Methods for manufacturing flame-retardant cables and energy-saving cables

Abstract

This invention discloses a flame-retardant cable and its energy-saving manufacturing method, aiming to improve heat dissipation efficiency and reduce energy consumption. The flame-retardant cable, from the inside out, includes a conductor bundle, an insulating sheath, a filling layer, an isolation sheath, a steel strip layer, and an outer sheath, with added heat dissipation components including heat-conducting strips and tree-shaped heat dissipation forks. The insulating sheath or filling layer is attached to the pad portion of the heat-conducting strip, and the strip penetrates the isolation sheath to contact the steel strip layer; the tree-shaped heat dissipation forks are connected to the heat-conducting strips via hooks, and their surfaces are coated with a heat-conducting coating. The manufacturing method includes: installing heat-conducting strips with hot-melt adhesive support blocks to form a double-layer isolation sheath; piercing the sheath with spikes to expose the heat-conducting strips; flattening the exposed portion with a cooling sleeve; preheating the plastic granules with cooling hot air and assisting in melting the support blocks; optimizing air supply energy consumption by finding the minimum wind speed; and finally, water cooling reinforcement and installation of the steel strip layer and outer sheath. This invention enhances heat dissipation, achieves energy saving through heat recovery and process optimization, and ensures flame retardancy and stability.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and in particular to methods for preparing flame-retardant cables and energy-saving cables. Background Technology

[0002] Flame-retardant cables are special cables designed and manufactured using unique flame-retardant materials and structural processes. They effectively suppress flame spread, slow combustion, and reduce the release of toxic fumes during a fire. Their core characteristic lies in achieving "self-extinguishing" or "fire-retardant" effects through material modification or structural optimization. When the cable comes into contact with a flame, the flame-retardant layer prevents the flame from spreading to unburned areas through heat absorption, insulation, and the formation of a carbonized layer, thus avoiding the rapid spread of fire along the cable and buying valuable time for evacuation and firefighting.

[0003] From a materials perspective, the insulation and sheathing layers of flame-retardant cables are typically made of polymeric materials with added flame retardants (such as halogenated or halogen-free flame retardants), such as polyvinyl chloride (PVC) and cross-linked polyethylene (XLPE) that have undergone flame-retardant treatment. Among these, halogen-free flame-retardant cables release less smoke and have lower toxicity when burning, better meeting the high environmental and personnel protection requirements of modern fire safety. They are widely used in densely populated or environmentally sensitive locations such as high-rise buildings, subways, hospitals, and data centers.

[0004] The structural design of flame-retardant cables revolves around the core objectives of "fire resistance, heat insulation, and ensuring electrical performance," typically forming a multi-layered, synergistic composite structure from the inside out. The innermost layer is the conductor, often made of high-purity copper or aluminum to ensure good conductivity. The conductor surface may undergo annealing treatment to enhance flexibility and meet laying requirements. The conductor is then wrapped with an insulation layer, a key layer in the flame-retardant design. This insulation layer commonly uses flame-retardant modified polymer materials, such as flame-retardant polyvinyl chloride (PVC), cross-linked polyethylene (XLPE), or low-smoke halogen-free flame-retardant materials. This not only provides electrical insulation between the conductor and the external environment, but the added flame retardants (such as inorganic flame retardants like aluminum hydroxide and magnesium hydroxide, or halogenated organic flame retardants) can also inhibit combustion at high temperatures through endothermic decomposition and the formation of a barrier layer.

[0005] Outside the insulation layer, depending on the cable type and flame retardant rating requirements, a flame-retardant filler layer or wrapping layer may be installed. The filler layer often uses flame-retardant rope or tape to fill the gaps between the cable cores, making the cable structure more stable and further blocking the flame propagation path. The wrapping layer commonly uses high-temperature resistant materials such as fiberglass tape and mica tape. These materials have excellent heat insulation and flame-retardant properties, forming a hard carbonized layer in flames, delaying the transfer of heat to the internal insulation layer and conductor. For cables with high flame retardant ratings, a flame-retardant sheath is also installed on the outer layer, usually using a thicker flame-retardant material, such as halogen-free low-smoke flame-retardant polyolefin. This not only protects the internal structure from mechanical damage, but its own flame-retardant properties and low smoke and low toxicity during combustion effectively reduce the smoke hazard in a fire. In some special scenarios, flame-retardant cables may also have a metal armor layer (such as steel tape or steel wire armor). In addition to enhancing mechanical strength, the thermal conductivity and barrier properties of the metal layer can also help delay the spread of flames, forming a multi-layered flame-retardant protection system.

