WO1998021796A1 - Sealed closure with support core systems and methods - Google Patents

Sealed closure with support core systems and methods Download PDF

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Publication number
WO1998021796A1
WO1998021796A1 PCT/US1997/003440 US9703440W WO9821796A1 WO 1998021796 A1 WO1998021796 A1 WO 1998021796A1 US 9703440 W US9703440 W US 9703440W WO 9821796 A1 WO9821796 A1 WO 9821796A1
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WO
WIPO (PCT)
Prior art keywords
cable
support core
outer jacket
sealed closure
bondable material
Prior art date
Application number
PCT/US1997/003440
Other languages
French (fr)
Inventor
Thomas S. Croft
Armond D. Cosman
John Fulmer
Jerry Don Jackson
William G. Allen
Original Assignee
Minnesota Mining And Manufacturing Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minnesota Mining And Manufacturing Company filed Critical Minnesota Mining And Manufacturing Company
Priority to AU20682/97A priority Critical patent/AU2068297A/en
Publication of WO1998021796A1 publication Critical patent/WO1998021796A1/en

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Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02GINSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
    • H02G15/00Cable fittings
    • H02G15/013Sealing means for cable inlets
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02GINSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
    • H02G15/00Cable fittings
    • H02G15/08Cable junctions
    • H02G15/18Cable junctions protected by sleeves, e.g. for communication cable

