Communication cable and cooling device for its production

Abstract

The present application relates to a kind of communication cables, including including core wire and the sheath that is covered outside core wire, it is related to cable technical field, sheath is formed by gradient temperature cooling process, gradient temperature cooling process includes the three stages of high-temperature zone cooling (80 ℃±5 ℃), medium-temperature zone cooling (30 ℃±2 ℃) and low-temperature zone cooling (‑78 ℃±3 ℃) in turn;Sheath material is low-temperature modified material, when using polyvinyl chloride material, the low-temperature embrittlement temperature of polyvinyl chloride material is not less than-48 ℃, when using polyethylene material, polyethylene material still keeps good toughness at-78 ℃;Interface adhesion between core wire and sheath is optimized by gradient temperature control.The gradient cooling mechanism of the present application makes the interface molecular chain between sheath and core wire fully relaxed, and crystallization behavior is controllable, thereby realizes the high uniformity of adhesion on the length of whole cable, and peeling force is accurately controlled in the ideal interval of 0.5-2N / mm.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and in particular to a communication cable and a cooling device for its production. Background Technology

[0002] Cooling devices in communication cable production are indispensable key process equipment after cable extrusion molding. Their core function is to rapidly and uniformly cool and shape the high-temperature molten sheath (typically 160–200℃) immediately after exiting the extruder, resulting in finished cables with stable dimensions, smooth surfaces, and satisfactory mechanical properties. Traditional cooling devices generally employ single- or double-stage water tank structures, filled with room-temperature water (approximately 20–30℃) or slightly temperature-controlled circulating water. The cable is immersed in this water by rollers to achieve cooling. Some high-speed production lines may supplement this with spray systems or air-cooling sections, but the overall focus remains solely on "rapid cooling," lacking precise control over the thermodynamic behavior of the cooling process.

[0003] However, this extensive cooling method suffers from a series of deep-seated technical defects, which stem directly from the mismatch between the cooling rate and the thermophysical properties of the material. For example, in traditional single-stage water cooling, when the high-temperature sheath (such as PVC, 180°C) is instantly exposed to cooling water below 30°C, the outer layer rapidly solidifies to form a hard shell, while the inner layer remains in a highly elastic or even viscous state. As heat continues to be conducted from the inside to the outside, the inner layer material is constrained by the solidified outer layer during contraction, generating significant radial tensile stress and circumferential compressive stress. This unbalanced cooling process creates an irreversible residual thermal stress field inside the cable.

[0004] If this problem is not resolved, it can easily lead to the sheath becoming eccentric or elliptical, and the uneven stress distribution can cause the cable cross-section to become out of round, affecting the subsequent cabling accuracy and shielding performance. And microcracks or crazing, because especially in bending or low-temperature environments, residual stress combined with external loads can easily cause cracks to initiate on the surface or interface of the sheath. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a communication cable and a cooling device for its production, which can effectively solve the aforementioned problems.

[0006] To achieve the above requirements, the technical solution adopted by the present invention to solve its technical problem is as follows: A communication cable is provided, including a core wire and a sheath covering the outside of the core wire. The sheath is formed by a gradient temperature cooling process, which includes three stages performed sequentially: high temperature cooling (80℃±5℃), medium temperature cooling (30℃±2℃), and low temperature cooling (-78℃±3℃). The sheath material is a low-temperature resistant modified material. When polyvinyl chloride (PVC) is used, the low-temperature embrittlement temperature of the PVC material is not lower than -48°C. When polyethylene (PE) is used, the polyethylene material still maintains good toughness at -78°C. The interfacial adhesion between the core wire and the sheath is optimized by gradient temperature control and remains uniform along the entire length of the cable. The peel force of the sheath is controlled within the range of 0.5-2 N / mm.

[0007] In a preferred embodiment of this scheme, when the sheath material is polyvinyl chloride (PVC), the polyvinyl chloride material comprises, by weight, the following components: 100 parts PVC resin, 40-75 parts composite plasticizer, 0.4-1.6 parts composite lubricant, 15-25 parts composite flame retardant, 5-12 parts calcium-zinc stabilizer, 6-10 parts modified calcined clay, 8-12 parts vinyl acetate-propylene block copolymer, and 40-70 parts spherical nano-active calcium.

