A medium voltage power transmission cable with gas tightness for explosive atmosphere

Abstract

The present invention discloses an explosive environment airtight medium-voltage power transmission cable, which relates to the technical field of power cables and comprises a central conductor, wherein the outer side of the central conductor is tightly coated with internal conductor insulation, the outer side of the internal conductor insulation is tightly coated with an insulating conductor shield, the outer sides of the plurality of insulating conductor shields are jointly coated with steel belt armor, the outer side of the steel belt armor is tightly coated with a PVC protective sleeve, and the outer side of the PVC protective sleeve is provided with an external telescopic expansion protection mechanism. The present invention drives the flame-retardant metal mesh to expand outwards through the characteristic of thermal expansion of the flame-retardant expansion rubber strip, and constructs a fire barrier on the outer side of the cable through the flame-retardant metal mesh to ensure that even if an open flame occurs inside the cable, the combustible gas outside the cable will not be ignited, thereby effectively improving the overall fire and explosion resistance of the cable, and at the same time, by actively increasing the outer diameter of the fault location, it is prevented that the high voltage inside the cable breaks through the protective layer and ignites the external combustible gas, thereby improving the overall protection performance of the cable.

Description

Technical Field

[0001] The present invention relates to the technical field of power cables, and in particular to an explosive environment airtight medium-voltage power transmission cable. Background Art

[0002] The circuit generates a circuit or electric spark, but it is not enough to ignite the surrounding flammable and explosive gases. Such a circuit is an explosion-proof safety circuit, and the cable used is an explosion-proof cable, which is characterized by low capacitance, not easy to store charge, good shielding performance and anti-static performance. Compared with ordinary cables, explosion-proof cables have high temperature resistance, corrosion resistance and current carrying capacity than ordinary cables. The fire-resistant, heat-resistant and explosion-proof characteristics of explosion-proof cables can extend their use time in the event of a fire, and can prevent flammable and explosive mixtures from contacting electrical components and possibly causing explosions. Ordinary cables cannot meet the requirements of use in special flammable and explosive environments;

[0003] Explosion-proof cables are required in places with explosive hazards, such as chemical companies, gas stations, gas stations, oil companies, and other places with extremely high safety requirements.

[0004] A Chinese patent discloses a flame-retardant explosion-proof cable with application number 202320412423.9. The patent can improve the flame-retardant effect through the combined design of two flame-retardant layers, thereby improving the overall flame-retardant performance of the cable. The design of the compression-resistant parts can improve the compression resistance of the cable, avoiding the conductor breakage and wire core bulging caused by external impact or collision, which is conducive to normal use and has broad market prospects.

[0005] However, currently, explosion-proof cables are mostly protected by the physical and chemical properties of their protective outer sheath during use. When a fire occurs during the use of the cable, it tends to spread from the inside of the cable to the outside, which can cause flammable gases in the external environment to ignite accidents when the cable fails, thereby reducing the safety of cable use. Summary of the invention

[0006] The present invention provides an explosive environment airtight medium-voltage power transmission cable, which can effectively solve the problem that the explosion-proof cable proposed in the above background technology is mostly protected by the physical and chemical properties of its protective outer sheath during use, and when a fire occurs during the use of the cable, it mostly spreads from the inside of the cable to the outside, so that when the cable fails, the combustible gas in the external environment will be ignited to cause an accident, thereby reducing the safety of the cable.

[0007] To achieve the above object, the present invention provides the following technical solution: an explosive atmosphere airtight medium-voltage power transmission cable, comprising a central conductor, the outer side of the central conductor is tightly coated with an inner conductor insulation, the outer side of the inner conductor insulation is tightly coated with an insulated conductor shield, the outer sides of the plurality of insulated conductor shields are jointly coated with a steel belt armor, and the outer side of the steel belt armor is tightly coated with a PVC protective sleeve;

[0008] An external telescopic expansion protection mechanism is arranged outside the PVC protective sleeve, and the external telescopic expansion protection mechanism is used to actively protect the outside of the cable;

[0009] The external telescopic expansion protection mechanism includes an elastic silicone sleeve;

[0010] An elastic silicone sleeve is arranged outside the PVC protective sleeve, and the elastic silicone sleeve is tightly covered with an elastic protective sleeve outside;

[0011] The outer side of the PVC protective sleeve is symmetrically arranged with internal installation rubber strips along the circumferential direction, and a flame-retardant metal thin mesh is bonded between two adjacent internal installation rubber strips along the circumferential direction. A flame-retardant expansion rubber strip is bonded to the inner side of the corresponding flame-retardant metal thin mesh between the corresponding two internal installation rubber strips on the outer side of the PVC protective sleeve, and ceramic protective sheets are staggered and inlaid inside the flame-retardant expansion rubber strips;

[0012] The elastic silicone sleeve is filled with a sponge filling strip at a gap corresponding to the outer side of the flame-retardant metal thin mesh, and the sponge filling strip is evenly filled with resin particles.

[0013] According to the above technical solution, elastic elliptical holes are evenly and equidistantly penetrated on the edge of the end face of the elastic protective sleeve along the circumferential direction, the outer side of the elastic protective sleeve is tightly covered with an outer ring rubber protective sleeve, and narrow fracture grooves are evenly and equidistantly opened on the outer side of the outer ring rubber protective sleeve along the circumferential direction, and wear-resistant rubber sheets are evenly and equidistantly bonded to the outer side of the outer ring rubber protective sleeve along the circumferential direction.

[0014] According to the above technical solution, the central conductor is distributed along the inner circumference of the steel belt armor, and the outer side of the PVC protective sleeve is tightly fitted to the inner wall of the steel belt armor.

[0015] According to the above technical solution, the internal installation rubber strips are arranged in sections at equal distances along the axial direction, and the flame-retardant metal mesh is folded in the same direction during the installation process.

[0016] According to the above technical solution, the inner arc surface of the flame retardant expansion rubber strip is tightly slidably fitted with the outer side of the PVC protective sleeve, and the ceramic protective sheets are alternately distributed in multiple layers along the inside of the flame retardant expansion rubber strip.

[0017] According to the above technical solution, there are pores inside the sponge filling strip, and the resin particles will melt in an environment with a temperature higher than the normal working temperature of the cable.

[0018] According to the above technical solution, an internal expansion and telescopic support and protection mechanism is arranged inside the steel belt armor, and the internal expansion and telescopic support and protection mechanism utilizes its own physical and chemical properties of thermal expansion and contraction to make the cable have toughness when running in different temperature environments;

[0019] The internal expansion and telescopic support and protection mechanism includes a central support bar;

[0020] A central support strip is evenly and equidistantly arranged in the middle of the inner side of the steel belt armor, a central guide block is fixedly connected to the middle of the inner side of the central support strip, and a guide hole is evenly and equidistantly opened through the end surface of the central guide block, and mounting end blocks are embedded and installed at both ends of the inner cavity of the central support strip, and an elastic plastic column is fixedly connected to the end surface of the mounting end block at a position corresponding to the inner position of the guide hole;

[0021] A limited fan-shaped capsule is fixedly connected to the side of the central support bar corresponding to the gap on the side of the insulated conductor shield, a central adjustment box is embedded and installed at the middle position of the inner side of the limited fan-shaped capsule, sliding top covers are bonded to both ends of the central adjustment box, a central limiting plate is fixedly installed in the middle of the inner side of the central adjustment box, a telescopic expansion strip is embedded and installed in the middle of the inner side of the central limiting plate, and compression springs are fixedly connected at the outer positions of the telescopic expansion strips on both sides of the central limiting plate;

[0022] The positions of the cavities at both ends of the center adjustment box inside the limiting fan-shaped bag are filled with compressed rubber balls, the ends of the limiting fan-shaped bag are fixedly connected to the connecting fan-shaped blocks, and the ends of the center support strips are fixedly connected to the connecting center rubber blocks.

[0023] According to the above technical solution, the outer arc surface of the central support bar is tightly fitted with the outer side of the insulated conductor shield, and the elastic plastic column and the guide hole are correspondingly fitted with each other.

[0024] According to the above technical solution, a gap is left between the side of the sliding top cover and the inner wall of the limiting fan-shaped bag, and the telescopic expansion strip will expand and contract in the length direction when the temperature changes. The telescopic expansion strip and the end of the compression spring are fixedly connected to the corresponding sliding top cover.

[0025] According to the above technical solution, two axially adjacent limiting sector-shaped bags are connected by connecting sector-shaped blocks, and two axially adjacent central support bars are connected by connecting central rubber blocks.

[0026] Compared with the prior art, the present invention has the following beneficial effects: the present invention has a scientific and reasonable structure and is safe and convenient to use:

[0027] 1. An external telescopic expansion protection mechanism is provided. Through the mutual cooperation between the components inside the external telescopic expansion protection mechanism, the active protection process when a fault occurs inside the cable is optimized. Through the mutual cooperation between the flame-retardant metal thin mesh and the flame-retardant expansion rubber strip, when the cable is overheated due to a fault, the flame-retardant expansion rubber strip expands due to the heat, and the flame-retardant metal thin mesh is driven to expand outward, so as to build a fire barrier on the outside of the cable through the flame-retardant metal thin mesh to ensure that even if an open flame occurs inside the cable, the combustible gas outside the cable will not be ignited, thereby effectively improving the overall fire and explosion resistance of the cable. At the same time, by actively increasing the outer diameter of the fault location, it is prevented that the high voltage inside the cable breaks through the protective layer and ignites the external combustible gas, thereby further improving the overall protection performance of the cable;