Definitions

  • the present invention generally relates to sealed protective sleeves or closures for spliced or damaged sections of cables carrying electrical current or optic signals for a variety of applications, especially electronic and fiber optic signal carrying cables for telecommunications and computer networks, and, more particularly, to such closures comprising an elastomeric cover portion and a thermoplastic element that acts as a support core and, during installation, provides fluid material to seal around the protected part of the cable and form a bond between the inner surface of the elastomeric cover and the outer surface of the cable insulating cover.
  • the low surface energy outer jacket of these cables forms a protective sheath around the conductor elements
  • This low surface energy outer jacket serves as a barrier to contact of environmental conditions with the conductor elements If the integrity of the outer jacket of these cables is compromised, however, for example, by wear damage, removal to access the conductor elements, or other conditions, the outer jacket does not sufficiently seal the conductor elements from the environment As may be expected, the integrity of the cables, including their useful life expectancy, their operation, and their other characteristics, may be affected if the seal of the outer jacket is not repaired or replaced
  • Closures of this type are important because environmental conditions that contact the cables, particularly, the conductor elements, may damage the integrity, function, and useabi ty of the cables In many applications, it is, thus, imperative and desirable to seal the conductor elements of the cables to protect against environmental effects
  • Closures for cables have been particularly important in locations of cable splices and outer jacket deterioration
  • an outer covering or housing has been placed over portions of the cable in locations of exposed conductor elements, such as at splices and deteriorated sections
  • the covering or housing has then been sealed with the remaining outer jacket of the cables to seal the conductor elements within the covering or housing
  • the covering or housing has been sealed with the outer jacket by pressure, for example, by shrinking the covering or housing against the cable outer jacket, and/or by sealants, for example, by adhering the covering or housing to the cable outer jacket and/or expanding the sealant to fill voids between the covering or housing and outer jacket
  • heating has sometimes served to shrink the covering or housing or to adhese or expand the sealant
  • Various methods of heating the covering or housing and/or sealant, and, in some instances, the outer jacket have been employed to cause the covering or housing to seal against the outer jacket by pressure of the covering or housing due to shrinkage or of the sealant due to expansion or adhesion
  • the heating for these purposes has typically been either by resistive, inductive, external torch, or chemical process
  • resistive heating wires of high resistance are located in the vicinity of the desired heating Electrical current is fed to the wires, and the resistance of the wires generates heat The current may be varied to obtain the desired heat for the heating
  • electromagnetic elements are placed in the vicinity of the desired heating and a magnetic field is oscillated around the electromagnetic elements The electromagnetic elements in the magnetic field generate heat for the heating
  • the covering or housing of the sealed closure for example, if shrinkable, has, in certain cases, been supported by a structural core over which the covering or housing is placed in order that the cable may be placed within the structural core and, thus, also within the covering or housing. This has been necessary because the covering or housing, alone, is not easily stretched to place over the cable.
  • the structural core has been removed from around the cable and from within the covering or housing prior to shrinking the covering or housing to seal the covering or housing against the outer jacket of the cable.
  • the structural core, as removed from around the cable and from within the covering or housing is treated as refuse Once the structural core has been so removed, the covering or housing then contracts and, thus, achieves pressure sealing, as previously described
  • a problem with use of the structural core is that its removal requires extra steps in the sealed closure implementation process Also, the structural core, once removed, is refuse and must be properly disposed Even more, once the structural core is removed, the sealed closure is not rigid, which, for example, may be desirable when the closure is used to seal cable splices Furthermore, the structural core is not easily useable for cable that does not have a break in the cable near the desired location along the cable of the sealed closure With the structural core, the cable must be fed through the structural core and the structural core, together with the sealed closure supported thereby, must be passed along the cable to the desired location along the cable Such feeding of the cable through the structural core is not always practical, particularly in many field operations involving sealed closures
  • Embodiments of the present invention accordingly, provide systems and methods for sealed closure of cables using a support core.
  • the embodiments avoid problems of conventional cable seal techniques and provide advantages of improved sealing, ease of use, low cost, field-use simplicity, and other advantages
  • one embodiment of the invention is a kit for sealed closure of a cable of the type having a low surface energy outer jacket
  • the kit includes a support core capable of housing the cable and a bondable material, locatable between the support core and the outer jacket, for fusion bonding of the support core, the bondable material and the outer jacket The fusion bonding seals the cable with the support core
  • Another embodiment of the invention is a sealed closure for a cable of the type having a low surface energy outer jacket
  • the sealed closure includes a support core for housing the cable and a bondable material between the support core and the outer jacket of the cable The support core, the bondable material, and the outer jacket are fused, sealing the cable with the support core
  • Yet another embodiment of invention is a method for sealing closure of a cable having a low surface energy outer jacket.
  • the method includes the steps of housing the cable within a support core and bonding the support core to the cable
  • Another embodiment of the invention is a kit for sealed closure of a cable of the type having a low surface energy outer jacket
  • the kit includes a tubular support core having a longitudinal split to allow the tubular support core to be placed around the cable, a first bondable material locatable at the longitudinal split to allow the longitudinal split of the tubular support core to be re-joined, and a second bondable material, locatable between the support core and the outer jacket, for fusion bonding of the tubular support core, the bondable material, and the outer jacket
  • the fusion bonding seals the cable with the support core
  • a further embodiment of the invention is a sealed closure for a cable of the type having a low surface energy outer jacket
  • the sealed closure includes a tubular support core placed around the cable
  • the tubular support core has a longitudinal split.
  • the sealed closure also includes a first bondable material at the longitudinal split for re-joining the longitudinal split of the tubular support core and a second bondable material between the support core and the outer jacket of the cable The longitudinal split is re-joined by the first bondable material
  • the tubular support core, the second bondable material, and the outer jacket of the cable are fused This seals the cable with the support core
  • Another embodiment of the invention is a method for sealing closure of a cable having a low surface energy outer jacket
  • the method includes the steps of placing a tubular support core having a longitudinal split around the cable, rejoining the longitudinal split, and bonding the tubular support core to the cable
  • Yet another embodiment of the invention is a kit for sealed closure of a hole in a low surface energy outer jacket of a cable
  • the kit includes a polymer film for wrapping around the cable, over the hole and in the vicinity of the hole along the cable and a bondable material for placing over the polymer film Fusion bonding seals the polymer film and the bondable material with the outer jacket and the hole of the cable
  • Another embodiment of the invention is a sealed closure for repairing a hole in a low surface energy outer jacket of a cable
  • the sealed closure includes a polymer film around the cable, over the hole and in the vicinity of the hole along the outer jacket of the cable and a bondable material over the polymer film The polymer film and the bondable material are fused with the outer jacket and the hole of the cable
  • kits for sealed closure of a cable of the type having a low surface energy outer jacket includes a support core capable of housing the cable, a shrinkable tube capable of covering the support core, and a resistive wire locatable on the shrinkable tube Resistive heating fuses the support core and the shrinkable tube with the outer jacket of the cable, thereby sealing the cable with the support core
  • Another embodiment of the invention is a sealed closure for a cable having a low surface energy outer jacket
  • the sealed closure includes a support core for housing the cable, a shrinkable tube covering the support core, and a resistive wire wrapped around the shrinkable tube
  • the support core and the shrinkable tube are fused with the outer jacket of the cable by resistive heating via the resistive wire
  • Yet another embodiment of the invention is a method for sealed closure of a cable having a low surface energy outer jacket
  • the method includes the steps of housing the cable within a support core, wrapping a resistive wire around the support core, covering the support core with a shrinkable tube, and supplying current to the resistive wire to create heat
  • the support core and the shrinkable tube are fused with the outer jacket of the cable
  • FIG 1 is a perspective, partial cut-away, view of a closure apparatus with a cable (in phantom) extending therethrough, prior to bonding of the closure apparatus to an outer jacket of the cable, all according to embodiments of the present invention
  • Fig 2 is a perspective, partial cut-away, view of a sealed closure formed by the closure apparatus of Fig 1, upon bonding of the closure apparatus at its ends to the outer jacket of the cable, all according to embodiments of the present invention
  • Fig 3 is a flow diagram of a method for implementing the sealed closure of Fig 2, according to embodiments of the present invention
  • Fig 4 is a perspective view of a split closure apparatus according to embodiments of the present invention
  • Fig 5 is a perspective view of a sealed split closure formed by the split closure apparatus of Fig 4, upon bonding of the split of the split closure apparatus, all according to embodiments of the present invention
  • Fig 6 is a flow diagram of a method for implementing the sealed split closure of Fig 5, according to embodiments of the present invention
  • Fig 7 is a perspective, partial cut-away view, of a repair closure apparatus with a cable (in phantom) having a hole through the outer jacket to the conductor elements extending therethrough, prior to bonding of the repair closure apparatus to the outer jacket of the cable and to the hole and the conductor elements within the hole, all according to embodiments of the present invention
  • Fig 8 is a perspective, partial cut-away, view of a sealed repair closure formed by the repair closure apparatus of Fig 7, upon bonding of the repair closure apparatus along its entire length to the outer jacket, the hole, and the conductor elements within the hole of the cable, all according to embodiments of the present invention
  • Fig 9 is a perspective view of a polymer film and the binder of a shrink repair closure apparatus, each disposed over the hole in the outer jacket of the cable, wherein the hole exposes the conductor elements through the hole, according to embodiments of the present invention
  • Fig 10 is a perspective view of a heat shrink repair closure formed by bonding, from the shrink repair closure apparatus of Fig 9 which also includes a tape wrapped around the cable and over the hole, the polymer film, and the binder, according to embodiments of the present invention
  • Fig 1 1 is a flow diagram of a method for implementing the heat shrink repair closure of Fig 10, according to embodiments of the present invention
  • Fig 12 is a perspective view of a resistive sealed closure apparatus according to embodiments of the present invention.
  • the reference numeral 10 refers, generally, to a closure apparatus according to embodiments of the invention
  • the closure apparatus 10 comprises a support core 12
  • the support core 12 forms a hollow conduit 14 that extends longitudinally through the support core 12
  • the support core 12 is a unitary piece with an inner side 16 and an outer side 18
  • the hollow conduit 14 of the support core 12 is of sufficient size to accommodate a conventional cable 20
  • a communications or electrical cable having a conductor 20a and an outer jacket 20b shielding the conductor 20a from the environment
  • the cable 20 is shown spliced to a substantially identical cable within the hollow conduit 14 of the support core 12
  • the closure apparatus 10 also includes an environmentally resilient, shrinkable tube 24
  • the support core 12 is located concentrically within the shrinkable tube 24, and each of the support core 12 and the shrinkable tube 24 have approximately the same longitudinal length Between the support core 12 and the shrinkable tube 24, at each end thereof, is disposed a binder 22
