JPH0618721A - Optical fiber cable with freezing hazard preventive pipe and laying method therefor - Google Patents

Abstract

PURPOSE:To eliminate troubles, such as clogging of a pipeline, at the time of laying by previously bundling and integrating an optical fiber cable and freezing hazard preventive pipes by means of binders. CONSTITUTION:The optical fiber cable 16 with the freezing hazard preventive pipes is previously produced by arraying the freezing hazard preventive pipes 12 along the optical fiber cable 10 and bundling and integrating the cable and the pipes by means of the binders 14. Such optical fiber cable 16 with the freezing hazard preventive pipes is drawn into a pipeline 20. Namely, the wires are spirally wound while the freezing hazard preventive pipes 12 are placed vertically along the optical fiber cable 10 at the time of production, by which the integrated optical fiber cable 16 with the freezing hazard preventive pipes is produced. The optical fiber cable 16 with the freezing hazard preventive pipes is laid by an ordinary method of carrying a drum 160 wound with this optical fiber cable to a laying site and pulling the optical fiber cable 16 with the freezing hazard preventive pipes by a winch can 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cable with a freezing obstacle prevention pipe, which is housed in an underground pipe,
It concerns the laying method.

[0002]

[Prior art]

(1) Freezing obstacle prevention pipe In cold regions, as shown in Fig. 2, the optical fiber cable 1
When the temperature drops below the freezing point in a state where water 22 is accumulated in the underground buried pipeline 20 in which 0 is laid, the water freezes. When water freezes, the volume expands. The swollen ice is the void 24
Fill in. If the void portion 4 is sufficiently wide, there is no problem for the optical fiber cable, but if the void portion 24 is narrow, a problem occurs. That is, the expanded ice will be transferred to the conduit 20.
To spread out or crush the optical fiber cable 10. When the conduit 20 is made of metal, the force to spread it out is suppressed, and it acts as a force to crush the optical fiber cable 10.
By the function of this crushing force, the optical fiber cable 1
In many cases, 0 is crushed and a failure occurs. This is called an optical fiber cable freeze failure.

FIG. 3 shows a method which has been devised and widely adopted for preventing a freezing failure of an optical fiber cable. Freezing prevention pipe 1 made of hollow polyethylene pipe
2 together with the optical fiber cable 10 into the same conduit 20
It is a method of arranging them side by side. As above, water 22
Imagine a case of freezing. When the water 22 freezes and expands, the expanded hard ice first fills the narrow void portion 4. If it is still insufficient, it works as a force to crush the optical fiber cable 10 and the freeze prevention pipe 12. At this time, since the freezing obstacle prevention pipe 12 is hollow,
It is easier to crush than the optical fiber cable 10, and the freezing obstacle prevention pipe 12 is crushed first. If the anti-freezing obstacle 12 is thick enough, the volume expansion of ice can be sufficiently absorbed, so that the optical fiber cable 10 will not be obstructed.

As shown in FIG. 4, the commonly used freeze prevention pipe 12 has a structure in which a hollow pipe is crushed at a certain length and sealed. 121 is a hollow section and 123 is a seal section. Freezing obstacle prevention pipe 1
When 2 breaks and water enters, assuming that the entire length is hollow, the antifreezing function is impaired over the entire length. However, by intermittently sealing, the section where the anti-freezing prevention function is impaired is minimized, and at the same time, the restoring force of the pipe due to the internal pressure of the air when the ice melts is secured.

(2) Method of laying the freeze damage prevention pipe 12 The above freeze damage prevention pipe 12 and the optical fiber cable 1
A conventional method of laying 0 and 0 in the same pipeline 20 will be described. Simultaneous laying method As shown in FIG. 5, the drum 120 of the freezing obstacle prevention pipe 12
Is installed on the drum 100 side of the optical fiber cable 10, and the optical fiber cable 10 and the freeze prevention pipe 12
Conventionally, a method of simultaneously pulling with the winch wheel 30 is generally performed. 21 indicates a hand hole.

Post-Installing Method As an alternative method, after the optical fiber cable 10 is installed by a general method using a winch wheel 30, a freezing obstacle prevention pipe 12 is later installed in the gap between the conduit 20 and the optical fiber cable 10. It is laid by a general method using a winch wheel 30.

[0007]

[Problems to be Solved by the Invention]

(1) In the case of the simultaneous laying method It is inevitable that the optical fiber cable 10 and the freeze prevention pipe 12 are entangled as shown in FIG. When the optical fiber cable 10 and the anti-freezing obstacle prevention pipe 12 are entangled with each other, uniform tension is not applied to the optical fiber cable 10 and the anti-freezing obstacle prevention pipe 12, and the laying tension is not stable, which adversely affects the quality of the optical fiber cable 10. It may extend. In extreme cases, as shown in FIG. 7, slack may occur in the freezing obstacle prevention pipe 12 and the pipe 20 may be clogged, making it impossible to lay a cable. After the installation is completed, when a failure occurs in the optical fiber cable 10, it is necessary to pull out the optical fiber cable 10 from the conduit 20. At this time, the freeze prevention pipe 12
If the optical fiber cable 10 is entangled, it becomes very difficult to pull out the optical fiber cable 10. In the extreme case, the conduit 20 is clogged and the optical fiber cable 10 cannot be pulled out.

