JPS60247203A - Drawing or leading-in method of optical fiber cable - Google Patents

Abstract

PURPOSE:To increase the limiting section length in the stage of drawing and leading in an optical fiber cable by supplying a liquid between the optical fiber cable and the inside peripheral surface of a protective cylinder to decrease the coefft. of friction between the optical fiber cable and the protective cylinder and to apply buoyancy to the optical fiber cable. CONSTITUTION:The end of a composite overhead earth wire 1 is held open and the protective cylinder 3 and the installed optical fiber cable 4 are stepwise exposed from the end face of a metallic stranded wire layer 2. A liquid supply device 5 is disposed and fixed to the end of the cable 4 and the cylinder 3. The end of the installed cable 4 and the end of the fresh optical fiber cable 10 are connected via a connecting means 9. The liquid L is supplied to a liquid reservoir 5 through a supply pipe 8. The cable 4 is pulled in an arrow direction and is drawn from the cylinder 3 at the point of the time when the liquid level rises above the bottom end face of the cable 4; at the same time, the cable 10 is led into the cylinder 3.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an original fiber cable used when replacing an original fiber cable incorporated in an elevated overhead ground wire in an original fiber composite overhead ground wire, etc. This article relates to the method of pulling out or pulling in.

[Prior art and its problems]

In recent years, a power/power composite cable line has been constructed by incorporating an optical fiber cable as an IHA transmission cable into an overhead ground wire installed together with a transmission line.

FIG. 2 shows an example of the above-mentioned optical/power composite couple, that is, an optical fiber composite overhead ground wire. A protective tube 3 is provided to form a hollow portion 3a, and an optical fiber cape/I/4 is inserted into the hollow portion 3a.

The above-mentioned optical fiber composite overhead ground wire l is stretched between support towers such as steel towers and is installed above the feeder tI#.

By the way, in this way, the hollow s3 a of the storage cylinder 3
The original fiber cable 4 installed at f/'3 has a loss of 91 hWk due to a narrowing of the capacity change, for example! −
If this happens, it will be necessary to replace it with a new optical fiber couple. Conventionally, in such cases, the existing optical fiber group 4 was disconnected between support towers, etc., including the section to be replaced, and the original fiber cable was pulled at one end by a pulling device such as a winch to protect it. A method is adopted in which the original fiber cable is pulled out from the cylinder 3 and similarly the original fiber cable to be newly installed is guided into the hollow part 3a of the retaining cylinder 3.

However, in this conventional method, the required Fyr load for pulling (pulling) the original fiber cable by the pulling device is mainly applied between the outer circumferential surface of the original fiber cable and the inner circumferential direction of the retaining cylinder 3. Determined by the resulting frictional force. On the other hand, the false tensile strength of the original fiber cable is limited by its tensile strength. Therefore, if the frictional force exceeds the tensile force, it becomes virtually impossible to pull out or draw in the original fiber cable, and generally it is impossible to pull out or pull out the inside of the maintenance tube 3 all at once. The continuous length of optical fiber cable that can be inserted is determined by the balance of two forces, and there is something called the critical section length. In the case of such conventional methods, because the frictional force mentioned above is large,
The critical section length is relatively short, which results in a relatively large number of connections in the 111ii circuit that cause loss of the original slow-transfer characteristics. Furthermore, as a matter of course, the original fiber cable must be pulled out and pulled in within a length range below the above-mentioned limit section length, which increases the number of operations, which is a major factor that hinders the rationalization of operations.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and provides a method for pulling out or pulling in a fiber cable in which the frictional force is small when pulling out or pulling in the fiber cable, and therefore, the length of the critical section described in 1) can be increased. The purpose is to provide

[Structure of the invention]

The method for pulling out or pulling in an optical fiber cable according to the present invention is such that when the original fiber group is passed through the leather running inside the hollow part of the holding cylinder, the optical fiber cable is inserted between the optical fiber couple and the inner circumferential surface of the holding cylinder. By supplying liquid, the coefficient of friction between the original fiber cable and the carrier cable is reduced, and buoyancy is given to the original fiber cable.

[Specific structure of the invention and its operation] FIG. 1 shows an embodiment of the invention, and the reference numeral 5 in the figure indicates the retention tube 3.
This is a liquid supply device that allows liquid to flow into the hollow portion 3a of the.

This liquid supply device 5 is provided with a fitting ring 6 for fitting the retaining tube 3 at one end of a substantially cylindrical main body 5a, and a seal ring unit 7 at the sacral end.
A supply pipe 8 for supplying liquid inward from the outside of the
It is made by connecting.

The main body 5a of the liquid supply device [5 has a central portion expanded in diameter to form a lumpy recess inside, and a liquid recess 5b is formed at the bottom of the lumpy recess. There is. A hole 5C is pressed into the top of the main body 5a,
The supply v8 is inserted and fixed into this hole 5C so as to communicate with the inside of the annular recess.

