Nylon sheath power cable manufacturing device and manufacturing method thereof

Abstract

The invention discloses a nylon sheath power cable manufacturing device and a manufacturing method thereof, and belongs to the technical field of cable extrusion molding, the nylon sheath power cable manufacturing device comprises a co-extrusion machine head, the co-extrusion machine head comprises a first feed inlet, a first extrusion molding runner is arranged on the co-extrusion machine head, a first closing opening is formed in the first extrusion molding runner, and a second feed inlet is formed in the second extrusion molding runner; a first extrusion molding cavity and a second extrusion molding cavity are formed in the two sides of the first closing-in opening, the first extrusion molding cavity is gradually reduced from the first feeding opening to the first closing-in opening, and a flaring shape is formed in the connecting position of the first closing-in opening and the second extrusion molding cavity. The extrusion material in the first extrusion runner can release internal stress in the extrusion material, so that the adhesion effect and the mechanical property of the extrusion material on the hot melt adhesive layer outside the cable core are stronger; according to the scheme, the mechanical protection function of the cable sheath can be improved, and the sheath reinforcing layer is prevented from corrugation, deformation and failure.

Description

Technical Field

[0001] The invention relates to a structure of a cable sheath manufacturing device, and more specifically, to a nylon sheath power cable manufacturing device and a manufacturing method thereof. Background Art

[0002] During the installation and laying of cables, large-sized power cables are heavy, require long cable traction distances, and have a complex external environment. They are often damaged by sharp objects such as iron frames and stones. Therefore, nylon sheaths are more suitable for the reinforcement layer of large-sized cable sheaths. While improving the mechanical protection function of the cable, the wear-resistant and self-lubricating properties of the nylon sheath reinforcement layer can reduce the traction force in laying scenarios such as cable threading and bending, thereby protecting the cable. However, considering the dual factors of mechanical protection and cost control of the cable sheath, nylon is used as the reinforcement layer structure of the large-sized cable sheath. Due to its thin thickness and large outer diameter of the cable (often exceeding 100mm in diameter), cable bending often causes the nylon sheath reinforcement layer to peel off from the inner sheath layer, and the nylon sheath reinforcement layer to wrinkle and deform, losing its mechanical protection function.

[0003] For example: Chinese patent announcement number CN217719155U, announcement date November 1, 2020, the name of the utility model is a horizontal three-layer co-extrusion extrusion unit. The application discloses a cable insulation material extrusion device, including adding an external shielding extruder on the basis of a double-layer co-extrusion extruder, and the extrusion ports of the double-layer co-extrusion extruder are connected to a three-layer co-extrusion head. This solution solves the problem that the processing temperature of modified polypropylene insulation materials, polypropylene conductor shielding and insulation shielding materials used in environmentally friendly polypropylene insulated power cables with rated voltages of 26 / 35kV and below is high, and the existing CCV three-layer co-extrusion unit cannot meet production needs. However, in this scheme, the internal stress of the extruded insulating material in the co-extrusion head is concentrated, which can easily cause the sheath layer to peel off or crack after the cable is bent, and lose its mechanical protection function. Summary of the invention

[0004] The present invention overcomes the problem that the cable sheath is prone to bending, peeling or cracking during use, and the nylon sheath reinforcement layer is wrinkled and deformed and loses its mechanical protection function. A nylon sheath power cable manufacturing device and a manufacturing method thereof are provided. This solution can improve the mechanical protection function of the cable sheath and avoid the wrinkle, deformation and failure of the sheath reinforcement layer.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: a nylon sheathed power cable manufacturing device, comprising a co-extrusion head, the co-extrusion head comprising a first feed port, a first extrusion flow channel is arranged on the co-extrusion head, a first closing opening is arranged in the first extrusion flow channel, a first extrusion cavity and a second extrusion cavity are formed on both sides of the first closing opening, the first extrusion cavity gradually decreases from the first feed port to the first closing position, and a flared shape is formed at the connection between the first closing opening and the second extrusion cavity. In the present scheme, the first extrusion flow channel is used to cover the hot melt adhesive middle layer on the outer sheath outside the cable core. The first closing in the first extrusion flow channel enables the first extrusion flow channel to form a first extrusion cavity and a second extrusion cavity on both sides of the first closing. The first extrusion cavity is close to the first feed port, and the second extrusion cavity is close to the co-extrusion head discharge port. The extruded plastic enters the first extrusion cavity after entering from the first feed port, and as the aperture of the first extrusion cavity gradually decreases, the pressure between the extruded plastics gradually increases, so that the extruded plastic forms a denser structure. After the extruded plastic passes through the first closing, it enters the second extrusion cavity. The aperture of the second extrusion cavity suddenly increases. At this time, the extruded plastic loses the pressure effect, thereby producing a certain expansion, releasing its internal stress, so that the adhesion effect and mechanical properties of the extruded plastic on the hot melt adhesive middle layer outside the cable core are stronger; at the same time, the aperture of the second extrusion cavity at the first closing suddenly increases, which can also prevent the extruded plastic from being broken during long-distance movement, and avoid the intermittent and uneven structure of the hot melt adhesive middle layer outside the cable core.

