Crosslinked polyethylene insulated cable and preparation method thereof

Abstract

The invention relates to the field of cable processing, in particular to a crosslinked polyethylene insulated cable and a preparation method thereof. The plastic extruding machine is provided with two plastic extruding outlets, the inner side of each cross-linking pipe is fixedly connected with a semi-spiral plate, and the screw pitch of the semi-spiral plates is gradually reduced from left to right. A cable core in the cable is formed by twisting a plurality of copper wires, the outer layer of the cable core is a crosslinked polyethylene inner sheath, and the outermost layer is a polyethylene outer sheath. The method comprises the following steps: S1, twisting a plurality of copper wires, enabling the copper wires to penetrate into an extrusion molding outlet of an extrusion molding machine, and enabling the copper wires to penetrate out of another extrusion molding outlet of the extrusion molding machine; s2, an electric push rod is driven to contract, meanwhile, a threaded rod is rotated, then two driving rollers on a support are driven to rotate, after a period of time, the electric push rod is extended, rotation of the driving rollers is stopped, and then the threaded rod is driven to rotate reversely; s3, a hydraulic rod is driven to extend; s4, a hydraulic rod is driven to contract; and S5, repeating the steps S2 to S4. Cracking of the cable due to different tensile strengths of the inner side and the outer side of the cable skin during processing can be avoided.

Description

Technical Field

[0001] The present invention relates to the field of cable processing, and more specifically to a cross-linked polyethylene insulated cable and a preparation method thereof. Background Art

[0002] A cross-linked polyethylene cable is a high-performance cable in which polyethylene molecular chains are cross-linked by chemical or physical methods to form a three-dimensional network structure. Its insulating layer or sheath material has excellent heat resistance, mechanical strength and electrical properties, and is widely used in fields such as power transmission, rail transit, and new energy. However, in traditional cross-linking, due to the relatively thick cable sheath, the cross-linking degree gradient of the cable insulating layer is large, with over-cross-linking on the surface and under-cross-linking in the core. This will further cause the tensile strength of the inner and outer layers of the manufactured cable to be less than that of the inner layer. When bending, the outer layer is subjected to greater tensile force, resulting in it being more likely to crack. Summary of the Invention

[0003] The present invention provides a cross-linked polyethylene insulated cable and a preparation method thereof, aiming to avoid the cable from cracking due to different tensile strengths on the inner and outer sides of the cable sheath during processing.

[0004] The above object is achieved by the following technical solutions:

[0005] A cross-linked polyethylene insulated cable processing device, characterized in that: it includes a bottom plate, an extruder is provided on the bottom plate, two extrusion outlets are provided on the extruder, two cross-linking tubes are slidably connected to the bottom plate, an electric push rod is provided between each cross-linking tube and the bottom plate, a semi-helical plate is fixedly connected to the inner side of each cross-linking tube, and the pitch of the semi-helical plate gradually decreases from left to right. Two connecting pipes are fixedly connected to one side of the cross-linking tube, a telescopic tube is fixedly connected to each connecting pipe, and the other ends of the two telescopic tubes are fixedly connected to a side plate.

[0006] The cable core inside the cable is formed by stranding multiple copper wires, the inner skin of the cross-linked polyethylene layer is on the outer layer of the cable core, and the outermost layer is a polyethylene outer skin.

[0007] A preparation method used for a cross-linked polyethylene insulated cable processing device includes the following steps;

[0008] S1: Strand multiple copper wires and then pass them through one extrusion outlet on the extruder, and then sequentially pass through two cross-linking tubes, two clamping plates, two fixing plates, an arc-shaped push rod and a bracket, and then pass out through the other extrusion outlet of the extruder;

[0009] S2: Drive the electric push rod to contract, and at the same time rotate the threaded rod, then drive the two driving rollers on the bracket to rotate. After a period of time, extend the electric push rod, stop the driving rollers from rotating, and then drive the threaded rod to rotate in the reverse direction;

[0010] S3: Fix the cable at one end of the other extrusion outlet, and at the same time drive the hydraulic rod to extend;

