JPH0990185A - Installation method for optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an installation method of an optical fiber cable, which transfers the new optical fiber cable by pressure in a communication pipe where the optical fiber cable is previously installed inside. SOLUTION: In the installation method of the optical fiber cable for transferring with pressure and installing the optical fiber cable in the communication pipe which is previously installed by using fluid, a branching pipe 21 having plural incoming line parts is provided for the communication pipe 1 where more than one optical fiber cable 4 is previously installed inside, and one incoming line port of the branching pipe 21 restricts the installed optical fiber cable 4 in a branching communication pipe 3a connected to one of the incoming line ports of the branching pipe 21 or the pertinent incoming line port. More than one new optical fiber cable 5 is transferred with pressure and installed in the communication pipe 3b through the other incoming line port of the branching pipe 21a at an arbitrary period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the laying of an optical fiber cable for newly laying one or more optical fiber cables in a pipe for passage, in which one or more optical fiber cables are already laid inside. It is related to the construction method.

[0002]

2. Description of the Related Art A pipe for wiring, which is laid in advance and has nothing inserted therein, or a composite power cable constructed by twisting a plurality of such pipes and cores of a power cable. A so-called ABF method has already been known, in which a fluid such as compressed air is used in a conduit pipe to pressure-feed an optical fiber cable. This method not only allows laying of optical fiber cables at any time, but also allows easy removal, so flexible operation such as adding optical fiber cables or replacing them in response to fluctuations in demand Therefore, it is expected that the construction cost of the optical transmission line can be significantly reduced.

[0003]

[Problems to be Solved by the Invention] However, the current ABF
In the construction method, since only one optical fiber cable is pumped to one passage pipe, for example, in the case of the transmission line configuration shown in FIG. 2, the passage pipes are concentrated in a specific section. However, there was a problem that the space factor was lowered and the aesthetics was damaged.

In the current ABF method, the reason why only one optical fiber cable is pressure-fed to one passage pipe is as follows. (1) When a fluid is flown to lay a new optical fiber cable in a conduit pipe where an optical fiber cable is already laid, the existing optical fiber cable comes out of the pipe outlet due to fluid pressure. (2) Even if measures were taken to prevent the existing optical fiber cable from slipping out, it was thought that the existing optical fiber cable would be an obstacle and additional optical fiber cables could not be additionally pumped.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and makes it possible to pump a novel optical fiber cable to a conduit pipe in which the optical fiber cable is already laid. The present invention provides a method for laying a branch pipe having a plurality of inlets in a pipe for wiring, in which one or more optical fiber cables are already laid inside, and one of the branch pipes is provided. 1 or a new optical fiber cable is provided in the branch pipe through the other entrance of the branch pipe, by restraining the existing optical fiber cable to the branch or the branch conduit pipe connected to the entrance port. It is a method of laying optical fiber cables in which the above-mentioned strips are laid under pressure at any time.

[0006]

1 is an explanatory view of a concrete example of a method of laying an optical fiber cable according to the present invention. As shown in the drawing, a branch pipe 2 having a plurality of wire inlets 2a and 2b is connected to one end of a plastic wire-conducting pipe 1, and the end portions of the respective wire inlets 2a and 2b are connected to each other. Branch pipes 3a, 3b made of plastic and having the same inner diameter as the wire pipe 1 or a smaller inner diameter than this are connected. In the embodiment shown in FIG. 1, the branch pipe 2 is provided at one end in advance, but it goes without saying that the branch pipe 2 may be provided at any time.

In the pipe system as described above, the optical fiber cable 4 is already provided in the conduit pipe 1 through the branch conduit pipe 3a and one branch port 2a of the branch pipe 2.
Has been laid. As described above, when an additional optical fiber cable is newly installed in the conduit pipe 1 in which the existing optical fiber cable 4 is installed, the existing optical fiber cable 4 is connected to the end of the branch conduit pipe 3a. , Or if there is no branch passage pipe 3a, the entry port 2 of the branch pipe 2
At a, the existing optical fiber cable 4 is restrained using the restraint member 8 so as not to come out. Then, the new optical fiber cable 5 wound around the drum 7 by the pressure feeding head 6 is installed in the conduit pipe 1 through the branch conduit pipe 3b and the other inlet port 2b of the branch pipe 2.

FIG. 5 is a vertical sectional view of an example of the restraint member 8. As shown in the drawing, a hollow bolt 12 having the outer periphery thereof screwed into the optical fiber cable 4 is attached to the end of the conduit pipe 11 on which the optical fiber cable 4 has already been laid. A tapered bushing that passes through the optical fiber cable 4 is inserted. Then, the tightening nut 14 having a thread from the outside to the inner circumference is screwed into the screw on the outer circumference of the hollow bolt 12 and restrains the existing optical fiber cable 4 to the end of the conduit pipe 11. The restraint member shown in FIG. 5 is an example, and its structure and shape are not particularly limited as long as it has the same function. The binding force should be 2 g or more.

FIG. 6 (a) is a front view of an example of the branch pipe 2, FIG. 6 (b) is a left side view of FIG. 6 (a), and FIG. 6 (c).
6 is a right side view of FIG. As shown in the drawing, the radius of curvature of the branch pipe must be 30 mmR or more.
FIG. 7 also shows an example of the branch pipe 2, but in the same figure, the branch pipe 2 is divided into the branch pipe 2 with the existing optical fiber cable being routed through the conduit pipe 1. It has a two-split structure so that it can be attached. It should be noted that FIG.
Is a front view, FIG. 7B is a left side view of FIG.
FIG. 7C is a right side view of FIG.

