JP7340641B2 - Cable restraint method and double hose - Google Patents

Description

The present invention relates to a cable restraining method for restraining a cable laid in a conduit using a double hose, and a double hose.

A pipe line is installed between two manholes over a long distance, for example, several hundred meters. Also, cables such as underground power transmission cables are laid inside the conduit. If such a conduit is buried directly under a roadway, vibrations of the conduit caused by vehicles traveling on the road may cause the so-called wave-riding phenomenon in which the cables laid within the conduit move.

When the cable moves due to this wave-riding phenomenon, tension is generated in the cable, which affects equipment such as cable joints installed in the space inside the manhole, so countermeasures against the wave-riding phenomenon are required.

As a countermeasure to this problem, it is possible to fix the end of the cable with a cleat (metal fitting). For example, Patent Document 1 discloses a cable restraining device that restrains a plurality of cables laid in a conduit using three gripping hardware.

This cable restraint device includes a first gripping hardware, a second gripping hardware, and a third gripping hardware. The first gripping hardware is disposed between the cables near the conduit opening so as to bisect the plurality of cables laid in the conduit. The second gripping hardware fixes one of the cable groups separated by the first gripping hardware to the first gripping hardware. The third gripping hardware fixes the other cable group separated by the first gripping hardware to the first gripping hardware.

That is, in this cable restraint device, one cable group out of a plurality of cables is held by the first gripping hardware and the second gripping hardware, and the other cable group is held by the first gripping hardware and the third gripping hardware. grasp. For this reason, Patent Document 1 states that it is possible to obtain a high restraining force on the cable and to downsize the device.

Japanese Patent Application Publication No. 2008-125148

However, the cable restraint device of Patent Document 1 requires space for installing three gripping hardware, that is, cleats, in the manhole. For this reason, this cable restraint device cannot be applied to narrow existing manholes where space for installing cleats cannot be secured, and it is not possible to take measures against the cable wave-riding phenomenon. Further, even in a new manhole that will be constructed in the future, it is not always possible to secure sufficient space due to surrounding buried equipment such as gas pipes and water pipes, and it is preferable that the required space be small.

In view of these problems, the present invention provides a cable restraint method and second method that can be applied to narrow manholes where sufficient space for restraining cables cannot be secured, and that can obtain sufficient restraint force for cables. The purpose is to provide heavy hoses.

In order to solve the above problems, a typical configuration of the cable restraint method according to the present invention uses a double hose in which the front end of the inner hose is connected to the rear end of the outer hose, and the front end of the outer hose is connected to the hose reversing device. Pressurized fluid is introduced into the outer hose using a hose reversing device to advance the outer hose while inverting between the conduit and the cable, and between the front end of the outer hose and the hose reversing device. disconnect the cable from the injection port, open the front end of the outer hose, expose the rear end of the inner hose, and inject filling material from the rear end of the inner hose to expand and restrain the cable. It is characterized by

In the above configuration, by using a reversing method using a hose reversing device and a double hose, pressure fluid is first introduced into the outer hose of the double hose, and the outer hose is reversed between the conduit and the cable as the work progresses. let For this reason, the inner hose connected to the rear end of the outer hose can be inserted deeper into the pipe than in the case where a balloon such as a pressurized rubber bag to which internal pressure is applied is pushed into the pipe. In other words, with the above configuration, it is possible to insert a long inner hose between the conduit and the cable, which is unimaginable in the past.

Next, in the above configuration, the front end of the outer hose is opened, and the filling material is injected and pressurized from the rear end of the inner hose, which is long inserted between the conduit and the cable, to expand the inner hose and connect the cable. It can be applied to narrow manholes as it can provide sufficient restraint force to the cables without having to secure space for installing cleats etc. to restrain the cables inside the manhole. In addition, it is possible to reduce the manhole space and reduce costs.

Either or both of the outer hose and the inner hose are pressure-resistant hoses provided with fibers and resin, and when the inner hose is inflated with the outer hose inverted, the fiber layer is placed on the outside. It's good to have one.

As a result, the outer hose after inversion has a fiber layer disposed on the outside and a resin layer disposed on the inside. A fibrous layer is also arranged on the outside of the expanded inner hose. Here, the fiber layer is a surface having unevenness. Further, the resin layer is a softer surface than the fiber layer.

