JP2000147342A - Pneumatic feeding method of optical cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical cable pneumatic feeding method which facilitates the pneumatic feeding of the optical cable into master pipes embedded underground, etc., and facilitates the removal of connecting materials after laying of the optical cable. SOLUTION: Sheath pipes 6a, 6b and 6c are inserted into the master pipes 1a to 1c respectively from hand holes 2a, 2b and 2c disposed at prescribed intervals and thereafter, these sheath pipes 6a, 6b and 6c are connected to each other by connecting pipes 7a and 7b within the hand holes 2a, 2b and 2c and are connected by connectors, by which hermeticity is maintained. As a result, the escape of compressed air to the atmosphere is prevented when the optical cable 3 is pneumatically fed into the sheath pipes 6a, 6b and 6c by using a pneumatic device 8. The optical cable 3 may thus be continuously inserted at a time into the sheath pipes 6a, 6b and 6c. The connecting pipes 7a and 7b having flexibility may be removed from the sheath pipes 6a, 6b and 6c by cutting these connecting pipes after the force feeding of the optical cable 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cable pneumatic feeding method.

[0002]

2. Description of the Related Art Communication cables, optical cables and the like are laid using compressed air in buried pipes buried underground or the like, and aging cables are replaced with new cables.

FIG. 6 is an explanatory view of a conventional optical cable pneumatic feeding method.

As shown in FIG. 1, hand holes (hereinafter, referred to as "HH") 2a, 2b are provided at predetermined intervals in the middle of master pipes (buried pipes) 1a, 1b, 1c buried underground or the like. ing. A parachute-shaped pressure receiving and traction tool 4 is temporarily connected to the tip of the new optical cable 3 and compressed air blown from the wire passing device 5 causes one (the right in the figure) HH2b to enter the other (the left in the figure) into the buried pipe 1b. )) By pulling the optical cable 3 to the HH 2a with the pressure receiving traction tool 4. Alternatively, a wire rod connected with a wire rope, etc., is inserted into the buried pipe, the wire rod is pulled out, then the wire rope is connected to the end of the cable, and this is pulled by a cable pulling machine (winch) or the like. (Not shown).

[0005]

In the conventional optical cable pneumatic feeding method described above, since the optical cable is connected by utilizing the internal pressure difference in the buried pipe due to the compressed air, the connection to a single span is performed. Although it is possible, for example, when the buried pipe is connected in a plurality of spans in a handhole for maintenance and inspection, the compressed air escapes to the atmosphere in HH or the like, so the tractive force by the parachute is used. And the work is interrupted.

In addition, since the length of the connecting rod is about 200 to 300 m, the connecting rod cannot be continuously connected in a plurality of spans, resulting in poor working efficiency.

[0007] Despite these problems, when the main pipe (buried pipe) is connected in a relay in an HH or the like, the sheath pipe in the main pipe is hermetically sealed while maintaining the mutual internal pressure. There was no continuous route method for handhole passing that was performed by connecting.

[0008] Generally, the span between HH is standard 250 m, and the sheath tube is also laid in the master tube every 250 m span. For example, when an optical cable having a length of 1000 m is laid in a long pressure, the sheath tubes must be connected within the HH every 250 m, and the use of a relay connection is an essential condition.

However, since air pressure is applied to the inside of the sheath tube, pressure resistance and airtightness are required at the junction. In addition, the relay connection part must have a structure with excellent workability to smoothly feed the optical cable into the sheath tube, and it is easy to take extra length after laying the optical cable by pressure. A structure that can be completely removed is required.

Accordingly, an object of the present invention is to solve the above-mentioned problems, to easily pneumatically feed an optical cable into a parent pipe buried underground or the like, and to easily remove a connection material after laying the optical cable. To provide a construction method.