[0008] In this preferred embodiment, the degree of polymerization of the polyvinyl chloride resin is 1250-1350, the composite plasticizer includes a mixture of dioctyl terephthalate (DOTP), phthalate plasticizers, and dioctyl sebacate (DOS), and the composite lubricant includes a mixture of high-melting-point oxidized polyethylene wax lubricant and stearic acid lubricant.

[0009] In a preferred embodiment of this scheme, the core wire adopts a multi-strand stranded structure, which includes a central tensile steel wire and multiple conductors stranded around the central tensile steel wire; The stranding direction of the conductor is consistent with the extrusion direction of the sheath, and the stranding pitch of the conductor is 10-15 times the diameter of the conductor. A gradient filler layer is provided between the core wire and the sheath, and the material density of the gradient filler layer gradually decreases from the core wire side to the sheath side.

[0010] A cooling device for manufacturing communication cables includes a high-temperature cooling box, a medium-temperature cooling box, a low-temperature cooling box, and a cleaning box arranged in sequence. The top of the high-temperature cooling box is provided with a protective cover, and a magnetic regenerator is installed through the protective cover. The medium-temperature cooling box contains water for water cooling. The low-temperature cooling box contains liquid nitrogen. The cleaning box contains cleaning water for cleaning the outer wall of the cable sheath.

[0011] In this preferred embodiment, a second conveyor shaft is provided on both sides of the top of the high-temperature zone cooling box, the medium-temperature zone cooling box, the low-temperature zone cooling box, and the cleaning box. A fixed ear plate seat is installed at the top edge of the high-temperature zone cooling box, the medium-temperature zone cooling box, the low-temperature zone cooling box, and the cleaning box. A second conveyor shaft is rotatably installed between two opposite fixed ear plate seats. Ear plates are symmetrically welded to the top of the side of the high-temperature zone cooling box facing away from the medium-temperature zone cooling box. A first conveyor shaft is rotatably installed between two ear plates. The protective top cover has inlets and outlets on both sides, and each inlet and outlet has an anti-wear silicone gasket bonded to its inner wall. The high-temperature zone cooling box, the medium-temperature zone cooling box, the low-temperature zone cooling box, and the cleaning box are mounted on the cooling frame.

[0012] In this preferred embodiment, a third transmission shaft is rotatably installed in the lower part of the inner cavity of the high-temperature zone cooling box, the medium-temperature zone cooling box, the low-temperature zone cooling box, and the cleaning box. The cable sheath is conveyed from the first transmission shaft to the inlet and outlet at the top of the high-temperature zone cooling box, enters the high-temperature zone cooling box, is conveyed by the third transmission shaft in the high-temperature zone cooling box, and is pulled out from the inlet and outlet on the other side of the protective top cover. Subsequently, it is conveyed by the remaining second transmission shafts in sequence, extending through the medium-temperature zone cooling box, the low-temperature zone cooling box, and the cleaning box.

[0013] In this preferred embodiment, a servo motor is embedded in the inner bottom wall of the high-temperature cooling box. The top output shaft of the servo motor is connected to a chassis. A cross support is fixed on the top surface of the chassis. A cross cleaning brush is fixed on the top surface of the cross support. When the servo motor drives the chassis to rotate, the cross cleaning brush actively cleans the outer wall of the cable during the transmission process. The inner wall of the high-temperature zone cooling box near the medium-temperature zone cooling box is also provided with two oppositely arranged wiping cotton pads for wiping the cleaned cables. The two wiping cotton pads hold the cables and the cables are transmitted through friction between the two wiping cotton pads. Each wiping cotton pad has a fixed base plate on its back, and both ends of each fixed base plate are fixed to the inner walls of both sides of the high-temperature zone cooling box.

[0014] In a preferred embodiment, a cleaning cotton sleeve is fixedly fitted around the second transmission shaft on the side of the cleaning box away from the low-temperature cooling box. An inverted U-shaped frame rod is fixed above the cleaning cotton sleeve and above the two adjacent fixed ear plates. An electric lifting rod is longitudinally installed on the inner top wall of the U-shaped frame rod. A lifting base plate is fixed at the bottom lifting end of the electric lifting rod. A cleaning cotton block is fixed on the bottom surface of the lifting base plate. The outer wall of the cable sheath is clamped and rubbed between the cleaning cotton block and the cleaning cotton sleeve.