First, if you look at the outside hose after inversion, for example, the unevenness of the twist of a power cable made of three three-phase AC cables twisted in a spiral pattern, and the unevenness of the fiber layer placed on the outside of the outside hose after inversion. The frictional resistance can be significantly increased. Next, from the perspective of the expanded inner hose, the unevenness of the fiber layer placed on the outside of the expanded inner hose bites into the soft resin layer placed inside the outer hose after it is turned over, resulting in a significant increase in frictional resistance. can be increased significantly. Therefore, according to the above configuration, it is possible to reliably obtain a sufficient restraint force on the cable.

The filling material injected into the inner hose is preferably silicone oil containing carbon filler. Thereby, high heat dissipation performance and internal pressure maintenance performance can be obtained.

In order to solve the above problems, a typical configuration of the double hose according to the present invention is a double hose in which the front end of the inner hose is connected to the rear end of the outer hose. The inner hose is able to expand when it overlaps with the outer hose after inversion, and an anti-slip layer or high friction layer is placed on the inside of the outer hose before inversion and on the outside of the inner hose. A resin layer is disposed on the outside of the outer hose and on the inside of the inner hose.

In the double hose configured as described above, the inverted outer hose and the expanded inner hose overlap. Therefore, by using the reversing method using this double hose and reversing device, when the outer hose is reversed and advanced between the conduit and the cable, the inner hose can expand, and the inverted outer hose and the expanded inner hose When the conduit and cable are overlapped, it expands between the conduit and the cable, and the cable can be restrained.

In addition, with double hoses, if the inverted outer hose overlaps with the inflated inner hose and expands between the conduit and the cable, the cable may have an anti-slip layer or a high Since the friction layers are in contact with each other, it is possible to increase the frictional resistance, make it difficult to slip, and effectively restrain the cable. Furthermore, since the resin layer disposed inside the expanded inner hose has airtightness, it is possible to continue applying expansion pressure to the outer hose after being turned over.

The inner hose has a resin layer arranged on the inside and a fiber layer arranged on the outside, and at least at the rear end of the inner hose, the resin layer and the fiber layer are separate bodies, and the resin layer is linearly welded. It is preferable that a weld line is formed, and that the resin layer and the fiber layer are sewn together at the weld line. This makes it difficult for the welded wire to cleave or peel off even when the inner resin layer expands due to internal pressure, so it is possible to exert the cable restraining force due to high voltage.

An opening tube into which the filling material injection member is inserted is formed approximately in the center of the opening on the rear end of the inner hose, and the weld lines on both sides of the opening tube are inclined diagonally toward the opening tube. is preferred. As a result, compared to a case where the weld line is a straight line orthogonal to the axis of the inner hose, stress concentration on the weld line can be dispersed and peeling can be prevented.

According to the present invention, there is provided a cable restraining method and a double hose that can be applied to narrow manholes where sufficient space for restraining cables cannot be secured and can obtain sufficient restraining force for cables. be able to.

It is a figure showing the pipe line to which the cable restraint method in an embodiment of the present invention is applied. It is a figure explaining the reversal construction method which applies the cable restraint method in embodiment of this invention to a conduit. 3 is a diagram illustrating a double hose used in the cable restraint method of FIG. 2. FIG. It is a figure explaining the reversal construction method subsequent to FIG. 2. It is a figure explaining the state where the cable in a conduit is restrained by the double hose. It is a figure explaining the test which confirms the restraint force with respect to a cable. It is a figure explaining a filling material. It is a figure explaining other examples of a double hose. It is a figure explaining the structure of the end part of an inner hose. It is a figure explaining the structure of an inner hose.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely illustrative to facilitate understanding of the invention, and do not limit the invention unless otherwise specified. In this specification and the drawings, elements with substantially the same functions and configurations are given the same reference numerals to omit redundant explanation, and elements not directly related to the present invention are omitted from illustration. do.

FIG. 1 is a diagram showing a conduit 100 to which a cable restraint method according to an embodiment of the present invention is applied. The conduit 100 is installed over a long distance of several hundred meters, for example, between a manhole 102 and another manhole (not shown). A cable 104 such as an underground power transmission cable is laid inside the conduit 100.

If such a conduit 100 is buried directly under the roadway 106 as shown in the figure, the conduit 100 will vibrate when a vehicle such as a truck 108 runs on the road, causing the conduit 100 to be buried beneath the roadway 106. In some cases, the so-called wave riding phenomenon occurs in which the cable 104 moves. When the cable 104 moves due to this wave-riding phenomenon, tension is generated in the cable 104, and the cable joint portion 112 installed in the space 110 inside the manhole 102 may be displaced or damaged as shown in A in the figure.

