WO2024214179A1 - Optical fiber cable and method for laying optical fiber cable - Google Patents

Abstract

The purpose of the present disclosure is to provide: an optical fiber cable that can be prevented from protruding from a ditch in which the optical fiber cable has been laid; and a method for laying the optical fiber cable.　This optical fiber cable (1) comprises an optical fiber core wire (11), a sheath (12) that accommodates the optical fiber core wire, and an expanding part (13) that is provided to the outside of the sheath and expands upon absorbing liquid.

Description

Optical fiber cable and method for laying optical fiber cable

This disclosure relates to an optical fiber cable and a method for laying an optical fiber cable.

Patent Document 1 and Non-Patent Document 1 disclose technology for laying optical fiber cables in grooves formed in road surfaces or mats.

Japanese Unexamined Patent Publication No. 63-55204

Akira Sakurai, 4 others, “Feasibility study of optical fiber cables for on-road surface wiring”, 70TH ANNUAL IWCS CABLE & CONNECTIVITY INDUSTRY FORUM, IWCS, OCTOBER 4-8, 2021

However, because optical fiber cables have a tendency to twist and bend, they can protrude from the trench between the time the cable is laid and the time the repair material is filled into the trench, creating a risk of the installer tripping over it and endangering their safety. In addition, the optical fiber cable that protruded from the trench had to be returned to the trench, which increased construction time.

This disclosure has been made in consideration of the above circumstances, and the purpose of this disclosure is to provide an optical fiber cable and an optical fiber cable installation method that can prevent the optical fiber cable laid in a trench from protruding from the trench.

The optical fiber cable of one embodiment of the present disclosure comprises an optical fiber core, an outer jacket that houses the optical fiber core, and an expansion section that is provided on the outside of the jacket and expands upon absorbing liquid.

In one embodiment of the present disclosure, a method for laying an optical fiber cable includes laying an optical fiber cable having an optical fiber core, an outer jacket that houses the optical fiber core, and an expansion section that is provided on the outside of the jacket and expands by absorbing liquid, in a groove, and pouring liquid into the groove.

In one embodiment of the present disclosure, a method for laying an optical fiber cable includes pouring liquid into a groove, and laying an optical fiber cable in the groove, the optical fiber cable including an optical fiber core, an outer jacket that houses the optical fiber core, and an expansion section that is provided on the outside of the jacket and expands by absorbing the liquid.

The present disclosure provides an optical fiber cable and an optical fiber cable installation method that can prevent the optical fiber cable laid in a trench from protruding from the trench.

FIG. 1 is a cross-sectional view of an optical fiber cable. FIG. 2 is a diagram showing an image of a method for producing an optical fiber cable. FIG. 3 is a diagram showing an image of a method for laying an optical fiber cable. FIG. 4 is a side view of the optical fiber cable. FIG. 5 is a side view of the optical fiber cable. FIG. 6 is a diagram showing a cross section of an optical fiber cable. FIG. 7 is a diagram showing a cross section of an optical fiber cable.

Below, an embodiment of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same parts are given the same reference numerals and the description will be omitted.

[Summary of the Disclosure]
The present disclosure provides a method for covering an optical fiber cable with an expansion layer made of a material that expands when it absorbs water. The present disclosure also provides a method for laying an optical fiber cable covered with an expansion layer in a groove formed in a road surface or a mat, and then injecting water into the groove.

This allows the expansion layer to expand until it reaches the width of the groove, generating friction between the expansion layer and the groove, preventing the optical fiber cable from jumping out of the groove from the time the optical fiber cable is laid until the repair material is filled into the groove. As a result, the optical fiber cable can be prevented from protruding from the groove, improving construction safety. It also reduces the construction work required to return the optical fiber cable that has protruded from the groove back into the groove.

[Configuration of optical fiber cable]
FIG. 1 is a diagram showing a cross section of an optical fiber cable according to the present embodiment.

The optical fiber cable 1 comprises a plurality of optical fiber cores 11, an outer jacket 12 that houses the plurality of optical fiber cores 11, and an expansion section 13 provided on the outside of the outer jacket 12.

The multiple optical fiber cores 11 and the jacket 12 are, for example, an existing optical fiber cable in which multiple optical fiber cores are bundled together and covered with a jacket.

The expansion section 13 is an expansion layer that is superimposed on the outer layer of the outer cover 12 and is made of a material that expands by absorbing liquid supplied from the outside. For example, the expansion section 13 is a water-expandable nonwoven fabric that expands by absorbing water.

[How to make an optical fiber cable]
FIG. 2 is a diagram showing an image of a method for producing the optical fiber cable 1. As shown in FIG.

The installer creates the optical fiber cable 1 of this embodiment by wrapping the tape-like expansion portion 13 around the entire outer surface of the jacket 12 that constitutes the existing optical fiber cable 100. The task of wrapping the expansion portion 13 can be easily performed at the construction site. The installer may attach the expansion portion 13 to the outer surface of the jacket 12 with adhesive.

