JPH10104475A - Pipe for running optical fiber through - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an optical fiber unit from deteriorating owing to ultraviolet rays without spoiling internal visibility by coating an internal-layer pipe with a weatherproof coating material. SOLUTION: The pipe 3 has the internal-layer pipe 3a and the weatherproof coating material 3b which covers the internal-layer pipe 3a. The internal-layer pipe 3a is a pipe formed of transparent or translucent plastic and used by letting an optical fiber unit, consisting of the optical fiber unit 4 consisting of one or plural coated optical fibers formed by providing an optical fiber 4a with a resin coating 4b, through. As the internal-layer pipe 3a, there is a pipe formed of, for example, polyethylene, as preferable one. The coating material 3b is formed of synthetic resin which impedes the transmission of light, specially, ultraviolet rays. As the coating material 3b, polyethylene containing, for example, carbon black by several % is preferable. Here, the coating material 3b is provided for the internal-layer pipe 3a in a peelable state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber transmission pipe for transmitting an optical fiber.

[0002]

2. Description of the Related Art In an optical fiber communication line network, when a station is connected to a subscriber (user), a collective drop cable is required. As this collective drop cable, for example, there is a form in which a plurality of optical fiber transmission pipes made of transparent or translucent plastic are twisted around a tension member serving as a core.

When an optical fiber is laid to realize fiber-to-the-home using this collective drop cable, the collective drop cable is first wired. Then, the optical fiber unit is pressure-fed to the hollow portion of the optical fiber transmission pipe of the collective drop cable by compressed air (air blown method). Thereafter, a predetermined optical fiber transmission pipe is separated from the collective drop cable and wired to a predetermined subscriber. Therefore, the communication terminal of the predetermined subscriber is connected to the optical fiber for the predetermined subscriber. In this way, the station and the subscriber are connected.

[0004] The ordinary collective drop cable is provided with a sheath on the outermost layer, while the collective drop cable used for distributing individual optical fiber pipes to each subscriber separates the optical fiber pipes. A structure without a sheath may be considered for ease.

[0005]

The optical fiber transmission pipe is transparent or translucent so that the presence or absence of the transmitted optical fiber can be easily identified. Therefore, in the case of an optical fiber transmission pipe laid outdoors,
The ultraviolet light transmitted through the pipe is irradiated on the optical fiber unit in the pipe, and the resin coating of the optical fiber unit is deteriorated by the ultraviolet light, resulting in a problem of shortening the life.

[0006] In order to avoid such inconveniences, for example, plastics constituting an optical fiber transmission pipe include, for example,
Ultraviolet rays are blocked by adding carbon black to make it opaque. However, if the transmission pipe is made opaque, the internal visibility is impaired, and the thinness of the transmission pipe makes it impossible to check the presence or absence of the optical fiber unit, which lowers the work efficiency when laying the optical fiber. become.

The present invention solves the above-mentioned problems in the optical fiber transmission pipe of the collective drop cable, and can prevent deterioration of the optical fiber unit due to ultraviolet rays without impairing the internal visibility. The purpose is to provide.

[0008]

In order to achieve the above object, an optical fiber transmission pipe according to the present invention comprises: an inner pipe made of a transparent or translucent plastic; and a weather-resistant covering material for covering the inner pipe. It was configured to be equipped. Further, in the optical fiber transmission pipe of the present invention, it is preferable that a tear string is interposed between the inner layer pipe and the weatherproof covering material.

Further, in the optical fiber transmission pipe of the present invention, it is preferable that the tear string is made of a tensile strength material. In this specification, the weather-resistant coating material refers to a coating material having a property of preventing transmission of light, particularly ultraviolet light.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical fiber transmission pipe according to the present invention will be described with reference to the accompanying drawings. FIG.
1 is a cross-sectional view of a collective drop cable provided with an optical fiber transmission pipe of the present invention.
A tension member 2 serving as a core and a plurality of optical fiber transmission pipes (hereinafter, referred to as pipes) 3 twisted around the tension member 2 are provided.

The tension member 2 is usually formed by covering a wire 2a made of a tensile strength material with a synthetic resin 2b.
Examples of the wire 2a include a metal wire such as a steel wire, an inorganic material fiber such as a glass fiber, a plastic fiber such as Teflon, nylon, polyester, and polypropylene. These fibers are usually twisted to increase the tensile strength.

As the synthetic resin 2b, for example, a resin such as polyethylene is used. As shown in FIG. 2, the pipe 3 includes an inner pipe 3a and a weather-resistant covering material (hereinafter referred to as a covering material) 3b that covers the inner pipe 3a. The inner layer pipe 3a is a pipe made of a transparent or translucent plastic, and is used by passing an optical fiber unit 4 composed of one or more optical fiber cores obtained by applying a resin coating 4b to an optical fiber 4a. . As the inner layer pipe 3a, for example, a pipe made of polyethylene or the like is preferable. Here, in the present invention, “transparent or translucent” means having a light transmittance enough to make the inside visible.

The coating material 3b is a synthetic resin having a property of preventing transmission of light, especially ultraviolet light. Suitable examples of the coating material 3b include polyethylene containing about several percent of carbon black. Here, the covering material 3b covers the inner pipe 3a in a peelable state. That is, the covering material 3b is in a state where it can be easily peeled off later.