The fitting ring 6 is a thick-walled cylindrical body made of a highly elastic material such as oil-resistant synthetic rubber, and its inner diameter is the same as that of the original fiber composite air space 111ill to which the liquid supply device 5 is attached. It is said that the outer diameter is slightly smaller than the outer diameter of No. 3. Further, the seal ring unit 7 has a configuration in which 2i seal rings 7a are arranged in series at intervals by a ring plate-shaped distance piece 7b. Here, the seal ring 7a is an annular member made of a highly elastic material such as oil-resistant synthetic rubber, and its inner peripheral end is bent inward of the liquid supply device 5. has been done. The inner diameter of this seal ring 7a is slightly smaller than the outer diameter of the original fiber cable 4.

One embodiment of the method for pulling out or pulling in a fiber cable according to the present invention using such a liquid supply device 5 will be described below.

First, as a preliminary work, the end of the composite overhead ground wire 1 is opened at the jumper S of the support tower, etc., and the layered free end is stripped off in stages and the protection tube 3 is separated from the end face of the gold bullion stranded wire layer 2.
Then, the existing original fiber group 4 is exposed in stages over appropriate lengths. Then, the liquid supply device 5 is placed at the end of the protection tube 3 so that the original fiber couple 4 is inserted thereinto, and the fitting ring 6 is attached to the outer periphery of the end of the protection tube 3. The liquid supply device 5 is fitted to the end of the protective tube 3.

In this embodiment, in order to pull out the existing optical fiber cable 4 and pull in the new original fiber cable 10 at the same time, the cable is inserted into the liquid supply device 5 and extends from the seal ring unit 7 to the outside. One end 1 of the original fiber cable 10 to be led into the field via the end 4aK connection means 9 of the existing original fiber cable 4
Connect 0a.

Now, after the above-mentioned preparatory work has been completed, the liquid is injected into the liquid reservoir 5b in the liquid supply device 5 through the supply pipe 8.

Here, the liquid [is a surfactant diluted clear liquid such as soap water, a fatty lubricating oil made of fatty oil such as glyceride, a mineral oil-based lubricating oil such as spindle oil or turbine oil, and a liquid having S-mobility. Examples include low viscosity grease. Subsequently, when the liquid level in the liquid reservoir 5b becomes above the lower end surface of the optical fiber cable 4, a pulling device to which the end portion (not shown) of the optical fiber couple 40 is connected is connected. drive and fiber optic cable 4
is pulled out from the protection tube 3 by towing it in the direction of the arrow shown in the figure, and at the same time, a new original fiber cable IO is drawn into the protection tube 3.

In this step, the throat layer is interposed between the original fiber cable 4 or lO running in the hollow part 3a of the retaining cylinder 3 and the inner peripheral surface of the protective cylinder 3, and the original fiber cable is 4 or 10 receives the buoyant force due to the liquid, and the coefficient of friction between it and the inner circumferential surface of the protective cylinder 3 is also reduced. Therefore, the tension force between the original fiber cable and the inner surface of the holding cylinder is greatly reduced, and the tensile load required to pull out or pull in the original fiber cable 4.10 is greatly reduced. In other words, the above-mentioned limit section length of the original fiber cable can be greatly extended.

[Composition of the fairy of invention]

In the above embodiment, the case where the original fiber cable is pulled out and pulled in at the same time is explained, but the present invention is not limited to this, and the optical fiber cable may be pulled out or pulled in separately, and even in those cases. It goes without saying that a similar effect can be obtained. Further, the liquid may be forced to flow in the same direction as the running direction of the optical fiber coupler, and in this way, the above effect can be further enhanced.

As explained above, according to the present invention, liquid is supplied into the protective cylinder to give buoyancy to the original fiber cable, and
Since the optical fiber cable is towed and run inside the protective tube, the tensile load required to pull out or pull in the original fiber cable can be reduced, and the critical section length can be made longer. , it is possible to reduce the number of connecting parts and to streamline the above-mentioned pulling and pulling operations.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view showing an embodiment of a liquid supply device used in the method of the present invention, and FIG. 2 is a schematic cross sectional view showing an original fiber composite overhead ground wire. 1... Original fiber composite overhead ground wire, 2... Gold bullion twisted wire J
-13... Glaring tube, 3a... Hollow part, 1... Optical fiber cable, 5... Liquid supply device, 8...
Supply pipe, lO... former fiber cable, L... liquid. Applicant Fujikura Electric Wire Co., Ltd.

Claims (1)

[Claims] In this method, the original fiber cable is towed inside the hollow part of the protection cylinder and pulled out from the protection cylinder or pulled into the storage cylinder, by supplying liquid to the wrinkle protection cylinder to give buoyancy to the original fiber cable. A method for pulling out or pulling in an original fiber cable, characterized in that the optical fiber cable is towed and run in a protective cylinder while giving the same protection.