[0028] At the same time, the elastic silicone sleeve, the elastic protective sleeve and the outer rubber protective sleeve cooperate with each other to provide flexible protection for the outer side of the cable, so that the outer side of the cable will not be significantly damaged by slight squeezing and friction, thereby ensuring the integrity of the internal structure of the cable and improving the flexible protection performance of the outer side of the cable. At the same time, the structural strength of the outer protective layer of the cable is adjusted through the elastic elliptical hole and the fracture narrow groove to ensure that the elastic silicone sleeve and the elastic protective sleeve can expand outward over a large range when high pressure is generated inside the cable due to expansion, and when the expansion amount inside the cable reaches the threshold, the outer rubber protective sleeve can actively rupture to release pressure, effectively preventing the internal fault of the cable from spreading along the axial and radial directions of the cable and increasing the difficulty of cable maintenance, and further optimizing the active protection process of the cable;

[0029] In addition, through the splicing structural design of flame-retardant metal thin mesh and flame-retardant expansion rubber strip, the faults inside the cable are limited, ensuring that the damaged area of ​​the cable can be quickly replaced during the later maintenance process. At the same time, through the staggered filling arrangement of ceramic protective sheets and resin particles, while intercepting external sharp puncture damage, the gaps generated during the expansion process can be sealed by the molten resin particles while the flame-retardant expansion rubber strip expands, and the fault site is re-sealed by the re-condensation of the resin after the temperature drops, ensuring that the cable can remain sealed throughout the entire fault process, effectively preventing the harmful gases generated during the fault process from spreading at will, and improving the overall environmental performance of the cable.

[0030] 2. An internal expansion telescopic support and protection mechanism is provided. Through the mutual cooperation between the internal components of the internal expansion telescopic support and protection mechanism, the protection process of the power cable during use is optimized. Through the mutual cooperation between the central support bar and the internal structures of the limiting fan-shaped bag, the internal structure of the cable is limited and isolated, which effectively prevents the internal structure from shifting when the cable is crushed and bent during use. The reverse elastic force of the elastic plastic column after bending and the reverse elastic force of the telescopic expansion rubber strip after passive compression are used to actively reset the internal structure and overall shape of the cable after the force squeezing the outside of the cable is removed, thereby effectively improving the overall stability of the internal structure of the cable;

[0031] At the same time, the thermal expansion and contraction characteristics of the expansion strip are utilized, so that when the cable is used in a high temperature environment, the compressed rubber ball will soften when heated, so as to increase the overall toughness of the cable. When the cable is used in a low temperature environment, the expansion strip and the sliding top cover can be contracted and moved, and then the gap between the compressed rubber balls can be increased to enable them to move when the cable is bent, so as to ensure that the cable can maintain good toughness when working in a cold environment, effectively avoid the cable from being broken when squeezed by external force during use, and further improve the comprehensive performance of the cable.

[0032] To summarize, through the mutual cooperation between the components inside the external telescopic expansion protection mechanism and the internal telescopic expansion support protection mechanism, and through the combined structural design of the inside and outside of the cable, the cable can be actively deformed through the extrusion and bending of the central support bar and the internal structure of the limiting fan-shaped bag during normal use, ensuring that the cable can return to its original state after the external extrusion force is removed, and when a high-temperature fault occurs inside the cable, the outside of the cable can be actively protected through the deformation of the flame-retardant metal mesh and the flame-retardant expansion rubber strip, thereby effectively preventing the surrounding combustible gases from being ignited when the cable fails, thereby effectively improving the explosion-proof performance and safety of use of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0034] In the attached picture:

[0035] Figure 1 It is a schematic diagram of the structure of the present invention;

[0036] Figure 2 It is a structural schematic diagram of the end face of the present invention;

[0037] Figure 3 It is a structural schematic diagram of the external telescopic expansion protection mechanism of the present invention;

[0038] Figure 4 It is a schematic diagram of the structure of the installation of the flame retardant expansion rubber strip of the present invention;

[0039] Figure 5 It is a structural schematic diagram of the internal expansion and telescopic support and protection mechanism of the present invention;

[0040] Figure 6 It is a structural schematic diagram of the installation of the center guide block of the present invention;

[0041] Figure 7 It is a schematic diagram of the structure of the installation of the elastic plastic column of the present invention;

[0042] Figure 8 The present invention Figure 7 A schematic diagram of the enlarged structure of region A;