Next, a procedure for connecting a station and a subscriber by an optical fiber using the collective drop cable 1 having the optical fiber transmission pipe of the present invention will be described below.
First, a collective drop cable 1 in which a plurality of pipes 3 are twisted and arranged around a tension member 2 is wired. Then, when an optical fiber is required due to an increase in the number of subscribers or the like, the optical fiber unit 4 having at least the required number of optical fiber cores is pressure-fed to the hollow portion of one of the pipes 3 by the pressure of compressed air. , Pipe 3
A predetermined optical fiber unit 4 is passed through the inside. FIG.
In order to simplify the drawing, the case where the optical fiber unit 4 has one optical fiber core is shown.

Next, the pipe 3 is appropriately separated from the collective drop cable 1 provided with the pipe 3 through which the optical fiber unit 4 has been passed, and wired near the subscriber. At this time, the inside of the pipe 3 is invisible due to the coating material 3b. In this case, the worker peels off the coating material 3b with a knife or the like, and puts the optical fiber unit 4
After confirming that is transmitted, the pipe 3 is wired to the subscriber. After checking the presence or absence of the optical fiber unit 4, if the portion where the coating material 3b has been peeled off is repaired with an adhesive tape or the like, the weather resistance of the pipe 3 can be maintained.

Then, each optical fiber unit 4 is connected to a communication terminal on the subscriber side. As described above, since the pipe 3 of the present invention includes the coating material 3b on the outermost layer, transmission of light, particularly ultraviolet light, is prevented. For this reason, compared with the case where the optical fiber unit is passed through the conventional transparent pipe, the resin coating 4b of the optical fiber unit 4 by the ultraviolet rays is used.
Of the optical fiber unit can be extended, and the life of the optical fiber unit can be extended. Moreover, the coating material 3b is made of the inner pipe 3a.
, The presence or absence of the optical fiber unit 4 in the pipe 3 can be easily confirmed.

Here, as another embodiment of the present invention, a pipe 3 in which the coating material 3b has improved releasability will be described below. In addition, about the same component as the said embodiment,
The same reference numerals are given and the detailed description is omitted. Pipe 3
As shown in FIG. 3, an inner pipe 3a, a coating material 3b,
A tear string 3c is provided between the inner pipe 3a and the covering material 3b.

The tear string 3c is a string disposed between the inner pipe 3a and the covering material 3b along the longitudinal direction of the inner pipe 3a. The end of the tear string 3c protrudes from the end of the pipe 3 by a predetermined length.
When the coating material 3b is peeled off from the pipe 3, first, the end of the tear string 3c is pulled in the direction of arrow A in FIG. Then, the covering material 3b tears along the tear string 3c, and the covering material 3b can be easily peeled off from the tear. Thus, the coating material 3b is peeled off, and the pipe 3
The presence or absence of the optical fiber unit 4 is checked.

Here, if a tensile strength material such as an aromatic polyamide fiber is used as the tear string 3c, the aromatic polyamide fiber not only functions as a tear string but also when wiring the pipe 3 to each subscriber. Furthermore, it is preferable because it also functions as a tension member for preventing the pipe 3 from expanding.

[0020]

As is apparent from the above description, since the optical fiber transmission pipe of the present invention is provided with the weather-resistant coating material, the amount of transmitted ultraviolet light can be minimized.
Therefore, even if the wiring is outdoors, in the optical fiber unit in the optical fiber transmission pipe, deterioration of the resin coating due to ultraviolet rays is suppressed as much as possible.
Further, deterioration of the optical fiber transmission pipe itself is also suppressed.

Further, since the coating material used in the present invention can be easily peeled off, the inside of the pipe can be easily visually recognized. For this reason, it can be easily confirmed whether or not the optical fiber unit is sent inside. Furthermore,
The optical fiber transmission pipe according to claim 2 of the present invention is:
Since the tear-resistant cord is provided, the weather-resistant covering can be easily peeled off by pulling the cord, and the covering can be easily removed.

Furthermore, in the optical fiber transmission pipe according to the third aspect of the present invention, since a tensile strength material is used as the tear string, the weather-resistant coating material can be easily peeled off, and the coating material can be easily peeled off. The portion of the tensile strength material not used for removing the pipe functions as a tension member for preventing the pipe from expanding when wiring the pipe to each subscriber. For this reason, when wiring the pipe to each subscriber, there is no need to prepare a separate support line for the pipe, and the laying operation excellent in economy can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a collective drop cable.

FIG. 2 is a sectional view of an optical fiber transmission pipe according to the present invention.

FIG. 3 is a cross-sectional view of another embodiment of the optical fiber transmission pipe according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Collective drop cable 2 Tension member 2a Wire 2b Synthetic resin 3 Optical fiber transmission pipe 3a Inner layer pipe 3b Weatherproof coating material 3c Tear string 4 Optical fiber unit 4a Optical fiber 4b Resin coating

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Kazuo Hokari 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. An optical fiber transmission pipe, comprising: an inner pipe made of transparent or translucent plastic; and a weather-resistant covering material for covering the inner pipe. 2. The optical fiber transmission pipe according to claim 1, wherein a tear string is interposed between the inner layer pipe and the weatherproof covering material. 3. The optical fiber transmission pipe according to claim 2, wherein the tear string is made of a tensile strength material.