Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
  • H02G15/00—Cable fittings
  • H02G15/013—Sealing means for cable inlets
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L5/00—Devices for use where pipes, cables or protective tubing pass through walls or partitions
  • F16L5/02—Sealing

Definitions

• the present disclosure relates to environmental sealing of substrates such as cables or pipes, particularly within a duct or a splice case. This may be done to prevent water, gas or other contaminants from passing along a duct into a manhole, etc., or to protect a cable splice from the environment.
• the inventive aspects of the disclosure will be described primarily in terms of a duct seal, but the inventive aspects are also applicable to other instances of sealing, including splice cases, pipe protection and grommets, etc.
• a seal (rather than an adhesive bond of no significant thickness) may be required is a disparity in size or shape between the substrate to be sealed and some other object such as a housing within which it lies.
• a duct may be from several millimeters to several centimeters larger than the cable or other substrate that it carries, an oval cable may lie within a circular duct, or the installed size of a splice case housing may be larger than the spliced cables within it.
• Such seals have usually been formed by the use of a conformable sealing member, for example an O-ring, or the use of a mass of sealant or a hot-melt adhesive. While these seals in general work in a satisfactory manner, problems sometimes occur. For example, by their nature, conformable sealing members have a low modulus and especially where they are used to fill large voids, may have a tendency to creep over extended periods of time. Also, leak paths may occur if it has not been possible to introduce sufficient heat into a hot-melt adhesive to melt it. It is, for example, difficult to introduce heat into a duct. Difficulties may also arise due to the materials needed for ducts and cables, which may be incompatible. Cables are often made of polyethylene or lead, and ducts of polyvinyl chloride, steel, or cement which may be dirty or crumbly and difficult to clean.
• a widely used duct seal disclosed in British patent number 1594937, comprises a hollow body member provided on its inner and/or outer surface with a plurality of spaced-apart flanges, each flange extending away from and around said surface and at least a portion of the flange remote from said surface being deformable, but only at an elevated temperature, and at least part of said surface(s) and/or the surface of the flanges having a sealant thereon.
• European patent application publication number 0179657 discloses a duct seal, especially for sealing about four cables, which contains a spring which, when operated, radially expands the part of the duct seal that is to seal to the duct.
• the cables are sealed by heat-shrink outlets of the duct seal.
• the spring is operated after heating the part of the duct seal in which it lies. Heating may soften the material of the seal and activate an adhesive.
• European patent application publication number 0152696 discloses an assembly for sealing an aperture (such as that between a duct and a cable it carries) which comprises a flexible envelope that is arranged to be wrapped on itself for insertion into the aperture, the envelope having an opening therein for receiving an expansible or expanding filler material, for example a curable foam, for expanding the envelope, a container containing said expansible filler material and means arranged to connect the container to the envelope to conduct the filler thereto for effecting expansion of the envelope, characterized in that an adhesive or sealant is located on or associated with at least part of the outer surface of the envelope.
• an adhesive or sealant is located on or associated with at least part of the outer surface of the envelope.
• European patent application publication number 01002208 discloses a method of forming a seal between at least one elongate object and a surface surrounding the object which comprises: (a) positioning between the object and the surface, a flexible envelope containing a void- filling composition which is capable of undergoing a change from a state of lower viscosity to a state of higher viscosity; (b) deforming at least part of the envelope, thereby causing the void-filling composition to conform to the object and to the surface; and (c) causing said change from lower to higher viscosity.
• European patent application publication number 0210807 discloses a double-walled article, two of which may be used one around the other to form a duct seal, in the form of a tube having a small volume filling of a friction reducing liquid (preferably of high boiling point and low vapor pressure) or solid between its two walls.
• the article is able to revolve over a substrate by shear between its two walls to provide environmental or electrical protection.
• British patent number 2006890 discloses a seal comprising a container formed from resilient plastic sheets and partially filled with a liquid which is provided between a protective tube in a wall and insulation layer around a pipe.
• the container is of substantially toroidal shape and permits the pipe to move axially and radially whilst maintaining a seal between the insulation layer and the tube.
• U.S. Pat. No. 3,038,732 discloses an inflatable seal bushing for sealing a pipeline casing, which comprises a hollow resilient means having an inflated configuration to match the inside surface of said casing and to contact the outside surface of the pipe of said pipeline, means for introducing a fluid into said hollow resilient means to inflate same, and a plurality of angularly disposed relatively solid spacer means integral with said hollow resilient means and transverse thereto for centering and supporting said pipe within said casing, each of said spacer means having a passage therethrough for providing liquid communication in the hollow interior of said hollow resilient means.
• U.S. Pat. No. 2,816,575 discloses an apparatus for laying a pipe employing inflated annular sealing rings.