[0043] Numbers in the figure: 1. Center conductor; 2. Inner conductor insulation; 3. Insulated conductor shield; 4. Steel tape armor; 5. PVC protective cover;

[0044] 6. External telescopic expansion protection mechanism; 601. Elastic silicone sleeve; 602. Elastic protective sleeve; 603. Elastic elliptical channel; 604. Outer ring rubber protective sleeve; 605. Fracture narrow groove; 606. Wear-resistant rubber sheet; 607. Internal installation rubber strip; 608. Flame-retardant metal thin mesh; 609. Flame-retardant expansion rubber strip; 610. Ceramic protective sheet; 611. Sponge filling strip; 612. Resin particles;

[0045] 7. Internal expansion telescopic support and protection mechanism; 701. Center support strip; 702. Center guide block; 703. Guide fine hole; 704. Mounting end block; 705. Elastic plastic column; 706. Limiting fan-shaped bag; 707. Center adjustment box; 708. Sliding top cover; 709. Center limiting plate; 710. Telescopic expansion rubber strip; 711. Compression spring; 712. Compression rubber ball; 713. Connecting fan-shaped block; 714. Connecting center rubber block. DETAILED DESCRIPTION

[0046] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0047] Example: Figure 1-8As shown, the present invention provides a technical solution, an explosive atmosphere airtight medium-voltage power transmission cable, comprising a central conductor 1, the outer side of the central conductor 1 is tightly coated with an inner conductor insulation 2, the outer side of the inner conductor insulation 2 is tightly coated with an insulating conductor shield 3, the outer sides of multiple insulating conductor shields 3 are jointly coated with a steel belt armor 4, the outer side of the steel belt armor 4 is tightly coated with a PVC protective sleeve 5, the central conductor 1 is distributed along the inner circumference of the steel belt armor 4, and the outer side of the PVC protective sleeve 5 is tightly fitted with the inner wall of the steel belt armor 4;

[0048] An external telescopic expansion protection mechanism 6 is arranged outside the PVC protective sleeve 5. The external telescopic expansion protection mechanism 6 is used to actively protect the outside of the cable and to protect the outside of the cable fault by actively adjusting the outer diameter of the cable.

[0049] The external telescopic expansion protection mechanism 6 includes an elastic silicone sleeve 601, an elastic protection sleeve 602, an elastic elliptical channel 603, an outer ring rubber protection sleeve 604, a fracture narrow groove 605, a wear-resistant rubber sheet 606, an internal installation rubber strip 607, a flame-retardant metal thin mesh 608, a flame-retardant expansion rubber strip 609, a ceramic protection sheet 610, a sponge filling strip 611 and resin particles 612;

[0050] An elastic silicone sleeve 601 is arranged on the outside of the PVC protective sleeve 5, and an elastic protective sleeve 602 is tightly covered on the outside of the elastic silicone sleeve 601, and an elastic elliptical hole 603 is evenly and equidistantly penetrated through the edge of the end face of the elastic protective sleeve 602 along the circumferential direction, and an outer ring rubber protective sleeve 604 is tightly covered on the outside of the elastic protective sleeve 602, and a fracture narrow groove 605 is evenly and equidistantly opened on the outside of the outer ring rubber protective sleeve 604 along the circumferential direction, and a wear-resistant rubber sheet 606 is evenly and equidistantly bonded to the outside of the outer ring rubber protective sleeve 604 along the circumferential direction;

[0051] The outer side of the PVC protective sleeve 5 is symmetrically arranged with internal installation rubber strips 607 along the circumferential direction, and a flame retardant metal thin mesh 608 is bonded between two adjacent internal installation rubber strips 607 along the circumferential direction. The internal installation rubber strips 607 are arranged in sections at equal distances along the axial direction. The flame retardant metal thin mesh 608 is folded in the same direction during the installation process, and the flame retardant metal thin mesh 608 can be plastically deformed;

[0052] A flame retardant expansion rubber strip 609 is bonded to the inner side of the flame retardant metal thin mesh 608 between the two internal installation rubber strips 607 on the outer side of the PVC protective sleeve 5, and ceramic protective sheets 610 are staggered and inlaid inside the flame retardant expansion rubber strip 609. The flame retardant expansion rubber strip 609 can be elastically deformed, and the inner arc surface of the flame retardant expansion rubber strip 609 is tightly slidably fitted with the outer side of the PVC protective sleeve 5, and the ceramic protective sheets 610 are alternately distributed in multiple layers along the inner side of the flame retardant expansion rubber strip 609;

