An exhaust device for installing a cable joint

Abstract

The present invention discloses an exhaust device for cable joint installation, which includes an exhaust member provided with an exhaust passage therein. During installation, first insert the exhaust member into the inner cavity of the rubber prefabricated part, and then insert the cable, so that the exhaust member is clamped between the inner cavity wall of the rubber prefabricated part and the cable inserted into the inner cavity of the rubber prefabricated part. The gas enclosed in the rubber prefabricated part is discharged through the exhaust passage of the exhaust member, and then the exhaust member is withdrawn. The exhaust member is an exhaust strip made of insulating polymer material. This exhaust device can quickly and effectively discharge the gas in the enclosed space during cable joint installation, avoid the generation of air gaps at the insulation interface between the rubber prefabricated part and the cable, and eliminate the risks such as the reduction of the axial breakdown field strength caused by air gaps, the initiation of partial discharge, the influence on the electric field distribution, and the acceleration of insulation aging.

Description

Technical Field

[0001] The invention relates to a cable joint installation structure, in particular to a cable joint installation exhaust device. Background Art

[0002] As the proportion of power cables in power grids increases, cables and cable accessories are experiencing more and more frequent failures due to installation problems. The removal of interface gas during the installation of cable accessories is a key factor in ensuring product quality. For plug-in structure cable accessories, there is a closed space where gas cannot be discharged. It is necessary to have a suitable method to discharge the gas at the interface between rubber preforms and cable insulation. The existence of air gaps greatly reduces the starting voltage of local discharge along the surface, weakens the role of the stress cone in evacuating the electric field, and seriously affects the interface pressure between the cone of the stress cone and the cable insulation surface, which may cause insulation breakdown and insulation surface creepage.

[0003] In order to avoid the generation of air gaps, the current method is to leave the rubber preform of the cable joint stationary for a long time after installation, and exhaust the air by means of the clamping force between the rubber preform and the cable insulation. However, the exhaust time is long and the effect is not good. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned problems and provide a cable joint installation exhaust device, which can quickly and effectively exhaust the gas in the enclosed space during the installation of the cable joint, avoid the formation of air gaps at the interface between the rubber preform and the cable insulation, and eliminate the risks of reduced axial breakdown field strength, inducing local discharge, affecting electric field distribution, and accelerating insulation aging caused by the air gap.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A cable joint installation exhaust device comprises an exhaust member, wherein an exhaust passage is provided in the exhaust member;

[0007] During the installation operation, the exhaust piece is first inserted into the inner cavity of the rubber preform, and then the cable is inserted, so that the exhaust piece is clamped between the inner cavity wall of the rubber preform and the cable inserted into the inner cavity of the rubber preform, and the gas enclosed in the rubber preform is discharged through the exhaust channel of the exhaust piece, and the exhaust piece is pulled out.

[0008] A preferred embodiment of the present invention is that the exhaust component is an exhaust strip made of an insulating polymer material; specifically, the exhaust strip is made of a composite porous material of polytetrafluoroethylene-modified PEEK and porous glass microbeads, and has a smooth surface and all sharp edges are rounded to avoid the introduction of conductive impurities and scratches on cables or joint rubber preforms during use.

[0009] The melting point of PEEK is as high as 343°C, which can maintain stable performance in high temperature environments, ensuring that the performance of the tooling is stable within the working temperature.

[0010] Superior mechanical properties: PEEK has high strength, rigidity and toughness. The tensile strength of PEEK is usually between 90 - 150 MPa, capable of withstanding large mechanical stresses and loads, and has excellent wear resistance.

[0011] Chemical corrosion resistance: It has strong resistance to a variety of chemical substances and maintains its chemical stability especially when in contact with acids, alkalis and organic solvents.

[0012] Low coefficient of friction: Its surface has a low coefficient of friction and has good self - lubricating properties, so it is very useful in applications where wear and friction need to be reduced.

[0013] Superior electrical properties: PEEK has good electrical insulation properties and can remain stable even at high temperatures.

[0014] A preferred embodiment of the present invention, wherein the parts of the exhaust strip in contact with the rubber pre - forms of the cable and the joint are all in arc structures.

[0015] A preferred embodiment of the present invention, wherein one end of the exhaust member that is not inserted into the rubber pre - form is provided with a mounting portion.

[0016] Furthermore, a pull - tab for pulling out the exhaust strip is installed on the mounting portion, and the pull - tab is connected to the mounting portion through a pin shaft.

