A device for pressure balance inside a cable terminal and a cable terminal using the same

Abstract

The present invention discloses a device for pressure balance inside a cable terminal and a cable terminal using the same, which relates to the technical field of cable terminals. The device includes a membrane body and a connecting device. The membrane body encloses a first chamber with variable volume, and the membrane body is used to be installed in the insulation chamber of the cable terminal. The connecting device has a first end and a second end that are connected. The connecting device is connected to the membrane body, and the second end of the connecting device is communicated with the first chamber, and the first end of the connecting device is used to communicate with the external environment. The device for pressure balance inside the cable terminal of the present invention can adjust the pressure inside the cable terminal and always maintain the internal pressure balance of the cable terminal.

Description

Technical Field

[0001] The present invention relates to the technical field of cable terminals, and particularly to a device for pressure balance inside a cable terminal and a cable terminal using the same. Background Art

[0002] A cable terminal generally includes a cable and a sleeve sleeved outside the cable. In order to facilitate the connection of a conductive terminal at the end of the cable, the insulating layer of the cable inside the sleeve will be peeled off. At the same time, in order to restore the insulating ability of the cable, an insulating material will be filled between the cable and the sleeve.

[0003] Common insulating materials are liquid insulating agents, such as silicone oil, polyisobutylene, silicone gel, etc. The volume of these insulating materials is easily changed by temperature variations. Therefore, the insulating material does not completely fill the space between the cable and the sleeve, but a cavity with a certain distance is reserved. When the cable terminal is operating, the current flowing through the cable generates heat, and the heat radiates into the interior of the cable terminal, causing the temperature of the insulating material to rise, and the insulating material expands thermally and its volume increases. The interior of the cable terminal is sealed. While the volume of the insulating material increases, it will squeeze and compress the gas in the cavity, causing the air pressure inside the cable terminal to increase. The structure of the cable terminal will bear a large pressure, especially the sealing structure at the bottom of the cable terminal. Long-term exposure to large pressure and heat is prone to aging and failure, resulting in leakage of the insulating material and damage to the cable terminal. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a device for pressure balance inside a cable terminal, which can adjust the pressure inside the cable terminal and always maintain the internal pressure balance of the cable terminal.

[0005] The present invention also provides a cable terminal.

[0006] The device for pressure balance inside a cable terminal according to the first aspect embodiment of the present invention includes a membrane body, the membrane body encloses a first chamber with variable volume, and the membrane body is used to be installed in the insulating cavity of the cable terminal;

[0007] A communicating device, the communicating device has a first end and a second end that are communicated, the communicating device is connected to the membrane body, and the second end of the communicating device is communicated with the first chamber, and the first end of the communicating device is used to communicate with the external environment.

[0008] The device for pressure balance inside a cable terminal according to an embodiment of the present invention has at least the following beneficial effects: The membrane body encloses a first chamber with variable volume. The membrane body is used to be installed in the insulation chamber of the cable terminal, such that the first chamber occupies a part of the volume of the insulation chamber. When the insulator inside the insulation chamber expands due to heat, it can squeeze the membrane body to reduce the volume of the first chamber, and the gas inside the first chamber can be discharged to the external environment through the communication device, reducing the pressure increased by the thermal expansion of the insulator; when the insulator cools and contracts, the gas in the external environment can enter the first chamber again through the communication device, increasing the volume of the first chamber and reoccupying the vacancy generated in the insulation chamber due to the contraction of the insulator; the gas in the external environment always flows inside the first chamber, which will not cause pollution to the insulation chamber and the insulator, and will not change the physical properties inside the cable terminal, and the cable terminal can operate stably and safely.

[0009] According to some embodiments of the present invention, the communication device includes a filtering component and a conducting component. One end of the conducting component is communicated with the first chamber, the filtering component is connected to the other end of the conducting component, and the filtering component is used to communicate with the external environment.