[0006] Preferably, the co-extrusion head also includes a second extrusion channel arranged on the outer periphery of the first extrusion channel and a second feed port arranged on the outer shell of the co-extrusion head, and the second feed port is inclined relative to the second extrusion channel, so that the feeding direction of the second feed port is opposite to the flow direction of the second extrusion channel. The second extrusion flow channel is used to form a nylon reinforcement layer outside the hot melt adhesive middle layer, so that the outermost nylon reinforcement layer can be tightly combined with the first cable outer sheath through the hot melt adhesive middle layer to form a stable cable sheath structure. The second extrusion flow channel feeds through the second feed port, and the second feed port is inclined relative to the second extrusion flow channel, so that the extruded plastic at the second feed port can produce a hedging effect when entering the second extrusion flow channel. On the one hand, it makes the extruded plastic produce a reversal. During the reversal process, the extruded plastic needs to move in the opposite direction, so that the extruded plastic is more uniform. On the other hand, it can make the extruded plastic form part of the extruded plastic on the side away from the co-extrusion head outlet, and increase the amount of extruded plastic on the half side of the co-extrusion head away from the second feed port, so that the extruded plastic can form a ring-shaped extruded plastic with more uniform and stable density in the second extrusion flow channel. At the same time, it can also avoid that most of the extruded plastic directly enters the second extrusion flow channel near the second feed port and moves directly toward the co-extrusion head outlet, so as to avoid uneven distribution of the nylon reinforcement layer outside the cable hot melt adhesive middle layer.

[0007] Preferably, the first extrusion flow channel and the second extrusion flow channel are connected to the discharge port of the co-extrusion head together, and a plurality of adjustment blocks are provided on the circumference of the co-extrusion head shell, and the adjustment blocks are provided at the second extrusion flow channel and before the first extrusion flow channel and the second extrusion flow channel are connected. The extruded plastics in the first extrusion flow channel and the second extrusion flow channel are finally merged together and extruded from the discharge port, a hot melt adhesive middle layer is extruded in the first extrusion flow channel, and a nylon reinforcement layer is extruded in the second extrusion flow channel, and the hot melt adhesive middle layer is located outside the outer sheath of the cable. An adjustment block is provided in the second extrusion flow channel, and the adjustment block is used to adjust the local aperture size in the second extrusion flow channel, so that when the extruded plastic in the second extrusion flow channel passes through the adjustment block, it is first pressurized and then pressure released, thereby reducing the stress inside the extruded plastic, so that the mechanical properties of the extruded plastic after molding are higher and the performance is more stable.

[0008] Preferably, the adjustment block can slide radially along the co-extrusion die head, and the side of the adjustment block close to the second extrusion flow channel is a cambered convex structure. The adjustment block itself can be adjusted in the radial direction of the co-extrusion die head, thereby changing the local aperture size of the second extrusion flow channel. On the one hand, it can prevent the extruded plastic from being broken and causing uneven distribution of the extruded plastic. On the other hand, by adjusting different apertures, it can also be applied to extruded plastics with different properties, and has a wider applicability.

[0009] Preferably, a core is provided at the discharge port of the co-extrusion head, and the half side of the core close to the first feed port or the second feed port is a conical surface, and the half side of the core away from the first feed port or the second feed port forms a pressure-holding flow channel together with the first extrusion flow channel and the second extrusion flow channel, and the portion of the core located after the pressure-holding flow channel is a conical surface. The extruded plastic is denser at the position of the core close to the feed port, and the density is more uniform and stable; while the extruded plastic at the position of the core away from the feed port is less dense than the extruded plastic closer to the feed port, and the consistency of density is also relatively low, so that a pressure-holding flow channel is formed on the lower half side of the core away from the feed port, which is used to hold the pressure of the extruded plastic on the lower half to make the performance more uniform and stable, and because the extruded plastic on the upper half enters the conical surface first, as the conical discharge port gradually decreases, the extruded plastic on the upper half enters the pressurized state first, The extruded plastic on the lower side is still in a pressure-maintaining state, so part of the extruded plastic on the upper side will move toward the lower side, thereby improving the overall performance of the extruded plastic on the upper and lower sides, and making the ring formed by the extruded plastic more uniform and stable. In addition, the extruded plastic on the upper side takes a longer time to start pressurization and a longer pressurization distance, while the extruded plastic on the lower side has a short pressurization distance, and a rapid pressurization contraction will be formed on the conical surface of the rear half, thereby also improving the performance of the extruded plastic on the lower side, and making the extruded rings formed on the upper and lower sides more uniform and stable.

[0010] As a preference, it also includes a series extrusion head and a hot air channel, the co-extrusion head is connected to the series extrusion head through the hot air channel, the first feed port and the second feed port of the co-extrusion head are respectively connected to the first extruder and the second extruder, and the series extrusion head is connected to the third extruder. The hot air channel is located between the series extrusion head and the co-extrusion head, the cable core first passes through the series extrusion head, and forms a cable outer sheath outside the cable core, and then enters the hot air channel for insulation and temperature rise, so that the temperature of the cable outer sheath outside the cable can adapt to the extrusion temperature of the outermost hot melt adhesive middle layer and the nylon reinforcement layer, and on the other hand, it is also convenient for the nylon reinforcement layer to be tightly combined with the cable outer sheath and the hot melt adhesive middle layer. The first feed port and the second feed port are each fed by an extruder alone, and the series extrusion head is also fed by an extruder alone, and a series extrusion method combining series extrusion and co-extrusion is adopted, so that the insulating material outside the cable can be extruded and molded at one time, thereby improving the extrusion efficiency and reducing the production cost.

