JPH0569820U - Running water prevention cable - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent water running in the longitudinal direction of a cable having a metal sheath such as a corrugated aluminum sheath. [Constitution] The cable core 1 is coated with a heat-expandable material,
The corrugated aluminum sheath 3 and the anticorrosion layer 4 made of vinyl chloride resin or the like are extrusion-coated on the outer side thereof in order, and the heat-expandable material is expanded by the heat at the time of extrusion, and the thermal expansion layer 2 causes the water running path. The gap between the cable core 1 and the corrugated aluminum sheath 3 is filled.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a running water prevention cable that prevents running water in the longitudinal direction of the cable.

[0002]

[Prior Art]

 Conventionally, in rubber / plastic insulated power cables such as CV cables (crosslinked polyethylene insulated cables), a metal sheath such as lead or aluminum is provided on the outer periphery of the cable core to prevent water from entering the cable core. ing.

Further, in such a cable, conventionally, a water absorbent tape is wound as a seat of a shielding layer or a holding tape to prevent water running in the longitudinal direction of the cable. The water-absorbent tape absorbs tens to hundreds of times its own weight against the intrusion of water from the outside and swells by swelling to prevent water running in the longitudinal direction.

[0004]

[Problems to be solved by the device]

 However, such a water-absorbent tape can improve the water-running prevention effect relatively easily in a cable having a small gap between the cable core and the metal sheath, but in a cable having a large gap (for a CV cable, for example, it is usually For 220kV and above), there was a problem that it was not possible to achieve a sufficient running water prevention effect.

The present invention has been made in order to solve such a problem. Even if the cable has a metal sheath with a large gap between the cable core and the cable core, such as a corrugated aluminum sheath, It is an object of the present invention to provide a cable having an excellent effect of preventing running water that can completely prevent running water in the longitudinal direction.

[0006]

[Means for Solving the Problems]

 The water running prevention cable of the present invention is characterized in that a thermal expansion layer of a thermally expansive material is provided between the cable core and the metal sheath coated on the outer periphery thereof to fill the gap. ..

In the present invention, the heat-expandable material is preferably one that expands at a relatively low temperature and has a high volume expansion coefficient. Furthermore, due to the characteristics of the cable, it has excellent fire resistance, flame retardancy, and heat resistance. The thing is more preferable. Examples of such materials include Fire Barrier (commercial name of Sumitomo 3M), which is a composite material of ceramics and flame-retardant rubber. By the way, this fire barrier is a thermally expansive composite material with an expansion starting temperature of 120 ° C and a volume expansion coefficient of 5 to 11 times (8 times on average) and excellent fire resistance, flame retardancy, and heat resistance. It is provided in the form of.

In order to provide a thermal expansion layer made of such a material, the thermal expansion material as described above is coated on the outer periphery of the cable core, for example, in the case of a fire barrier film, by winding or longitudinal alignment, and a metal is used. After providing the sheath, it may be heated and expanded. When the metal sheath is coated by extrusion, it may be heated and expanded at the same time by the heat at that time. Further, when the metal sheath is extrusion-coated with an anticorrosion layer such as a vinyl chloride resin, the heat may be used.

It should be noted that the coating of the heat-expandable material may be performed so that the gap between the cable core and the metal sheath is finally filled by the heat expansion, and therefore it is not necessarily applied to the entire outer periphery of the cable core. No need. Further, the thickness and the like are appropriately determined depending on the kind of the heat-expandable material and the gap to be filled.

[0010]

[Action]

 In the run-off prevention cable of the present invention, the gap between the cable core and the metal sheath is filled with the heat expansion layer of the heat-expandable material, so that the cable core and the metal sheath such as the corrugated aluminum sheath cable are connected. Even if the gap between them is very large, running water in the longitudinal direction can be completely prevented.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical cross-sectional view showing an embodiment of the running water prevention cable of the present invention.