[0010] According to some embodiments of the present invention, the filtering component includes a first housing and a filtering material. The first housing has a filtering cavity. The first housing is provided with a first through hole, and the first through hole communicates the filtering cavity with the external environment. The first housing is provided with a second through hole, and the second through hole communicates the filtering cavity with the conducting component. The filtering material is filled in the filtering cavity and is located between the first through hole and the second through hole.

[0011] According to some embodiments of the present invention, the filtering cavity is filled with granular filtering material, and the first housing is provided with a plurality of the second through holes, and the inner diameter of the second through hole is smaller than the size of the filtering material.

[0012] According to some embodiments of the present invention, the first through hole is arranged at the top of the first housing, and the second through hole is arranged at the bottom of the first housing.

[0013] According to some embodiments of the present invention, the conducting component includes a conduit and a second housing. The second housing is arranged in the first chamber. The second housing has a second chamber. The second housing is provided with a third through hole. The first chamber is communicated with the second chamber through the third through hole. One end of the conduit is communicated with the filtering component, and the other end of the conduit extends into the second chamber.

[0014] According to some embodiments of the present invention, a barrier liquid is added to the second chamber, the liquid level of the barrier liquid is higher than the port of the conduit, and the liquid level of the barrier liquid is lower than the third through hole.

[0015] According to some embodiments of the present invention, a third housing is provided between the catheter and the filter assembly. The third housing has a third chamber, the third chamber communicates with the filter assembly, and the third chamber communicates with the second chamber through the catheter.

[0016] According to some embodiments of the present invention, the conduction assembly further includes a first connection plate and a second connection plate. The catheter is disposed on one side surface of the first connection plate, the other side surface of the first connection plate is connected to the filter assembly, the second housing is disposed on one side surface of the second connection plate, the other side surface of the second connection plate is connected to the first connection plate, and the first connection plate is located on the opposite surface of the second connection plate. The catheter extends into the second chamber.

[0017] According to the cable terminal of the second aspect embodiment of the present invention, the cable terminal is equipped with the above-mentioned device for pressure balance inside the cable terminal.

[0018] The cable terminal according to the embodiment of the present invention has at least the following beneficial effects: The membrane encloses a first chamber with a variable volume. The membrane is installed in the insulation cavity of the cable terminal, and the first chamber occupies a part of the volume of the insulation cavity. When the insulation inside the insulation cavity expands due to heat, it can squeeze the membrane to reduce the volume of the first chamber, and the gas in the first chamber can be discharged to the external environment through the communication device, reducing the pressure increased by the thermal expansion of the insulation; when the insulation cools and contracts, the gas in the external environment can enter the first chamber again through the communication device, increasing the volume of the first chamber and reoccupying the vacancy generated in the insulation cavity due to the contraction of the insulation; the gas in the external environment always flows in the first chamber, which will not cause pollution to the insulation cavity and the insulation, and will not change the physical properties inside the cable terminal, and the cable terminal can operate stably and safely.

[0019] The additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following further describes the present invention in conjunction with the drawings and embodiments, where:

[0021] Figure 1 is a schematic structural diagram of the device for pressure balance inside the cable terminal according to the embodiment of the present invention;

[0022] Figure 2 is a schematic structural diagram of the device for pressure balance inside the cable terminal according to the embodiment of the present invention installed in the cable terminal;

[0023] Figure 3 is a schematic structural diagram of the communication device according to the embodiment of the present invention;

[0024] Figure 4 Structural schematic diagram of the filtering component and the conducting component according to an embodiment of the present invention;

[0025] Figure 5 Structural schematic diagram of the conducting component according to an embodiment of the present invention.

