A moisture resistant, impermeable, low voltage crosslinked polyethylene insulated cable

Abstract

This invention relates to the field of cross-linked polyethylene (XLPE) insulated cable technology, and proposes a moisture-resistant and penetration-proof low-voltage XLPE insulated cable, comprising a conductor, a XLPE insulation layer, an inner sheath, an armor layer, and an outer sheath. It also includes a waterproof layer, an outer protective layer, a connecting sleeve, a sealing element, and a drying component. The waterproof layer is detachably disposed outside the outer sheath, and the outer protective layer is detachably disposed outside the waterproof layer. The connecting sleeve is detachably disposed between two adjacent protective layers. Multiple sealing rings are fixedly fitted onto the outer end of the outer protective layer. The sealing element provides secondary sealing for the gap between the connecting sleeve and the outer protective layer. The drying component is configured to seal the gap between the outer protective layer and the waterproof layer and absorb moisture entering the outer protective layer. This technical solution addresses the problems of reduced moisture resistance due to outer sheath damage, high maintenance costs, and lack of active moisture protection in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of cross-linked polyethylene insulated cable technology, specifically to a moisture-resistant and penetration-proof low-voltage cross-linked polyethylene insulated cable. Background Technology

[0002] Cross-linked polyethylene insulated power cables have been widely used in fixed installation scenarios in power distribution networks and industrial installations due to their excellent electrical insulation performance, high long-term allowable operating temperature, good mechanical strength and aging resistance. They cover various environments such as indoors, tunnels, cable trenches and direct burial. Armored cables can also be laid in mines, underground projects and other occasions that need to withstand mechanical external forces.

[0003] However, in practical engineering applications, when cross-linked polyethylene insulated cables are exposed to humid environments such as underground mines, underground pipe corridors, and coastal areas for a long time, the intrusion of moisture and water becomes the primary factor restricting the reliability and service life of the cables. Moisture may enter the cable through tiny gaps and damage in the outer sheath, leading to a decrease in insulation performance and causing electrical breakdown.

[0004] To improve the moisture resistance of cables, existing technologies often employ methods such as increasing the thickness of the outer sheath, setting a single waterproof layer, or using sealant at cable joints. However, once the outer sheath is damaged, its moisture resistance will decrease significantly. Furthermore, since the outer sheath is an integral structure, it needs to be replaced as a whole after damage, resulting in high maintenance costs. Moreover, existing technologies lack the ability to actively absorb and treat trace amounts of moisture that have penetrated in, which still poses safety hazards after long-term operation. Summary of the Invention

[0005] This invention proposes a moisture-resistant and penetration-proof low-voltage cross-linked polyethylene insulated cable to solve the problems of reduced moisture resistance due to outer sheath damage, high maintenance costs, and lack of active moisture protection in existing technologies.

[0006] The technical solution of the present invention is as follows: A moisture-resistant and penetration-proof low-voltage cross-linked polyethylene insulated cable includes a conductor, a cross-linked polyethylene insulation layer, an inner sheath, an armor layer, and an outer sheath, and further includes: A waterproof layer, which is detachably disposed on the outside of the outer sheath; An outer protective layer, wherein multiple outer protective layers are provided, and the outer protective layers are detachably disposed outside the waterproof layer; A connecting sleeve is detachably disposed between two adjacent outer protective layers. Multiple sealing rings are fixedly fitted on the outer side of the end of each outer protective layer, and the sealing rings are in contact with the inner wall of the connecting sleeve. A sealing element, disposed outside the outer protective layer, is used to provide a secondary seal for the gap between the connecting sleeve and the outer protective layer. The sealing element comprises: A movable ring, which is movably disposed outside the outer protective layer; A sealed airbag is detachably mounted on the movable ring, and the ends of the sealed airbag and the connecting sleeve contact each other to form a sealing structure. A drying component, disposed on the inner side of the end of the outer protective layer, is used to seal the gap between the outer protective layer and the waterproof layer and to absorb moisture entering the outer protective layer. The drying component includes: A closed ring is fixedly disposed at the inner end of the outer protective layer. The closed ring has a hollow structure and is filled with a desiccant. The closed ring has multiple ventilation holes at one end facing inward.

[0007] To enable the movement of the moving ring, an adjusting member is provided on the outside of the outer protective layer for driving the movement of the moving ring. The adjusting member includes: A fixing plate is fixedly connected to the outside of the outer protective layer; An adjusting screw is threadedly connected to the fixed plate, and the end of the adjusting screw is rotatably connected to the moving ring.