[0011] Preferably, the serial extrusion head is provided with a third extrusion flow channel, the third extrusion flow channel is provided with a second closing end, and a third extrusion cavity is formed on both sides of the second closing end, so that the third extrusion cavity has the smallest diameter at the second closing end. The second closing end provided in the third extrusion flow channel in the serial extrusion head has basically the same function as the first closing end provided in the co-extrusion head, so that the extruded material is pressurized and released once in the extrusion cavity to improve the uniformity of the extruded material.

[0012] Preferably, a cooling device is provided below the co-extrusion die head, and the nylon sheathed power cable enters the cooling device through the co-extrusion die head. The cable coming out of the co-extrusion die head will be wrapped with a nylon reinforcement layer on the outermost layer to form a nylon sheathed power cable, and then cooled and formed by the cooling device to further reduce the internal stress of the entire cable.

[0013] A method for manufacturing a nylon sheathed power cable comprises the following steps: S1: adding a first material in the third extruder, wherein the first material comprises any one of PVC material, PE material, and low-smoke halogen-free polyolefin material; S2: adding a hot melt adhesive material in the first extruder; S3: adding a nylon material in the second extruder, wherein the nylon material comprises one of nylon 6 and nylon 12. The first material is used to form a cable outer sheath outside the cable core, and the hot melt adhesive material of the first extruder is used to form a hot melt adhesive intermediate layer, which can form a tight structure with the cable outer sheath on the one hand, and can also make the external nylon reinforcement layer closely combined with it on the other hand; and the cable outer sheath is extruded and formed separately by the third extruder and wrapped around the outside of the cable core; nylon has good mechanical properties, wherein nylon 6 has superior mechanical properties, stiffness, toughness, wear resistance and mechanical shock absorption, as well as good insulation and chemical resistance; nylon 12 is a good electrical insulator, similar to other polyamides, and its insulation performance will not be affected by moisture, and it has good impact resistance and chemical stability.

[0014] Preferably, the temperature in the hot air channel is 10°C to 15°C higher than the temperature of the co-extrusion die head. The cable outer sheath outside the cable core enters the hot air channel for insulation and temperature rise, which, on the one hand, enables the temperature of the outer sheath outside the cable to adapt to the extrusion temperature of the outermost nylon reinforcement layer, and on the other hand, facilitates the close combination of the nylon reinforcement layer, the cable outer sheath and the hot melt adhesive intermediate layer.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) improving the mechanical protection function of the cable sheath and preventing the sheath reinforcement layer from wrinkling, deforming and failing; (2) effectively solving the problem of large extrusion temperature difference between the nylon reinforcement layer and the cable outer sheath, which makes it impossible to adopt a co-extrusion production mode; (3) by using the co-extrusion process of the hot melt adhesive middle layer and the nylon reinforcement layer, the thickness of the hot melt adhesive middle layer can be minimized while enhancing the mutual fusion and tight combination of the hot melt adhesive middle layer and the cable outer sheath, thereby reducing the amount of hot melt adhesive and controlling the cost; (4) effectively controlling the added ratio of nylon, fully mixing and extruding, reducing the amount of nylon and reducing the labor intensity of manual mixing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional schematic diagram of the coextrusion die head of the present invention.

[0017] Figure 2 It is a schematic diagram of the coextrusion die head of the present invention.

[0018] Figure 3 It is an enlarged schematic diagram of the first closing portion of the present invention.

[0019] Figure 4 for Figure 1 Section view along AA direction.

[0020] Figure 5 It is a cross-sectional schematic diagram of the serial extrusion die head of the present invention.

[0021] Figure 6 It is a schematic diagram of the overall structural connection of the present invention.

[0022] Figure 7 It is a schematic structural diagram of the first extruder of the present invention.

[0023] Figure 8 It is a schematic cross-sectional view of the nylon sheathed power cable of the present invention.

[0024] In the figure: 1. co-extrusion head, 2. first extrusion flow channel, 3. first closing mouth, 4. first extrusion cavity, 5. second extrusion cavity, 6. first feed port, 7. second feed port, 8. second extrusion flow channel, 9. co-extrusion head discharge port, 10. adjustment block, 11. cambered convexity, 12. first mold core, 13. pressure holding flow channel, 14. serial extrusion head, 15. hot air channel, 16. first extruder, 17. second extruder, 18. third extruder, 19. third extrusion flow channel, 20. second closing mouth, 21. hopper, 22. cooling device, 23. nylon sheathed power cable, 24. third feed port, 25. .Cable core, 25.1. Insulated core, 25.2. Filling layer, 25.3. Lining layer, 26. Reinforced comprehensive sheath, 26.1. Cable outer sheath, 26.2. Hot melt adhesive middle layer, 26.3. Nylon reinforcement layer, 27. Co-extrusion head shell, 28. First cable channel layer, 29. Separation layer, 30. Connecting block, 31. First guide surface, 32. Second guide surface, 33. Screw hole, 34. Adjusting nut, 35. Mold sleeve, 36. Serial extrusion head shell, 37. Second cable channel layer, 38. Extrusion screw, 39. Serial extrusion head discharge port, 40. Second mold core, 41. Extrusion port. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0026] Embodiment 1: A nylon sheathed power cable manufacturing device, such as Figures 1 to 7As shown, it includes a co-extrusion system, a serial extrusion system and a cooling device 22, wherein the co-extrusion system includes a co-extrusion head 1, and the co-extrusion head 1 is connected to a first extruder 16 and a second extruder 17, the first extruder 16 is connected to a first feed port 6 of the co-extrusion head 1, the second extruder 17 is connected to a second feed port 7 of the co-extrusion head 1, and the first feed port 6 is perpendicular to the axial arrangement of the co-extrusion head 1, and the second feed port 7 is inclined to the axial arrangement of the co-extrusion head 1, the flow direction of the extruded material inside the co-extrusion head 1 is opposite to the feeding direction of the second feed port 7 and forms an angle of 45°, the first feed port 6 is located on the cable inlet side of the co-extrusion head 1, and the second feed port 7 is away from the cable inlet of the co-extrusion head 1 relative to the first feed port 6. The serial extrusion system includes a serial extrusion head 14, which is connected to the co-extrusion head 1 through a hot air channel 15, and the hot air channel 15 is located between the serial extrusion head discharge port 39 and the co-extrusion head 1 cable inlet, and the serial extrusion head 14 is provided with a third feed port 24, and the serial extrusion head 14 is also connected with a third extruder 18, and the third extruder 18 is connected with the third feed port 24, and the lower position of the co-extrusion head 1 is provided with a cooling device 22, and specifically, the cooling device 22 of this embodiment adopts a water tank structure. The cable core 25 first enters the serial extrusion head 14 from the end of the serial extrusion head 14 away from the serial extrusion head discharge port 39, passes through the hot air channel 15 and the co-extrusion head 1 in turn, and finally forms a nylon sheathed power cable 23 and enters the water tank for cooling, thereby completing the manufacture of the nylon sheathed power cable 23.

[0027] like Figure 8 As shown, the structure of the nylon sheathed power cable 23 includes a cable core 25 and a reinforced comprehensive sheath 26, wherein the cable core 25 includes an insulating core 25.1, a filling layer 25.2 and an inner lining layer 25.3, wherein the insulating core 25.1 is a twisted structure of one or three strands; and the reinforced comprehensive sheath 26 includes a cable outer sheath 26.1 disposed outside the inner lining layer 25.3, a hot melt adhesive intermediate layer 26.2 located outside the cable outer sheath 26.2, and a nylon reinforcement layer 26.3 located outside the hot melt adhesive intermediate layer 26.2. In this solution, the first extruder 16 and the first feed port 6 are used to supply extruded plastic for extruding the hot melt adhesive intermediate layer 26.2, the second extruder 17 and the second feed port 7 are used to supply extruded plastic for extruding the nylon reinforcement layer 26.3, and the third extruder 18 and the third feed port 24 are used to supply extruded plastic for extruding the cable outer sheath 26.1.

[0028] like Figure 1 and Figure 2As shown, the co-extrusion head 1 includes a co-extrusion head shell 27, which is cylindrical as a whole. The first feed port 6 and the second feed port 7 are arranged on the co-extrusion head shell 27. A first cable channel layer 28 and a partition layer 29 are arranged inside the co-extrusion head 1. The first cable channel layer 28 is cylindrical, and the partition layer 29 is also cylindrical as a whole. The first cable channel layer 28 and the partition layer 29 are both located inside the co-extrusion head 1, and the partition layer 29 is located between the first cable channel layer 28 and the co-extrusion head shell 27. At the cable entrance position of the co-extrusion head 1, the first cable channel layer 28, the partition layer 29 and the co-extrusion head shell 27 are fixedly connected, so that the first cable channel layer 28 and the partition layer 29 are structurally stable inside the co-extrusion head 1 and are not prone to position changes. A first extrusion flow channel 2 is formed between the partition layer 29 and the first cable channel layer 28, and a second extrusion flow channel 8 is formed between the partition layer 29 and the inner side of the co-extrusion head housing 27. The first extrusion flow channel 2 is used for extruding to form the hot melt adhesive intermediate layer 26.2, and the second extrusion flow channel 8 is used for extruding to form the nylon reinforcement layer 26.3. A through hole structure is provided at the position of the partition layer 29 corresponding to the first feed port 6, so that the first feed port 6 can pass through the partition layer 29 and connect to the first extrusion flow channel 2 between the partition layer 29 and the first cable channel layer 28.

[0029] On the half side of the coextrusion head 1 close to the first feed port 6 or the second feed port 7 ( Figure 1 or Figure 2 The first extrusion flow channel 2 and the second extrusion flow channel 8 are formed from the first feed port 6, and the co-extrusion head 1 is far from the first feed port 6 or the second feed port 7 ( Figure 1 or Figure 2 In the middle and lower half), the first extrusion flow channel 2 and the second extrusion flow channel 8 are both formed later, so that the connection area between the first cable channel layer 28 and the separation layer 29, and the connection area between the separation layer 29 and the inner side of the co-extrusion head shell 27 are increased, thereby making the connection between the separation layer 29, the first cable channel layer 28 and the co-extrusion head shell 27 more stable, avoiding the uneven extrusion pressure inside the co-extrusion head 1 causing radial offset of the separation layer 29 and the first cable channel layer 28, which causes the finally formed hot melt adhesive middle layer 26.2 or nylon reinforcement layer 26.3 to be eccentric, thereby reducing the overall performance of the nylon sheathed power cable 23.