[0017] A preferred embodiment of the present invention, wherein it further includes a vacuum pump and an exhaust pipe. One end of the exhaust pipe is communicated with one end of the exhaust channel of the exhaust strip through a pipe joint, and the other end of the exhaust pipe is communicated with the vacuum pump. With the above structure, after the cable is inserted, the gas enclosed in the rubber pre - form can be completely exhausted through the vacuum pump.

[0018] Furthermore, the vacuum pump is a self - expanding vacuum device, with a high - strength low - permeability flexible material on the outside and energy - storage components such as springs pre - formed inside. Before leaving the factory, the energy - storage components are compressed and the end valves are closed. When used on - site, opening the valves can form a vacuum, and different - volume devices can be used in combination according to actual needs.

[0019] The working principle of the above - mentioned cable joint installing the exhaust device is as follows:

[0020] During installation, the exhaust strip is placed into the inner hole of the joint's rubber pre - form coated with lubricant, and then the cable coated with lubricant is inserted into the inner hole of the rubber pre - form. Since the interfacial pressure between the rubber pre - form and the cable is ensured by interference fit, when the cable is inserted a certain length, a closed chamber is formed inside the rubber pre - form, resulting in the inability of gas to be discharged. By setting the exhaust strip, the closed chamber can be communicated with the external space to discharge the air in the closed chamber.

[0021] Furthermore, to prevent the lubricant applied during the process of inserting the cable into the rubber preform from entering the exhaust channels of the exhaust strip, causing blockage of the exhaust channels and preventing the full discharge of the gas in the closed chamber, after the cable is fully inserted into the rubber preform, an exhaust pipe is installed on the exhaust strip. The exhaust pipe is connected to a vacuum pump, and the gas in the closed chamber is completely discharged by means of vacuum pumping. Finally, the exhaust strip is pulled out of the rubber preform through a snap fastener.

[0022] A preferred embodiment of the present invention, wherein the exhaust member is a hollow long strip airbag, and one end of the hollow long strip airbag that is not inserted into the rubber preform is connected to an air inflation pump through an air inflation pipe;

[0023] During the installation operation, first lay the uninflated hollow long strip airbag in the inner cavity of the rubber preform. After inserting the cable, inflate the hollow long strip airbag through the air inflation pump. The hollow long strip airbag enters the inflated state and presses against the inner cavity wall of the rubber preform and the outer wall of the cable. At this time, the hollow structure inside the hollow long strip airbag constitutes the exhaust channel.

[0024] Furthermore, a pulling member is fixedly connected to one end of the hollow long strip airbag inserted into the rubber preform, and the pulling member extends to the outside through the hollow structure of the hollow long strip airbag; when the pulling member is pulled outwards to pull the hollow long strip airbag, the hollow long strip airbag is withdrawn from the rubber preform in an inverting manner. Through the above structure, after the gas is discharged, the pulling member can be pulled outwards to take out the hollow long strip airbag from the rubber preform in an inverting manner. Further, when the inner end of the hollow long strip airbag is inverted by the pulling member, the outer wall of the hollow long strip airbag is gradually peeled off from the inner cavity wall of the rubber preform and the outer wall of the cable. At this time, the hollow long strip airbag and the inner cavity wall of the rubber preform and the outer wall of the cable will gradually not have sliding friction, thereby greatly reducing the risk of adhering conductive particles and ensuring electrical safety. In addition, when the hollow long strip airbag is inverted. The inverted part will enter the hollow structure of the hollow long strip airbag, thereby driving the air towards the outlet direction and further discharging the internal air to prevent the air from affecting electrical safety.

[0025] Furthermore, a deflation valve is provided at one end of the hollow long strip airbag that is not inserted into the rubber preform; when the hollow long strip airbag is withdrawn from the rubber preform in an inverting manner, the deflation valve is opened to gradually reduce the air pressure inside the hollow long strip airbag, and the hollow long strip airbag contracts and moves outwards while.

[0026] Furthermore, the pulling member is a pull rope, and one end of the pull rope is fixedly connected to one end of the hollow long strip airbag inserted into the rubber preform.

[0027] The present invention has the following beneficial effects compared with the prior art:

[0028] The cable joint installation exhaust device of the present invention can quickly and effectively discharge the gas in the closed space during the installation of the cable joint, avoid the generation of air gaps at the interface between the rubber prefabricated part and the cable insulation, and eliminate the risks such as the reduction of the axial breakdown field strength caused by the air gap, the initiation of partial discharge, the influence on the electric field distribution, and the acceleration of insulation aging. Brief Description of the Drawings

[0029] Figure 1 It is a sectional view schematic diagram of one implementation manner of the cable joint installation exhaust device of the present invention.

[0030] Figures 2-6 It is a sectional view schematic diagram of multiple different working states of one implementation manner of the cable joint installation exhaust device of the present invention.

