Heat-resistant structure

Abstract

A heat-resistant structure (1) that is to be provided in a conduit (P) that accommodates a power cable (C) comprises: a heat insulation part (11) that is provided along an inner wall of the conduit (P) and suppresses transmission of heat from the power cable (C) to the inner wall; and a heat dissipation part (12) that is provided to an outer surface of the power cable (C) and transmits heat into the air.

Description

Heat resistant structure

[0001] The present disclosure relates to heat-resistant structures.

[0002] As a method for utilizing existing stocks of communication equipment, efforts are being considered to reduce the cost of laying power cables by laying power cables in communication conduits where no communication cables are installed. Typically, when laying power cables, dedicated power conduits are used. Dedicated power conduits are made of materials that can withstand heat of, for example, 80°C or higher, and their physical properties do not deteriorate even when the power cables generate heat. For example, Non-Patent Document 1 discloses information on heat resistance as a wire standard for dedicated power conduits.

[0003] PVC Pipe and Fittings Association, "PVC Pipe and Fittings Association Standards for Electric Utility Tunnel Pipe Materials," p. 1, 2022

[0004] If the communication conduit is made of PVC pipe, the heat generated by the power cable may cause a deterioration in its physical properties or deformation. To make the conduit meet the heat resistance requirements, it is necessary to replace it with a dedicated power conduit, which requires excavation work and increases costs.

[0005] The present disclosure has been made in view of the above circumstances, and aims to suppress deterioration of conduits caused by heat generation in power cables.

[0006] A heat-resistant structure according to one embodiment is a heat-resistant structure provided in a conduit that accommodates a power cable, and includes a heat-shielding section that is provided along an inner wall of the conduit and that suppresses conduction of heat from the power cable to the inner wall, and a heat-dissipating section that is provided on an outer surface of the power cable and that conducts the heat into the air.

[0007] According to the present disclosure, deterioration of the conduit caused by heat generation in the power cable can be suppressed.

[0008] It is a figure which shows the pipeline and the manhole provided with the heat-resistant structure. It is a cross-sectional view of the heat-resistant structure. It is a figure for explaining the heat dissipation part in the room of the manhole. It is a figure for explaining the procedure of installing the heat-resistant structure.

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0010] In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0011] An overview of this embodiment will be described with reference to Fig. 1. The heat-resistant structure 1 according to this embodiment is provided in a conduit P that houses a power cable C, and includes a heat-shielding portion 11 that is provided along the inner wall of the conduit P and that suppresses heat conduction from the power cable C to the inner wall, and a heat-dissipating portion 12 that is provided on the outer surface of the power cable C and that conducts heat into the air.

[0012] In this embodiment, the conduit P is a conduit for a communication cable, and is made of a material that can withstand heat of less than 80°C. Specific examples of the conduit P include polyvinyl chloride pipes. However, the conduit P is not limited to this, and may be a steel pipe, a cast iron pipe, or the like. According to this embodiment, inside the conduit P, the heat dissipation section 12 removes heat generated from the power cable C, preventing the power cable C from becoming too hot. Furthermore, the heat shield 11 protects the conduit P from the heat generated by the power cable C. Therefore, deterioration of the conduit P due to heat generated by the power cable C can be suppressed.

[0013] The configuration of the heat-resistant structure 1 according to this embodiment will be described with reference to Fig. 2. The heat-resistant structure 1 includes a heat-shielding portion 11 and a heat-dissipating portion 12. Fig. 2 shows a cross section of the heat-resistant structure 1.

[0014] The heat shield 11 is a tubular body concentric with the pipeline P. The outer diameter of the heat shield 11 may be the same as the inner diameter of the pipeline P. That is, the radially outer surface of the heat shield 11 may be in contact with the inner wall surface, which is the radially inner surface of the pipeline P. The axial length of a single heat shield 11 may be the same as the pipeline P or may be shorter than the pipeline P. When the heat shield 11 has a length shorter than the pipeline P, multiple heat shields 11 may be provided inside the pipeline P in an axially continuous manner. The heat shield 11 reflects heat from the power cable C and suppresses heat conduction from the power cable C to the inner wall of the pipeline P. FIG. 2 shows an outer member 111 and an inner member 112 that constitute the heat shield 11. The outer member 111 may be made of a material with low emissivity and heat reflectivity, such as polished aluminum or copper. The inner member 112 may be made of a material with low thermal conductivity, such as polyester or glass wool.

[0015] The heat dissipation portion 12 is provided on the outer surface of the power cable C and conducts heat from the power cable C. The heat dissipation portion 12 includes, for example, a heat dissipation sheet or heat dissipation paint. The heat dissipation portion 12 may be made of a ceramic material such as silicon carbide or aluminum nitride, or an alloy material such as copper or molybdenum.