(2) In case of post-installation Although it is effective when there is a sufficiently large gap between the optical fiber cable 10 and the conduit 20, the optical fiber cable 1
No. 0 is laid and the antifreezing pipe 12 is laid, resulting in double labor and inefficiency. If the gap between the optical fiber cable 10 and the conduit 20 is small,
It is difficult to apply this method.

(3) Other Problems It is assumed that the optical fiber cable 10 and the freezing obstacle prevention pipe 12 are installed in a median strip of an expressway or an underground buried pipeline of a bypass zone. Generally when working on highways,
It is necessary to regulate traffic. However, traffic restrictions cause traffic congestion, so it is necessary to minimize work time. In such a case, compared with the case where only the optical fiber cable 10 is laid, the work is complicated in both the above-mentioned simultaneous laying method and the subsequent laying method, and there is a concern that the working time is significantly increased.

[0010]

Means for Solving the Problems As shown in FIGS. 1A and 1B, an optical fiber cable 10
The optical fiber cable 16 with the anti-freezing prevention pipe is previously manufactured, and the optical fiber cable 16 with the anti-freezing failure pipe is integrated in advance by arranging the anti-freezing prevention pipe 12 side by side and bundling them with the binder 14.
Is drawn into the conduit 20.

[0011]

[Operation] Optical fiber cable 10 and freeze prevention pipe 1
When 2 and 2 are bundled together by a binder 14 and integrated, the optical fiber cable 10 and the freeze damage prevention pipe 12
As shown in FIG. 6, there is no entanglement, and as shown in FIG.
It does not get stuck in 0. Since the optical fiber cable 16 with the freeze damage prevention pipe in which the optical fiber cable 10 and the freeze damage prevention pipe 12 are integrated can be handled as one long body, the laying work becomes easy.

[0012]

EXAMPLE FIG. 1A shows a case where a metal wire or the like is spirally wound as the binder 14. When manufacturing the cable,
A wire is spirally wound around the optical fiber cable 10 while the freezing obstacle prevention pipe 12 is vertically provided to form an integrated optical fiber cable 16 with the freeze obstacle preventing pipe. Then roll it up on a drum. The binder 14 is
It may be attached intermittently as shown in FIG.

A drum 160 around which an optical fiber cable 16 with a freeze prevention pipe is wound, as shown in FIG.
The optical fiber cable 16 with a freeze prevention pipe is towed by a winch wheel 30 and then installed by a usual method.

[0014]

【The invention's effect】

(1) Trouble such as clogging of the pipeline during installation can be eliminated. (2) Since the cable laying tension is stable, the quality of the optical fiber cable is stable. (3) The work time for laying can be reduced. (4) The laying work is simplified and effective in terms of safety measures. (5) When the optical fiber cable or the antifreezing pipe or both of them fail and need to be pulled out from the pipeline, they can be pulled out together. Therefore, one does not get caught on the other.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of the present invention, (a) and (b)
Shows a different type of optical fiber cable 16 with a freezing obstacle prevention pipe, and (c) shows a model of the installed state.

FIG. 2 is an explanatory view of a state in which water is infiltrated in the pipe line 20.

FIG. 3 is an explanatory view of a state in which a freeze damage prevention pipe 12 is added to the optical fiber cable 10 in a pipe line 20.

FIG. 4 is a model explanatory view of a freeze prevention pipe 12.

FIG. 5 is an explanatory diagram of an example of a conventional technique.

FIG. 6 is an explanatory view of a state in which the optical fiber cable 10 and the freeze prevention pipe 12 are intertwined, which is one of the problems in the conventional case.

FIG. 7 is an explanatory diagram showing another problem in the conventional case, that is, a state in which a slack has occurred in the freeze damage prevention pipe 12 and the pipe 12 is clogged.

[Explanation of symbols]

 10 Optical Fiber Cable 12 Freezing Obstruction Prevention Pipe 14 Binder 16 Optical Fiber Cable with Freezing Obstruction Prevention Pipe 20 Pipeline 21 Handhole 22 Water 24 Void 30 Winch Wheel 100, 120, 160 Drum

Claims (2)

[Claims] 1. An optical fiber cable with a freeze prevention pipe, wherein the freeze prevention pipes are arranged side by side on the optical fiber cable and are bundled with a binder to be integrated. 2. When the optical fiber cable and the anti-freezing prevention pipe are accommodated side by side in one conduit, the optical fiber cable and the anti-freezing prevention pipe are bundled with a binder to be integrated with the anti-freezing obstacle pipe. A method for laying an optical fiber cable with a freezing obstacle prevention pipe, which comprises manufacturing an optical fiber cable in advance and drawing it into the pipe.