[0026] Reference numerals in the drawings:

[0027] Film body 100, connection device 200, filtering component 210, first housing 211, filter material 212, first through hole 213, second through hole 214, conducting component 220, conduit 221, second housing 222, third through hole 223, barrier liquid 224, third housing 225, first connecting plate 226, second connecting plate 227, cable terminal 300, protective cover 310, cable 320, sleeve 330, cover 400. Detailed implementation manners

[0028] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0029] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as up and down, etc., is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0030] In the description of the present invention, "a plurality of" refers to more than two. If there is a description of first and second, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0031] In the description of the present invention, unless otherwise clearly defined, terms such as "set", "installed", "connected", etc. should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0032] A cable terminal generally includes a cable and a sleeve sleeved outside the cable. In order to facilitate the connection of a conductive terminal at the end of the cable, the insulating layer of the cable inside the sleeve will be peeled off. At the same time, in order to restore the insulation ability of the cable terminal, an insulating material will be filled between the cable and the sleeve.

[0033] Common insulating materials are liquid insulating agents, such as silicone oil, polyisobutene, silicone gel, etc. However, the volume of these insulating materials is easily changed by temperature variations. Therefore, the space between the cable and the bushing is not completely filled with the above-mentioned insulating materials, but a cavity with a certain distance is reserved. The cavity is generally occupied by air, and air can be compressed and can adapt to the volume change of the insulating material within a certain range. And in order to prevent the leakage of the insulating material and ensure that the insulating material is not contaminated and its insulating properties are not changed, the interior of the cable terminal is a closed structure, that is, after the insulating material is filled between the cable and the bushing, the cable terminal is sealed.

[0034] When the cable terminal is operating, the current flowing through the cable has a thermal effect, and the heat generated is radiated to the interior of the cable terminal, causing the temperature of the insulating material to rise. The thermal expansion of the insulating material leads to an increase in volume. However, the interior of the cable terminal is closed. When the volume of the insulating material increases, the volume of the cavity decreases, and the gas in the cavity is squeezed and compressed, resulting in an increase in the air pressure inside the cable terminal. The increase in the air pressure inside the cable terminal will exert a large pressure on the structure of the cable terminal, especially the sealing structure at the bottom of the cable terminal. It is prone to aging and failure under long-term large pressure and heating conditions, resulting in the leakage of the insulating material and the damage of the cable terminal, and even the cable terminal explodes due to high internal pressure.

[0035] Refer to Figure 1 As shown, a device for pressure balance inside a cable terminal according to an embodiment of the present invention includes a membrane body 100 and a communication device 200.

[0036] The membrane body 100 encloses a first chamber with a variable volume, and the membrane body 100 is used to be installed in the insulating cavity of the cable terminal.

[0037] Taking a cable terminal 300 as an example, an insulating cavity is provided inside the cable terminal 300, and the insulating cavity is filled with an insulating material. Specifically, the cable terminal 300 includes a cable 320 and a bushing 330 sleeved outside the cable 320. Since the original insulating layer of the cable 320 inside the bushing 330 has been peeled off, an insulating material must be refilled between the cable 320 and the bushing 330, and the gap between the cable 320 and the bushing 330 is the insulating cavity.

[0038] The insulating material filled in the insulating cavity is used to maintain the insulation of the cable 320. The insulating material can be selected from silicone oil, polyisobutene or silicone gel and is added by perfusion. Generally speaking, the cable terminal 300 is vertically arranged, that is, the insulating cavity is distributed vertically. After the insulating material is filled into the insulating cavity, it occupies the bottom of the insulating cavity. The insulating material filled in the insulating cavity will keep its liquid level height at 70% - 80% of the height of the insulating cavity, and the remaining part of the insulating cavity can be used for the installation of the membrane body 100.

[0039] The membrane body 100 can be made of a flexible material, which can change the shape of the membrane body 100 to achieve a variable volume of the first chamber. The first chamber surrounded by the membrane body 100 occupies the remaining part of the insulating chamber, that is, the insulating chamber is jointly occupied by the insulator and the first chamber. No other solids or liquids are filled in the first chamber, so the first chamber is generally filled with air.

[0040] It should be emphasized that the membrane body 100 is installed in the insulating chamber, and the first chamber surrounded by the membrane body 100 needs to be in a non-connected state with the insulating chamber.

