Connection cutting device and connection removal method

Abstract

To provide a connection cutting device and a connection removal method that can efficiently cut the connection of a POF cable used as a three-phase cable, thereby shortening a work time and thereby improving work efficiency.SOLUTION: A connection cutting device according to the present invention is a connection cutting device (cutting device 200) that cuts in a manhole 30 a connection 110 that connects three-phase cables 100 together inside the manhole 30, and includes a wire saw 210 that is routed around the connection 110 and cuts the connection 110, a main pulley 220 that is installed along the wall 36 or floor 34 of the manhole and rotates the wire saw 210, a plurality of guide pulleys 230 that guide the wire saw 210 from the main pulley 220 to the cutting position, and a drive device 240 that rotates the main pulley 220.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a connection cutting device that cuts a connection that connects three-phase cables together inside a manhole, and a connection removal method using the same. [Background technology]

[0002] In recent years, underground cabling has become increasingly common in cities due to considerations of aesthetics and safety. In underground cabling, troughs and conduits are buried underground, and power cables, communication cables, etc. (hereinafter referred to as underground cables) are laid inside them. Underground cables are removed when they deteriorate over time or are no longer needed.

[0003] As a method for removing an underground cable, for example, Patent Document 1 discloses a "method for removing an underground ultra-high voltage power transmission cable that has been laid for a long time in an underground conduit connecting two manholes." The underground ultra-high voltage power transmission cable removal method in Patent Document 1 includes "a step of providing a temporary hook in the earthen floor of a manhole that has the terminal end of one of the two ends of the power transmission cable that needs to be removed, both ends of which have been cut in advance, a step of connecting a hydraulic jack to the temporary hook, a step of connecting the terminal end of the power transmission cable to the hydraulic jack, and a step of driving the hydraulic jack and using its pulling force to pull the power transmission cable from the conduit into the manhole against lateral pressure and its own weight pressure." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7177537 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, when an underground cable is removed from a manhole, both ends of the power transmission cable are cut in advance to form terminations that are connected to hydraulic jacks. In contrast, when the power transmission system is a three-phase, three-wire system, a three-phase cable is used, with three underground cables forming one circuit. A well-known three-phase cable is a POF (Pipe Oiled Filled) cable, in which three (three-phase) cable cores are arranged inside a steel pipe, and the steel pipe is filled with insulating oil, an insulating material, to cover the cable cores.

[0006] POF cables (three-phase cables) have steel pipes welded to their joints. In other words, three-phase cables in multiple conduits are connected via joints by welding each steel pipe to a joint inside a manhole. Therefore, when removing a POF cable from a manhole, the joints are first cut and disassembled, and then the disassembled joints are removed from inside the manhole.

[0007] When cutting and dismantling a POF cable connection, it is first necessary to remove the weld between the steel pipe of the POF cable and the connection by gouging or other methods. For this reason, dismantling a POF cable connection requires more time and effort than dismantling the connection of other cables. Therefore, there was a need to improve work efficiency. In addition, because the connection of a POF cable is larger than the connection of other cables, there are more cutting points, which also contributes to the longer work time.

[0008] In view of these problems, the present invention aims to provide a connection cutting device and a connection removal method that can efficiently cut the connection of a POF cable used as a three-phase cable, thereby shortening the work time and thereby improving work efficiency. [Means for solving the problem]

[0009] In order to solve the above problems, a typical configuration of the connection cutting device of the present invention is a connection cutting device that cuts a connection that connects three-phase cables together inside a manhole, and is characterized by comprising a wire saw that is routed around the connection and cuts the connection, a main pulley that is installed along the wall or floor of the manhole and rotates the wire saw, a plurality of guide pulleys that guide the wire saw from the main pulley to the cutting position, and a drive device that rotates the main pulley.

[0010] The wire saw may be run over the connection portion so as to cut it from above to below.