[0011]

In order to achieve the above object, an optical cable pneumatic feeding method according to the present invention is directed to an optical cable pneumatic feeding method for pneumatically feeding an optical cable into a parent pipe buried underground or the like. After inserting the sheath tubes from the hand holes provided at intervals, the sheath tubes were connected to each other with a flexible connection pipe in each hand hole, and each connection pipe and each sheath tube were connected with a connection fitting. rear,
The optical cable is pneumatically fed from one end of the continuous sheath tube.

In addition to the above configuration, the optical cable pneumatic feeding method according to the present invention provides an optical cable in which a pipe-like guide having a diameter substantially equal to that of the sheath tube is inserted into the connecting pipe in the handhole so as to abut both end surfaces of the sheath tube. May be pneumatically fed.

In the optical cable pneumatic feeding method of the present invention, in addition to the above configuration, the optical cable may be pneumatically fed using a guide having a groove formed in the longitudinal direction.

In addition to the above configuration, in the optical cable pneumatic feeding method of the present invention, the optical cable may be pneumatically fed using a guide provided with a tear string in a longitudinal direction.

According to the present invention, an optical cable is pneumatically fed into a sheath tube by maintaining the airtightness by connecting the sheath tubes with a flexible connection pipe in a handhole and connecting them with a connection fitting. In this case, the compressed air is prevented from escaping into the atmosphere. As a result, even if the sheath pipe is connected in a plurality of spans, the optical cable into the sheath pipe can be continuously passed through the air pipe using the pneumatic feeding device. In addition, a pipe-shaped guide with a diameter approximately equal to that of the sheath
The insertion work of the connecting pipe is facilitated by inserting so as to abut against both end surfaces of the sheath tube. Further, after the optical cable is pumped, the flexible connection pipe can be removed from the sheath tube by cutting. Further, when the guide is provided with a groove or a tear string, the optical cable is smoothly fed under pressure, and the work of removing the connection material such as the guide after the optical cable is laid is facilitated.

[0016]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the same members as those in the conventional example shown in FIG.

FIG. 1 is a conceptual diagram showing one embodiment of the optical cable pneumatic feeding method of the present invention.

In this optical cable pneumatic feeding method, the sheath pipes 6a, 6b, and 6c are respectively provided from HHs 2a, 2b, 2c provided at predetermined intervals in parent pipes 1a, 1b, 1c buried underground or the like.
After insertion of 6b, 6c, the sheath tube 6 is inserted into each HH 2a, 2b.
a, 6b, 6c are connected to each other by flexible connecting pipes (or connecting hoses) 7a, 7b, and each connecting pipe 7
a, 7b and the respective sheath tubes 6a, 6b, 6c are connected by connecting fittings (not shown), and then the continuous sheath tubes 6a, 6
The optical cable 3 is pneumatically fed by the pneumatic feeding device 8 from one end of each of b and 6c.

As described above, in each of the HHs 2a, 2b, and 2c, the sheath tubes 6a, 6b, and 6c are connected to each other by the flexible connection pipes 7a and 7b, and the sheath tubes 6a, 6b, and 6 are connected to each other by connecting fittings.
By maintaining the airtightness in c, the sheath tubes 6a, 6b,
The compressed air is prevented from escaping into the atmosphere when the optical cable 3 is pneumatically fed into 6c. As a result, the sheath tubes 6a, 6
Even if b and 6c are connected in a multi-span relay connection, the air cable 3 can be used to allow the optical cable 3 to pass through the multi-span such as HH into the sheath pipes 6a, 6b and 6c at a stretch. Further, after the optical cable is pressure-fed, the flexible connection pipes 7a and 7b are cut so that the sheath pipes 6a and 6b are cut.
b, 6c. In the figure, HH
The number of 2a, 2b, 2c is three, and the sheath tubes 6a, 6b,
6c and three connecting pipes 7a and 7b.
It is a book but is not limited.

[0020]

(Embodiment 1) FIG. 2 (a) is a cross-sectional view of a connecting pipe used in the optical cable pneumatic feeding method of the present invention, and FIG. 2 (b) is a line AA of FIG. 2 (a). It is sectional drawing.

