JPH0650927B2 - Thermal expansion suppression device for cable offset part - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to suppressing thermal expansion and contraction applied to an offset portion set in a human hole portion where an electric power cable laid in a pipeline projects from a pipeline opening. Regarding the improvement of the device.

[Conventional technology]

Generally, in a power cable installed in a pipeline, the manhole is pulled out with a predetermined offset and connected to a junction box installed in the manhole.

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. 4, this device has a split ring A having a slit in the vertical direction with respect to a taper converging downward, and a split ring B having a slit in the lateral direction with respect to the same taper. , By alternately arranging on the circumference of the offset portion of the cable C and inserting it, a series of slits of adjacent rings intersect,
The tension member T is skewered on the split ring continuously provided in this way, and both ends of the tension member T are fixed to the restraint fittings.

By doing so, the movement of the offset portion of the cable C is suppressed by the structure of the split rings A and B which are skewered to the tension member T and restrain the movement of the rings with each other and which are bent and pipe-shaped due to the abutment of the tapered side surfaces. To be done.

[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 determined by the offset dimension does not match the calculated value with the actual value, and the split ring is manufactured according to the calculated bending radius, so it can be used as a predetermined curved pipe line on site. Assembling becomes difficult, and a large amount of adjustment work is required, so improvement in work efficiency cannot be expected.

Further, assembling such a split ring requires careful and skilled work such as confirmation of the direction of the ring and a device for attaching 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.

In view of the above problems, the present invention provides a heat expansion / contraction device for a cable offset portion, which enables centralization and generalization of rings for offset portions having different curvatures, and which can be easily constructed locally and in a short time. The purpose is to

[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 large number of rings spaced apart from each other and distributed and surrounded in various places in the longitudinal direction of the cable offset portion, and screw grooves are engraved over the entire length, and A plurality of split rings are sewn together as a skewer, and a reinforcing rod that holds both ends is retained.By tightening nuts screwed to the reinforcing rod on both side surfaces of each ring, It is separately positioned and fixed, and each ring can be fixed at an arbitrary position of the reinforcing rod only by operating the nut.

[Action]

According to the thermal expansion and contraction suppressing device of the present invention, the distribution of a large number of rings skewered to the reinforcing rod can be adjusted and positioned and fixed by the screwing operation of the nut screwed to the reinforcing rod. The ring can be set at a position along the offset shape of the cable, which often has a different curvature depending on the space or the like, without exchanging the ring. According to this, it is possible to use the same ring that surrounds the cable in various places in its longitudinal direction, and it is possible to unify and generalize the ring precisely manufactured in a complicated shape by casting or the like. .

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 rod is realistic as the reinforcing rod.

〔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 6 installed on the inner wall of the human hole is provided, and a fixing metal fitting 7 installed on the bottom wall of the human hole in the vicinity of the connection box 5 is provided. , 7, a thermal expansion / contraction suppressing device 8 is provided for the cable offset portion 4.

Therefore, the thermal expansion and contraction suppressing device 8 has a large number of rings 9 which are dispersedly arranged with respect to the cable offset portion 4 along the connecting arc-shaped curve of the offset shape.
It is equipped with 9, 9 ,.

The plurality of rings 9, 9, 9 ... Enclose the connecting arc-shaped curved cable portion at a position having an equal interval in the longitudinal direction with respect to the offset shape portion 4 of the cable,
It serves to restrain the movement of the offset-shaped portion 4 due to thermal expansion and contraction.

Further, each ring 9, 9, 9 ... Is made into a series by inserting a reinforcing rod 10 made of a tensile strength rod into the skewer at a symmetrical position with respect to the axis of the cable through hole. .

The reinforcing rod 10 has a screw groove formed in its entire length, and nuts 11 and 11 are screwed from the front and the rear of the ring 9 as shown in FIGS. 2 and 3.

Therefore, it is possible to axially move and positionally fix the ring 9 to the reinforcing rod 10 by screwing the nuts 11 and 11.

Therefore, it is possible to obtain ring arrangement configurations corresponding to offset shapes with various curvatures only by adjusting the positions of the rings 9, 9, 9 ... By operating the nuts.

