EP4107566A1 - Blocking for fiber optic cable - Google Patents

Abstract

Blocking of water and gas from an interior of the cable from passing into a closure includes applying blocking material to an end cut of the jacket, wherein the blocking device includes a film and a clamp to create a pocket for receiving the blocking material. A further blocking device is positioned over the window cut wherein the optical fibers are expanded relative to the jacket by pushing the jacket ends toward one another and rotating relative to one another. The blocking material surrounds both ends of the jacket and the bowed outward optical fibers. A further blocking device includes a tube, two end caps, and two clamps for creating a pocket over a window cut which receives blocking material. Rollable ribbon cable is disclosed.

Description

BLOCKING FOR FIBER OPTIC CABLE

Cross-Reference to Related Application

This application is being filed on February 18, 2021 as a PCT International Patent Application and claims the benefit of U.S. Patent Application Serial No. 62/978,150, filed on February 18, 2020, the disclosure of which is incorporated herein by reference in its entirety.

Background

Fiber optic cables carry optical fibers used to transmit optical signals between providers and subscribers. Typically, large cables, such as trunk cables or “main” cables, carry a large number of fibers. The fibers of the main cable are spliced, split, optically connected to other fibers (e.g., via fiber optic connectors), or otherwise managed and routed to a desired destination, (e.g., a subscriber building). Due to the large number of fibers that need to be managed and routed, the main cable is often terminated in a fiber optic splice closure. Such fiber optic splice closures typically include an outer ruggedized and sealable shell defining an interior volume and one or more sealable ports for sealed cable entry to the interior. The closures can be adapted for outdoor or indoor use. The interior volume of a splice closure typically houses structures and equipment, such as splice trays to organize and route fibers to facilitate both storing of fibers and routing of fibers to their desired destinations.

The fibers of the cables that enter the closures can come in different forms, such as loose fibers or ribbonized fibers. Groups of loose fibers, e.g., groups of 12 loose fibers, or axial portions thereof, can be housed in protective tubes. Ribbonized fibers (or a fiber ribbon) includes a plurality of fibers, e.g., 12 fibers, bonded together. The fibers of the ribbon can be bonded side by side along their axial lengths to form a flat ribbon, or bonded at intervals along their axial lengths to form a Tollable ribbon of fibers or a Tollable fiber ribbon. Example Tollable fiber ribbons include the AccuRiser™ and AccuFlex® Tollable ribbon cables by OFS Fitel, LLC, Norcross, Georgia, U.S. A.

In telecommunications cables and closures exposed to the environment there is a need for blocking of water and/or gas from entering the closure through an interior of the cable and into the closure. There is a need for adding blocking material to prevent water or gas from passing through the cable and into the closure.

Summary

A device and method is provided for sealing an interior of a cable wherein a wrap is positioned at an end of a jacket of a cable wherein optical fibers extend past the wrap. The wrap may include an outer layer which covers the end of the jacket. An inner woven layer may optionally be provided. A fixation device can be mounted around the outer layer. A blocking material can be poured into the end of the jacket and the pocket defined by the wrap. Such an arrangement is useful for sealing a cable, such as a Tollable ribbon cable, and wherein the seal area can be positioned inside of a closure and the cable can be fixed to the closure. This arrangement may be useful inside a closure.

A device and method is provided for sealing an interior of cable includes making a window cut and creating two ends of a jacket with fibers extending therebetween. In one example, the fibers are expanded from a linear orientation to a bowed outward orientation by pushing the two cable ends together and also applying a twist. Grease can be added if desired into each of the jacket ends. A housing structure can be mounted around the bowed outward fibers so as to seal the cable jacket interior. A blocking material can be poured into the housing structure, around both ends of the jacket and the bowed outward fibers. This arrangement may be useful outside a closure.

A device and method is provided for sealing an interior of a cable includes making a window cut and creating two ends of a jacket with fibers extending therebetween. A tube is placed over the window cut, end caps are inserted into the tube and clamps are mounted around the tube to clamp the tube and the caps to the cable. A blocking material can be poured into the housing structure, around both ends of the jacket and the exposed fibers. This arrangement may be useful outside a closure.