[0041] Refer to Figure 2 and Figure 3 As shown in the figure, the connecting device 200 is used to be installed on the cable terminal 300. The connecting device 200 has a connected first end and a second end. The connecting device 200 is connected to the membrane body 100, and the second end of the connecting device 200 is communicated with the first chamber. The first end of the connecting device 200 is used to communicate with the external environment.

[0042] The first chamber is kept in communication with the external environment through the connecting device 200. When the volume of the first chamber changes, for example, when the volume of the first chamber decreases, the air in the first chamber is squeezed out through the connecting device 200 and escapes to the external environment. Therefore, the pressure in the first chamber is in a balanced state. If the volume of the first chamber increases, the air in the external environment can re-enter the first chamber through the connecting device 200 to prevent the pressure in the first chamber from decreasing. Therefore, the pressure in the first chamber is maintained near the normal atmospheric pressure.

[0043] The volume change of the first chamber is caused by the volume change of the insulator. When the cable terminal 300 is working, the heat generated by the current radiates into the insulating chamber, and the insulator expands due to heat and its volume increases. Since the volume of the insulating chamber is fixed, the insulator will squeeze the membrane body 100, and the deformation of the membrane body 100 causes the volume of the first chamber to decrease. Since the working current of the cable terminal 300 is not constant, the heat generated in different time periods changes. Coupled with the temperature change of the external environment, the temperature of the insulator also changes. So when the temperature of the insulator drops, the volume of the insulator will shrink again, forming a cavity with negative pressure in the insulating chamber, and these cavities will be filled by the membrane body 100, that is, the volume of the first chamber increases.

[0044] It should be understood that the volume change of the insulator in the insulating chamber is adjusted by changing the volume of the first chamber, so that the pressure in the insulating chamber is maintained at a constant value, generally the pressure is maintained near the atmospheric pressure. The insulating chamber and the first chamber are not connected, so pollutants such as moisture and particulate matter in the external environment will not enter the insulating chamber to contaminate the insulator, and the insulator will not leak to the external environment either. The insulation performance of the cable terminal 300 is guaranteed, and the cable terminal 300 can operate stably and safely.

[0045] Referring to Figure 3 as shown, it can be understood that the connection device 200 includes a filtering component 210 and a conducting component 220. One end of the first chamber is connected to the conducting component 220, the filtering component 210 is connected to the other end of the conducting component 220, and the filtering component 210 is used to connect to the external environment.

[0046] The gas in the first chamber is connected to the external environment through the conducting component 220 to maintain the pressure in the first chamber constant. At the same time, before the gas or air enters the first chamber, it has to flow through the filtering component 210 to block solid particles such as moisture and impurities in the air in the filtering component 210. If solid particles such as moisture and impurities in the air enter the first chamber through the conducting component 220, liquid water will be formed in the first chamber, or large chunks of solid impurities will accumulate, or a mixture of water and solid impurities will be formed. These substances will all cause a decrease in the volume of the first chamber, resulting in a decline in the pressure regulation ability of the first chamber. In addition, the solid impurities may damage the membrane body 100 during movement, or even cause the membrane body 100 to rupture, thereby connecting the insulating chamber and the first chamber, that is, the external environment is connected to the insulating chamber, and pollutants can enter the insulating chamber, and the insulating structure of the cable terminal 300 is thus damaged.

[0047] Referring to Figure 4 as shown, it can be understood that the filtering component 210 includes a first housing 211 and a filter medium 212. The first housing 211 has a filter cavity. The first housing 211 is provided with a first through hole 213, and the first through hole 213 connects the filter cavity to the external environment. The first housing 211 is provided with a second through hole 214, and the second through hole 214 connects the filter cavity to the conducting component 220. The filter medium 212 is filled in the filter cavity and is located between the first through hole 213 and the second through hole 214.

[0048] The filter medium 212 has a variety of optional types, such as granular filter materials or solid filter cotton. Generally, the first through hole 213 and the second through hole 214 are arranged opposite to each other, and the filter medium 212 can be filled between the first through hole 213 and the second through hole 214, so that air must pass through the filter medium 212 from the first through hole 213 to the second through hole 214. Of course, a guiding channel can also be provided in the first housing 211, and the channel passing through the filter medium 212 can also make air necessarily pass through the filter medium 212.

