Abstract:
In one aspect, a method to repair a cable jacket includes disposing a shrink tube on a damaged area of a cable jacket of a cable. The shrink tube includes a first end portion and a second end portion. The method also includes heating the shrink tube to seal the damaged area and tapering the first end portion of the shrink tube by cutting the shrink tube. Another aspect includes a device to taper end portions of a cable jacket shrink tube repair. A further aspect includes a device to dispose a tube on a cable.

Description:
BACKGROUND 
     Electric, optical or electro-optical cables are typically wrapped in a polymer jacket to protect internal conductors and/or optical fibers from damage. Cable jackets used in undersea applications can be damaged at anytime. In one example, cable jackets may be damaged during assembly. In another example, cable jackets may be damaged during deployment. In a further example, cable jackets may be damaged after deployment by marine life such as marine mammals, sharks, reef fishes, invertebrates and so forth. Also, cable jackets may be damaged during retrieval. Damage to the cable jacket can allow an undersea jacket to become flooded, potentially rendering the cable inoperable. 
     SUMMARY 
     In one aspect, a method to repair a cable jacket includes disposing a shrink tube on a damaged area of a cable jacket of a cable. The shrink tube includes a first end portion and a second end portion. The method also includes heating the shrink tube to seal the damaged area and tapering the first end portion of the shrink tube by cutting the shrink tube. 
     In another aspect, a device to taper end portions of a cable jacket shrink tube repair includes a first member including a first channel extending a long a longitudinal axis of the device, a second member including a second channel extending a long the longitudinal axis of the device and a fastening structure configured to fasten the first member and the second member together and to enable the device to be in an open position and a closed position. In the closed position, the first and second channels are configured to hold a first portion of a cable having a shrink tube and a second portion of the cable without the shrink tube. 
     In a further aspect, a device to dispose a tube on a cable includes an outer pipe and an inner pipe disposed within the outer pipe. The device is configured to receive a tube between the outer pipe and the inner pipe and to receive the cable through an interior of the inner pipe. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flowchart of an example of a process to repair a cable jacket. 
         FIG. 2A  is cutaway view of an installation tool holding a shrink tube. 
         FIG. 2B  is a view of the installation tool on a cable on reels. 
         FIG. 2C  is a view of the installation tool on the cable. 
         FIG. 2D  is a cutaway view of the installation tool of  FIG. 2C  without an inner pipe. 
         FIG. 3  is a flowchart of an example of a process to install the shrink tube onto the cable using the installation tool. 
         FIGS. 4A to 4D  are views of a tapering tool with the cable and a shrunken shrink tube. 
         FIG. 5  is a flowchart of an example of a process to taper a shrink tube. 
     
    
    
     DETAILED DESCRIPTION 
     Damaged cable jackets are expensive and time-consuming to repair by traditional molding methods. These methods typically require specialized facilities to affect repair. Often reels of damaged cable remain unused on shelves because it is too costly to repair them. For example, high cost (e.g., greater than $100K) subsea cables have been mothballed in significant numbers due to extensive deployment-related jacket damage. Described herein are low cost, fleet adaptable techniques and tools that will save time and money in repairing damaged cable jackets so that these sea cables may be brought into service. 
     Referring to  FIG. 1 , an example of a process to repair a cable jacket is a process  100 . The process  100  includes repairing cable jacket damage by using heat shrinkable tubing (referred to herein as a “shrink tube”) lined with a thermoplastic adhesive to cover the damaged area. In one example, the shrink tube is, prior to heating, a 2-inch nominal inner diameter shrink tube made of polyolefin. In one example, the shrink tube has a shrink/recovery ratio of about eight-to-one. That is, when the shrink tube is heated, its diameter shrinks eight times less than its original size. In one particular example, the shrink tube is a URHT-200 shrink tube manufactured by TYCO ELECTRONICS®/RAYCHEM®. In one example, the shrink tube includes a pre-coated interior lining of thermoplastic adhesive (e.g., a hot melt adhesive). In one particular example, the adhesive is a S1030 hot melt adhesive manufactured by RAYCHEM®. In another example, wraps of S1030 hot melt adhesive tape may be applied to the cable and unlined shrink tube placed over the tape. After applying heat to the adhesive and the shrink tube, the shrink tube originally a nominal 2 inches in inner diameter can be shrunk down to a nominal 0.25-inch inner diameter (or roughly the diameter of a cable) to produce a durable, waterproof sleeving patch capable of withstanding the harsh conditions of a deep sea environment. The eight-to-one shrink ratio is used, in this example, to accommodate connectors and other obstacles on the ends or along the length of the cable, without disassembly or removal of the obstacles. In one example, the URHT-200 shrink tube will pass over a 1.85-inch outside diameter connector at the end of the cable and over numerous 1.25-inch outside diameter in-line obstacles (swellings or bulges containing sensors/hydrophones) along the length of the cable. One of ordinary skill in the art would recognize that other shrink ratios may be considered for dimensionally different cables and cable obstacles. 
