JPH0232711A - Cable laying/collecting method - Google Patents

Abstract

PURPOSE:To prevent degradation of the carrying speed of an optical cable due to residual matter by supplying gas into a conduit and carrying the cable toward the downstream thereby removing residual matter from the conduit. CONSTITUTION:Collecting pipes 17 are laid while being coupled through joints 20, 21 arranged with a predetermined interval in an underground pit 19. When an optical fiber 11 is laid while being fed forcedly through gas, dry gas is pressure fed for a predetermined time into a pipe 15 to be inserted with the cable 11 in order to remove residual water or dust from the pipe. In other words, the joint pipe 27 of a cable force feeder 26 is coupled to the end of an extension pipe 22 at position A and gas is pressure fed into the extension pipes 22, 24 and the cable pipe in the collecting pipe 17, then residual water in each pipe is discharged together with dust from the end section of the extension pipe 24 at a position B while being evaporated partially.

Description

[Detailed Description of the Invention] <Public Expenses for Industrial Use> The present invention allows gas to flow into a pipe, and the cable is conveyed smoothly and quickly by this flow 1, and the cable is laid in the pipe or recovered from the pipe. The present invention relates to a cable installation and recovery method, and is particularly suitable for application to the installation and recovery of optical fiber cables.

<Conventional technology> In recent years, with the development of optical communication technology using optical fibers,
The forms of its use have become extremely diversified, and various methods are being developed and introduced for the installation of optical fiber clamps.

For example, one way to do this is to lay a cable conduit consisting of a collection of thin pipe-like ducts and thin tubes in advance in sections where it is expected that it will be needed in the future, and then when the cable line becomes necessary at a later date. There is a method of inserting an optical fiber cable into a cable pipe. The advantage of this method is that the initial investment can be reduced by avoiding the advance installation of optical fibers that are not used for the time being and by installing optical fiber lines as needed. The above-mentioned method is particularly effective when installing optical cables inside buildings, from the viewpoint of securing installation space and reducing construction costs.
It is also effective when attempting to construct an optical communication network using gas pipes, water/sewage pipes, and various electrical wiring.

By the way, as a method for pushing an optical fiber cable through a pre-installed cable pipe, there is a method described in Japanese Patent Application Laid-Open No. 59-1.
There is a "method and apparatus for laying optical fiber cable" proposed in the specification of Japanese Patent No. 04607.

The method disclosed in Japanese Patent Application Laid-Open No. 59-104607 is a method in which a gaseous medium flows in the direction of the traveling path of an optical fiber cable to be inserted into a cable pipe at a speed higher than the traveling speed of the optical fiber cable. It creates a flow and uses that pressure to push the optical fiber cable through.

<Problems to be Solved by the Invention> When laying a cable pipe for storing optical fiber cables, there is a risk that water, chips, etc. may remain in the cable pipe during the work, and the cable pipe may remain in the cable pipe even after installation. There is a possibility that moisture, etc. may infiltrate from the connection part of the pipe and remain inside the pipe. For this reason, when gas is forced into the cable pipe that has been laid in advance and the optical fiber cable is sent out and pushed through the cable pipe by the flow of gas, water and foreign substances remaining in the pipe are removed from the cable pipe. As a result of adsorption to the optical fiber or optical fiber cable, the frictional resistance of the optical fiber cable against the cable tube increases, resulting in a problem in that the delivery speed of the optical fiber cable is significantly reduced. A similar problem has also been found when an optical fiber cable that has been pushed through a cable pipe is recovered by pumping gas into the cable pipe and using the gas flow. Furthermore, in order to solve the above-mentioned problems, various connectors have been devised that completely seal the cable pipe connections, but these types of connectors are generally large and expensive, and are difficult to install. This created a gap that made the process extremely complicated.

Means for Solving the Problems and Their Effects> The first method of laying and recovering a cable according to the present invention is to lay the cable in the pipe by flowing gas into the pipe and transporting the cable in the downstream direction by this flow. Alternatively, when the cable is recovered from inside the pipe, as a pre-process, gas is caused to flow through the pipe to eliminate any residue in the pipe that becomes an obstacle to the conveyance of the cable.