[0008] To achieve a detachable connection between the airbag and the moving ring, a Velcro closure is fixedly connected to the moving ring, and a Velcro closure is fixedly provided on the airbag. The airbag can be closed into a ring-shaped structure that matches the moving ring.

[0009] To facilitate the replacement of the desiccant, a replacement port is provided at one end of the closed ring near the outer side, and a sealing cap is detachably provided at the replacement port.

[0010] To achieve a removable waterproof layer, the waterproof layer includes two waterproof semi-rings. A sealing plate is fixedly connected to the end of each waterproof semi-ring. The two waterproof semi-rings are connected to each other outside the outer sheath by a fastener, which includes: The fixed half-ring is provided in multiple sets, with two fixed half-rings in each set. The two fixed half-rings are detachably connected by connecting bolts, and the fixed half-rings are tightly attached to the outer side of the waterproof layer. A limiting block is fixedly disposed on the outside of the waterproof layer, and a limiting groove matching the limiting block is provided on the fixing half ring.

[0011] The working principle and beneficial effects of this invention are as follows: 1. In this invention, by sequentially setting a detachable waterproof layer and multiple outer protective layers on the outside of the outer sheath, and setting a connecting sleeve between adjacent outer protective layers, the overall multi-layer protection of the cable is realized, and the modular installation and disassembly of the protective structure is realized. When a certain structure is damaged, it can be replaced individually without replacing the entire cable, which greatly reduces maintenance costs and difficulties.

[0012] 2. In this invention, at the connection between the connecting sleeve and the outer protective layer, a first seal is formed between the sealing ring and the inner wall of the connecting sleeve. At the same time, the elasticity of the sealing ring can achieve a certain degree of deflection between the connecting sleeve and the outer protective layer, adapting to the bending and laying of the cable. Furthermore, the movable moving ring and the sealed airbag provide adaptive sealing to the end of the connecting sleeve, adapting to the deflection between the connecting sleeve and the outer protective layer, effectively reducing the infiltration of moisture from the joint gap.

[0013] 3. In this invention, the gap between the outer protective layer and the waterproof layer is sealed by a closed ring. At the same time, the desiccant inside can actively absorb the trace amount of moisture that may enter the outer protective layer through tiny paths, reducing the further diffusion of moisture into the inner layer and providing a continuous and stable dry environment for the core structure of the cable. Attached Figure Description

[0014] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a side view of the planar structure of the present invention; Figure 3 This is a schematic diagram of the waterproof layer and fastener of the present invention; Figure 4 This is an exploded structural diagram of the waterproof layer and fastener of the present invention; Figure 5 This is a schematic diagram of the structure of the outer protective layer, connecting sleeve, sealing element and drying assembly of the present invention; Figure 6 This is an exploded structural diagram of the outer protective layer, connecting sleeve, sealing element, and drying assembly of the present invention; Figure 7 This is an exploded structural diagram of the outer protective layer, sealing element, and drying assembly of the present invention; Figure 8 This is a schematic diagram of the structure of the sealing element of the present invention; Figure 9 This is a schematic diagram of the drying component of the present invention.

[0016] In the picture: 1. Conductor; 2. Cross-linked polyethylene insulation layer; 3. Inner sheath; 4. Armor layer; 5. Outer sheath; 101. Waterproof semi-ring; 102. Sealing plate; 201. Fixed semi-ring; 202. Limiting block; 301. Protective half-ring; 302. Sealing ring; 401. Connect the half-ring; 501. Moving ring; 502. Sealing airbag; 503. Velcro fastener; 504. Velcro master fastener; 601. Fixing plate; 602. Adjusting screw; 701. Closing ring; 702. Sealing cap. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figures 1 to 2 As shown, this embodiment proposes a moisture-resistant and penetration-proof low-voltage cross-linked polyethylene insulated cable, including a conductor 1, a cross-linked polyethylene insulation layer 2, an inner sheath 3, an armor layer 4, and an outer sheath 5, and also includes a waterproof layer, an outer protective layer, a connecting sleeve, a sealant, and a drying component.

