JPH0650926B2 - Device for suppressing thermal expansion and contraction of cable offset portion and method for constructing the device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a heat expansion / contraction suppressing device and a method of constructing a heat expansion / contraction suppressing device for an offset portion where an electric power cable laid in a pipeline is set in an inlet portion. Regarding

[Conventional technology]

Generally, in a power cable installed in a pipeline, a connection portion is provided in the manhole by pulling out the manhole with a predetermined offset.

In recent years, it has been considered to lay an electric power cable using an existing pipeline, and in that case, there is no room in the human hole portion, and the offset shape may be restricted. In that case, it is necessary for the offset portion to suppress the bulge due to the extension of the cable when the cable is energized, and some proposals have been made to cope with this.

As one of them, a cable offset reinforcing device using a split ring has been proposed.

That is, as shown in FIG. 7, this device has a split ring a having a slit in the longitudinal direction with respect to a taper converging in one direction, and a split ring b having a slit in the lateral direction with respect to a similar taper. As shown in FIG. 6, the slits of the adjacent rings are made to intersect by alternately arranging and inserting the cables on the circumference of the offset portion of the cable C, and the tension members are connected to the split rings continuously arranged in this manner. T was skewered, and both ends of the tension member T were fixed to the restraint fittings to form a series.

By doing so, the movement of the offset portion of the cable C can be prevented by the structure of the split rings a and b that are skewered to the tension member T and the movements of the rings are restrained and the curved side is formed by the abutment of the tapered side surfaces. Suppressed.

[Problems to be Solved by the Invention]

The bending radius of the cable may vary depending on the size of the offset portion, and it is necessary to manufacture a corresponding split ring for each different bending radius of the cable.

There are at least 3 types of cable bending radii when laying one line and at most 6 types of bending radii when two lines are laid, and it is necessary to manufacture each split ring accordingly, which leads to economical production with a large number of small quantities. It was a disadvantage.

In addition, the cable bending radius that is determined by the offset dimension almost does not match the calculated value and the actual value,
Since the split ring is manufactured in accordance with the bending radius based on the calculated value, it becomes difficult to assemble the pipe as a predetermined curved pipe on site, and a large amount of adjustment work is required, and improvement in work efficiency cannot be expected. Further, assembling such a split ring requires careful and highly skilled work such as confirmation of the direction of the ring and the position of attachment to the cable.

Further, according to such a split ring, since the split rings having two different slits restrain the radial movements of each other based on the skewers of the tension members, all of them are narrow in the field (in the human hole). It had to be constructed with a lot of man-hours at the place.

Furthermore, when the split ring is attached, the offset shape part of the cable is almost hidden, and it becomes impossible to check whether the offset shape part has local bending, and even if an abnormality occurs, it is easy to delay discovery. It was not desirable for maintenance and monitoring.

In view of the above-mentioned circumstances, the present invention aims at unifying and generalizing rings that require time to manufacture, can be easily constructed locally and can be performed in a short time, and is also advantageous in maintenance monitoring. It is an object to provide a heat expansion / contraction device and a method for constructing the device.

[Means for Solving the Problems]

According to the present invention, the thermal expansion and contraction suppressing device for achieving the above object is provided with a plurality of rings surrounding the cable offset portion in places in the longitudinal direction, and around the cable between adjacent rings. A large number of spacing pipes that are arranged in the state of being dispersed along the lengthwise direction so as to separate adjacent rings so that they do not contact each other, and a large number of intermediate rings and spacings that are alternately arranged as described above. It has a tension member that makes a series of pipes and skewers, and the axial end faces of the spacing pipes are brought into contact with the side faces of each ring, so that the spacing between adjacent rings depends on the selected length of the spacing pipes. Is set and a positive gap is formed between any two adjacent rings so that the cable can be seen.