[0016] In this embodiment, the heat dissipation unit 12 is provided continuously along the wall surface W of the manhole M buried underground around the connection port of the conduit P of the manhole M. The heat dissipation unit 12 may be attached to the wall surface W with an adhesive or the like. Referring again to FIG. 1 , the heat dissipation unit 12 provided on the outer surface of the power cable C is provided continuously in the vertically upward direction along the wall surface W of the manhole M after exiting the conduit P inside the manhole M. FIG. 3 is a diagonal view of the connection port of the conduit P in FIG. 1 inside the manhole M. In FIG. 3 , the position of the connection port of the conduit P is indicated by an arrow. Referring to FIG. 3 , the heat dissipation unit 12 provided on the outer surface of the power cable C, indicated by a dashed line, enters the manhole M from the connection port of the conduit P and extends from the connection port position into the manhole M, extending as a plane along the wall surface W. The shape of the heat dissipation unit 12 when provided along the wall surface W is not limited to the rectangular shape shown in FIG. 3 and may be freely set. For example, the heat dissipation unit 12 may be provided continuously in the downward direction in addition to or instead of in the upward direction in the vertical direction. In Fig. 3, the power cable C coming out of the connection port is shown running straight inside the manhole M, but the power cable C and the heat dissipation unit 12 provided on the outer surface of the power cable C may be bent and installed along the floor or wall of the manhole M so as not to interfere with the movement of workers.

[0017] The heat dissipation section 12 may be provided continuously along at least one of the floor and ceiling surfaces of the manhole M, instead of or in addition to the wall surface W of the manhole M. The larger the area of ​​the heat dissipation section 12 that is in contact with the air, the more heat is conducted into the air and the easier it is to dissipate heat. By providing the heat dissipation section 12 extending from the conduit P in a plane within the manhole M, the heat from the power cable C can be efficiently dissipated.

[0018] Within the manhole M, the heat dissipation unit 12 may be partially detached from the power cable C. This reduces the cost of using the heat dissipation unit 12.

[0019] 4, a procedure for workers to install the heat-resistant structure 1 will be described. In the following, it is assumed that a pipe P is provided between two manholes including a manhole M, a first worker is in one of the two manholes, and a second worker is in the other manhole M.

[0020] In step S101, the heat shield 11 is installed inside the pipeline P. Specifically, first, a first worker inside one of the manholes uses a towing tool or the like to insert the heat shield 11 into the pipeline P from the connection port of the pipeline P. A second worker inside the other manhole M pulls out the towing tool or the like from the connection port of the pipeline P. This is not limiting, and multiple heat shields 11 may be installed by one of the first or second worker sequentially pushing multiple heat shields 11 into the pipeline P.

[0021] In step S102, the heat dissipation portion 12 is attached to the outer surface of the power cable C. The first worker wraps a heat dissipation sheet serving as the heat dissipation portion 12 around the power cable C, for example.

[0022] In step S103, the power cable C with the heat dissipation unit 12 attached is installed. Specifically, first, a first worker uses a pulling tool or the like to insert the power cable C with the heat dissipation unit 12 attached from the connection port of the conduit P into the inside of the heat shield 11 provided in the conduit P. A second worker pulls out the pulling tool or the like from the connection port of the conduit P, thereby installing the power cable C with the heat dissipation unit 12 attached inside the heat shield 11.

[0023] In step S104, the second worker attaches the heat dissipation portion 12 provided on the power cable C coming out of the connection port to the conduit P in a continuous, flat manner to a predetermined position on the wall surface W, floor, ceiling, or the like around the connection port to the conduit P inside the manhole M where the second worker is located. After that, the procedure for installing the heat-resistant structure 1 is completed.

[0024] The following additional notes are provided regarding the above-described embodiments.

[0025] (Supplementary Item 1) A heat-resistant structure provided in a conduit that accommodates a power cable, the heat-resistant structure comprising: a heat-shielding part provided along an inner wall of the conduit to suppress conduction of heat from the power cable to the inner wall; and a heat-dissipating part provided on an outer surface of the power cable to conduct the heat into the air. (Supplementary Item 2) The heat-resistant structure according to Supplementary Item 1, wherein the heat-shielding part is a tubular body concentric with the conduit. (Supplementary Item 3) The heat-resistant structure according to Supplementary Item 1 or 2, wherein the conduit is connected to a manhole buried underground, and the heat-dissipating part is provided continuously along the wall surface of the manhole around a connection port of the manhole to the conduit. (Supplementary Item 4) The heat-resistant structure according to Supplementary Item 3, wherein the heat-dissipating part is provided continuously along at least one of a floor surface and a ceiling surface of the manhole.

[0026] The present disclosure is not limited to the above-described embodiments, and the configurations shown in the drawings can be modified without departing from the spirit of the present disclosure.

[0027] 1 heat-resistant structure 11 heat-shielding part 111 outer member 112 inner member 12 heat-dissipating part

Claims

1. A heat-resistant structure provided in a conduit that houses a power cable, comprising: a heat-shielding section provided along the inner wall of the conduit to suppress the conduction of heat from the power cable to the inner wall; and a heat-dissipating section provided on the outer surface of the power cable to conduct the heat into the air.

2. A heat-resistant structure according to claim 1, wherein the heat-shielding portion is a tubular body concentric with the pipeline.

3. A heat-resistant structure according to claim 1 or 2, wherein the conduit is connected to a manhole buried underground, and the heat dissipation section is provided continuously along the wall surface of the manhole around the connection port of the manhole to the conduit.

4. A heat-resistant structure according to claim 3, wherein the heat dissipation section is provided continuously along at least one of the floor and ceiling surfaces of the manhole.

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