[0030] Among them, a first closing mouth 3 is arranged in the first extrusion flow channel 2, and the first closing mouth 3 enables the first extrusion flow channel 2 to form a first extrusion cavity 4 and a second extrusion cavity 5 on both sides of the first closing mouth 3, the first extrusion cavity 4 is close to the first feed port 6, and the second extrusion cavity 5 is close to the co-extrusion head discharge port 9. The aperture of the first extrusion cavity 4 gradually decreases from the first feed port 6 to the first closing mouth 3, and the aperture between the second extrusion cavity 5 and the first closing mouth 3 gradually increases, and an expansion is formed along the flow direction of the extruded material of the hot melt adhesive intermediate layer 26.2, and then a flow channel with a constant aperture is formed; specifically, Figure 3 As shown, a certain taper structure is formed on the outside of the first cable channel layer 28 and on one side of the first extrusion cavity 4, and the taper angle is 2°, while the expanded cone formed at the second extrusion cavity 5 and the first closing 3 has a taper angle of 20°; the extruded plastic of the hot melt adhesive intermediate layer 26.2 enters the first extrusion cavity 4 after entering from the first feed port 6, and as the aperture of the first extrusion cavity 4 gradually decreases, the pressure between the extruded plastics of the hot melt adhesive intermediate layer 26.2 gradually increases, so that the extruded plastics of the hot melt adhesive intermediate layer 26.2 form a denser structure, and after the extruded plastics of the hot melt adhesive intermediate layer 26.2 pass through the first closing 3, they enter the second The aperture of the extrusion cavity 5 and the second extrusion cavity 5 suddenly increases. At this time, the hot melt adhesive middle layer 26.2 extruded plastic loses the pressure effect, thereby producing a certain expansion and releasing its internal stress, so that the adhesion effect and mechanical properties of the hot melt adhesive middle layer 26.2 extruded plastic on the outside of the cable outer sheath 26.1 are stronger; at the same time, the aperture of the second extrusion cavity 5 at the first closing end 3 suddenly increases, which can also prevent the hot melt adhesive middle layer 26.2 extruded plastic from being squeezed and broken during long-distance movement, thereby avoiding the intermittent and uneven structure of the hot melt adhesive middle layer 26.2 outside the cable outer sheath 26.1 and poor adhesion.

[0031] The second extrusion flow channel 8 is located at the periphery of the first extrusion flow channel 2, that is, between the partition layer 29 and the inner side of the co-extrusion head shell 27. The second feed port 7 is directly connected to the second extrusion flow channel 8. The second extrusion flow channel 8 is arranged in the horizontal direction, and a 45° angle is formed between the second feed port 7 and the second extrusion flow channel 8, so that the extruded plastic of the nylon reinforcement layer 26.3 of the second feed port 7 can produce a hedging effect when entering the second extrusion flow channel 8. On the one hand, the extruded plastic of the nylon reinforcement layer 26.3 is reversed. During the reversing process, the extruded plastic of the nylon reinforcement layer 26.3 needs to move in the opposite direction, so that the extruded plastic of the nylon reinforcement layer 26.3 is more uniform. On the other hand, the extruded plastic of the nylon reinforcement layer 26.3 can also form a part of the extruded plastic of the nylon reinforcement layer 26.3 on the side away from the co-extrusion head discharge port 9, and increase the half side of the co-extrusion head 1 away from the second feed port 7 ( Figure 1 or Figure 2The amount of nylon reinforcement layer 26.3 extruded material on the lower half (as shown in the figure) can be reduced, so that the nylon reinforcement layer 26.3 extruded material can form a ring-shaped extruded material with a more uniform and stable density in the second extrusion channel 8, and at the same time, it can also avoid that most of the nylon reinforcement layer 26.3 extruded material near the second feed port 7 directly enters the second extrusion channel 8 and moves directly toward the co-extrusion head discharge port 9, thereby avoiding uneven distribution of the nylon reinforcement layer 26.3 and poor mechanical properties.

[0032] A connecting block 30 is also provided on the half side of the second extrusion channel 8 close to the second feed port 7. The connecting block 30 connects the partition layer 29 and the inner wall of the co-extrusion head shell 27. The connecting block 30 is a long narrow strip and does not affect the flow of the extruded material in the second extrusion channel 8. In addition, one or two connecting blocks 30 are generally provided, mainly to make the position between the inner wall of the co-extrusion head shell 27 and the partition layer 29 relatively stable, and to reduce the radial displacement of the partition layer 29 caused by the extrusion pressure when extruding the material through the second feed port 7. Since the second extrusion channel 8 is formed by delaying the half side away from the second feed port 7, the structural position of this side is relatively stable.

[0033] like Figure 2 As shown, since the first extrusion flow channel 2 and the second extrusion flow channel 8 are delayed to form corresponding flow channels on the half side away from the first feed port 6 or the second feed port 7, in order to ensure that the first extrusion flow channel 2 and the second extrusion flow channel 8 on the half side away from the first feed port 6 or the second feed port 7 can obtain sufficient extruded plastic, the first guide surface 31 and the second guide surface 32 arranged obliquely are provided at the outer circumference of the first cable channel layer 28 and the partition layer 29. The first guide surface 31 and the second guide surface 32 are the starting surfaces of the half side of the first extrusion flow channel 2 and the second extrusion flow channel 8 away from the first feed port 6 or the second feed port 7, respectively.