[0049] It can be understood that the filter cavity is filled with granular filter material, the first housing 211 is provided with a plurality of second through holes 214, and the inner diameter of the second through holes 214 is smaller than the size of the filter material. Preferably, the first through hole 213 is provided at the top of the first housing 211, and the second through hole 214 is provided at the bottom of the first housing 211.

[0050] The first through hole 213 is arranged at the top position of the first shell 211, and the second through hole 214 is arranged at the bottom position of the first shell 211. Because the filter material 212 is accumulated at the bottom of the filter chamber due to gravity, the first through hole 213 is arranged at the top, and the second through hole 214 is arranged at the bottom, which can satisfy that the filter material 212 is between the first through hole 213 and the second through hole 214. The external air entering the filter chamber through the first through hole 213 must pass through the filter material before entering the second through hole 214. In the above structure, the conduction component 220 is arranged at the bottom of the first shell 211, which is convenient for the conduction component 220 to communicate with the second through hole 214.

[0051] It should be understood that the filter material is preferably a granular filter material, which can form more pores in the filter cavity, less obstruction to the flow of air, and can increase the contact area between the air and the filter material, greatly improving the filtering effect and efficiency of the filter material. Preferably, the filter material can use granular activated carbon or silica particles or ceramic particles.

[0052] Reference Figure 4 and Figure 5 As shown, it can be understood that the conduction component 220 includes a conduit 221 and a second shell 222, the second shell 222 is arranged in the first chamber, the second shell 222 has a second chamber, the second shell 222 is provided with a third through hole 223, the first chamber and the second chamber are connected through the third through hole 223, one end of the conduit 221 is connected to the filter component 210, and the other end of the conduit 221 extends into the second chamber.

[0053] The third through hole 223 is also preferably provided in the upper half of the second shell 222, and the conduit 221 extends into the second chamber, and the end of the conduit 221 is preferably extended to the bottom near the second chamber. In the above structure, the flow path of the air from the external environment is: passing through the conduit 221 to reach the second chamber, then floating to the upper half of the second chamber, and finally entering the first chamber through the third through hole 223. Even if tiny solid impurities mixed in the air enter the conduit 221, they will be intercepted by the second chamber of the second shell 222. The second shell 222 is arranged to cooperate with the arrangement of the conduit 221, the main purpose of which is to form a buffer area for storing solid impurities, and to avoid solid impurities from entering the first chamber to damage the membrane body 100 as much as possible. The second shell 222 is provided as a safety redundancy.

[0054] Reference Figure 4 and Figure 5 As shown, it can be understood that the second chamber is added with barrier liquid 224, the liquid level of the barrier liquid 224 is higher than the port of the conduit 221, and the liquid level of the barrier liquid 224 is lower than the third through hole 223. Generally, the conduit 221 is arranged vertically.

[0055] When the volume of the first chamber decreases, the air in the first chamber is squeezed into the second chamber, and the air further pushes the barrier liquid 224 to rise along the conduit 221. The air above the conduit 221 can still pass through the filter assembly 210 to reach the external environment. Therefore, the pressure in the first chamber can still remain balanced. When the volume of the first chamber increases, the air in the external environment can re-enter the upper part of the conduit 221 through the filter assembly 210. At this time, the barrier liquid 224 in the conduit 221 will drop back into the second chamber, and the air in the second chamber can return to the first chamber. Therefore, the pressure in the first chamber can still remain balanced. The barrier liquid 224 can enter the conduit 221 and move, which can maintain the pressure balance between the upper and lower ends of the conduit 221. The liquid level of the barrier liquid 224 is higher than the port of the conduit 221 and lower than the third through-hole 223. While playing a role in sealing and isolation, the barrier liquid 224 can also enable the first chamber to retain its original function of adjusting pressure balance.