[0011] In order to solve the above problems, a typical configuration of the connection removal method of the present invention is a connection removal method in which the connection is cut inside a manhole using the above-mentioned connection cutting device and removed outside the manhole, characterized in that the connection is cut multiple times starting from the side closest to the manhole's discharge outlet, and the cut connection is sequentially transported outside the manhole. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a connection cutting device and a connection removal method that can efficiently cut the connection of a POF cable used as a three-phase cable, thereby shortening the work time and thereby improving work efficiency. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating a work site where a three-phase cable is removed. [Figure 2] FIG. 1 is a diagram illustrating a three-phase cable. [Figure 3] 10A and 10B are diagrams illustrating an example in which an upper connection portion is cut by a cutting device installed on a wall surface. [Figure 4] FIG. 4 is an enlarged view of a main part of FIG. 3. [Figure 5] 10 is an enlarged view of a main part when a lower connecting portion is cut by a cutting device installed on a wall surface. FIG. [Figure 6] 10 is a diagram illustrating an example in which an upper connection portion is cut by a cutting device installed on the floor surface. FIG. [Figure 7] FIG. 7 is an enlarged view of a main part of FIG. 6. [Figure 8] 10 is an enlarged view of a main part when a lower connecting portion is cut by a cutting device installed on the floor surface. FIG. [Figure 9] FIG. 10 is a diagram illustrating an example in which a cooling device is applied. [Figure 10] FIG. 10 is an enlarged view of the area around the water spray nozzle that cools the cutting position. [Figure 11] FIG. 1 is an enlarged view of the area around a water sprinkler pulley that cools the wire saw. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0015] Fig. 1 is a diagram illustrating a work site 10 where a three-phase cable 100 is to be removed. As shown in Fig. 1, at the work site, conduits 20 are buried under a road surface 12, and manholes 30 for maintenance work are provided at predetermined intervals between the conduits 20.

[0016] 2A and 2B are diagrams illustrating a three-phase cable 100, with Fig. 2A being a cross-sectional view and Fig. 2B being a perspective view of the three-phase cable 100 (three underground cables 102). As shown in Figs. 1 and 2, the three-phase cable 100 (POF cable) is laid inside a conduit 20, which is a steel pipe, and the conduit 20 is filled with insulating oil (not shown) and pressurized.

[0017] As shown in Fig. 2(a), a three-phase cable 100 is made up of three underground cables 102a, 102b, and 102c. As shown in Fig. 2(b), the three underground cables 102a, 102b, and 102c have conductors 106 (segmented conductors) covered on their outer peripheries with sheaths 108, and skid wires 104 wound around the outer peripheries of the sheaths 108. In the following description, the three underground cables 102a, 102b, and 102c will be referred to as underground cables 102 unless otherwise distinguished.

[0018] When removing the three-phase cable 100 (POF cable), first, the connection parts 110 that connect the three-phase cable 100 to the multiple conduits 20 connected to the manhole 30 are cut and disassembled. In the example shown in Fig. 1, two connection parts 110 (upper connection part 110a and lower connection part 110b) are arranged above and below inside the manhole 30.

[0019] The upper connection part 110a is hung from the ceiling 32 of the manhole 30 by a hook 40. The lower connection part 110b is fixed to the floor surface 34 of the manhole 30 by a fastener 42. In the following description, when there is no need to distinguish between the upper connection part 110a and the lower connection part 110b, they will simply be referred to as connection part 110.

[0020] In this embodiment, a configuration in which two connection parts 110 are arranged one above the other inside the manhole 30 is illustrated, but the present invention is not limited to this. The connection part cutting device and the connection part removal method using the same of this embodiment can be applied even when there is one connection part 110 or when there are three or more connection parts 110.