[0015] In this preferred embodiment, positioning poles are welded to both sides of the electric lifting rod and to the top surface of the lifting base plate. The tops of the two positioning poles extend upward to the outside of the U-shaped frame. Two connecting plates are symmetrically installed on one inner wall of the high-temperature zone cooling box, medium-temperature zone cooling box, low-temperature zone cooling box, or cleaning box. A tensioning roller is rotatably installed between the two connecting plates. The outer wall of the cable sheath passes through the tensioning roller.

[0016] The beneficial effects of this invention are as follows: This communication cable and its production cooling device employ a gradient temperature cooling process (80℃±5℃ → 30℃±2℃ → –78℃±3℃) in synergy with a low-temperature modified sheath material. This allows the sheath to undergo a three-stage thermal history during cooling: slow cooling, shaping, and cryogenic strengthening. This effectively simulates the natural annealing process of polymer materials, avoiding the residual thermal stress caused by rapid outer layer solidification and continuous inner layer shrinkage resulting from traditional single-stage water or air cooling. This gradient cooling mechanism allows for sufficient relaxation of the molecular chains at the interface between the sheath and the core wire, and controllable crystallization behavior. This achieves highly uniform adhesion along the entire cable length and precisely controls the peel force within the ideal range of 0.5–2 N / mm. Compared to existing technologies where excessively rapid cooling rates lead to "local delamination" or "difficulty in opening the sheath," this solution ensures both the structural integrity and tensile strength of the cable during use, while also meeting the stringent requirements for easy peeling in subsequent automated processing (such as stripping and termination), achieving a dual optimization of performance and processability. By employing a multi-layered composite structure design that sequentially incorporates an insulating sheath, a gradient filler layer, and a fire-retardant sheath around the core wire, heat can be conducted radially from the inside out layer by layer during cooling. The density of the gradient filler layer gradually decreases from the core wire side to the sheath side, creating a thermal conductivity gradient field that guides uniform heat diffusion and avoids stress concentration at the interface caused by differences in thermal expansion coefficients. This structure, coupled with the gradient cooling process, further enhances cooling uniformity. Compared to existing single-layer or homogeneous filler structures, this solution significantly reduces the risks of sheath eccentricity and uneven internal stress distribution, improves cable roundness and electrical consistency, and is particularly suitable for high-frequency, high-speed communication scenarios. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a schematic diagram of the cable structure of the present invention; Figure 2This is a schematic diagram of the cooling device of the present invention; Figure 3 This is a schematic diagram of the structure of the wiping cotton pad of the present invention; Figure 4 This is a schematic diagram of the connection structure of the cross-shaped cleaning brush of the present invention; Figure 5 This is a schematic diagram of the installation structure of the cleaning cotton sleeve and cleaning cotton block of the present invention.

[0018] Explanation of reference numerals in the attached figures: In the diagram: 1. Core wire; 2. Sheath; 3. Insulating sleeve; 4. Gradient filler layer; 5. Fire-retardant sleeve; 6. Cooling frame; 7. High-temperature cooling box; 8. Medium-temperature cooling box; 9. Low-temperature cooling box; 10. Cleaning box; 11. Protective top cover; 12. Magnetic regenerator; 13. Inlet and outlet; 14. Anti-wear silicone gasket; 15. Ear plate; 16. First transmission shaft; 17. Fixed ear plate seat; 18. Second transmission shaft; 19. Connecting plate; 20. Tensioning roller shaft; 21. U-shaped support pole; 22. Cross-shaped cleaning brush; 23. Wiping pad; 24. Fixed base plate; 25. Cross-shaped support; 26. Chassis; 27. Servo motor; 28. Cleaning cotton sleeve; 29. ​​Cleaning cotton block; 30. Lifting base plate; 31. Electric lifting pole; 32. Positioning pole; 33. Third transmission shaft. Detailed Implementation

[0019] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] "Multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0022] Furthermore, the terms indicating orientation, such as "up," "down," "left," "right," "upper end," "lower end," and "longitudinal," are all based on the posture and position of the device or equipment described in this solution during normal use.

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0024] This embodiment discloses, as follows: Figures 1 to 5 The communication cable shown includes a core wire 1 and a sheath 2 covering the outside of the core wire 1; The sheath 2 is formed by a gradient temperature cooling process, which includes three stages: high temperature cooling (80℃±5℃), medium temperature cooling (30℃±2℃), and low temperature cooling (-78℃±3℃). The sheath material 2 is a low-temperature resistant modified material. When polyvinyl chloride (PVC) is used, the low-temperature embrittlement temperature of PVC is not lower than -48℃. When polyethylene (PE) is used, PE still maintains good toughness at -78℃. The interfacial adhesion between the core wire 1 and the sheath 2 is optimized through gradient temperature control, maintaining uniformity across the entire length of the cable. The peel force of the sheath 2 is controlled within the range of 0.5-2 N / mm. An insulating sleeve 3 is provided on the outer wall of the core wire 1, and a fire-retardant sleeve 5 is provided between the gradient filler layer 4 and the sheath 2. This gradient design simulates the natural cooling process of the material, effectively releasing internal stress and avoiding the problem of uneven adhesion between the sheath and the core wire caused by traditional rapid cooling.

[0025] In this embodiment, when the sheath 2 is made of polyvinyl chloride (PVC), the PVC material comprises, by weight, 100 parts PVC resin, 40-75 parts composite plasticizer, 0.4-1.6 parts composite lubricant, 15-25 parts composite flame retardant, 5-12 parts calcium-zinc stabilizer, 6-10 parts modified calcined clay, 8-12 parts vinyl acetate-propylene block copolymer, and 40-70 parts spherical nano-active calcium. The sheath material maintains good mechanical strength while significantly improving low-temperature toughness and thermal stability. The composite plasticizer (DOTP / DOS, etc.) exhibits excellent migration resistance and low-temperature flexibility, the spherical nano-active calcium not only enhances the filling effect but also improves interfacial compatibility, and the vinyl acetate-propylene block copolymer acts as an impact modifier to effectively inhibit low-temperature brittleness. This formulation system enables the PVC sheath to maintain molecular chain mobility even in a cryogenic environment of -78°C, preventing the formation of microcracks. Compared with existing general-purpose PVC formulations, it achieves the effect of not becoming brittle, not cracking, and maintaining dimensional stability under extreme gradient cooling conditions, providing a reliable material guarantee for the implementation of low-temperature cooling processes.

[0026] In this embodiment, the degree of polymerization of the polyvinyl chloride resin is 1250-1350. The composite plasticizer includes a mixture of dioctyl terephthalate (DOTP), phthalate plasticizers, and dioctyl sebacate (DOS). The composite lubricant includes a mixture of high-melting-point oxidized polyethylene wax lubricant and stearic acid lubricant. The melt exhibits suitable viscoelasticity and flowability during extrusion, while displaying more controllable crystallization kinetics during the cooling stage. The high-polymerization-degree resin provides a high-strength skeleton, while the combination of high-melting-point oxidized polyethylene wax and stearic acid lubricant effectively prevents the sheath surface from sticking to the transmission shaft during cooling in the high-temperature zone (80°C) and avoids excessive precipitation leading to interface weakening in the low-temperature zone. Compared with traditional single lubrication systems, this achieves a comprehensive effect of smooth extrusion, smooth surface, and stable adhesion during cooling, significantly improving the appearance quality and batch consistency of the cable.

[0027] In this embodiment, the core wire 1 adopts a multi-strand stranded structure, which includes a central tensile steel wire and multiple conductors stranded around the central tensile steel wire; The stranding direction of the conductor is consistent with the extrusion direction of the sheath 2, and the stranding pitch of the conductor is 10-15 times the conductor diameter; A gradient filler layer 4 is provided between the core wire 1 and the sheath 2. The material density of the gradient filler layer 4 gradually decreases from the core wire 1 side to the sheath 2 side. During the cooling and pulling process, the cable experiences uniform stress. The conductor stranding direction is consistent with the sheath extrusion direction, reducing torsional stress transmission. The pitch of 10–15 times the conductor diameter optimizes flexibility and structural stability. The gradient filler layer 4, with its decreasing density from the inside to the outside, forms a thermal resistance gradient, guiding heat to be conducted orderly from the core to the outside of the sheath, avoiding localized overheating or uneven cooling. Compared with existing homogeneous filler or unfilled structures, this achieves more uniform heat flow distribution, reduced sheath eccentricity, and more stable high-frequency signal transmission performance, making it particularly suitable for applications with stringent electrical consistency requirements, such as 5G and data centers.