[0019] The cross-linked polyethylene insulation layer 2 is composed of modified cross-linked polyethylene material, comprising, by weight: 100 parts low-density polyethylene, 1.5-3.0 parts silane cross-linking agent, 0.05-0.2 parts catalyst, 0.3-0.8 parts antioxidant, 3-10 parts hydrophobic nanofiller, 0.5-2.0 parts hydrolysis stabilizer, and 0.2-0.6 parts ultraviolet absorber. The addition of hydrophobic nanofiller significantly reduces the water absorption rate of the insulation layer surface. Simultaneously, the hydrolysis stabilizer effectively inhibits the decomposition of ester groups or silicon-oxygen bonds in the presence of water, improving the insulation resistance retention rate in long-term humid environments. The synergistic effect of antioxidant and ultraviolet absorber improves the tensile strength and elongation at break retention rate of the material under acid, alkali, and salt spray environments, which is superior to ordinary cross-linked polyethylene. The hydrophobic filler also reduces the adhesion and penetration of corrosive liquids on the insulation layer surface. The inner sheath 3 is disposed outside the cross-linked polyethylene insulation layer 2. The inner sheath 3 and the cross-linked polyethylene insulation layer 2 are connected. A filler is provided between the insulation layers 2. The inner sheath 3 is extruded from polyvinyl chloride or low-smoke halogen-free flame-retardant polyolefin material. The main function of the inner sheath 3 is to provide a flat and uniform pad for the armor layer 4 and to buffer mechanical stress when the cable is bent. It also plays an auxiliary role in moisture protection and corrosion protection. The armor layer 4 is set outside the inner sheath 3 and adopts a double-layer galvanized steel strip wrapping or galvanized steel wire braiding structure. The steel strip wrapping method is suitable for occasions that are subjected to smaller mechanical external forces, while the steel wire braiding method is suitable for mines or direct burial environments that require higher tensile and compressive strength. The armor layer 4 can effectively resist external mechanical impact, squeezing and animal gnawing, and can also serve as a backup path for ground fault current. The outer sheath 5 is extruded outside the armor layer 4 and is made of weather-resistant polyvinyl chloride, polyethylene or low-smoke halogen-free flame-retardant polyolefin material. It has good corrosion resistance, UV resistance and aging resistance, and has a certain mechanical strength to protect the internal structure.

[0020] The waterproof layer is removably installed on the outside of the outer sheath 5, such as... Figures 1 to 4As shown, the waterproof layer includes two waterproof semi-rings 101. A sealing plate 102 is fixedly connected to the end of each waterproof semi-ring 101. The two waterproof semi-rings 101 are connected to each other outside the outer sheath 5 by fasteners. The fasteners include a fixing semi-ring 201 and a limiting block 202. Multiple sets of fixing semi-rings 201 are provided, with two fixing semi-rings 201 in each set. The two fixing semi-rings 201 are detachably connected by connecting bolts. The fixing semi-rings 201 are tightly fitted to the outer side of the waterproof layer. The limiting block 202 is fixedly installed outside the waterproof layer. The fixing semi-rings 201 have openings that match the limiting block 202. The limiting groove allows two waterproof semi-rings 101 to be spliced ​​into a complete ring and fitted onto the outside of the outer sheath 5, providing an additional waterproof barrier for the cable. The waterproof layer is made of waterproof rubber material, which has good elasticity and sealing performance. The sealing piece 102 between the waterproof semi-rings 101 can further fill the tiny gaps at the splice and enhance the waterproof effect. The two fixed semi-rings 201 are spliced ​​into a complete ring and fitted onto the outside of the waterproof layer by connecting bolts to lock it in place. The cooperation between the limiting block 202 and the limiting groove improves the splicing accuracy between the two waterproof semi-rings 101 and enhances the stability between the fixed semi-rings 201 and the waterproof layer.

[0021] Multiple outer protective layers are provided, and these outer protective layers are detachably installed outside the waterproof layer, such as... Figure 1 , Figures 5 to 7 As shown, the outer protective layer includes two protective semi-rings 301, which are detachably connected by bolts. A connecting sleeve is detachably installed between two adjacent outer protective layers. The connecting sleeve includes two connecting semi-rings 401, which are detachably connected by bolts. Multiple sealing rings 302 are fixedly fitted on the outer side of the end of the outer protective layer. The sealing rings 302 are in contact with the inner sidewall of the connecting sleeve. The outer protective layer provides additional waterproof and mechanical protection to the outside of the waterproof layer. The connecting sleeve blocks and seals the gap between two adjacent outer protective layers. At the same time, the sealing rings 302 seal the connection between the connecting sleeve and the outer protective layer to prevent external moisture from entering. The elasticity of the sealing rings 302 allows the connecting sleeve and the outer protective layer to bend to a certain extent, adapting to the cable laying requirements in complex environments, reducing gaps caused by bending at the connection, and improving the overall sealing performance.