Therefore, countermeasures against the wave riding phenomenon of the cable 104 are required. As a countermeasure to this problem, it is possible to restrain the cable 104 by installing a cleat (metal fitting) or the like for fixing the cable 104 in the space 110 of the manhole 102. However, even if the manhole 102 is a narrow existing one that does not have enough space to install a cleat, or if it is a new one that will be installed in the future, there are problems with surrounding buried equipment such as gas pipes and water pipes. It is not always possible to secure sufficient space.

Therefore, in this embodiment, as a countermeasure against the surfing phenomenon, a double hose is installed between the conduit 100 and the cable 104 by a reversing method using a hose reversing device 114 (see FIG. 2) and a double hose 116 (see FIG. 3). 116 was used to restrain the cable 104.

FIG. 2 is a diagram illustrating an inversion construction method in which the cable restraint method according to the embodiment of the present invention is applied to the conduit 100. FIG. 3 is a diagram illustrating the double hose 116 used in the cable restraint method of FIG. 2.

In the cable restraint method, a reversal method using a hose reversing device 114 and a double hose 116 is implemented. The hose reversing device 114 is mounted on the vehicle 118 shown in FIG. This is a device that allows you to

The hose reversing device 114 includes a pressure vessel 122 into which compressed air is introduced from an air introduction port 120 and an injection port 124. A reel 126 is rotatably provided inside the pressure vessel 122. A double hose 116 is wound around the reel 126 as shown in FIG. 2(b). The injection port 124 is a cylindrical portion provided at the tip of the pressure vessel 122.

As shown in FIG. 3, the double hose 116 has an outer hose 128 and an inner hose 130, and the front end 134 of the inner hose 130 is airtightly connected to the rear end 132 of the outer hose 128 by a connecting portion 136. The rear end 138 of the inner hose 130 is hermetically sealed, as is the front end 134 thereof. Further, the rear end 138 of the inner hose 130 is provided with an injection valve 140 for injecting a filling material such as compressed air. The valve 140 may be provided directly at the rear end 138 in this way, or a cylindrical body for filling the filling material may be attached to the rear end 138 and the valve 140 may be provided at the end of the cylindrical body.

The front end 142 of the outer hose 128 is airtightly connected to the injection port 124 of the hose reversing device 114, as shown in FIG. 2(b). As an example, the front end 142 of the outer hose 128 is placed on the inner periphery of the injection port 124 and is airtightly fixed by a fixture 144 or the like.

In the hose reversing device 114, compressed air is introduced into the pressure vessel 122 from the air introduction port 120 with the front end 142 of the outer hose 128 airtightly connected to the injection port 124 as shown in FIG. 2(b). Therefore, in the hose reversing device 114, the outer hose 128 receives pressure from the compressed air introduced into the pressure vessel 122, and the reel 126 further rotates in the direction shown by the arrow B, so that the reel 126 is rotated as shown in FIG. 2(c). Then, the outer hose 128 is sent out toward the injection port 124 and reversed at the injection port 124. Further, the outer hose 128 is injected out of the pressure vessel 122 from the injection port 124 while being reversed as shown in FIG. 2(d).

In this way, the hose reversing device 114 inverts the outer hose 128 of the double hose 116 and feeds the outer hose 128 out of the pressure vessel 122 as shown in FIG. into the space 110 through. Furthermore, the hose reversing device 114 inverts and advances the outer hose 128 through the space 110 of the manhole 102 between the conduit 100 and the cable 104.

Here, in the double hose 116 shown in FIG. 3, the outer hose 128 is in a state before being reversed, and the front end 134 of the inner hose 130 is connected to the rear end 132 of the outer hose 128 before being reversed. The outer hose 128 and the inner hose 130 are pressure-resistant hoses each having a resin layer formed by extrusion coating a fiber layer of aramid or the like with a resin such as soft polyvinyl chloride. The fibrous layer has a cylindrical shape made up of multiple warps and weft threads woven continuously in a spiral pattern around the warp threads so that the pressure hose can withstand the pressure of compressed air that acts when it is turned over or expanded as described below. Woven fabrics are preferred.

