JP2002250849A - Optical fiber cable inserted into sewer pipe in operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate flow obstruction in sewer even though an optical fiber cable is inserted into a sewer pipe in operation by applying a smoothing process to the external periphery of the cable. SOLUTION: The external periphery of an optical fiber cable, which is to be inserted into a sewer pipe in operation, is covered by a smoothing material so that dirt and solid bodies hardly adhere to the cable.

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 routed through an existing sewer pipe.

[0002]

2. Description of the Related Art A high-capacity optical fiber is the most suitable as an information transmission medium for today's highly developed information society. Recently, a sewer network has become widespread, and a method using this sewer pipe has been proposed. However, aside from newly installed sewer pipes, it is quite troublesome to pass optical fiber cables through existing sewer pipes.

[0003]

This is because the optical fiber cable is not immersed in the sewage flowing in the sewer pipe. For this purpose, a locking structure for supporting or suspending the optical fiber cable in the sewer pipe is used. This is because an attempt is made to provide The present invention allows the optical fiber cable to be easily immersed in the sewage, but anyway, on the other hand, by taking measures to minimize the adverse effects caused by immersion, it is possible to easily conduct the wiring, and in addition, the cost is greatly increased It is intended to reduce it.

[0004]

SUMMARY OF THE INVENTION In view of the above, the present invention relates to an optical fiber cable according to the present invention, wherein the outer periphery of the optical fiber cable is drained. Provided is an optical fiber cable which is passed through an existing sewer pipe, which is coated with a smooth material to which dirt and solid matter hardly adhere.

According to the present invention, since the optical fiber cable is drawn through the existing sewer pipe in a flowing manner, that is, without any locking, the cable often crawls on the bottom of the sewer pipe by its own weight. It is immersed in sewage flowing through a sewer pipe. On the other hand, the wiring work is easy and the cost of the wiring is greatly reduced. By the way, the biggest adverse effect caused by immersing the optical fiber cable in the sewage flowing in the sewer pipe is that it is expected that solid matter such as dirt and paper will adhere to this and cause a sewage flow obstruction. is there.

Therefore, according to the present invention, the outer periphery of the optical fiber cable is covered with a smooth material to which dirt and solid matter in the sewage hardly adhere. This makes it difficult for the dirt and solids to adhere, and even if they do, it is expected that they will be separated by the flow of sewage. As the smoothing material, a fluorine resin or a silicon resin described in claim 2 can be considered, and among them, the fluorine resin is most preferable. These have a low coefficient of friction and have a smoothing action that does not allow substances to adhere, so it is difficult for dirt and solids to adhere, and even if they adhere,
Peeled off by slight external force.

[0007] Sewage contains corrosive components (gas) such as ammonia and flowing hydrogen, and there is a problem that these may corrode the optical fiber cable. Immersion and non-immersion do not matter much. However, it is considered that the above-mentioned substances are chemically stable and resistant to corrosion.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a two-core type optical fiber cable passed through a sewer pipe. As is well known, an optical fiber cable C has a tension resistant material called a tension member 1 as a core and a refractive index around the core. Optical fiber 2 and buffer material 3 made of quartz glass or resin
Are covered with a clad 4 having a low refractive index, and the outer periphery thereof is covered with a sheath 5 of PVC or LAP.

In the present invention, the outer periphery of the cable C is covered with the smoothing material 6. The smoothing material 6 may be covered from above the sheath 5 or may be covered instead of the sheath 5. . The method of coating may be a conventional method. Although not shown, a straight member such as a steel wire may be added to the cable C. In this case, the cable is straightened and hard to bend, the flow resistance of the sewage is reduced, and the object is hard to adhere.

As the smoothing material 6, a fluororesin or a silicone resin is suitable, and among them, a fluororesin is most suitable.
Fluororesin is a general term for synthetic resins containing fluorine,
There are various types including polytetrafluoroethylene having a trade name of “Teflon”, and any of them may be used.
There are various types of silicone resin (silicon resin), and any of them may be used.

FIG. 2 is a cross-sectional view of the case where the cable C is passed through the sewer pipe 7. In the present invention, the cable C is drawn into the sewer pipe 7, that is, locking or engaging is performed. The train runs without doing it. Although there is no particular limitation on the method of passing the wires, since they are of the flow-through type, they are easy and cost-effective in any case. According to the above line, cable C
Sinks at the bottom of the sewer pipe 7 by its own weight and is usually immersed in the sewage W.

However, since the smoothing material 6 made of a fluororesin or a silicone resin has a low friction coefficient and has a smoothing action to which a substance is hardly adhered, the cable C coated with the smoothing material 6 was immersed in the sewage W as described above. As well as waste contained in sewage W,
It is considered that solids such as paper are prevented from adhering and no flow obstruction is caused. This means that the sewage W is hardly stained.

However, even if it adheres, since the sewage W repeatedly flows down intermittently, it is expected that the sewage W will be washed away by the next downflow and will not adhere much. In fact, according to the results of a test performed by the present inventor for about one month, almost no adhesion was observed, and even a slight adhesion was able to be peeled off by gently wiping. This means that sewage W
It is supposed that adhesion and peeling are repeated each time stagnation and flow-down occur, and as a result, adhesion that causes flow-down failure does not occur.

[0014]

As described above, according to the present invention, a low-cost and easy-to-construct optical fiber cable is drawn down into an existing sewer pipe so that the cable is immersed in the sewage. Since it is covered with a difficult smoothing material, it does not adhere dirt and solid matter in sewage. Even if they adhere, they do not separate due to the flow of sewage, and do not cause a flow obstruction as a result.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an optical fiber cable used in the present invention.

FIG. 2 is a cross-sectional view showing an example of a state where the optical fiber cable according to the present invention is connected to a sewer pipe.

[Explanation of symbols]

 C Optical fiber cable W Sewage 2 Smooth material 7 Sewage pipe

Claims (2)

[Claims] Claims: 1. An optical fiber cable, which is drawn through an existing sewer pipe in a downflow manner, wherein an outer periphery of the optical fiber cable is covered with a smooth material to which dirt and solid matter in the sewer hardly adhere. Optical fiber cable that runs through the sewer. 2. The optical fiber cable according to claim 1, wherein the smoothing material is a fluororesin or a silicone resin.