[0006] Existing flame-retardant cables still face several unresolved issues in practical applications, largely stemming from the challenge of balancing flame-retardant performance with other core properties. These issues primarily manifest as: limitations imposed by materials and structure on basic performance, insufficient heat dissipation, the conflict between environmental protection and safety performance, and limitations in cost and applicability.

[0007] Insufficient heat dissipation is a common problem. Flame-retardant materials themselves have low thermal conductivity. In addition, the multi-layer flame-retardant wrapping and armor layer design will significantly hinder heat transfer, causing the cable temperature to rise easily when operating under high load. This may not only shorten the service life, but also require reducing the current carrying capacity to ensure safety, which indirectly limits the power transmission efficiency. Summary of the Invention

[0008] Based on this, the present invention provides a flame-retardant cable and an energy-saving manufacturing method, aiming to enhance heat dissipation efficiency through structural innovation and reduce energy consumption through process optimization, thereby saving energy, while ensuring the flame-retardant performance and mechanical stability of the cable.

[0009] In one aspect, the present invention provides a flame-retardant cable comprising, from the inside out, a conductor bundle, an insulating sleeve, a filling layer, an isolation sleeve, a steel tape layer, and an outer sheath;

[0010] The insulating sleeve is fitted over the wire bundle, and multiple insulating sleeves are arranged in parallel, with the filling layer disposed between two adjacent insulating sleeves;

[0011] Multiple insulating sleeves and multiple filling layers are bundled together and fitted inside the insulating sleeve;

[0012] The steel strip layer is fitted over the isolation sleeve, and the outer sheath is fitted over the steel strip layer;

[0013] It also includes a heat dissipation assembly, which is mounted on the isolation sleeve and connected to the inner and outer sides of the isolation sleeve respectively;

[0014] The heat dissipation component includes heat-conducting strips and tree-shaped heat dissipation forks;

[0015] The heat-conducting strip includes a pad portion and a strip portion. The pad portion is flat and arc-shaped, with one side of it tightly attached to the inner wall of the isolation sleeve. One end of the strip portion is connected to the middle of the pad portion, and the strip portion is arc-shaped with a spike at the other end.

[0016] The strip penetrates the isolation sleeve and contacts the steel strip layer;

[0017] The middle part of the tree-shaped heat dissipation fork is connected to the strip part of the heat-conducting strip and installed inside the isolation sleeve.

[0018] Furthermore, the other side of the pad portion of the heat-conducting strip is in close contact with the insulating sleeve or the filling layer.

[0019] Furthermore, the tree-shaped heat dissipation fork includes a rod and a fork, one end of the rod is formed with a hook, and one end of the fork is fixedly connected to the other end of the rod.

[0020] The tree-shaped heat dissipation fork is assembled and connected to the strip portion of the heat-conducting strip via the hook.

[0021] Furthermore, the tree-shaped heat dissipation fork is made of flame-retardant PP material, and its surface is coated with a thermally conductive coating.

[0022] In another aspect, the present invention provides an energy-saving cable manufacturing method for producing a flame-retardant cable as described in any of the preceding claims, comprising the steps of:

[0023] S30. Install a support block on the strip of the heat-conducting strip. The support block is made of hot melt adhesive.

[0024] Apply adhesive to the pad of the heat-conducting strip, and attach the heat-conducting strip to the surface of the insulating sleeve or filling layer through the first clamp, so that the spikes of the heat-conducting strip are away from the pad.

[0025] S40. A first layer of sleeve is formed on the outside of multiple insulating sleeves and multiple filling layers bundled together. When the first layer of sleeve encounters a spike, the spike punctures the first layer of sleeve. At the same time, the support block is thermally melted and deformed in a high-temperature environment.

[0026] S50. The tree-shaped heat dissipation fork is hooked onto the strip of the heat-conducting strip by the second clamp, and the length direction of the tree-shaped heat dissipation fork is consistent with the length direction of the cable.

[0027] S60. A second layer of sleeve is formed outside the first layer of sleeve. At this time, after the second layer of sleeve encounters the spike, the second layer of sleeve is pierced, so that the spike of the heat-conducting strip is located outside the second layer of sleeve.

[0028] The thickness ratio of the first sleeve and the second sleeve is 6:4. They are extruded through the same extruder and then split to two die heads for separate forming. The flow ratio of the extruded material to the two die heads is 6:4.

[0029] S70. By squeezing the inner wall of the cooling sleeve, the portion of the heat-conducting strip located outside the second sleeve is flattened on the surface of the second sleeve; air is introduced into the cooling sleeve to accelerate the cooling of the first and second sleeves, and the heated plastic particles are preheated by the heated air.

