JPS6213295Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to preventing water running in rubber or plastic insulated power cables.

Traditionally, when water begins to enter the cable from a damaged sheath or terminal part of a power cable, water travels in the longitudinal direction of the cable due to capillary action, causing corrosion of the shielding layer and moisture absorption deterioration of the insulator. This is the cause of this and eventually leads to dielectric breakdown.

In order to prevent this phenomenon, it has been proposed to use extruded inclusions or a so-called anti-water running tape made by coating a predetermined cloth tape with a hygroscopic material such as polyethylene oxide, but these have not been effective to some extent. It's there, but it's still far from perfect. In particular, when a copper tape is used as the material of the shielding layer, water running is likely to occur on the inner and outer surfaces of the shielding layer, or on the contact surface between the twisted inclusions and the holding tape layer that is in contact with the inclusions. A possible reason for this is that conventional semiconductive or insulating tapes are mainly composed of rubber-impregnated or rubberized materials and are vulcanized, resulting in a lack of flexibility on the tape surface. One of the reasons for this is the lack of contact pressure.

SUMMARY OF THE INVENTION The object of the present invention is to provide a rubber or plastic insulated power cable which eliminates the drawbacks of the prior art described above, improves the ability to prevent water from running inside the cable, and has stable insulation properties.

That is, the gist of the present invention is to provide adhesive layers on both sides of a semiconductive or insulating tape to prevent water from running on the contact surface between the tape and another object.

The present invention will be explained below based on embodiments shown in the drawings.

FIG. 1 is a cross-sectional view of a three-core cable, in which the outer periphery of a conductor 1 is covered with an insulator 2, and a semiconductive tape layer 3,
After sequentially applying a shielding layer 4 and a holding tape layer 5 to form a single-core cable, the three cables are twisted together with an inclusion 6, and a holding tape layer 7 and a sheath 8 are applied to the outer periphery to form a completed three-core cable. .

The present invention is based on the semiconductive tape layer 3 in the above process.
In addition, the holding tape layers 5 and 7 are tape wrapping layers made of an adhesive material such as unvulcanized butyl rubber on both sides, and 3 is a base material cloth tape or plastic tape with conductive on both sides. A double-sided adhesive semiconductive tape made by applying carbon-containing unvulcanized butyl rubber is applied to 5 and 7, and unvulcanized butyl rubber is applied to both sides of the cloth tape or plastic tape that serves as the base material. This uses double-sided adhesive insulating tape.

In addition, although the case of a 3-core cable was adopted in the embodiment, it is fully applicable to multi-core cables other than 3-core cables, and even single-core cables.

According to the present invention, by providing an adhesive layer on the inner and outer surfaces of the shielding layer and the contact surface between the holding tape layer and the twisted inclusions, where water runs easily in a rubber or plastic insulated power cable, these It is possible to increase the contact pressure and adhesion of the contact surface and to greatly increase the water running prevention effect.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an example of a water running prevention type power cable of the present invention. 1: conductor, 2: insulator, 3: double-sided adhesive semiconductive tape layer, 4: shielding layer, 5: double-sided adhesive insulation pressing tape layer, 6: inclusions, 7: double-sided adhesive insulation pressing tape layer, 8: Sheath.

Claims (1)

[Scope of utility model registration request] A single-core cable made by covering the outer periphery of the conductor 1 with an insulator 2, and sequentially applying a semiconductive tape layer 3, a shielding layer 4, and a holding tape layer 5 is twisted together with an inclusion 6, and a holding tape layer 7 is placed on the outer periphery of the single-core cable. In the power cable provided with the sheath 8, the semiconductive tape layer 3 is composed of a wrapped layer of double-sided adhesive semiconductive tape, and the holding tape layers 5 and 7 are composed of a wrapped layer of double-sided adhesive insulating tape. A water running prevention type power cable characterized by comprising: