Protective member

Abstract

Provided is a novel protective member (10) that separates a plurality of cables which pass through a structure (50) embedded in the ground and which is capable of providing protection from unnecessary electromagnetic waves. A protective member (10) according to the present disclosure covers a cable disposed within a structure (50) that is embedded in the ground, said protective member (10) being characterized by: comprising a conductive material covering the cable from the radially outer side thereof at least a prescribed distance that is along the lengthwise direction of the cable and that is from a cable hole (53a), which is provided in a wall part of the structure (50) and through which the cable passes, and toward the inside of the structure (50); having flexibility at least at the time of determination of the shape thereof; and having shape retainability at least after the determination of the shape thereof.

Description

Protective materials

[0001] This disclosure relates to protective members.

[0002] According to the Wire Telecommunications Equipment Ordinance, underground electric wires must be placed at a distance of more than 0.3 m from underground high-current electric wires. When it is unavoidable to place an underground electric wire at a distance of 0.3 m or less from an underground high-current electric wire, a partition wall must be provided between the two electric wires, and thus conventionally, protection has been provided using flexible pipes or the like (for example, Non-Patent Document 1, etc.).

[0003] Tokyo Metropolitan Government Bureau of Construction, "Tokyo Electric Cable Utility Tunnel Maintenance Manual," [online], [accessed August 20, 2024], Internet: <https: / / www.kensetsu.metro.tokyo.lg.jp / content / 000048552.pdf>

[0004] However, when laying a power cable (high-current underground electric cable) and a communication cable (underground electric cable) in a structure buried underground such as a manhole, if the duct opening for the power cable and the duct opening for the communication cable are adjacent to each other, it may not be possible to separate them by the required distance. In such cases, a partition wall must be installed between the two, but it is difficult to install a partition wall only in the adjacent sections inside the manhole.

[0005] Furthermore, when working in manholes or other areas where power cables are installed, it is desirable to protect the cables and create a working space to ensure the safety of workers in order to prevent breakdowns due to inadvertent contact or accidental cutting, but this is difficult to achieve with conventional cable wiring alone, and there is still room for improvement.

[0006] Therefore, in consideration of these points, the object of the present disclosure is to provide a new protective member that can separate multiple cables passing through a structure buried underground and protect them from unnecessary electromagnetic waves.

[0007] In order to solve the above problem, the protective member disclosed herein is a protective member that covers a cable placed within a structure buried underground, wherein the protective member covers the cable from the radial outside for at least a predetermined distance along the longitudinal direction of the cable from a cable hole that is provided in a wall of the structure and through which the cable passes toward the inside of the structure, includes a conductive material, and is flexible at least when the shape is determined, and has shape retention at least after the shape is determined.

[0008] According to the present disclosure, a new protective member can be provided that can separate multiple cables passing through a structure buried underground and protect them from unnecessary electromagnetic waves.

[0009] 1 is a diagram showing a state in which a protective element of the present disclosure covers a portion of a cable disposed in a structure buried underground and having a bottomed tubular shape. It is an enlarged view of the protective element in FIG. 1 , covering from the radial outside a predetermined distance along the longitudinal direction of the cable from the end of the cable hole toward the inside of the structure. It is a cross-sectional view showing a state in which a protective element divided in the circumferential direction according to a first division pattern is being attached to a cable by a first attachment method. It is a cross-sectional view showing a state in which a protective element divided in the circumferential direction according to the first division pattern has been attached to a cable by the first attachment method. It is a cross-sectional view showing a state in which a protective element divided in the circumferential direction according to the first division pattern has been attached to a cable by a second attachment method. It is a cross-sectional view showing a state in which a protective element divided in the circumferential direction according to the first division pattern has been attached to a cable by the second attachment method. It is a cross-sectional view showing a state in which a protective element divided in the circumferential direction according to the second division pattern has been attached to a cable ... FIG. 10 is a cross-sectional view showing a state in which a protective member divided circumferentially according to a second division pattern is attached to a cable and then fixed by a second fixing method. FIG. 11 is a cross-sectional view showing a state in which a protective member divided circumferentially according to the second division pattern is attached to a cable and then fixed by a third fixing method. FIG. 12 is a view showing a state in which a protective member having a bellows structure is attached to a cable. FIG. 13 is a view showing a state in which a protective member having a mesh structure is attached to a cable. FIG. 14 is a view showing a state in which a protective member having a layer containing a conductive material formed on the outside of a base material made of thermosetting resin, ultraviolet curing resin, or curable sealant is attached to a cable.

