One-step forming production process for double cable sheaths

Abstract

The invention relates to a cable double-sheath one-time forming production process which comprises the steps of S1, coloring, S2, plastic coating, S3, cabling and S4, the S4 is an inner sheath and outer sheath one-time forming process, and the inner sheath and outer sheath one-time forming integrates a plurality of key processes. The problems that in a traditional production mode, a large amount of time is consumed in intermediate links such as carrying, repositioning and production line adjustment which are caused by respective manufacturing of an inner protection and an outer protection, a one-time forming process enables the procedures to be continuously carried out, the production period is greatly shortened, and in the one-time forming process, due to the fact that the procedures are tightly connected, the production efficiency is greatly improved are solved. The equipment can continuously run, the frequent adjustment and waiting time of the equipment is shortened, in the one-time forming process, the equipment can continuously complete a plurality of procedures after parameters are set, the non-productive time loss is reduced, and the utilization rate and the overall production efficiency of the equipment are improved.

Description

Technical Field

[0001] The invention relates to the field of cable manufacturing technology, in particular to a one-time molding production process for cable double sheaths. Background Art

[0002] Cable manufacturing generally includes conductor processing (such as wire drawing and twisting of metal conductors such as copper and aluminum), insulation layer extrusion (wrapping insulating materials such as polyvinyl chloride and cross-linked polyethylene around the conductor through an extruder), cable core twisting (twisting multiple insulated cores together according to certain rules), and sheath processing. The entire manufacturing process requires strict control of parameters such as material quality, processing temperature, speed, etc. to ensure that the performance of the cable meets the requirements.

[0003] Among them, the cable sheath processing mainly adopts the extrusion process. The extruder heats and melts the solid sheath material, and through the push of the screw, the molten material is evenly wrapped around the cable core. During the extrusion process, it is necessary to control the temperature of the extruder, the screw speed and the pulling speed and other parameters. Too high temperature may cause the material to decompose, and too low temperature will cause poor material fluidity and cannot be extruded evenly; the screw speed affects the extrusion amount of the material, and the pulling speed determines the thickness of the sheath.

[0004] The separate processing of the sheath requires two independent sheath processing steps. After the first sheath processing is completed, the semi-finished cable needs to be transferred to the production equipment of the next process. This transfer process will consume extra time, including the handling of the cable, re-debugging of the equipment, etc., making the entire production process lengthy and extending the production cycle. In addition, two independent production lines are processed separately, which means that each cable needs to complete the sheath processing on two production lines in turn, which will lead to a decrease in the overall utilization of the equipment. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a one-step molding production process for double-sheath cables.

[0006] The present invention provides a cable double sheath one-step molding production process using the following technical solutions:

[0007] A one-step molding production process for double cable sheaths includes S1: coloring process, S2: plastic sheathing process, S3: cabling process, S4: sheathing process. The S4: sheathing process is a one-step molding process for inner and outer sheaths. The specific steps are as follows:

[0008] S40, cable core pay-off;

[0009] S41, cable paste filling, injecting the cable paste into the gap of the cable core, the cable paste is made of vaseline, paraffin, antioxidants, preservatives and other additives, and the cable paste is smoothly introduced into the gap of the cable core through a pressure filling device;

[0010] S42, longitudinal wrapping process A1, using metal strips or plastic film strips to wrap longitudinally along the cable core axis;

[0011] S43, extrusion process B1, the extruder extrude a first layer of sheath material on the cable core structure, wherein the first layer of sheath material is polyethylene or polyvinyl chloride;

[0012] S44, traction cooling C1, the traction machine pulls the extruded cable core at a uniform speed, and drives the cable core to move by friction through the traction wheel with rubber pad;

[0013] S45, inner sheath oil filling, through the special oil filling equipment, the oil is injected into the space between the inner sheath and the cable core at a pressure of about 0.2-0.4MPa;

[0014] S46, longitudinal wrapping process A2, in which a steel belt or a plastic belt with good oil resistance is used;

[0015] S47, extrusion process B2, the thickness of the sheath extruded by the extrusion process B2 is thicker than that of B1;

[0016] S48, traction cooling C2, the traction machine continues to pull the cable through the cooling device at a constant speed;

[0017] S49, reel in the line.