In addition, in the second method of laying and recovering a cable according to the present invention, when the cable is laid in the pipe or collected from the pipe, the gas is flowed into the pipe and the cable is conveyed in the downstream direction by this flow. The process is characterized in that a liquid is first poured into the pipe, and then a gas is further flowed to dry the inside of the pipe and remove any residue in the pipe that would be an obstacle to the conveyance of the cable.

Embodiment An embodiment in which the cable installation and recovery method according to the present invention is applied to the installation and recovery of an optical fiber cable in an underground pit will be described in detail below with reference to the drawings. As shown in FIG. 1, which is a cross-sectional view of an example of an optical fiber cable to be laid, a reinforcing wire 12 made of metal, synthetic resin fiber, etc. passes through the center of the optical fiber cable 11. A plurality of optical fibers 13 are arranged spirally surrounding the outer periphery of the reinforcing wire 12 along the reinforcing cotton 12, and these optical fibers 13 are made of synthetic resin or the like to protect the optical fibers 13. It is covered with a protective layer 14 made of. The optical fiber cable 11 has been conceived and realized in various configurations such as single-core cotton, not limited to the example mentioned above.
In the present invention, since the optical fiber cable 11 is conveyed under pressure by the force of pumped gas, it is necessary to make it as light and flexible as possible. Therefore, also
The configuration of the optical fiber cable 11 used in the present invention is not particularly limited as long as the optical fiber cable 11 is lightweight, flexible, and suitable for pressure feeding with gas or the like. This optical fiber cable 11 is installed by being inserted into a cable pressure feeding device made of synthetic resin or the like that has been installed in advance in the required section, but in this embodiment, as shown in No. 28, a plurality of cable tubes 15 are further bundled. An example will be taken in which the optical fiber cable 11 is installed in the cable pipe 15 in the collecting pipe 17 after these are installed in a necessary section as a mating pipe 17 housed in a flexible pipe 16.

In addition, as a plurality of cable pipes 15 are combined to form a joint pipe 17, the outer circumference of the cable v:15 is made such that the cable pipe 15 itself has sufficient flexibility and the hollow part of the cable pipe 15 is not crushed by bending. An annular groove 18 is formed along the outer periphery of the cable pipe 15, but the cable pipe 15 can be simply twisted and housed in the pipe 16 to provide flexibility.

In this embodiment, as shown in FIG. 3, the above-mentioned mating pipes 17 are laid in a bit 19 installed in the soil and connected by connectors 20 and 21 installed at regular intervals.

By inserting and laying the optical fiber cables 11 in each of the plurality of cable pipes 15 housed in the collecting pipe 17 as needed, it is possible to eliminate unnecessary light from the beginning for future use, that is, at the time of installation. Preliminary laying of the fiber cable 11 is avoided. Therefore, the required number of optical fiber cables 11 are first laid in the cable management system IS, and one example of a method and apparatus for doing this is to flow gas into the cable pipe 15 and use the flow of this gas. The optical fiber cable 11 is conveyed to the cable tube 15
There was already a plan to lay cables inside the JP-A-59-10.
It is reported in detail in 4607. When this installation method is applied to this embodiment, the results are generally as follows. That is, the cable tube 15 to which the optical fiber cable 11 is to be laid is cut and taken out from the connector 20 (on the left side in the figure) of the mating tube 17 laid in the bit 19, and the cable tube 15 is inserted into the cable tube 15.
Airtightly connect one end of the extension pipe 22 to the ground through the manhole 23 for a few seconds and connect the other end of the extension pipe 22 to the required location A.
(In addition, from the connector 21 provided on the right side of the mating tube 17 in the figure, the cable w1 is inserted into the extension tube 21.
Cut 5 and take it out, and add the extension of cable pipe 15% to this.
One end of the extension IIt24 is connected airtightly to the ground through the manhole 25, and the other end of the extension IIt24 is guided to the required position B.In this way, the cable w15 is connected to the extension pipe 22.2.
4 communicates from position A to position B. Thereafter, the other end of the extension tube 22 is hermetically connected to a connecting tube 27 protruding from a cable pumping device 26 for pumping the optical fiber cable 11 into the cable pipe 15.