[0030] Furthermore, the cooling sleeve includes two semi-circular rings with cavities formed inside. Connecting pipes are installed on both sides of the rings, one connecting pipe for connecting to a fan and the other connecting pipe for connecting to the feed end of the plastic granules.

[0031] A connecting post is installed on the outer wall of the collar, and the connecting post is connected to the drive mechanism;

[0032] Two collars are placed facing each other to form a ring, and two driving mechanisms drive their respective collars to make the two collars merge or separate.

[0033] One end of the inner wall of the collar has a ring surface with an oblique cross-section, so that the inner wall of the collar has an oblique surface and a;

[0034] The inner diameter of the collar is larger than the outer diameter of the second sleeve.

[0035] Furthermore, a predetermined proportion of the hot air obtained in step S70 is used to melt the support block in step S40.

[0036] The air introduced into the cooling sleeve enters in a turbulent manner.

[0037] Furthermore, step S70 also includes: finding the minimum wind speed at the heat peak and establishing a correlation between the minimum wind speed and the surface temperature of the second layer.

[0038] Furthermore, the minimum wind speed for finding the heat peak includes:

[0039] S791. Record the current surface temperature of the second layer of the casing;

[0040] S792. Increase the wind speed from 0 at predetermined increments every 5-10 minutes.

[0041] S793, Obtain the temperature of the plastic particles at each wind speed;

[0042] S794. Generate the correlation curve between wind speed and plastic particle temperature until the maximum wind speed is reached;

[0043] S795. Based on the correlation curve and the set threshold for the temperature increase of plastic particles, find the temperature value when the temperature increase of plastic particles is slow, and take it as the minimum temperature value; take the wind speed corresponding to the minimum temperature value as the minimum wind speed.

[0044] S796. Establish the relationship between the second layer and the corresponding minimum wind speed.

[0045] Furthermore, prior to step S30, the following step is also included:

[0046] S10. An insulating sleeve is formed on the surface of the wire harness;

[0047] S20. A filler layer is provided around the insulating sleeve;

[0048] Following step S70, the following step is also included:

[0049] S80. The first and second sleeves are cooled down by water cooling, which also makes the first and second sleeves fit together tightly.

[0050] S90, Install the steel strip layer and form an outer sheath outside the steel strip layer.

[0051] The beneficial effects of this invention are:

[0052] 1) Equipped with heat-conducting strips and tree-shaped heat dissipation forks, heat can be conducted from the filler layer or insulation sleeve to the steel strip layer more quickly, thus enabling heat to be conducted from the inner layer to the outer layer of the cable more quickly and accelerating the heat dissipation of the cable;

[0053] 2) When preparing the isolation sleeve, it is composed of a first layer and a second layer. First, the traditional single-layer preparation process is changed to a double-layer split forming and superposition process, which allows the spikes of the heat-conducting strip to pierce the double-layer structure and to place a tree-shaped heat dissipation difference between the double-layer structure. Second, the double-layer structure cools down one by one, which speeds up the forming speed of the isolation sleeve. Third, the double-layer structure and the single-layer structure use the same extruder and the same extrusion process parameters, which does not increase the load on the extruder.

[0054] 3) By using air cooling and a cooling sleeve, the cooling rate of the first and second sleeves can be accelerated, and the heat of the heated air can be recovered and utilized, thereby reducing the heating load of the extruder and achieving energy saving. In addition, the cooling sleeve also flattens the protruding part of the heat-conducting strip.

[0055] 4) By finding the minimum wind speed, the optimal solution for the energy consumption of the air supply volume can be achieved, thus achieving energy saving in air supply.

[0056] 5) A major difference from the existing technology is the setting of the support block, which not only supports the installation of the heat-conducting strip, but also allows it to be heat-melted at high temperature during the first layer of the sleeve after the heat-conducting strip is installed, without hindering the installation of the first and second layers of the sleeve.

[0057] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0058] Figure 1 This is a three-dimensional structural schematic diagram of an exemplary heat dissipation component of the present invention;

[0059] Figure 2 This is a schematic diagram of the cross-sectional structure of an exemplary flame-retardant cable of the present invention;

[0060] Figure 3 This is a front view illustrating the assembly relationship between the heat dissipation component and the support block, as exemplarily described in this invention.

[0061] Figure 4 This is a flowchart illustrating an exemplary energy-saving cable manufacturing method of the present invention;

[0062] Figure 5 This is a schematic diagram illustrating the relationship between the process flow of steps S30-S60 of the present invention and the extruder.

[0063] Figure 6 This is a schematic diagram showing the state after step S40 of the present invention is completed, as exemplarily described.

[0064] Figure 7 This is a schematic diagram showing the state after step S50 of the present invention is completed, as exemplarily described.