     Cable is inspected and cable jacket damage is identified ( 102 ). The amount of shrink tube required for the cable jack repair is determined ( 108 ) and allocated ( 116 ). For example, for each damaged jacket area identified, an amount of shrink tube is determined and allocated for the cable jacket repair. For each cable jacket damaged area, a section of the shrink tube is disposed onto the cable ( 124 ). For example, for each damaged area of the cable jacket an allocated amount of shrink tube is provided. The shrink tube is heated ( 132 ). For example, hot air (e.g., from a heat gun, heating blanket or manifold) is applied to the shrink tube. In one example, the temperature of the hot air is about 220° C. The shrink tube reduces in size, melts the adhesive and seals the damaged cable jacket area. The end portions of the shrink tube are tapered ( 140 ) to facilitate smooth transition through fairleads and sheaves during cable launch and retrieval. Tapering is necessary due to the exceptionally thick resultant unexpanded/recovered wall dimension initially required to produce an eight-to-1 ratio shrink tube. It is determined if any damaged cable jacket areas remain ( 142 ). If so processing blocks  124 ,  132 ,  140  and  142  are repeated. 
     Referring to  FIG. 2A , an installation tool  200  may be used to dispose shrink tube onto the cable. The installation tool  200  allows for the shrink tube to be deposited onto cable in order to reduce the introduction of any contaminants. In one example, the installation tool  200  includes an outer pipe  202  and an inner pipe  212  which together loosely hold the shrink tube  208  when loaded into the installation tool  200 . The outer pipe  202  and the inner pipe  212  are held together by an end cap  216 . The outer pipe  202  provides a rigid structure for handling/fixture of the installation tool  200 . In one example, the outer pipe  202  has a 2.5 inch inner diameter, a 0.06 inch wall thickness and is about 36 inches long. 
     The outer pipe  202  also includes perforations  218   a - 218   d  ( FIG. 2C ). In one example, the perforations  218   a - 218   d  are each about 8 inches long. The inner pipe  212  prevents cable jacket contaminants from contacting an inner surface of the shrink tube  208 . In one example, the inner pipe  212  includes a 2-inch outer diameter, a 0.06-inch wall thickness and is about 36 inches long. In one example, the installation tool  200  is about 38 inches long. 
     Referring to  FIGS. 2B to 2D , in one example, an end of the cable  250  is passed through the installation tool  100 . The cable  250  is rolled from one reel  220   b  to another reel  220   a  so that the cable passes through the center of the installation tool  200 . For example, the reels  220   a ,  220   b  are turned in a rotational direction X and the cable  250  correspondingly moves from the reel  220   b  to the reel  220   a  in a direction Y. In some examples, the cable  250  includes inline obstructions  262  represented by swellings or bulges in the cable at connector or sensor locations. 
     Cable jacket damage is repaired by placing a section of the shrink tube  208  in the installation tool  200  onto to the cable  250  at the damaged area. In one example, the shrink tube  208  is precut into sections  208   a - 208   l  prior to being loaded into the installation tool  200 . In another example, the shrink tube is cut (e.g., using a sonic cutter or other cutter integrated with the installation tool  200 ) just prior to the shrink tube sections  208   a - 208   l  being removed from the installation tool  200  to be placed over the damaged portion of the cable jacket. The perforations  218   a - 218   d  allow the user to slide out shrink tube sections  208   a - 208   l  out an end  222  of the installation tool  200 . 