• U.S. Pat. No. 3,339,011 discloses a pneumatically sealed cable splice case comprising a longitudinally split sealable cylindrical casing having means within and adjacent to each of its longitudinal ends to retain and space apart a pair of end wall panels, each end wall panel including two semi-circular disc portions having rounded outer edges and inner edges including aligned cut-outs therealong, whereby cables may enter said casing through said aligned cutouts, and inflatable seal means confined between each of said pair of panels of said end walls and having openings aligned with said panel openings, said inflatable means being expandable, when so confined, against such cables passed through said end wall openings, characterized in that said end walls are removable from the said means to retain them, and said semi-circular disc portions are pivotally pinned to each other with their cut-outs presented together to form said openings of said panels, whereby said semi-circular disc portions may be pivotally opened apart for placement about said conduits.
• An inflatable packing device for insertion between mating surfaces of the hub and spigot ends of a pipe joint is disclosed in British patent number 1077314.
• a hollow- walled sleeve into which fluid is to be injected for heat-insulation of ducts is disclosed in British patent number 1421960.
• An inflatable closure member having a sealing material thereof, and used for sealing cables is disclosed in British patent number 2028601.
• U.S. Pat. No. 907,136 discloses a packing for pipe joints formed by folding an open mesh fabric and applying a glue, etc.
• An aspect of the present disclosure relates to a cable seal structure for sealing a cable within a duct.
• the cable seal structure includes a pouch or envelope configured to receive a pressurizing fluid, such as air, for inflating the pouch around the cable.
• the pouch includes a valve structure with a valve opening.
• the pouch is configured such that when the pouch is wrapped around the cable ready for inflation, at least a portion of the pouch does not circumferentially extend all the way around the cable. At least a portion of the valve structure overlaps with the portion of the pouch that does not extend circumferentially all the way around the cable.
• a cable seal structure for sealing a cable within a duct includes a pouch configured to receive a pressurizing fluid for inflating the pouch around the cable, the pouch including a valve structure including a valve opening, wherein the pouch defines a generally flat uninflated shape having a first end separated from a second end along a longitudinal axis of the pouch, the pouch further defining a first side and a second side separated by the first and second ends. Corners defined between the first end and each of the first and second sides of the pouch are relieved so as to define cut-outs at the first end at each of the first and second sides.
• the disclosure relates to a method of sealing a cable within a duct.
• the method includes wrapping a pouch configured to receive a pressurizing fluid for inflating the pouch around the cable such that at least a portion of the pouch does not circumferentially extend all the way around the cable, fixing first and second longitudinal ends of the pouch together around the cable with an attachment structure, inserting the cable with the pouch into a duct, filling the pouch with the pressurizing fluid via a fill-tube through a valve opening of a valve structure of the pouch, wherein the valve structure is positioned to at least partially overlap with the portion of the pouch that does not circumferentially extend all the way around the cable, and removing the fill-tube.
• inventive aspects can relate to individual features and combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.
• FIG. 1 illustrates a cable sealing structure having features that are examples of inventive aspects in accordance with the present disclosure shown in an uninflated configuration
• FIG. 2 illustrates the cable sealing structure of FIG. 1 with further sealing structures in the form of mastic tape applied thereto;
• FIG. 3 illustrates the cable sealing structure of FIG. 2 in a folded configuration
• FIG. 4 is a cross-section of the valve structure of the cable sealing structure of FIGS. 1-3, bisecting the valve structure along a longitudinal axis of the cable sealing structure;
• FIG. 5 is an exploded view illustrating the features of the valve structure that are positioned within the internal pocket of the cable sealing structure
• FIG. 6 illustrates the cable sealing structure of FIG. 3 being wrapped around cabling and being inserted into a duct
• FIG. 7 illustrates the cabling with the cable sealing structure of FIG. 6 fully inserted into the duct, ready for inflation
• FIG. 8 illustrates the opposing side of the duct relative to that shown in FIG. 7, showing the cutouts defined by the cable sealing structure.
• the present disclosure is directed generally to a cable sealing structure 10.
• the cable sealing structure 10 is configured to be used as a duct seal, for sealing an annular gap 20 between a cable 12 and a duct 14.
• the sealing structure 10 includes an envelope or pouch 16 that has flexible, and preferably
• the sealing structure 10 after being placed around a cable 12 and inserted into a duct 14 with the cable 12, is configured to be brought from an uninflated state to an inflated state for sealing the annular gap 20 between the cable 12 and the duct 14.
• the sealing structure 10 may be wrapped around the cable 12 and fixed thereto with an attachment structure 22.
• the attachment structure 22 is provided in the form of a piece of mastic tape 24, which is used to attach together a first side 26 and a second side 28 of the pouch 16 around the cable 12, as will be described in further detail below.
• the mastic tape 24 may also fill the irregularities in the surface of the duct 14.
• the inflation of the envelope or pouch 16 may be carried out by inserting a fill tube 30 through a hole or opening 32 defined on an exterior wall 18 of the pouch 16 and attaching the tube 30 to a source of pressurizing fluid. If the cable sealing structure 10 is supplied with a fill tube 30 from the factory, then the tube 30 is simply attached to a source of pressurizing fluid.