The connecting pipe 27 is further integrally and airtightly connected to a pumping head 28, shown in FIG. 4, provided in the cable pumping device 26. A flow path 29 is formed in the pressure-feeding head 28 and communicates with the connecting pipe 27 and through which the optical fiber cable 11 is inserted, and this flow 29 linearly passes through the pressure-feeding head 28 . Furthermore, in the middle of the flow @ 29, a pair of driven pinch rollers 30 are provided which pinch the optical fiber cable 11 inserted into the flow path 29 and feed it into the cable pipe 15.
is provided. Also, in the flow ji 129 on the left side in the figure with respect to the drive pinch roller 30, the optical fiber cable 11
One end of an introduction path 31 for forcefully feeding gas into the flow path 29 at a speed faster than the sending speed of the optical fiber cable 11 is communicated along the sending direction. Furthermore, the other end of the introduction 1131 is in communication with a compressor (not shown) which is a supply source of pressurized gas and the like provided in the cable pressure feeding device 26. Therefore, in order to prevent gas from leaking from the portion 32 where the drive pinch roller 30 pinches the optical fiber cable 11 to the flow path 33 on the right side in FIG. It has a relatively large diameter, and a rubber glue seal 34 or the like is provided at its end. In order to force-feed the optical fiber cable 11 to the cable pressure-feeding device using the cable pressure-feeding device described above, the optical fiber cable 11 is inserted into the flow path 33 in the pressure-feeding head 28 and the drive pinch roller 3
While rotating the optical fiber cable 11, the optical fiber cable 11 is inserted and sent out. At the same time, a compressor (not shown) is operated to forcefully feed gas having a velocity higher than the delivery velocity of the optical fiber cable 11 through the introduction pipe 31 into the stream $29.

As a result, the optical fiber cable 11 is free from the viscous resistance force generated between the optical fiber cable 11 and the gas flow.
Due to the pressure difference that occurs in the pipe in which the material is transported, the material is pushed downstream along with the flow and is transported. Therefore, the optical fiber cable 11 is transported from position A, through extension pipe 22, through cable pipe 15 in collection w17, into extension pipe 24, and finally to position B, completing the installation work.

By the way, as described above, after the optical fiber cables 11 are installed in some of the plurality of cable pipes 15 bundled in the collecting pipe 17, a new need arises and some of the remaining cable pipes 15 are Honestly, fiber optic cable 1 again
1 from position A to position B, the installation work described above may be repeated in the same manner. On the other hand, the optical fiber cable 1 that has already been laid inside the cable pipe 15
1 from the cable pipe 15, gas is pumped into the cable pipe 15 in the same way as in the above-mentioned installation work, so that the optical fiber cable 11 is removed together with the gas.
is conveyed and pulled out from the cable pipe 15 and collected. However, as the cable pipe 15 through which the optical fiber cable 11 is to be inserted and transported during such installation and recovery work has already been installed in the bit 19 installed in the ground for a certain period of time, the connecting tool 20 etc. There is a possibility that water, dust, etc. may have entered. If water, dust, etc. enter into the cable pipe 15, these water, dust, etc. will adhere to the surface of the optical fiber cable 11 that is transported with the gas, and the viscous resistance between it and the cable pipe 15 will significantly increase. This may even lead to a situation where the transport speed of the optical fiber cable 11 is reduced and transport becomes impossible. Therefore, in the present invention, as a pre-process of the gas pressure-feeding installation work of the optical fiber cable 11 described above, in order to remove water, dust, etc. remaining in the cable pipe 15 through which the optical fiber cable 11 is pushed, A dry gas is pumped for a certain period of time. That is, A
The connecting pipe 27 of the cable pressure feeding device 26 is connected to the end of the extension pipe 22 in the position, and a compressor (not shown) is operated to forcefully transport dry gas into the extension pipes 22, 24 and the cable pipe in the joint w17. Part of the water remaining in the pipe is evaporated and discharged from the end of the extension pipe 24 at position B along with dust. Also, dry gas is pumped. Therefore, for example, a special compressor equipped with a mechanism capable of efficiently heating or dehumidifying the gas to be pumped may be used without using the cable pumping device 26. However, if the inside of the cable pipe 15 is heavily contaminated and relatively heavy foreign matter remains, there is a possibility that the above-mentioned pressure-feeding of dry gas may not be sufficient to remove the foreign matter. Therefore, in the present invention, as a pre-process of the installation work of the optical fiber cable 11, water or a liquid having a cleaning action is pumped into the cable pipe 15 through which the optical fiber cable 11 is pushed to remove the foreign matter. Thereafter, the inside of the cable pipe 15 is dried by pumping dry gas to remove the liquid and the foreign matter. That is, first, a pump or the like capable of pumping liquid is connected to the end of the extension tube 22 at position A, and the liquid is extended to the IW 22.
, 24, and into the cable pipe 15 in the collecting pipe 17, and the foreign matter and the like are discharged together with the liquid from the end of the extension pipe 24 at position B. After that, a compressor or the like capable of pumping gas is installed in place of the pump, and the dried gas is pumped to the extension pipes 22, 24 and the cable pumping device in the collecting pipe 17, and the liquid and foreign matter are removed from the extension pipe at position B. The water is discharged from the 24 ends and the inside of each pipe is dried. Furthermore, as described above, instead of pressurizing the fluid into the cable pipe 15 using a pump or compressor, the fluid can be sucked using a vacuum gimp or the like.
Of course, the above-mentioned fluid may also be allowed to flow through the tube.