[0065] Figure 8 This is a schematic diagram showing the state after step S60 of the present invention is completed, as exemplarily described.

[0066] Figure 9 This is a schematic diagram showing the state after step S70 of the present invention is completed, as exemplarily described.

[0067] Figure 10 This is a schematic cross-sectional view of an exemplary cooling sleeve of the present invention;

[0068] Figure 11 This is a three-dimensional structural diagram of an exemplary tree-shaped heat dissipation fork of the present invention. Detailed Implementation

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0070] (a) The flame-retardant cable structure of the present invention.

[0071] The flame-retardant cable provided by this invention achieves synergistic optimization of flame retardancy and heat dissipation, and its structure is arranged from the inside out as follows:

[0072] Conductor harness 11: As the conductive core of the cable, it is made of high-purity copper or aluminum to ensure good conductivity. It can be set with single or multiple strands of conductors according to power transmission requirements.

[0073] Insulating sleeve: Sleeve over the conductor bundle 11, made of flame-retardant modified polymer material, to achieve electrical insulation between the conductor bundle 11 and the outside environment. Multiple insulating sleeves are arranged in parallel, providing a basis for the multi-core structure of the cable.

[0074] Filler layer 12: Located between two adjacent insulating sleeves, using materials such as flame-retardant rope or flame-retardant tape to fill the gaps between the insulating sleeves, making the cable structure more stable and also helping to block the spread of flames.

[0075] Isolation sleeve 30: It is composed of a first sleeve body 31 and a second sleeve body 32. It is sleeved on the bundle formed by multiple insulating sleeves and filling layers 12, and plays the role of isolating and protecting the internal structure, while providing a mounting carrier for heat dissipation components.

[0076] Steel strip layer 60: Sleeve over the isolation sleeve 30, made of high-strength steel strip, which not only enhances the mechanical strength of the cable and resists external mechanical damage, but also uses the thermal conductivity and barrier properties of metal to assist in heat dissipation and fire prevention.

[0077] Outer sheath 70: Sleeved over the steel strip layer 60, it is made of halogen-free, low-smoke, flame-retardant polyolefin and other materials, serving as the outermost layer of protection for the cable, further improving its flame-retardant performance and weather resistance.

[0078] Heat dissipation components: Installed on the isolation sleeve 30 and connected to the inner and outer sides of the isolation sleeve 30 respectively, it is the core structure for improving the heat dissipation efficiency of the cable, including heat conduction strip 20 and tree-shaped heat dissipation fork 40.

[0079] Heat-conducting strip 20: includes a pad portion 21 and a strip portion 22. The pad portion 21 is flat and arc-shaped, with one side tightly attached to the inner wall of the isolation sleeve 30 and the other side tightly attached to the insulating sleeve or filling layer 12, increasing the heat contact area; the strip portion 22 is arc-shaped, with one end connected to the middle of the pad portion and the other end forming a spike. The strip portion penetrates the isolation sleeve 30 and contacts the steel strip layer 60, realizing direct heat conduction from the inner layer to the outer layer.

[0080] Tree-shaped heat dissipation fork 40: Made of flame-retardant PP material with a thermally conductive coating, such as graphene thermally conductive coating, to enhance flame retardancy and thermal conductivity. It includes a rod and a fork. One end of the rod is bent into a hook, which is assembled and connected to the strip of the heat-conducting strip 20. The fork is fixedly connected to the other end of the rod, and its length direction is consistent with the length direction of the cable, which can increase the internal heat dissipation area and accelerate the transfer of heat to the heat-conducting strip 20.

[0081] The tree-shaped heat dissipation fork has an arc surface, and this arc surface is consistent with the arc shape of the surface of the first layer of the sleeve, so that the tree-shaped heat dissipation fork fits tightly with the first layer of the sleeve.

[0082] (ii) The method for preparing the energy-saving cable of the present invention.

[0083] This method is used to manufacture the aforementioned flame-retardant cables. Through process optimization, it achieves energy saving and high-efficiency production. The specific steps are as follows:

[0084] 1. Preliminary preparations (S10-S20).

[0085] S10: An insulating sleeve is formed on the surface of the wire harness 11 by an extrusion molding process to ensure that the insulating sleeve evenly wraps the wire harness 11 and meets the electrical insulation requirements.

[0086] S20: A filling layer 12 is provided in the gap between multiple insulating sleeves so that the insulating sleeves and the filling layer 12 are initially combined into an integral structure.

[0087] 2. Heat-conducting strip 20 installation (S30).

[0088] A support block made of hot melt adhesive is installed on the strip of the heat-conducting strip 20. The support block is used to temporarily fix the position of the heat-conducting strip 20 in subsequent processes.