Brief Description of the Drawings

FIG. 1 shows an example cable with an end cut for use with a blocking device;

FIG. 2 is a cross-sectional view of the cable of FIG. 1;

FIG. 3 is a schematic view of a handhole including a cable and a closure;

FIG. 4 shows the elements of a blocking device and the cable before assembly; FIG. 5 shows the cable of FIG. 1 including a woven material over an end of the cable jacket;

FIG. 6 shows a step of adding a tape or film;

FIG. 7 shows the tape wrapped around the woven material and a part of the jacket;

FIG. 8 shows a strap wrapped around the tape;

FIG. 9 shows a mounting block for tightening the strap around the tape;

FIG. 10 shows the completed step of a tightened strap with the mounting block in position around the end of the cable jacket;

FIG. 11 shows the application of the flowable blocking material at the end of the cable jacket where the optical fibers extend past;

FIG. 12 shows the optical fibers surrounded by cured blocking material outside of the woven material and the tape (removed);

FIG. 13 shows an alternative blocking device located outside of the closure within a handhole;

FIG. 14 shows a cable like the cable of FIG. 1, including a window cut defining two ends of the jacket;

FIG. 15 illustrates a step where the ends of the cable jacket are moved toward one another and rotated relative to one another creating a bowed outward portion of optical fibers;

FIG. 16 shows the application of grease to one end of the cable jacket;

FIG. 17 illustrates a schematic view of the blocking device positioned over the window cut of the cable;

FIG. 18 shows a fixture for holding the cable of FIG. 15 in the bowed outward orientation;

FIG. 19 shows a bottom portion of the closure for holding the fixture and the cable of FIG. 18;

FIG. 20 shows the closure of FIG. 19 fully closed, and available for receiving the blocking material around the ends of the cable jacket and the exposed optical fibers;

FIG. 21 shows an alternative closure in an open position with the cable including the bowed outward fibers;

FIG. 22 shows the closure of FIG. 21, in a closed position ready for the application of the blocking material; FIG. 23 shows a cable including a tubular blocking device kit;

FIG. 24 shows a completed blocking device over the cable;

FIG. 25 shows a schematic view of the blocking device of FIG. 24 for holding blocking material around a window cut of a cable;

FIG. 26 shows the cable of FIG. 24 during processing, including a window cut with two jacket ends;

FIG. 27 shows a tube relative to the cable with the window cut, before the tube is positioned over the window cut;

FIG. 28 shows the tube, two clamps, and two end caps;

FIG. 29 shows one end cap, one clamp and one end of the tube being ready to be slid over the cable;

FIG. 30 shows a further step in the process where one end cap and the tube clamps are being slid over the window cut;

FIG. 31 shows the clamps, the end caps and the tube in the final position, with one end cap being slid into the end of the tube;

FIG. 32 shows the blocking device in position over the cable; and

FIG. 33 shows the application of the blocking material to an interior of the tube.

Detailed Description

Referring now to FIGS. 1 and 2, and example cable 10 is shown. In this example, a Tollable ribbon cable 10 is shown. Cable 10 has an end cut wherein optical fibers 16 extend past the end 20 of an outer jacket 14 that has been cut away.

The example cable 10 is a 432 cable with an outside diameter of 11.5 millimeters. Water blocking tape 12 is located inside the cable jacket 14. Inside of the water blocking tape 12 are six bundles (marked by a color fabric wire) each containing six ribbon bundles of each twelve fibers 16, totaling 432 fibers.

Aramid yarn 18 is embedded in the cable jacket 14. In this particular cable, there are no rigid strength members in the middle of the cable. In the case of reliable ribbon cable, and maybe other cables, the fiber optic cables may be densely packed inside a cable jacket. While the cable is densely packed, there is still an opportunity for water or gas to enter the cable and travel through the cable and into the closure. Because of a cable construction, whether densely packed or not, there is a need for devices and methods for allowing the addition of effective blocking material. Referring now to FIG. 3, the cable 10 enters a handhole 22 and extends to a closure 24. In this arrangement, it is desirable to provide blocking to the cable inside of the closure. The cable 10 is brought all the way to the closure and then the blocking feature is added to the cable and maintained within the interior of the closure 24.

Referring now to FIGS. 4-12, a blocking arrangement inside the closure is shown in one example. A tape 30 and a woven material 32 is utilized with flowable blocking material 36 at the end of the cable jacket 14. Referring to FIG. 5, a woven material 32 is positioned around the cable jacket 14 at an end of the cable jacket 14 where the fibers extend past the end of the jacket. The woven material 32 is used for strength between the blocking compound and the cable. Referring now to FIG. 6, the tape or film 30 is wrapped around the cable and the woven material 32. The tape 30 is placed around the able up to the jacket end then the plastic will be approximately past the cable jacket end. In one example, two centimeters of tape 30 extends past the end of the jacket. This is illustrated in FIG. 7.