[0010] Hereinafter, a protective member 10 according to the present disclosure that covers a portion of a cable (power cable 20) disposed within a structure 50 that is buried underground and has a cylindrical shape with a bottom will be described with reference to the drawings.

[0011] The protective member 10 according to this embodiment is a member that covers a portion of a cable (power cable 20 in the example shown in FIG. 1 ) disposed within a structure 50 buried underground. The structure 50 here is, for example, a concrete handhole, manhole, or other structure having a bottomed cylindrical shape. The vertical, horizontal, and depth directions of the structure 50 correspond to the vertical, horizontal, and depth directions of FIG. 1 and directions intersecting the plane of the page. The structure 50 includes a top wall 51, a bottom wall 52, left and right side walls 53 and 54, depth side walls 55 and 56, and a cylindrical neck 57 extending upward from the top wall 51 and forming an upper opening 57a that leads to the ground. In FIG. 1 , the foreground side wall 55 is depicted by a two-dot chain line to show the interior of the structure 50.

[0012] Ducts 61 and 62 for passing cables are connected to the side wall 53 on the left side in Fig. 1, and ends of each duct 61 and 62 communicate with cable holes 53a and 53b provided in the side wall 53, respectively. Similarly, ducts 63 and 64 for passing cables are connected to the side wall 54 on the right side in Fig. 1, and ends of each duct 63 and 63 communicate with cable holes 54a and 54b provided in the side wall 54, respectively.

[0013] As shown in FIG. 1 , a power cable 20 is passed through ducts 61 and 63. In this embodiment, the power cable 20 is an underground heavy-current electric cable as defined in the Wire Telecommunications Equipment Ordinance. Furthermore, a communication cable 30 is passed through ducts 62 and 64. The communication cable 30 adjacent to the power cable 20 must be separated from the power cable 20 by more than 0.3 m, or a partition wall must be provided between the power cable 20 and the communication cable 30 (Article 14 of the Wire Telecommunications Equipment Ordinance). In this embodiment, because the distance between the ducts 61 and 62 (i.e., the distance between the cable holes 53 a and 53 b) is 0.3 m or less, a separate partition wall must be provided between the power cable 20 and the communication cable 30 inside the structure 50 where the ducts 61 and 62 serving as partition walls are not present.

[0014] In this embodiment, as shown in FIGS. 1 and 2 , the protective member 10 radially covers a predetermined distance along the longitudinal direction of the power cable 20 from the cable hole 53 a in the side wall 53 toward the inner space S of the structure 50. The protective member 10 has a flange portion 11 at the end of the side wall 53 and is fixed to the side wall 53 with fastening members such as bolts using fixing holes 11 a provided in the flange portion 11. In this case, the predetermined distance is a distance that ensures a distance of more than 0.3 m between the power cable 20 and the communication cable 30 in the area not covered by the protective member 10 by fixing the shape of the power cable 20 with the protective member 10 over the predetermined distance in FIG. 1 . In the illustrated example, in the longitudinal region where the protective member 10 is attached, the power cable 20 is oriented in the depth direction toward the top of FIG. 1 and is fixed by a fixing member 22 that protrudes forward from the side wall 56 on the far side of the structure 50. In the illustrated example, the power cable 20 is placed and fixed on a fixing hardware. A filter member 21 is attached to the power cable 20. In this way, by determining the shape of the protective member 10 so as to separate the power cable 20 from other cables (communication cable 30 in the example of FIG. 1 ) in the longitudinal region where the protective member 10 is attached, it is possible to ensure a distance of more than 0.3 m between the power cable 20 and other cables (communication cable 30 in the example of FIG. 1 ) in regions where the protective member 10 is not provided.

