JP2004246173A - Pipe cable for air pressure feeding and air pressure feeding method for optical cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe cable for air pressure feeding which improves the insertability of an optical cable into pipes for an air pressure feeding in the cable. <P>SOLUTION: The pipe cable 100 for air pressure feeding having a plurality of the pipes 120 for air pressure feeding is inverted in a collection direction of the pipes 120 for air pressure feeding at specified intervals and therefore the pipe cable with which the smooth insertion of the optical cable is possible can be obtained. Also, a pressure-feedable distance can be made longer and further the line speed during the pressure-feeding can be improved. Further, the improvement in leading workability in midway of the pipe cable is possible as well. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to a pneumatic feeding method for a pneumatic feeding pipe cable and an optical cable, and aims at improving the penetrability (pumping property) of an optical cable such as an optical fiber unit into the pneumatic feeding pipe in the cable.
[0002]
[Prior art]
The pneumatic transmission pipe cable usually has a plurality of pneumatic transmission pipes, and is laid in advance in a building or a predetermined cave, and if necessary, an optical cable such as an optical fiber unit is formed by the pneumatic transmission method. , For passing through a pneumatic feeding pipe.
[0003]
Various pipes having such structures have already been proposed as such a pneumatic pipe cable. For example, as a composite type, a plurality of the above-mentioned plurality of pipe cables are provided outside a tensile member (tension member) at a central portion. There is a cable in which pipes for pneumatic feeding are twisted and assembled. (See Patent Document 1).
[0004]
[Patent Document 1]
JP-A-11-149022 (pages 1-2, FIG. 2)
[0005]
[Problems to be solved by the invention]
However, in the pipe cable of the conventional structure as described above, when the pneumatic feed pipes are twisted and assembled, they are usually continuously twisted in one direction along the longitudinal direction (one-way twisting). Therefore, when viewed from the entire length of the cable, the pneumatic pipe itself is continuously twisted in a spiral shape (helical shape) along the longitudinal direction. When the optical fiber unit is to be inserted into the continuously spirally twisted pipe together with the airflow by the air pressure feeding method, the torsion becomes a resistance, and the insertion of the optical fiber unit gradually occurs. There was a problem that it became difficult. That is, this causes a problem that the pumpable distance is shortened and the linear velocity at the time of pumping is also reduced.
[0006]
In particular, in recent years, with the increase in demand for lines, the number of optical fibers in the optical fiber unit has increased, and the outer diameter and mass of the unit have tended to increase. It has become a major problem that cannot be ignored. Furthermore, in order to respond to a larger demand for a line, when an optical fiber unit in which an optical fiber ribbon is laminated is used as an optical fiber unit, in the case of this kind of cable, the direction of bending is generated, that is, In the laminated portion of the tape core wire, although relatively easy to bend in the vertical direction (vertical direction), large rigidity is generated in the width direction (horizontal direction) and it is difficult to bend. The resistance due to the torsion will work even more.
For this reason, there is a serious problem that only a shorter pumping distance can be obtained or insertion can be performed only at a lower linear velocity.
[0007]
The present invention has been made in view of such a conventional situation, and when twisting a plurality of pneumatic feeding pipes, the assembly direction is inverted at regular intervals to thereby reduce the resistance due to twisting of the pipe itself. Therefore, it is intended to provide a pipe cable for pneumatic feeding which facilitates the insertion of the optical cable thereafter. In addition, the use of this pipe cable does not provide a method of pneumatically feeding an optical cable that can be smoothly inserted even in an optical cable in which optical fiber tape cores and the like are laminated and the bend has directionality. It is assumed that.
[0008]
[Means for Solving the Problems]
The present invention according to claim 1 is a pneumatic feeding pipe cable having a plurality of pneumatic feeding pipes, wherein a gathering direction of the pneumatic feeding pipes is reversed at regular intervals. In the pipe cable.
[0009]
According to the second aspect of the present invention, the reversal of the assembly direction of the pneumatic feeding pipe is performed at a rate of once for every three twists of the pneumatic feeding pipe to once for every twenty twists. 2. The pneumatic feeding pipe cable according to claim 1, wherein:
[0010]
According to a third aspect of the present invention, an optical fiber unit having an optical fiber tape core laminated therein is inserted into the air pressure feeding pipe of the air pressure feeding pipe cable according to the first or second aspect together with an air flow. A method for pneumatically feeding an optical cable.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an embodiment of a pneumatic feeding pipe cable according to the present invention. The pipe cable 100 has at least a tensile member (tension member) 110 at a central portion or in the vicinity thereof. A plurality of pneumatic pressure feeding pipes 120 are twisted and gathered outward, and these are held down by a presser winding 130. After that, a jacket 140 is applied.
[0012]
Note that this structure is only a basic structure, and in actuality, if necessary, an appropriate interposition is provided between the tensile strength member 110 and the pneumatic pressure feeding pipe 120. Similarly to the above, it may be combined with an optical fiber for a sensor or the like, and further, a steel strip exterior or an anticorrosion layer may be applied to the outside of the jacket 140. Further, the strength member 110 itself can also be used as the pneumatic feeding pipe 120 made of a high-strength stainless steel metal pipe or the like. In addition, as the tensile strength member 110, a non-metallic type made of FRP (reinforced plastic) wire or the like, which has no problem such as electromagnetic induction, and uses a resin-coated steel stranded wire or a solid steel wire. You can also.
[0013]
