EP2117013A1

EP2117013A1 - A hang-type composite insulator

Info

Publication number: EP2117013A1
Application number: EP07845658A
Authority: EP
Inventors: Xuewen Xie
Original assignee: Zhuzhou Times New Material Technology Co Ltd
Current assignee: Zhuzhou Times New Material Technology Co Ltd
Priority date: 2006-11-24
Filing date: 2007-11-20
Publication date: 2009-11-11
Anticipated expiration: 2027-11-20
Also published as: WO2008061446A1; EP2117013B1; CN1963960A; CN100481276C; EP2117013A4

Abstract

Disclosed is a hang-type composite insulator, which comprises a mandrel (1), an umbrella-skirt sheath (2) outside of the mandrel and end assemblies (3) provided at the two ends of the mandrel, wherein orientated glass fiber is used as reinforced body material for mandrel, each end assembly includes a sleeve (4) with a taper hole, a conical body (5) for inserting any end of the mandrel, a locking unit (6) and a connection member (7), the reinforced body material and the structure of the end assemblies improve the plasticity and strength of the insulator.

Description

FIELD OF THE INVENTION

The invention relates to a composite insulator for use in electrical lines or electrified railways, in particular, to a hang-type composite insulator.

BACKGROUND

An insulator is typically made of insulator material with extremely high electrical resistance. The insulator serves to space out conductors having different electrical potentials apart and allows no electrical current flowing therebetween so that the electric current will circulate in a certain direction. Currently, hang-type insulators at home and abroad can be divided into ceramic insulators, glass insulators and composite insulators. Ceramic and glass insulators are fragile and susceptible to contamination, tending to cause accidents such as high voltage flashover and exploding bottle cracks. The mandrel of common rod-shaped composite insulators exhibit poor flexibility in resisting bending and are fragile as well. Today, insulators made of organic composite materials, i.e. composite insulators, are widely used at home and abroad.
End attachments of an insulator are used to connect and fix the insulator to electricity transmission lines and telegraph poles. These end attachments not only sustain various external forces inside the system and pressure produced by transmission wires themselves, but also sustain wind forces from uncertain directions and pressure resulted from accumulated snow during a long term use. Therefore, the connecting quality between end attachments and the mandrel is a significant symbol which directly affects the safety and reliability of product operation. A commonly used connecting technique is to connect a mandrel with end attachments by press-fit assembly process. However, such process tends to induce cracking, loosening and aging and leads to poor stability, thus becoming a potential safety hazard. Currently, it is still a big problem to improve the connecting quality in the field of composite insulators both at home and abroad.