[0015] As shown in Fig. 1 , the communication cable 30 is oriented downward and toward the front from the cable hole 53b in the side wall 53 toward the internal space S of the structure 50 so as to be spaced apart from the power cable 20. The communication cable 30 is fixed by a fixing member 32 that protrudes toward the back from the side wall 55 on the front side of the structure 50. In the example shown in the figure, the communication cable 30 is placed and fixed on a fixing metal fitting. A filter member 31 is attached to the communication cable 30.

[0016] 1, the protective member 10 is not provided on the communication cable 30, but the protective member 10 may also be attached to the communication cable 30. Also, a member having only some of the functions of the protective member 10 (conductivity, flexibility, or shape retention) may be attached to the communication cable 30. In particular, when the communication cable 30 is also oriented so as to be actively separated from the power cable 20 within the internal space S of the structure 50 as shown in FIG. 1, it is preferable to attach a member having shape retention to the communication cable 30 as well.

[0017] The radial direction of the protective member 10, the power cable 20, and the communication cable 30 is the direction passing through their axes and perpendicular to the axes. The radially inward direction is the direction toward the axes along the radial direction, and the radially outward direction is the direction away from the axes along the radial direction. The circumferential direction is the direction of rotation around the axes.

[0018] The protective member 10 includes a conductive material such as a metal material to suppress the influence of unwanted electromagnetic waves between the power cable 20 and other cables. Examples of conductive materials include metal materials such as copper, aluminum, nickel, and titanium, as well as alloys thereof. The conductive material may also be a magnetic ceramic material such as gold, which is a conductive ceramic such as phyllite, which is formed and fired from a powder primarily composed of iron oxide, or a conductive polymer material in which conductive particles are mixed into plastic or rubber. When the protective member 10 includes a conductive polymer material, conductive particles such as conductive carbon particles or metal particles can be used. The conductive protective member 10 can be grounded to a conduit or the like to suppress current flow to other cables.

[0019] In this embodiment, similar to the side wall 53 side, the protective member 10 covers a predetermined distance along the longitudinal direction of the power cable 20 from the cable hole 54a of the side wall 54 toward the inner space S of the structure 50 from the radially outer side.

[0020] In this embodiment, the protective member 10 can be divided at least at one location in the circumferential direction using the first division pattern or the second division pattern shown in Figures 3A to 5B, taking into account ease of attachment to the power cable 20.

[0021] 3A and 3B show an example in which a protective member 10 divided circumferentially according to a first division pattern is attached to a cable (power cable 20) by a first attachment method. Note that FIGS. 3A to 3C are cross-sectional views of the power cable 20 and the protective member 10 as viewed from the axial direction. In the first division pattern, as shown in FIG. 3A , the cylindrical protective member 10 is divided at one location in the circumferential direction in cross-section. As shown in FIG. 3A , the protective member 10 is deformed to widen the spacing between the divisions and then positioned radially outward from the power cable 20. Then, as shown in FIG. 3B , the protective member 10 is attached by deforming the protective member 10 to narrow the spacing between the divisions.

[0022] 4A and 4B show an example in which a protective member 10 divided circumferentially according to the first division pattern is attached to a cable by the second attachment method. As shown in Fig. 4A, material for the protective member 10, which is linear in cross section, is prepared in advance, and the protective member 10 is wrapped around the power cable 20 from the radially outer side, so that the protective member 10 covers the power cable 20 from the radially outer side, as shown in Fig. 4B. As a result, the cylindrical protective member 10 has a cross-sectional shape divided at one location in the circumferential direction.

[0023] 5A and 5B show an example of a technique for fixing a protective member 10 circumferentially divided by a second division pattern to a cable. As shown in FIG. 5A , the second division pattern divides the cylindrical protective member 10 in cross section at two circumferential locations. In this embodiment, the two circumferential division locations are located 180 degrees apart and facing each other in the circumferential direction. As shown in FIG. 5A , two (one set) of semicircular protective members 10 are placed radially outside the power cable 20 to form a protective member 10 circumferentially divided by the second division pattern, as shown in FIG. 5B .