[0053] The gaps on the outside of the flame-retardant metal mesh 608 are filled with sponge filling strips 611 inside the elastic silicone sleeve 601, and the inside of the sponge filling strips 611 are uniformly filled with resin particles 612. There are a large number of pores inside the sponge filling strips 611, and the resin particles 612 will gradually melt in a temperature environment higher than the normal operation of the cable. The mutual cooperation between the components inside the external telescopic expansion protection mechanism 6 optimizes the active protection process when a fault occurs inside the cable. The mutual cooperation between the flame-retardant metal mesh 608 and the flame-retardant expansion rubber strip 609 allows the flame-retardant metal mesh 608 to expand outwards due to the heat expansion characteristics of the flame-retardant expansion rubber strip 609 when the cable is overheated due to a fault, so as to build a fire barrier on the outside of the cable through the flame-retardant metal mesh 608 to ensure that even if an open flame occurs inside the cable, the combustible gas outside the cable will not be ignited, thereby effectively improving the overall fire and explosion resistance of the cable. At the same time, by actively increasing the outer diameter of the fault location, it is prevented that the high voltage inside the cable breaks through the protective layer and ignites the external combustible gas, thereby further improving the overall protection performance of the cable.

[0054] At the same time, the elastic silicone sleeve 601, the elastic protective sleeve 602 and the outer ring rubber protective sleeve 604 cooperate with each other to provide flexible protection for the outer side of the cable, so that the outer side of the cable will not be significantly damaged by slight squeezing and friction, thereby ensuring the integrity of the internal structure of the cable and improving the flexible protection performance of the outer side of the cable. At the same time, the structural strength of the protective layer on the outer side of the cable is adjusted by the elastic elliptical channel 603 and the fracture narrow groove 605 to ensure that when the internal pressure of the cable is generated due to expansion, the elastic silicone sleeve 601 and the elastic protective sleeve 602 can expand outward over a large range, and when the expansion amount inside the cable reaches a threshold, the outer ring rubber protective sleeve 604 can actively rupture to release pressure, effectively preventing the fault inside the cable from spreading along the axial and radial directions of the cable to increase the difficulty of cable maintenance, and further optimizing the active protection process of the cable;

[0055] Furthermore, the structural design of the splicing of the flame-retardant metal thin mesh 608 and the flame-retardant expansion rubber strip 609 limits the fault inside the cable, ensuring that the damaged area of ​​the cable can be quickly replaced during the later maintenance process. At the same time, the staggered filling arrangement of the ceramic protective sheet 610 and the resin particles 612 can intercept external sharp puncture damage while the flame-retardant expansion rubber strip 609 expands and the gap generated during the expansion process can be blocked by the molten resin particles 612. After the temperature drops, the fault location is re-sealed by the re-condensation of the resin, ensuring that the cable can remain sealed during the entire fault process, effectively preventing the harmful gas generated during the fault process from spreading at will, and improving the overall environmental performance of the cable.

[0056] An internal expansion and telescopic support and protection mechanism 7 is arranged inside the steel belt armor 4. The internal expansion and telescopic support and protection mechanism 7 utilizes its own physical and chemical properties of thermal expansion and contraction to make the cable have toughness when running in different temperature environments;

[0057] The internal expansion telescopic support and protection mechanism 7 includes a central support strip 701, a central guide block 702, a guide hole 703, a mounting end block 704, an elastic plastic column 705, a limiting fan-shaped bag 706, a central adjustment box 707, a sliding top cover 708, a central limiting plate 709, a telescopic expansion rubber strip 710, a compression spring 711, a compression rubber ball 712, a connecting fan-shaped block 713 and a connecting central rubber block 714;

[0058] A central support bar 701 is evenly and equidistantly arranged in the middle of the inner side of the steel belt armor 4, a central guide block 702 is fixedly connected to the middle of the inner side of the central support bar 701, and a guide hole 703 is evenly and equidistantly opened through the end face of the central guide block 702, and mounting end blocks 704 are embedded and installed at both ends of the inner cavity of the central support bar 701, and an elastic plastic column 705 is fixedly connected at the position of the end face of the mounting end block 704 corresponding to the inner position of the guide hole 703, the outer arc surface of the central support bar 701 is tightly fitted with the outer side of the insulated conductor shield 3, the central support bar 701 can be elastically deformed, the elastic plastic column 705 and the guide hole 703 are correspondingly fitted, and the elastic plastic column 705 can slide along the inside of the guide hole 703;

