JPH02131312A - Cable laying method onto inner face of conduit - Google Patents

Abstract

PURPOSE:To facilitate laying of cable by adhering a cable to the inner wall of a conduit then adhering a tube to the inner wall of the conduit, thereby supporting and securing the cable. CONSTITUTION:An optical cable 3 is temporarily secured through adhesive 4 to the inner wall at the upper section of a conduit 2. Then a folded tube 1 is penetrated into the conduit 2. The terminal of the tube 1 inserted into the conduit 2 are closed, then compressed air is ejected to the inside of the tube from the inlet side. The compressed air is mixed with epoxy adhesive in the shape of spray. The adhesive is applied entirely onto the inner wall of the conduit 2 through fine holes made through the tube 1, thus adhering the tube 1 to the inner wall while simultaneously clogging the pits of the tube 1 and coating the inner face.

Description

[Detailed Description of the Invention] A. INDUSTRIAL APPLICATION FIELD The present invention relates to a method for laying cables on the inner surface of a conduit, and particularly to a method for laying cables on the inner surface of a conduit B. in which a tube is expanded with compressed air to fix the cable. Summary of the Invention The present invention aims to provide a method for supporting and fixing cables installed on the inner surface of a conduit. By inflating the tube with compressed air mixed with adhesive and adhering it to the inner wall of the conduit, the cable is safely and reliably supported and fixed.

C. Conventional technology In the past, electrical signals were transmitted using electric wires in telecommunications, but as an alternative to this, optical transmission, which converts electrical signals into laser beams and transmits them, was developed, and optical cables were used as transmission lines. It has become widely used in recent years.

Optical cable transmission lines were installed on utility poles and strung out in the air, but their reliability as electrical lines was limited. For aesthetic reasons, underground conduits are being installed underground. Recently, attempts have been made to make use of the sewage pipes that are arranged like a web in the city, and to run optical cables through these pipes to create a communication network.

Therefore, optical cables had to be laid out in small-diameter conduits that people could not access, and various methods as shown in Fig. 3 were used to lay them out. The method of laying the optical cable 101 shown in FIG. 3 (+L) is the simplest method in which the optical cable 101 is placed alone on the bottom of the conduit 2 and laid.

The next figure (b) shows a method of supporting and attaching the optical cable 101 to the inner wall (generally the upper part) of the conduit 2 by gluing it. (c) The figure shows a method in which a support fitting 102 such as a saddle is fixed to the inner wall of the conduit 2, and the optical cable 101 is supported and attached by the support fitting 102, and (d) the figure shows a method in which the optical cable 101 is housed in the conduit 2. Cable installation sheath belt 103
This is a method in which the sheath band is fixed to the inner wall of the conduit using a support fitting 102 such as a saddle.

The above-mentioned optical cable installations were all carried out using installation robots that were able to move freely within the conduits.

D. Problems to be Solved by the Invention However, the following problems have arisen in the conventional methods of fixing optical cables using the various means described above. First, the installation of optical cables creates protrusions inside the pipes, which can become obstacles and cause sludge to accumulate.
In addition, since the cable comes into direct contact with sludge, etc., the cable is susceptible to corrosion.

Second, when supporting an optical cable with a support metal fitting,
If the supporting metal fittings are fixed by adhesive, it is easy to cause deterioration of the adhesive support part due to aging and variations in the supporting force due to construction accuracy.Also, it is essential to use a laying robot when installing the cable, and the third problem is that the work efficiency is low. In recent years, high-pressure jet cleaning is often used for cleaning methods such as dredging, and the cleaning water and cleaning equipment tend to cause detachment of support fittings and damage to optical cables.

Fourthly, the method of storing the optical cable in a sheath for installation and fixing it inside the pipe with a supporting metal fitting does not cause corrosion of the optical cable, but it is difficult to construct around curved parts of the pipe, and the workability is low.

The present invention has been made in view of the above-mentioned problems to be solved.
An object of the present invention is to provide a cable installation method for securely and easily fixing an optical cable in a conduit.

E. Means for Solving the Problems The present invention provides a method for supporting a cable, in which the cable is supported and fixed by gluing the entire circumference of the inner wall of the conduit with a tube.
After gluing and fixing the cable to the inner wall of the conduit, a stretchable tube with pores penetrating through the wall is expanded with compressed air mixed with adhesive and adhered to the inner wall of the conduit to support and fix the cable. It is characterized by

F. Effect: By using the above method, the tube is expanded in the pipe by compressed air and tightly adheres to the inner wall of the pipe, and the adhesive passes through the pores of the tube and is attached to the tube along with the cable that has been previously glued to the inner wall of the pipe. The entire circumferential surface is firmly adhesively fixed to the inner wall of the pipe.

G. Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1 shows the appearance of the tube used in the embodiment of the present invention, and Figure (a) shows the appearance of the tube when expanded.
(b) is an external view of the tube in a folded state before inflation. The tube I is made of a stretchable epoxy resin film material, and is formed to have various diameters and lengths depending on the diameter and length of the pipe line used. Tube again! As shown in FIG. 1(a), a large number of pores 1a having minute diameters are provided on the entire circumferential surface of the tube in the thickness direction (radial direction), penetrating through the wall thickness.

In a steady state before construction, the tube 1 is stored in a folded state as shown in FIG. 1(b).

A cable installation method according to this embodiment using the tube 1 described above will be explained. Figures 2 (a), (b) and (C) show the construction order of cable installation in the cross section of the pipe.
As shown in the figure, first, the optical cable 3 is temporarily fixed to the upper inner wall of the conduit 2 using an adhesive 4. In this embodiment, the optical cable 3 used is of a flat rectangular shape, which is suitable because it allows a large bonding area. The adhesive 4 used in this case does not need to be a special one, as long as it can temporarily fix the optical cable 3 to the inner wall of the conduit with its adhesive force. This temporary fixing work can be easily performed using a laying robot that can move inside the pipe line 2.

Next, as shown in the figure (b), the tube I in the folded state is penetrated into the interior of the conduit 2. In this case, the optical cable 3 is temporarily fixed to the upper inner wall of the conduit 2. The terminal end of the tube I inserted into the conduit 2 is closed, and compressed air is jetted inside the tube I from the inlet side. In this case, the epoxy adhesive is mixed with the compressed air in the form of a mist and is ejected. The atomized adhesive sent into the tube 1 together with compressed air passes through each of the many pores 1a formed in the tube 1 and is applied to the entire circumference of the inner wall of the conduit 2. At the same time, the adhesive adheres the outside of the tube 1 expanded by the pressure of the compressed air to the inner wall of the conduit 2, and also coats the inner surface of the tube 1 by closing the pores of the tube 1. (c) The figure shows a state in which the optical cable 3 is supported and fixed by the tube 1 glued to the conduit 2. As shown in the figure, the optical cable 3, which was temporarily fixed, is firmly fixed to the inner wall of the conduit 2 by the tube 1. be done.

Therefore, the adhesive penetrating from the inner surface of the tube 1 hardens the tube 1 and turns it into a lining material with high wear resistance. As the tube used in the present invention, it is preferable to use the utility model registration application ``Pipe inner surface coated tube'' filed by the applicant on the same day as the present invention.

In carrying out the present invention, I-. It goes without saying that the present invention is not limited to the embodiments described above, and that the cable to be fixed and supported by the tube is not limited to an optical cable, but may be any other type of filament.

H. Effects of the Invention As explained above, the present invention involves adhesively fixing a cable to the inner wall of a conduit, and then inflating a telescopic tube with pores penetrating the wall using compressed air mixed with an adhesive. By using the method of supporting and fixing the cable by adhering it to the inner wall of the conduit, firstly, the cable is supported and fixed on the entire inner wall of the conduit, which is strong and can be easily installed against bends in the conduit. .

Second, cables can be easily installed in small-diameter conduits that are difficult to support with conventional cable installation methods.

Thirdly, there is no need for protrusions such as support fittings for cable support and fixation, so there is an advantage that the pipe cross-sectional area does not become small.
The protection of the cable during dredging inside the pipeline is ensured.

Fourthly, by coating the entire inner surface of the pipe with a tube, the pipe can be lined, which has great effects such as reinforcing the pipe and eliminating water intrusion and leakage from the outside.

[Brief explanation of the drawing]

Figure 1 is an external view of the tube used in the embodiment of the present invention.
FIG. 2 is a diagram showing the construction order of the cable installation method of this embodiment from a cross-sectional view of the pipe, and FIG. 3 shows an example according to the prior art. l...tube, 1a...pore, 2...pipeline, 3
... Cable (flat optical cable), 4... Adhesive. Figure 3 (a) (b) (C) (d)

Claims (1)

[Claims] (1) A method of laying a cable in a conduit, comprising:
After adhering and fixing the cable to the inner wall of the conduit, a telescopic tube with pores penetrating through the wall is expanded with compressed air mixed with adhesive and adhered to the inner wall of the conduit to support and fix the cable. A cable installation method on the inner surface of a conduit.