Further, as a method of constructing a heat expansion and contraction suppressing device for achieving the above-mentioned object, a large number of half rings and spacing pipes are alternately arranged and assembled in a state of being preliminarily arranged in a skewered manner with tension members. Prepare a pair of half units, make the pair of half units face each other across the cable offset part, and fasten the half rings that are facing each other from the positions separated by the interposition of the space holding pipe to lengthen the cable in the longitudinal direction. Of the tension members at both ends of each half-unit to retain it in a series.

A preferred embodiment of the ring is composed of a terminal ring that is connected and fixed to a fixing device installed on the end side of the cable offset portion, and a large number of intermediate rings that are connected between the both end rings via spacing pipes. Then, both ends of the tension member that penetrates the skewer with a large number of intermediate rings and spacing pipes are anchored and fixed to the end rings on both sides to form a series.

[Action]

According to the heat expansion and contraction suppressing device of the present invention, each ring is offset by connecting arcs of the cable by simply selecting the length of the spacing pipe which is very easily available and whose length can be specified by simple cutting. It can be set at a position along the shape. According to this, the same ring can be used for all the rings surrounding the cable in the longitudinal direction, and the rings can be precisely manufactured in a complicated shape by casting or the like.

Further, it is possible to adapt to the cable offset portion of any bending radius by simply changing the length of the spacing pipe without changing the ring, so that the ring can be generalized.

Further, according to the heat expansion and contraction device of the present invention, the cable can be seen through between the adjacent rings that are spaced apart by the interposition of the interval holding pipes and between the interval holding pipes that are distributed around the cable, It is possible to monitor directly from outside the device.

In addition, according to the construction method of the present invention, a half unit is assembled in advance by alternately tensioning members on the alternating connection body of the half ring and the interval holding pipe at the factory side or the installation site (in the human hole). It can be built in a large place outside, and it can be carried into the field (inside the human hole) and face each other so as to sandwich the offset part of the cable, and the opposite half-rings can be fastened together to secure the end of the tension member. A predetermined thermal expansion and contraction suppressing device can be constructed only by the work process of fastening the fixing metal fitting.

Since a cable in which thermal expansion and contraction is a problem is usually a single-core cable, a non-magnetic metal such as aluminum or stainless steel is used or a fiber reinforced plastic is used to prevent heat generation due to induction from the cable. (FR
It is desirable to use P). The terminal ring and the intermediate ring are made of aluminum die-cast, and a stainless steel pipe or a FRP pipe is practical as the space keeping pipe.

〔Example〕

FIG. 1 shows a preferred embodiment of a thermal expansion and contraction suppressing device for a cable offset portion according to the present invention.
Reference numeral 1 is a pipe line, and 2 is a power cable passed through the pipe line. The power cable is taken out by taking a predetermined offset shape 4 into a human hole 3 forming a pipe mouth, and is terminated in a connection box 5. At the conduit opening, a fixing metal fitting 7 installed by a bracket 6 is provided on the inner wall of the human hole, and a fixing metal fitting 9 installed by a bracket 8 or the like is provided on the bottom wall of the human eye near the junction box 5. A heat expansion / contraction suppressing device 10 is provided for the cable offset portion 4 between the two fixing fittings 7 and 9.

Therefore, the thermal expansion and contraction suppressing device 10 is configured such that, with respect to the cable offset portion 4, the conduit opening portion and the connection box 5 which are the end portions thereof.
, And a large number of intermediate rings 12, 12 arranged along the offset arc-shaped connecting arc-shaped line between the end rings 11, 11.
12 ... and the terminal rings 11 and 11 are
The end of the offset shape of the cable 2 is surrounded by abutting its own flange or the like on the fixing metal fittings 7 and 9 and fastening them with a bolt nut or the like, and the pipe opening side and the connection box 5 side are arranged in the radial direction with respect to the cable. I try to restrain the movement to.

On the other hand, the intermediate rings 12, 12, 12, ... Enclose the connecting arc-shaped curved cable portions at positions that are evenly spaced in the longitudinal direction with respect to the offset-shaped portion 4 of the cable, and the offset-shaped portion 4 It is used to restrain the movement due to thermal expansion and contraction.