     Referring to  FIG. 3 , one example of a process to dispose the shrink tube  208  onto the cable  250  using the installation tool  200  is a process  300 . In one example, the cable  250  is first inspected end-to-end for damage prior to repair. The location and length of damage is recorded. The initial inspection of the cable determines the length of shrink tube tubing required to repair each respective damage site. The shrink tube  208  is loaded in the installation tool  200  ( 304 ) via the open end of the tool in pre-cut segments with length and respective serial order defined by the initial inspection. In another example, the installation tool  200  disposes shrink tube segments cut to length by an integrated cutter (not shown). The integrated cutter allows cable inspection and repair to be concurrent activities. As cable damage is encountered an appropriate length of tubing is cut to order. The installation tool  200  with the integrated cutter is loaded with a continuous length of shrink tube  208 . The length of continuous tubing corresponds to the axial capacity of the installation tool  200  (e.g., an installation tool  200  with 36-inch pipes can accommodate a 36-inch segment of tubing). The cable  250  is fed through the installation tool  200  stopping just after a damage site passes out the tail end of the tool. The shrink tube segments are accessed via the longitudinal perforation in the outer pipe  202  and slid out the open end of installation tool  200  onto the damaged cable jacket area ( 308 ). 
     Referring to  FIGS. 4A to 4D , an example of a tool to taper the shrink tube  208  after the shrink tube has been heated, for example, is a taper tool  400 . The taper tool  400  includes a first member  402 , a second member  404  and hinges  406  coupling the first member to the second member. The first member  402  and the second member  404  each include a channel  422 . The taper tool also includes a razor blade  408 . For simplicity, the razor blade  408  is in an exploded view from the rest of the taper tool  400  as will be further described. The channel  422  includes a first section  422   a , a second section  422   b  and a third section  422   c . The first section has a width, W 1 , and the third section  422   c  has a width, W 2 , which is smaller than the width, W 1 . In one example, W 1  is 0.62 inches and W 2  is 0.28 inches and the cable  250  is a 0.25-inch-diameter cable. The second section  422   b  is between the first section  422   a  and the third section  422   c  and thus the length of the second section tapers from the width, W 1  to the width, W 2 . One of ordinary skill in the art would recognize that the tool dimensions can be altered to accommodate cables of other diameters. The first section  422   a  and the second section  422   b  are configured to receive the cable  250  with the shrink tube  208  with the second section receiving an end portion  428  of the shrink tube  208 . The third section  422   c  is configured to receive the cable  250  without the shrink tube  208 . The second member  402  includes a slot aperture  430  for holding the razor blade  408  and angled in order to taper the end portion  428  of the shrink tube  208 . The first member  402  includes a gap  440  from which shrink tube parings/shavings are expelled. 
     Referring to  FIG. 5 , one example of a process to taper end portions of a shrink tube using the tapering tool  400  is a process  500 . The cable  250  with the shrink tube  208  is placed in the tapering tool  400  ( 502 ). For example, the cable  250  with the shrink tube  208  is placed in one of the channels  422  as shown in  FIGS. 4A to 4C . In particular, a portion of the cable  250  with the shrink tube  208  is placed in the first section  422   a  and the second section  422   b  with the second section receiving the end portion  428  of the shrink tube. A portion of the cable  250  without the shrink tube  208  is placed in the third section  422   c . The tapering tool  400  is closed ( 512 ). For example, the first member  402  and the second member  404  are place on top of each other as shown in  FIG. 4D  so that the channels  422  are aligned. The tapering tool  400  is rotated about the cable ( 522 ). In particular, the end portion  428  of the shrink tube  208  is in contact with a razor blade  408  in the slot aperture  430 . As the taper tool is rotated about the cable  250 , the razor blade  408  correspondingly rotates and slices away the shrink tube  208  to form a taper. In one example, the razor blade is a standard razor blades commonly used. It is determined if another end of the shrink tube  208  is left to taper ( 532 ). If so, processing blocks  502 ,  512 ,  522  and  532  are repeated. 
     The processes described herein are not limited to the specific embodiments described. For example, the processes  100 ,  300  and  500  are not limited to the specific processing order of  FIGS. 1 ,  3  and  5 , respectively. Rather, any of the processing blocks of  FIGS. 1 ,  3  and  5  may be re-ordered, combined or removed, performed in parallel or in serial, as necessary, to achieve the results set forth above. 
     Elements of different embodiments described herein may be combined to form other embodiments not specifically set forth above. Other embodiments not specifically described herein are also within the scope of the following claims.