[0021] (Connection disconnection device) 3 to 5 are diagrams illustrating a connection section cutting device (hereinafter, cutting device 200) according to this embodiment. FIG. 3(a) is a diagram illustrating an example in which an upper connection section 110a is cut by a cutting device 200 installed along a wall surface 36, and FIG. 3(b) is a diagram showing the connection section 110 in a see-through manner. FIG. 4 is an enlarged view of a main part of FIG. 3(b). FIG. 5 is an enlarged view of a main part in which a lower connection section 110b is cut by a cutting device 200 installed on a wall surface 36. For ease of understanding, the connection section 110 is shown by a dashed line in FIGS. 3 to 5.

[0022] In this embodiment, the connection portion 110 arranged inside the manhole 30 is cut inside the manhole 30 using a cutting device 200 shown in Figures 3 and 4. As shown in Figures 3 and 4, the cutting device 200 of the first embodiment includes a wire saw 210, a main pulley 220, a plurality of guide pulleys 230, and a drive device 240.

[0023] The wire saw 210 is a cutter made of a circular wire with diamond beads fixed in a rosary shape. The wire saw 210 is wound around the connection part 110 and rotates in conjunction with the main pulley 220 to cut the connection part 110. The wire saw 210 is wound around the upper connection part 110a in FIGS. 3 and 4, and around the lower connection part 110b in FIG. 5.

[0024] Three mounts (mounts 250a, 250b, 250c) are installed along the wall surface 36 (see FIG. 1) inside the manhole 30. Of the three mounts, mount 250a is fixed to the wall surface 36 (see FIG. 1) of the manhole 30 by a bracket 251, and mounts 250b and 250c are fixed (standing) to the floor surface 34 of the manhole 30. In the following description, mounts 250a, 250b, and 250c will be simply referred to as mount 250 unless they are to be particularly distinguished from one another.

[0025] The main pulley 220 and the plurality of guide pulleys 230 are each supported by a frame 250. The main pulley 220 is supported by a frame 250a and is installed along the wall surface 36 of the manhole 30. When the main pulley 220 is rotationally driven by the driving device 240, the wire saw 210 rotates in conjunction with the main pulley 220.

[0026] The plurality of guide pulleys 230 guide the wire saw 210 from the main pulley 220 to the cutting position of the joint 110. The number and arrangement of the guide pulleys 230 can be set appropriately according to the situation at the site.

[0027] 3 and 4, the cutting device 200 of this embodiment is provided with a tension mechanism 260 that applies tension to the wire saw 210. The tension mechanism 260 includes a rack 262 (spur gear) fixed to the stand 250a, and a feeder device 264 that meshes with the rack 262 to move the drive device 240.

[0028] (Connection removal method) Next, a connection part removal method using the cutting device 200 according to this embodiment will be described. In the connection part removal method according to this embodiment (hereinafter simply referred to as the removal method), the cutting device 200 is used inside the manhole 30 to cut the connection part 110 multiple times, starting from the side closer to the discharge opening 38 of the manhole 30. The cut connection parts 110 are then sequentially carried out of the manhole 30 and removed.

[0029] The procedure for removing the connecting portion 110 is to disassemble and remove the upper connecting portion 110a, and then disassemble and remove the lower connecting portion 110b.

[0030] In this embodiment, the wire saw 210 is moved so as to cut the connection portion 110 from above toward below. As described above, the upper connection portion 110a is suspended from the ceiling 32 of the manhole 30 by the hook 40. For this reason, when the wire saw 210 is moved so as to cut the upper connection portion 110a from below toward above, the upper connection portion 110a is urged upward by the wire saw 210 and becomes lifted. This makes it difficult for the force of the wire saw 210 to be applied to the upper connection portion 110a, reducing cutting efficiency.

[0031] In contrast, if the wire saw 210 is moved around so as to cut from above to below the upper joint portion 110a, a downward force is applied from the wire saw 210 to the upper joint portion 110a. In other words, the wire saw 210 can be moved across the upper joint portion 110a (steel pipe) so as to gather up and cut the free three-phase cables 100. This improves cutting efficiency.