  • the binder 22 is located in the vicinity of the outer jacket 20b when the closure apparatus 10, as shown in Fig 1, is located in place for sealing the conductor element 20a where not covered by the outer jacket 20b, also as shown in Fig 1
  • the binder 22 is not located in the vicinity between the ends of the support core 12 and the shrinkable tube 24 where the conductor elements 20a are not covered by the outer jacket 20b
  • the closure apparatus 10 when heated at its ends where the binder 22 is situated, collapses onto and joins with the outer jacket 20b at those ends to form the sealed closure 30
  • the support core 12, the binder 22, and the shrinkable tube 24 are fused with the outer jacket 20b of the cable 20 forming the fused ends 32
  • the shrinkable tube 24 with the support core 12 concentrically disposed therein are not collapsed onto the cable 20 and maintain substantially their original configuration as in the closure apparatus 10
  • the fused ends 32 seahngly enclose those portions of the conductor element 20a of the cable 20 not covered by the outer jacket 20b, along with portions of the outer jacket 20b of the cable 20 between the fused ends 32
  • the conductor elements 20a are sealed from the environment outside outer jacket 20b and the sealed closure 30
  • the sealed closure 30 provides permanent bonding to the low energy surface of the outer jacket 20b of the cable 20 at the fused ends 32, with a permanent air and water tight bond between the sealed closure 30 and the cable jacket 20b to prevent entry of environmental conditions into the sealed closure 30
  • the outer jacket 20b of the cable 20 is conventionally comprised of a polyethylene, polypropylene, or an inclusive copolymer and, in any event, is a low energy surface that serves as an electrical and environmental condition insulator
  • a variety of suitable materials may be employed for the closure apparatus 10, and, thus, comprise the sealed closure 30
  • the shrinkable tube 24 may be a tubular-shaped elastomeric material which is supported in a stretched condition on the support core 12
  • Certain pre-stretched tubes useable as the shrinkable tube 24 are disclosed, for example, in U.S Patent No 5,080,942 and U S Patent No 4,389,440, each assigned to the same assignee of the present invention and each incorporated herein by this reference
  • a suitable material for the shrinkable tube 24 is an elastomer, such as oil extended ethylene propylene diene monomers or ethylene propylene monomers (EPDM or EPM)
  • Other materials for the shrinkable tube 24 include compounded synthetic rubbers or other elastomers
  • the support core 12 supports the shrinkable tube 24 in a stretched condition
  • the support core 12 may be tubular-shaped and of outside diameter slightly less than the inner diameter of the shrinkable tube 24 in its stretched state
  • the support core 12 is formed of a material capable of maintaining the shrinkable tube 24 in a stretched state when the support core 12 is placed into the shrinkable tube 24
  • the material has a melting or softening temperature below the temperature which would affect the integrity of the shrinkable tube 24
  • a low melting point, low density polyethylene tube or pipe is suitable
  • a material which binds with the materials of the shrinkable tube 24, the support core 12, and the outer jacket 20b of the cable 20 at the softening or melting temperatures of the support core 12 is employed
  • An example of a binder 22 suitable for the sealed closure 30 is a composite material for induction bonding (also referred to as “electromagnetic bonding") as disclosed in U.S Patent Application Ser No 08/412,966, filed March 29, 1995, titled “Electromagnetic-Power-Absorbing Composite", assigned to the same assignee of the present invention and incorporated herein by this reference That patent application discloses, among other things, an electromagnetic-power-absorbing composite comprising a plurality of multilayered flakes dispersed in a binder agent
  • the binder agent is any of a variety of suitable polymers or polymer blends, such as thermoplastic polymers, thermoplastic elastomers, and thermally activated or accelerated cure polymers, or a polymeric or nonpolyme ⁇ c adhesive
  • the multilayered flakes may include at least one layer pair
  • the reference numeral 40 refers, generally, to a method for implementing the sealed closure 30, according to embodiments of the invention
  • the support core 12 is cut to an approp ⁇ ate length, such that the ends of the support core 12 overlap the outer jacket 20b adjacent the conductor elements 20a when the cable 20 is placed within the closure apparatus 10 and positioned therein as shown in Fig 1
  • the binder 22 is placed at the ends of the support core 12 over portions of the outer side 18 of the support core 12
  • the longitudinal length of the support core 12 over which the binder 22 is placed is less than the longitudinal length by which the outer jacket 20b of the cable 20 is positioned within the closure apparatus 10, as shown in Fig 1
  • the binder 22, in that placement on the outer side 18, is adhered, for example, by an adhesive, bonded, for example, by melting, or otherwise attached to the support core 12
  • the shrinkable tube 24 is stretched and placed over the support core 12 Once the support core 12 has been located within the shrinkable tube 24, the shrinkable tube 24 shrinks against the outer side 18 of the support core 12 and is supported by the support core 12 The binder 22 that is disposed at the ends of the support core 12 remains between the outer side 18 of the support core 12 and the shrinkable tube 24 at those ends
  • the cable 20 is positioned withm the support core 20 so that the conductor elements 20a of the cable 20 which are not covered by the outer jacket 20b of the cable 20 are maintained within the hollow conduit 14 formed by the support core 12
  • the conductor elements 20a are so positioned such that the binder 22 disposed at the ends of the support core 12 is in the vicinity of the outer jacket 20b
  • a step 50 the ends of the closure apparatus 10 in the vicinity of the outer jacket 20b are bonded to the outer jacket 20b at those locations
  • the step 50 of bonding the ends of the closure apparatus 10 to the outer jacket 20b seals the closure apparatus 10 with the outer jacket 20b, thereby forming the sealed closure 30
  • the bonding is achieved by heating the ends of the closure apparatus 10 to a temperature sufficient to melt the support core 12 and to cause the binder 22 to fuse the support core 12, the binder 22, and the shrinkable tube 24 with the outer jacket 20b of the cable 20
  • the shrinkable tube 24 provides uniform pressure to conform the support core 12 and the binder 22 around the outer jacket 20b to insure bonding
  • a field from a radio frequency power source (power of about 50 watts to about 100 watts, 102 MHz frequency) was used by placing the "tip antenna" over first one end and then the other end of the tube/PST unit above the susceptor composite binder strips This caused the flexible film insert part to melt and the end of the tube to collapse, allowing the PST to contract around the cable on each side of the splice and forming a sealing bond between the cable sheath and the PST material.
  • the shrinkable tube 24 rather than being placed over the entire longitudinal length of the support core 12, can be placed only at the ends of the support core 12 in the vicinity of the binder 22 A shrinkable tube 24 that extends over the entire length of the support core 12, however, can offer advantages of additional impact resistance in the area of the sealed closure 30 Even more, the binder 22 may additionally or alternatively be placed between the support core 12 and the outer jacket 20b of the cable 20
  • a plurality of support cores 12 could be employed The plurality of support cores 12 can provide a plurality of passages, extending from one end thereof to the other end thereof, for receiving a plurality of cables 20 or wires or splices of the cables 20 Such an arrangement can allow more complete bonding to the cable 20 or to insulation of individual wires or splices of wires, upon softening or melting of the plurality of support cores 12 In such an arrangement, individual or multiple wires or splices can be themselves sealed
  • the plurality of support cores 12, in such instance, can be of varied sizes to allow varied diameter- sized cables or wires to be disposed therein
  • one or more of the plurality of support cores 12 could be a solid that is an electromagnetic-power- absorbing composite, such as that previously mentioned and disclosed in the incorporated patents and patent applications
  • one or more additional supportive cores could be formed of such a composite having more or less of the electromagnetic-power-absorbing flakes than in the composite there disclosed or the various supportive cores may
  • the reference numeral 51 refers, generally, to a split closure apparatus according to embodiments of the invention
  • the split closure apparatus 50 like the closure apparatus 10 (shown in Fig 1), includes the support core 12 and the shrinkable tube 24
  • the shrinkable tube 24 is adhered to the outer side 18 of the support core 12
  • the support core 12 and the shrinkable tube 24, however, are split 52 along the longitudinal length thereof Diametrically opposite the split 52 along the longitudinal length of the inner side 16 of the support core 12, a channel 54, for example, a V-shaped channel, is formed partway through the support core 12
  • the channel 54 hingedly allows the split 52 to be opened by spreading respective portions of the support core 12 and the shrinkable tube 24 adjacent the split 52
  • the channel 54 is not necessary if the split 52 of the support core 12 can be suitably spread without it
  • longitudinal faces at the split 52 of the support core 12 and the shrinkable tube 24 are the inner faces 56 and the outer faces 58, respectively
  • the support core 12 includes a radio frequency antenna wire 60 that is embedded in and runs longitudinally
  • a binder agent that binds when subjected to an electromagnetic field in the GHz range such as that produced by a conventional microwave heater in a factory setting
  • an adhesive that maintains a bond in the presence of high temperature is useable
  • the split closure apparatus 51 forms a sealed split closure 61
  • the sealed split closure 61 is fused at the inner faces 56 adjacent the split 52 Bonding may be achieved by a binding material 62 disposed on the faces 56.
  • the binding material 62 may be an adhesive, a binding agent, a weld, or some other fusing mechanism
  • the electromagnetic-power-absorbing composite, previously described, is a suitable binding material 62 As the split 52 is fused, the sealed split closure 61 is tubular
  • the split closure apparatus 51 is particularly useful for forming the sealed split closure 61 in the field and in other circumstances
  • the cable 20, requiring sealing enclosure along its length because of an exposure of the conductor elements 20a outside the outer jacket 20b can not in certain instances be easily inserted through a tubular member, such as the closure apparatus 10, because an end of the cable 20 is not available
  • sealingly enclosing the conductor elements 20a may be achieved by enveloping the split closure apparatus 51 around the cable 20 in the vicinity of the conductor elements 20a so exposed
  • the reference numeral 70 refers, generally, to a method for implementing a sealed split closure 61 , according to embodiments of the invention
  • a step 72 the split 52 of the split closure apparatus 51 is widened by application of force to spread the inner faces 56 and the outer faces 58 adjacent the split 52 Spreading of the faces 56 and 58 causes the channel 54 to hingedly widen
  • a step 74 the cable 20 is, along its length, passed through the split 52 to within the support core 12
  • the split closure apparatus 51 is then positioned in the vicinity of the conductor elements 20 to be sealed
  • a step 78 once the cable 20 is passed through the split 52, the inner faces
  • the split closure apparatus 51 is then maintained with the faces 56 and 58 so abutting, for example, by a clamp, tape, adhesive, or some other binding mechanism which may be internal or external to the split closure apparatus 51 or otherwise
  • the split 52 of the split closure apparatus 51 is bonded If necessary for the bonding of the split 52, the binding material 62, for example, the electromagnetic-power-absorbing composite previously described or the others described, is disposed on the inner faces 56 adjacent the split 52 prior to the step 78.
  • the radio frequency antenna wire 60 is exposed to an oscillating electromagnetic field, for example, in the manner previously described. The oscillating electromagnetic field, acting on the antenna wire, thereby causes the binding material 62 to bond the faces 56 together.
  • the split 52 is bondable by resistive heating, either with or without binding material 62, by a bead of suitable adhesive, or otherwise.
  • the radio frequency antenna wire 60 (Figs 4-5) is replaced with a resistive wire, for example, a stainless steel, nickel chromium, or other suitably resistive material, that is embedded in and runs longitudinally through the wall of the support core 12 adjacent the split 52 or the resistive wire is otherwise placed in the vicinity of the faces 56 at the split 52
  • binding material 62 for example, polyethylene or Engage TM material, may be disposed at the faces 56
  • the resistive wire is located at or between the faces 56
  • One or more lengths of resistive wire may be so located Bonding of the split 52 of the split closure apparatus 51 is achieved by supplying an alternating current (AC) or direct current (DC) to the resistive wire The wire generates
  • the bonding step 50 provides a sealed closure similar to the sealed closure 30 (shown in Fig. 2)
  • An example of the method 70 follows: A susceptor composite binding strip (as described in an earlier example) bondable at a high frequency (about 1 to 3 GHz) (0 5" x 6.0" x 0 028") was heat- staked lengthwise to a polyethylene tube (1 65" OD, 6 0" long, 0 19" wall thickness) and then a 3M 463 I S Pull-N-Shrink (PST) tube (0 68" unstretched ID) was collapsed onto the tube The tube/PST unit was heated in a conventional microwave oven (approximately 1 GHz to approximately 3 GHz) for five (5) minutes, so that the tube was bonded to the PST