[0011] S4: Pull the cable at one end of the other extrusion outlet while driving the hydraulic rod to contract;

[0012] S5: Repeat S2 to S4. Description of the Drawings

[0013] Figure 1 It is a flowchart of a method for a cross-linked polyethylene insulated cable processing device;

[0014] Figure 2 It is a schematic diagram of the overall structure of a cross-linked polyethylene insulated cable processing device;

[0015] Figure 3 It is a schematic diagram of the structure of the extruder part;

[0016] Figure 4 It is a schematic diagram of the structure of the cross-linking tube part;

[0017] Figure 5 It is a schematic diagram of the structure of the semi-helical plate part;

[0018] Figure 6 It is a schematic diagram of the structure of the telescopic tube part;

[0019] Figure 7 It is a schematic diagram of the structure of the clamping plate and fixed plate parts;

[0020] Figure 8 It is a schematic diagram of the structure of the convex strip part;

[0021] Figure 9 It is a schematic diagram of the structure of the fixed plate part;

[0022] Figure 10 It is a schematic diagram of the structure of the flower tooth part;

[0023] Figure 11 It is a schematic diagram of the structure of the rack part;

[0024] Figure 12 It is a schematic diagram of the structure of the rotating shaft part;

[0025] Figure 13 It is a schematic diagram of the structure of the arc-shaped push rod part;

[0026] Figure 14 It is a schematic diagram of the structure of the bracket part.

[0027] In the figure: extrusion machine 11; bottom plate 12; side plate 201; cross-linking pipe 202; telescopic pipe 203; sliding rod 204; rotating plate 205; push rod 206; semi-helical plate 207; clamping plate 13; convex strip 301; tension spring 302; top block 303; flower teeth 304; connecting rod 305; fixing plate 14; fan 401; belt pulley 402; rotating shaft 403; belt 404; first bevel gear 405; second bevel gear 406; first gear 407; tooth profile 408; arc-shaped push rod 15; fixing rod 501; rack 502; second gear 503; bracket 16; driving roller 601; friction belt 602; connecting rod 603; slider 604; threaded rod 605. Detailed implementation manner

[0028] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and 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 therefore should not be construed as a limitation of the present invention.

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] As Figures 2 to 5 , to solve the problem of insufficient cross-linking.

[0031] An extrusion machine 11 is provided on the bottom plate 12. The extrusion machine 11 is provided with two extrusion outlets. Two cross-linking pipes 202 are slidably connected to the bottom plate 12. An electric push rod is provided between each cross-linking pipe 202 and the bottom plate 12. A semi-helical plate 207 is fixedly connected to the inner side of each cross-linking pipe 202. The pitch of the semi-helical plate 207 gradually decreases from left to right. Two connecting pipes are fixedly connected to one side of the cross-linking pipe 202. A telescopic pipe 203 is fixedly connected to each connecting pipe. The other ends of the two telescopic pipes 203 are fixedly connected to the side plate 201.

[0032] When this device is in operation, multiple copper wires are first stranded to form the cable core. Then, the cable core is passed through the extruder 11 and exits from one of the extrusion outlets. Two electric push rods 202 are connected in parallel in the same drive circuit, enabling them to simultaneously drive the two cross-linking tubes 202 to move towards the center, thereby wrapping the cable inner skin formed by extrusion. At this time, the two semi-helical plates 207 together form a spiral flow guide plate. On one side of the side plate 201 away from the extruder 11, a silane jet port is provided and connected to the telescopic tube 203. On the other side, a waste treatment device is provided and connected to another telescopic tube 203. Thus, when the two cross-linking tubes 202 are closed, silane enters from the telescopic tube 203 at the end away from the extruder and is guided by the spiral flow guide plate. The spiral flow guide plate can increase the travel of silane within the cross-linking tube 202, ensuring that the cross-linking reaction proceeds fully. Initially, the pitch of the spiral flow guide plate gradually decreases, increasing the flow velocity of the air flow. The inner skin formed by extrusion will have a gradually decreasing temperature from left to right due to different contact times with air. By changing the internal air flow velocity, the contact time between the high-temperature silane and the inner skin is different, thereby balancing the overall temperature between the two cross-linking tubes 202 and enhancing the cross-linking effect on the inner skin. After cross-linking, the cable passes through another extrusion outlet of the extruder 11 and is extruded again, and then cooled using the existing water-cooling method. Finally, the cable finished product is wound and reserved using the existing equipment.