Referring now to FIGS. 8-10, a cable attachment device 46 is shown. In FIG. 8, a strap 42 is wrapped around the tape 30 and the woven material 32. A mounting block 44 tightens the strap 42 around the cable, the woven material, and the tape. The strap 42 is useful when the cable is pressurized for testing, the blocking will not move, and additionally the cable is now fixed for cable fixation. Cable fixation device 46 can be made in accordance with the devices and used in the methods of US Patent 10379310, the disclosure of which is hereby incorporated by reference.

Referring now to FIG. 11, the blocking compound or material 36, such as a two part epoxy, is inserted in between the fibers with a nozzle 48. The blocking compound will first flow between the ribbons and the cable jacket. Once it cannot go deeper into the cable, the blocking compound will raise up and can be filled up to the end 34 of the tape 30. Once the blocking material 36 is cured, the end of the cable jacket is sealed from water and/or gas.

In the illustrated example in FIGS. 4-12, a blocking device 26 is formed by a wrap (film 30, and optionally woven material 32), strap 42, and blocking material 36.

Referring now to FIG. 13, a blocking device 50 is shown outside of closure 24. When the blocking device 50 is outside of closure 24, a window cut is needed in the cable where the blocking compound will be added. This area will be protected again by blocking device 50 including a closure arrangement. The cable will continue into the closure 24. The cable 10 will go into the closure and can be fixed in known manners. No extra length of cable is needed inside the closure for the blocking device.

FIG. 14 shows a window cut of the cable wherein the fibers are exposed between two ends 52 and 54 of cable jacket 14. Without further action, the fibers are very densely packed and it is not easy to apply water blocking in between the fibers. However, by applying a twist and a push to the cable, the fibers can spread out as shown in FIG. 15 without causing damage to the fibers. In one example, cable portion 64 is fixed. Cable portion 62 is rotated, such as one half to three quarters of a turn and then cable portion 62 is moved toward cable portion 64 resulting in the expanded shape or bowed outward shape of the fibers 65 shown in FIG. 15. At that time, ends 62 and 64 are held fixed for further processing. Again as shown in FIG. 14, the fibers are densely packed and it is not easy for applying the water blocking material in between the fibers. By creating the shape of FIG. 15, there is room to inject grease with a grease applicator 60 into cable portions 62 and 64 as shown in FIG. 16 for example. Grease is optional in some examples. FIG. 17 shows that the grease fills the micro paths in each cable portion 62 and 64 and a water blocking material is applied over the portion of the cable where the jacket has been removed.

Referring now to FIGS. 18-20, a first closure 66 is shown for providing a sealed interior for covering the exposed window cut with a flowable blocking material 36. Material 36 is injectable into the closure 66 through a port. A fixture 68 holds the cable in the position shown in FIG. 15. FIGS. 21 and 22 provide an alternative design for a second closure 69 covering the window cut with a flowable blocking material, fillable through a port.. Once the blocking material 36 is cured, the end of the cable jacket is sealed from water and/or gas.

As shown in FIG. 23, a blocking device 90 in the form of a tubular kit can be provided including two caps 70, two hose clamps 72, a cable attachment 74 in the form of a tube 74 and a blocking material 76 for use with cable 10. Again a window cut is made in the cable and caps 70 are provided on each end 62, 64 of cable 10. The hose clamps secure the cable attachment so that the caps and cable attachment remain in place over the exposed fibers. A small opening 80 is provided to inject the blocking material 76 into the void provided by caps 70 and tube 74.

FIG. 24 shows a completed blocking device 90 over the cable 10. FIG. 25 shows a schematic view of the blocking device 90 of FIG. 24 for holding blocking material 76 around a window cut of a cable. FIG. 26 shows the window cut between ends 52, 54 of cable jacket 14 of cable 10 exposing fibers 18. FIG. 27 shows a tube relative to the cable with the window cut, before the tube is positioned over the window cut. FIG. 27 also shows marks 67 on the cable to allow for centering of tube 74 over the exposed fibers.

In FIGS. 28-31, one cap 70 and the one hose clamp 72 on the tube are slid over the cable to the alignment mark. FIG. 28 shows the tube 74, two clamps 72, and two end caps 70. FIG. 29 shows one end cap, one clamp and one end of the tube 74 being ready to be slid over the cable 10. FIG. 30 shows a further step in the process where one end cap 70 and the tube clamps 72 with the tube 74 are being slid over the window cut.

The second cap 70 and the second hose clamp 72 are then positioned as shown in FIG. 31.

Hose clamps are tightened to secure tube 74 in place as shown in FIGS. 32 and 33. The blocking compound is then added within the tube 74.