SUMMARY OF THE INVENTION

The object of the invention is to, addressing the above existing problems and shortcomings, provide a hang-type composite insulator which has good flexibility, contamination and cracking resistance. In addition, such hang-type composite insulator can generate a connection which is safe and has high strength, good stability, durability and anti-aging capability.
The technical solution of the invention is achieved as follows.
A hang-type composite insulator, comprising a mandrel (1), an umbrella-skirt sheath (2) disposed outside the mandrel (1) and end assemblies (3) disposed at both ends of the mandrel (1), characterized in that, orientated glass fiber is used as reinforced body material for mandrel and is then formed into a rod stock by using soft dielectric rubber material or flexible plastic as an adhesive.
In order to enhance pressure and contamination resistant capabilities, the umbrella-skirt sheath is made of dielectric polymer material such as silicon rubber, ethylene propylene diene rubber, or soft plastic etc. The umbrella-skirt sheath can be integrally molded on the mandrel or sheath-covered to the mandrel.
The end assemblies comprise a sleeve with a tapered aperture, a flared conical body for inserting into any end of the mandrel, a locking nut and a connection member, wherein: the flared conical body is generally cone-shaped, the head of which is provided with chamfered edges preventing disengagement thereof; the sleeve is a tubular member, an inner aperture of the small diameter end of the sleeve corresponds to the diameter of the mandrel or interference-fits with the mandrel, an inner aperture of the large diameter end of the sleeve is configured into a horn shape, the inner wall of the horn shaped aperture is formed with inner teeth, an outer circumference of the large diameter end of the sleeve is provided with a protruding step; one end of the locking nut is provided with an internal thread, and a recessed step is provided inside the locking nut which engages with the protruding step; one end of the connection member is provided with an external thread which engages the internal thread, the other end of the connection member is configured into a ball-head shape, a ball-socket shape, or a flying ring shape to facilitate connection and fixation; an equalizer ring is further provided on end assemblies to make the connection between end assemblies and the mandrel more stable.
Orientated glass fiber is used as reinforced body material for the mandrel of the invention, and the rod stock is formed by using soft dielectric rubber material or flexible plastic as an adhesive. Therefore, the insulator will exhibit flexibility and reliable connection strength as well as favorable contamination resistance and portability. The insulator will not bend to crack or fatigue to fracture due to wind swinging during transportation and usage, thus effectively avoiding accidents of high voltage flashover or exploding bottle cracks as well as improving life span of products. In addition, the invention has the above structure of the end assemblies, such flared conical body connection technique makes the connection strength between the end assembly and the mandrel higher than that of the conventional press-fit technique. During usage of the insulator, the mandrel will not easily disengage from the end assembly. Cracks due to stress fatigue or processing defects and fatigued fracture caused by wind swinging will not happen. The size of the diameter of the flexible mandrel in accordance with the invention can be determined by tension load of the product. The length of the composite hang-type insulator, the number and shape of the umbrella-skirt sheath as well as the type of end assembly are determined by the level of contamination resistance and characteristics of the application. The invention can meet the using requirements of various insulation levels and strength levels. The invention is also superior to existing string-type insulator or rod type composite insulator in terms of life span, safety and reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

Hereinafter, the invention will be further described with reference to the accompanied drawings.
Figure 1 is a schematic structure view of an umbrella-skirt sheath being socket-coupled to the mandrel in accordance with the invention;
Figure 2 is a schematic structure view of an umbrella-skirt sheath being integrally molded to the mandrel in accordance with the invention;
Figure 3 is a partially sectional view of the insulator in accordance with the invention;
Figure 4 is a schematic exploded view of the invention;
Figure 5 is a partially sectional view of the invention provided with an equalizer ring; and
Figure 6 is a schematic exploded view of the invention provided with an equalizer ring.