[0033] For the cable formed by processing with this device, the inner part is a stranded copper wire as the cable core, and the inner layer is a cross-linked polyethylene layer as the inner skin, which can ensure that no deformation occurs when the inner cable core works and generates heat. At the same time, the outer traditional polyethylene outer skin compensates for the problem of low tensile strength of traditional cross-linked polyethylene cables, ensuring that the cable can be applied to smaller bending angles without damage. At the same time, the entire cable skin is divided into two layers, which can prevent the cable skin from being too thick, resulting in insufficient cross-linking and causing a gradient distribution phenomenon of the gel rate of the insulating layer being high on the outside and low on the inside, affecting its insulation performance and high-temperature resistance, thus posing a danger.

[0034] Such as Figure 6 , to solve the problem of the service life of the pipeline when the cross-linking tube moves.

[0035] At one end of the side plate 201 where each telescopic tube 203 is located, a sliding rod 204 is fixedly connected. The other end of each telescopic tube 203 is slidably connected to the sliding rod 204. A push rod 206 is fixedly connected to another cross-linking tube 202. At one end of the side plate 201 where each telescopic tube 203 is located, a rotating plate 205 is rotatably connected, and a coil spring is provided between the rotating plate 205 and the telescopic tube 203.

[0036] During cable processing, movement is required. Since the cross-linking process needs to be carried out when the polyethylene has not yet solidified, the two cross-linking tubes 202 can move, which can avoid the collision and friction between the internal semi-helical plate 207 and the cable, thus preventing it from deforming. During the movement of the cross-linking tube 202, the pipeline of the silane gas will be deformed. Therefore, a telescopic rod 203 is set to increase its service life. When the cross-linking tube 202 moves, it drives the mobile end of the telescopic tube 203 to slide along the slide bar 204, so that the whole telescopic tube 203 expands and contracts, evenly distributing the generated stress, thus preventing it from skewing and causing damage to one side of the telescopic tube 203 due to long-term deformation. When the two cross-linking tubes 202 approach, the push rod 206 is driven to move towards the side plate 201, thereby pushing the rotating plate 205 to rotate. Initially, the rotating plate 205 is driven by a coil spring to close the telescopic tube 203. Thus, when the two cross-linking tubes 202 are closed, the telescopic tube 203 can form a passage, thereby avoiding malfunctions of the silane ejection control equipment and preventing leakage from affecting the processing safety.

[0037] As Figures 7 to 11 , to solve the problem of connection between the inner layer and the outer layer of the cable.

[0038] Two clamping plates 13 are slidably connected to the bottom plate 12. Each clamping plate 13 is provided with a plurality of convex strips 301. A tension spring 302 is fixedly connected between the two clamping plates 13. A top block 303 is fixedly connected to each clamping plate 13. A flower gear 304 is rotatably connected to the bottom plate 12, and the flower gear 304 is in contact with the top block 303.

[0039] The cable sheath processed by this equipment is divided into an inner layer and an outer layer. To ensure the tight fit of the two sheath layers, two clamping plates 13 are provided. The tension spring 302 between the two clamping plates 13 can pull them to be in a closed state. After the cable cross-linking is completed, the extrusion work continues. The cable is pulled. At this time, the flower gear 304 is driven to rotate. When the protruding part contacts the top block 303, the two top blocks 303 move to both sides, thereby driving the two clamping plates 13 to move away. Then, as the flower gear 304 rotates, when the top block 303 rotates to contact the concave part, the tension spring 302 pulls the two clamping plates 13 to quickly contract, thereby driving the convex strips 301 on them to squeeze the inner skin of the cable, so as to generate small grooves on its surface when the cross-linked sheath has not yet been shaped, which is convenient for increasing the contact area between the inner skin and the outer skin and enhancing the adhesion effect between the two during subsequent extrusion processing.