[0024] In addition, when attaching the protective members 10 in the second division pattern, it is not necessarily necessary to use two (one set) of protective members 10 formed in a semicircular shape in advance. Two (one set) of protective members 10 each having half the length of the straight protective member 10 prepared in Figure 4A can be prepared, and the two (one set) of protective members 10 can be wrapped around the radial outside of the power cable 20 to form the protective member 10 in the second division pattern.

[0025] The protective member 10 can be fixed to the power cable 20 by, for example, the techniques shown in Figures 6A to 6C. For example, as shown in Figure 6A, the protective member 10 can be fixed by wrapping a cable tie 15 around the protective member 10 from the radially outer side.

[0026] 6B , for example, flange portions extending radially outward from both ends of two (one set) of protective members 10 according to the second division pattern can be provided, and the flange portions can be fastened together with fastening bolts 16 in a state where the power cable 20 is covered from the radial outside by the two (one set) of protective members 10. This allows the protective members 10 to be fixed to the power cable 20.

[0027] 6C , for example, a pair of flanges may be provided extending radially outward from the division points of the protective member 10 according to the first division pattern, and the flanges may be fastened together with fastening bolts 17 while the protective member 10 covers the power cable 20 from the radial outside. This allows the protective member 10 to be fixed to the power cable 20.

[0028] The method for fastening the protective member 10 is not limited to the above-described method. For example, instead of the fastening bolts 16, 17, a pair of snap buttons may be used for fastening, or the flange portions may be fastened together using adhesive, adhesive tape, hook-and-loop fastener, or the like.

[0029] The protective member 10 can have a bellows structure, as shown in Fig. 7, for example. This configuration allows the bellows structure to be bent into a desired shape (flexibility) and to maintain that shape (shape retention). The bellows-structured protective member 10 can have an electromagnetic wave shielding function by forming a conductive material such as a metal (copper, aluminum, nickel, titanium, etc.) on the surface of the bellows structure made of synthetic resin by plating or painting.

[0030] The method of imparting electromagnetic wave shielding functionality to a bellows structure is not limited to forming a metal layer, but may involve coating the surface with the above-mentioned magnetic ceramic material or conductive polymer material. Furthermore, the conductive material is not limited to being provided on the surface of the bellows structure, but may be provided as an intermediate layer of a multi-layered bellows structure. The bellows structure may also be formed from a material mixed with conductive powder.

[0031] When the protective member 10 is provided with a bellows structure, instead of attaching it to the power cable 20 by dividing it in the circumferential direction as shown in Figures 3A to 6C, it may be attached to the power cable 20 from the axial direction. By not dividing the protective member 10 in the circumferential direction, it is possible to suppress phase shifts in the bellows structure between the divided protective members 10.

[0032] The protective member 10 may have a mesh structure, as shown in FIG. 8 , and may be wrapped around the power cable 20 from the radially outer side. This mesh structure provides flexibility when the mesh structure portion is bent into a desired shape, and the intersections of the mesh determined by the bent shape are maintained by friction, allowing for shape retention. The protective member 10 with this mesh structure may be formed from a wire mesh made of metal (aluminum, nickel, titanium, copper, etc.) or other conductive material. Alternatively, it may be formed by coating a fiber material made of glass fiber or a synthetic resin, such as acrylic or polyvinyl chloride, with a conductive material such as metal. The mesh structure may also be formed from a material mixed with conductive powder. The conductive properties of the mesh structure can suppress electromagnetic wave radiation to other cables.

[0033] In addition, the protective member 10 may have a layer 10b containing a conductive material formed on a base material 10a made of a thermosetting resin, an ultraviolet-curing resin, or a curable sealant, or the base material 10a made of a thermosetting resin, an ultraviolet-curing resin, or a curable sealant may be configured to contain a conductive material.

