JPS58181206A - Flexible conduit gas cable - 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 a flexible conduit aerial cable with improved electrical characteristics.

Recently, as shown in FIG.
The divided insulating spacers 13 are installed on the corrugated metal tube 12 at predetermined intervals, and the corrugated metal sheath 14 with the anti-corrosion layer 15 is placed on the outside. 16 has been proposed. 1 In a flexible conduit aerial cable having such a structure, there is an insulating gas 1 with a dielectric constant in the corrugated metal tube 12.
6 (permittivity ε-1) and insulation subeder 13 with a large dielectric constant (permittivity ε greater than 1) coexist, the four potential lines at the insulating spacer attachment part are as shown in Figure 1 (Ha). ), according to the static magnetic field theory, the gas is concentrated in the gas space having a low dielectric constant, that is, in the space α between the inner peripheral surface of the insulating spacer 1j and the valley of the corrugated metal tube 12. The concentration of this electric field increases as the dielectric constant of the insulating spacer 13 shown in FIG. Insulating spacer 13 attached in contact with the peak
The greatest electric field is concentrated in the space between the inner circumferential surface of the corrugated metal tube 12 and the trough α of the corrugated metal tube 12, resulting in dielectric breakdown at low forming pressures.

The present invention aims to eliminate such drawbacks and provide a flexible conduit aerial cable having excellent electrical properties.Examples of the present invention will now be described in detail.

43 in Figure 2, 1 is a #M4 twisted wire conductor, 2 is a corrugated metal tube housing the stranded conductor 1 for ++ construction flexibility, and 3 is a split insulating spacer, and this spacer is shown in Figure 2 (B). As shown in the figure, it is a two-part insulating space 9 formed by integrally connecting an inner rim part 3α and an outer rim part 3b with a plurality of leg rods 3C arranged at equal intervals.

4 is a corrugated metal sheath covered on the outside of the corrugated metal tube 2 to which the insulating smoother 3 is attached at predetermined intervals; Insulating gas 6 is sealed. FIG. 3 shows another embodiment of the present invention in which a reinforcing member 3d is attached to the inner circumferential surface of the outer spacer of the insulating spacer 3 in order to improve the mechanical strength, and FIG. A plurality of leg rods 3 are protruded from the outer peripheral surface of the corrugated metal tube 2, and the leg rods 3e are installed in close contact with the trough α of the corrugated metal tube 2 to prevent the insulation from breaking from the attachment part of the insulating spacer 2. Another embodiment of the present invention is shown in which this problem is prevented.

As described above, the present invention is a corrugated metal that houses the stranded conductor 1, O, inner 1, 1 part 34 and outer +) A93A,! An external corrugated metal sheath 4 filled with insulating gas is formed by a two-split insulating spacer 3 formed by integrally connecting: with a plurality of leg rods 3C.
By supporting coaxially inside the insulating spacer 3, the proportion of the gas space occupied by the insulating spacer 3 becomes very large, and the space between the leg rods 3C of the insulating spacer 3 attached to the crest of the internal corrugated metal tube 20 is considerably large. fr where gas space A exists
Female spacer 33.11. Back. Yo state, oh. □It is possible to effectively prevent the electric field from concentrating in the alo space, and as shown in Figure 2 (c), the equipotential lines around the corrugated metal tube at the insulating spacer mounting area are not disturbed and the electric field is concentrated. A flexible conduit aerial cable is obtained which has no risk of dielectric breakdown and has electrical properties that are stable over time. Note that the shape of the internal flexible metal tube 2 in the present invention may be a type in which peaks and valleys are alternately continuous on the same circumference, or a spiral type corrugated metal tube. Of course.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a conventional flexible conduit aerial cable, Fig. 2 is an explanatory diagram showing an embodiment of the present invention, and Figs. 3 and 4 are explanatory diagrams of an insulating spacer in the present invention. 0 1: Stranded conductor 2 = Corrugated metal tube 3: Insulating spacer 4; Corrugated metal sheath b: Corrosion protection layer 6
: Insulating gas

Claims (1)

[Claims] An internal corrugated metal tube containing a stranded conductor and an external corrugated metal sheath are coaxially connected using an insulating spacer, which is formed by integrally connecting the inner and outer lino parts at predetermined intervals with multiple leg rods. 7 lexiple conduit aerial cable 0 characterized by being supported by a metal sheath with external corrugations and insulating gas sealed in an external corrugated metal sheath.