[0028] A cooling device for communication cable production includes a high-temperature cooling box 7, a medium-temperature cooling box 8, a low-temperature cooling box 9, and a cleaning box 10 arranged sequentially. The high-temperature cooling box 7 has a protective top cover 11, through which a magnetic regenerator 12 is installed. The medium-temperature cooling box 8 contains water for cooling, the low-temperature cooling box 9 contains liquid nitrogen, and the cleaning box 10 contains cleaning water for cleaning the outer wall of the cable sheath 2. The cable undergoes a complete process of slow cooling → water cooling shaping → cryogenic strengthening → final cleaning. Liquid nitrogen vaporization temperature control achieves a precise low-temperature environment of -78℃±3℃, far exceeding the cooling limits of traditional air cooling or single water cooling. Compared with existing single-tank or dual-stage cooling devices, it achieves a finer cooling gradient, more thorough thermal stress release, and more precise adhesion control, while integrating the cleaning function at the end of the production line, eliminating the need for a separate cleaning process.

[0029] In this embodiment, a second conveyor shaft 18 is provided on both sides of the top of the high temperature zone cooling box 7, the medium temperature zone cooling box 8, the low temperature zone cooling box 9, and the cleaning box 10. A fixed ear plate seat 17 is installed at the top edge of the high temperature zone cooling box 7, the medium temperature zone cooling box 8, the low temperature zone cooling box 9, and the cleaning box 10. The second conveyor shaft 18 is rotatably installed between two opposite fixed ear plate seats 17. Ear plates 15 are symmetrically welded to the top of the side of the high temperature zone cooling box 7 facing away from the medium temperature zone cooling box 8. A first conveyor shaft 16 is rotatably installed between two ear plates 15. The protective top cover 11 has inlets and outlets 13 on both sides, and each inlet and outlet 13 has an anti-wear silicone gasket 14 bonded to its inner wall. The high-temperature cooling box 7, the medium-temperature cooling box 8, the low-temperature cooling box 9, and the cleaning box 10 are mounted on the cooling rack 6. The cable travels smoothly in an S-shaped path within each cooling box, extending the dwell time and ensuring full immersion; the silicone gaskets effectively buffer the friction between the cable and the metal edges, preventing surface scratches. Compared to the existing simple roller traction method, this achieves stable cable tension, no shaking or deviation, and no mechanical damage to the surface, ensuring the integrity of the high-gloss sheath.

[0030] In this embodiment, a third transmission shaft 33 is rotatably installed in the lower part of the inner cavity of the high-temperature zone cooling box 7, the medium-temperature zone cooling box 8, the low-temperature zone cooling box 9, and the cleaning box 10. The cable sheath 2 is conveyed from the first transmission shaft 16 to the inlet / outlet 13 at the top of the high-temperature zone cooling box 7, enters the high-temperature zone cooling box 7, is conveyed by the third transmission shaft 33 in the high-temperature zone cooling box 7, and is pulled out from the other side of the protective top cover 11 through the inlet / outlet 13. Then, it is sequentially conveyed by the remaining second transmission shafts 18 and extends through the medium-temperature zone cooling box 8, the low-temperature zone cooling box 9, and the cleaning box 10.

[0031] In this embodiment, a servo motor 27 is embedded in the inner bottom wall of the high-temperature cooling box 7. The top output shaft of the servo motor 27 is connected to the chassis 26. A cross support 25 is fixed on the top surface of the chassis 26. A cross cleaning brush 22 is fixed on the top surface of the cross support 25. When the servo motor 27 drives the chassis 26 to rotate, the cross cleaning brush 22 actively cleans the outer wall of the cable during the transmission process. The inner wall of the high-temperature cooling box 7, near the medium-temperature cooling box 8, is equipped with two opposing wiping pads 23 for wiping the cleaned cable. The two pads 23 clamp the cable, allowing it to be rubbed between them. Each pad 23 has a fixed base plate 24 on its back, and both ends of each base plate 24 are fixed to the inner walls of the high-temperature cooling box 7. Impurities on the surface of the freshly extruded, still softened sheath 2 can be efficiently brushed away at high temperatures, followed by polishing through clamping wiping. This two-stage cleaning mechanism of "rotary brushing + friction wiping" completes surface purification in the early cooling stage, preventing stains from hardening and becoming difficult to remove. Compared to existing passive cleaning methods that rely solely on subsequent water washing, this achieves higher surface cleanliness, eliminates residual oxides or oil, and improves the adhesion of subsequent printing.