[0056] It can be understood that a third housing 225 is provided between the conduit 221 and the filter assembly 210. The third housing 225 has a third chamber, the third chamber is communicated with the filter assembly 210, and the third chamber is communicated with the second chamber through the conduit 221.

[0057] Furthermore, if the volume change of the first chamber is large, then the volume of the first chamber decreases significantly, and the amount of the barrier liquid 224 entering the conduit 221 will increase, and the conduit 221 may not be able to accommodate the barrier liquid 224. By providing the third housing 225 with a third chamber between the conduit 221 and the filter assembly 210, the barrier liquid 224 can enter the third chamber for temporary storage.

[0058] For example, if the heat generation of the cable is large and the volume of the insulating object expands greatly, resulting in a greater decrease in the volume of the first chamber, the air in the first chamber is squeezed into the second chamber, further squeezing the barrier liquid 224 into the conduit 221, and the barrier liquid 224 in the conduit 221 enters the third chamber, making the conduit 221 connected by air again, and the air pressure in the first chamber is balanced. When the volume of the first chamber tends to be stable, the air in the first chamber no longer enters the second chamber, and the barrier liquid 224 can flow back along the conduit 221 to the second chamber under the influence of gravity, re-forming a liquid seal. After the working condition of the cable changes and the heat generation decreases, the insulating object cools and its volume shrinks, the volume of the first chamber increases, and the air in the external environment passes through the filter assembly 210 and the third chamber to reach the conduit 221, and enters the second chamber along the conduit 221, and finally makes up in the first chamber in the form of bubbles passing through the barrier liquid 224.

[0059] It should be understood that the position where the conduit 221 is communicated with the third chamber is preferably set at the lowest position of the third chamber. If conditions permit, a guiding inclined surface can be provided at the bottom of the third chamber, and the conduit 221 is set and communicated with it at the lowest position of the guiding inclined surface.

[0060] Referring to Figure 5 as shown, it can be understood that the conduction component 220 further includes a first connection plate 226 and a second connection plate 227. The conduit 221 is disposed on one side surface of the first connection plate 226. The other side surface of the first connection plate 226 is connected to the filtering component 210. The second housing 222 is disposed on one side surface of the second connection plate 227. The other side surface of the second connection plate 227 is connected to the first connection plate 226, and the first connection plate 226 is located on the opposite surface of the second connection plate 227. The conduit 221 extends into the second chamber.

[0061] The conduction component 220 can be divided into two parts according to the first connection plate 226 and the second connection plate 227. The first connection plate 226 and the conduit 221 directly connected thereto form the first part; the second connection plate 227 and the second housing 222 directly connected thereto form the second part. The above structure facilitates the installation of the conduction component 220 on the structure of the cable terminal 300.

[0062] Referring to Figure 3 and Figure 5 as shown, taking the structure of a cable terminal 300 as an example, the cable terminal 300 includes a cable 320 and a sleeve 330 sleeved outside the cable 320. The gap between the cable 320 and the sleeve 330 is the insulation chamber. The end of the cable terminal 300 is further provided with a cover 400. The cover 400 covers the insulation chamber. The second connection plate 227 is attached to the cover 400 and is located inside the insulation chamber. The first connection plate 226 is also attached to the cover 400 and is located on the opposite surface of the second connection plate 227. The conduit 221 can pass through the cover 400 and extend into the second chamber. It should be understood that the first connection plate 226 and the second connection plate 227 are indirectly connected through the cover 400, and it should also be understood that the other side surface of the second connection plate 227 is connected to the first connection plate 226. In some other embodiments, the second connection plate 227 can indeed be directly connected to the first connection plate 226, and only need to embed the conduction component 220 through the cover 400.

[0063] In an embodiment where the first connection plate 226 and the second connection plate 227 are indirectly connected through the cover 400, the second connection plate 227 can be fixed to one side surface of the cover 400 by screws, and the first connection plate 226 can also be fixed to the other side surface of the cover 400 by screws. At the same time, the first connection plate 226 and the second connection plate 227 are in opposite positions. At this time, the conduit 221 can pass through the cover 400 and extend into the second housing 222. Finally, when the cover 400 passes through the cable, it can be placed on the end of the sleeve, that is, the cover 400 completes the sealing of the insulation cavity. It should be noted that the second housing 222 is located on one side inside the insulation cavity, while the filter assembly 210 is located on one side outside the insulation cavity.

