JP2984140B2 - Corrugated steel armored cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrugated steel pipe armored cable used for direct burying work and the like, and more particularly, to an outer surface of a corrugated steel pipe (still corrugated) which loses its moisture-proof effect for a long period of time. And a corrugated steel pipe armored cable capable of maintaining high mechanical strength.

[0002]

2. Description of the Related Art A corrugated steel pipe armored cable has a conventional structure as shown in FIG. That is, the corrugated steel pipe armored cable 100 has a hollow corrugated steel pipe 101. This is a corrugated steel tube 1 within 01, the cable 102 is accommodated. This cable 102 is formed by twisting a plurality of conductors 104 covered with an insulator 103 such as polyvinyl chloride, filling an outer layer with an inclusion 105 such as a jute for shaping the unevenness of the twisted surface, and forming an outer surface thereof. Is wrapped by a wrapping tape 106, and a sheath 1 made of rubber or synthetic resin is provided outside the wrapping tape 106.
07 is coated. When storing the cable 102 in the corrugated steel pipe 101, the cable 1 is placed between the inner wall surface of the corrugated steel pipe 101 and the outer surface of the cable 102.
02 to prevent rattling in the corrugated steel pipe 101,
An intervening cord 108 such as vinyl is inserted.

[0003] The corrugated steel pipe armored cable 100 whose outer peripheral surface is armored with a corrugated steel pipe as described above is used for direct embedding work or electrical work requiring oil-resistant and chemical-resistant, rat-proof, electromagnetic shielding, etc. for underwater use. A corrugated steel armored cable whose surface is armored with a corrugated steel pipe is used. Since the cable 100 is directly buried in this manner, the corrugated steel pipe armored cable 100 receives moisture from the outside, and the outer surface of the corrugated steel pipe corrodes.

Therefore, conventionally, a corrugated steel pipe armored cable 10 is used.
For No. 0, the outer surface of the corrugated steel pipe is subjected to a moisture-proof treatment.
As a general method of moisture-proofing a corrugated steel pipe, a method of applying a rust-proof paint (etching primer JIS K 5633) 109 to the outer surface of the corrugated steel pipe is adopted as a first method.

As a second method, a method of forming a protective layer 110 by coating the outer surface of a corrugated steel pipe with a synthetic resin of PE (polyethylene) or PVC (polyvinyl chloride) has been adopted.

[0006]

However, in the first conventional method (moisture-proof treatment method of applying a rust-preventive paint), when a corrugated steel pipe is bent or subjected to an impact, the rust-preventive paint layer is formed. Cracks and the like are generated, and there is a problem in that moisture invades from the cracked portions and corrodes the outer surface of the corrugated steel pipe, and the moisture-proof effect is impaired by impact or the like. In the second conventional method (moisture proofing method of covering a synthetic resin protective layer), when the synthetic resin coated on the outer surface of the corrugated steel pipe is damaged by termites, the outer surface of the corrugated steel pipe is damaged. There is a problem in that the surface is exposed and the moisture-proof effect is impaired due to termite damage, such as corrosion of the outer surface of the corrugated steel pipe by receiving moisture from the outside.

Further, the moisture-proof layer is damaged by an external impact or by the harm of termites, rust is generated on the corrugated steel pipe, the mechanical strength is reduced, and the corrugated steel pipe is destroyed. There is a problem that the cable in the inside is damaged by termites, and furthermore, the insulation resistance is reduced due to a decrease in insulation resistance due to moisture absorption, thereby causing a short circuit state.

[0008] The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide an external surface of a corrugated steel pipe for a long period of time even if it is directly buried. An object of the present invention is to provide a corrugated steel pipe armored cable capable of maintaining a high mechanical strength against external impacts on the corrugated steel pipe without losing the moisture-proof effect of the steel pipe.