[0040] As Figures 7 to 12 , to solve the problem of cooling the inner skin.

[0041] A fixing plate 14 is fixedly connected to each splint 13 through a connecting rod 305. A plurality of fans 401 are rotatably connected to each fixing plate 14. A pulley 402 is fixedly connected to the rotating shaft of each fan 401. The pulleys 402 on the same side are connected by a belt 404.

[0042] After cross-linking is completed, since it needs to be pulled to continue the cross-linking work after extrusion, when the two splints 13 move, the two fixing plates 14 are driven to move synchronously through the connecting rod 305, and then the fans 401 thereon are driven to move reciprocally. One fan 401 on one side is controlled to rotate, and then the plurality of fans are driven to rotate synchronously through the pulley 402, thereby initially cooling the inner skin, avoiding extrusion between the pulled part and the inner skin of the cable during the cable pulling process, resulting in deformation, and thus uneven distribution of the cross-linked layer.

[0043] Such as Figures 9 to 13 to solve the problem that the serrated teeth 304 rotate as the cable moves.

[0044] A hydraulic rod is fixed to the bottom plate 12 by bolts. A fixed rod 501 is fixedly connected to the moving end of the hydraulic rod. An arc-shaped push rod 15 is fixedly connected to the fixed rod 501. A rack 502 is fixedly connected to the fixed rod 501. A second gear 503 is fixedly connected to the rotating shaft of the serrated teeth 304. The second gear 503 meshes with the rack 502.

[0045] Initially, the hydraulic rod is in a contracted state. After cross-linking is completed, the two electric push rods are contracted, and then the hydraulic rod is driven to extend. Since one end of the finished cable is fixed to the winding device, at this time, the extension of the hydraulic rod drives the arc-shaped push rod 15 to move. As shown in Figure 12 , the right cable part is fixed and does not move. At this time, the left part continues the extrusion process. When the arc-shaped push rod 15 moves, it drives the fixed rod 501 to move, and then drives the rack 502 to slide relative to the bottom plate 12, thereby meshing and driving the second gear 503 to rotate, and then driving the serrated teeth 304 to rotate, so as to realize the extrusion work on the cable during the first extrusion process. At the same time, when the cable is pulled, due to the friction between the cable and the arc-shaped push rod 15, the fan 401 rotates to cool the cable surface to avoid deformation.

[0046] Preferably, to further avoid deformation caused by relative movement between the cable and the arc-shaped push rod 15, the arc-shaped push rod 15 is set as a turntable rotatably connected to the fixed rod 501. Then, when the cable is pulled, the turntable rotates, changing the sliding friction with the cable into rolling friction to avoid deformation.

[0047] Such as Figures 8 to 12 to solve the problem that the fan 401 rotates when the fixing plate 14 moves.

[0048] A first bevel gear 405 is fixedly connected to each of the fans 401 on each fixing plate 14. A rotating shaft 403 is rotatably connected to each fixing plate 14. A second bevel gear 406 is fixedly connected to each rotating shaft 403. Each first bevel gear 405 meshes with the corresponding second bevel gear 406. A first gear 407 is fixedly connected to each rotating shaft 403. Two tooth profiles 408 are provided on the bottom plate 12. Each first gear 407 meshes with the corresponding tooth profile 408.

[0049] When the fixing plate 14 moves, it drives the rotating shaft 403 to move, and then drives the first gear 407 to move. Then, the first gear 407 is meshed and driven to rotate by the tooth profile 408, which drives the rotating shaft 403 to rotate, and then drives the second bevel gear 406 to rotate, meshing and driving the first bevel gear 405 to rotate, and then driving the fan 401 to rotate. The multiple fans 401 are driven by the belt pulley 402 and the belt 404 to rotate synchronously, increasing the air flow rate around the cable for cooling.