A connecting pipe 7a was used as a relay connecting portion between the sheath pipes 6a and 6b, and both ends of the connecting pipe 7a were fixed at a plurality of locations with connecting fittings 9, respectively. The material of the connecting pipe 7a was made of plastic (or rubber).

(Embodiment 2) FIG. 3A is a cross-sectional view of a connecting pipe used in the optical cable pneumatic feeding method of the present invention, and FIG. 3B is a cross-sectional view taken along line BB of FIG. 3A. FIG.

FIGS. 5A to 5G are cross-sectional views of a guide used for the connecting pipe shown in FIG.

The difference from the embodiment shown in FIGS. 2 (a) and 2 (b) is that a connecting pipe 7a is used for the relay connection between the sheath tubes 6a and 6b, and the optical cable 3 is provided inside the connecting pipe 7a. The point is that a guide 10 for smoothing the pressure feeding is provided. The material of the guide 10 is polyethylene, and FIG.
A guide having a shape shown in FIGS.

Here, the method of connecting the sheath tubes 6a, 6b and the connecting pipe 7a was performed as follows.

After the guide 10 is inserted into the connecting pipe 7a, the sheath pipes 6a and 6b are inserted from both ends of the connecting pipe 7a until they abut against the end face of the guide 10, respectively. The relay connection part was formed by fastening and fixing the pipes 6a and 6b. The material of the connecting pipe 7a is the same as the material shown in the first embodiment.

(1) The guide 10a shown in FIG. 5 (a) is a polyethylene pipe having a half-split structure. After inserting the guide 10a into the connecting pipe 7a, the sheath pipes 6a and 6b are inserted from both ends of the connecting pipe 7a until they abut against the end face of the guide 10a, and the end of the connecting pipe 7a and the sheath pipe 6a are connected by the connecting fitting 9. 6b was fastened and fixed to form a relay connection portion. Thereby, the sheath tube 6
There is no step between the end faces of a and 6b and the connecting pipe 7a,
The optical cable 3 can be smoothly pressure-fed. Since the guide 10a has a half-split shape, it is excellent in workability and can be easily removed after the optical cable 3 is fed.

(2) The guide 10b shown in FIG. 5B has a structure in which a part of a polyethylene pipe is cut in the longitudinal direction. Since the guide 10b cuts only a part of the polyethylene pipe in the longitudinal direction, it is possible to avoid a deviation between the end faces of the half-split pipes like the guide 10a shown in FIG. This guide 10b is shown in FIG.
It is excellent in workability similarly to the guide 10a shown in (a), and can be easily removed after pressure feeding.

(3) In the guide 10c shown in FIG. 5C, a plurality of grooves 11 are formed in the surface of the polyethylene pipe in the longitudinal direction, and the thickness of the pipe is partially reduced. The guide 10c can be easily removed by cutting the groove 11 with a cutter or the like. Also, this guide 1
0c does not cut a part of the polyethylene pipe, so that the guides 10a and 10b shown in FIGS.
It is more rigid than. This guide 10c is excellent in workability like the guide 10a shown in FIG.
Can be easily removed after pumping.

(Embodiment 3) FIG. 4 (a) is a cross-sectional view of a connecting pipe used in the optical cable pneumatic feeding method of the present invention, and FIG. 4 (b) is a cross-sectional view taken along line CC of FIG. 4 (a). FIG.

The difference from the embodiment shown in FIGS. 3 (a) and 3 (b) is that a flexible corrugated polyethylene pipe 12 is used at the junction between the sheath tubes 6a and 6b to improve airtightness. In order to hold the corrugated polyethylene pipe 12, both ends of the corrugated polyethylene pipe 12 are fixed by special heterogeneous pipe joints 13 for the corrugated pipe (joint for connecting the sheath pipe and the corrugated polyethylene pipe at a time). This corrugated polyethylene pipe 12
Is flexible even when, for example, the positions of the parent tubes 1a and 1b facing each other in the HH 2a are displaced in any of up, down, left, and right directions, so that there is an advantage that the connection is flexible to some extent.