On the inside of the outer hose 128 before inversion shown in FIG. 3, that is, on the outside of the outer hose 128 after inversion, a fibrous layer 148 is arranged with hatching in the figure. The fibrous layer 148 is a surface having unevenness, and when the fibrous layer is a cylindrical woven fabric, it has an uneven surface due to the texture made of warp and weft yarns. On the other hand, a resin layer 150 is disposed on the outside of the outer hose 128 before being reversed, that is, on the inside of the outer hose 128 after being reversed. The resin layer 150 has a softer surface than the fiber layer 148. Further, on the outside of the inner hose 130, a fibrous layer 152 having a structure similar to that of the fibrous layer 148 and having unevenness shown by hatching in the figure is arranged.

FIG. 4 is a diagram illustrating the reversal construction method following FIG. 2. As shown in FIG. 4(a), when the outer hose 128 continues to be moved between the conduit 100 and the cable 104 while being reversed as shown by the arrow C (arrow D), the rear end 132 of the outer hose 128 The front end 134 of the inner hose 130 connected via the connection part 136 is sent out of the pressure vessel 122 from the injection port 124 and further advances between the conduit 100 and the cable 104.

Then, as shown in FIG. 4(b), the outer hose 128, which has continued to enter between the conduit 100 and the cable 104 as shown by the arrow D, is finally reversed over its entire length, and the inner hose 138 is moved as shown in the figure. A rear end 138 is sent out of the pressure vessel 122 from the injection port 124 and further reaches between the conduit 100 and the cable 104.

In this way, the inner hose 130 connected to the rear end 132 of the outer hose 128 can be inserted deeper into the conduit 100. In other words, the reversing method using the hose reversing device 114 and the double hose 116 allows for more efficient use than the conventional method of pushing and inserting a balloon, such as a pressurized rubber bag, into the conduit 100. A long inner hose 130 can be inserted between conduit 100 and cable 104.

At this time, the double hose 116 has an outer hose 128 that is inverted over its entire length between the conduit 100 and the cable 104 and a long inner hose 130 that is inserted between the conduit 100 and the cable 104 by the outer hose 128. The state will be as follows. In this state, in the double hose 116, the fiber layer 148 and the resin layer 150 are arranged on the outside of the inverted outer hose 128, respectively, and the fiber layer 152 is arranged on the outside of the inner hose 130.

Subsequently, as shown in FIG. 4C, the vicinity of the front end 142 of the outer hose 128, which is airtightly connected to the injection port 124 of the pressure vessel 122, is cut by, for example, a cutting device 154. In this manner, the front end 142 of the outer hose 128 is opened to expose the rear end 138 of the inner hose 130 and provide access to the valve 140 provided at the rear end 138, as shown in FIG. 4(c). Make it.

Then, as shown by arrow E in FIG. 4(d), compressed air as a filling material is injected from the rear end 138 of the inner hose 130 through the valve 140 at the rear end 138 of the inner hose 130, and thereby, Inflate the inner hose 130 as shown by arrow F. As a result, the double hose 116 is expanded between the conduit 100 and the cable 104 with the inverted outer hose 128 and the inflated inner hose 130 overlapping, and the cable 104 can be restrained.

Therefore, according to the cable restraining method of this embodiment, by using the double hose 116, the inner hose 130 is inserted long into the inner hose 130 between the conduit 100 and the cable 104, and the inner hose 130 is expanded. Since the cable 104 is restrained by the cable 104, a sufficient restraining force can be obtained for the cable 104 without having to secure a space for installing a cleat or the like to restrain the cable 104 inside the manhole 102, and it can be applied even to a narrow manhole 102. In addition, the space 110 of the manhole 102 can be reduced to reduce costs.

Further, in the double hose 116, the resin layer 150 placed on the outside of the outer hose 128 before being reversed becomes the inside of the outer hose 128 after being reversed. Therefore, the inside of the outer hose 128 after being inverted has an airtight structure in which resin is arranged. Therefore, in the double hose 116, the filling material does not leak, and it is possible to continuously invert the outer hose 128.

In addition, in the double hose 116, the fiber layer 148 disposed inside the outer hose 128 before inversion becomes the outer side of the outer hose 128 after inversion. Therefore, the uneven fiber layer 148 is arranged on the outside of the outer hose 128 after reversal, which increases the frictional resistance, so the cable 104 has excellent restraint force, and this allows the cable 104 to be stretched. The cable 104 can be effectively restrained by surface contact in the direction.

Further, the inside of the inner hose 130 has an airtight structure in which resin is arranged. Therefore, in the double hose 116, the fiber layer 152 disposed on the outside of the inner hose 130 expands as shown by arrow F in FIG. 4(d), and can continue to apply expansion pressure to the outer hose 128. Note that the filling material is not limited to the above-mentioned compressed air, but may also be water, or even a resin that expands and solidifies when it contains water.