[0032] In this embodiment, a cleaning cotton sleeve 28 is fixedly sleeved around the second transmission shaft 18 on the side of the cleaning box 10 away from the low-temperature cooling box 9. An inverted U-shaped support rod 21 is fixed above the cleaning cotton sleeve 28 and above each of the two adjacent fixed ear plate seats 17. An electric lifting rod 31 is longitudinally installed on the inner top wall of the U-shaped support rod 21. A lifting base plate 30 is fixed to the bottom lifting end of the electric lifting rod 31. A cleaning cotton block 29 is fixed to the bottom surface of the lifting base plate 30. The outer wall of the cable sheath 2 is clamped and rubbed between the cleaning cotton block 29 and the cleaning cotton sleeve 28. The cable undergoes a final precision wipe before output. The electric lifting rod 31 can automatically adjust the clamping pressure according to the cable diameter to avoid damage from overpressure or insufficient cleaning due to underpressure. Compared with the existing fixed pressure wiping structure, this achieves the effects of adaptive cleaning force, thorough surface drying, and no water stain residue, meeting the stringent standards for surface cleanliness of high-end communication cables.

[0033] In this embodiment, positioning poles 32 are welded to both sides of the electric lifting rod 31 and to the top surface of the lifting base plate 30. The tops of the two positioning poles 32 extend upward to the outside of the U-shaped frame rod 21. Two connecting plates 19 are symmetrically installed on one inner wall of the high-temperature cooling box 7, the medium-temperature cooling box 8, the low-temperature cooling box 9, or the cleaning box 10. A tension roller 20 is rotatably installed between the two connecting plates 19, and the outer wall of the cable sheath 2 passes through the tension roller 20. The cable tension can be dynamically adjusted throughout the cooling process to prevent slack or overstretching caused by thermal expansion and contraction or traction fluctuations. The position of the tension roller 20 is adjustable to adapt to different wire diameters and speed requirements. Compared with the existing fixed tension system, this achieves straight cable routing, uniform sheath thickness, and no bamboo or necking defects, significantly improving product roundness and mechanical reliability. At the same time, the design of the tension roller 20 allows the cable to spend more time in the cooling box, improving the cooling effect.

[0034] Working principle: The cooling device used in the production of this communication cable features a multi-strand stranded core wire 1, consisting of a central tensile steel wire and multiple conductors (such as copper wire or optical fiber bundles) stranded around it. The stranding direction of the conductors is consistent with the extrusion direction of the subsequent sheath 2, and the stranding pitch is controlled at 10–15 times the conductor diameter to ensure structural stability and flexibility.

[0035] First, an insulating sleeve 3 is wrapped around the core wire 1 for electrical isolation. A gradient filling layer 4 is set outside the insulating sleeve 3. The material density of this layer gradually decreases from the inside to the outside, which helps to conduct heat evenly and buffer thermal stress. A fire-retardant sleeve 5 is then wrapped outside the gradient filling layer 4 to improve the flame-retardant safety performance of the cable. The outermost layer is a sheath 2 wrapped by an extruder. The sheath material is low-temperature resistant modified PVC or PE. If it is PVC, its formula includes high polymerization resin (1250-1350), composite plasticizer (DOTP / DOS), calcium-zinc stabilizer, spherical nano-active calcium, etc., to ensure that its low-temperature embrittlement temperature is ≤-48℃. If it is PE, it takes advantage of its own characteristic of maintaining good toughness at -78℃, without additional modification.

[0036] Sheath 2 is molten (approximately 160–200°C) covering the outer layer of the cable at the extruder head. At this time, the cable is in a high-temperature softened state and needs to be immediately introduced into the cooling system for shaping. The cable is introduced into the cooling device from the extruder outlet via the first conveyor shaft 16, and passes through the following four functional areas in sequence: Step 1: Initial slow cooling in the high-temperature zone cooling box 7. The cable enters the high-temperature zone cooling box 7 from the inlet / outlet 13. The water temperature inside the box is maintained at 80℃±5℃. The cable passes around the third transmission shaft 33 at the bottom to achieve full immersion and slow cooling, avoiding the concentration of shrinkage stress caused by sudden cooling of the outer layer. At the same time, the servo motor 27 drives the chassis 26 to rotate, driving the upper cross support 25 and cross cleaning brush 22 to actively rotate and brush the surface of the sheath 2 in the high-temperature softened state, removing residual impurities or oxides. After cleaning, the cable passes through a pair of oppositely arranged wiping cotton pads 23 (fixed on the fixed base plate 24), and is further dried and polished by clamping friction. The top of the box is equipped with a protective top cover 11, on which a magnetic regenerator 12 is installed, which can purify and regenerate the cooling medium (such as water containing magnetic particles) online, improving water quality stability. The anti-wear silicone gasket 14 at the outlet protects the cable from mechanical wear.

