RU21255U1 - THERMAL-Shrinkable KIT FOR MOUNTING CABLE COUPLINGS - Google Patents

Description

Heat shrink kit for mounting cable glands.

The utility model relates to industrial fields, and more specifically, to the field of electrical work when creating connecting cable heat-shrinkable sleeves containing an external thick-walled tubular electrical insulating layer and an inner layer for leveling the electric field strength.

A heat-shrinkable tube for splicing a telephone cable is known, inside of which there is a second tube made of fusible or heat-softening adhesive material, and a heat barrier in the form of a tubular net is created between these tubular elements (see G B application No. 1603298 IPC Н 02615/18, 1981 g.).

The disadvantage of this solution is that the inner tubular elements used to seal the cable conductors are not designed to equalize the electric field strength, and as a result, when exposed to medium or high voltage, conditions are created for ionization of the air and accelerated destruction of the insulating layer. The closest analogue is a set of couplings for medium voltage (up to 35 kV), containing a separate internal heat-shrinkable tube for leveling the electric field and an external two-layer tube in which the lower thick-walled layer is electrically insulating and the upper thin-walled layer is heat-shrinkable and serves to compress the inner electrical insulating layer of the connection unit during the installation of the coupling (Prospect of the company Reichem "Energy. Cable fittings, 98/99, p.9).

This solution provides a combination in the cable connector of the inner layer to equalize the electric field and the external insulating layer. The disadvantage of this ruffling is the need for consistent heat shrinkage of the tube first

Authors of a utility model;

Azzen L. 5. Yerman V.O., Voloshin S.V.

KRYMOB ii.O.

Saveliev B.C.

.

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to equalize the tension, and then T} eubki with an insulating layer, which complicates the overall installation of the coupling.

Another drawback of this solution is that when heat-shrinking the outer two-layer tube, the compressive effect of the upper heat-shrinkable thin-walled layer may not be sufficient to compress the lower thick-walled layer and, as a result, compress the entire joint assembly.

The problem solved by the utility model is to facilitate the process of mounting the coupling and increase the degree of compression of the connection node.

The problem is solved due to the fact that in the heat-shrinkable kit for mounting cable connectors on medium and high voltage, containing an external thick-walled tubular

an electric insulating layer and an inner layer for leveling the electric field, the entire outer layer is heat-shrinkable, and the inner layer is made in the form of a thin-walled heat-flowing tube, firmly connected to the inner surface of the outer layer.

In addition, the inner layer has a length within 70-90% of the length of the outer layer and is located symmetrically relative to it.

The technical result of using the proposed solution is as follows. The proposed connection of the inner layer to equalize the electric field with the outer layer allows thermal shrinkage of both layers in the stage, which greatly facilitates the entire process of mounting the coupling. At the same time, a strong connection of the layers eliminates their displacement among themselves during installation work. The implementation of the inner layer of thermo-fluid material, which also has the necessary electrical properties, ensures the spreading of the inner layer during shrinkage of the outer layer and, as a result, good filling of voids and smoothing of sharp protrusions at the junction of the cable conductors, which contributes to the equalization of the electric field strength. In addition, this contributes to the fact that the entire external thick-walled electrical insulating layer is heat-shrinkable and when it is shrinkable, good compression of the evil compound is ensured. In addition, a positive technical result is complemented by a shorter length and a symmetrical arrangement of the inner layer with respect to the outer layer. Due to this, when growing with Nin, the inner layer is evenly distributed over the entire inner surface of the outer layer. Experimentally set (zpena

- 3 optimal relative length of the inner layer c. within 70-90% of the length of the outer layer. When this limit is shorter than the value of 70%, the distribution of the inner layer over the entire inner surface of the outer layer is not ensured, and if this limit is increased above 90%, the inner layer can leak outside the outer layer, which can disrupt the general design of the connection node.

The utility model is illustrated by the drawings in Fig. 1.2.

Pa Fig. 1 shows the proposed kit in its original state, where:

1- external insulating heat-shrinkable layer;

2- inner layer for leveling tension

electric field.

Pa Fig. 2 shows the proposed kit after heat shrinkage, where:

1,2 - designations according to fig L.

3 - layout of the connection node.

Example 1. To connect two pieces of cable with a cross-section of 70 sq. Mm for an operating voltage of 10 kV using a coupling, a heat-shrinkable two-layer tubular set is preliminarily made, in which the entire external electrical insulating layer is preliminarily expanded by a tubular billet made of material suitable for heat shrinkage, for example , from a composition based on polyethylene and elastomeric (based on ethylene-propylene rubber) components. The inner layer is made of thermofluid material in the form of a thin-walled tube, which is symmetrically firmly connected to the inner surface of the outer layer, for example, by means of radial pressure from the inside with slight heating. The values of the electrical characteristics of the material of the inner layer (dielectric constant, insulation resistance, electric strength) are in the required ratio with the values of the similar characteristics of the outer layer, in order to ensure effective equalization of the electric field when exposed to electric voltage.

The resulting set has the following geometric dimensions, respectively, of the outer and inner layers (mm): length 185 and 150, inner diameter 45 and 43.5, wall thickness 4 and 0.75.

The kit is put on at one end of the cables to be connected and retracted from the connection node. After connecting the cable cores by known methods, for example, using a connecting sleeve, the kit is pushed onto the connection node with a symmetrical

 3.

location. After that, using well-known methods, for example, using a gas burner, the set is shrunk. Then on top is a protective coating.

The resulting coupler passed the tests successively with a constant voltage of 60 kV for 10 min, an alternating voltage of 50 Hz of 20 and 30 kV for 10 min and 40 kV for 4 hours.

 4 Formula

Claims (2)

1. A heat-shrinkable kit for mounting cable connectors on medium and high voltage, containing an external thick-walled tubular electrical insulating layer and an inner layer for leveling the electric field, characterized in that the entire outer layer is heat-shrinkable, and the inner layer is made in the form of a thin-walled thermofluid tube, firmly connected to the inner surface of the outer layer. 2. Heat-shrinkable kit according to claim 1, characterized in that the inner layer has a length within 70-90% of the length of the outer layer and is located symmetrically relative to it.