  • the tube/PST unit was split lengthwise in the region of the susceptor composite binding strip
  • the diametrically opposite side of the inner wall of the tube was notched with a lengthwise V-channel to create a hinge for the closure
  • the split seam of the tube was notched on both sides of the cut surface to allow for installation of a radio frequency antenna wire (tinned copper tubular braid, approximately 22 awg)
  • the antenna wire was run embedded in the tube wall longitudinally along each side adjacent the cut surface
  • a strip of susceptor composite material bondable at a lower frequency than the strip for bonding the PST to the polyethylene tube binder strip (6 0" x 0 15" x 0.016") was heat-staked to the cut mating surfaces between the two sides of the split seam.
  • the split seam in the tube/PST unit was forced together using a vise
  • the split seam was then permanently bonded together using a field from a radio frequency power source (50 MHz, 75 W, two minutes)
  • a 0.50" OD cable (HDPE sheath, aluminum shield, copper conductors) was run through the tube (the cable sheath and shield were cut in the center of the cable to allow for pressure check)
  • Each end of the tube/PST unit was prepared by spiraling susceptor strips and low density polyethylene (LPDE) strips around the cable until the air gap between the cable and closure wall was filled
  • the susceptor strips were 0.25" wide and the LDPE strips were 0 75" wide
  • the ends of the closure were sealed individually by applying an oscillating magnetic field from a radio frequency power source (95 MHz, 75 W) through a 3/4" stainless steel braided antenna loop for about 8-9 minutes This melted the end filler material and softened the ends of the tube/PST unit so that the ends collapsed onto the cable in the heating zone area After cooling, the ends of the cable were capped and the closure was flash tested in one foot of water at 10 psi for 10 minutes with no visible air bubbles
  • the shrinkable tube 24 is not employed with the split closure apparatus
  • a polyethylene tube with susceptor composite binder strip at its ends was prepared according to the immediately preceding example No Pull-N-Shrink tube (PST) was attached to the tube The split of the tube was resealed and the ends were prepared as also described in that example The ends of the tube were double- wrapped with a tape. Two different 2" wide tapes were employed in separate tests A first tape was a double rubber tape (Plymouth DR Rubber Tape, spec 6863, TL- 192, cat.
  • the reference numeral 90 refers, generally, to a repair closure apparatus, according to embodiments of the present invention
  • the repair closure apparatus 90 is substantially similar to the closure apparatus 10 of Fig 1, except that the binder 22 extends entirely along the outer side 18 of the support core 12 between the support core 12 and the shrinkable tube 24
  • the cable 20 (in phantom) exhibits a hole 20c (rather than a splice, as was shown in Fig. 1) in which the conductor elements 20a are exposed through the outer jacket 20b of the cable 20.
  • the repair closure apparatus 90 when heated along its length where the binder 22 is situated, collapses onto and joins, all along its length, with the outer jacket 20b and with the hole 20c and the conductor elements 20a exposed through the hole 20c.
  • the reference numeral 100 in Fig 8 refers, generally, to a repair sealed closure 100 Referring back to Fig 3, a method of implementing the repair sealed closure
  • 100 is identical to the method 40 of Fig 3 and as described herein, except that the entire length of the repair closure apparatus is bonded to the outer jacket 20b of the cable to cover and fill the hole 20c
  • a 100 pair telecommunication cable (10042 SEALPIC), approximately 16 inches long, had a 1/4" diameter hole drilled through the sheath exposing the individual wire pairs
  • An assembly was prepared by tacking (with a soldering gun) a susceptor composite binder strip (a 0 015 inch thick low density polyethylene strip - 5 1/4 inches long and 3 inches wide - containing 5% susceptor composite flakes) (J226-2 experimental production run)) on the outside of a 1 1/4" diameter polyethylene pipe (0 135 inch wall thickness)
  • the pipe with tacked susceptor composite binder strip was then used as a supporting core for a 3M 4630 S Pull-N- Shrink prestretched (PST) tube.
  • the PST tube and supporting core was then slid over the cable and positioned over the drilled hole in the cable
  • a field from a radio frequency power source (95 watt power at 102 8 MHz frequency) was generated by moving the "tip" from the lengthwise center of the PST tube and supporting core to each end thereof. This generated heat to soften the supporting core and allow the PST tube to contract around and seal the supporting core and PST tube in and over the hole and to bond the elastomeric material of the PST tube to the sheath of the cable
  • the reference numeral 1 10 refers, generally, to a shrink repair closure apparatus
  • the shrink repair closure apparatus 1 10 is comprised of a polymer film 1 1 1 (shown in phantom) that is wrapped around the cable 20, over the hole 20c in the outer jacket 20b of the cable 20 in which the conductor elements 20a are exposed
  • the polymer film 1 1 1 is, for example, the same material previously described herein for the support core 20 (shown in Fig 1), such as a low density polyethylene film
  • the binder 22 is disposed around the polymer film 1 1 disposed the binder 22
  • the shrink repair closure apparatus 1 10 forms a heat shrink repair closure 120 upon bonding of the tape 122, the binder 22, and the polymer film 1 1 1 to the outer jacket 20b, the hole 20c, and the conductor elements 20a of the cable 20
  • the numeral 130 refers, generally, to a method of implementing the heat shrink repair closure 120
  • a step 132 the polymer film 1 1 1 is wrapped around the cable 20 to cover the hole 20a
  • the binder 22 is placed on the polymer film 1 1 1 around the cable 20
  • the tape 122 is wrapped around the binder 22 and, thus, the cable 20
  • a step 138 the tape 122, the binder 22, and the polymer film 1 11 are sealingly bonded to the outer jacket 20b, the hole 20c, and the conductor elements 20a of the cable 20
  • An example of the method follows A cable having a hole through the sheath, exposing the conductive wires was wrapped with a piece of low density polyethylene film (1 inch wide, 2 inches long, 0 04 inch thickness) to cover the hole in the cable A susceptor composite binder strip (1 inch wide, 2 inches long) was then wrapped around the cable atop the polyethylene film The film and the binder strip were held in place
  • a field from a radio frequency power source (1 1 1 MHz frequency) was then used, as has been previously described in the examples herein, to melt the polyethylene film and the binder strip to fill and seal the hole in the cable and to bond the EPR tape to the sheath insulation
  • the cable was equipped as previously described in examples herein and then pressurized with 15 psi and placed in a water tank The cable remained pressurized for seven (7) days with no leakage detected. Hand pressure could not remove the tape
  • the repair closure apparatus 90 is employable to form the repair sealed closure 100 for a coaxial cable as the cable 20
  • the repair sealed closure 100 in the case of use with a coaxial cable as the cable 20, forms a suitable closure for splices, holes, or other conditions that expose the coaxial conductor elements along the coaxial cable.
  • the method 40 of implementing the repair sealed closure 100 is also applicable in the case of coaxial cable.
  • the closure apparatus 10 is also employable to form the sealed closure 30 for a coaxial cable as the cable 20.
  • the method 40 is applicable for implementing the sealed closure 30 for coaxial cable.
  • the sealed closure 30 is, furthermore, particularly useful for a combined coaxial/telecommunication buried service wire cable, where the buried service wire cables are spliced with 3M Discrete Connectors and the coaxial cables are spliced with coaxial cable connectors.
  • an assembly was prepared by tacking (with a soldering iron) a susceptor composite binder strip (a 0.015 inch thick low density polyethylene film - six inches long and three inches wide - containing 5% susceptor composite flakes (J226-2 experimental production run)) on the outside of a six inch length of polyethylene pipe (0.135 inch wall thickness, one and one quarter inch diameter) which was then placed within a 3M 3628S Pull-N-Shrink tube (PST) as a supporting core.
  • a susceptor composite binder strip a 0.015 inch thick low density polyethylene film - six inches long and three inches wide - containing 5% susceptor composite flakes (J226-2 experimental production run)
  • the assembly was slid over a metallic RG-1 1 coax cable connection made from the 0.3815 inch diameter coax cable stripped away from a combined coaxial/buried service wire cable (Superior Cable 05/95 3 x 22 BSW - NSF 1 1/60% cable).
  • a field from a radio frequency power source 75-100 watts power at 95-100 MHz frequency
  • an assembly was prepared by tacking a five and three quarter by twelve inch low density polyethylene film (0.0425 inch thickness) to an approximately same size piece of susceptor composite binder strip.
  • the binder strip was rolled up two and one half turns to form a tubular supporting core (the binder strip was on the outside) Friction between the rolled film layers was sufficient to hold a six inch 3M 4627S Pull-N-Shrink prestretched tube (PST) in a stretched position
  • PST Pull-N-Shrink prestretched tube
  • a field from a radio frequency power source 60 watts power at 101 MHz frequency
  • a flexible film member was prepared by tacking a two inch by seven inch low density polyethylene film (0 04 inch thickness) to a similar sized susceptor composite binder strip This was then cut in half to give two one inch by seven inch insert parts
  • a five and one half inch length of polyethylene tubing (pipe) (0 135 inch wall thickness, one and one quarter inch inside diameter) was used as a supporting core for a 3M 4630S Pull-N-Stretch shrinktube (PST)
  • a combined telecommunication coax cable splice (Superior Cable 05/95 - 3 x 22 - BSW/NSE - 1 1/60% with RG-1 1 coax cable connector and dropwires spliced with 3M Discrete Connectors) was centered in the PST/supporting core unit, and the insert parts were wound around the coax/BSW cable and pushed up inside each end of the PST/supporting core unit A field from a radio frequency power source (80 watts power at 102 ).
  • a next layer of foam tape 25 is placed over the resistive wire 142, and disposed around the support core 12 over the resistive wire 142 is a fiberglass cloth 144
  • a shrinkable tube 24 is then disposed over the fiberglass cloth 144
  • the shrinkable tube 24 may cover only portions, such as end portions, or the entire shrinkable tube 24, as desired
  • the fiberglass cloth 144 insulates the resistive wire 142 from the shrinkable tube 24 and serves to concentrate heat from the resistive wire 142 when supplied with direct or alternating current sufficient for melting or softening the ends of the support core 12
  • the wire can be coated, imbedded or laminated in a strip of suitable sealant material such as polyethylene or polyethylene elastomer
  • the resistive sealed closure apparatus 140 forms a sealed closure around a section of cable (not shown) upon resistive heating via the resistive wire 142 to melt or soften the support pipe 12
  • the melting or softening of the support pipe 12 allows the shrinkable tube 24 to cause the support pipe to collapse upon and bind to the outer jacket of the cable, in a manner like those previously described
  • An example of a sealed closure formed by resistive heating follows A supporting pipe assembly was prepared as has been described in other examples herein, using Pelican Nichrome 60 Resistance Wire on a six (6) inch supporting pipe (one inch outside diameter, one-eighth inch wall thickness) and two (2) inch 3M 4630 Pull-N-Shrink tubes (PST) over each end of the supporting pipe
  • PST Pull-N-Shrink tubes
  • the supporting pipe assembly was then bonded to the two cables and the flexible film member insert by using a power source to heat the nichrome wire
  • the heating caused the polyethylene to soften and flow around the cables and the inside of the PST This allowed the pressure of the PST to cause collapse of the supporting pipe around the cables, forming a sealing bond
  • the nichrome wire was heated to soften the open end of the supporting pipe assembly, so that it would flow together from the pressure of the PST to seal the open end
  • the central position of the supporting pipe assembly did not soften and served as a protected closure over the cables
  • the shrinkable tube 24 may be placed over the entire support pipe 12, as well as the resistive wires 142, the foam tape layers, and the fiberglass cloth 144 Such an arrangement, upon resistive heating, serves to collapse the entire length of the support pipe 12 and shrinkable tube 24 onto the cable and to bond them with the cable over that entire length
  • a supporting pipe assembly was prepared using a six (6) inch supporting pipe (one-inch outside diameter, one-eighth inch wall thickness) with two (2) inch 3M 4629 Pull-N-Shrink Tubing over one end Dow EngageTM 7090329-2 (available from the Dow Chemical Company, Midland, Michigan) was used as the sealing material and was prepared as follows A film of EngageTM (approximately 3 inches by 4 inches with a thickness of 1 175 inch) was heat-pressed to a thickness of 1050 inch using a metal mold of the same thickness Next, nichrome 80 wire ribbon (Pelican Wire Company) 125 inch wide and 005 inch thick was soldered onto the EngageTM material in a rectangular block pattern fitting inside a border having dimensions of 2 25 inches by 1 inch Next, an EngageTM piece of identical size was placed over this piece and the two were heat pressed to a thickness of