DETAILED DESCRIPTION OF THE INVENTION

As shown in the Figures, a hang-type composite insulator comprises a mandrel 1, an umbrella-skirt sheath 2 disposed outside the mandrel 1 and assemblies 3 disposed at both ends of the mandrel 1. The mandrel 1 uses orientated glass fiber as the primary reinforcing material and is then formed into a rod stock by using soft dielectric rubber material or flexible plastic as an adhesive.
The umbrella-skirt sheath 2 is made of dielectric polymer material such as silicon rubber, ethylene propylene diene rubber, or soft plastic etc. The umbrella-skirt sheath 2 serves to protect the mandrel, increase the creepage distance and prevent contamination and can be formed into various shapes according to pressure resistant level and contamination resistant level. The umbrella-skirt sheath 2 can be sheath-covered on the mandrel 1, as shown in Fig.1, or can be integrally molded on the mandrel 1, as shown in Fig.2.
As shown in Figs. 3 and 4, a sleeve 4 with a tapered aperture, a flared conical body 5, a locking nut 6 and a connection member 7 constitute an end assembly 3, wherein the sleeve 4 is a tubular member, an inner aperture of the small diameter end of the sleeve 4e corresponds to the diameter of the mandrel 1 or interference-fits with the mandrel 1, an inner aperture of the large diameter end of the conical-opening sleeve is configured into a horn shape, the inner wall of the horn shaped aperture is formed with inner teeth, an outer circumference of the large diameter end is provided with a protruding step 41; the inner aperture of the locking nut 6 is provided with a recessed step 61, and one end of the inner aperture of the locking nut 6 is provided with an internal thread 62; the connection member 7 is provided with an external thread 71 which engages the internal thread 62.
When assembling, firstly, the sleeve 4 is passed through the locking nut 6 so that the protruding step 41 of the sleeve 4 abuts against the recessed step 61 of the locking nut 6. Then, the mandrel 1 covered with the umbrella-skirt sheath 2 is passed through the small diameter end of the sleeve 4 until the mandrel 1 exceeds a certain distance. After that, the flared conical body 5 is inserted into the mandrel 1 along the axial direction of the mandrel 1 so that the mandrel 1 is expanded. Next, the mandrel 1 is pulled in the reverse direction so that the expanded portion of the mandrel 1 presses against the inner wall of the horn shaped aperture. The inner teeth provided on the inner wall of the horn shaped aperture can effectively increase the friction coefficient. Finally, the connection member 7 is screwed into the locking nut 6 to provide a further pressure on it.
The connection member 7 can be of various shapes for the sake of its connection with electricity transmission lines and telegraph poles. As shown in Fig.1, the end portion of the connection member 7 is of a ball-head shape. As shown in Fig.2, the end portion is of a ball-socket shape. As shown in Fig.5, the end portion is of a flying ring shape.
In order that the connection between the end assembly 3 and the mandrel 1 is more stable, an equalizer ring 8 is further provided outside the end assembly 3, as shown in Figs.5 and 6.
While the invention has been described with reference to particular embodiments, such description is not intended to limit the invention. With reference to the above description, all other variations of the disclosed embodiment which are envisaged by those skilled in the art, will fall within the scope and spirit defined by the appended claims.

Claims

A hang-type composite insulator, comprising a mandrel (1), an umbrella-skirt sheath (2) disposed outside the mandrel (1) and end assemblies (3) disposed at both ends of the mandrel (1), characterized in that, orientated glass fiber is used as reinforced body material for mandrel and is then formed into a rod stock by using soft dielectric rubber material or flexible plastic as an adhesive; the end assemblies (3) comprise a sleeve (4) with a tapered aperture, a flared conical body (5) for inserting into any end of the mandrel (1), a locking nut (6) and a connection member (7), wherein:
the flared conical body (5) is generally cone-shaped, the head of which is provided with chamfered edges for preventing disengagement thereof;

the sleeve (4) is a tubular member, an inner aperture of the small diameter end of the sleeve (4) corresponds to the diameter of the mandrel (1) or interference-fits with the mandrel (1), an inner aperture of the large diameter end of the sleeve (4) is configured into a horn shape, the inner wall of the horn shaped aperture is formed with inner teeth, an outer circumference of the large diameter end of the sleeve (4) is provided with a protruding step (41);

one end of the inner aperture of the locking nut (6) is provided with an internal thread (62), and a recessed step (61) is provided inside the aperture which engages with the protruding step (41);

one end of the connection member (7) is provided with an external thread (71) which engages the internal thread (62).
A hang-type composite insulator according to Claim 1, characterized in that, an end equalizer ring (8) is provided on the outer circumference of the small diameter end of the sleeve (4).
A hang-type composite insulator according to Claim 1 or 2, characterized in that, the other end of the connection member (7) is configured into a ball-head shape, a ball-socket shape, or a flying ring shape.
A hang-type composite insulator according to Claim 1 or 2, characterized in that, the umbrella-skirt sheath (2) is made of dielectric polymer material.
A hang-type composite insulator according to Claim 4, characterized in that, the umbrella-skirt sheath (2) is integrally injection-molded to the mandrel (1).
A hang-type composite insulator according to Claim 4, characterized in that, the umbrella-skirt sheath (2) is sheath-covered to the mandrel (1).