[0034] 9 shows an example of a protective member 10 in which a base material 10a made of a thermosetting resin, an ultraviolet-curing resin, or a curing sealant is provided on the radially outer side of a power cable 20, and a layer 10b containing a conductive material is further provided on the outer side of the base material 10a. When the base material 10a is a thermosetting resin, the base material is bent into a desired shape in an unheated flexible state and then heated to provide shape retention. When the base material 10a is an ultraviolet-curing resin, the base material is bent into a desired shape in an unheated flexible state and then irradiated with ultraviolet light to provide shape retention. When the base material 10a is a curing sealant, the base material is bent into a desired shape in an uncured flexible state and then cured to provide shape retention.

[0035] Curable sealants include silicone-based, silylated acrylate-based, modified silicone-based, polysulfide-based, acrylic urethane-based, polyurethane-based, acrylic-based, butyl rubber-based, etc. Furthermore, depending on the curing method, they can be classified into moisture-curing types that cure by reacting with moisture in the air, dry-curing types that cure when the solvent or water evaporates and dries, and mixed reaction-curing types that cure by mixing the base agent and curing agent and causing a chemical reaction.

[0036] When the substrate 10a is a thermosetting resin, for example, a layer 10b containing a conductive material can be provided on the outside of the substrate 10a, and then the substrate can be bent into a desired shape and heated to provide shape retention. When the substrate 10a is a mixed reaction curing type curable sealant, a layer 10b containing a conductive material can be provided on the outside of the substrate 10a, and then the substrate can be temporarily fixed in a bent state into a desired shape before curing, and shape retention can be provided after curing. Alternatively, the substrate 10a alone can be bent into a desired shape, and after curing to provide shape retention, a layer 10b containing a conductive material can be provided on the outside of the substrate 10a.

[0037] When the substrate 10a is an ultraviolet-curable resin or a moisture-curable or dry-curable curable sealant, it is preferable to fold the substrate 10a alone into a desired shape, give it shape retention by curing, and then provide the layer 10b containing a conductive material on the outside of the substrate 10a, because not providing the layer 10b containing a conductive material can promote curing of the substrate 10a.

[0038] Furthermore, instead of providing the layer 10b containing a conductive material on the outside of the substrate 10a, the substrate 10a may be configured to contain a conductive material such as conductive powder.

[0039] Alternatively, after providing a layer 10b containing a conductive material on the outside of the power cable 20, a base material 10a made of a thermosetting resin, an ultraviolet curing resin, or a curable sealing material may be provided on the outside of the layer 10b and then cured.

[0040] 7 or the mesh structure shown in Fig. 8 may be combined with a thermosetting resin, an ultraviolet curing resin, or a curable sealant. That is, the thermosetting resin, the ultraviolet curing resin, or the curable sealant may be applied to the bellows structure or the mesh structure to ensure flexibility before curing while improving shape retention after curing.

[0041] As described above, the protective member 10 according to this embodiment is a protective member 10 that covers cables placed within a structure 50 buried underground. The protective member 10 covers the cables from the radially outer side of the cables for at least a predetermined distance along the longitudinal direction of the cables from a cable hole 53a, which is provided in a wall (side wall 53) of the structure 50 and through which the cables pass, toward the inside of the structure 50. The protective member 10 contains a conductive material and is flexible at least when the shape is determined, and is shape-retaining at least after the shape is determined. By adopting such a configuration, shape-retaining properties are imparted to some of the cables passing through the structure 50 buried underground, thereby enabling the cables to be spaced apart from one another. Furthermore, the protective member 10 contains a conductive material, which enables other cables in close proximity to be protected from unwanted electromagnetic waves.

[0042] In this embodiment, the protective member 10 is configured to have a bellows structure containing a conductive material. By adopting such a configuration, the bellows structure alone is flexible when the shape is determined and can retain its shape after the shape is determined, thereby simplifying the process from attachment to use of the protective member 10.

[0043] In this embodiment, the protective member 10 is formed as a mesh structure containing a conductive material. By adopting such a configuration, the mesh structure alone is flexible when the shape is determined and can retain its shape after the shape is determined, thereby simplifying the process from attachment to use of the protective member 10.

[0044] In this embodiment, the layer 10b containing a conductive material is formed on the base material 10a made of a thermosetting resin, an ultraviolet curing resin, or a curable sealant, or the base material 10a is configured to contain a conductive material. By adopting such a configuration, the shape retention of the protective member 10 after the shape is determined can be further improved.