[0032] Furthermore, when cutting the lower connecting portion 110b, the upper connecting portion 110a has already been removed. Therefore, rather than moving the wire saw 210 from below upward through the narrow space between the floor surface 34, it is more efficient to move the wire saw 210 from above downward after removing the upper connecting portion 110a, where sufficient space is secured.

[0033] When dismantling the upper connection part 110a, first, a pipe cutter (not shown) is used to cut a cutting position P1 (see FIG. 1) near the boundary between the upper connection part 110a and the pipe 20 exposed inside the manhole 30. Then, the insulating oil filled inside the pipe 20 is drained at the cutting position P1. The three-phase cable 100 is also cut at this position to ensure the cable length protruding from the pipe opening.

[0034] Next, the connecting portion 110 is cut at cutting position P2 using cutting device 200. Cutting position P2 is the distance from cutting position P1, that is, the position at which the width W of the connecting portion 110 (hereinafter referred to as the cut piece) after cutting at cutting positions P1 and P2 becomes "capable of being carried out through the discharge opening 38 of the manhole 30."

[0035] After the wire saw 210 is wound around the upper joint portion 110a, the drive device 240 is driven to rotate the main pulley 220. Then, the wire saw 210 rotates in conjunction with the main pulley 220, and is guided to the upper joint portion 110a by the multiple guide pulleys 230, and the upper joint portion 110a is cut at the cutting position P2.

[0036] At this time, the wire saw 210 moves downward as the upper connection portion 110a is cut from above downward, causing slack in the wire saw 210. Therefore, in parallel with the cutting by the wire saw 210, the above-mentioned tension mechanism 260 (see FIG. 4) is operated.

[0037] In the tension mechanism 260, the feeder device 264 moves on the rack 262 in a direction away from the cutting position P2. As a result, the drive device 240 fixed to the feeder device 264, and therefore the main pulley 220, also move in a direction away from the cutting position P2. As a result, the wire saw 210 hanging on the main pulley 220 is pulled in a direction away from the cutting position P2, and tension is applied. Therefore, slack in the wire saw 210 at the cutting position P2 can be suitably prevented.

[0038] After the connection portion is cut at cutting position P2 as described above, the three-phase cable 100 inside the conduit 20 is cut at cutting location P1. This allows the cut pieces between cutting positions P1 and P2 to be moved inside the manhole 30. Next, the pipe opening 20a of the conduit 20 is cut at cutting position P3 near the wall. Once this has secured space in which the cut pieces can be removed, the cut pieces P1-P2 and the pipe opening 20a are sequentially removed from the removal opening 38 and removed from the manhole 30.

[0039] If the cut pieces P1-P2 can be removed by simply cutting the pipe opening 20a, the pipe opening 20a is removed after the cut pieces P1-P2. If the cut pieces P1-P2 cannot be removed even after cutting the pipe opening 20a of the pipeline 20, the pipe opening 20a is removed first.

[0040] After the "cut pieces P1-P2" closest to the discharge opening 38 are carried out, the upper connecting portion 110a is cut approximately every width W (cutting positions P4, P5, P6, P7), and each cut piece is carried out sequentially in the same manner as described above. As a result, the upper connecting portion 110a is removed from inside the manhole 30.

[0041] After the upper connecting portion 110a has been removed from inside the manhole, the lower connecting portion 110b is removed. In this case, the wire saw 210 is moved around to cut the lower connecting portion 110b from above downward, as shown in Fig. 5. Then, in the same manner as when the upper connecting portion 110a was removed, the lower connecting portion 110b is cut multiple times, starting from the side closest to the discharge port 38, and the cut pieces are carried out through the discharge port 38.

[0042] As described above, according to the cutting device 200 of this embodiment and the cutting method using the same, the connection part 110 can be cut and dismantled by shifting the position at which the wire saw 210 is routed relative to the connection part 110. Therefore, the connection part 110 can be efficiently cut and dismantled in a narrow space such as a manhole 30, which makes it possible to shorten the work time and thereby improve work efficiency.