[0009]

In order to achieve the above object, a corrugated steel pipe armored cable according to the present invention comprises a termite-controlling agent.
Moisture-proof material consisting of asphalt with rubber uniformly added
Into a corrugated steel pipe with a specified inside diameter covered with
It is designed to store and bury directly .

Further, in order to achieve the above object, the corrugated steel pipe armored cable of the present invention has a termitic agent uniformly added thereto.
Moisture-proof material made of rubber asphalt on the outer surface
A synthetic tree obtained by coating and kneading a termiticide on the moisture-proof material
Covered with a protective layer made of oil and formed a double protective layer
The cable is housed in a corrugated steel pipe having a diameter and is directly buried .

[0011]

According to the above construction, even if a corrugated steel pipe is bent or subjected to an impact or the like, unlike the case where the outer surface of the corrugated steel pipe is formed with a rust-preventive paint layer, the corrugated steel pipe is covered with a moisture-proof material, so that it is cracked. This does not cause moisture to be applied to the outer surface of the corrugated steel pipe. In addition, since the termite-control agent is added to the moisture-proof material coated on the outer surface of the corrugated steel pipe, the termites are not damaged by the termites, and the moisture-proof material is damaged by the termites.
Exposed outer surface of the corrugated steel tube Te, resulting in that such as the outer surface of the corrugated steel tube is corroded by receiving moisture from the outside
I will not let you .

[0012]

Embodiments of the present invention will be described below. FIG. 1 shows an embodiment of a corrugated steel pipe armored cable according to the present invention.

In the drawing, reference numeral 1 denotes a corrugated steel pipe armored cable, which has a structure in which the outer peripheral surface is armored with a corrugated steel pipe (still corrugated), for direct embedding work or for underwater use, oil and chemical resistant, rat-proof, electromagnetic shielding. It is used for electrical work that requires such. That is, the corrugated steel pipe armored cable 1 is composed of a corrugated steel pipe 2 having a hollow corrugated steel pipe (still corrugate), and a cable 3 housed in the corrugated steel pipe 2. .

The cable 3 comprises a conductor 4 made of copper or a copper alloy, and a plurality of electric wires coated with an insulator 5 made of a synthetic resin such as polyvinyl chloride. Is filled with an inclusion 6, such as a jute, for shaping the irregularities, and a wrapping tape 7 is wrapped around its outer surface, and a rubber or synthetic resin sheath 8 is coated on the wrapping tape 7. It is configured.

Reference numeral 9 denotes an intervening cord, which is made of synthetic resin such as vinyl, and is interposed between the inner wall surface of the corrugated steel pipe 2 and the sheath 8 of the cable 3. The intervening cord 9 is for preventing the cable 3 from rattling in the corrugated steel pipe 2 when the cable 3 is stored in the corrugated steel pipe 2.

Reference numeral 10 denotes a moisture-proof material, which is coated on the outer surface of the corrugated steel pipe 2. As the moisture-proof material 10, for example, rubber-containing asphalt is used, and the moisture-proof material 10 is formed by uniformly adding a termiticide to the rubber-containing asphalt. As the termiticide, organic phosphorus compounds such as fenitrothion and carbamate compounds are used. This termiticide addition amount is 0.05% by weight.
１10.0% by weight is suitable, optimally 2.0% by weight
Before and after. The use of the moisture-proof material 10 itself has a moisture-proof effect, has an effect of protecting against mechanical strength such as bending and impact, and does not generate cracks as compared with rust-proof paint for a long period of time. Thus, the moisture-proof effect can be maintained. Furthermore, by using the moisture-proof material 10, it is possible to prevent the uniformly added organic phosphorus-based compound such as fenitrothion or the like and a carbamate-based compound or the like from preventing exposure of the outer surface of the corrugated steel pipe due to termite damage. It is possible to prevent the outer surface of the corrugated steel pipe from being corroded due to external moisture. Next, a concrete example of the corrugated steel pipe armored cable 1 of the present example will be described in comparison with a comparative example.