[Method of laying optical fiber cable]
FIG. 3 is a diagram showing an image of a method for laying the optical fiber cable 1. As shown in FIG.

The installer lays the optical fiber cable 1 with the expansion section 13 inside a trench 3 formed in the road surface 2. The installer then pours water into the trench 3 using a watering can 4. The expansion section 13 then absorbs the water poured into the trench 3 and grows larger.

As the expansion section 13 expands and its volume increases, the outer diameter W of the optical fiber cable 1 gradually increases. The outer diameter W of the optical fiber cable 1 was less than the width of the groove 3 before the expansion section 13 expanded, but becomes equal to or greater than the width of the groove 3 after the expansion section 13 expands. When the outer diameter W of the optical fiber cable 1 increases to reach the width of the groove 3, a frictional force is generated between the expansion section 13 and the side wall surface of the groove 3 (part P shown in Figure 3). This frictional force prevents the optical fiber cable 1 from jumping out of the groove 3.

In addition, after pouring water into the groove 3, the optical fiber cable 1 having the expansion section 13 may be laid inside the groove 3. Even in this case, the expansion section 13 will absorb the water and become larger, so the same effect can be obtained.

[Example 1 of expanding portion formation]
The expansion portion 13 may be formed on a portion of the outer surface of the outer cover 12 .

For example, as shown in FIG. 4, the expansion portion 13 is formed by periodically wrapping or attaching the expansion portion 13, which has a width smaller than the length of the outer sheath 12 in the extension direction, perpendicular to the extension direction of the outer sheath 12 (horizontal direction in FIG. 4).

For example, as shown in FIG. 5, it is formed by attaching multiple expansion sections 13 with a width smaller than the circumferential length of the outer sheath 12 in parallel in the extension direction of the outer sheath 12.

[Example 2 of expanding portion formation]
The inflatable portion 13 may be wrapped around the outer cover 12 multiple times.

For example, as shown in FIG. 6, the tape-like expansion section 13 is formed by partially overlapping and spirally wrapping or attaching it around the entire circumference of the outer sheath 12. The thickness of the expansion section 13 can be adjusted by the number of times it is wrapped around.

For example, as shown in FIG. 7, it is formed by stacking and attaching multiple expansion sections 13, each with a width smaller than the circumferential length of the outer jacket 12, to a portion of the outer jacket 12 in the circumferential direction (particularly the outer surface portion facing the side wall surface of the groove 3). The thickness of the expansion section 13 can be adjusted by the number of overlapping sheets.

[Example 3 of expanding portion formation]
Alternatively, the expansion portion may be formed in a concentrated manner in a portion having a tendency to twist.

[effect]
According to this embodiment, the optical fiber cable 1 includes the expansion portion 13, and in the groove in which the optical fiber cable 1 is laid, the expansion portion 13 expands by absorbing water until it reaches the width of the groove, and a frictional force is generated between the expansion portion 13 and the groove, so that the optical fiber cable 1 can be prevented from jumping out of the groove. As a result, the optical fiber cable can be prevented from protruding from the groove, and installation safety can be improved. In addition, the installation work for returning the optical fiber cable protruding from the groove back into the groove can be reduced.

Furthermore, customization of the optical fiber cable itself is not necessary to achieve these objectives, and conventional optical fiber cables can be used as is. Furthermore, the expansion section is easy to handle, and the thickness of the expansion layer can be flexibly adjusted to match the width of the trench at the construction site. In particular, by forming the expansion section as part of the outer surface of the outer jacket, the amount of expansion section used can be reduced.

Reference Signs List 1 Optical fiber cable 2 Road surface 3 Groove 4 Watering can 11 Optical fiber core 12 Jacket 13 Expanded portion 100 Existing optical fiber cable

Claims (5)

An optical fiber core;
an outer jacket for housing the optical fiber;
an expansion portion provided on the outside of the outer cover and expanding by absorbing liquid;
1. A fiber optic cable comprising: The outer diameter of the optical fiber cable is
2. The optical fiber cable according to claim 1, wherein the width of the expansion portion before expansion is less than the width of a groove in which the optical fiber cable is laid, and the width of the expansion portion after expansion is equal to or greater than the width of the groove. The expansion portion is
The optical fiber cable according to claim 1 , wherein the outer jacket is provided on all or a part of its outer surface. A method for laying an optical fiber cable, comprising:
An optical fiber cable including an optical fiber core, an outer jacket for housing the optical fiber core, and an expansion part provided on the outside of the outer jacket and expanding by absorbing liquid is laid in a trench;
placing a liquid in said groove;
How to lay optical fiber cables. A method for laying an optical fiber cable, comprising:
Put liquid into the groove
an optical fiber cable including an optical fiber core, an outer jacket for accommodating the optical fiber core, and an expansion part provided on the outside of the outer jacket and expanding by absorbing liquid is laid in the trench;
How to lay optical fiber cables.

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