[0089] Apply high-temperature resistant adhesive to the pad of the heat-conducting strip 20, and use the first clamp to precisely attach the heat-conducting strip 20 to the surface of the insulating sleeve or filling layer 12, ensuring that the pad is tightly attached and that the barbs of the heat-conducting strip 20 are away from the pad, in preparation for piercing the sleeve body later.

[0090] The first gripper operates on at least two principles: one is that the first gripper uses a suction cup to adsorb the pad portion of the heat-conducting strip 20, attaches the heat-conducting strip 20 to the insulating sleeve or filling layer 12, and then releases the heat-conducting strip 20; the other is that the first gripper holds the strip portion of the heat-conducting strip 20 by clamping, attaches the heat-conducting strip 20 to the insulating sleeve or filling layer 12, and then releases the heat-conducting strip 20.

[0091] Alternatively, in a configuration where one gripper holds one heat-conducting strip 20, two opposing first grippers can be used to attach the two heat-conducting strips 20 to the surface of the insulating sleeve or filler layer 12 from two opposing directions. Three, four, or other equal numbers of first grippers can also be used to transport the heat-conducting strips 20 from multiple directions.

[0092] The structure of the first gripper will not be described or shown in detail. It can be a robotic arm, a cylinder mechanism with a gripper, or even a multi-axis robot.

[0093] In other options, the following approach can also be adopted in the preliminary preparation (S10-S20).

[0094] S10. Insulation Sleeve Molding: Flame-retardant modified plastic granules, such as flame-retardant PVC or XLPE, are heated and melted using a precision extruder, and then evenly coated onto the surface of the wire harness 11 through the die head. During the extrusion process, the die head temperature is strictly controlled at 180-220℃ and the traction speed at 5-10m / min to ensure that the insulation sleeve has a uniform thickness with an error ≤0.1mm, and that it fits tightly to the wire harness 11 without air bubbles. The molded insulation sleeve needs to undergo preliminary water cooling at a water temperature of 20-30℃ to set its shape and prevent deformation in subsequent processes.

[0095] S20, Filler Layer 12 Setup: An automatic cable feeding machine is used to evenly wind flame-retardant filler rope, such as fiberglass flame-retardant rope, into the gaps between multiple parallel insulating sleeves. The filling density is controlled at over 85% to ensure the stability of the cable bundle structure. During the filling process, the tension of the filler rope is adjusted by 5-10N using a tension controller to avoid either being too loose, which would lead to a loose structure, or too tight, which would compress the insulating sleeves.

[0096] like Figures 6 to 9 As shown.

[0097] 3. The first layer of the sleeve 31 is formed (S40).

[0098] Outside of the bundle of multiple insulating sleeves and filler layers 12, a first sleeve 31 is formed by an extrusion process. At this time, the first sleeve 31 is punctured after contacting the spikes of the heat-conducting strip 20, allowing the strip portion to penetrate the first sleeve 31; at the same time, the high temperature environment of the extrusion process causes the support block to be thermally melted and deformed, preventing it from affecting the adhesion between the sleeve and the heat-conducting strip 20.

[0099] The melting point of the hot melt adhesive is lower than the surface temperature of the first layer 31.

[0100] 4. Tree-shaped heat dissipation fork 40 installation (S50).

[0101] The second gripper hooks the tree-shaped heat dissipation fork 40 onto the strip of the heat-conducting strip 20, ensuring that the length direction of the tree-shaped heat dissipation fork 40 is consistent with the length direction of the cable, thereby achieving a stable connection between the heat dissipation fork and the heat-conducting strip 20 and expanding the internal heat dissipation range.

[0102] The second gripper assembles the tree-shaped heat dissipation fork 40 and the heat-conducting strip 20 in two ways: one is to align the hook of the tree-shaped heat dissipation fork 40 with the strip of the heat-conducting strip 20, and directly hook the hook onto the heat-conducting strip 20; the other is to align the notch of the hook of the tree-shaped heat dissipation fork 40 with the heat-conducting strip 20, and then move the relative position of the hook and the heat-conducting strip 20 to hook the hook onto the heat-conducting strip 20.

[0103] The structure of the second gripper will not be described in detail or shown in the accompanying diagram; it can be a robotic arm or a multi-joint robot.

[0104] 5. The second layer of the sleeve is formed (S60).

[0105] See Figure 5 The process flow diagram and structural principle are shown.

[0106] A second sleeve 32 is formed outside the first sleeve 31 by an extrusion process. The second sleeve 32 is punctured after contacting the spikes, so that the spikes of the heat-conducting strip 20 are located outside the second sleeve 32, that is, outside the isolation sleeve 30.

[0107] The thickness ratio of the first sleeve 31 to the second sleeve 32 is 6:4. After being extruded by the same extruder, the flow is split to two die heads for separate forming. The flow ratio of the extruder to the two die heads is 6:4, which ensures precise control of the thickness of the double sleeve and eliminates the need for additional equipment, thus reducing energy consumption.

[0108] The high-temperature liquid phase from the extruder outlet splits into two streams, one of which flows to one die head and the other to the other die head. The cross-sectional area ratio of the pipes flowing to the two die heads is 6:4. The flow rate to the die head forming the first layer of sleeve 31 is larger, accounting for 60% of the total flow, while the flow rate to the die head forming the second layer of sleeve 32 is smaller, accounting for 40% of the total flow.

[0109] See again Figure 5 And on Figure 5The high-temperature liquid phase flowing out of the extruder is divided into two streams. One stream enters one die head and forms the first layer of the sleeve in process B2, while the other stream enters another die head and forms the second layer of the sleeve in process B4. The heat-conducting strip is installed in process B1, and the tree-shaped heat dissipation fork is installed in process B3.

[0110] 6. Cooling and heat recovery (S70).

[0111] The heat-conducting strip 20 located outside the second layer sleeve 32 is pressed flat on the surface of the second layer sleeve 32 by the squeezing action of the inner wall of the cooling sleeve 50, so that the heat-conducting strip 20 and the isolation sleeve 30 are tightly attached to each other, thereby improving the heat dissipation efficiency.

[0112] The cooling sleeve 50 consists of two semi-circular rings, with a cavity formed inside each ring. Connecting pipes 51 are installed on both sides: one connecting pipe 51 is used to connect to a fan for air supply; the other connecting pipe 51 is used to connect to the plastic granule feed end for heat recovery.

[0113] There are at least two ways to heat plastic granules with hot air. One way is to heat the plastic granules directly with hot air. In this way, a filter is installed on the pipeline to remove water and impurities. The other way is to heat the plastic granules indirectly through the outer wall of the hopper with hot air, so that the temperature of the plastic granules in the hopper increases.

[0114] The outer wall of the collar is connected to the drive mechanism via a connecting column, which can control the merging or separation of the two collars to facilitate cable entry and exit; one end of the inner wall of the collar forms a sloping ring surface, forming a sloping structure to help flatten the heat-conducting strip 20; the inner diameter of the collar is larger than the outer diameter of the second layer of the sleeve 32 to ensure that the cable passes through smoothly.

[0115] Turbulent air is introduced into the cooling sleeve 50 to accelerate the cooling of the first sleeve 31 and the second sleeve 32. The air absorbs heat from the sleeves and its temperature rises. This heated air is then transported to the plastic granule feed end to preheat the plastic granules, reducing the extruder's heating energy consumption. Simultaneously, a predetermined proportion of the hot air is used for melting the support block in step S40, further realizing the secondary utilization of heat.

[0116] To achieve energy-saving air supply, it is necessary to find the minimum wind speed at the peak heat level: record the current surface temperature of the second layer 32; increase the wind speed from 0 at predetermined increments every 5-10 minutes; obtain the temperature of the plastic particles at each wind speed, and generate a wind speed-plastic particle temperature correlation curve up to the maximum wind speed; based on the curve, using the threshold value set for the increase in plastic particle temperature as the standard, find the minimum temperature value when the temperature increase is gradual, and the corresponding wind speed is the minimum wind speed; establish the correlation between the second layer 32 and the minimum wind speed to achieve optimal energy consumption control of the air supply.

[0117] The relationship between wind speed and temperature is not linear. Instead, as the wind speed increases, the temperature of the plastic granules increases, resulting in a rapid rise in temperature followed by a gradual leveling off.

[0118] As wind speed increases, the boundary layer thickness initially decreases rapidly, transitioning from laminar to turbulent flow at low wind speeds. Subsequently, the rate of decrease slows down, leading to the turbulent flow phase at high wind speeds. This nonlinear thickness variation results in inconsistent rates of thermal resistance reduction: at low wind speeds, thermal resistance decreases rapidly, and surface temperature drops significantly; at high wind speeds, thermal resistance decreases slowly, and surface temperature decreases more gradually.

[0119] If the wind speed is too high, the boundary layer thickness is already close to its minimum. If the wind speed is further increased, the boundary layer thickness changes very little, the thermal resistance remains almost unchanged, the heat exchange growth stagnates, and the surface temperature no longer decreases significantly, entering the "saturation zone".

[0120] Therefore, the relationship between wind speed and the heat generated by plastic particles is non-linear, and it exhibits a state of transition from steep slope to gentle slope.

