JPS6132892B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cutting an OF cable when removing the OF cable.

When removing an existing cable from an existing conduit and then introducing a new cable into the conduit, it is necessary to cut the existing cable and then remove it. Conventionally, various methods have been proposed for removing cables, but reuse of removed cables is not intended.

By the way, when the removed cable is an OF cable, in order to reuse the removed cable, it is essential to prevent outside air from entering the cable when cutting the cable during removal.

However, when a cable is cut in an OF cable line, a situation similar to an accident with a large amount of oil leaking occurs, albeit for a short time, when the cable is cut, and the inside of the cable becomes negative pressure, causing outside air to flow into the cable. Intrusion is inevitable.

The method of cutting the OF cable when removing the OF cable according to the present invention is a method that can sufficiently prevent outside air from entering into the OF cable when cutting the cable, and crushes the OF cable part near the OF cable junction box. This method is characterized by cutting the OF cable at the crushed location.

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, 1 is a manhole, 2 is a pipe,
3 is a three-core OF cable. 4 is an ordinary junction box for OF cables, and is equipped with a semi-stop 41.

To carry out the present invention, first, the cable anti-corrosion layer near the cable junction box is peeled off, and then the cable portion 3a near the cable junction box is crushed by the compressor 5.

In the cable portion 3a near the cable junction box, normally, as shown in FIG. 2A, the cable cores 30, . Since the compressor 5 can be easily set in the proper direction with respect to the uppermost core 30', as shown in FIG. The cable portion 3a can be easily flattened by dropping the cable portion 3a.

After the cable portion 3a is crushed, the compressor 5 is removed, and the cable is cut at the central portion of the crushed portion (line bb line in FIG. 3) as shown in FIG. In this case, since the part to be cut is crushed, the leakage of cable insulating oil from the cut end is extremely small (normally it is impossible to crush the cable to a completely airtight state), and therefore the negative It is possible to sufficiently prevent pressure build-up and prevent outside air from entering into the cable.

In the above, it is also possible to crush the cable portion 3a directly from above the cable anti-corrosion layer without peeling off the cable anti-corrosion layer. In addition, if there is a sloped pipe section and there is a risk that a so-called Tortieri vacuum state may be formed in the cable due to oil spillage during the above-mentioned cutting, the construction oil tank should be placed on the other end of the cable (the first In the figure, it is desirable to connect the cable to the next cable junction box on the far left (in the figure) and replenish cable insulating oil.

In Fig. 1, 6 is a lead seater which is applied before crushing the cable portion 3a, and is used when attaching a pulling eye or a cap to the cut cable.
Do it as follows.

That is, as shown in FIG. 4, the cable end after being cut is bent upward, and
a', and as shown in Fig. 5A,
Cover the cap 7 while straddling the cap end 71.
and the lead socket part 6 may be connected by lead work (72 in FIG. 5A). Alternatively, as shown in FIG. 5B, when cutting the crushed portion end (3a' in FIG. 4), the conductors 300, . The pulling eye 7 and the lead socket part 6 may be connected by lead connection (72 in FIG. 5B).

When connecting the cap or pulling eye 7 with lead work, it is necessary to drain an appropriate amount of cable insulating oil from the connector 70 to prevent outside air from entering the cable.

FIG. 6 shows a state in which one end of the OF cable A to be removed has been cut according to the present invention, and a cap (or pulling eye) 7 has been attached in accordance with the procedure described above.

Therefore, in order to cut the other end B of the OF cable A, as shown in FIG. Close the semi-stop 41 of the cable junction box 4 on the other end of the cable. After that, the other end B of the cable near the cable junction box 4 is cut off according to the present invention, and then the pulling eye (or cap) is cut off according to the procedure described above.
Once installed, the OF cable can be removed.

In addition, in the above-mentioned example, one crushed point was provided and the cable was cut at this crushed point.
In the present invention, as shown in FIG. 7, two (or more than two) crushing locations are provided at a predetermined interval in the longitudinal direction of the cable, and crushing locations 3b and 3c are provided.
It is also possible to have a configuration in which the cable is cut between the two (portion C shown in FIG. 7). In this case, cutting the cable with the compressor still attached to the cable is effective in eliminating some recovery from swelling due to residual stress at the crushed area.

Furthermore, it goes without saying that the cutting method of the present invention can be applied to single-core OF cables as well as the above three-core OF cable.

As described above, according to the method for cutting an OF cable according to the present invention, even if an existing OF cable is cut, it is possible to keep the cut point in a state where only a small amount of oil leaks. The cable can be cut while sufficiently preventing outside air from entering into the cable.

Therefore, the OF cable that has been cut and removed according to the present invention can be easily reused since there is virtually no intrusion of outside air into the cable.
Further, in the present invention, since the cable portion on the connection box side is also configured to have a crushed portion after the cable is cut, there is an advantage that the connection box can be removed with minimal oil leakage.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the OF cable cutting method according to the present invention, FIGS. 2A and 2B are explanatory diagrams showing the cable crushing process according to the present invention, and FIG.
The figure is an explanatory diagram showing the state immediately before cutting the cable according to the present invention, Fig. 4 is an explanatory diagram showing how to attach the connector or pooling eye to the end of the cable according to the present invention, and Figs. 5A and 5B are the above-mentioned diagrams. FIG. 6 is an explanatory diagram showing the mounting structure of the connector and the mounting structure of the pulling eye.
FIG. 7 is an explanatory diagram showing a procedure for removing an OF cable, and FIG. 7 is an explanatory diagram showing a modification of the OF cable cutting method according to the present invention. In the figure, 3 is the OF cable, 4 is the connection box,
3a, 3b, and 3c are the locations where the OF cable was crushed.

Claims (1)

[Claims] 1. A method for cutting an OF cable when removing an OF cable, characterized by crushing a portion of the OF cable near an OF cable junction box and cutting the OF cable at the crushed portion. 2. The method for cutting an OF cable when removing an OF cable according to claim 1, wherein at least two crushed locations are provided at a predetermined interval in the longitudinal direction of the cable.