EP3218975A1 - Environmental cable seal structure - Google Patents

Abstract

A cable seal structure (10) for sealing a cable (12) within a duct (14) includes a pouch (16) configured to receive a pressurizing fluid for inflating the pouch (16) around the cable (12). The pouch (16) includes a valve structure (34) with a valve opening (32). The pouch (16) is configured such that when the pouch (16) is wrapped around the cable (12) ready for inflation, at least a portion (54) of the pouch (16) does not circumferentially extend all the way around the cable (12). At least a portion of the valve structure (34) overlaps with the portion (54) of the pouch (16) that does not extend circumferentially all the way around the cable (12).

Description

ENVIRONMENTAL CABLE SEAL STRUCTURE

Cross Reference to Related Application

This application claims the benefit of U.S. Provisional Patent Application Serial No. 62/078,560, filed November 12, 2014, the disclosure of which is hereby incorporated by reference in its entirety.

Background

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.

The reason that 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. For example, 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. Also, when a branch- out between two or more cables is to be sealed, it will generally be necessary to convert their combined concave cross-section to a convex shape that can be enclosed by, say, a rigid wrap-around or other casing or by half-shells or a dimensionally recoverable

(generally heat-shrinkable) sleeve.

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.

Other patent specifications disclosing hollow envelopes for sealing include European patent application publication number 0100228, which 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.

While many of the articles disclosed in the above specifications are able to provide satisfactory seals, some problems remain. For example, the use of curing or otherwise setting materials may prevent or make difficult subsequent removal of the article, and simple gas pressurization of a seal will generally mean that the article has a short lifetime due to leaks or gas-diffusion. Also expensive, cumbersome, easily damaged and corrodable metal valves are required that protrude from the articles.

Summary

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.

According to another aspect of the disclosure, 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.

According to yet another aspect, 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.

A variety of additional inventive aspects will be set forth in the description that follows. The 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.

Brief Description of the Drawings

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; and

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. Detailed Description

Referring to FIGS. 1-8, 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

substantially non-stretchable, walls 18 between which a pressurizing fluid such as air may be introduced. 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. In the depicted examples, 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. When the desired internal pressure is reached, the tube 30 may be simply withdrawn, allowing the internal pressure to automatically close the hole or opening 32.

It is desirable that inflation be not too rapid since the cable sealing structure 10 itself, and any other sealing material carried thereon (e.g., mastic tape 24), must deform properly into sealing engagement with the cable 12 and the duct 14. 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. According to certain embodiments, 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. According to certain embodiments, 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.

Further examples of materials and methods for forming a suitable pouch for practicing the inventive aspects of the present disclosure are fully detailed in U.S. Patent Nos. 5,562,295 and 5,979,909, the entire disclosures of which are incorporated herein by reference.

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. It should be noted that 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.

When the fill tube 30 is withdrawn from the hole 32 by pulling, internal pressure forces some of the sealing material 40 through the hole 32 to ensure a tight seal.

The pouch or envelope 16 defining the cable sealing structure 10 is shown in FIGS. 1 and 2 in an uninflated state. As shown, according to the inventive aspects of the disclosure, 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. As shown, 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.

Thus, according to one example embodiment, the pouch 16 defines a non- rectangular uninflated shape. According to another example embodiment, the pouch 16 defines a trapezoidal uninflated shape.

According to the inventive aspects of the cable sealing structure 10, 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. According to the inventive aspects, 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.

As shown in FIGS. 1-3 and 6-8, at least a portion of the valve structure 34 is positioned between the cut-outs 52 when viewing the pouch 16 along a direction transverse to the longitudinal axis 48.

As noted above, when the cable sealing structure 10 is installed around the cable 12, 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.

Even though the disclosure provides various cable sealing structure configurations, sealing materials, and methods of manufacture and/or installation relating to environmental sealing or blocking, other configurations, materials, or methods within the spirit of the disclosure may be utilized.

Although in the foregoing description, terms such as "top," "bottom," "front," "back," "right," "left," "upper," and "lower" may have been used for ease of description and illustration, no restriction is intended by such use of the terms. The devices described herein can be used in any orientation, depending upon the desired application.

Having described the preferred aspects and embodiments of the present disclosure, modifications and equivalents of the disclosed concepts may readily occur to one skilled in the art. However, it is intended that such modifications and equivalents be included within the scope of the claims which are appended hereto.