A large number of intermediate rings 12, 12, 12, ... Are formed as a series by inserting tension members 13, 13 made of tensile strength wires into skewers at positions symmetrical with respect to each ring with respect to the axis of the cable passage hole. In addition, each tension member 1 is provided between each of the adjacent intermediate rings 12, 12.
The long and narrow spacing pipes 14 and 14 inserted in 3 and 13 are interposed, and both ends of the pipes 14 contact the side surfaces of the intermediate rings 12 and 12 to prevent movement of the rings 12 and 12 in the cable longitudinal direction. Then, the offset shape portion can be surrounded at a predetermined position.

The tension members 13 and 13 have their ends inserted with the space holding pipes 15 and 15, respectively, and
By piercing through the flange of 1 and threading the nuts 16 and 16 and adjusting the tightening from the terminal side, a predetermined tension is given between the terminal rings 11 and 11 in a state of being anchored and fixed, whereby , Both terminal rings 11, 11
A large number of spacing spacers 14 and 15 and the intermediate ring 1 between
2 and 2 are alternately contacted to form a series of beads.

As in this embodiment, the tension member 1 is attached to the offset-shaped portion 4 of the cable which is S-shaped in the longitudinal direction.
When 3 and 13 are extended in the longitudinal direction at positions along the top and bottom, there are portions with different radii of curvature in the upper and lower tension members 13 and 13, respectively, so that the tension member 13 of the intermediate ring 12 is inserted therethrough. The distance between the outward flanges 12a is also different.

According to the present invention, such a case can be dealt with by specifying the length of the interval holding pipe 14.

That is, the adjacent intermediate rings 12, 12 having a small radius of curvature
In the portion where the flanges of the two are close to each other, a short interval holding pipe is used, and the intermediate rings 12, which have a large radius of curvature and are adjacent to each other,
In the portion where the flange of 12 is widened, it is possible to form a good contact state between the pipe and each ring by using a longer spacing pipe.

The spacing pipes having different lengths as described above can be obtained by simply cutting a metal pipe into a predetermined length.

The terminal ring 11 and the intermediate ring 12 can be made to be in a state of surrounding the laid cable by making the halved pieces face each other across the cable and fastening them with bolts and nuts.

Although the tension member 13 may be skewered after the rings 11 and 12 are attached to the cable, the present invention provides a method for easily attaching to the offset shape portion by using the half ring. be able to.

FIG. 2 shows a preferred embodiment of a method for constructing a heat expansion / contraction device for such an offset portion of a cable, which comprises a large number of half-divided intermediate rings 12 ₁ , 12 ₁ , 12 _1.
... and a large number of spacing pipes 14 ₁ , 14 ₁ , 14 ₁ ...
・ Alternatively arrange and tension member 13
And ₁ to skewer and a series of things, the tension member 1
3 ₁ and half unit 17 to set the nut 16, 16 is screwed to both ends of the, in the same manner, a number of half intermediate ring 12 _2, 12 _{2, 12} 2, ... and a number of spacing pipe 14 ₂ and 14 ₂ and 14 ₂ are alternately arranged, and tension members 13 ₂ are skewered on them to form a series, and nuts 16 and 1 are attached to both ends of the tension members 13 _2.
The half unit 18 in which 6 is screwed to form a set is previously constructed.

FIG. 3 shows the half-divided intermediate rings 12 ₁ and 12 ₂ for each of the half units 17 and 18,
The flange 12a formed on the outer peripheral surface of the ring body 120 which is so shaped in a semicircular shape to have the groove for passing the cable on the opposite side, the spacing holding pipe 14 here _1, 14 ₂
Through holes for abutting and piercing the tension members 13 ₁ and 13 ₂ .

Further, the flanges 12 with through holes facing each other are provided at both ends.
b, 12b are formed, these flanges 12b,
A predetermined ring 12 is formed by passing a bolt through 12b and tightening it with a nut.