End caps 70 include an inner portion 71 inserted within tube 74 and over the cable jacket adjacent each end 52, 54, and also radially under each clamp 72. Caps 70 also include an outer lip 75 that is positioned over each end of tube 74. The blocking device 90 may be useful for cables of different diameters. In some examples the fibers extending between the jacket ends may have a bowed outward orientation for the optical fibers to improve sealing by the blocking material.

The methods defined herein can comprise applying the flowable blocking material to the two ends of the jacket and/or the exposed optical fibers with an applicator, such as a brush. In the case of device 50 for example, the brush can be used to apply blocking material 36 in and around area 100 for increased coverage of the material around the fibers and/or the jacket ends. The brushing step can be in addition to injecting the blocking material into a housing or tube or other structure around the fibers and jacket ends.

The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.

Claims

What is claimed is:

1. A telecommunications cable with a blocking arrangement comprising: a fiber optic cable including a jacket with an end cut, the end cut defining an end of the jacket, and optical fibers within the cable jacket and extending beyond the end of the jacket; a wrap around the end of the jacket including a tape which extends beyond the end of the jacket; a blocking material extending into the cable at the end of the jacket, and extending past the end of the jacket inside of the wrap.

2. The cable of claim 1, wherein the wrap comprises an outer tape layer, and an inner woven layer.

3. The cable of claims 1 and 2, further comprising a clamp around the cable jacket adjacent to the end of the cable jacket.

4. A telecommunications cable with a blocking arrangement comprising: a fiber optic cable including a jacket with a window cut, including two ends of the jacket and exposed fibers between the two ends of the jacket; a plurality of fibers extending between the two ends of jacket having a bowed outward orientation for the optical fibers; a housing covering the two ends of the jacket and the bowed outward optical fibers; a blocking material within the housing and covering the two ends of the jacket and the bowed outward optical fibers.

5. The telecommunications cable of claim 4, further comprising a fixture for holding the cable in a bowed configuration within the housing.

6. A telecommunications cable with a blocking arrangement comprising: a fiber optic cable including a jacket with a window cut, including two ends of the jacket and exposed fibers between the two ends of the jacket; a tube having two ends; two end caps positioned at each end of the tube; two clamps positioned at each end of the tube and positioned wherein the end caps include an inner structure inside of the tube positioned radially inward from the location of the clamps and over the cable jacket; the tube including an opening for receipt of blocking material; a blocking material positioned within an interior of the tube covering both ends of the jacket and the exposed optical fibers.

7. A method of providing a blocking device to an optical fiber cable comprising: providing an optical fiber cable including an end cut of the jacket of the optical fiber cable, wherein the end cut defines an end of the jacket, and optical fibers extending past the end of the jacket; wrapping a tape around the end of the jacket wherein the tape is positioned on an exterior surface of the jacket, and wherein the tape extends over the fibers past the end of the jacket; positioning a clamp around the tape positioned over the jacket; tightening the clamp around the tape positioned over the jacket positioning flowable blocking material inside of the jacket around the optical fibers; positioning further flowable blocking material around the optical fibers which extend past an end of the jacket.

8. A method of providing a blocking device to an optical fiber cable comprising: providing an optical fiber cable including a window cut defining two ends of the jacket, with exposed optical fibers in between the two ends of the jacket; moving the two ends of the jacket relative to one another in an axial direction of the cable, and rotating the two ends of the jacket relative to one another about a longitudinal axis of the cable to create a bowed outward arrangement of exposed optical fibers; enclosing the two ends of the jacket and the bowed outward arrangement of exposed optical fibers in a housing; positioning flowable blocking material to cover the two ends of the jacket and the bowed outward arrangement of exposed optical fibers.

9. The method of claim 8, further comprising attaching the cable to a fixture to hold the bowed outward arrangement of the optical fibers.

10. A method of providing a blocking device to an optical fiber cable comprising: providing an optical fiber cable including a window cut defining two ends of the jacket, with exposed optical fibers in between the two ends of the jacket; positioning a tube with two end cap at each end of the tube wherein the end caps include an inner portion received within the tube, and positioning the tube over the window cut wherein the end caps are positioned on an exterior of the cable jacket; clamping the tube on each end of the tube to the cable wherein the inner portions of the end caps on each end of the tube are positioned radially inward from the clamps; positioning flowable blocking material in an interior of the tube over the two ends of the jacket and the exposed optical fibers.

11. The methods of claims 8-10, further comprising applying the flowable blocking material to the two ends of the jacket and/or the exposed optical fibers with an applicator, such as a brush.

12. The cables and methods of claims 1-11, wherein the fiber optic cable is a Tollable ribbon fiber optic cable.