[0121] In addition, in step S70, the cooling sleeve also has the effect of flattening the first layer sleeve, the tree-shaped heat dissipation fork, and the second layer sleeve as a whole, thereby preventing the second layer sleeve from bulging at the position of the tree-shaped heat dissipation fork.

[0122] 7. Subsequent processing (S80-S90).

[0123] S80: The first layer 31 and the second layer 32 are cooled and cooled by water cooling. At the same time, the water pressure is used to make the two layers of the sleeve fit together and tighten, thereby improving the structural stability of the isolation sleeve 30.

[0124] S90: A steel strip layer 60 is installed outside the isolation sleeve 30 and fixed by a winding or sleeve process; then an outer sheath 70 is formed outside the steel strip layer 60 by an extrusion process, completing the preparation of the entire flame-retardant cable.

[0125] right Figures 6-9 Please provide an explanation.

[0126] exist Figure 6 In the process, the bundled wires, insulating sleeves, and filling layers, which were prepared in the early stage, are bundled together to form a bundle structure A. After the heat-conducting strip 20 is attached to the bundle structure A, the first layer of the sleeve is formed by a machine head. That is, the state after step S40 is completed.

[0127] exist Figure 7 The diagram shows the state after step S50 is completed.

[0128] exist Figure 8 The image shows the state after step S60 is completed.

[0129] exist Figure 9The image shows the state after step S70 is completed, with one heat-conducting strip flattened and the other heat-conducting strip awaiting processing.

[0130] Some beneficial effects of the present invention:

[0131] Significantly improved heat dissipation efficiency: Through the coordinated design of the heat-conducting strip 20 and the tree-shaped heat dissipation fork 40, the heat-conducting strip 20 directly connects the inner layer (insulation sleeve, filling layer 12) and the outer layer (steel strip layer 60) of the cable, realizing rapid heat conduction; the tree-shaped heat dissipation fork 40 expands the internal heat dissipation area, accelerates the accumulation of heat in the heat-conducting strip 20, effectively solves the problem of insufficient heat dissipation caused by materials and structure in traditional flame-retardant cables, extends the service life of the cable, and improves current carrying capacity and power transmission efficiency.

[0132] The process boasts outstanding energy-saving performance: It adopts a split forming process with a double-layer sleeve (first layer sleeve 31 + second layer sleeve 32), and controls the thickness through the same extruder, eliminating the need for additional equipment load; during the cooling process, the heated air preheats the plastic particles and assists in melting the support block, achieving efficient heat recovery; by controlling the minimum wind speed, the energy consumption of the air supply is optimized, significantly reducing energy consumption in the production process.

[0133] Structural stability and flame retardancy are guaranteed: the filler layer 12 ensures the stability of the cable structure, the double-layer structure of the isolation sleeve 30, the steel strip layer 60, and the outer sheath 70 form multiple protections and improve mechanical strength; the tree-shaped heat dissipation fork 40 is made of flame-retardant PP material and coated with a thermally conductive coating, and the heat-conducting strip 20 is tightly attached to the sleeve body, which enhances heat dissipation without affecting the overall flame retardant performance of the cable and meets fire safety requirements.

[0134] Production efficiency optimization: The support block provides temporary fixation for the heat-conducting strip 20, and subsequent high-temperature automatic heat melting does not affect the forming of the sleeve; the integrated extrusion and cooling design of the cooling sleeve 50 simultaneously flattens the heat-conducting strip 20 and cools the sleeve, simplifying the production process and improving production efficiency.

[0135] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A flame-retardant cable, characterized in that: It includes, from the inside out, the conductor bundle, insulation sleeve, filling layer, isolation sleeve, steel strip layer, and outer sheath; The insulating sleeve is fitted over the wire bundle, and multiple insulating sleeves are arranged in parallel, with the filling layer disposed between two adjacent insulating sleeves; Multiple insulating sleeves and multiple filling layers are bundled together and fitted inside the insulating sleeve; The steel strip layer is fitted over the isolation sleeve, and the outer sheath is fitted over the steel strip layer; It also includes a heat dissipation assembly, which is mounted on the isolation sleeve and connected to the inner and outer sides of the isolation sleeve respectively; The heat dissipation component includes heat-conducting strips and tree-shaped heat dissipation forks; The heat-conducting strip includes a pad portion and a strip portion. The pad portion is flat and arc-shaped, with one side of it tightly attached to the inner wall of the isolation sleeve. One end of the strip portion is connected to the middle of the pad portion, and the strip portion is arc-shaped with a spike at the other end. The strip penetrates the isolation sleeve and contacts the steel strip layer; The middle part of the tree-shaped heat dissipation fork is connected to the strip part of the heat-conducting strip and installed inside the isolation sleeve.