Such half units 17, 18 can be constructed on the factory side. In that case, the spacing pipe 14 ₁ ,
14 _2, the length based on the design value of the connecting arc-shaped curve of the offset shape of the cable is determined. The half units 17 and 18 can be used for transportation by straightening them by adjusting the tightening of the nuts 16 and 16 or by appropriately bending them.

The half units 17 and 18 carried in as described above are
Bent so that the connecting arc-shaped curve of the offset shape portion 4 of the cable 2 by tightening adjustment of the nut 16 and 16, are opposed dressed sandwiching the offset shaped part 4, halved intermediate ring 12 ₁ each mutually opposed 1 and 12 ₂ by fastening their own flanges 12b, 12b to each other with bolts and nuts, a ring 1 for enclosing a cable
2, which is followed by tension member 13
_1, 13 ₂ at both ends, the nuts 16, 16 once removed, causes inserted under the spacing holding pipe 15, as shown in FIG. 1, the terminal ring 11 which is fixedly connected to a separate fixing bracket 7,9 therewith, By inserting into the flange 11a of 11 and tightening the nuts 16 and 16 removed from the end side, the terminal rings 11 and 11 are withdrawn and fixed, and the thermal expansion / contraction device 10 similar to that of FIG. 1 is constructed.

As described above, according to the present embodiment, it is possible to construct the inside of the human hole by a simple operation of joining and joining the half rings and retracting the terminal of the tension member.

It is possible that the actual connecting arc of the offset profile 4 of the cable is significantly different from that of the design value.
Even in such a case, the present invention can be easily dealt with by either cutting the space maintaining pipes down or adding an appropriate space maintaining member to the gap portion.

FIG. 4 shows an example of coping with such a case, in which the length of the spacing pipe 14n interposed between the adjacent half rings 12n and 21n becomes insufficient. A C-shaped ring 19 (see FIG. 5) having a width sufficient to fill the generated gap G is fitted to the exposed tension member 13.

The above C-shaped ring is used when the same size as the heat expansion and contraction device applied to the former is applied to another cable offset part where the design value of the connecting arc curve of the offset shape part of the cable is similar. be able to.

When the thermal expansion and contraction control device is constructed by the above method, it is possible to reduce the work time at the site (in the human hole) by about 70% compared to the method using the split ring as shown in FIG. is there.

Note that the thermal expansion and contraction suppressing device of the present invention suppresses expansion and contraction of the cable when it is energized, but it can also function as a movement restraint device for the cable when the cable slips or surfing occurs. it can.

〔The invention's effect〕

According to the device for suppressing thermal expansion and contraction of the cable offset portion and the method for constructing the device of the present invention described above, it is possible to easily obtain an interval holding pipe without making many types of rings manufactured by a casting method or the like. Since it can be applied to the offset shape part having various design curvatures by specifying the length, it is possible to unify and generalize a large number of rings and contribute to the cost reduction of parts.

By dividing the ring surrounding the offset shape part of the cable at a predetermined interval in half and preliminarily constructing a half unit in which the half ring and the interval holding pipe are made into a series by skewering tension members, Assembling time and man-hours are greatly reduced, and a predetermined device can be constructed by fastening work with bolts and nuts etc. between half rings and terminal retention of tension members, so that there is no space in the field (in the human hole). Work becomes easy. In addition, it also contributes to cost reduction related to on-site work. In addition, if the half unit is built in advance at the factory side, it is possible to eliminate defects due to assembly mistakes and the need for rebuilding, and to improve quality.

Since the offset portion of the cable is exposed between the adjacent rings of the multiple rings and also between the spacing pipes distributed around the cable, the state of the offset portion can be visually or tactually felt even after the device is attached. Even if an abnormality occurs in the offset shape portion, it can be found early.