[0037] Step 2: Water cooling and shaping in the intermediate temperature zone cooling box 8. The cable is guided into the intermediate temperature zone cooling box 8 by the second transmission shaft 18. The box is filled with room temperature or temperature-controlled water (about 30℃±2℃). The sheath 2 is further solidified by immersion cooling. Multiple sets of second transmission shafts 18 and the bottom third transmission shaft 33 form an S-shaped cable routing path to extend the cooling time and ensure uniform temperature inside and outside the cross section. This stage mainly completes the shaping of the sheath structure and releases most of the thermal stress.

[0038] Step 3: Deep cryogenic adhesion control in the low-temperature cooling box 9. The cable enters the low-temperature cooling box 9, which is filled with liquid nitrogen. However, the actual operating temperature is maintained at -78℃±3℃ through vaporization temperature control. Liquid nitrogen has extremely high heat absorption efficiency during vaporization, which can quickly cool the surface of the sheath 2 to the target temperature in a very short time. Since the sheath material has been modified to have excellent low-temperature toughness (PVC ≥ -48℃ embrittlement point, PE is naturally resistant to low temperatures), it will not crack. The key function is to precisely control the interfacial crystallization behavior and shrinkage matching degree between the sheath 2 and the inner layer (fireproof and flame-retardant sheath 5 / gradient filler layer 4) through this deep cryogenic stage, so that the peel force is stabilized at 0.5-2N / mm, achieving a balance of "strong adhesion but easy peeling". The density gradient design of the gradient filler layer 4 plays a synergistic role in this stage, guiding the heat flow to dissipate evenly and preventing interfacial delamination.

[0039] Step 4: Tension adjustment. A connecting plate 19 is provided on the side wall of any cooling box, on which a tension roller 20 is rotatably installed. The cable passes around the tension roller 20. By adjusting its position, the tension of the cable during the cooling process can be controlled to prevent slack shaking or excessive stretching that could lead to eccentricity.

[0040] Step 5: Final cleaning of cleaning box 10. The cable enters cleaning box 10, which contains clean water to remove trace impurities or condensate that may have adhered during the cooling process. A two-stage wiping mechanism is installed at the outlet. Below: A cleaning cotton sleeve 28 is fitted around the second transmission shaft 18; Above: An electric lifting rod 31 is installed inside the U-shaped frame rod 21, and its lower end is connected to the lifting base plate 30 and the cleaning cotton block 29; The pressure is adjusted by the electric lifting rod 31, allowing the cleaning cotton pad 29 and the cleaning cotton sleeve 28 to form a controllable clamping force on the cable, achieving high-precision surface wiping. The positioning rod 32 ensures vertical stability during the lifting process, preventing displacement and damage to the cable. It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A communication cable, comprising a core wire and a sheath covering the outside of the core wire, characterized in that: The sheath is formed by a gradient temperature cooling process, which includes three stages: high-temperature cooling, medium-temperature cooling, and low-temperature cooling performed sequentially. The sheath material is a low-temperature resistant modified material. When polyvinyl chloride is used, the low-temperature embrittlement temperature of the polyvinyl chloride is not lower than -48°C. When polyethylene is used, the polyethylene still maintains good toughness at -78°C. The interfacial adhesion between the core wire and the sheath is optimized by gradient temperature control and remains uniform along the entire length of the cable. The peel force of the sheath is controlled within the range of 0.5-2 N / mm.

2. The communication cable according to claim 1, characterized in that: When the sheath material is polyvinyl chloride (PVC), the PVC material comprises, by weight, 100 parts PVC resin, 40-75 parts composite plasticizer, 0.4-1.6 parts composite lubricant, 15-25 parts composite flame retardant, 5-12 parts calcium-zinc stabilizer, 6-10 parts modified calcined clay, 8-12 parts vinyl acetate-propylene block copolymer, and 40-70 parts spherical nano-active calcium.

3. A communication cable according to claim 2, characterized in that: The degree of polymerization of the polyvinyl chloride resin is 1250-1350, the composite plasticizer includes a mixture of dioctyl terephthalate (DOTP), phthalate plasticizers and dioctyl sebacate (DOS), and the composite lubricant includes a mixture of high-melting-point oxidized polyethylene wax lubricant and stearic acid lubricant.