[0010]

In the optical fiber cable laying method of the present invention described above, when a novel optical fiber cable is laid by pressure, the optical fiber cable already laid inside the conduit pipe is restrained at the pipe end or the like. As a result, it is possible to prevent the new optical fiber cable from coming off due to fluid pressure or the like during pressure feeding. Since the new optical fiber cable is pumped through the open inlet of the branch pipe provided at the end of the conduit, the existing optical fiber cable does not become an obstacle at the inlet.

As described above, since it is possible to lay a plurality of optical fiber cables on one line pipe,
The required number of pipes can be reduced and the aesthetics can be improved. For example, in the laying system as shown in FIG. 2, many optical fiber cables (6 lines in the figure) are concentrated near the terminal station A. In this case, in the conventional method, six passage pipes 1 are required as shown in FIG. 3, whereas in the method of the present invention, the number of pipes is 1/3 (or 1 /) as shown in FIG.
2), the laying form of the pipe becomes compact, and the aesthetic appearance is improved.

[0012]

[Experimental Example 1] As shown in FIG. 8, a passage pipe 1 is formed in a coil shape having a diameter of about 1 m, and a branch pipe 2 having a plurality of inlets is provided at an end thereof, and each inlet is provided with a branch pipe 2. A branch passage pipe 3 is connected. One or more optical fiber cables 4 have already been laid on the conduit 1 for wiring. In this way, the existing optical fiber cable 4 laid in the conduit pipe 1 is constrained at the end of the branch conduit pipe 3 and passes through the vacant branch conduit pipe and the branch pipe 2 entry port. A new optical fiber cable 5 was laid under pressure in the conduit 1 by a pressure feed head 6. The results are shown in Tables 1 and 2.

[0013]

[Table 1]

[0014]

[Table 2]

As can be seen from the above Tables 1 and 2, if the existing optical fiber cable is 1 piece, the length of the pipe for wire passage is 400
It is possible to add up to 200 m, and if the existing optical fiber cable is 2 strips, the pipe length can be added up to 200 m, and there is no problem in practical use (it is thought that a length of 150 m or more can be sent over a continuous length). Was confirmed.

[0016]

[Experimental Example 2] In FIG. 8, the branch pipe 2 was constructed with various bending diameters, and the time required for laying under pressure was measured. However, the length of the pipe was 200 m, and the existing optical fiber cable had 1 and 2 sections. The results are shown in Table 3. As can be seen from the results in Table 3, there are cases where the bending diameter of the branch pipe is 25 mmR, but there are cases where the full length cannot be pumped at 30 mmR.

[0017]

[Table 3]

[0018]

As described above, according to the method of laying an optical fiber cable of the present invention, it is possible to lay a plurality of optical fiber cables in a single conduit pipe. Therefore, for example, like a transmission line for an optical multi-drop system, in the vicinity of a terminal station where a large number of optical fiber cables are concentrated, it is possible to reduce the number of pipes for passage, and the laying form of the pipes becomes compact, The aesthetics are improved.

[Brief description of drawings]

FIG. 1 is an explanatory view of a concrete example of a method for laying an optical fiber cable according to the present invention.

FIG. 2 is an explanatory diagram of an example of a system for laying a conduit pipe.

FIG. 3 is an explanatory diagram of an example of a configuration of a conduit pipe according to a conventional method.

FIG. 4 is an explanatory diagram showing an example of a structure of a conduit pipe according to the method of the present invention.

FIG. 5 is a vertical sectional view of an example of an optical fiber cable restraining member.

6 (a) is a front view of an example of a branch pipe, FIG.
6B is a left side view of FIG. 6A, and FIG. 6C is of FIG.
It is a right view of (a).

7 (a) is a front view of another example of the branch pipe, FIG. 7 (b) is a left side view of FIG. 7 (a), and FIG. 7 (c) is FIG.
It is a right view of (a).

FIG. 8 is an explanatory diagram of an experimental example of the method of the present invention.

[Explanation of symbols]

 1 conduit pipe 2 branch pipes 2a, 2b branch pipe inlet 3a, 3b branch conduit pipe 4 existing optical fiber cable 5 new optical fiber cable 6 pressure feed head 7 drum 8 restraining member

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[Procedure amendment]

[Submission date] January 16, 1996

[Procedure Amendment 1]

[Document name to be amended] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction contents]

FIG. 7

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirofumi Tayama 3-3-22 Nakanoshima, Kita-ku, Osaka City Kansai Electric Power Co., Inc. (72) Yuichi Tamada 3-3-22 Nakanoshima, Kita-ku, Osaka Kansai Electric Power Co., Inc.

Claims (1)

[Claims] 1. A method of laying an optical fiber cable in which a fluid is used to pressure feed the optical fiber cable into a previously installed conduit pipe, wherein one or more optical fiber cables are already laid inside. A branch pipe having a plurality of inlets is provided on the conduit pipe, and the existing optical fiber cable is constrained to one inlet of the branch pipe or a branch conduit pipe connected to the inlet, A method for laying an optical fiber cable, characterized in that one or more new optical fiber cables are pressure-fed at an arbitrary time into the pipe for passage through another inlet of the branch pipe.