[0064] It should be understood that through holes can be provided in the cover 400 in advance for the conduit 221 to pass through; threaded holes can be provided in the cover 400 in advance for screw fixation. Of course, threaded holes can also not be provided in advance, and self-tapping screws can also be used to achieve the connection.

[0065] It can be understood that the cable terminal 300 can also be provided with a protective cover 310, and the connection device 200 is arranged inside the protective cover 310.

[0066] In an installation embodiment, the semi-circular protective cover 310 can be placed on the cover 400, and the connection device 200 can be placed inside the protective cover 310 to play a protective role. Specifically, it can prevent large solids from falling into the connection device 200 and can also prevent external liquids from entering the connection device 200. For example, in rainy weather, rainwater may collect on the surface of the outdoor cable terminal.

[0067] In a cable terminal according to an embodiment of the present invention, the cable terminal is installed with the above-mentioned device for pressure balance inside the cable terminal.

[0068] Taking a cable terminal 300 as an example, an insulation cavity is provided inside the cable terminal 300, and the insulation cavity is filled with an insulating material. Specifically, the cable terminal 300 includes a cable 320 and a sleeve 330 sleeved outside the cable 320. Since the original insulation layer of the cable 320 inside the sleeve 330 has been peeled off, an insulating material must be refilled between the cable 320 and the sleeve 330, and the gap between the cable 320 and the sleeve 330 is the insulation cavity.

[0069] The insulating material filled in the insulation cavity is used to maintain the insulation of the cable 320. The insulating material can be selected from silicone oil, polyisobutylene or silicone gel and added by perfusion. Generally speaking, the cable terminal 300 is vertically arranged, that is, the insulation cavity is distributed vertically. After the insulating material is filled into the insulation cavity, it occupies the bottom of the insulation cavity. The insulating material filled in the insulation cavity will keep its liquid level height at 70% - 80% of the height of the insulation cavity, and the remaining part of the insulation cavity can be used for the installation of the membrane body 100.

[0070] The membrane body 100 can be made of a flexible material, which can change the shape of the membrane body 100 to achieve a variable volume of the first chamber. The first chamber surrounded by the membrane body 100 occupies the remaining part of the insulation chamber, that is, the insulation chamber is jointly occupied by the insulator and the first chamber. No other solids or liquids are filled in the first chamber, so the first chamber is generally filled with air.

[0071] It should be emphasized that the membrane body 100 is installed in the insulation chamber, and the first chamber surrounded by the membrane body 100 needs to be in a non-connected state with the insulation chamber. The connection device 200 is used to be installed on the cable terminal 300. The connection device 200 has a connected first end and a second end. The connection device 200 is connected to the membrane body 100, and the second end of the connection device 200 is connected to the first chamber. The first end of the connection device 200 is used to connect to the external environment.

[0072] The first chamber is kept connected to the external environment through the connection device 200. When the volume of the first chamber changes, for example, when the volume of the first chamber decreases, the air in the first chamber is squeezed out through the connection device 200 and escapes to the external environment. Therefore, the pressure in the first chamber is in a balanced state. If the volume of the first chamber increases, the air in the external environment can re-enter the first chamber through the connection device 200 to prevent the pressure in the first chamber from decreasing. Therefore, the pressure in the first chamber is maintained near the normal atmospheric pressure.

