RU2371796C1 - Method of producing electric insulator and electric insulator produced thereby - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: proposed method comprises producing bearing core by applying glass fiber strand on terminations, twisting aforesaid strands, curing of binder and applying coating. Bearing core is made of continuous glass fiber strand. Note that additional coils of strands are laid around terminations. Note also that aforesaid additional coils of one termination are connected with extending additional coils laid around the other termination with the help of fiber from shrinking material. Then bearing core and terminations compacted by shrinking-material band and impregnated by polymer binder. Lavsan, polyether can be used as aforesaid binder. Note that bearing core cross section area equals that of glass fiber layer laid around eye-type termination.

EFFECT: higher strength.

5 cl, 1 dwg

Description

The invention relates to electrical engineering, and in particular to methods of manufacturing electrical insulators from high-strength composite materials, for example fiberglass, which can be used in overhead power lines, substations, contact electric transport networks, etc.

The analysis of the prior art by the applicant has shown that methods for manufacturing electrical insulators from high-strength composite materials and insulators obtained by these methods are known in the art (RF patents Nos. 2119689, 2233492, 2256252, US patent No. 4958049, etc.).

Closest to the claimed technical solution is an electrical insulator and the method of its manufacture according to the patent of the Russian Federation No. 21118005.

Known electrical insulator contains a supporting element made of fiberglass impregnated with a binder, two terminals and a sheath. In this case, the supporting element is made in the form of a two-layer bundle twisted from a continuous strand of fiberglass laid around the tip, and the inner and outer layers are twisted in the opposite direction of each other.

A method of manufacturing this electrical insulator includes impregnating a strand of unidirectional fiberglass with a binder, forming a support member, curing the binder, and coating. The formation of the supporting element is carried out by laying around the terminator impregnated with a binder of a continuous strand of fiberglass, sequentially forming the inner and outer layers of the bundle of the desired length and thickness. Then, the inner layer is twisted, the outer layer is superimposed on it and the layers are twisted together in the opposite direction, followed by axial extension of the supporting element.

The known method does not allow to achieve high strength characteristics of the insulator, because its implementation leads to unequal construction, since the number of strands forming a supporting rod is twice the number of strands laid around each of the terminal. Accordingly, the cross-sectional area of the formed support rod will be twice as large as the cross-sectional area of the fiberglass layer laid around each of the terminators, i.e. the mechanical strength of the fiberglass laid around the terminators is at least two times less than the mechanical strength of the supporting fiberglass rod, which reduces the strength of the structure as a whole.

In addition, voids form when laying fiberglass, as a result of which the finished fiberglass is heterogeneous, which reduces the dielectric strength.

It should also be noted that in the known method of manufacturing an electrical insulator, the formation of the supporting element is carried out by laying a continuous strand of fiberglass that has already been pre-impregnated with a binder, which does not allow this to be done qualitatively, and the laying process itself becomes a laborious and "dirty" process, which reduces its manufacturability.

The objective of the present invention is to develop a method that allows to achieve high strength characteristics of an electrical insulator.

The technical result achieved by using the invention, lies in the manufacture of the claimed method of equal strength design.

The problem is solved in that the method of manufacturing an electrical insulator includes the formation of a supporting rod by laying a continuous strand of fiberglass around the terminators, the joint twisting of the strands of fiberglass, curing the binder and coating. The formation of the supporting rod is carried out by a continuous strand of dry fiberglass. At that, the required number of additional turns of fiberglass strands are laid around the terminators, which protrude beyond the terminators from the side of the formed supporting rod by a distance equal to at least two diameters of the rod. Moreover, the protruding additional turns of fiberglass strands, laid around one terminal, tighten with the protruding additional turns of fiberglass strands, laid around another terminal, with a fiber of heat-shrinkable material. Next, the supporting rod and the terminators are sealed with a tape of heat-shrinkable material and impregnated with fiberglass polymer binder.

Wherein:

- impregnation of fiberglass with a polymer binder is carried out by a vacuum-discharge method;

- as a heat-shrinkable material use lavsan, polyester.

The problem is also solved by the fact that the electrical insulator contains a supporting rod made of fiberglass, two ends, around each of which a layer of fiberglass is laid, and a shell. Moreover, the carrier rod and the terminators are sealed with a tape of heat-shrinkable material, and the cross-sectional area of the carrier rod is equal to the cross-sectional area of the fiberglass layer laid around each of the terminators.

Wherein:

- terminators made in the form of thimbles.

The claimed method of manufacturing an electrical insulator differs from the known one by the formation of the carrier rod, the sealing of the carrier rod and the terminators with a tape of heat-shrinkable material, and the fact that the fiberglass is impregnated with a polymer binder after the formation of the structure.