[0034] The first extrusion flow channel 2 and the second extrusion flow channel 8 are connected at their outlets, so that after the hot melt adhesive middle layer 26.2 extruded material and the nylon reinforcement layer 26.3 extruded material flow out from the first extrusion flow channel 2 and the second extrusion flow channel 8 respectively, the nylon reinforcement layer 26.3 will be coated on the periphery of the hot melt adhesive middle layer 26.2 and form a tight combination with the cable outer sheath 26.1, realizing the double-layer co-extrusion operation of the hot melt adhesive middle layer 26.2 and the nylon reinforcement layer 26.3.

[0035] A plurality of adjustment blocks 10 are also arranged inside the co-extrusion die housing 27. The adjustment blocks 10 are evenly distributed along the circumference of the co-extrusion die housing 27. Figure 1 and Figure 4As shown, there are four adjusting blocks 10, four screw holes 33 are opened on the co-extrusion head shell 27, and adjusting nuts 34 are arranged in the screw holes 33. The adjusting nuts 34 are connected to the adjusting blocks 10, and rotating the adjusting nuts 34 can make the adjusting blocks 10 slide radially along the co-extrusion head shell 27. The adjusting blocks 10 are in an arc-shaped structure. The adjusting blocks 10 are arranged before the confluence of the first extrusion flow channel 2 and the second extrusion flow channel 8. The side of the adjusting block 10 close to the second extrusion flow channel 8 is in the shape of an arc-shaped protrusion 11, so that the aperture of the second extrusion flow channel 8 from the incoming direction to the position of the adjusting block 10 is reduced, while the aperture of the other side is gradually increased. The adjusting block 10 can be used to adjust the local aperture size in the second extrusion flow channel 8, so that when the nylon reinforcement layer 26.3 extruded material in the second extrusion flow channel 8 passes through the adjusting block 10, it is first pressurized and then the pressure is released, thereby reducing the stress inside the nylon reinforcement layer 26.3 extruded material, so that the mechanical properties of the nylon reinforcement layer 26.3 extruded material after molding are higher and the performance is more stable.

[0036] For different extruded plastics located in the second extrusion flow channel 8, the overall performance of the entire extruded plastic can be improved by adjusting the radial displacement of the adjusting block 10 to change the aperture of part of the second extrusion flow channel 8. When the four adjusting blocks 10 are radially close to the axial position of the co-extrusion head 1, the four adjusting blocks 10 can form a complete circle, and there is still a flow channel between the adjusting blocks 10 and the partition layer 29 for the extruded plastic to pass through. When the four adjusting blocks 10 are radially away from the axial position of the co-extrusion head 1, the aperture of the flow channel between the adjusting blocks 10 and the partition layer 29 increases, and a radial gap can be formed between the adjusting blocks 10 for part of the extruded plastic to pass through. The effect of pressurization and pressure release can also be achieved, and the internal stress inside the extruded plastic can be reduced, so that the mechanical properties of the extruded plastic after molding are higher and the performance is more stable.

[0037] A first mold core 12 is also provided in the outlet direction of the first extrusion flow channel 2 and the second extrusion flow channel 8. The first mold core 12 is fixedly connected to the first cable channel layer 28. The interior of the first mold core 12 is in the shape of a through hole and is connected to the first cable channel layer 28, so that the cable core 25 covered with the cable outer sheath 26.1 can pass through; and a mold sleeve 35 is also provided on the side of the co-extrusion head discharge port 9. The shape of the interior of the mold sleeve 35 is adapted to the shape of the outer surface of the first mold core 12, so that a flow channel is formed between the mold sleeve 30 and the first mold core 12, so that the hot melt adhesive intermediate layer 26.2 extruded material and the nylon reinforcement layer 26.3 extruded material can pass through, so that the extruded material can finally flow out from the co-extrusion head discharge port 9 and be wrapped around the outside of the cable outer sheath 26.1.

[0038] like Figure 1As shown, the first mold core 12 is an asymmetric structure. On the half side close to the first feed port 6 or the second feed port 7, the first mold core 12 is a conical structure. On the half side away from the first feed port 6 or the second feed port 7, the first mold core 12 is first a cylindrical structure and then a conical structure in the flow direction of the extruded material, wherein a pressure holding channel 13 is formed between the cylindrical surface structure and the inner side of the mold sleeve 35 and the first extrusion channel 2 and the second extrusion channel 8. Since the first mold core 12 is close to the first feed port 6 or the second feed port 7, the extruded plastic is denser and has a more uniform and stable density, while the extruded plastic at the side of the first mold core 12 far from the first feed port 6 or the second feed port 7 is less dense and has a relatively lower consistency in density than the extruded plastic at the side closer to the first feed port 6 or the second feed port 7, so that a pressure-maintaining flow channel 13 is formed on the lower half of the first mold core 12 away from the first feed port 6 or the second feed port 7 to maintain the pressure of the extruded plastic on the lower half so that the performance is more uniform and stable; and since the extruded plastic on the upper half enters the conical surface first, as the conical surface As the size of the discharge port gradually decreases, the extruded plastic on the upper side enters the pressurized state first, while the extruded plastic on the lower side is still in the pressure-maintaining state, so that part of the extruded plastic on the upper side moves to the lower side, thereby improving the overall performance of the extruded plastic on the upper and lower sides, and making the ring-shaped extruded plastic more uniform and stable. In addition, the extruded plastic on the upper side takes a longer time to start pressurization, has a longer pressurization distance, and a slower pressurization rate, while the extruded plastic on the lower side has a short pressurization distance, and a rapid pressurization contraction will be formed on the conical surface of the rear half, thereby also improving the performance of the extruded plastic on the lower side, and making the extruded rings formed on the upper and lower sides more uniform and stable.