(Embodiment 4) Guide 10 shown in FIG.
d has a structure in which the tear string 14 is inserted into the polyethylene pipe, and can be easily removed by pulling the tear string 14 after the optical cable 3 is fed and tearing the guide 10d.

(Embodiment 5) Guide 10 shown in FIG.
5e is characterized in that the tear string 14 is extruded together with the polyethylene when the polyethylene pipe is manufactured, and has excellent workability and can be easily removed after the optical cable is pressure-fed, similarly to the guide 10d shown in FIG. 5D.

(Embodiment 6) Guide 10 shown in FIG.
f is a plurality of grooves 1 in the longitudinal direction of the surface of the polyethylene pipe.
1 and a structure in which the thickness of the pipe is partially reduced, and the tear string 14 was extruded together with the polyethylene when the polyethylene pipe was manufactured, similarly to the guide 10e shown in FIG. 5 (e). Features. This guide 10f is similar to the guide 10d shown in FIG.
It has excellent workability and can be easily removed after optical cable pressure feeding.

(Embodiment 7) Guide 1 shown in FIG.
0g is the tear string 1 on the guide 10c shown in FIG.
4 is inserted. This guide 10g has excellent workability similarly to the guide 10d shown in FIG. 5D, and can be easily removed after optical cable pressure feeding.

[0036]

In summary, according to the present invention, the following excellent effects are exhibited.

It is possible to provide an optical cable pneumatic feeding method in which the optical cable can be easily pneumatically fed into a parent pipe buried underground or the like and the connection material can be easily removed after laying the optical cable.

[Brief description of the drawings]

FIG. 1 is a conceptual view showing an embodiment of the optical cable pneumatic feeding method of the present invention.

FIG. 2A is a cross-sectional view of a connecting pipe used in the optical cable pneumatic feeding method of the present invention, and FIG.
FIG. 4 is a sectional view taken along line AA of FIG.

3A is a cross-sectional view of a connecting pipe used in the optical cable pneumatic feeding method of the present invention, and FIG.
FIG. 7 is a sectional view taken along line BB of FIG.

4A is a cross-sectional view of a connecting pipe used in the optical cable pneumatic feeding method of the present invention, and FIG.
It is CC sectional view taken on the line of FIG.

5A to 5G are cross-sectional views of a guide used for the connecting pipe shown in FIG.

FIG. 6 is an explanatory view of a conventional optical cable pneumatic feeding method.

[Explanation of symbols]

 2a, 2b, 2c Hand hole (HH) 6a, 6b, 6c Sheath tube 7a, 7b Connecting pipe 8 Pneumatic feeding device 9 Connection fitting

Claims (4)

[Claims] In an optical cable pneumatic feeding method for pneumatically feeding an optical cable into a parent pipe buried underground or the like, a sheath pipe is inserted from a handhole provided at a predetermined interval in the parent pipe, and then each handhole is inserted. After connecting the sheath pipes with a flexible connecting pipe within the connecting pipes and connecting each connecting pipe and each sheath pipe with a connecting fitting, the optical cable is pneumatically fed from one end of the continuous sheath pipe. Optical cable pneumatic feeding method. 2. The optical cable is pneumatically fed by inserting a pipe-like guide having a diameter substantially equal to that of the sheath tube into the connecting pipe in the handhole so as to abut against both end surfaces of the sheath tube. The optical cable pneumatic feeding method described in 1. 3. The optical cable pneumatic feeding method according to claim 2, wherein the optical cable is pneumatically fed using a guide having a groove formed in a longitudinal direction. 4. The optical cable pneumatic feeding method according to claim 2, wherein the optical cable is pneumatically fed using a guide provided with a tear string in a longitudinal direction.