The formation of the supporting rod is carried out by laying a continuous strand of fiberglass around the terminal. Moreover, around the terminators, the required number of additional turns of fiberglass strands is laid. This is done to ensure the same number of strands forming the supporting rod, and the number of strands laid around each of the terminal. Then the cross-sectional area of the formed supporting rod will be equal to the cross-sectional area of the layer of strands of fiberglass laid around each of the terminators. But in order for the design to turn out to be equally strong, additional turns of fiberglass strands must be made to work. Therefore, they are not closely laid around the terminators, but from the side of the formed supporting rod they protrude beyond the terminators at a distance equal to at least two diameters of the rod. This allows, pulling the protruding additional turns of the strand, laid around one terminal, with the protruding additional turns of the strand, laid around the other terminal, with a fiber of heat-shrinkable material during subsequent joint twisting of the strands, pull them into the supporting rod and make it “work”. This embodiment of the method allows to obtain equal strength construction, which increases the mechanical strength of the insulator during its operation. The distance over which additional turns of the strand protrude cannot be less than two diameters of the formed rod, because this will not allow reliably tightening the additional turns of the strand into the rod, which can lead to rupture of part of the strands and, consequently, to a decrease in the mechanical strength of the insulator.

The sealing of the supporting rod and the terminators with a tape of heat-shrinkable material makes fiberglass homogeneous, without voids, which increases the dielectric strength.

The formation of the supporting rod by a continuous strand of dry fiberglass makes the formation process better, less time consuming and "not dirty".

In the inventive electrical insulator, the supporting rod and the terminators are sealed with a tape of heat-shrinkable material. This, as mentioned above, makes fiberglass uniform, which increases the dielectric strength of the insulator during its operation.

In the inventive electrical insulator, the cross-sectional area of the bearing rod is equal to the cross-sectional area of fiberglass laid around the terminal. This ensures equal strength of both the supporting rod and the terminators, which increases the mechanical strength and, as a result, the reliability of the insulator during its operation.

The drawing shows an electrical insulator - a General view, which contains:

1 - bearing rod

2 - terminators

3 - shell

4 - heat shrink tape

5 - heat-shrink fiber

6 - additional turns of the strand

In more detail, the proposed technical solution is described using an example of a specific implementation, not limiting the invention.

At a given distance, terminators are installed around which a continuous strand of dry fiberglass is laid. Next, the required number of additional strands of strands are laid around the terminators until the same number of strands forming the supporting rod and the number of strands laid around the terminators are obtained (for example, if one O-shaped revolution of a continuous fiberglass strand is laid around the terminators, then one additional one is placed around each of the terminators a strand of fiberglass). Additional turns of fiberglass strands are laid in such a way that they protrude beyond the ends at the required distance from the side of the formed supporting rod. Next, the protruding additional turns of the strand, laid around one terminal, are pulled together with the protruding additional turns of the strand, laid around another terminal, with a fiber of heat-shrinkable material, after which the fiber strands are twisted together. Then, the supporting rod and the terminators are sealed with a tape of heat-shrinkable material. The structure formed in this way is placed in a container for impregnating fiberglass with a polymer binder, which is carried out by the vacuum-injection method, cyclically applying vacuum and pressure. Next, curing the binder and applying a protective coating. As the sheath material, silicone rubber may be used.

The electrical insulator made by the claimed method, having a size of 250 mm and a cross section of 10 mm, has an electric strength of 50 kV / cm and a tensile strength (mechanical strength) of 80 kN, which is twice (in terms of mechanical strength) greater than the known electrical insulator.

Thus, the use of the proposed method allows to achieve the following technical result:

- to provide high strength characteristics of the electrical insulator due to the creation of equal strength design.

A method of manufacturing an electrical insulator is simple, technological, does not require the development of special equipment, and can be carried out at any production of fiberglass products.

An electrical insulator made by the claimed method is intended for use in overhead power lines, substations, contact electric transport networks, etc.

Claims (5)

1. A method of manufacturing an electrical insulator, including forming a supporting rod by laying a continuous strand of fiberglass around the terminators, jointly twisting the strands of fiberglass, curing the binder and applying a sheath, characterized in that the formation of the supporting rod is carried out by a continuous strand of dry fiberglass, while the required amount is laid around the terminators additional turns of fiberglass strands that protrude beyond the terminators from the side of the formed support rod I am at a distance equal to at least two diameters of the rod, then the protruding additional turns of fiberglass strands laid around one terminal are pulled together with the protruding additional turns of fiberglass strands arranged around the other terminal, with a fiber of heat-shrinkable material, then the bearing rod and the terminators are sealed with a heat-shrinkable tape material and impregnate fiberglass with a polymer binder. 2. A method of manufacturing an electrical insulator according to claim 1, characterized in that the glass fiber is impregnated with a polymer binder by a vacuum-discharge method. 3. A method of manufacturing an electrical insulator according to claim 1, characterized in that lavsan and polyester are used as heat-shrink material. 4. An electrical insulator comprising a carrier rod made of fiberglass, two terminators, a fiberglass layer around each of which is laid, and a sheath, characterized in that the carrier rod and terminators are sealed with a tape of heat-shrinkable material, while the cross-sectional area of the carrier rod is equal to the area a cross section of a fiberglass layer laid around each of the terminators. 5. The electrical insulator according to claim 4, characterized in that the terminators are made in the form of thimbles.