The reinforcing rods 10 and 10 are fixed to both ends by screwing or inserting the ends into the fixing metal fittings 6 on the conduit opening side and the fixing metal fittings 7 on the connection box side and tightening them by nuts. Each ring 9, which is placed vertically along the offset-shaped portion 4 while providing a predetermined tension between the metal fittings 6 and 7, is accompanied by a skewer on the reinforcing rod 10 and is positioned and fixed by the nuts 11 and 11. 9,
9 are distributed and enclosed in various places of the osset-shaped portion 4 along the connecting arc-shaped curve of the offset-shaped portion 4 at intervals to suppress the deformation motion of the offset-shaped portion 4. The pipeline is built.

As shown in FIG. 3, each ring 9 can be put in a state of surrounding the laid cable by making a half-divided ring face each other with the cable sandwiched therebetween and fastening them with bolts and nuts.

The ring 9 is a reinforcement rod 1 after it is attached to the cable.
Although 0 may be skewered, according to the present embodiment, it is possible to provide a method that can more easily be mounted on the offset-shaped portion by using the half ring.

That is, a large number of half rings are used as skewered reinforcing rods with screw grooves, and each ring is positioned and fixed with a nut to form a set of half units separately.

Such half-units can be pre-built on the factory side. In that case, each ring is positioned by operating the nut based on the design value of the connecting arc-shaped curve of the offset shape portion of the cable.

The half unit loaded as described above is bent so as to form a connecting arc-shaped curve of the offset shape portion 4, and is made to face each other with the offset shape portion 4 sandwiched therebetween, and the half rings that are opposed to each other are arranged. By fastening with bolts and nuts, a ring 9 that surrounds the cable is formed, and subsequently, both ends of the reinforcing rod 10 are fixed to the fixing brackets 6, 7.
It suffices to fix the reinforcing rod by tightening the nut and tightening the nut.

In this way, in the human hole, it is possible to construct by a simple operation of joining and joining the half rings and retracting the end of the reinforcing rod.

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 apparatus for suppressing thermal expansion and contraction of the cable offset portion of the present invention described above, the reinforcing rod that is easily available is screw groove processed without making many types of rings manufactured by the casting method or the like. Since the ring is fixedly positioned and fixed with a nut that is screwed to, it is possible to fix each ring to any position of the reinforcing rod only by operating the nut and apply it to offset shaped parts with various design curvatures. The number of rings is unified and generalized without increasing or reducing (processing) the number of parts to adjust the number, and contributes to the cost reduction of the part.

Therefore, for the offset part with different curvature, it is possible to unify and generalize the ring, and at the same time, the initial objective of providing a thermal expansion and contraction device for the cable offset part that can be easily built on site and in a short time is achieved. Therefore, it is possible to provide this kind of thermal expansion and contraction suppressing device which is economically advantageous and has a large actual profit.

[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, FIG. 2 is a front view explanatory view showing an essential part of the same device, and FIG. 3 is an essential part of the same device. FIG. 4 is an explanatory perspective view showing the example, and FIG. 4 is an explanatory view showing an example of a conventional offset portion reinforcing device to which a stop ring is applied. 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, 6 and 7 are fixing fittings, 8 is a heat expansion and contraction suppressing device, 9 is a ring, 10 is a reinforcing rod, and 11 is a nut.

 ─────────────────────────────────────────────────── ─── 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 Factory (72) Inventor Shiro Tanno 5-1, 1-1 Hidaka-cho, Hitachi City, Ibaraki Hitachi Cable Electric Wire Co., Ltd. (56) Reference June 20, 1989 An article titled "Chubu Electric Power Challenge Activity in the 6th year" of "Denki Shinmon" edited by the New Mechanical Engineering Handbook Editorial Committee, "New Mechanical Engineering Handbook" (May 15, 1973), published by RIKEN. Volume 2 4-4-4-11

Claims (1)

[Claims] 1. A large number of rings spaced apart from each other and distributed and surrounded at various places in the longitudinal direction of a cable offset portion, and a reinforcing rod in which screw grooves are engraved along the entire length and the plurality of rings are skewered together. Each ring is individually positioned and fixed by pressing the nuts screwed to this reinforcing rod on both sides of each ring, and each ring can be positioned at any position of the reinforcing rod by only operating the nut. A device for suppressing thermal expansion and contraction of a cable offset portion, which can be fixed.