FIG. 5 is a diagram illustrating a state in which the cable 104 in the conduit 100 is restrained by the double hose 116. Here, the cable 104 is a power cable in which three three-phase AC electric wires 156a, 156b, and 156c are twisted in a spiral shape, as shown in FIG. 5(a). In such a spirally wound cable 104, the size of the gap 158 with respect to the conduit 100 changes regularly depending on the position of the cable 104 according to the wavelength of the spiral. Note that FIGS. 5(b) and 5(c) show the GG cross section and the HH cross section of FIG. 5(a).

As an example, the cable 104 forms a gap 158a between the electric wires 156a, 156c and the conduit 100, into which the double hose 116 is inserted, in the GG cross section of FIG. 5(b). Further, the cable 104 forms a gap 158b between the electric wire 156a and the conduit 100, into which the double hose 116 is inserted, in the HH cross section of FIG. 5(c). As illustrated, the gaps 158a and 158b are different in size and shape.

In the gaps 158a and 158b, when viewed from the outer hose 128 after inversion, there are unevenness due to the twist caused by the electric wires 156a and 156c of the spirally twisted cable 104 (see FIG. 5(b)), and unevenness caused by the twist caused by the electric wire 156a (see FIG. 5(c)), the unevenness of the fiber layer 148 disposed on the outside of the inverted outer hose 128 bites in, so that the frictional resistance can be significantly increased. Moreover, when viewed from the expanded inner hose 130, the unevenness of the fiber layer 152 placed on the outside of the expanded inner hose 130 bites into the soft resin layer 150 placed inside the outer hose 128 after the inversion. Frictional resistance can be dramatically increased.

Therefore, the double hose 116 can reliably obtain sufficient restraint force on the cable 104 by expanding the inner hose 130 between the conduit 100 and the cable 104. Here, if changes in the size of the gaps 158a and 158b are regarded as peaks and valleys of the wavelength, there are three peaks and three valleys in one wavelength of the spiral. Therefore, by having the length of the double hose 116 that is ⅓ or more of the wavelength of the spiral, it is expected that both the peaks and valleys can be reliably suppressed and the cable 104 can be reliably restrained.

In the embodiment described above, both the outer hose 128 and the inner hose 130 are pressure-resistant hoses with a fiber layer coated with resin, and when the inner hose 130 is inflated with the outer hose 128 inverted, the fiber layer 148 is formed on the outside thereof. , 152, but the present invention is not limited to this, and only one of the outer hose 128 and the inner hose 130 may be a pressure-resistant hose, and the other may be made of a material in which a fiber layer made of a cylindrical woven fabric and a resin tube are stacked. In other words, the hose may have a fiber layer and a resin made of separate materials. Even in such a case, the double hose 116 can obtain sufficient restraint force on the cable 104 by expanding the inner hose 130.

Note that fiber layers 148 and 152 were arranged on the inside of the outer hose 128 and on the outside of the inner hose 130 before being reversed. However, the fiber layers 148 and 152 are merely examples of anti-slip layers or high-friction layers having a non-slip function, and any suitable anti-slip layer or high-friction layer may be used in place of the fiber layers 148 and 152.

Furthermore, a resin layer 150 was placed on the outside of the outside hose 128 and inside the inside hose 130 before being turned over. However, this resin layer 150 is merely an example of a coating layer having a function of providing airtightness, and any appropriate coating layer may be used in place of the resin layer 150.

The materials used for the above-mentioned anti-slip layer, high-friction layer and coating layer are preferably the optimal materials obtained through testing, but other materials can also be used as long as they satisfy the functions. Although tests have shown that an unprocessed fiber layer (a surface on which unevenness of the fibers appears) is most suitable for the anti-slip layer, it may be coated with latex to give it tackiness.

FIG. 6 is a diagram illustrating a test for confirming the binding force on the cable 104. In this test, as shown in FIG. 6(a), instead of the double hose 116 described above, an existing reversal hose 160, a tension gauge 162, and a lever block (registered trademark) 164 were prepared. The inversion hose 160 is a single-layer pressure-resistant hose that has a resin layer formed by extrusion coating a soft polyvinyl chloride resin on the outer surface of a cylindrical woven fabric. Then, a reversing hose 160 was inserted between the conduit 100 and the cable 104 in an inverted manner, one end 166 of the cable 104 and the tension gauge 162 were connected with a chain 168, and the tension gauge 162 and the lever block 164 were further connected with a chain 170. The inverted hose 160 inserted into the conduit 100 inverted has a fiber layer on the outside and a resin layer on the inside, and has the same configuration as the above-mentioned inverted outer hose 128.