LIST OF REFERENCE NUMERALS AND CORRESPONDING FEATURES:

10- Cable sealing structure

12- Cable

14- Duct

16- Envelope/pouch

18- Wall

20- Annular gap

22- Attachment structure

24- Mastic tape

26- First side

28- Second side

30- Fill tube

32- Hole/opening

34- Valve structure

36- Flap

38- Internal pocket

40- Sealing material/gel

42- Hole of flap

44- First end

46- Second end

48- Longitudinal axis

50- Corner

52- Cut-out

54- Portion of pouch that does not circumferentially extend all the way around the cable

56- Fully cylindrical portion of pouch

58- Mastic tape

Claims

Claims:

1) A cable seal structure (10) for sealing a cable (12) within a duct (14), the cable seal structure (10) comprising:

a pouch (16) configured to receive a pressurizing fluid for inflating the pouch (16) around the cable (12), the pouch (16) including a valve structure (34) including a valve opening (32), wherein the pouch (16) is configured such that when the pouch (16) is wrapped around the cable (12) ready for inflation, at least a portion (54) of the pouch (16) does not circumferentially extend all the way around the cable (12), wherein at least a portion of the valve structure (34) overlaps with the portion (54) of the pouch (16) that does not extend circumferentially all the way around the cable (12).

2) A cable seal structure (10) according to claim 1, wherein first and second

longitudinal sides (26, 28) of the pouch (16) are fixed together around the cable (12) with an attachment structure (22).

3) A cable seal structure (10) according to claim 2, wherein the attachment structure (22) includes mastic tape (24).

4) A cable seal structure (10) according to claim 1, wherein the valve opening (32) is surrounded by mastic tape (58).

5) A cable seal structure (10) according to claim 1, wherein the entire valve structure (34) overlaps with the portion (54) of the pouch (16) that does not

circumferentially extend all the way around the cable (12).

6) A cable seal structure (10) according to claim 1, wherein the valve structure (34) includes a sealing gel (40) that is configured to seal the valve opening (32) when a fill tube (30) is removed from the pouch (16) after inflation.

7) A cable seal structure (10) according to claim 1, wherein the pouch (16) defines a wall (18) including a laminate of a metallic layer and a polymeric layer. A cable seal structure (10) for sealing a cable (12) within a duct (14), the cable seal structure (10) comprising:

a pouch (16) configured to receive a pressurizing fluid for inflating the pouch (16) around the cable (12), the pouch (16) including a valve structure (34) including a valve opening (32), wherein the pouch (16) defines a generally flat uninflated shape having a first end (44) separated from a second end (46) along a longitudinal axis (48) of the pouch (16), the pouch (16) further defining a first side (26) and a second side (28) separated by the first and second ends (44, 46), wherein corners (50) defined between the first end (44) and each of the first and second sides (26, 28) of the pouch (16) are relieved so as to define cut-outs (52) at the first end (44) at each of the first and second sides (26, 28).

A cable seal structure (10) according to claim 8, wherein the pouch (16) defines a non-rectangular uninflated shape.

A cable seal structure (10) according to claim 9, wherein the pouch (16) defines a trapezoidal uninflated shape.

A cable seal structure (10) according to claim 8, wherein at least a portion of the valve structure (34) is positioned between the cut-outs (52) when viewing the pouch (16) along a direction transverse to the longitudinal axis (48).

A cable seal structure (10) according to claim 11, wherein the entire valve structure (34) is positioned between the cut-outs (52) when viewing the pouch (16) along a direction transverse to the longitudinal axis (48).

A cable seal structure (10) according to claim 8, wherein the valve structure (34) includes a sealing gel (40) that is configured to seal the valve opening (32) when a fill tube (30) is removed from the pouch (16) after inflation.

A cable seal structure (10) according to claim 8, wherein the pouch (16) defines a wall (18) including a laminate of a metallic layer and a polymeric layer. A method of sealing a cable (12) within a duct (14), the method comprising:

wrapping a pouch (16) configured to receive a pressurizing fluid for inflating the pouch (16) around the cable (12) such that at least a portion (54) of the pouch (16) does not circumferentially extend all the way around the cable (12); fixing first and second longitudinal sides (26, 28) of the pouch (16) together around the cable (12) with an attachment structure (22);

inserting the cable (12) with the pouch (16) into a duct (14);

filling the pouch (16) with the pressurizing fluid via a fill tube (30) through a valve opening (32) of a valve structure (34) of the pouch (16), wherein the valve structure (34) is positioned to at least partially overlap with the portion (54) of the pouch (16) that does not circumferentially extend all the way around the cable (12); and

removing the fill tube (30).

A method according to claim 15, further comprising sealing the valve opening (32) with a sealing gel (40) after the fill tube (30) is removed from the valve opening (32).

A method according to claim 15, further comprising inserting the fill tube (30) into the valve opening (32) before filling the pouch (16) with the pressurizing fluid.

A method according to claim 15, wherein the pressurizing fluid is air.

A method according to claim 15, wherein the attachment structure (22) includes mastic tape (24).

A method according to claim 15, further comprising applying lubrication on the pouch (16) prior to insertion into the duct (14).

A system including a cable seal structure (10) according to any of claims 1-14 and a telecommunications cable (12) around which the cable seal structure (10) is wrapped.