[0039] like Figure 5The extruder head 14 shown in the figure includes an extruder head shell 36, a third feed port 24 is arranged on the extruder head shell 36, a second cable channel layer 37 arranged horizontally is arranged inside the extruder head 14, the second cable channel layer 37 and the inner side of the extruder head shell 36 form a third extrusion flow channel 19, a second closing opening 20 is arranged inside the third extrusion flow channel 19, a flow channel with a gradually decreasing aperture is formed in the third extrusion flow channel 19 from the third feed port 24 to the second closing opening 20, and a flaring structure is formed from the second closing opening 20 to the extruder head discharge port 39, specifically, a certain taper structure is formed on the outer side of the second cable channel layer 37 and close to the third feed port 24, and the taper angle is 2°, and the flared cone formed on the side away from the third feed port 24 and the second closing opening 20 has a taper angle of 20°; cable outer sheath The extruded plastic 26.1 enters the third extrusion flow channel 19 after entering from the third feed port 24, and as the aperture of the third extrusion flow channel 19 gradually decreases, the pressure between the extruded plastic of the cable outer sheath 26.1 gradually increases, so that the extruded plastic of the cable outer sheath 26.1 forms a denser structure. After the extruded plastic of the cable outer sheath 26.1 passes through the second closing 20, the aperture of the third extrusion flow channel 19 suddenly increases. At this time, the extruded plastic of the cable outer sheath 26.1 loses the pressure effect, thereby generating a certain expansion, releasing its internal stress, thereby making the mechanical properties of the cable outer sheath 26.1 stronger; at the same time, the aperture of the third extrusion flow channel 19 suddenly increases after the second closing, which can also prevent the extruded plastic of the cable outer sheath 26.1 from being squeezed and broken during long-distance movement, thereby avoiding the intermittent and uneven structure of the cable outer sheath 26.1.

[0040] A second mold core 40 is also provided in the discharge direction of the second cable channel layer 37. The second mold core 40 is a symmetrical conical structure, and a channel is provided inside for the cable core 25 to pass through. When the cable core 25 passes through the extrusion head 14, it will be wrapped with a layer of cable outer sheath 26.1, and the cable outer sheath 26.1 will be tightly combined with the subsequent hot melt adhesive intermediate layer 26.2 and the nylon reinforcement layer 26.3.

[0041] A hot air channel 15 is also provided between the serial extrusion head 14 and the co-extrusion head 1, which heats and insulates the cable core 25 wrapped with the cable outer sheath 26.1, thereby facilitating the tight bonding of the cable outer sheath 26.1 with the outer hot melt adhesive intermediate layer 26.2 and the nylon reinforcement layer 26.3.

[0042] It should also be noted that the first extruder 16, the second extruder 17 and the third extruder 18 include a hopper 21 and an extrusion screw 38. The extrusion screw 38 is provided with an extrusion port 41 away from the hopper 21. After the extruded material is fed into the hopper 21, it enters the extrusion screw 38 for melting and stirring, and finally the extruded material is sent to the co-extrusion head 1 or the serial extrusion head 14 through the extrusion port 41.

[0043] Specifically, the cable core 25 enters the extruder head 14 under the combined action of the traction force of the pay-off traction and the take-up traction. The cable outer sheath 26.1 extruded material enters the extruder head 14 through the third extruder 18, and is extruded around the cable core 25; under the action of the traction force, the cable core 25 wrapped with the cable outer sheath 26.1 enters the hot air channel 15 for insulation, heating and stretching deformation, so that the cable outer sheath 26.1 can adapt to the extrusion temperature of the nylon reinforcement layer 26.3, and at the same time tightly wrap around the cable core 25, and the thickness of the cable outer sheath 26.1 is controlled between 2mm and 5mm; the heating and insulation temperature of the hot air channel 15 is controlled to be 10°C higher than the temperature of the extruder head 14. Under the heating and insulation effect of the hot air channel 15, the cable outer sheath 26.1 can adapt to the extrusion temperature of the nylon reinforcement layer 26.3, and enters the co-extrusion head 1 under the action of the traction force; the hot melt adhesive intermediate layer 2 The extruded material 6.2 passes through the first extruder 16, and the nylon reinforcement layer 26.3 extruded material passes through the second extruder 17 into the co-extrusion head 1, and then comes out of the co-extrusion head 1 and is coated on the outer periphery of the cable outer sheath 26.1. After the nylon reinforcement layer 26.3 is extruded, under the action of the tensile shrinkage force and the mutual penetration and fusion of the semi-molten hot melt adhesive intermediate layer 26.2, a set of tightly combined reinforced comprehensive sheath 26 is formed with the cable outer sheath 26.1, and the thickness of the hot melt adhesive intermediate layer 26.2 is controlled between 0.2mm and 0.3mm, and the thickness of the nylon reinforcement layer 26.3 is controlled between 0.4mm and 0.6mm; then, under the action of traction, it enters the water tank of the cooling device 22 for cooling and solidification, and finally forms the nylon sheath reinforced power cable 23 and is wound up on the coil.