In the present invention, when the plurality of pneumatic feeding pipes 120 are twisted and assembled, the assembling direction is reversed at regular intervals. That is, it is SZ twist. This SZ twist is also called left and right alternate twist, and in this example, after the air pressure feeding pipe 120 is twisted several times in one direction, after a certain distance, the twisting direction is changed. Is a method of twisting by reversing and twisting.
[0014]
By adopting this SZ twist, the plurality of pneumatic feeding pipes 120 are not twisted in a spiral shape continuously in one direction along the longitudinal direction.
Thereby, in the pipe cable 100 of the present invention, the resistance against insertion due to continuous twisting of the air pressure feeding pipe 120 itself is reduced. When it is inserted, smooth insertion becomes possible.
[0015]
In other words, the smooth insertion makes it possible to lengthen the pumpable distance and improve the linear velocity during the pumping. Of course, the settable section of the pumping device system can be lengthened as much as the pumpable distance can be lengthened, so that the cost can be reduced. In addition, when the linear velocity is increased, the time required for the partial pressure feeding is shortened, so that improvement in workability can be expected.
[0016]
According to tests by the inventors of the present invention, the condition of SZ twisting that enables such smooth insertion is in the range of 1 to 3 twists to 1 to 20 twists. It is desirable to invert with. In other words, if the inversion is more than one for three twists, the inversion is too frequent, and if an external force such as bending or twisting is applied to the pipe cable 100, the pipe will easily cave. Conversely, there is a problem that twisting is likely to return, and conversely, if the number of inversions is less than one for 20 twists, the number of inversions is too small and the resistance due to twisting cannot be reduced too much.
[0017]
This smooth insertion is achieved not only in the optical fiber unit in which the single optical fiber core is twisted but also in the optical fiber tape 210 having the directionality in bending as shown in FIG. This is also possible in the optical fiber unit 200 in which is laminated. As described above, when the optical fiber ribbons 210 are laminated, the laminated portion is relatively easily bent in the vertical direction (vertical direction), but is relatively easily bent in the width direction (horizontal direction). Therefore, it is difficult to bend the cable because of its high rigidity, so that it is difficult or sometimes impossible to insert the cable with a normal conventional pipe cable. Here, reference numeral 220 denotes a coating layer of the optical fiber ribbon 210, and reference numeral 230 denotes a jacket thereof.
[0018]
As described above, when the pipe cable 100 of the present invention is used, even in the case of an optical cable having a directionality in bending as in the case of the optical fiber unit 200, it can be smoothly inserted in a normal pneumatic feeding method. , Excellent pneumatic feeding method is obtained.
[0019]
<Example>
In the pipe cable having the same structure as that of FIG. 1, six pneumatic feeding pipes 120 each having an outer diameter of 8 mm and an inner diameter of 6 mm are assembled outside the tensile strength member 110 by SZ twist. In this SZ twist, the inversion was performed once every five times. Then, an outer jacket 140 was applied on these via a presser winding 130 to make the entire outer diameter 28 mm. Here, a steel stranded wire having an outer diameter of 8 mm coated with polyethylene was used as the tensile strength member 110, and a high-density polyethylene pipe with low friction was used as the pipe 120 for air pressure feeding.
[0020]
Then, as shown in FIG. 2, the optical fiber unit 200 having the optical fiber ribbons 210 laminated thereon was inserted into the pneumatic feeding pipe 120 of the pipe cable together with the airflow by the pneumatic feeding method. It was able to be inserted in about 53 minutes for a cable length of 1500 m. In addition, as a precautionary measure, the reversal of the SZ twist is performed in the range of 1 time for 3 times of twisting to 1 time for 20 times of twisting, that is, 3: 1 in addition to the above 5: 1. When various tests were performed on the cases of 10: 1, 15: 1, and 20: 1, all of them could be inserted within about 60 minutes. For comparison, in the test in which the pipe cable 100 was twisted in one direction, it took about 89 minutes. From this, it can be seen that in the case of the present invention, the insertion can be performed at a high insertion speed, and the insertion property (pumping characteristics) is improved.
[0021]
【The invention's effect】
As is apparent from the above description, according to the pneumatic feeding pipe cable according to the present invention, since a plurality of pneumatic feeding pipes are SZ twisted, smooth insertion of an optical cable such as an optical fiber unit is obtained. Can be
Thereby, the pumpable distance can be increased, and the linear velocity at the time of pumping can be improved. In addition, by using SZ twist, it is easy to obtain the extra length of the pneumatic feeding pipe at the time of tapping work in the middle of the pipe cable, so that tapping can be easily performed without cutting other pipes. it can.
[0022]
Further, in the pneumatic feeding method of the optical cable according to the present invention, since the pipe cable for pneumatic feeding by the SZ twist is used, even in the case of an optical cable such as an optical fiber unit having an optical fiber tape core laminated inside, it can be smoothly. Can be inserted.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing one embodiment of a pipe cable for pneumatic feeding according to the present invention.
FIG. 2 is a schematic longitudinal sectional view showing an example of an optical cable inserted into a pneumatic pipe in the cable of FIG.
[Explanation of symbols]
REFERENCE SIGNS LIST 100 Pneumatic feeding pipe cable 110 Tensile member 120 Pneumatic feeding pipe 130 Presser winding 140 Jacket 200 Optical fiber unit 210 Optical fiber tape core

Claims (3)

What is claimed is: 1. A pneumatic feeding pipe cable having a plurality of pneumatic feeding pipes, wherein a gathering direction of said pneumatic feeding pipes is reversed at regular intervals. The reversal of the assembly direction of the pneumatic feeding pipe is performed at a rate of once for three twists of the pneumatic feeding pipe to one for 20 twists. Pipe cable for pneumatic feeding. 3. The air pressure of an optical cable, wherein an optical fiber unit having an optical fiber ribbon laminated therein is inserted into the air pressure pipe of the air pressure pipe cable according to claim 1 or 2 together with the air flow. Sending method.

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