In the figure, reference numeral 1 denotes a cable core in which an inner semiconductive layer, an insulator, and an outer semiconductive layer are sequentially provided on a conductor. On such a cable core 1, a corrugated aluminum sheath 3 is provided via a thermal expansion layer 2 made of a thermally expandable material such as a fire barrier, and further thereon, an anticorrosion layer 4 made of vinyl chloride resin or the like. Is provided. The gap between the cable core 1 and the corrugated aluminum sheath 3 is completely filled with the thermal expansion layer 2.

This cable is manufactured as follows.

First, as shown in FIG. 2 (a), heat is applied to the entire outer circumference of the cable core 1 by winding or vertically attaching a film-shaped material or applying a putty-shaped material. The expandable material 5 is coated, for example with a thickness of 1.5 to 2.5 mm.

Next, as shown in FIG. 3, for example, a wave with a distance from the cable core 1 of about 1.5 mm at the valley portion and about 4 to 6 mm at the ridge portion is provided on the outside of the coating of the thermally expandable material 5. The aluminum sheath 3 is extrusion-coated at a temperature of about 500 ° C., and then a molten vinyl chloride resin or the like is extruded thereon to form the anticorrosion layer 4. At the same time, the heat generated when the corrugated aluminum sheath 3 and the vinyl chloride resin are extruded at the same time expands the heat-expandable material 5, so that the gap between the cable core 1 and the corrugated aluminum sheath 3 is reduced. The anti-running cable having the above structure completely filled with the thermal expansion layer 2 is obtained.

The running water prevention cable thus obtained has the gap between the cable core 1 and the corrugated aluminum sheath 3 which is the running path completely filled with the thermal expansion layer 2, so that the cable It is possible to completely prevent running water in the longitudinal direction.

Further, the thermal resistance of the thermally expandable material after expansion and the surface heat radiation resistance of the cable core 1 are almost equal, but the thermal resistance is reduced to 30% by suppressing the thermal expansion coefficient to about 50%. It can be reduced to some extent.

Furthermore, if a fire-resistant or flame-retardant material is used as the heat-expandable material 5, the disaster prevention effect at the time of a ground fault can be improved.

Although the above embodiment is an example in which the entire outer circumference of the cable core 1 is covered with the heat-expandable material 5, it may be partially covered. For example, as shown in FIG. The example shown in FIG. That is, it is possible to coat at intervals in the cable longitudinal direction or the circumferential direction, or to coat in a spiral shape.

Further, in the example of FIG. 4, the water-absorbent tape 6 is wound around the non-covered portion of the heat-expandable material 5, but in the present invention, the heat-expandable material and the water-absorbent tape are thus combined. They can be used together, and a two-layer structure in which a water-absorbent tape winding layer is provided on the cable core 1 and a thermal expansion layer 2 of a thermally expandable material is provided thereon may be used.

[0022]

[Effect of the device]

 As described above, in the water runout prevention cable of the present invention, the gap between the cable core and the metal sheath, which serves as the water intrusion and water running path from the outside, is filled with the thermal expansion layer of the thermally expandable material. Therefore, it has excellent water running prevention properties.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a water running prevention cable of the present invention.

FIG. 2 is a diagram illustrating a manufacturing method of the embodiment shown in FIG.

FIG. 3 is a side view showing an example of a manner of coating the outer circumference of the cable core with a thermally expandable material.

FIG. 4 is a side view showing another example of a manner of coating the outer circumference of the cable core with a heat-expandable material.

FIG. 5 is a side view showing another example of a manner of coating the outer circumference of the cable core with a heat-expandable material.

[Explanation of symbols]

 1 ... Cable core 2 ... Thermal expansion layer of thermal expansion material 3 ... Corrugated aluminum sheath 4 ... Anticorrosion layer 5 ... Thermal expansion material

Claims (1)

[Scope of utility model registration request] 1. A water running prevention cable characterized in that a thermal expansion layer of a thermally expandable material is provided between a cable core and a metal sheath coated on the outer periphery of the cable core to fill the gap.