[0059] A limited fan-shaped capsule 706 is fixedly connected to the side gap of the insulating conductor shield 3 on the side of the central support bar 701, and a central adjustment box 707 is embedded and installed in the middle position of the inner side of the limited fan-shaped capsule 706. Both ends of the central adjustment box 707 are bonded with sliding top covers 708, and a central limiting plate 709 is fixedly installed in the middle of the inner side of the central adjustment box 707. A telescopic expansion rubber strip 710 is embedded and installed in the middle of the inner side of the central limiting plate 709. Compression springs 711 are fixedly connected to the outer positions of the telescopic expansion rubber strip 710 on both sides of the central limiting plate 709 corresponding to the outer sides of the telescopic expansion rubber strip 710. Both ends of the central adjustment box 707 can be elastically retracted, and a gap is left between the side of the sliding top cover 708 and the inner wall of the limited fan-shaped capsule 706. The telescopic expansion rubber strip 710 will expand and contract in the length direction when the temperature changes, and the ends of the telescopic expansion rubber strip 710 and the compression spring 711 are fixedly connected to the corresponding sliding top covers 708.

[0060] The cavities at both ends of the corresponding central adjustment box 707 in the limiting fan-shaped capsule 706 are filled with compressed rubber balls 712, the ends of the limiting fan-shaped capsule 706 are fixedly connected with connecting fan-shaped blocks 713, and the ends of the central support strips 701 are fixedly connected with connecting central rubber blocks 714. The compressed rubber balls 712 can move independently of each other, and the two axially adjacent limiting fan-shaped capsules 706 are connected by connecting fan-shaped blocks 713, and the two axially adjacent central support strips 701 are connected by connecting central rubber blocks 714. The components inside the internal expansion telescopic support protection mechanism 7 are connected. The mutual cooperation between the central support bar 701 and the internal structures of the limiting fan-shaped bag 706 optimizes the protection process during the use of the power cable. The internal structure of the cable is limited and isolated through the mutual cooperation between the central support bar 701 and the internal structures of the limiting fan-shaped bag 706, which effectively prevents the internal structure from shifting when the cable is crushed and bent during use. The reverse elastic force of the elastic plastic column 705 after bending and the reverse elastic force of the telescopic expansion rubber strip 710 after passive compression are used to actively reset the internal structure and overall shape of the cable after the force squeezing the outer side of the cable is removed, thereby effectively improving the overall stability of the internal structure of the cable.

[0061] At the same time, the thermal expansion and contraction characteristics of the telescopic expansion strip 710 are utilized, so that when the cable is used in a high temperature environment, the characteristic of the compressed rubber ball 712 that it will soften when heated is utilized to increase the overall toughness of the cable. When the cable is used in a low temperature environment, the telescopic expansion strip 710 and the sliding top cover 708 can be contracted and moved, and then the gap between the compressed rubber balls 712 can be increased to enable them to move when the cable is bent, thereby ensuring that the cable can maintain good toughness when working in a cold environment, effectively avoiding the cable from breaking when squeezed by external force during use, and further improving the comprehensive performance of the cable.

[0062] Working principle and use process of the present invention: In the actual application process of the present invention, during the use of the cable, it is necessary to first connect the central conductor 1 to a suitable position, and protect the outer side of the central conductor 1 through the internal conductor insulation 2 and the insulated conductor shield 3 to ensure the normal operation of the cable, and bundle the central conductor 1 through the steel belt armor 4 and the PVC protective sleeve 5 to further improve the overall protection performance of the cable;

[0063] When a short circuit occurs in the cable, abnormal heating will occur inside the cable, and the temperature inside the cable will continue to rise. The heat outside the cable will be transferred to the inside of the flame-retardant expansion strip 609 through the steel belt armor 4 and the PVC protective sheath 5. When the temperature inside the flame-retardant expansion strip 609 reaches its expansion condition, the flame-retardant expansion strip 609 will begin to expand from the inside to the outside. At the same time, the flame-retardant metal mesh 608 can be tightly wrapped around the outside of the flame-retardant expansion strip 609 through the internal installation strip 607 for limiting. After the flame-retardant expansion strip 609 expands, the flame-retardant metal mesh 608 will expand outward, thereby expanding the outer diameter of the cable as a whole, so as to increase the distance between the heating point inside the cable and the outside of the cable, so as to prevent the fire source inside the cable from contacting the external combustible gas.

[0064] In addition, during the gradual expansion of the flame-retardant metal mesh 608, heat is transferred to the sponge filling strip 611 and the side of the resin particles 612. The internal gap of the elastic silicone sleeve 601 can be filled through the sponge filling strip 611 to prevent the flame-retardant metal mesh 608 from shaking during use. When the temperature of the resin particles 612 reaches the melting temperature, the internal gap of the elastic silicone sleeve 601 can be filled with molten resin to ensure that the cable can still maintain good air tightness after thermal expansion.