Example 1 In this example, 2% by weight of fenitrothion was placed on a corrugated steel pipe.
The coated asphalt / rubber = 1/1 moisture-proof material.

Comparative Example 1 In Comparative Example 1, an anticorrosive paint was applied to the outer surface of a corrugated steel pipe.

Table 1 shows the results of the moisture-proof tests performed on Example 1 and Comparative Example 1.

[0020] In Table 1, in the results of the moisture proof test, x indicates a state where rust is considerably generated, and ○ indicates a state where rust is not generated.

In the moisture-proof test, the corrugated steel pipe armored cable 1 is bent or subjected to an external impact, and is left in a room with high humidity for one week to examine the state of rusting. . The results of the moisture proof test show that in the case of Comparative Example 1 in which the outer surface of the corrugated steel pipe was coated with the rust-preventive paint, cracks occurred in the coating layer coated with the rust-preventive paint due to bending and impact. Rust occurred. On the other hand, in the first embodiment,
Even when the corrugated steel pipe armored cable 1 was bent or subjected to an external impact, no crack was generated in the moisture-proof material, and no rust was generated on the outer surface of the corrugated steel pipe.

FIG. 2 shows another embodiment of a corrugated steel pipe armored cable according to the present invention. This embodiment is different from the embodiment shown in FIG. 1 in that a synthetic resin protective layer obtained by further kneading a termiticide is formed on the moisture-proof material 10 of the embodiment shown in FIG. is there. The other configuration is not different from the embodiment shown in FIG.

That is, reference numeral 11 denotes a protective layer made of synthetic resin, which is formed by extruding and coating the moisture-proof material 10 in two steps when it is extruded and coated. This protective layer 11 made of synthetic resin is, specifically,
An organic phosphorus compound such as fenitrothion and a termiticide such as a carbamate compound are blended in a vinyl chloride resin.

Next, the corrugated steel pipe armored cable 1 of the present embodiment.
Specific examples will be described in comparison with comparative examples.

Example 2 In this example, 2% by weight of fenitrothion was placed on a corrugated steel pipe.
A moisture-proof material of mixed asphalt / rubber = 1/1 is coated, and a soft polyvinyl chloride resin is coated on the moisture-proof material as a protective layer.

Example 3 In this example, 2% by weight of fenitrothion was placed on a corrugated steel pipe.
Is coated with a moisture-proof material of asphalt / rubber = 1/1, on which fenitrothion 2 is added.
In this case, a soft polyvinyl chloride resin in which the weight% is blended is coated as a protective layer.

Comparative Example 2 In Comparative Example 2, a coating layer coated with a rust preventive paint was formed on the outer surface of a corrugated steel pipe, and a soft polyvinyl chloride resin was coated as a protective layer on the coating layer. is there.

Table 2 shows the results of comparison of the moisture proof tests performed on Examples 2 and 3 and Comparative Example 2.

[0029] In Table 2, in the results of the ant bite test, x indicates a state with considerable scratches, Δ indicates a state with slight scratches, and ○ indicates a state without any scratches. In Table 2, in the results of the moisture proof test, x indicates a state where considerable rust is formed, Δ indicates a state where slight rust is formed, and ○ indicates a state where no rust is formed.

In the moisture proof test, the corrugated steel pipe armored cable 1 is bent or subjected to an external impact, and is left in a room with high humidity for one week to examine the state of rusting. . In the ant bite test, the eighth-quarter soil was placed in a water-tank-shaped container, and samples of corrugated steel pipes prepared under the conditions of Examples 1 and 2 and Comparative Example 2 were buried in the soil. Fifteen
0 termites were put in, and left for 2 weeks to examine the damage of each sample.