[0031] Figures 7-9 It is a partial sectional view schematic diagram of multiple different working states of another implementation manner of the cable joint installation exhaust device of the present invention. Detailed Implementation Manner

[0032] In order to enable those skilled in the art to well understand the technical solution of the present invention, the present invention will be further described below in combination with embodiments and drawings, but the implementation manners of the present invention are not limited thereto.

[0033] Embodiment 1

[0034] Refer to Figure 1 , the cable joint installation exhaust device of this embodiment includes an exhaust member 1, a vacuum pump 2, and an exhaust pipe 3. An exhaust passage 1-1 is provided inside the exhaust member 1; one end of the exhaust pipe 3 is connected to one end of the exhaust passage 1-1 of the exhaust member 1 through a pipe joint, and the other end of this exhaust pipe 3 is connected to the vacuum pump 2.

[0035] During the installation operation, first insert the exhaust member 1 into the inner cavity of the rubber prefabricated part 4, and then insert the cable 5, so that the exhaust member 1 is clamped between the inner cavity wall of the rubber prefabricated part 4 and the cable 5 inserted into the inner cavity of the rubber prefabricated part 4. The gas enclosed in the rubber prefabricated part 4 is discharged through the exhaust passage 1-1 of the exhaust member 1, and then the exhaust member 1 is taken out.

[0036] Furthermore, the exhaust member 1 is an exhaust strip made of an insulating polymer material; specifically, the exhaust strip is made of a composite porous material of PTFE-modified PEEK and porous glass microspheres. Its surface is smooth, and all sharp edges are rounded to avoid introducing conductive impurities, scratching the cable 5 or the joint rubber prefabricated part 4 during use.

[0037] The melting point of PEEK is as high as 343 °C, which can maintain stable performance in a high-temperature environment and ensure that the tooling will not be affected by temperature within the working range.

[0038] Superior mechanical properties: PEEK has high strength, rigidity and toughness. The tensile strength of PEEK is usually between 90 - 150 MPa, capable of withstanding large mechanical stresses and loads, and it has excellent wear resistance.

[0039] Chemical corrosion resistance: It has strong resistance to a variety of chemical substances, especially maintaining its chemical stability when in contact with acids, alkalis and organic solvents.

[0040] Low coefficient of friction: Its surface coefficient of friction is low, with good self - lubricating properties, so it is very useful in applications where wear and friction need to be reduced.

[0041] Superior electrical properties: PEEK has good electrical insulation properties and can remain stable even at high temperatures.

[0042] Specifically, the parts of the exhaust strip in contact with the cable 5 and the rubber pre - form 4 of the joint both adopt arc structures.

[0043] See Figure 1 , one end of the exhaust part 1 that is not inserted into the rubber pre - form 4 is provided with an installation part 1 - 2.

[0044] Furthermore, a pull - tab 6 for pulling out the exhaust strip is installed on the installation part 1 - 2, and the pull - tab 6 is connected to the installation part 1 - 2 through a pin shaft.

[0045] Specifically, the vacuum pump 2 is a self - expanding vacuum device, with a high - strength and low - air - permeability flexible material on the outside, and energy - storage components such as springs pre - fabricated inside. Before leaving the factory, the energy - storage components are compressed and the end valves are closed. When used on - site, opening the valves can form a vacuum, and different - volume devices can be used in combination according to actual needs.

[0046] See Figures 1-6 , the working principle of installing the exhaust device for the cable joint in this embodiment is as follows:

[0047] During installation, the exhaust strip is placed into the inner hole of the rubber pre - form 4 of the joint coated with lubricant, as Figure 2 , and then the cable 5 coated with lubricant is inserted into the inner hole of the rubber pre - form 4, as Figure 3 . Since the interfacial pressure between the rubber pre - form 4 and the cable 5 is ensured by interference fit, when the cable 5 is inserted a certain length, a closed chamber is formed inside the rubber pre - form 4, resulting in the inability of gas to be discharged. By setting the exhaust strip, the closed chamber can be connected to the external space, enabling the air in the closed chamber to be discharged, as Figure 4 .

[0048] Further, to prevent the lubricant applied during the insertion of the cable 5 into the rubber preform 4 from entering the exhaust passage 1-1 of the exhaust strip, causing blockage of the exhaust passage 1-1 and preventing the complete discharge of the gas in the closed chamber, after the cable 5 is completely inserted into the rubber preform 4, an exhaust pipe 3 is installed on the exhaust strip. The exhaust pipe 3 is connected to a vacuum pump 2, and the gas in the closed chamber is completely discharged by means of vacuum pumping, as Figure 5 shown. Finally, the exhaust strip is pulled out of the rubber preform 4 through a snap fastener 6, as Figure 6 .