[0065] During normal use of the cable, the flame-retardant metal mesh 608 and the sponge filling strip 611 can be bundled and limited by the elastic silicone sleeve 601, and the outer side of the cable can be elastically protected by the elastic protective sleeve 602, so that the outer side of the cable can maintain good elastic and retractable performance, and the elastic elliptical channel 603 further enhances the overall retractability of the elastic protective sleeve 602, and then the outermost side of the cable is protected by the outer rubber protective sleeve 604, and the overall wear resistance of the cable is enhanced by the wear-resistant film 606 to ensure that the cable has better wear resistance during transportation and pulling, and the structural strength of part of the outer ring of the outer rubber protective sleeve 604 is reduced by the broken narrow groove 605, so that when the inside of the cable expands outward, it can break outward from the broken narrow groove 605, and the inside of the cable can also be protected by the ceramic protective sheet 610, so that when the cable is punctured by a sharp object, it can be intercepted by the ceramic protective sheet 610 to prevent the puncture damage of the cable from directly damaging the inside of the PVC protective sleeve 5 and affecting the normal use of the cable;

[0066] When the inside of the cable needs to be protected during use, the central support bar 701 and the limiting fan-shaped bag 706 are installed inside the steel belt armor 4 by connecting the fan-shaped block 713 and the connecting center rubber block 714, and then the elastic plastic column 705 is symmetrically inserted into the two ends of the central guide block 702 by installing the end block 704. When the cable is bent by external extrusion, the elastic plastic column 705 can be driven to bend synchronously while the cable is bent, and the end of the elastic plastic column 705 can slide along the inside of the guide hole 703. When the external force on the cable is removed, the cable is reset by the resilience of the multiple elastic plastic columns 705, thereby effectively improving the bending resistance of the cable.

[0067] In the process of the cable being squeezed and bent and reset, it is also necessary to prevent the internal components of the cable from shifting. When the internal temperature of the cable is continuously higher than the ambient temperature, the compressed rubber ball 712 and the telescopic expansion rubber strip 710 will soften due to the physical and chemical properties of their own materials after being heated, so as to ensure that the internal components of the limiting fan-shaped capsule 706 can bend synchronously with the cable, and the gaps on the side surfaces of the insulated conductor shield 3 are filled by the limiting fan-shaped capsule 706 and the compressed rubber ball 712, so as to effectively prevent the internal components of the cable from shifting after the cable is bent and reset.

[0068] When the cable as a whole operates in a low-temperature environment, the telescopic expansion strip 710 will gradually shrink axially in the low-temperature environment, and in the process of shrinking the telescopic expansion strip 710, it will simultaneously drive the two sliding top covers 708 to overcome the elastic force of the compression spring 711 and move closer to each other, thereby increasing the gap between the tightly fitted compression rubber balls 712, so that the compression rubber balls 712 can move inside the limiting fan-shaped bag 706, so that when the limiting fan-shaped bag 706 is squeezed, it can bend and deform through the movement of the compression rubber balls 712, thereby preventing the cable from bending and breaking due to hardening of the material when working in a low-temperature environment, thereby further improving the comprehensive performance of the cable.

[0069] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An explosive atmosphere gas-tight medium-voltage power transmission cable, comprising a central conductor (1), characterized in that: The outer side of the central conductor (1) is tightly covered with an inner conductor insulation (2), the outer side of the inner conductor insulation (2) is tightly covered with an insulating conductor shield (3), the outer sides of the plurality of insulating conductor shields (3) are jointly covered with a steel belt armor (4), and the outer side of the steel belt armor (4) is tightly covered with a PVC protective sleeve (5); An external telescopic expansion protection mechanism (6) is arranged outside the PVC protective sleeve (5), and the external telescopic expansion protection mechanism (6) is used to actively protect the outside of the cable; The external telescopic expansion protection mechanism (6) comprises an elastic silicone sleeve (601); An elastic silicone sleeve (601) is arranged outside the PVC protective sleeve (5), and an elastic protective sleeve (602) is tightly wrapped outside the elastic silicone sleeve (601); The outer side of the PVC protective sleeve (5) is provided with internal installation rubber strips (607) arranged symmetrically and equidistantly in the circumferential direction, a flame retardant metal thin mesh (608) is bonded between two adjacent internal installation rubber strips (607) in the circumferential direction, and a flame retardant expansion rubber strip (609) is bonded to the inner side of the corresponding flame retardant metal thin mesh (608) between the two corresponding internal installation rubber strips (607) on the outer side of the PVC protective sleeve (5), and ceramic protective sheets (610) are staggeredly inlaid inside the flame retardant expansion rubber strips (609); The gap inside the elastic silicone sleeve (601) corresponding to the outer side of the flame-retardant metal thin mesh (608) is filled with a sponge filling strip (611), and the inside of the sponge filling strip (611) is evenly filled with resin particles (612).