In this test, by operating the lever block 164, a force (arrow I) that moves the cable 104 caused by the wave riding phenomenon is applied to the cable 104 as a tensile tension T, and the tensile tension T is measured with a tension meter 162. It was confirmed how much restraining force the reversing hose 160 had.

In the tests shown in FIGS. 6(b) and 6(c), reversing hoses 160 having diameters of 80 mm and 100 mm and lengths of 4 m, 8 m, and 12 m were prepared, respectively. In the graph in the figure, the horizontal axis is the internal pressure P of the reversing hose 160, and the vertical axis is the tensile tension T measured by the tension meter 162. The test was conducted with a target tensile tension of 6 (kN) and a tensile tension larger than the target of 10 (kN) for comparison. Furthermore, in the figure, "〇" and "x" indicate points where restraint was confirmed and points where restraint could not be confirmed, respectively.

According to the graph in FIG. 6(b), for the reversing hose 160 with a diameter of 80 mm, lengths of 8 m, and 12 m, the target tensile force is 6 (kN/m ² ) when the internal pressure P is in the range of 20-100 (kN/m 2 ). ) was confirmed. Furthermore, for the reversing hose 160 with a diameter of 80 mm and a length of 4 m, it was confirmed that the target tensile force was restrained at 6 (kN) when the internal pressure P was in the range of 40-100 (kN/m ² ). Furthermore, for the reversing hoses 160 with a diameter of 80 mm and lengths of 4 m, 8 m, and 12 m, it was confirmed that the tensile force was 10 (kN), which was larger than the target, and the internal pressure P was in the range of 40 to 100 (kN/m ² ). Ta.

According to the graph in FIG. 6(c), for the reversing hose 160 with a diameter of 100 mm and a length of 8 m, the tensile tension is 6 (kN) and 10 (kN) when the internal pressure P is in the range of 20 to 100 (kN/m ² ). ) was confirmed. Furthermore, in the case of the reversing hose 160 with a diameter of 100 mm and a length of 4 m, restraint with a tensile tension of 6 (kN) and 10 (kN) was confirmed within the range of internal pressure P of 40 to 100 (kN/m ² ). Furthermore, for the reversing hose 160 with a diameter of 100 mm and a length of 2 m, restraint with a tensile tension of 6 (kN) can be confirmed within the range of internal pressure P of 60-100 (kN/m ² ), and that the internal pressure P is 80- It was confirmed that the tensile force was 10 (kN) in a range of 100 (kN/m ² ).

Therefore, according to each graph, regardless of whether the diameter of the reversing hose 160 is 80 mm or 100 mm, if the length is 4 m or more, the internal pressure P can reach the target within the range of 40-100 (kN/m ² ). It was confirmed that it was possible to restrain the tensile tension of 6 (kN) and the tensile tension of 10 (kN) larger than the target. In other words, it has been found that if the initial internal pressure of the reversing hose 160 is 100 (kN/m ² ), sufficient restraining force can be obtained for the cable 104 even if the internal pressure decreases to 40 (kN/m ² ) over time. Ta.

In contrast, in the cable restraint method of this embodiment, a double hose 116 is used instead of the existing inverted hose 160, but the structure is the same in that fibers are placed on the outside and resin is placed on the inside. . Based on the above test results, a similar test was conducted using a double hose with a set outer hose length, and it was confirmed that a similar restraining force could be obtained for the cable 104.

FIG. 7 is a diagram illustrating the filling material injected into the inner hose 130. When the cable 104 is an underground power transmission cable, heat is generated due to high voltage and large current, but as the temperature rises, the impedance (electrical resistance) of the cable increases, so it is necessary to dissipate the heat. Here, if the double hose 116 that is in close contact with the cable 104 has low heat dissipation properties as in the present invention, heat will be trapped and the temperature will rise. Therefore, the filling material injected into the inner hose 130 needs to have high heat dissipation properties.

Further, in order for the double hose 116 to restrain the cable 104, it is necessary to apply internal pressure of a predetermined level or higher. Since the double hose 116 is intended to be installed for a long period of time ranging from several years to several decades, it is necessary to be able to maintain internal pressure (not depressurize) for a long period of time.