[0044] The method for manufacturing a nylon sheathed power cable using the above-mentioned nylon sheathed power cable manufacturing device includes the following steps: first, PVC material, PE material, low-smoke halogen-free polyolefin material, or other sheath material is used as the first material and is put into the third extruder 18, and the first material is also the cable outer sheath 26.1 extrusion material, and then a hot melt adhesive material is placed in the hopper 21 of the first extruder 16. The hot melt adhesive material is mixed and stirred evenly by the extrusion screw 38 to form a hot melt adhesive middle layer 26.2 extrusion material, and is transferred to the first feed port 6 of the co-extrusion head 1, and then nylon 6 or nylon 12 material is used as the nylon reinforcement layer 26.3 extrusion material and is put into the second extruder 17, and finally the heating and insulation temperature of the hot air channel 15 is controlled to be 10°C higher than the temperature of the serial extrusion head 14, and then each extruder can be started to start working.

[0045] Since the extrusion temperatures of the material of the hot melt adhesive middle layer 26.2 and the material of the nylon reinforcement layer 26.3 are close, double-layer co-extrusion can be achieved by co-extrusion. However, the extrusion temperature of the cable outer sheath 26.1 is quite different from the extrusion temperatures of the hot melt adhesive middle layer 26.2 and the nylon reinforcement layer 26.3. Therefore, it is necessary to perform heating and insulation operations in the hot air channel 15. On the one hand, the temperature of the cable outer sheath 26.1 outside the cable core 25 can adapt to the extrusion temperature of the outermost nylon reinforcement layer 26.3. On the other hand, it is also convenient for the nylon reinforcement layer 26.3 to be tightly combined with the cable outer sheath 26.1 and the hot melt adhesive middle layer 26.2.

Claims

1. A nylon sheathed power cable manufacturing device, characterized in that: It includes a co-extrusion head, which includes a first feed port, a first extrusion channel is arranged on the co-extrusion head, a first closing port is arranged in the first extrusion channel, a first extrusion cavity and a second extrusion cavity are formed on both sides of the first closing port, the first extrusion cavity gradually decreases from the first feed port to the first closing port position, and the connection between the first closing port and the second extrusion cavity forms a flared shape.

2. A nylon sheathed power cable manufacturing device according to claim 1, characterized in that: The co-extrusion head also includes a second extrusion channel arranged on the outer periphery of the first extrusion channel and a second feed port arranged on the outer shell of the co-extrusion head. The second feed port is inclined relative to the second extrusion channel, and the feeding direction of the second feed port is opposite to the flow direction of the second extrusion channel.

3. A nylon sheathed power cable manufacturing device according to claim 2, characterized in that: The first extrusion flow channel and the second extrusion flow channel are connected to the discharge port of the co-extrusion head together. A plurality of adjustment blocks are provided on the circumference of the co-extrusion head shell. The adjustment blocks are provided at the second extrusion flow channel and are located before the first extrusion flow channel and the second extrusion flow channel are connected.

4. A nylon sheathed power cable manufacturing device according to claim 3, characterized in that: The adjusting block can slide radially along the co-extrusion die head, and a side of the adjusting block close to the second extrusion flow channel is a cambered convex structure.

5. A nylon sheathed power cable manufacturing device according to claim 4, characterized in that: A mold core is provided at the discharge port of the co-extrusion head, and the half side of the mold core close to the first feed port or the second feed port is a conical surface, and the half side of the mold core away from the first feed port or the second feed port forms a pressure holding channel together with the first extrusion runner and the second extrusion runner, and the part of the mold core located after the pressure holding channel is a conical surface.

6. A nylon sheathed power cable manufacturing device according to any one of claims 1 to 5, characterized in that: It also includes a tandem extrusion head and a hot air channel. The co-extrusion head is connected to the tandem extrusion head through the hot air channel. The first feed port and the second feed port of the co-extrusion head are respectively connected to the first extruder and the second extruder, and the tandem extrusion head is connected to the third extruder.

7. A nylon sheathed power cable manufacturing device according to claim 6, characterized in that: A third extrusion flow channel is provided in the serial extruder head, a second closing end is provided in the third extrusion flow channel, and a third extrusion cavity is formed on both sides of the second closing end, so that the third extrusion cavity has the smallest diameter at the second closing end position.

8. A nylon sheathed power cable manufacturing device according to claim 7, characterized in that: A cooling device is also provided below the co-extrusion die head, and the nylon sheathed power cable enters the cooling device through the co-extrusion die head.

9. A method for manufacturing a nylon sheathed power cable, characterized in that: The nylon sheathed power cable manufacturing device according to claim 6 is implemented, comprising the following steps S1: adding a first material to the third extruder, wherein the first material includes any one of PVC material, PE material, and low-smoke halogen-free polyolefin material; S2: adding hot melt adhesive material into the first extruder; S3: Adding nylon material, including nylon 6 or nylon 12, into the second extruder.

10. A method for manufacturing a nylon sheathed power cable according to claim 9, characterized in that: The temperature in the hot air channel is 10° C. to 15° C. higher than the temperature of the extruder head.

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