiber strands and a gel waterproofing material that provides a longitudinal water-barrier. The fibers are free to “float” within the steel jacket, and thus are decoupled from external mechanical forces and stresses that act on the cable during installation. When bundles of the steel-jacketed fiber optic cables are installed with pushing and blowing, about twice the installation length is reached as compared with pure blowing. Also, the number of cables and fiber density in each guide tube can be increased, thus increasing the fiber capacity of the feeding ducts and branch ducts of a fiber optic communications network.

Abstract: Guide tubes are arranged in a loose bundle and are fed into an existing tubular conduit or protective duct by a powered tractor and are pulled through the duct by the volumetric flow of compressed air which is introduced into the inlet end of the duct. The guide tubes are pressurized and closed at their leading end and trailing end. The existing duct is open at both ends. When the filling degree of the guide tube bundle (sum of guide tube cross-sectional areas compared to that of channelization duct) is provided in the range of from about 30% to about 60%, blowing/pushing installation of the guide tube bundle is substantially trouble free, and the bundle of guide tubes can be installed in a flexible and efficient manner over relatively greater distances.

Abstract: A method for installing branches in a protective ducting system in which guide tubes and cables have already been laid, wherein at a desired branch location in the protective duct, a splittable Y-branch connector with an inlet opening, an outlet opening and at least one branch opening is installed by cutting a short section from the duct at the desired branch point and exposing the guide tubes and cables, opening the splittable branch connector and arranging it around the exposed guide tubes and cables, and closing and securing the Y-branch connector with splittable coupling collars in such a manner that the inlet opening and the outlet opening engage in sealing manner over the respective cut ends of the existing duct, and the branch opening of the connector is secured by engagement of a branch stub around a branch duct through which a branch guide tube is laid.

Abstract: Method and device for installing cables in ducts using a pressurized fluid, a fluid being applied which, under the operational pressure and operational temperature applied during the installation, is in a liquid state and which, under the ambient pressure and ambient temperature prevailing at the location of the installation, is in gaseous state. By applying such a fluid, the advantages of installing a cable using a liquid flow and using a gas flow may be combined, while the drawbacks respectively associated therewith are obviated.

Abstract: Method for, using a fluid under pressure, installing optical fibers or cables in a tubular section comprising a supply tube and an intallation tube, each having an input and an output, the output of the supply tube being in connection with the input of the installation tube, a fluid under pressure being fed near the input of the supply tube, and the cable being conducted into the input of the supply tube and being propelled through the tubular section by the entraining force of the fluid, at least part of the fluid being discharged from the supply tube at the output of the supply tube and, at the input of the installation tube, a second fluid under pressure being fed. Due to said measures, the pressure drop at the input of the tubular section may be overcome without utilizing mechanical means which might damage the fiber or cable.

Abstract: A filling body is inserted together with a loose bundle of guide tubes during installation in an existing protective duct, thus enlarging the bundle diameter (which reduces the buckling risk) and making crossing of the guide tubes impossible. The guide tubes are positioned along the outside of the filling body, providing access to the guide tubes during post-installation branching. The filling body may include radially projecting spacer ribs that separate the guide tubes, thereby preventing crossing movement and helical stranding. The guide tubes are thus constrained and carried along with the filling body in alignment with the spacer ribs, so that buckling, helical stranding and three-dimensional restrictions or tangles cannot occur. The filling body may include a thin tubular sidewall enclosing a longitudinal airflow passage that may be pressurized during installation, and deformable when unpressurized, thus providing mechanical protection against damage of the protective duct after installation.

Abstract: A cable comprises a cable body (1) provided with a tubular cavity (2) for including a stack (4) having a number of fibre ribbons (5), and with a preferred bending plane (X-X), e.g. through two strength elements (3) located in the cable body on either side of the cavity (2). The cavity has a mainly rectangular cross section and is provided with a pair of opposite sidewalls (2.1, 2.2), at any rate substantially, parallel to the preferred bending plane (X-X). The stack also comprises a spacer (6), included in such a manner that the stack fills the tubular cavity with some play, and the pair of opposite sidewalls provide upper and lower bounds of the stack. The said sidewalls preferably have a slight transverse convexity. The cable may be manufactured complete. The cable may also be completed after prior empty installation of the cable body. The cable permits very high fibre densities and allows for upgrading.

Abstract: A cable straightener removes mini-bends from cable as it is unwound from a reel for installation in an underground duct, providing improved blowing performance for any cable with non-negligible stiffness and that exhibits reel-set or shape memory recovery, for example cables enclosed within small diameter tubular steel jackets, cables enclosed within aluminum laminated polymer sheets, and cables enclosed within hard polymer tubing. Residual stresses induced in such cables are reduced by first and second sets of straightener rollers prior to pushing/blowing installation.

Abstract: A cable straightener removes mini-bends from cable as it is unwound from a reel for installation in an underground duct, providing improved blowing performance for any cable with non-negligible stiffness and that exhibits reel-set or shape memory recovery, for example cables enclosed within small diameter tubular steel jackets, cables enclosed within aluminum laminated polymer sheets, and cables enclosed within hard polymer tubing. Residual stresses induced in such cables are reduced by first and second sets of straightener rollers prior to pushing/blowing installation.

Abstract: Method and device for installing cables in ducts using a pressurized fluid, a fluid being applied which, under the operational pressure and operational temperature applied during the installation, is in a liquid state and which, under the ambient pressure and ambient temperature prevailing at the location of the installation, is in gaseous state. By applying such a fluid, the advantages of installing a cable using a liquid flow and using a gas flow may be combined, while the drawbacks respectively associated therewith are obviated.

Abstract: A method for installing a ducting system with branches, wherein at the point of a branch in an existing duct of the system a splittable Y-branch connector with an inlet opening, an outlet opening and at least one branch opening is installed by cutting a duct portion from the existing duct at the point of the branch, opening the splittable branch connector and arranging it around a bundle of guide tubes extending between the cut end portions of the duct, and closing and securing the Y-branch connector with splittable coupling collars in such a manner that the inlet opening and the outlet opening engage in sealing manner over the respective cut ends of the existing duct, and the branch opening is secured by engagement of a branch stub around a branch duct through which a branch guide tube is laid.