It is possible to provide this kind of thermal expansion and contraction suppressing device and method which have the above-mentioned effects, and therefore the original purpose is sufficiently achieved, and which is generally economically advantageous and practically profitable.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a heat expansion / contraction device for a cable offset portion according to the present invention, and FIG. 2 is an explanatory view showing an embodiment of a method for constructing a heat expansion / contraction suppressing device according to the present invention. FIG. 4 is a perspective explanatory view showing an example of a half-divided intermediate ring adopted in the method or apparatus, FIG. 4 is an explanatory view showing an example of a ring, a spacing pipe, and an adjusting method in the method or apparatus, and FIG. FIG. 6 is an explanatory view of a correction ring used in the method, FIG. 6 is an explanatory view of a split ring applied to a conventional device of this kind, and FIG. 7 is an example of a conventional offset portion reinforcing device to which the stop ring is applied. It is an explanatory view shown. In the figure, 1 is a conduit, 2 is a cable, 3 is a human hole, 4
Is an offset shape part, 5 is a connection box, 7 and 9 are fixing fittings, 10 is a thermal expansion and contraction suppressing device, 11 is a terminal ring, 12,
12n is an intermediate ring, 13, 13 ₁ , 13 ₂ and 13n are tension members, 14, 14n and 15 are spacing pipes, and 17 and 18 are half units.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Osamu Kito 1 Higashishinmachi, Higashi-ku, Nagoya, Aichi Prefecture Chubu Electric Power Co., Inc. (72) Inventor Satoshi Minagawa 5-1-1, Hidakacho, Hitachi-shi, Ibaraki Hitachi Electric Wire Co., Ltd. Hidaka Plant (72) Inventor Hiroshi Kamoshida 5-1-1 Hidakacho, Hitachi City, Ibaraki Hitachi Cable Electric Wire Co., Ltd. (56) Reference JP-A-61-102114 (JP, A) Actual public Sho 55-14034 (JP, Y2)

Claims (4)

[Claims] 1. A large number of rings surrounding the cable in the longitudinal direction with respect to an offset portion of the cable, and interveningly arranged along the longitudinal direction in a state of being dispersed around the cable between adjacent rings. By so doing, a large number of spacing pipes that separate adjacent rings so that they do not contact each other, and a tension member that is a series of a large number of intermediate rings and spacing pipes that are alternately arranged as described above are skewered. The distance between the adjacent rings is set depending on the selected length of the distance maintaining pipe by abutting the axial end surface of the distance maintaining pipe on the side surface of each ring. A heat expansion and contraction suppressing device for a cable offset portion, which is characterized in that a positive gap is formed so that the cable can be seen. 2. The ring comprises a terminal ring which is connected and fixed to a fixing device installed on the end side of the cable offset portion, and a plurality of intermediate rings which are continuously arranged between the both end rings via a space holding pipe. And tensioning members at both ends of the tension member, which penetrates the skewer with a large number of intermediate rings and spacing pipes, are retained and fixed to the terminal rings on both sides.
(1) The device for suppressing thermal expansion and contraction of the cable offset portion. 3. A pair of half units assembled in a state in which a large number of half rings and spacing pipes are arranged alternately and skewered by tension members to be pre-connected to each other,
The pair of half units are opposed to each other with the cable offset portion interposed therebetween, and the half rings that are opposed to each other are fastened to each other from positions separated by the interposition of the spacing pipe to surround the cable partially in the longitudinal direction. A method for constructing a thermal expansion and contraction suppressing device for a cable offset portion, characterized in that the ends of tension members are retained at both ends of the half unit to form a series. 4. The ring comprises a terminal ring which is connected and fixed to a fixing device installed on the end side of the cable offset portion, and a plurality of intermediate rings which are continuously provided between the both end rings via a space holding pipe. And tensioning members at both ends of the tension member, which penetrates the skewer with a large number of intermediate rings and spacing pipes, are retained and fixed to the terminal rings on both sides.
(3) The method for constructing the cable offset heat expansion / contraction suppressing device described in (3).