2. The flame-retardant cable according to claim 1, characterized in that: The other side of the pad portion of the heat-conducting strip is in close contact with the insulating sleeve or the filling layer.

3. The flame-retardant cable according to claim 2, characterized in that: The tree-shaped heat dissipation fork includes a rod and a fork, one end of the rod is formed with a hook, and one end of the fork is fixedly connected to the other end of the rod. The tree-shaped heat dissipation fork is assembled and connected to the strip portion of the heat-conducting strip via the hook.

4. The flame-retardant cable according to claim 3, characterized in that: The tree-shaped heat dissipation fork is made of flame-retardant PP material, and its surface is coated with a thermally conductive coating.

5. A method for manufacturing an energy-saving cable, characterized in that, For manufacturing a flame-retardant cable as described in any one of claims 1-4, the steps include: S30. Install a support block on the strip of the heat-conducting strip. The support block is made of hot melt adhesive. Apply adhesive to the pad of the heat-conducting strip, and attach the heat-conducting strip to the surface of the insulating sleeve or filling layer through the first clamp, so that the spikes of the heat-conducting strip are away from the pad. S40. A first layer of sleeve is formed on the outside of multiple insulating sleeves and multiple filling layers bundled together. When the first layer of sleeve encounters a spike, the spike punctures the first layer of sleeve. At the same time, the support block is thermally melted and deformed in a high-temperature environment. S50. The tree-shaped heat dissipation fork is hooked onto the strip of the heat-conducting strip by the second clamp, and the length direction of the tree-shaped heat dissipation fork is consistent with the length direction of the cable. S60. A second layer of sleeve is formed outside the first layer of sleeve. At this time, after the second layer of sleeve encounters the spike, the second layer of sleeve is pierced, so that the spike of the heat-conducting strip is located outside the second layer of sleeve. The thickness ratio of the first sleeve and the second sleeve is 6:

4. They are extruded through the same extruder and then split to two die heads for separate forming. The flow ratio of the extruded material to the two die heads is 6:

4. S70. By squeezing the inner wall of the cooling sleeve, the portion of the heat-conducting strip located outside the second sleeve is flattened on the surface of the second sleeve; air is introduced into the cooling sleeve to accelerate the cooling of the first and second sleeves, and the heated air is used to preheat the plastic particles.

6. The method for manufacturing an energy-saving cable according to claim 5, characterized in that, The cooling sleeve includes two semi-circular rings with cavities inside. Connecting pipes are installed on both sides of the rings, one connecting pipe for connecting to a fan and the other connecting pipe for connecting to the feed end of the plastic granules. A connecting post is installed on the outer wall of the collar, and the connecting post is connected to the drive mechanism; Two collars are placed facing each other to form a ring, and two driving mechanisms drive their respective collars to make the two collars merge or separate. One end of the inner wall of the collar has a ring surface with an oblique cross-section, so that the inner wall of the collar has an oblique surface and a; The inner diameter of the collar is larger than the outer diameter of the second sleeve.

7. The method for manufacturing an energy-saving cable according to claim 6, characterized in that, The predetermined proportion of the hot air obtained in step S70 is used to melt the support block in step S40. The air introduced into the cooling sleeve enters in a turbulent manner.

8. The method for manufacturing an energy-saving cable according to claim 6, characterized in that, Step S70 further includes: finding the minimum wind speed at the heat peak and establishing a correlation between the minimum wind speed and the surface temperature of the second layer of the casing.

9. The method for manufacturing an energy-saving cable according to claim 8, characterized in that, The minimum wind speed required to locate the heat peak includes: S791. Record the current surface temperature of the second layer of the casing; S792. Increase the wind speed from 0 at predetermined increments every 5-10 minutes. S793, Obtain the temperature of the plastic particles at each wind speed; S794. Generate the correlation curve between wind speed and plastic particle temperature until the maximum wind speed is reached; S795. Based on the correlation curve and the set threshold for the temperature increase of plastic particles, find the temperature value when the temperature increase of plastic particles is slow, and take it as the minimum temperature value; take the wind speed corresponding to the minimum temperature value as the minimum wind speed. S796. Establish the relationship between the second layer and the corresponding minimum wind speed.

10. The method for manufacturing an energy-saving cable according to any one of claims 6-9, characterized in that, Before step S30, the following steps are also included: S10. An insulating sleeve is formed on the surface of the wire harness; S20. A filler layer is provided around the insulating sleeve; Following step S70, the following step is also included: S80. The first and second sleeves are cooled down by water cooling, which also makes the first and second sleeves fit together tightly. S90, Install the steel strip layer and form an outer sheath outside the steel strip layer.

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