[0043] In particular, when the three-phase underground cables 102 are stacked in bales inside the connection section, as in the case of the three-phase cable 100 described above, resulting in few longitudinal fixing points, it is extremely common that there is no space inside the manhole to set up a conventional disc cutter. Even if there is space, when using a conventional disc cutter, the object to be cut will slip away (bend), causing the cutter to tighten and become immobile. For this reason, conventional disc cutters cannot cut underground cables 102 stacked in bales. In contrast, with the cutting device 200 of this embodiment, the wire saw 210 is not tightened, making it possible to cut underground cables 102 stacked in bales, as described above.

[0044] Additionally, a skid wire is wound spirally around each phase of the three-phase underground cable 102. Because the skid wire has no fixed point, the skid wire 104 cannot be cut by a conventional disc cutter because it escapes. Furthermore, with a conventional disc cutter, chips from the insulating paper of the underground cable create resistance, preventing the cutter from rotating. In contrast, with the cutting device 200 of this embodiment, the wire saw 210 is hung on the underground cable 102, so the skid wire 104 can be cut without escaping.

[0045] Furthermore, the three-phase cable 100 is in a so-called oil-impregnated state, meaning that it is impossible to remove all of the insulating oil that has been filled in it. In such cases, cutting with a disk cutter would generate a large number of sparks and therefore would be unsuitable. In contrast, the cutting device 200 of this embodiment cuts the cable by scraping it with the wire saw 210, making it possible to cut without generating sparks.

[0046] (Other uses of the cutting device) 6 to 8 are diagrams illustrating other usage modes of the cutting device 200 according to this embodiment. FIG. 6 is a diagram illustrating an example in which the upper connection portion 110a is cut by the cutting device 200 installed along the floor surface 34. FIG. 7 is an enlarged view of the main part of FIG. 6. FIG. 8 is an enlarged view of the main part in which the lower connection portion 110b is cut by the cutting device 200 installed on the floor surface 34. For ease of understanding, the connection portion 110 is shown by a dashed line in FIGS. 6 to 8.

[0047] 6, a base 250a is disposed along the floor surface 34, and the main pulley 220 is supported by the base 250a. That is, in FIGS. 6-8, the main pulley 220 and the drive unit 240 that rotates and drives it are disposed along the floor surface 34. Furthermore, since the base 250a is disposed along the floor surface 34, the tension mechanism 260 is also disposed along the floor surface 34.

[0048] Even when the cutting device 200 is installed on the floor surface 34, when cutting the upper connection portion 110a, the wire saw 210 is moved around to cut the upper connection portion 110a from above to below, as shown in Figures 6 and 7. Then, by cutting the upper connection portion 110a at multiple cutting locations, as in the case when the cutting device 200 is installed on the wall surface 36 (Figures 3 and 4), the upper connection portion 110a can be carried out through the carry-out opening 38 and removed.

[0049] Furthermore, when cutting lower connecting portion 110b, wire saw 210 is moved around to cut lower connecting portion 110b from above toward below, as shown in Fig. 8. Then, by cutting lower connecting portion 110b at multiple locations in the same manner as when cutting upper connecting portion 110a, lower connecting portion 110b can be carried out through outlet 38 and removed.

[0050] (cooling device) 9 to 11 are diagrams illustrating an example in which a cooling device is applied to the cutting device 200 according to this embodiment. The cutting device 200 shown in Fig. 9 is similar to that described using Figs. 6 and 7, and therefore, the same reference numerals are used for the overlapping parts, and the description thereof will be omitted.

[0051] Furthermore, in the example shown in Figure 9, sprinkler nozzle 320 is installed above the cutting position by wire saw 210 (see Figure 10; the support structure for sprinkler nozzle 320 is not shown). In addition, sprinkler pulley 330 is connected to guide pulley 230, which is located downstream from the cutting position (see Figure 11). Portable cooling water pump 310 is connected to sprinkler nozzle 320 and sprinkler pulley 330 to supply cooling water. Water supply hose 312 drawn from cooling water pump 310 branches into hose 314 connected to sprinkler nozzle 320 and hose 316 connected to sprinkler pulley 330.