As shown in FIG. 7, the inventors conducted a comparative study on several filling materials. Water (Comparative Example 1) has high fluidity, so it has good filling properties, and can be disposed of on site, so it is easy to remove. It is particularly preferable in that it has good heat dissipation properties (thermal conductivity). However, since water becomes water vapor and depressurizes, its ability to maintain internal pressure over a long period of time is low, making it unsuitable as a filling material.

The product in which a super absorbent polymer is mixed with water (Comparative Example 2) has good airtightness in the short term because the super absorbent polymer becomes jelly-like when it absorbs water. However, the water still turns into steam and depressurizes. Furthermore, although Comparative Example 2 has good heat dissipation properties, it releases pressure, so it is not suitable as a filling material.

Air (Comparative Example 3) has excellent filling and removal properties, but has poor heat dissipation due to its low thermal conductivity. In addition, since it is a gas, it loses pressure, so its ability to maintain internal pressure over a long period of time is poor.

Since the urethane foam (Comparative Example 4) is solid, it has good sealing properties and can maintain high internal pressure. However, since the material is sometimes used as a heat insulating material, the heat transfer coefficient is low, and it is difficult to fill a long double hose 116 with a length of 8 m to 12 m.

Silicone oil (Comparative Example 5) has excellent internal pressure maintenance properties because it does not release pressure. However, it has low thermal conductivity and lacks heat dissipation to restrain underground power transmission cables.

On the other hand, silicone oil in which carbon filler was added (Example 1) was able to improve thermal conductivity. In the experiment, 30 g of carbon powder and 5 to 10 g of carbon black were added to 100 g of silicone oil as a carbon filler. As a result, we were able to obtain a thermal conductivity close to that of water, although not as good as that of water. This made it possible to achieve high heat dissipation and internal pressure maintenance.

Note that the carbon powder is a large particle size powder with an average particle size of about 200 μm. Carbon black is a small powder with an average particle size of about 3 to 500 nm. Carbon powder has excellent thermal conductivity, but if carbon powder is used alone, it will precipitate in silicone oil. However, precipitation can be prevented by mixing an appropriate amount of carbon black as described above. This is thought to be because the Brownian motion of the carbon black, which has become a colloidal particle, inhibits the settling of the carbon powder.

As mentioned above, as a result of the study, it is preferable that the filling material is silicone oil containing carbon filler. Thereby, high heat dissipation performance and internal pressure maintenance performance can be obtained.

FIG. 8 is a diagram illustrating another example of a double hose. FIG. 9 is a diagram illustrating the structure of the end of the inner hose 130. As shown in the perspective view of FIG. 8 and the plan view of FIG. 9(a), the inner hose 130 has an opening tube 117 formed approximately in the center of the end opening into which a member for injecting the filling material, for example, a valve 140, is inserted. has been done. The valve 140 is attached by being inserted into the open tube 117 and tightened with a hose band.

At the end opening of the inner hose 130, the sides of the open tube 117 and both sides of the open tube 117 are sealed by resin layer welding. Weld lines 180 on the sides of the open tube 117 are formed parallel to the axis of the inner hose 130 to form a tube. Weld lines 182 on both sides of the open tube 117 are obliquely inclined toward the open tube. If the weld line 182 were a straight line perpendicular to the axis of the inner hose 130, the end of the weld line 182 would be perpendicular to the side surface of the inner hose 130. Compared to this case, the stress concentration applied to the ends of the weld line 182 can be dispersed, so peeling can be prevented.

As shown in the cross-sectional view of FIG. 9(b), the inner hose 130 has a resin layer 150 disposed inside and a fiber layer 152 disposed outside. Since the double hose 116 applies pressure and restrains the cable, the inner hose 130 needs to have a sealing structure that can withstand high pressure.

As shown in FIG. 10, the inventors conducted a comparative study on several sealing structures. In Comparative Examples 6 to 8 and Example 2 in FIG. 10, the fiber layer 152 is made of aramid fiber, and the resin layer 150 is made of soft PVC (soft polyvinyl chloride). Further, FIG. 10 shows a cross section taken along the line JJ in FIG.