[0045] In this embodiment, the protective member 10 is configured to be divided at least at one location in the circumferential direction. By adopting this configuration, the protective member 10 can be attached from the radially outer side in a connected state without first removing the power cable 20. This improves the workability when attaching the protective member 10.

[0046] Although the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art would easily be able to make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included within the scope of the present invention. For example, the functions included in each component, step, etc. can be rearranged so as not to cause logical inconsistencies, and multiple components, steps, etc. can be combined or divided into one.

[0047] For example, in the present embodiment, the protective member 10 is configured to be attached to a portion (a predetermined distance) of the power cable 20, but this is not limited to this embodiment. The protective member 10 may be provided, for example, to the entire area of ​​the power cable 20 located in the internal space S of the structure 50. The protective member 10 may also be provided to cables other than the power cable 20 (such as the communication cable 30). In this case, it is preferable to attach the protective member 10 to all of the communication cables 30 located in the internal space S of the structure 50.

[0048] In the present embodiment, the protective member 10 is configured to cover from the radially outer side at least a predetermined distance along the longitudinal direction of the cable from the cable holes 53 a, 54 a provided in the side walls 53, 54 through which the cable passes toward the inside of the structure 50, but is not limited to this configuration. The protective member 10 may also be configured to cover from the radially outer side at least a predetermined distance along the longitudinal direction of the cable from the cable holes in, for example, the top wall 51 or the bottom wall 52 other than the side walls 53, 54, 55, 56 toward the inside of the structure 50.

[0049] The following additional notes are provided regarding the above-described embodiments.

[0050] (Supplementary Item 1) A protective element for covering a portion of a cable placed in a structure buried underground, the protective element covering the cable from the radially outer side for at least a predetermined distance along the longitudinal direction of the cable from a cable hole provided in a wall of the structure through which the cable passes toward the inside of the structure, the protective element including a conductive material, and the protective element being flexible at least when the shape is determined and having shape-retaining properties at least after the shape is determined. (Supplementary Item 2) The protective element according to Supplementary Item 1, which is formed as a bellows structure including a conductive material. (Supplementary Item 3) The protective element according to Supplementary Item 1, which is formed as a mesh structure including a conductive material. (Supplementary Item 4) The protective element according to Supplementary Item 1, which has a layer including a conductive material formed on a substrate made of a thermosetting resin, an ultraviolet-curing resin, or a curable sealant, or the substrate includes a conductive material. (Supplementary Item 5) The protective element according to any one of Supplementary Items 1 to 4, which is divided at least at one location in the circumferential direction.

[0051] REFERENCE SIGNS LIST 10 Protective member 10a Base material 10b Layer 11 Flange portion 11a Fixing hole 15 Cable tie 16, 17 Fastening bolt 20 Power cable 21 Filter member 22 Fixing member 30 Communication cable 31 Filter member 32 Fixing member 50 Structure 51 Ceiling wall 52 Bottom wall 53, 54, 55, 56 Side wall 53a, 53b, 54a, 54b Cable hole 57 Neck portion 57a ​​Upper opening 61, 62, 63, 64 Duct S Inner space

Claims

1. A protective member that covers a cable placed inside a structure buried underground, the protective member covering the cable from the radially outer side thereof for at least a predetermined distance along the longitudinal direction of the cable from a cable hole that is provided in the wall of the structure and through which the cable passes toward the inside of the structure, the protective member including a conductive material, and having flexibility at least when the shape is determined, and having shape retention at least after the shape is determined.

2. The protective element of claim 1, formed as a bellows structure containing a conductive material.

3. The protective element according to claim 1, which is formed as a mesh structure containing a conductive material.

4. The protective member according to claim 1, wherein a layer containing a conductive material is formed on a substrate made of a thermosetting resin, an ultraviolet curing resin, or a curable sealant, or the substrate itself contains a conductive material.

5. A protective member according to any one of claims 1 to 4, which is divided at least at one location in the circumferential direction.

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