[0050] Such as Figure 13 And Figure 14 , to further increase the connection effect between the cable inner skin and the cable outer skin.

[0051] A bracket 16 is provided on the bottom plate 12. Two driving rollers 601 are rotatably connected to the bracket 16. Two mutually hinged connecting rods 603 are rotatably connected to both ends of each driving roller 601. The other ends of the mutually hinged connecting rods 603 are rotatably connected to a driving roller 601. A friction belt 602 is provided between the corresponding two driving rollers 601.

[0052] By moving the two driving rollers 601 below and the two mutually hinged connecting rods 603, the friction belts 602 on both sides clamp the cable. A motor is provided on the bracket 16. The output shaft of the motor drives the two driving rollers 601 located above through a transmission mechanism. When the driving rollers 601 rotate, they drive the friction belt 602 to rotate, thereby frictionally cleaning the surface of the cable, preventing the dust in the air driven by the rotation of the fan 401 from adhering to the surface of the cable inner skin, which may affect the bonding effect between the outer skin and the inner skin during the second extrusion process.

[0053] Such as Figure 14 , to solve the problem of the movement of the two driving rollers 601 located below.

[0054] A slider 604 is rotatably connected to both ends of the two driving rollers 601 located below. Each slider 604 is slidably connected to the bottom plate 12. A threaded rod 605 is rotatably connected to the bracket 16. The threaded rod 605 drives the two sliders 604 on the same side through threading.

[0055] Drive the threaded rod 605 to rotate. The threaded rod 605 is provided with threads with opposite helix directions at both ends. The two sliders 404 are respectively engaged with the two sections of threads. Then, when cleaning work is carried out, the two sliders 604 are driven to approach each other, thereby tightening the friction belt 602 to ensure the cleaning effect on the cable. After the cleaning is completed, rotate the threaded rod 605 in the reverse direction to reduce the resistance to the cable, and drive the cable winding mechanism to pull the cable for the second extrusion work. At the same time, after cooling, the finished cable is formed and wound for standby.

[0056] For the cable processed by this equipment, the cable core inside the cable is composed of multiple copper wires stranded together. The outer layer of the cable core is the inner skin of the cross-linked polyethylene layer to ensure the high-temperature resistance performance when the inner cable core generates heat. The outermost layer is the polyethylene outer skin to ensure the overall ductility of the cable skin, facilitating the laying work under a smaller bending radius.

[0057] Such as Figure 1 , a processing method used for a cross-linked polyethylene insulated cable processing equipment, including the following steps;

[0058] S1: Strands multiple copper wires and thread them through an extrusion outlet on the extruder 11, then sequentially pass through two cross-linking tubes 202, two clamping plates 13, two fixing plates 14, the arc-shaped push rod 15 and the bracket 16, and then pass out through another extrusion outlet of the extruder 11;

[0059] S2: Drive the electric push rod to contract to carry out the cross-linking work on the inner layer of the cable skin. At the same time, rotate the threaded rod 605, and then drive the two driving rollers 601 on the bracket 16 to rotate to clean the cable skin. After a period of time, stop the rotation of the driving rollers 601, and then drive the threaded rod 605 to rotate in the reverse direction;

[0060] S3: Fix the cable at one end of another extrusion outlet, and at the same time drive the hydraulic rod to extend to carry out the first extrusion work;

[0061] S4: Pull the cable at one end of another extrusion outlet, and at the same time drive the hydraulic rod to contract to carry out the second extrusion work;

[0062] S5: Repeat S2 to S4.

Claims

1. A cross-linked polyethylene insulated cable processing device, characterized in that: It includes a bottom plate, an extruder is arranged on the bottom plate, two extrusion outlets are arranged on the extruder, two cross-linked tubes are slidably connected to the bottom plate, an electric push rod is arranged between each cross-linked tube and the bottom plate, a semi-spiral plate is fixedly connected to the inner side of each cross-linked tube, the pitch of the semi-spiral plate gradually decreases from left to right, two connecting tubes are fixedly connected to the cross-linked tube on one side, a telescopic tube is fixedly connected to each connecting tube, and the other ends of the two telescopic tubes are fixedly connected to side plates.