[0073] The change in the volume of the first chamber is caused by the change in the volume of the insulator. When the cable terminal 300 is working, the heat effect generated by the current radiates into the insulation chamber, and the insulator expands due to heat and its volume increases. Since the volume of the insulation chamber is fixed, the insulator will squeeze the membrane body 100, and the deformation of the membrane body 100 causes the volume of the first chamber to decrease. Since the working current of the cable terminal 300 is not constant, the heat generated in different time periods changes. Coupled with the change in the temperature of the external environment, the temperature of the insulator also changes. So when the temperature of the insulator drops, the volume of the insulator will shrink again, forming a cavity with negative pressure in the insulation chamber, and these cavities will be filled by the membrane body 100, that is, the volume of the first chamber increases.

[0074] It should be understood that the change in the volume of the insulator in the insulation chamber is adjusted by changing the volume of the first chamber, so that the pressure in the insulation chamber is maintained at a constant value, generally the pressure is maintained near the atmospheric pressure. Since the insulation chamber and the first chamber are not connected, pollutants such as moisture and particulate matter in the external environment will not enter the insulation chamber to contaminate the insulator, and the insulator will not leak to the external environment either. The insulation performance of the cable terminal 300 is guaranteed, and the cable terminal 300 can operate stably and safely.

[0075] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A device for balancing pressure in a cable terminal, characterized in that: include: A membrane body (100), the membrane body (100) enclosing a first chamber with a variable volume, the membrane body (100) being used for being installed in an insulating cavity of a cable terminal; A communication device (200), the communication device (200) having a first end and a second end in communication, the communication device (200) being connected to the membrane body (100), and the second end of the communication device (200) being in communication with the first chamber, and the first end of the communication device (200) being used for communicating with an external environment; The communication device (200) comprises a filter component (210) and a conduction component (220), the first chamber is communicated with one end of the conduction component (220), the filter component (210) is connected with the other end of the conduction component (220), and the filter component (210) is used to communicate with the external environment; The conduction component (220) comprises a conduit (221) and a second shell (222); the second shell (222) is arranged in the first chamber; the second shell (222) has a second chamber; the second shell (222) is provided with a third through hole (223); the first chamber and the second chamber are communicated with each other through the third through hole (223); one end of the conduit (221) is communicated with the filter component (210); the other end of the conduit (221) extends into the second chamber; The second chamber is filled with a barrier liquid (224), the liquid level of the barrier liquid (224) is higher than the port of the conduit (221), and the liquid level of the barrier liquid (224) is lower than the third through hole (223); The filter assembly (210) comprises a first shell (211) and filter material (212); the first shell (211) has a filter cavity; the first shell (211) is provided with a first through hole (213); the first through hole (213) connects the filter cavity with the external environment; the first shell (211) is provided with a second through hole (214); the second through hole (214) connects the filter cavity with the conduction assembly (220); the filter material (212) is filled in the filter cavity and is located between the first through hole (213) and the second through hole (214); the filter cavity is filled with the granular filter material; the first shell (211) is provided with a plurality of the second through holes (214); the inner diameter of the second through hole (214) is smaller than the size of the filter material.

2. The device for balancing pressure in a cable terminal according to claim 1, characterized in that: The first through hole (213) is arranged at the top of the first shell (211), and the second through hole (214) is arranged at the bottom of the first shell (211).

3. The device for balancing pressure in a cable terminal according to claim 1, characterized in that: A third shell (225) is provided between the conduit (221) and the filter assembly (210); the third shell (225) has a third chamber; the third chamber is in communication with the filter assembly (210); and the third chamber is in communication with the second chamber via the conduit (221).

4. The device for balancing pressure in a cable terminal according to claim 1 or 3, characterized in that: The conduction component (220) further includes a first connecting plate (226) and a second connecting plate (227); the conduit (221) is disposed on a side surface of the first connecting plate (226); the other side surface of the first connecting plate (226) is connected to the filter component (210); the second shell (222) is disposed on a side surface of the second connecting plate (227); the other side surface of the second connecting plate (227) is connected to the first connecting plate (226); the first connecting plate (226) is located on the opposite side of the second connecting plate (227); and the conduit (221) extends into the second chamber.

5. A cable terminal, characterized in that: The cable terminal is equipped with the device for balancing the pressure in the cable terminal according to any one of claims 1 to 4.

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