• the pressurizing fluid is preferably compressible air or nitrogen or other inert gas.
• the tube 30 may be simply withdrawn, allowing the internal pressure to automatically close the hole or opening 32.
• a hand pump such as a bicycle pump, an electric pump, a pressurized gas cylinder or other suitable pressurizing mechanisms may be used. More powerful pumps may desirably be used with a pressure reducer.
• the walls 18 of the cable sealing structure 10 that define the pouch 16 may be flexible in general, and thus able to conform to cables of various sizes and/or of irregular shape.
• the walls 18 may comprise multiple layers, for example one serving to retain the fluid and one to provide mechanical strength, for example, tensional strength against internal pressure, tear-strength or puncture resistance.
• the walls 18 may comprise a first layer of metal (or metallized plastics material or metal-coated plastics material), optionally with which the fluid is in contact, and a second strengthening layer such as high density polyethylene.
• Each wall 18 of the pouch 16 may comprise, for example, a laminate of a metal film and a layer of plastic material on either side. Such plastic layers may allow the wall to be heat-welded to itself to form the envelope 16.
• a flap weld or bond which may be under shear rather than peel when the article is inflated, preferably extends along the length of the sealing structure 10 where the sealing structure 10 defines a generally cylindrical shape when inflated and the first and second longitudinal sides 26, 28 are attached together.
• the hole 32 through which the fill tube 30 is inserted through may be provided as part of a valve structure 34 for the pouch 16.
• the valve structure 34 may include a flap 36 that is positioned within an internal pocket 38 defined by the pouch 16.
• a sealing material or gel 40 optionally may be provided between the wall 18 that defines the hole 32 and the flap 36.
• the flap 36 acts as a barrier to prevent the sealing gel 40 from sticking the wall 18 to an opposing wall 18.
• the flap 36 may also have a hole 42 therethrough, as shown, in order to allow a fill tube 30 to pass through the gel 40 and the flap 36 generally perpendicular to the surface of the outer wall 18.
• FIG. 4 shows the sealing gel 40, the flap 36, and the wall 18 in their assembled configuration.
• the hole 42 of the flap 36 may be provided at other locations on the flap 36, for example, so as to allow the fill tube 30 to pass into the internal pocket 38 defined by the pouch 16 at a smaller angle than a perpendicular angle to the surface wall 18.
• the pouch or envelope 16 defining the cable sealing structure 10 is shown in FIGS. 1 and 2 in an uninflated state.
• the pouch 16 in the uninflated state, defines a generally flat structure.
• the pouch 16 defines a first end 44 separated from a second end 46 along a longitudinal axis 48 defined be the pouch 16.
• the first side 26 and the second side 28 of the pouch 16 are separated by the first and second ends 44, 46.
• corners 50 defined between the first end 44 and each of the first and second sides 26, 28 are relieved so as to define cutouts 52 at the first end 44 at each of the first and second sides 26, 28.
• the pouch 16 defines a non- rectangular uninflated shape. According to another example embodiment, the pouch 16 defines a trapezoidal uninflated shape.
• cutouts 52 defined by the pouch 16 function to provide space for the valve structure 34 of the pouch 16.
• the pouch 16 is configured such that when the pouch 16 is wrapped around a cable 12, at least a portion 54 of the pouch 16 does not circumferentially extend all the way around the cable 12 as shown in FIG. 8.
• at least a portion of the valve structure 34 of the pouch 16 is positioned within the portion 54 of the pouch 16 that does not extend circumferentially all the way around the cable 12, such that there is room for the valve structure 34 including the flap 36 and the sealing material 40 when the pouch 16 is fully inflated. Otherwise, in a pouch that has a complete rectangular configuration, wherein the entirety of the pouch (along the longitudinal direction) extends fully circumferentially around the cable 12, there might not be sufficient space to accommodate the valve structure between the duct 14 and the cable 12.
• the cut-outs 52 provide spacing for the cable 12 to be able to move when the pouch 16 is being inflated as the valve structure 34 starts pushing against the cable 12 from the opposite direction. While the cut-outs 52 provide room for the cable 12 and the valve 34 positioned adjacent thereto, a fully cylindrical portion 56 (rectangular when uninflated) of the pouch 16 still provides a tight seal with the duct 14.
• valve structure 34 is positioned between the cut-outs 52 when viewing the pouch 16 along a direction transverse to the longitudinal axis 48.
• the pouch 16 may be folded over the cable 12 (the first and second longitudinal sides 26, 28 may be brought together), and the first and second sides 26, 28 may be attached together using the attachment structure 22 such as a piece of mastic tape 24.
• the mastic tape 24 may also fill the irregularities in the surface of the duct 14 to provide a perfect seal.
• a similar piece of mastic tape 58 may be used to surround the hole 32 defined by the valve structure 34. In this manner, if some sealing material 40 leaks out of the hole 32 prior to tube 30 withdrawal, the sealing material 40 may be contained and not reach unwanted areas.
• Lubrication material may be applied to the surface of the mastic tape 24, 58 to facilitate initial insertion of the cable sealing structure 10 (and the cable 12) into the duct 14.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Cable Accessories (AREA)

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• 2015
  • 2015-11-12 WO PCT/EP2015/076472 patent/WO2016075258A1/en active Application Filing
  • 2015-11-12 EP EP15794179.0A patent/EP3218975A1/de not_active Withdrawn

Non-Patent Citations (2)

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