2. The cross-linked polyethylene insulated cable processing equipment according to claim 1, characterized in that: One end of each telescopic tube located on the side plate is fixedly connected to a sliding rod, and the other end of each telescopic tube is slidably connected to the sliding rod. A push rod is fixedly connected to the other cross-linking tube. One end of each telescopic tube located on the side plate is rotatably connected to a rotating plate, and a coil spring is arranged between the rotating plate and the telescopic tube.

3. The cross-linked polyethylene insulated cable processing equipment according to claim 2, characterized in that: Two clamping plates are slidably connected to the bottom plate, a plurality of convex strips are arranged in each clamping plate, a tension spring is fixed between the two clamping plates, a top block is fixed on each clamping plate, and flower teeth are rotatably connected to the bottom plate, and the flower teeth are in contact with the top block.

4. The cross-linked polyethylene insulated cable processing equipment according to claim 3, characterized in that: A fixed plate is fixedly connected to each clamping plate through a connecting rod, and a plurality of fans are rotatably connected to each fixed plate. A pulley is fixedly connected to the rotating shaft of each fan, and a plurality of pulleys on the same side are connected by belts.

5. The cross-linked polyethylene insulated cable processing equipment according to claim 4, characterized in that: A hydraulic rod is fixed on the bottom plate by bolts, a fixed rod is fixedly connected to the movable end of the hydraulic rod, an arc push rod is fixedly connected to the fixed rod, a rack is fixedly connected to the fixed rod, a second gear is fixedly connected to the rotating shaft of the flower teeth, and the second gear is meshed with the rack.

6. The cross-linked polyethylene insulated cable processing equipment according to claim 4, characterized in that: A first bevel gear is fixedly connected to a fan on each fixed plate, a rotating shaft is rotatably connected to each fixed plate, a second bevel gear is fixedly connected to each rotating shaft, each first bevel gear is meshed with the corresponding second bevel gear, a first gear is fixedly connected to each rotating shaft, two teeth are provided on the bottom plate, and each first gear is meshed with the corresponding tooth.

7. The cross-linked polyethylene insulated cable processing equipment according to claim 6, characterized in that: A bracket is provided on the bottom plate, and two driving rollers are rotatably connected to the bracket. Both ends of each driving roller are rotatably connected to two mutually hinged connecting rods, and the other end of the mutually hinged connecting rod is rotatably connected to a driving roller, and a friction belt is provided between the two corresponding driving rollers.

8. The cross-linked polyethylene insulated cable processing equipment according to claim 7, characterized in that: Both ends of the two driving rollers located below are rotatably connected with a slider, each slider is slidably connected to the bottom plate, and a threaded rod is rotatably connected to the bracket, and the threaded rod threadably drives the two sliders on the same side.

9. The cross-linked polyethylene insulated cable prepared by the cross-linked polyethylene insulated cable processing equipment according to claim 8, wherein: The internal core of the cable is made of multiple copper wires twisted together, the outer layer of the cable core is a cross-linked polyethylene inner layer, and the outermost layer is a polyethylene outer layer.

10. The preparation method used for the cross-linked polyethylene insulated cable processing equipment according to claim 8, characterized in that: The method comprises the following steps: S1: twist multiple copper wires and pass them through an extrusion outlet on the extruder, then pass through two cross-linking tubes, two clamping plates, two fixing plates, arc-shaped push rods and brackets in sequence, and then pass through another extrusion outlet of the extruder; S2: Drive the electric push rod to retract and rotate the threaded rod at the same time, then drive the two driving rollers on the bracket to rotate, after a period of time, extend the electric push rod, stop the driving roller from rotating, and then drive the threaded rod to rotate in the opposite direction; S3: fix the cable at one end of the other extrusion outlet and drive the hydraulic rod to extend at the same time; S4: Pull the cable at one end of the other extrusion outlet and drive the hydraulic rod to retract at the same time; S5: Repeat S2 to S4.

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