[0052] 10 is an enlarged view of the area around spray nozzle 320, which cools the cutting position. Sprinkler nozzle 320 has the end of a tube bent to fit around the outer periphery of connecting part 110a, sealed with cap 322. Sprinkler nozzle 320 has multiple outlets 320a arranged on its underside, and sprays cooling water toward wire saw 210 (toward the cutting position) during cutting.

[0053] This configuration allows the wire saw 210 to be cooled during cutting. Furthermore, as the cutting progresses and the wire saw 210 enters the connection portion 110a, cooling water enters the inside of the connection portion 110 through the cut, thereby preventing the insulating oil from igniting.

[0054] It is preferable that watering nozzle 320 be flexible so that its curvature can be changed to accommodate connecting parts 110 of different diameters. Examples of flexible tubing that can be used include bellows tubing and plastic tubing. However, watering nozzle 320 may also be a rigid tubing bent into a roughly circular arc, a tubing bent at multiple angles, or a tubing structure consisting of multiple nozzles connected by piping. When using a nozzle, it is preferable to use a universal joint that allows the angle of the nozzle to be changed.

[0055] 11 is an enlarged view of the area around sprinkler pulley 330, which cools the wire saw. Sprinkler pulley 330 is a pulley with approximately the same diameter as the existing guide pulley 230. Sprinkler pulley 330 has a groove with outlet 330a, from which cooling water supplied from hose 316 is sprayed.

[0056] The water sprinkler pulley 330 is attached so as to overlap the guide pulley 230, and rotates freely together with the guide pulley 230 (it rotates following the wire saw 210). In the area where the water sprinkler pulley 330 is attached, the wire saw 210 is hung on the water sprinkler pulley 330 instead of the guide pulley 230.

[0057] With this configuration, the wire saw 210 heated by cutting can be cooled by being brought into contact with the cooling water reliably, thereby reducing wear on the wire saw 210 and extending its lifespan.

[0058] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0059] The present invention can be used in a connection cutting device that cuts a connection that connects three-phase cables together inside a manhole, and a connection removal method using the same. [Explanation of symbols]

[0060] 10...work site, 12...road surface, 20...pipe, 20a...pipe entrance, 30...manhole, 32...ceiling, 34...floor, 36...wall, 38...exit, 40...hook, 42...fixing device, 100...three-phase cable, 102...underground cable, 102a...underground cable, 102b...underground cable, 102c...underground cable, 104...skid wire, 106...conductor, 108...coating, 110...connection part, 110a...upper connection part, 110b...lower connection part, 200...cutting device, 210...wire saw, 220...main pulley, 230...guide pulley, 240...drive device, 250a...mounting stand, 250b...mounting stand, 250c...mounting stand, 251...bracket, 260...tension mechanism, 262...rack, 264...feeder device

Claims

1. A connection cutting device that cuts a connection that connects three-phase cables together inside a manhole, a wire saw that is run around the connection portion and cuts the connection portion; a main pulley installed along the wall or floor of the manhole to rotate the wire saw; a plurality of guide pulleys for guiding the wire saw from the main pulley to a cutting position; a drive unit that drives the main pulley to rotate; A connection cutting device comprising:

2. 2. The connection cutting device according to claim 1, wherein the wire saw is wound around the connection so as to cut it from above to below.

3. A connection removal method for cutting the connection within a manhole using the connection cutting device according to claim 1 and removing the connection to the outside of the manhole, comprising: The connecting portion is cut a plurality of times from the side closer to the discharge exit of the manhole, A method for removing a connection portion, characterized in that the cut connection portions are sequentially carried out of the manhole.

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