Abstract

A sealed closure (30) for a cable (20) of the type having a low surface energy outer jacket includes a support core (12) for housing the cable (20). A bondable material between the support core (12) and the outer jacket (20b) of the cable (20) fuses the support core and the bondable material with the outer jacket of the cable. This fusing seals the cable (20) and the support core (12). The sealed closure (30) may also include a shrinkable tube (24) covering the support core (12). The shrinkable tube (24) serves to collapse the support core (12) during bonding, and the shrinkable tube (24) also fuses with the support core (12), the bondable material, and the outer jacket (20b).

Description

SEALED CLOSURE WITH SUPPORT CORE SYSTEMS AND METHODS
Background of the Invention
The present invention generally relates to sealed protective sleeves or closures for spliced or damaged sections of cables carrying electrical current or optic signals for a variety of applications, especially electronic and fiber optic signal carrying cables for telecommunications and computer networks, and, more particularly, to such closures comprising an elastomeric cover portion and a thermoplastic element that acts as a support core and, during installation, provides fluid material to seal around the protected part of the cable and form a bond between the inner surface of the elastomeric cover and the outer surface of the cable insulating cover. Several sealed closures and methods for sealed closure have typically been employed to seal portions of cables, such as electronics and communications cables having conductor elements and a low surface energy outer jacket Although the terms "conductor" and "conductor elements" are used herein, it is to be understood that the terms refer here to not only electrical conductors, but also to any and all other materials and paths for communication, such as optic fibers and others. The low surface energy outer jacket of these cables, typically polyethylene, polypropylene, or an inclusive co-polymer, forms a protective sheath around the conductor elements, This low surface energy outer jacket serves as a barrier to contact of environmental conditions with the conductor elements If the integrity of the outer jacket of these cables is compromised, however, for example, by wear damage, removal to access the conductor elements, or other conditions, the outer jacket does not sufficiently seal the conductor elements from the environment As may be expected, the integrity of the cables, including their useful life expectancy, their operation, and their other characteristics, may be affected if the seal of the outer jacket is not repaired or replaced
Closures of this type are important because environmental conditions that contact the cables, particularly, the conductor elements, may damage the integrity, function, and useabi ty of the cables In many applications, it is, thus, imperative and desirable to seal the conductor elements of the cables to protect against environmental effects Closures for cables have been particularly important in locations of cable splices and outer jacket deterioration With conventional sealed closures for these purposes, an outer covering or housing has been placed over portions of the cable in locations of exposed conductor elements, such as at splices and deteriorated sections The covering or housing has then been sealed with the remaining outer jacket of the cables to seal the conductor elements within the covering or housing Typically, the covering or housing has been sealed with the outer jacket by pressure, for example, by shrinking the covering or housing against the cable outer jacket, and/or by sealants, for example, by adhering the covering or housing to the cable outer jacket and/or expanding the sealant to fill voids between the covering or housing and outer jacket
An example of a shrinkable covering or housing is disclosed in U S Patent Nos 5,080,942 and 4,389,440 Various sealants of the type described, for example, mastic or gel, are generally conventional
In connection with the conventional seals, heating has sometimes served to shrink the covering or housing or to adhese or expand the sealant Various methods of heating the covering or housing and/or sealant, and, in some instances, the outer jacket, have been employed to cause the covering or housing to seal against the outer jacket by pressure of the covering or housing due to shrinkage or of the sealant due to expansion or adhesion The heating for these purposes has typically been either by resistive, inductive, external torch, or chemical process In resistive heating, wires of high resistance are located in the vicinity of the desired heating Electrical current is fed to the wires, and the resistance of the wires generates heat The current may be varied to obtain the desired heat for the heating In induction heating, electromagnetic elements are placed in the vicinity of the desired heating and a magnetic field is oscillated around the electromagnetic elements The electromagnetic elements in the magnetic field generate heat for the heating
The covering or housing of the sealed closure, for example, if shrinkable, has, in certain cases, been supported by a structural core over which the covering or housing is placed in order that the cable may be placed within the structural core and, thus, also within the covering or housing. This has been necessary because the covering or housing, alone, is not easily stretched to place over the cable The structural core has been removed from around the cable and from within the covering or housing prior to shrinking the covering or housing to seal the covering or housing against the outer jacket of the cable. The structural core, as removed from around the cable and from within the covering or housing, is treated as refuse Once the structural core has been so removed, the covering or housing then contracts and, thus, achieves pressure sealing, as previously described
A problem with use of the structural core is that its removal requires extra steps in the sealed closure implementation process Also, the structural core, once removed, is refuse and must be properly disposed Even more, once the structural core is removed, the sealed closure is not rigid, which, for example, may be desirable when the closure is used to seal cable splices Furthermore, the structural core is not easily useable for cable that does not have a break in the cable near the desired location along the cable of the sealed closure With the structural core, the cable must be fed through the structural core and the structural core, together with the sealed closure supported thereby, must be passed along the cable to the desired location along the cable Such feeding of the cable through the structural core is not always practical, particularly in many field operations involving sealed closures
An additional problem with prior sealed closures has been that the seal has been dependent upon the effectiveness of the covering or housing materials and the materials of any sealants in forming the pressure seal of the covering or housing with the outer jacket of the cable Typically, the pressure seal effectiveness has been dictated by the shrinkability of the housing or covering and/or the expandability or adhesability of the sealants It has been quite difficult with conventional heating and such coverings or housings and/or sealants to effectively seal the low surface energy outer jacket of cables This difficulty has been due to the temperatures and materials which have been possible for such purposes
Therefore, what is needed is a system and method of sealed closure of cables, which system and method avoid the problems of the conventional seal techniques and the typical structural core and which provide advantages of improved sealing, such as by materials bonding of the closure covering or housing and/or the sealant to the cable outer jacket, as well as ease of use, low cost, field- use simplicity, and others
Summary of the Tnvention Embodiments of the present invention, accordingly, provide systems and methods for sealed closure of cables using a support core. The embodiments avoid problems of conventional cable seal techniques and provide advantages of improved sealing, ease of use, low cost, field-use simplicity, and other advantages
To this end, one embodiment of the invention is a kit for sealed closure of a cable of the type having a low surface energy outer jacket The kit includes a support core capable of housing the cable and a bondable material, locatable between the support core and the outer jacket, for fusion bonding of the support core, the bondable material and the outer jacket The fusion bonding seals the cable with the support core
Another embodiment of the invention is a sealed closure for a cable of the type having a low surface energy outer jacket The sealed closure includes a support core for housing the cable and a bondable material between the support core and the outer jacket of the cable The support core, the bondable material, and the outer jacket are fused, sealing the cable with the support core
Yet another embodiment of invention is a method for sealing closure of a cable having a low surface energy outer jacket. The method includes the steps of housing the cable within a support core and bonding the support core to the cable Another embodiment of the invention is a kit for sealed closure of a cable of the type having a low surface energy outer jacket The kit includes a tubular support core having a longitudinal split to allow the tubular support core to be placed around the cable, a first bondable material locatable at the longitudinal split to allow the longitudinal split of the tubular support core to be re-joined, and a second bondable material, locatable between the support core and the outer jacket, for fusion bonding of the tubular support core, the bondable material, and the outer jacket The fusion bonding seals the cable with the support core
A further embodiment of the invention is a sealed closure for a cable of the type having a low surface energy outer jacket The sealed closure includes a tubular support core placed around the cable The tubular support core has a longitudinal split. The sealed closure also includes a first bondable material at the longitudinal split for re-joining the longitudinal split of the tubular support core and a second bondable material between the support core and the outer jacket of the cable The longitudinal split is re-joined by the first bondable material The tubular support core, the second bondable material, and the outer jacket of the cable are fused This seals the cable with the support core
Another embodiment of the invention is a method for sealing closure of a cable having a low surface energy outer jacket The method includes the steps of placing a tubular support core having a longitudinal split around the cable, rejoining the longitudinal split, and bonding the tubular support core to the cable Yet another embodiment of the invention is a kit for sealed closure of a hole in a low surface energy outer jacket of a cable The kit includes a polymer film for wrapping around the cable, over the hole and in the vicinity of the hole along the cable and a bondable material for placing over the polymer film Fusion bonding seals the polymer film and the bondable material with the outer jacket and the hole of the cable
Another embodiment of the invention is a sealed closure for repairing a hole in a low surface energy outer jacket of a cable The sealed closure includes a polymer film around the cable, over the hole and in the vicinity of the hole along the outer jacket of the cable and a bondable material over the polymer film The polymer film and the bondable material are fused with the outer jacket and the hole of the cable
Yet another embodiment of the invention is a kit for sealed closure of a cable of the type having a low surface energy outer jacket The kit includes a support core capable of housing the cable, a shrinkable tube capable of covering the support core, and a resistive wire locatable on the shrinkable tube Resistive heating fuses the support core and the shrinkable tube with the outer jacket of the cable, thereby sealing the cable with the support core
Another embodiment of the invention is a sealed closure for a cable having a low surface energy outer jacket The sealed closure includes a support core for housing the cable, a shrinkable tube covering the support core, and a resistive wire wrapped around the shrinkable tube The support core and the shrinkable tube are fused with the outer jacket of the cable by resistive heating via the resistive wire
Yet another embodiment of the invention is a method for sealed closure of a cable having a low surface energy outer jacket The method includes the steps of housing the cable within a support core, wrapping a resistive wire around the support core, covering the support core with a shrinkable tube, and supplying current to the resistive wire to create heat The support core and the shrinkable tube are fused with the outer jacket of the cable
Brief Description of the Drawings Fig 1 is a perspective, partial cut-away, view of a closure apparatus with a cable (in phantom) extending therethrough, prior to bonding of the closure apparatus to an outer jacket of the cable, all according to embodiments of the present invention
Fig 2 is a perspective, partial cut-away, view of a sealed closure formed by the closure apparatus of Fig 1, upon bonding of the closure apparatus at its ends to the outer jacket of the cable, all according to embodiments of the present invention Fig 3 is a flow diagram of a method for implementing the sealed closure of Fig 2, according to embodiments of the present invention
Fig 4 is a perspective view of a split closure apparatus according to embodiments of the present invention Fig 5 is a perspective view of a sealed split closure formed by the split closure apparatus of Fig 4, upon bonding of the split of the split closure apparatus, all according to embodiments of the present invention
Fig 6 is a flow diagram of a method for implementing the sealed split closure of Fig 5, according to embodiments of the present invention Fig 7 is a perspective, partial cut-away view, of a repair closure apparatus with a cable (in phantom) having a hole through the outer jacket to the conductor elements extending therethrough, prior to bonding of the repair closure apparatus to the outer jacket of the cable and to the hole and the conductor elements within the hole, all according to embodiments of the present invention
Fig 8 is a perspective, partial cut-away, view of a sealed repair closure formed by the repair closure apparatus of Fig 7, upon bonding of the repair closure apparatus along its entire length to the outer jacket, the hole, and the conductor elements within the hole of the cable, all according to embodiments of the present invention
Fig 9 is a perspective view of a polymer film and the binder of a shrink repair closure apparatus, each disposed over the hole in the outer jacket of the cable, wherein the hole exposes the conductor elements through the hole, according to embodiments of the present invention
Fig 10 is a perspective view of a heat shrink repair closure formed by bonding, from the shrink repair closure apparatus of Fig 9 which also includes a tape wrapped around the cable and over the hole, the polymer film, and the binder, according to embodiments of the present invention
Fig 1 1 is a flow diagram of a method for implementing the heat shrink repair closure of Fig 10, according to embodiments of the present invention
Fig 12 is a perspective view of a resistive sealed closure apparatus according to embodiments of the present invention
Like numerals used for reference in the drawings refer to identical elements
Detailed Description of the Preferred Embodiment
Referring to Fig 1, the reference numeral 10 refers, generally, to a closure apparatus according to embodiments of the invention The closure apparatus 10 comprises a support core 12 The support core 12 forms a hollow conduit 14 that extends longitudinally through the support core 12 The support core 12 is a unitary piece with an inner side 16 and an outer side 18 The hollow conduit 14 of the support core 12 is of sufficient size to accommodate a conventional cable 20
(shown in phantom), for example, a communications or electrical cable, having a conductor 20a and an outer jacket 20b shielding the conductor 20a from the environment The cable 20 is shown spliced to a substantially identical cable within the hollow conduit 14 of the support core 12
The closure apparatus 10 also includes an environmentally resilient, shrinkable tube 24 The support core 12 is located concentrically within the shrinkable tube 24, and each of the support core 12 and the shrinkable tube 24 have approximately the same longitudinal length Between the support core 12 and the shrinkable tube 24, at each end thereof, is disposed a binder 22 The binder 22 is located in the vicinity of the outer jacket 20b when the closure apparatus 10, as shown in Fig 1, is located in place for sealing the conductor element 20a where not covered by the outer jacket 20b, also as shown in Fig 1 The binder 22 is not located in the vicinity between the ends of the support core 12 and the shrinkable tube 24 where the conductor elements 20a are not covered by the outer jacket 20b
Referring to Figs 1 and 2, in conjunction, the closure apparatus 10, when heated at its ends where the binder 22 is situated, collapses onto and joins with the outer jacket 20b at those ends to form the sealed closure 30 At the ends of the sealed closure 30, where the binder 22 was located prior to heating, the support core 12, the binder 22, and the shrinkable tube 24 are fused with the outer jacket 20b of the cable 20 forming the fused ends 32 Along the longitudinal length of the sealed closure 30 between the fused ends 32, the shrinkable tube 24 with the support core 12 concentrically disposed therein are not collapsed onto the cable 20 and maintain substantially their original configuration as in the closure apparatus 10
The fused ends 32 seahngly enclose those portions of the conductor element 20a of the cable 20 not covered by the outer jacket 20b, along with portions of the outer jacket 20b of the cable 20 between the fused ends 32 By so fusingly joining the sealed closure 30 at the fused ends 32 to the outer jacket 20b of the cable 20, the conductor elements 20a are sealed from the environment outside outer jacket 20b and the sealed closure 30 The sealed closure 30 provides permanent bonding to the low energy surface of the outer jacket 20b of the cable 20 at the fused ends 32, with a permanent air and water tight bond between the sealed closure 30 and the cable jacket 20b to prevent entry of environmental conditions into the sealed closure 30