[0022] The sealing element is located outside the outer protective layer and is used to provide a secondary seal for the gap between the connecting sleeve and the outer protective layer, such as... Figures 5 to 8As shown, the sealing element includes a movable ring 501 and a sealing airbag 502. The movable ring 501 is movably disposed outside the outer protective layer. There are two movable rings 501, each corresponding to a protective half-ring 301. To enable the movement of the movable ring 501, an adjusting component for driving the movement of the movable ring 501 is provided outside the outer protective layer. The adjusting component includes a fixed plate 601 and an adjusting screw 602. The fixed plate 601 is fixedly connected to the outside of the outer protective layer, and the adjusting screw 602 is threadedly connected to the fixed plate 601. The end of the adjusting screw 602 is rotatably connected to the movable ring 501. The sealing airbag 502 is detachably disposed on the movable ring 501. A Velcro fastener 503 is fixedly connected to the movable ring 501, and a Velcro fastener 504 is fixedly disposed on the sealing airbag 502. The sealing airbag 502 can be enclosed into a ring structure that matches the moving ring 501. The sealing airbag 502 and the end of the connecting sleeve contact to form a sealing structure. By rotating the adjusting screw 602, the moving ring 501 can be moved axially along the outer protective layer, causing the sealing airbag 502 to press against the end of the connecting sleeve, thereby providing a secondary seal for the gap between the connecting sleeve and the outer protective layer. At the same time, the sealing airbag 502 maintains an adaptive sealing state between itself, the connecting sleeve, and the outer protective layer, and can still maintain the sealing state of the connecting sleeve when the cable is bent. The sealing airbag 502 can be quickly installed and removed using Velcro. The sealing airbag 502 can be bent into a shape that matches the end of the connecting sleeve. The two ends of the sealing airbag 502 are tightly attached to each other or overlapped to avoid gaps and ensure the integrity of the seal.

[0023] The drying component is located on the inner side of the end of the outer protective layer to seal the gap between the outer protective layer and the waterproof layer, and to absorb moisture that enters the outer protective layer, such as... Figure 7 and Figure 9As shown, the drying assembly includes a sealing ring 701, which is fixedly disposed on the inner end of the outer protective layer. The sealing ring 701 has a hollow structure and is filled with desiccant. Multiple vent holes are provided at the inner end of the sealing ring 701, and a replacement port is provided at the outer end of the sealing ring 701. A sealing cap 702 is detachably disposed at the replacement port. A sealing gasket is fixedly connected to the inner side of the sealing ring 701, and the sealing gasket contacts the outer side of the waterproof layer. The sealing ring 701 and the sealing gasket ensure the airtightness between the outer protective layer and the waterproof layer, while the desiccant can... To absorb moisture entering the outer protective layer and connecting sleeve, chemical desiccants such as calcium sulfate and calcium chloride can be used, which dry by combining with water to form hydrates. Alternatively, physical desiccants such as silica gel and activated alumina can be used, which dry by physical adsorption. The sealing cover 702 is fastened to the replacement port of the sealing ring 701. The sealing cover 702 can be opened periodically to replace the desiccant that has become ineffective, ensuring the continuous moisture absorption capacity of the drying component. A humidity sensor and alarm can be installed inside the connecting sleeve to promptly remind staff to inspect and maintain the unit when excessive humidity is detected.

[0024] The working principle or usage process of this moisture-resistant and penetration-proof low-voltage cross-linked polyethylene insulated cable is as follows: During normal operation, the outermost multiple outer protective layers and connecting sleeves constitute the first line of defense. The gap between the outer protective layer and the connecting sleeve is filled and sealed by the sealing ring 302. At the same time, the elasticity of the sealing ring 302 allows the connection between the outer protective layer and the connecting sleeve to deflect to a certain extent. Rotating the adjusting screw 602 adjusts the position of the moving ring 501, so that the sealing airbag 502 adaptively presses against the end of the connecting sleeve to seal the gap between the connecting sleeve and the outer protective layer. The sealing airbag 502 can be replaced by Velcro. After the outer protective layer or connecting sleeve is damaged, the specific outer protective layer or connecting sleeve can be disassembled and replaced. The waterproof layer is fixed to the outside of the outer sheath 5 by fixing the half ring 201 as a second line of defense. The contact position between the waterproof half rings 101 is sealed and protected by the sealing piece 102. The waterproof layer prevents trace amounts of water that may penetrate the outer protective layer from contacting the outer sheath 5. At the same time, the damaged waterproof layer can be replaced after being corroded or damaged. The sealing ring 701 seals the space between the outer protective layer and the waterproof layer. At the same time, the desiccant inside the sealing ring 701 acts as a third active line of defense, continuously absorbing any moisture that may enter. Through the synergistic effect of these three lines of defense, the cable can maintain its internal dryness for a long time, even in humid environments such as mines and underground pipe corridors.