[0049] Embodiment 2

[0050] Refer to Figures 7-9 . Different from Embodiment 1, the exhaust member 1 in this embodiment is a hollow long strip airbag. One end of the hollow long strip airbag that is not inserted into the rubber preform 4 is connected to an air inflation pump through an air inflation pipe; during the installation operation, the uninflated hollow long strip airbag is first laid in the inner cavity of the rubber preform 4, and the cable 5 is inserted, as Figure 7 shown. At this time, the hollow long strip airbag is in a flat state, and there is almost no ventilation gap between the inner cavity wall of the rubber preform 4 and the cable 5 when they are squeezed. The hollow long strip airbag is inflated through the air inflation pump, and the hollow long strip airbag enters the inflated state and squeezes the inner cavity wall of the rubber preform 4 and the outer wall of the cable 5. At this time, the hollow structure inside the hollow long strip airbag constitutes the exhaust passage 1-1, as Figure 8 .

[0051] Further, one end of the hollow long strip airbag inserted into the rubber preform 4 is fixedly connected with a pulling-out member 6, and the pulling-out member 6 extends to the outside through the hollow structure of the hollow long strip airbag; when the pulling-out member 6 is pulled outwards to pull the hollow long strip airbag, the hollow long strip airbag is withdrawn from the rubber preform 4 in an inverting manner, as Figure 9 shown. Through the above structure, after the gas is discharged, the pulling-out member 6 can be pulled outwards to take out the hollow long strip airbag from the rubber preform 4 in an inverting manner. Further, when the pulling-out member 6 pulls the inner end of the hollow long strip airbag to invert, the outer wall of the hollow long strip airbag is gradually peeled off from the inner cavity wall of the rubber preform 4 and the outer wall of the cable 5. At this time, the hollow long strip airbag and the inner cavity wall of the rubber preform 4 and the outer wall of the cable 5 will gradually not have sliding friction, thereby greatly reducing the risk of adhering conductive particles and ensuring electrical safety. In addition, when the hollow long strip airbag is inverting. The inverting part will enter the hollow structure of the hollow long strip airbag, thereby driving the air towards the outlet direction and further discharging the internal air to prevent the air from affecting electrical safety.

[0052] Further, a deflation valve is provided at one end of the hollow long strip airbag that is not inserted into the rubber preform 4; when the hollow long strip airbag is withdrawn from the rubber preform 4 in an inverting manner, the deflation valve is opened to gradually reduce the air pressure inside the hollow long strip airbag, and the hollow long strip airbag shrinks and moves outwards at the same time.

[0053] Furthermore, the extraction member 6 is a drawstring, and one end of the drawstring is fixedly connected to one end of the hollow long-strip airbag inserted into the rubber preform 4.

[0054] The above is a preferred embodiment of the present invention. However, the embodiments of the present invention are not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. An exhaust device for installing a cable joint, characterized in that It includes an exhaust component, and an exhaust passage is provided inside the exhaust component; During installation, first insert the exhaust component into the inner cavity of the rubber preform, and then insert the cable, so that the exhaust component is clamped between the inner cavity wall of the rubber preform and the cable inserted into the inner cavity of the rubber preform. The gas enclosed in the rubber preform is discharged through the exhaust passage of the exhaust component, and then the exhaust component is withdrawn; The exhaust component is a hollow long balloon, and one end of the hollow long balloon that is not inserted into the rubber preform is connected to an air pump through an air filling pipe; During installation, first lay the non-inflated hollow long balloon in the inner cavity of the rubber preform. After inserting the cable, inflate the hollow long balloon through the air pump. The hollow long balloon enters the inflated state and presses against the inner cavity wall of the rubber preform and the outer wall of the cable. At this time, the hollow structure inside the hollow long balloon constitutes the exhaust passage; One end of the hollow long balloon inserted into the rubber preform is fixedly connected with a pulling-out component, and the pulling-out component extends to the outside through the hollow structure of the hollow long balloon; when the pulling-out component pulls the hollow long balloon outwards, the hollow long balloon is turned inside out and withdrawn from the rubber preform.

2. The exhaust device for cable joint installation according to claim 1, wherein One end of the hollow long balloon that is not inserted into the rubber preform is provided with a deflation valve; when the hollow long balloon is turned inside out and withdrawn from the rubber preform, open the deflation valve to gradually reduce the air pressure inside the hollow long balloon, and the hollow long balloon shrinks and moves outwards at the same time.

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