The outer jacket 20b of the cable 20 is conventionally comprised of a polyethylene, polypropylene, or an inclusive copolymer and, in any event, is a low energy surface that serves as an electrical and environmental condition insulator A variety of suitable materials may be employed for the closure apparatus 10, and, thus, comprise the sealed closure 30 For example, the shrinkable tube 24 may be a tubular-shaped elastomeric material which is supported in a stretched condition on the support core 12 Certain pre-stretched tubes useable as the shrinkable tube 24 are disclosed, for example, in U.S Patent No 5,080,942 and U S Patent No 4,389,440, each assigned to the same assignee of the present invention and each incorporated herein by this reference A suitable material for the shrinkable tube 24 is an elastomer, such as oil extended ethylene propylene diene monomers or ethylene propylene monomers (EPDM or EPM) Other materials for the shrinkable tube 24 include compounded synthetic rubbers or other elastomers, for example, neoprene, butyl rubber elastomers, polypropylene/butyl rubber elastomers, polypropylene/EPDM elastomers, ethylene propylene copolymers, or other similar materials.
The support core 12 supports the shrinkable tube 24 in a stretched condition The support core 12 may be tubular-shaped and of outside diameter slightly less than the inner diameter of the shrinkable tube 24 in its stretched state The support core 12 is formed of a material capable of maintaining the shrinkable tube 24 in a stretched state when the support core 12 is placed into the shrinkable tube 24 The material has a melting or softening temperature below the temperature which would affect the integrity of the shrinkable tube 24 A low melting point, low density polyethylene tube or pipe is suitable
As for the binder 22, a material which binds with the materials of the shrinkable tube 24, the support core 12, and the outer jacket 20b of the cable 20 at the softening or melting temperatures of the support core 12 is employed An example of a binder 22 suitable for the sealed closure 30 is a composite material for induction bonding (also referred to as "electromagnetic bonding") as disclosed in U.S Patent Application Ser No 08/412,966, filed March 29, 1995, titled "Electromagnetic-Power-Absorbing Composite", assigned to the same assignee of the present invention and incorporated herein by this reference That patent application discloses, among other things, an electromagnetic-power-absorbing composite comprising a plurality of multilayered flakes dispersed in a binder agent The binder agent is any of a variety of suitable polymers or polymer blends, such as thermoplastic polymers, thermoplastic elastomers, and thermally activated or accelerated cure polymers, or a polymeric or nonpolymeπc adhesive The multilayered flakes may include at least one layer pair comprising one thin film crystalline ferromagnetic metal layer adjacent to one thin film dielectric layer The multilayered flakes may be dispersed in a binder composition In any event, the binder composition is generally acted upon physically and/or chemically by heat generated within the composite due to the interaction of electromagnetic power with the multilayered flakes The composite material described is suitable as the binder 22 for the sealed closure 30 Equipment for providing the electromagnetic power to perform induction bonding to form the sealed closure 30 with the foregoing composite material as the binder 22 is disclosed, for example, in U S Patent Application Ser No 08/413, 1 19, filed March 29, 1995, titled "Induction Heating System for Fusion Bonding", assigned to the same assignee of the present invention and incorporated herein by this reference
Referring to Fig 3, in conjunction with Figs 1 and 2, the reference numeral 40 refers, generally, to a method for implementing the sealed closure 30, according to embodiments of the invention In step 42, the support core 12 is cut to an appropπate length, such that the ends of the support core 12 overlap the outer jacket 20b adjacent the conductor elements 20a when the cable 20 is placed within the closure apparatus 10 and positioned therein as shown in Fig 1
In a step 44, the binder 22 is placed at the ends of the support core 12 over portions of the outer side 18 of the support core 12 The longitudinal length of the support core 12 over which the binder 22 is placed is less than the longitudinal length by which the outer jacket 20b of the cable 20 is positioned within the closure apparatus 10, as shown in Fig 1 The binder 22, in that placement on the outer side 18, is adhered, for example, by an adhesive, bonded, for example, by melting, or otherwise attached to the support core 12
In a step 46, the shrinkable tube 24 is stretched and placed over the support core 12 Once the support core 12 has been located within the shrinkable tube 24, the shrinkable tube 24 shrinks against the outer side 18 of the support core 12 and is supported by the support core 12 The binder 22 that is disposed at the ends of the support core 12 remains between the outer side 18 of the support core 12 and the shrinkable tube 24 at those ends
In a step 48, the cable 20 is positioned withm the support core 20 so that the conductor elements 20a of the cable 20 which are not covered by the outer jacket 20b of the cable 20 are maintained within the hollow conduit 14 formed by the support core 12 The conductor elements 20a are so positioned such that the binder 22 disposed at the ends of the support core 12 is in the vicinity of the outer jacket 20b
In a step 50, the ends of the closure apparatus 10 in the vicinity of the outer jacket 20b are bonded to the outer jacket 20b at those locations The step 50 of bonding the ends of the closure apparatus 10 to the outer jacket 20b seals the closure apparatus 10 with the outer jacket 20b, thereby forming the sealed closure 30 The bonding is achieved by heating the ends of the closure apparatus 10 to a temperature sufficient to melt the support core 12 and to cause the binder 22 to fuse the support core 12, the binder 22, and the shrinkable tube 24 with the outer jacket 20b of the cable 20 The shrinkable tube 24 provides uniform pressure to conform the support core 12 and the binder 22 around the outer jacket 20b to insure bonding
An example of the method 40 follows
Two eighteen (18) inch sections of fifty (50) pair twenty four (24) gauge telecommunication cables (SEALPIC SxOl 94) were spliced together through 3M Modules (available from the Minnesota Mining and Manufacturing Company of St Paul, Minnesota ("3M") in an inline splice (I e , cables are aligned with each end in the opposite direction and spliced) Then, two one-half inch "susceptor composite binder strips" (0 015 inch thick low density polyethylene strips containing 5% "susceptor composite flakes"-J226-2 experimental production run) were tacked, using a soldering iron, around the cable jackets on each side of the splice about eleven (1 1) inches apart The susceptor composite flakes used were radio frequency absorbing materials comprising a plurality of multilayered flakes made of thin film crystalline ferromagnetic metal layers, such as a NiFe alloy, stacked alternately with thin film dielectric layers, such as SiO The susceptor composite binder strip used was a suitable binder agent, such as polyethylene, in a strip or tape form in which is dispersed about 1 to 10 percent susceptor composite flakes The susceptor composite binder strip provides binding of two objects together using a radio frequency power at a frequency of about 5 MHz to about 6000 MHz in the form of an oscillating magnetic field The oscillating magnetic field intersects the susceptor composite flakes of the susceptor composite binder strip so that heat is generated which melts the binder agent and fuses, bonding the objects together
Two 3M 463 IS Pull-N-Shrink tubes (prestretched tubes - PST) were placed on a twelve (12) inch white polyethylene tube (pipe) (0 13 inch wall thickness, 1 40 inch internal diameter) so that the PST's hung just slightly over the ends of the tube The tube/PST unit was slid over the cable splice and positioned so that the remaining cable jacket on each side of the splice was partially contained within the tube PST unit Two flexible members comprised of low density polyethylene film (0 04 inch thickness, one inch by fifteen inches) were sandwiched between two susceptor composite binder strips (one-half inch by fifteen inches) and tacked together Each flexible film member was wrapped tightly around the cables over the susceptor composite binder strip tacked on the cable and pushed up into each end of the supporting core
A field from a radio frequency power source (power of about 50 watts to about 100 watts, 102 MHz frequency) was used by placing the "tip antenna" over first one end and then the other end of the tube/PST unit above the susceptor composite binder strips This caused the flexible film insert part to melt and the end of the tube to collapse, allowing the PST to contract around the cable on each side of the splice and forming a sealing bond between the cable sheath and the PST material. The central portion of the tube maintained its shape intact to provide a rigid protective closure over the spliced modules After cooling, heat shrink sleeves were placed over each end of the cable, with one sleeve equipped with an air fitting The cable was then pressurized with four (4) psi and placed inside a water tank The cable remained pressurized for seven (7) days without any leaks detected The pressure was then increased to fifteen (15) psi for twenty four (24) hours and water tank tested for leaks, without any leaks detected Hand pressure could not separate the PST material from the outer jacket of the cable
Several alternatives are possible in the foregoing embodiments Although certain specific materials are described herein, other materials with similar characteristics in relation to other materials employed are also suitable Also, the shrinkable tube 24, rather than being placed over the entire longitudinal length of the support core 12, can be placed only at the ends of the support core 12 in the vicinity of the binder 22 A shrinkable tube 24 that extends over the entire length of the support core 12, however, can offer advantages of additional impact resistance in the area of the sealed closure 30 Even more, the binder 22 may additionally or alternatively be placed between the support core 12 and the outer jacket 20b of the cable 20
Furthermore, a plurality of support cores 12 could be employed The plurality of support cores 12 can provide a plurality of passages, extending from one end thereof to the other end thereof, for receiving a plurality of cables 20 or wires or splices of the cables 20 Such an arrangement can allow more complete bonding to the cable 20 or to insulation of individual wires or splices of wires, upon softening or melting of the plurality of support cores 12 In such an arrangement, individual or multiple wires or splices can be themselves sealed The plurality of support cores 12, in such instance, can be of varied sizes to allow varied diameter- sized cables or wires to be disposed therein Additionally, one or more of the plurality of support cores 12 could be a solid that is an electromagnetic-power- absorbing composite, such as that previously mentioned and disclosed in the incorporated patents and patent applications Also, one or more additional supportive cores could be formed of such a composite having more or less of the electromagnetic-power-absorbing flakes than in the composite there disclosed or the various supportive cores may themselves have varied flake compositions, for example, to ensure softening or melting within the center of the closure apparatus 10.
Referring to Fig. 4, the reference numeral 51 refers, generally, to a split closure apparatus according to embodiments of the invention The split closure apparatus 50, like the closure apparatus 10 (shown in Fig 1), includes the support core 12 and the shrinkable tube 24 The shrinkable tube 24 is adhered to the outer side 18 of the support core 12 The support core 12 and the shrinkable tube 24, however, are split 52 along the longitudinal length thereof Diametrically opposite the split 52 along the longitudinal length of the inner side 16 of the support core 12, a channel 54, for example, a V-shaped channel, is formed partway through the support core 12 The channel 54 hingedly allows the split 52 to be opened by spreading respective portions of the support core 12 and the shrinkable tube 24 adjacent the split 52 Alternatively, the channel 54 is not necessary if the split 52 of the support core 12 can be suitably spread without it In any event, longitudinal faces at the split 52 of the support core 12 and the shrinkable tube 24 are the inner faces 56 and the outer faces 58, respectively The support core 12 includes a radio frequency antenna wire 60 that is embedded in and runs longitudinally through the support core 12 on each side of the split 52 Alternately, if resistive heating is to be employed as later discussed, the support core 12 includes a resistance wire, in place of the antenna wire 62, that is imbedded in and runs longitudinally through the support core 12 on each side of the split 52
There are several possibilities for adhering the shrinkable tube 24 to the support core 12. One possibility is to adhere the shrinkable tube 24 to the support core 12 by a binder agent, such as that of the binder 22 previously described with respect to Figs 1-3, either before or after the shrinkable tube 24 and the support core 12 are split A binder agent that is different than the material of the binder 22, however, is preferable For example, a binder agent that binds when subjected to an electromagnetic field in the GHz range (such as that produced by a conventional microwave heater in a factory setting) but that does not bind and is not detrimentally affected by such a field in the MHz range (such as that produced by the equipment for providing electromagnetic power, previously discussed) Alternatively, an adhesive that maintains a bond in the presence of high temperature is useable
Referring to Figs 4 and 5, the split closure apparatus 51 forms a sealed split closure 61 The sealed split closure 61 is fused at the inner faces 56 adjacent the split 52 Bonding may be achieved by a binding material 62 disposed on the faces 56. The binding material 62 may be an adhesive, a binding agent, a weld, or some other fusing mechanism The electromagnetic-power-absorbing composite, previously described, is a suitable binding material 62 As the split 52 is fused, the sealed split closure 61 is tubular
The split closure apparatus 51 is particularly useful for forming the sealed split closure 61 in the field and in other circumstances In particular, the cable 20, requiring sealing enclosure along its length because of an exposure of the conductor elements 20a outside the outer jacket 20b, can not in certain instances be easily inserted through a tubular member, such as the closure apparatus 10, because an end of the cable 20 is not available In those instances, sealingly enclosing the conductor elements 20a may be achieved by enveloping the split closure apparatus 51 around the cable 20 in the vicinity of the conductor elements 20a so exposed
Referring to Fig 6, the reference numeral 70 refers, generally, to a method for implementing a sealed split closure 61 , according to embodiments of the invention In a step 72, the split 52 of the split closure apparatus 51 is widened by application of force to spread the inner faces 56 and the outer faces 58 adjacent the split 52 Spreading of the faces 56 and 58 causes the channel 54 to hingedly widen In a step 74, the cable 20 is, along its length, passed through the split 52 to within the support core 12 In a step 76, the split closure apparatus 51 is then positioned in the vicinity of the conductor elements 20 to be sealed In a step 78, once the cable 20 is passed through the split 52, the inner faces
56 and the outer faces 58 adjacent the split 52 are forced together until the adjacent faces 56 and 58 abut As the faces 56 and 58 are so forced together, the channel 54 hingedly narrows In a step 80, the split closure apparatus 51 is then maintained with the faces 56 and 58 so abutting, for example, by a clamp, tape, adhesive, or some other binding mechanism which may be internal or external to the split closure apparatus 51 or otherwise In a step 82, as so maintained, the split 52 of the split closure apparatus 51 is bonded If necessary for the bonding of the split 52, the binding material 62, for example, the electromagnetic-power-absorbing composite previously described or the others described, is disposed on the inner faces 56 adjacent the split 52 prior to the step 78. In the fusion step 82, the radio frequency antenna wire 60 is exposed to an oscillating electromagnetic field, for example, in the manner previously described. The oscillating electromagnetic field, acting on the antenna wire, thereby causes the binding material 62 to bond the faces 56 together.
Alternatively, in the fusion step 82, other bonding methods and materials may be employed. For example, the split 52 is bondable by resistive heating, either with or without binding material 62, by a bead of suitable adhesive, or otherwise. For resistive heating, the radio frequency antenna wire 60 (Figs 4-5) is replaced with a resistive wire, for example, a stainless steel, nickel chromium, or other suitably resistive material, that is embedded in and runs longitudinally through the wall of the support core 12 adjacent the split 52 or the resistive wire is otherwise placed in the vicinity of the faces 56 at the split 52 If desired, binding material 62, for example, polyethylene or Engage ™ material, may be disposed at the faces 56 In any event, when the split 52 is rejoined by pressing the faces 56 together, the resistive wire is located at or between the faces 56 One or more lengths of resistive wire may be so located Bonding of the split 52 of the split closure apparatus 51 is achieved by supplying an alternating current (AC) or direct current (DC) to the resistive wire The wire generates heat and fuses the faces 56 and binding material or the faces 56, alone, as the case may be. As those skilled in the art will appreciate, this same resistive heating can also be employed to seal and fuse cables with the support core as later described
Once the faces 56 are so bonded by the method 70, the bonding step 50, previously described with respect to the method 40 and Fig 3, provides a sealed closure similar to the sealed closure 30 (shown in Fig. 2) An example of the method 70 follows: A susceptor composite binding strip (as described in an earlier example) bondable at a high frequency (about 1 to 3 GHz) (0 5" x 6.0" x 0 028") was heat- staked lengthwise to a polyethylene tube (1 65" OD, 6 0" long, 0 19" wall thickness) and then a 3M 463 I S Pull-N-Shrink (PST) tube (0 68" unstretched ID) was collapsed onto the tube The tube/PST unit was heated in a conventional microwave oven (approximately 1 GHz to approximately 3 GHz) for five (5) minutes, so that the tube was bonded to the PST
After cooling, the tube/PST unit was split lengthwise in the region of the susceptor composite binding strip The diametrically opposite side of the inner wall of the tube was notched with a lengthwise V-channel to create a hinge for the closure The split seam of the tube was notched on both sides of the cut surface to allow for installation of a radio frequency antenna wire (tinned copper tubular braid, approximately 22 awg) The antenna wire was run embedded in the tube wall longitudinally along each side adjacent the cut surface