[0025] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A moisture resistant, impermeable, low voltage crosslinked polyethylene insulated cable comprising a conductor (1), a crosslinked polyethylene insulation layer (2), an inner semiconductive layer (3), an armour layer (4) and an outer semiconductive layer (5), characterised in that, Also includes: A waterproof layer, which is detachably disposed on the outside of the outer sheath (5); An outer protective layer, wherein multiple outer protective layers are provided, and the outer protective layers are detachably disposed outside the waterproof layer; A connecting sleeve is detachably disposed between two adjacent outer protective layers. Multiple sealing rings (302) are fixedly fitted on the outer side of the end of the outer protective layer. The sealing rings (302) are in contact with the inner sidewall of the connecting sleeve. A sealing element, which is disposed outside the outer protective layer, is used to perform secondary sealing treatment on the gap between the connecting sleeve and the outer protective layer; A drying component is disposed on the inner side of the end of the outer protective layer to seal the gap between the outer protective layer and the waterproof layer and to absorb moisture entering the outer protective layer.

2. A damp-proof, moisture-resistant, low-voltage crosslinked polyethylene insulated cable according to claim 1, characterized in that, The sealing element includes: A movable ring (501) is movably disposed outside the outer protective layer; A sealing airbag (502) is detachably mounted on the moving ring (501), and the ends of the sealing airbag (502) and the connecting sleeve are in contact to form a sealing structure.

3. A moisture resistant, impermeable, low voltage crosslinked polyethylene insulated cable according to claim 1, characterized in that, The drying assembly includes: A closed ring (701) is fixedly disposed at the inner end of the outer protective layer. The closed ring (701) has a hollow structure and is filled with a desiccant. The closed ring (701) has multiple ventilation holes at one end facing inward.

4. A damp-proof, moisture resistant, low pressure cross-linked polyethylene insulated cable according to claim 2, characterized in that, An adjustment element for driving the moving ring (501) to move is provided on the outside of the outer protective layer.

5. A damp-proof, moisture-resistant, low-pressure cross-linked polyethylene insulated cable according to claim 4, characterized in that, The adjusting element includes: A fixing plate (601) is fixedly connected to the outside of the outer protective layer; An adjusting screw (602) is threadedly connected to the fixed plate (601), and the end of the adjusting screw (602) is rotatably connected to the moving ring (501).

6. A damp-proof, moisture-resistant, low-pressure cross-linked polyethylene insulated cable according to claim 5, characterized in that, The movable ring (501) is fixedly connected with a Velcro tab (503), and the closed airbag (502) is fixedly provided with a Velcro tab (504). The closed airbag (502) can be enclosed into a ring structure that matches the movable ring (501).

7. A damp-proof, moisture resistant, low pressure cross-linked polyethylene insulated cable according to claim 3, wherein, The closed ring (701) has a replacement port at one end near the outer side, and a sealing cap (702) is detachably provided at the replacement port.

8. A moisture resistant, impermeable, low voltage crosslinked polyethylene insulated cable according to claim 1, characterized in that, The waterproof layer includes a waterproof semi-ring (101), and two waterproof semi-rings (101) are provided. A sealing plate (102) is fixedly connected to the end of the waterproof semi-ring (101). The two waterproof semi-rings (101) are set outside the outer sheath (5) by a fastener.

9. A damp-proof, moisture-resistant, low-pressure cross-linked polyethylene insulated cable according to claim 8, characterized in that, The fastener includes: Fixed half ring (201), the fixed half ring (201) is provided in multiple sets, each set of the fixed half ring (201) has two fixed half rings (201), the two fixed half rings (201) are detachably connected by connecting bolts, and the fixed half ring (201) is tightly attached to the outside of the waterproof layer; The limiting block (202) is fixedly disposed on the outside of the waterproof layer, and the fixing half ring (201) is provided with a limiting groove that matches the limiting block (202).

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