<Effects of the Invention> According to the present invention, when the optical fiber cable is laid in the pipe by flowing gas into the pipe and conveying the optical fiber cable in the downstream direction by this flow, as a pre-process when laying the optical fiber cable in the pipe, By force-feeding the fluid into the pipe, it is possible to eliminate the residue in the pipe that becomes an obstacle to the transport of the optical fiber cable.
It is possible to prevent a decrease in the transport speed of the optical fiber cable due to the residue, and the efficiency of the installation work can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of an optical fiber cable, FIG. 2 is a perspective view showing a cable pipe in which the optical fiber cable is installed, and a collecting pipe in which the cable pipes are bundled. , Equipment configuration 1 when installing optical fiber cable
FIG. 4 is a schematic sectional view of the configuration of the pressure feeding head. In the drawing, 11 is an optical fiber cable, 13 is an optical fiber, 15 is a cable tube, 17 is a collection pipe, 19 is a pit, 2
3. ．． 25 is a manhole, 22 and 24 are extension pipes, 26 is a cable pumping device, and 28 is a pumping head. Figure 3 Figure 4 1986 Patent Application No. 181688 21 Name of the invention Cable laying and recovery method 3 Relationship with the person making the amendment Patent applicant, ゛1; 4-5-33 Kitahama, Chuo-ku, Osaka, Japan (213) Sumitomo Electric Industries Co., Ltd. 4, Agent Postal code 107 Japan Shortwave Broadcasting Center, 9-15 Akasaka-chome, Minato-ku, Tokyo Telephone number: 58317058 - 6 , "Detailed Description of the Invention" column of the specification to be amended, Drawing 7, and the content of the amendment (Amend Figure 2 of the 11 drawings as shown in the attached amended drawing. (2) Line 17 on page 7 of the specification ``Cable #I!!15'' written from the 8th page to the 5th line
It can also be made flexible. ” to be deleted. 8 List of attached documents (1) Amended drawings 1 copy (or more) Same location

Claims (2)

[Claims] (1) By flowing gas into the pipe and transporting the cable in the downstream direction by this flow, when the cable is laid in the pipe or recovered from the pipe, as a pre-process, by flowing gas into the pipe, the cable is A method for laying and recovering a cable, characterized in that residual matter in the pipe that becomes an obstacle to the conveyance is removed. (2) When installing the cable in the pipe or recovering the cable from the pipe by flowing gas into the pipe and transporting the cable downstream by this flow, as a pre-process, first pour a liquid into the pipe and then add gas. A method for laying and recovering a cable, characterized in that the inside of the pipe is dried by flushing the pipe with water, and residues inside the pipe that become an obstacle to the conveyance of the cable are removed.