4. A communication cable according to claim 3, characterized in that: The core wire adopts a multi-strand stranded structure, which includes a central tensile steel wire and multiple conductors stranded around the central tensile steel wire; The stranding direction of the conductor is consistent with the extrusion direction of the sheath, and the stranding pitch of the conductor is 10-15 times the diameter of the conductor. A gradient filler layer is provided between the core wire and the sheath, and the material density of the gradient filler layer gradually decreases from the core wire side to the sheath side.

5. A cooling device for manufacturing communication cables, characterized in that, The system includes a high-temperature cooling box, a medium-temperature cooling box, a low-temperature cooling box, and a cleaning box arranged in sequence. The top of the high-temperature cooling box is equipped with a protective cover, and a magnetic regenerator is installed through the protective cover. The medium-temperature cooling box contains water for water cooling. The low-temperature cooling box contains liquid nitrogen. The cleaning box contains cleaning water for cleaning the outer wall of the cable sheath.

6. A cooling device for manufacturing communication cables according to claim 5, characterized in that: The top two sides of the high-temperature zone cooling box, the medium-temperature zone cooling box, the low-temperature zone cooling box, and the cleaning box are all provided with second conveyor shafts. Fixed ear plate seats are installed at the top edge of the high-temperature zone cooling box, the medium-temperature zone cooling box, the low-temperature zone cooling box, and the cleaning box. The second conveyor shaft is rotatably installed between two opposite fixed ear plate seats. The top of the side of the high-temperature zone cooling box facing away from the medium-temperature zone cooling box is symmetrically welded with ear plates. The first conveyor shaft is rotatably installed between two ear plates. The protective top cover has inlets and outlets on both sides, and each inlet and outlet has an anti-wear silicone gasket bonded to its inner wall.

7. A cooling device for manufacturing communication cables according to claim 6, characterized in that: The lower part of the inner cavity of the high-temperature zone cooling box, the medium-temperature zone cooling box, the low-temperature zone cooling box, and the cleaning box are all rotatably installed with a third transmission shaft. The cable sheath is conveyed from the first transmission shaft to the inlet and outlet at the top of the high-temperature zone cooling box, enters the high-temperature zone cooling box, is conveyed by the third transmission shaft in the high-temperature zone cooling box, and is pulled out from the inlet and outlet on the other side of the protective top cover. Then, it is sequentially conveyed by the remaining second transmission shafts and extends through the medium-temperature zone cooling box, the low-temperature zone cooling box, and the cleaning box.

8. A cooling device for manufacturing communication cables according to claim 7, characterized in that: A servo motor is embedded in the inner bottom wall of the high-temperature cooling box. The top output shaft of the servo motor is connected to a chassis. A cross support is fixed on the top surface of the chassis. A cross cleaning brush is fixed on the top surface of the cross support. When the servo motor drives the chassis to rotate, the cross cleaning brush actively cleans the outer wall of the cable during the transmission process. The inner wall of the high-temperature cooling box near the medium-temperature cooling box is also provided with two oppositely arranged wiping pads for wiping the cleaned cable, so that the two wiping pads hold the cable and the cable is transmitted through friction between the two wiping pads.

9. A cooling device for manufacturing communication cables according to claim 8, characterized in that: A cleaning cotton sleeve is fixedly fitted around the second transmission shaft on the side of the cleaning box away from the low-temperature cooling box. An inverted U-shaped frame rod is fixed above the cleaning cotton sleeve and above the two adjacent fixed ear plates. An electric lifting rod is longitudinally installed on the inner top wall of the U-shaped frame rod. A lifting base plate is fixed at the bottom lifting end of the electric lifting rod. A cleaning cotton block is fixed on the bottom surface of the lifting base plate. The outer wall of the cable sheath is clamped and rubbed between the cleaning cotton block and the cleaning cotton sleeve.

10. A cooling device for manufacturing communication cables according to claim 9, characterized in that: Positioning poles are welded to both sides of the electric lifting rod and to the top surface of the lifting base plate. The tops of the two positioning poles extend upward to the outside of the U-shaped frame. Two connecting plates are symmetrically installed on one inner wall of the high-temperature zone cooling box, medium-temperature zone cooling box, low-temperature zone cooling box, or cleaning box. A tensioning roller is rotatably installed between the two connecting plates. The outer wall of the cable sheath passes through the tensioning roller.

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