The results of the moisture-proof and termite-proof tests are shown in the case of Comparative Example 2 in which the outer surface of a corrugated steel pipe was coated with a rust-preventive paint, and a soft polyvinyl chloride resin was coated on this paint layer as a protective layer. The protective layer was eroded by termites, the outer surface of the corrugated steel pipe was exposed, and the coating layer coated with the anticorrosive paint was cracked by bending and impact, and rust was generated on the outer surface of the corrugated steel pipe.

On the other hand, in Example 2, although the outer surface of the protective layer was slightly damaged by termites, the outer surface of the corrugated steel pipe was not exposed. In addition to the moisture-proof effect of the moisture-proof material, which is resistant to bending and external impact, rust did not occur on the outer surface of the corrugated steel pipe.

In Example 3, the termite-controlling agent incorporated in the protective layer did not cause any damage by termites on the protective layer.
The outer surface of the corrugated steel pipe is not exposed, and furthermore, the moisture-proof material of the moisture-proof material, which is resistant to bending and external impact, is added to the corrugated steel pipe armored cable 1, and the outer surface of the corrugated steel pipe is rusted. Did not occur.

[0034]

Since the present invention is configured as described above, the following effects can be obtained.

In the corrugated steel pipe sheathed cable according to the first aspect, the rubber-containing asphalt to which a termiticide is uniformly added is used.
The outer surface is coated with a moisture-proof material,
Cover with synthetic resin protective layer made by kneading agent, double protection
The cable is housed in a corrugated steel pipe
Since it is directly buried, even when buried directly, it is less likely to crack due to bending, impact, etc. compared to the conventional rust-proof coating, the moisture-proof effect is not impaired, and moreover, it is damaged by termites The synergistic effect of the termite and moisture resistance improves the corrosion resistance of the corrugated steel pipe, maintains high mechanical strength, and improves the long-term reliability of the cable.

In the corrugated steel pipe armored cable according to the second aspect, a rubber-containing asphalt to which a termiticide is uniformly added is used.
The outer surface is coated with a moisture-proof material,
Cover with synthetic resin protective layer made by kneading agent, double protection
The cable is housed in a corrugated steel pipe
Since it is designed to be directly buried , the first term protective layer formed on the outermost layer prevents termites from being damaged by termites, and the second level moisture-proof material formed inside the first level protective layer further protects it from damage. The termites are prevented from being damaged by termites and the termite-proof effect is improved. Furthermore, the second-stage moisture-proof material is used to prevent the moisture-proof layer from cracking due to bending and impact, and does not impair the moisture-proof effect. The synergistic effect of the moisture-proof property improves the corrosion resistance of the corrugated steel pipe, maintains high mechanical strength, and improves the long-term reliability of the cable.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a corrugated steel pipe armored cable of the present invention.

FIG. 2 is a sectional view showing another embodiment of the corrugated steel pipe armored cable of the present invention.

FIG. 3 is a sectional view showing a configuration of a conventional corrugated steel pipe armored cable.

[Explanation of symbols]

1 ………………………………………………………………………………………………………………………………………………………………… ……… Corrugated steel pipe 3 ………………………………………… Cable 4 …………………………………………… ………… Conductor 5 …………………………………………………… Insulator 6 ………………………………………………………… ………… Inclusions 7 ………………………………… Holding tape 8 ………………………………… ............ Sheath 9 ... …………………………………………………………………………………………………………… Synthetic resin protective layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01B 7/20-7/28

Claims (2)

(57) [Claims] A rubber-containing asph to which a termiticide is uniformly added.
Within the specified area with the outer surface covered with a moisture-proof material
Corrugated steel pipe armored cable that stores the cable inside the corrugated steel pipe of diameter and buries it directly . 2. A rubber-containing asph to which a termiticide is uniformly added.
The outer surface is coated with a moisture-proof material made of
Covered with a synthetic resin protective layer made by kneading termites
Into a corrugated steel pipe with a predetermined inner diameter formed with a double protective layer.
Corrugated steel pipe armored cable for storing and directly burying cables.