JPS5864709A - High pressure refractory wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in high-voltage fireproof electric wires for emergency power sources.

Conventional high-voltage fire-resistant electric wires have a structure in which Mica tape is wrapped as a fire-resistant layer directly above the conductor, and on top of that, a cross-linked polyethylene insulation layer, an external semiconductive layer, a mild steel tape barrier layer, and a plasti-thickness layer are applied. It is something that you have.

Electric wires with this structure have a fireproof layer made by winding a piece of glass laminated mica tape containing countless microscopic voids in the insulating layer with the highest electrical stress □ on the conductor, so deterioration of the insulating layer due to corona discharge is prevented. more likely to occur. In addition, during the manufacturing process of the electric wire and after it is laid (moisture easily enters the layer here, there is a risk of water tree formation as a result), which poses a problem to the long-term stability of the high-voltage electric line.

By the way, the present inventors have found that when a layer of cellulose fibers such as corpse air insulating paper is applied to the outside of a conventionally used high-voltage crosslinked polyethylene insulated wire, the cellulose fiber layer Even if it is directly heated with a flame, it is unexpected (
Due to its slow combustion rate and excellent heat insulation properties, we unexpectedly obtained new knowledge that it passed the 840°C fire resistance test 1 as announced by the Fire and Disaster Management Agency, and completed the invention as claimed in the claims. I ended up doing it.

The electric wire structure of the present invention will be explained in detail below with reference to the drawings.

The attached figure shows a cross-sectional view of an embodiment of the present invention (5-core structure), in which a conductor 1, an inner semiconducting layer 2, a cross-linked polyethylene insulating layer 3, an outer semiconducting layer 4, and a mild steel tape wound around it. Three insulated wire cores 6 consisting of a shielding layer 5, jute interposed 7
A heat insulating layer 8 formed by winding a cellulose fiber tape on top of the twisted cellulose fiber tape, and a wound layer of asbestos paper double-sided planutic film laminated tape to prevent the winding of the cellulose fiber tape from unraveling. It has a structure including a scratch prevention layer 9 and a plastic sheath 10.

The heat insulating layer 8 may be an aggregate of cellulose fibers such as wood pulp, but from the viewpoint of ease of manufacturing the cable, it is preferably formed by winding a cellulose fiber paper tape. As the cellulose fiber paper tape, ordinary electrically insulating paper tape or other paper tape may be used. The paper tape may be crepe-treated or non-crepe-treated, but crepe-treated paper, so-called crepe paper, is particularly preferred in the present invention because of its superior fire-retardant properties. It also has the effect of improving the □flexibility of the cable under normal conditions. The appropriate paper tape to be used has a thickness of about 40 .mu.rrL to 300 .mu.rIL and a paper width of about 10 to 60 gourds. In addition,
The thickness of the heat insulating layer 8 is preferably at least about 5fi, particularly preferably in the range of 6wl1 to 20+w.

Prevention of unraveling/i19 means that when the heat insulating layer 8 is formed by winding paper tape, the outermost tape of the insulating layer will come apart when the heat insulating layer 8 is ignited and burned during a fire. The combustion rate varies greatly depending on whether or not it spreads, and if no dispersion occurs, the combustion rate will be slow. Thus, the anti-unraveling layer 9 plays an effective role in preventing the paper tape from unraveling and thus maintaining the heat insulating properties of the heat insulating layer 8 over a long period of time.

As the constituent material of the anti-unraveling layer 9, asbestos and a tape made of paper and planutic film laminated together are used. The tape may have a thickness of 01 to 0.5 wm.
Polyethylene or polypropylene with a thickness of about 5 to 50 μm on asbestos paper.

It is possible to use an olefin-based polymer such as polyester, polyester such as polyethylene terephthalate, or a polyamide resin such as nylon, bonded together with a rubber-based adhesive, a hot-melt adhesive, or the like.

By providing an anti-unraveling layer on the outside of the above-mentioned insulation layer, damage caused by the insulation layer unraveling in the event of a fire is minimized,
It is expected to have a function that further improves the insulation effect, and the thickness varies depending on the type and thickness of the insulation layer, but it is approximately 5 to 6 meters thick.
It may be at least 2 to 4III+11.

The plastic sheath 10 may be made of the same sheath material used in ordinary high-voltage crosslinked polyethylene insulated wires, such as polyvinyl chloride or polyethylene, and is preferably a 111I smokable sheath material.

Further, the sea 7 layer 10 is made of foamable fireproofing materials, such as foamable fireproofing compositions disclosed in Japanese Patent Publication No. 55-24215 and Japanese Patent Application Laid-open No. 54-10552, various foamable fireproofing paints, or the like. It may be composed of a tape or tape made of inorganic or organic fibers coated or impregnated with it, or it may have a two-layer structure in which a layer of the above-mentioned foamable fireproof material is applied on a normal sheath. There may be.

When a foamable fireproof material is used, in the event of a fire, the material foams to form a carbonized layer and exhibits a heat insulating effect, so there is an advantage that the heat insulating layer inside can be made thinner.

The great industrial advantage of the present invention is that it can be made fireproof by using an inexpensive material called cellulose fiber, and by simply applying it to the outside of high-voltage cross-linked polyethylene insulated wire, which has been traditionally manufactured and used. be.

Therefore, there is no problem with the stability of the cable's transmission force during normal use, unlike conventional high-voltage fire-resistant wires in which a fire-resistant layer is applied to the conductor layer.

The attached table shows the structure and remarkable effects of the cable according to the embodiment of the present invention.

The present invention includes a single-core or multi-core cable of A3KV or higher, which has an insulating layer made of polyethylene, crosslinked polyethylene, or an insulating material mainly composed of polyethylene or polyethylene, and includes other rubbers and plastics.

[Brief explanation of the drawing]

The attached figure is a sectional view of an embodiment of the present invention, in which 6 is a normal crosslinked polyethylene insulated cable, 7 is an intervening layer, 8 is a heat insulating layer, 9 is an anti-unraveling layer, and 10 is a sheath. Patent applicant: Dainichi Nippon Electric Cable Co., Ltd. Representative Director: Yukio Aoyama

Claims (1)

[Claims] On the conductor, an inner semiconducting layer, an insulating layer mainly made of polyethylene, an outer semiconducting layer, and a shielding layer wrapped with copper tape are provided on an insulated wire core, or on the outside of a strand of multiple insulated wire cores. A high-voltage fire-resistant IT line characterized by comprising a heat insulating layer made of cellulose fibers, an anti-unraveling layer and a loose layer made of asbestos paper double-sided plastic film laminated tape windings.