2. The explosive atmosphere airtight medium voltage power transmission cable according to claim 1, characterized in that: The elastic protective sleeve (602) has an elastic elliptical hole (603) extending uniformly and equidistantly through the edge of the end face along the circumferential direction; the elastic protective sleeve (602) is tightly covered with an outer ring rubber protective sleeve (604); the outer ring rubber protective sleeve (604) has fracture narrow grooves (605) uniformly and equidistantly provided along the circumferential direction; and the outer ring rubber protective sleeve (604) has a wear-resistant rubber sheet (606) bonded uniformly and equidistantly along the circumferential direction.

3. The explosive atmosphere airtight medium voltage power transmission cable according to claim 1, characterized in that: The central conductor (1) is distributed along the inner circumference of the steel strip armor (4), and the outer side of the PVC protective sleeve (5) is tightly fitted to the inner wall of the steel strip armor (4).

4. The explosive atmosphere airtight medium voltage power transmission cable according to claim 1, characterized in that: The internal installation rubber strips (607) are arranged in sections at equal intervals along the axial direction, and the flame-retardant metal thin mesh (608) is folded in the same direction during the installation process.

5. The explosive atmosphere airtight medium voltage power transmission cable according to claim 1, characterized in that: The inner arc surface of the flame-retardant expansion rubber strip (609) is tightly slidably fitted with the outer side of the PVC protective sleeve (5), and the ceramic protective sheets (610) are alternately distributed in multiple layers along the inside of the flame-retardant expansion rubber strip (609).

6. The explosive atmosphere airtight medium voltage power transmission cable according to claim 1, characterized in that: The sponge filling strip (611) has pores inside, and the resin particles (612) will melt in an environment with a temperature higher than that of the normal operation of the cable.

7. The explosive atmosphere airtight medium voltage power transmission cable according to claim 1, characterized in that: An internal expansion and telescopic support and protection mechanism (7) is arranged inside the steel belt armor (4). The internal expansion and telescopic support and protection mechanism (7) utilizes its own physical and chemical properties of thermal expansion and contraction to ensure that the cable has toughness when operating in different temperature environments; The internal expansion and telescopic support and protection mechanism (7) comprises a central support bar (701); A central support strip (701) is evenly and equidistantly arranged in the middle of the inner side of the steel strip armor (4); a central guide block (702) is fixedly connected to the middle of the inner side of the central support strip (701); guide fine holes (703) are evenly and equidistantly penetrated through the end surface of the central guide block (702); mounting end blocks (704) are embedded and installed at both ends of the inner cavity of the central support strip (701); and elastic plastic columns (705) are fixedly connected to the end surfaces of the mounting end blocks (704) at positions corresponding to the inner sides of the guide fine holes (703); A limited fan-shaped capsule (706) is fixedly connected to the side gap of the insulating conductor shield (3) on the side of the central support bar (701), a central adjustment box (707) is embedded and installed at the middle position of the inner side of the limited fan-shaped capsule (706), and sliding top covers (708) are bonded to both ends of the central adjustment box (707). A central limit plate (709) is fixedly installed in the middle of the inner side of the central adjustment box (707), and a telescopic expansion rubber strip (710) is embedded and installed in the middle of the inner side of the central limit plate (709), and compression springs (711) are fixedly connected at the outer positions of the telescopic expansion rubber strip (710) on both sides of the central limit plate (709); The cavities at both ends of the limiting fan-shaped bag (706) corresponding to the central adjustment box (707) are filled with compressed rubber balls (712), the ends of the limiting fan-shaped bag (706) are fixedly connected to connecting fan-shaped blocks (713), and the ends of the central support bar (701) are fixedly connected to connecting central rubber blocks (714).

8. The explosive atmosphere airtight medium voltage power transmission cable according to claim 7, characterized in that: The outer arc surface of the central support bar (701) is tightly fitted to the outer side of the insulated conductor shield (3), and the elastic plastic column (705) and the guide fine hole (703) are correspondingly fitted to each other.

9. The explosive atmosphere airtight medium voltage power transmission cable according to claim 7, characterized in that: A gap is left between the side of the sliding top cover (708) and the inner wall of the limiting fan-shaped bag (706); the telescopic expansion strip (710) will expand and contract in the length direction when the temperature changes; the ends of the telescopic expansion strip (710) and the compression spring (711) are fixedly connected to the corresponding sliding top cover (708).

10. The explosive atmosphere airtight medium voltage power transmission cable according to claim 7, characterized in that: Two axially adjacent limiting sector-shaped bags (706) are connected via a connecting sector-shaped block (713), and two axially adjacent central support bars (701) are connected via a connecting central rubber block (714).

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