A strip of susceptor composite material bondable at a lower frequency than the strip for bonding the PST to the polyethylene tube binder strip (6 0" x 0 15" x 0.016") was heat-staked to the cut mating surfaces between the two sides of the split seam. The split seam in the tube/PST unit was forced together using a vise The split seam was then permanently bonded together using a field from a radio frequency power source (50 MHz, 75 W, two minutes)
A 0.50" OD cable (HDPE sheath, aluminum shield, copper conductors) was run through the tube (the cable sheath and shield were cut in the center of the cable to allow for pressure check) Each end of the tube/PST unit was prepared by spiraling susceptor strips and low density polyethylene (LPDE) strips around the cable until the air gap between the cable and closure wall was filled The susceptor strips were 0.25" wide and the LDPE strips were 0 75" wide The ends of the closure were sealed individually by applying an oscillating magnetic field from a radio frequency power source (95 MHz, 75 W) through a 3/4" stainless steel braided antenna loop for about 8-9 minutes This melted the end filler material and softened the ends of the tube/PST unit so that the ends collapsed onto the cable in the heating zone area After cooling, the ends of the cable were capped and the closure was flash tested in one foot of water at 10 psi for 10 minutes with no visible air bubbles In an alternative embodiment, the shrinkable tube 24 is not employed with the split closure apparatus 51 Instead, once the cable 20 is inserted through the split 52 in the support core 12 and the split 52 is fused as previously described, the ends of the support core 12 are double wrapped with a stretchable tape that is stretched and wrapped so that it applies pressure to the support core 12 The tape has an aggressive adhesive which withstands high temperatures, and has an affinity to maintain its pre-stretched shape The tape maintains closure of the split 52 of the support core 12 The ends of the support core 12 are then heated and bonded to the cable 20, for example, by an electromagnetic field acting on the binder 22, as previously described The heating softens the ends of the support tube 12 and causes the ends to collapse onto the cable jacket 20b
An example of the alternative embodiment follows
A polyethylene tube with susceptor composite binder strip at its ends was prepared according to the immediately preceding example No Pull-N-Shrink tube (PST) was attached to the tube The split of the tube was resealed and the ends were prepared as also described in that example The ends of the tube were double- wrapped with a tape. Two different 2" wide tapes were employed in separate tests A first tape was a double rubber tape (Plymouth DR Rubber Tape, spec 6863, TL- 192, cat. no 2013) and a second tape was a rubber mastic tape (3M Scotch 2228) Each closure end was heated for 8-9 minutes, as described in that immediately preceding example, until the tape collapsed the softened ends of the tube, sealing it around the cable Both taped closures passed a 10 psi, ten minute flash test
Referring to Fig 7, the reference numeral 90 refers, generally, to a repair closure apparatus, according to embodiments of the present invention The repair closure apparatus 90 is substantially similar to the closure apparatus 10 of Fig 1, except that the binder 22 extends entirely along the outer side 18 of the support core 12 between the support core 12 and the shrinkable tube 24 The cable 20 (in phantom) exhibits a hole 20c (rather than a splice, as was shown in Fig. 1) in which the conductor elements 20a are exposed through the outer jacket 20b of the cable 20.
Referring to Figs 7 and 8, in conjunction, the repair closure apparatus 90, when heated along its length where the binder 22 is situated, collapses onto and joins, all along its length, with the outer jacket 20b and with the hole 20c and the conductor elements 20a exposed through the hole 20c. The reference numeral 100 in Fig 8 refers, generally, to a repair sealed closure 100 Referring back to Fig 3, a method of implementing the repair sealed closure
100 is identical to the method 40 of Fig 3 and as described herein, except that the entire length of the repair closure apparatus is bonded to the outer jacket 20b of the cable to cover and fill the hole 20c
An example of the method follows A 100 pair telecommunication cable (10042 SEALPIC), approximately 16 inches long, had a 1/4" diameter hole drilled through the sheath exposing the individual wire pairs An assembly was prepared by tacking (with a soldering gun) a susceptor composite binder strip (a 0 015 inch thick low density polyethylene strip - 5 1/4 inches long and 3 inches wide - containing 5% susceptor composite flakes) (J226-2 experimental production run)) on the outside of a 1 1/4" diameter polyethylene pipe (0 135 inch wall thickness) The pipe with tacked susceptor composite binder strip was then used as a supporting core for a 3M 4630 S Pull-N- Shrink prestretched (PST) tube.
The PST tube and supporting core was then slid over the cable and positioned over the drilled hole in the cable A field from a radio frequency power source (95 watt power at 102 8 MHz frequency) was generated by moving the "tip" from the lengthwise center of the PST tube and supporting core to each end thereof. This generated heat to soften the supporting core and allow the PST tube to contract around and seal the supporting core and PST tube in and over the hole and to bond the elastomeric material of the PST tube to the sheath of the cable
Referring to Fig 9, the reference numeral 1 10 refers, generally, to a shrink repair closure apparatus The shrink repair closure apparatus 1 10 is comprised of a polymer film 1 1 1 (shown in phantom) that is wrapped around the cable 20, over the hole 20c in the outer jacket 20b of the cable 20 in which the conductor elements 20a are exposed The polymer film 1 1 1 is, for example, the same material previously described herein for the support core 20 (shown in Fig 1), such as a low density polyethylene film Around the polymer film 1 1 is disposed the binder 22
Referring to Fig 10, around the binder 22 is wrappingly disposed a tape 122.
The shrink repair closure apparatus 1 10 forms a heat shrink repair closure 120 upon bonding of the tape 122, the binder 22, and the polymer film 1 1 1 to the outer jacket 20b, the hole 20c, and the conductor elements 20a of the cable 20
Referring to Fig. 1 1, the numeral 130 refers, generally, to a method of implementing the heat shrink repair closure 120 In a step 132, the polymer film 1 1 1 is wrapped around the cable 20 to cover the hole 20a In a step 134, the binder 22 is placed on the polymer film 1 1 1 around the cable 20 In a step 136, the tape 122 is wrapped around the binder 22 and, thus, the cable 20 In a step 138, the tape 122, the binder 22, and the polymer film 1 11 are sealingly bonded to the outer jacket 20b, the hole 20c, and the conductor elements 20a of the cable 20 An example of the method follows A cable having a hole through the sheath, exposing the conductive wires was wrapped with a piece of low density polyethylene film (1 inch wide, 2 inches long, 0 04 inch thickness) to cover the hole in the cable A susceptor composite binder strip (1 inch wide, 2 inches long) was then wrapped around the cable atop the polyethylene film The film and the binder strip were held in place by winding 3/4 inch 3M EPR tape around the cable over the binder strip and film
A field from a radio frequency power source (1 1 1 MHz frequency) was then used, as has been previously described in the examples herein, to melt the polyethylene film and the binder strip to fill and seal the hole in the cable and to bond the EPR tape to the sheath insulation After cooling, the cable was equipped as previously described in examples herein and then pressurized with 15 psi and placed in a water tank The cable remained pressurized for seven (7) days with no leakage detected. Hand pressure could not remove the tape
Referring back to Figs 3 and 7-8, the repair closure apparatus 90 is employable to form the repair sealed closure 100 for a coaxial cable as the cable 20 The repair sealed closure 100, in the case of use with a coaxial cable as the cable 20, forms a suitable closure for splices, holes, or other conditions that expose the coaxial conductor elements along the coaxial cable. The method 40 of implementing the repair sealed closure 100 is also applicable in the case of coaxial cable.
Referring back to Figs 1-3, the closure apparatus 10 is also employable to form the sealed closure 30 for a coaxial cable as the cable 20. The sealed closure 30, in the case of use with a coaxial cable, also forms a suitable closure for splices, holes, or other conditions along the coaxial cable. As just disclosed, the method 40 is applicable for implementing the sealed closure 30 for coaxial cable. The sealed closure 30 is, furthermore, particularly useful for a combined coaxial/telecommunication buried service wire cable, where the buried service wire cables are spliced with 3M Discrete Connectors and the coaxial cables are spliced with coaxial cable connectors.
Examples of these uses with coaxial cable follows:
In one example, an assembly was prepared by tacking (with a soldering iron) a susceptor composite binder strip (a 0.015 inch thick low density polyethylene film - six inches long and three inches wide - containing 5% susceptor composite flakes (J226-2 experimental production run)) on the outside of a six inch length of polyethylene pipe (0.135 inch wall thickness, one and one quarter inch diameter) which was then placed within a 3M 3628S Pull-N-Shrink tube (PST) as a supporting core. The assembly was slid over a metallic RG-1 1 coax cable connection made from the 0.3815 inch diameter coax cable stripped away from a combined coaxial/buried service wire cable (Superior Cable 05/95 3 x 22 BSW - NSF 1 1/60% cable). A field from a radio frequency power source (75-100 watts power at 95-100 MHz frequency) was generated by moving the "tip antenna" from the center of the PST to each end. This softened or melted the supporting core and allowed the PST to contract around and seal the coax cable connector and to bond the PST material to the sheath insulation. Hand pressure could not separate the PST material from the coaxial cable sheath after cooling.
In another example, an assembly was prepared by tacking a five and three quarter by twelve inch low density polyethylene film (0.0425 inch thickness) to an approximately same size piece of susceptor composite binder strip. The binder strip was rolled up two and one half turns to form a tubular supporting core (the binder strip was on the outside) Friction between the rolled film layers was sufficient to hold a six inch 3M 4627S Pull-N-Shrink prestretched tube (PST) in a stretched position A metallic RG-1 1 coax cable connection made from the coax cable (described in the immediately preceding paragraph), with dropwire removed, was centered inside the rolled film supporting core/PST unit Then, a field from a radio frequency power source (60 watts power at 101 MHz frequency) was utilized by moving the "tip antenna" from the center of the rolled film supporting core to each end This generated heat to melt or soften the rolled film supporting core and allowed the PST to contract around the coax cable splice After cooling, the PST material could not be separated from the coaxial cable sheath by hand
In another example, a flexible film member was prepared by tacking a two inch by seven inch low density polyethylene film (0 04 inch thickness) to a similar sized susceptor composite binder strip This was then cut in half to give two one inch by seven inch insert parts Separately, a five and one half inch length of polyethylene tubing (pipe) (0 135 inch wall thickness, one and one quarter inch inside diameter) was used as a supporting core for a 3M 4630S Pull-N-Stretch shrinktube (PST) A combined telecommunication coax cable splice (Superior Cable 05/95 - 3 x 22 - BSW/NSE - 1 1/60% with RG-1 1 coax cable connector and dropwires spliced with 3M Discrete Connectors) was centered in the PST/supporting core unit, and the insert parts were wound around the coax/BSW cable and pushed up inside each end of the PST/supporting core unit A field from a radio frequency power source (80 watts power at 102 MHz frequency) was applied at each end of the PST/supporting core unit over the insert part containing the binder strip, so that the ends of the supporting core softened and the ends of the PST contracted around the cables on each side of the splice The central portion of the supporting core remained intact to provide a rigid protective closure over the coax/BSW splices After cooling, hand pressure could not separate the PST material from the cable sheaths Referring to Fig 12, the reference numeral 140 refers, generally, to a resistive sealed closure apparatus The resistive sealed closure apparatus 140 includes the support core 12 and the shrinkable tube 24 disposed over the support core 12 at the ends thereof Disposed around the support core 12 is a resistive wire 142, for example, a stainless steel, nickel chromium, or other suitably resistive material wire having a round, flat, oval, or rectangular cross-section The resistive wire 142 is spirally wrapped around the support core 12 at each end of the support core 12, and retained thereto, for example, via a double-sided adhesive foam tape 25 that may be wrapped around the support core 12 prior to wrapping the resistive wire 142. A next layer of foam tape 25 is placed over the resistive wire 142, and disposed around the support core 12 over the resistive wire 142 is a fiberglass cloth 144 A shrinkable tube 24 is then disposed over the fiberglass cloth 144 The shrinkable tube 24 may cover only portions, such as end portions, or the entire shrinkable tube 24, as desired The fiberglass cloth 144 insulates the resistive wire 142 from the shrinkable tube 24 and serves to concentrate heat from the resistive wire 142 when supplied with direct or alternating current sufficient for melting or softening the ends of the support core 12 Alternately, the wire can be coated, imbedded or laminated in a strip of suitable sealant material such as polyethylene or polyethylene elastomer
The resistive sealed closure apparatus 140 forms a sealed closure around a section of cable (not shown) upon resistive heating via the resistive wire 142 to melt or soften the support pipe 12 The melting or softening of the support pipe 12 allows the shrinkable tube 24 to cause the support pipe to collapse upon and bind to the outer jacket of the cable, in a manner like those previously described An example of a sealed closure formed by resistive heating follows A supporting pipe assembly was prepared as has been described in other examples herein, using Pelican Nichrome 60 Resistance Wire on a six (6) inch supporting pipe (one inch outside diameter, one-eighth inch wall thickness) and two (2) inch 3M 4630 Pull-N-Shrink tubes (PST) over each end of the supporting pipe Separately, two six (6) inch sections of three (3) pair twenty-two (22) gauge telecommunication cable (Superior 3x22 - 05/94) were held together with a 3M 4464 Shield Bond connector in a butt configuration (i e , cables are aligned with their ends side-by-side in the same direction) with one wire pulled from one cable to allow pressurized air to enter A flexible film member insert, comprised of low density polyethylene film (0 04 inch thickness, one half inch wide), was wrapped tightly around the cables and pushed up into one end of the supporting pipe
The supporting pipe assembly was then bonded to the two cables and the flexible film member insert by using a power source to heat the nichrome wire The heating caused the polyethylene to soften and flow around the cables and the inside of the PST This allowed the pressure of the PST to cause collapse of the supporting pipe around the cables, forming a sealing bond
Then, the nichrome wire was heated to soften the open end of the supporting pipe assembly, so that it would flow together from the pressure of the PST to seal the open end The central position of the supporting pipe assembly did not soften and served as a protected closure over the cables
After cooling, heat shrink sleeves were placed over each end of the cables, with one sleeve equipped with an air fitting on the cable with the wire removed The cable was pressurized with four (4) psi and placed inside a water tank for three (3) days Then, the pressure was increased to fifteen (15) psi for twenty-four (24) hours without any leaks detected
Alternatively, the shrinkable tube 24 may be placed over the entire support pipe 12, as well as the resistive wires 142, the foam tape layers, and the fiberglass cloth 144 Such an arrangement, upon resistive heating, serves to collapse the entire length of the support pipe 12 and shrinkable tube 24 onto the cable and to bond them with the cable over that entire length
Another example of a sealed closure formed by resistive heating follows
A supporting pipe assembly was prepared using a six (6) inch supporting pipe (one-inch outside diameter, one-eighth inch wall thickness) with two (2) inch 3M 4629 Pull-N-Shrink Tubing over one end Dow Engage™ 7090329-2 (available from the Dow Chemical Company, Midland, Michigan) was used as the sealing material and was prepared as follows A film of Engage™ (approximately 3 inches by 4 inches with a thickness of 1 175 inch) was heat-pressed to a thickness of 1050 inch using a metal mold of the same thickness Next, nichrome 80 wire ribbon (Pelican Wire Company) 125 inch wide and 005 inch thick was soldered onto the Engage™ material in a rectangular block pattern fitting inside a border having dimensions of 2 25 inches by 1 inch Next, an Engage™ piece of identical size was placed over this piece and the two were heat pressed to a thickness of
1050 inch The material was then allowed to cool and was trimmed to a final size of 2 375 inches by 1 inch
Separately, two six (6) inch sections of three (3) pair twenty-two gauge telecommunication cable (Superior 3x22) were held together with a 3M 4464 Shield Bond connector in a butt configuration (cables aligned with their ends side- by-side in the same direction) The Engage™ film member was wrapped around the cables and pushed up into the end of the pipe having the PST The supporting pipe assembly was then bonded to the two cables (and the flexible Engage I film member insert) by using a power source to heat the nichrome ribbon This heat caused the Engage11"1 material to soften and flow around the cables In addition, the pipe end was softened, allowing the pressure of the PST to cause contraction of the supporting pipe around the cables, forming a sealing bond
A heat shrink end cap fitted with an air valve was used to seal the open end of the pipe The central position of the supporting pipe assembly did not soften and served as a protective closure over the cables
After cooling, heat shrink sleeves were fitted over each end of the cables The pipe assembly was pressurized with four (4) pounds per square inch and placed inside a water tank for four (4) days The pressure was then increased to fifteen (15) psi for twenty-four (24) hours without any leaks
Although illustrative embodiments of the invention have been shown and described, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention

Claims

What is Claimed is:
1. A kit for sealed closure of a cable of the type having a low surface energy outer jacket, comprising: a support core capable of housing the cable; and a bondable material, locatable between the support core and the outer jacket, for fusion bonding of the support core, the bondable material and the outer jacket; wherein fusion bonding seals the cable with the support core.
2. The kit of claim 1, further comprising a shrinkable tube covering the support core.
3. The kit of claim 1, wherein the bondable material is a susceptor composite binder strip comprised of a bindable agent and susceptor material.
4. The kit of claim 1, wherein the bondable material is a bindable agent and resistive wires.
5. The kit of claim 1, wherein the fusion bonding is achieved by induction heating.
6. The kit of claim 1, wherein the fusion bonding is achieved by resistive heating.
7. A sealed closure for a cable of the type having a low surface energy outer jacket, comprising: a support core for housing the cable; and a bondable material between the support core and the outer jacket of the cable; wherein the support core, the bondable material, and the outer jacket are fused, sealing the cable with the support core.
8 The sealed closure of claim 7 further comprising a shrinkable tube covering the support core and fused with the support core, the bondable material, and the outer jacket, sealing the cable with the support core and the shrinkable tube
9 The sealed closure of claim 7, wherein the bondable material is a susceptor composite binder strip comprised of a bindable agent and susceptor material
10 The sealed closure of claim 7, wherein the bondable material is a bindable agent and resistive wires
1 1 The sealed closure of claim 7, wherein the fusion is achieved by induction heating.
12 The sealed closure of claim 7, wherein the fusion is achieved by resistive heating
13 A method for sealing closure of a cable having a low surface energy outer jacket, comprising the steps of housing the cable within a support core, and bonding the support core to the cable
14 The method of claim 13, further comprising the step of covering the support core with a shrinkable tube
15 The method of claim 13, wherein the step of bonding is performed by induction heating
16 The method of claim 13, wherein the step of bonding is performed by resistive heating
17. The method of claim 13, further comprising the step of locating a bondable material between the support core and the cable.
18. A kit for sealed closure of a cable of the type having a low surface energy outer jacket, comprising: a tubular support core having a longitudinal split to allow the tubular support core to be placed around the cable; a first bondable material locatable at the longitudinal split to allow the longitudinal split of the tubular support core to be re-joined; and a second bondable material, locatable between the support core and the outer jacket, for fusion bonding of the tubular support core, the bondable material, and the outer jacket; wherein fusion bonding seals the cable with the support core.
19. The kit of claim 18, further comprising a shrinkable tube covering the support core.
20. The kit of claim 18, wherein the first bondable material is a susceptor composite binder material comprised of a bindable agent and susceptor material and an electrical conductor adjacent the longitudinal split.
21. The kit of claim 18, wherein the second bondable material is a susceptor composite binder strip comprised of a bindable agent and susceptor material.
22. A sealed closure for a cable of the type having a low surface energy outer jacket, comprising: a tubular support core placed around the cable, the tubular support core has a longitudinal split; a first bondable material at the longitudinal split for re-joining the longitudinal split of the tubular support core, and a second bondable material between the support core and the outer jacket of the cable, wherein the longitudinal split is re-joined by the first bondable material and the tubular support core, the second bondable material, and the outer jacket of the cable are fused, sealing the cable with the support core
23 The sealed closure claim 22, further comprising a shrinkable tube coveπng the tubular support core
24 The sealed closure of claim 22, wherein the first bondable material is a susceptor composite binder material comprised of a bindable agent and susceptor material and an electrical conductor adjacent the longitudinal split
25 The sealed closure of claim 22, wherein the second bondable material is a susceptor composite binder strip comprised of a bindable agent and susceptor material
26 A method for sealing closure of a cable having a low surface energy outer jacket, comprising the steps of placing a tubular support core having a longitudinal split around the cable, rejoining the longitudinal split, and bonding the tubular support core to the cable
27 The method of claim 26, further comprising the step of covering the support core with a shrinkable tube
28 The method of claim 26, wherein the step of rejoining is performed with an adhesive
29 The method of claim 26, wherein the step of rejoining is performed with a bondable material comprised of a bindable agent and susceptor composite flakes adjacent a loop of a resistive wire
30 The method of claim 26, wherein the step of bonding is performed with a bondable material comprised of a bindable agent and susceptor composite flakes
31 A kit for sealed closure of a hole in a low surface energy outer jacket of a cable, comprising a polymer film for wrapping around the cable, over the hole and in the vicinity of the hole along the cable, a bondable material for placing over the polymer film, wherein fusion bonding seals the polymer film and the bondable material with the outer jacket and the hole of the cable
32 The kit of claim 31, wherein the bondable material is comprised of a bindable agent and susceptor material
33 The kit of claim 3 1, wherein the fusion bonding is achieved by inductive heating
34 The kit of claim 31, further comprising a tape for wrapping over the bondable material
35 A sealed closure for repairing a hole in a low surface energy outer jacket of a cable, comprising a polymer film around the cable, over the hole and in the vicinity of the hole along the outer jacket of the cable, and a bondable material over the polymer film, wherein the polymer film and the bondable material are fused with the outer jacket and the hole of the cable
36 The sealed closure of claim 35, wherein the bondable material is comprised of a bindable agent and susceptor material
37 The sealed closure of claim 35, further comprising a tape over the bondable material, wherein the polymer film, the bondable material, and the tape are fused with the outer jacket and the hole of the cable
38 A kit for sealed closure of a cable of the type having a low surface energy outer jacket, comprising a support core capable of housing the cable, a shrinkable tube capable of covering the support core, and a resistive wire locatable on the shrinkable tube, wherein resistive heating fuses the support core and the shrinkable tube with the outer jacket of the cable, thereby sealing the cable with the support core
39 The kit of claim 38, further comprising an adhesive tape for retaining the resistive wire adjacent the shrinkable tube
40 The kit of claim 38, further comprising an insulation sheet disposable over the resistive wire and around the shrinkable tube, for concentrating resistive heating by the resistive wire at the shrinkable tube, the support core, and the outer jacket
41 A sealed closure for a cable having a low surface energy outer jacket, comprising a support core for housing the cable, a shrinkable tube covering the support core, and a resistive wire wrapped around the shrinkable tube, wherein the support core and the shrinkable tube are fused with the outer jacket of the cable by resistive heating via the resistive wire
42 The sealed closure of claim 41, further comprising an adhesive tape for adhering the resistive wire to the shrinkable tube
43 The sealed closure of claim 41, further comprising an insulation sheet over the resistive wire for concentrating the resistive heating by the resistive wire.
44 A method for sealed closure of a cable having a low surface energy outer jacket, comprising the steps of. housing the cable within a support core, wrapping a resistive wire around the support core, covering the support core with a shrinkable tube, and supplying current to the resistive wire to create heat, wherein the support core and the shrinkable tube are fused with the outer jacket of the cable
45 An article for sealing a longitudinal section of a cable, said article comprising, a thermoplastic elongate support structure having an internal surface and an external surface and opposite ends, said external surface surrounded by an expanded elastomeric element, said internal surface enclosing an elongate chamber open at said opposite ends, said chamber having a diameter sufficient to accommodate said section of said cable, said thermoplastic support structure, upon heating, capable of providing conformable bonding sealant to bond said elastomeric element about said cable section
46 The kit of claim 18, further comprising a resistance wire located in the vicinity of the longitudinal split, wherein the resistance wire, when supplied with current, provides heating to allow the longitudinal split to be re-joined
47 The sealed closure of claim 22, further comprising a resistance wire located in the vicinity of the longitudinal split, wherein the resistance wire, when supplied with current, generates heat to re-join the longitudinal split
48. The method of claim 26, wherein the step of rejoining is performed with a resistance wire in the vicinity of the longitudinal split, wherein the resistance wire generates heat when supplied with current
49 The kit of claim 38, wherein the support core is tubular and has a longitudinal split to allow the support core to be placed around the cable
50 The method of claim 44, further comprising the steps of longitudinally splitting the support core to allow the support core to be placed around the cable; and re-joining the longitudinal split of the support core
51 A kit for sealed closure of a cable of the type having a low surface energy outer jacket, comprising a tubular support core having a longitudinal split to allow the tubular support core to be placed around the cable, and a resistance wire locatable at the longitudinal split, wherein the resistance wire, when supplied with current, generates heat to fusingly re-join the longitudinal split
52 A sealed closure for a cable of the type having a low surface energy outer jacket, comprising a tubular support core placed around the cable, having a longitudinal split; a resistance wire locatable at the longitudinal split, wherein the resistance wire, when supplied with current, generates heat to fusingly re-join the longitudinal split; and wherein the tubular support core and the outer jacket of the cable are fused, sealing the cable with the support core.
53. A method for re-joining a longitudinal split of a tubular support core, comprising the steps of: locating a resistance wire at the longitudinal split; pressing the tubular support core together at the longitudinal split; and supplying current to the resistance wire to generate heat for fusing the tubular support core at the longitudinal split.
PCT/US1997/003440 1996-11-15 1997-03-05 Sealed closure with support core systems and methods WO1998021796A1 (en)

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US74985796A 1996-11-15 1996-11-15
US08/749,857 1996-11-15

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EP1795123A4 (en) * 2004-09-01 2009-09-30 Olympus Corp Antenna unit and method for manufacturing antenna unit
US10566757B2 (en) 2016-12-09 2020-02-18 Lear Corporation Method of heat shrinking a protective sleeve onto an electrical connection
EP3417513B1 (en) 2016-02-19 2020-05-13 PKC Segu Systemelektrik GmbH Method and device for sealing contact points at electrical line connections
WO2020172415A1 (en) * 2019-02-22 2020-08-27 TE Connectivity Services Gmbh Sealant repair systems and methods for outer jacket layers of cables and cable accessories
CN113715323A (en) * 2021-11-01 2021-11-30 四川久远特种高分子材料技术有限公司 Assembling equipment for cable connector

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EP1795123A4 (en) * 2004-09-01 2009-09-30 Olympus Corp Antenna unit and method for manufacturing antenna unit
EP3417513B1 (en) 2016-02-19 2020-05-13 PKC Segu Systemelektrik GmbH Method and device for sealing contact points at electrical line connections
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CN113715323B (en) * 2021-11-01 2022-01-04 四川久远特种高分子材料技术有限公司 Assembling equipment for cable connector

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