In Comparative Example 6, the fiber layer 152 and the resin layer 150 were integrally formed and only welded. In Comparative Example 6, the weld line 182 was cleaved at a pressure of 180 kPa. In Comparative Example 7, in addition to the structure of Comparative Example 6, it was covered with an aramid fiber cloth for reinforcement. In Comparative Example 7, pinholes occurred at a pressure of 220 kPa. In Comparative Example 8, in addition to the structure of Comparative Example 6, the weld line 182 was further sutured with a thread. In Comparative Example 8, at a pressure of 100 kPa, the sutures were not cut, but the welds were peeled off and pressure was released from the gap between the sutures 184.

On the other hand, in Example 2, as shown in FIG. 9(b), near the end of the inner hose 130, the fiber layer 152 and the resin layer 150 are separate and constitute independent sheets. Then, the resin layer 150 is linearly welded to form weld lines 180 and 182, and the resin layer 150 and the fiber layer 152 are sewn together over the weld lines 180 and 182.

In the structure of Example 2, even at a pressure of 468 kPa, no cleavage or peeling occurred, and no pressure release occurred. This is because when the resin layer 150 expands, it can shift between itself and the fiber layer 152, so the resin layer 150 stretches as a whole without being restricted by the fiber layer 152, and after the resin layer 150 expands by a predetermined amount, the fibers It is thought that this is because it is in contact with the layer 152 and pressed down from the outside, and the tension applied to the weld lines 180 and 182 can be reduced, making it difficult to peel off. This makes it difficult to cleave or peel even when the inner resin layer expands due to internal pressure, making it easier to apply high pressure and exerting sufficient cable restraining force due to high pressure.

Although 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 such examples. It is clear that those skilled in the art can come up with various changes and modifications within the scope of the claims, and these naturally fall within the technical scope of the present invention. Understood.

INDUSTRIAL APPLICATION This invention can be utilized as a cable restraint method and a double hose which restrain the cable laid in the conduit using a double hose.

100... Pipe line, 102... Manhole, 104... Cable, 106... Roadway, 108... Truck, 110... Manhole space, 112... Cable joint part, 114... Hose reversing device, 116... Double hose, 117... Open tube, 118... Vehicle, 120... Air inlet, 122... Pressure vessel, 124... Injection port, 126... Reel, 128... Outer hose, 130... Inner hose, 132... Rear end of outer hose, 134... Front end of inner hose, 136 ...Connection part, 138... Rear end of inner hose, 140... Valve, 142... Front end of outer hose, 144... Fixture, 146... Manhole entrance/exit, 148, 152... Fiber layer, 150... Resin layer, 154... Cutting device , 156a, 156b, 156c...Electric wire, 158, 158a, 158b...Gap, 160...Reversing hose, 162...Tension meter, 164...Lever block, 166...One end of cable, 168, 170...Chain, 180, 182...Welding wire , 184...suture

Claims (6)

Using a double hose that connects the front end of the inner hose to the rear end of the outer hose,
airtightly connecting the front end of the outer hose to the injection port of the hose reversing device;
introducing pressurized fluid into the outer hose using the hose reversing device to cause the outer hose to advance between the conduit and the cable while being reversed;
disconnecting the front end of the outer hose from the injection port of the hose reversing device, opening the front end of the outer hose, and exposing the rear end of the inner hose;
A method for restraining a cable, comprising injecting a filling material from the rear end of the inner hose and expanding it to restrain the cable. Either one or both of the outer hose and the inner hose is a pressure-resistant hose provided with fibers and resin,
2. The cable restraining method according to claim 1, wherein a fiber layer is disposed on the outside of the inner hose when the inner hose is inflated with the outer hose inverted. 3. The cable restraining method according to claim 1, wherein the filling material injected into the inner hose is silicone oil containing carbon filler. A double hose in which the front end of the inner hose is connected to the rear end of the outer hose,
the outer hose is inverted and overlaps the inner hose;
The inner hose becomes expandable when overlapped with the outer hose after inversion,
An anti-slip layer or a high friction layer is disposed on the inside of the outer hose before reversal and on the outside of the inner hose,
A double hose characterized in that a resin layer is disposed on the outside of the outer hose and the inside of the inner hose before inversion. The inner hose is
A resin layer is placed inside,
A fiber layer is placed on the outside,
At least the rear end of the inner hose is
The resin layer and the fiber layer are separate bodies,
A weld line is formed by linearly welding the resin layer, and
The double hose according to claim 4, wherein the resin layer and the fiber layer are sewn together at the weld line. An opening tube for injecting filling material is formed approximately in the center of the opening on the rear end surface of the inner hose,
6. The double hose according to claim 5, wherein the weld lines on both sides of the open tube are obliquely inclined toward the open tube.

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