[0018] Optionally, in S41, the filling pressure is 0.1-0.3MPa, and the filling amount accounts for 75%-85% of the cable core gap volume; in S42, if it is an aluminum tape longitudinal wrap, the width of the aluminum tape is selected according to the cable core circumference and the longitudinal wrap overlap requirements, and the overlap width is 5-10mm to form a continuous and sealed wrapping layer, and the thickness of the aluminum tape is 0.2-0.5mm; in S43, the temperature of the extruder feeding section is 140-160°C, the temperature of the compression section is 160-180°C, and the temperature of the metering section is 180-200°C.

[0019] Optionally, in the S46 and longitudinal wrapping process A2, the overlap width is between 8-12 mm, the thickness of the steel belt is within the range of 0.5-1.0 mm, and the plastic belt used in A2 is a tetrafluoroethylene (PTFE) belt that will not swell or deteriorate in performance in an oil environment or a specially formulated polyethylene (PE) belt.

[0020] Optionally, the thickness of the sheath extruded by B1 is between 1.5-2.5 mm, and the thickness of the sheath extruded by B2 is between 2.0-3.0 mm.

[0021] Optionally, in the S44 and traction cooling C1, the traction machine is provided with tension feedback and adjustment functions to monitor and automatically adjust the cable core traction tension in real time. The cooling methods include water cooling, air cooling or a combination of the two. During water cooling, the water temperature of the water cooling tank is controlled at 10-30°C, and the water flow rate ensures that the heat of the sheath is taken away, so that the sheath is quickly cooled and shaped; during air cooling, the fan provides cold air blowing cooling with a wind speed of 2-10 m / s.

[0022] Optionally, in the S48 and traction cooling C2 processes, the specific structure and production speed of the water-cooling tank water temperature cable are between 10-30°C, and the air cooling wind speed is in the range of 2-10 m / s.

[0023] In summary, the present invention includes at least one of the following beneficial technical effects:

[0024] 1. The one-step molding of inner and outer guards integrates multiple key processes together, avoiding the intermediate links caused by the separate production of inner and outer guards in traditional production methods, such as handling, repositioning and adjustment of production lines, which will consume a lot of time. The one-step molding process allows these processes to be carried out continuously, greatly shortening the production cycle. In the one-step molding process, since the processes are closely connected, the equipment can run continuously, reducing the time for frequent adjustment and waiting of the equipment. In the one-step molding process, the equipment can complete multiple processes continuously after setting the parameters, reducing these non-productive time losses and improving the utilization rate of the equipment and the overall production efficiency;

[0025] 2. Through the one-step molding process, the inner and outer sheaths are more closely integrated with each other and with the internal structures such as the cable core. For example, in the process of longitudinal wrapping A2 and extrusion process B2, they can better match the structure of the inner sheath after oil filling and the first layer of sheath formed by extrusion process B1. During extrusion process B2, the mold size can be accurately adjusted according to the actual outer diameter of the cable after extrusion process B1 to ensure that the total thickness of the two layers of sheaths and the overall outer diameter of the cable meet the design requirements, thereby improving the consistency of the cable size accuracy;

[0026] 3. The one-time molding process of inner and outer guards merges two originally separate production lines into a whole, reducing the repeated investment in equipment. There is no need to set up independent extruders, longitudinal wrapping machines and other equipment for the inner and outer guards respectively, which reduces the equipment procurement cost. At the same time, due to the integration of processes, the floor space of the production line is also reduced accordingly, saving the cost of renting or building a factory. Compared with traditional processes, enterprises can use less equipment and site investment to achieve the same or even higher production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of the one-step forming process of the inner and outer guards. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The embodiment of the invention discloses a one-step molding production process for double-sheaths of cables.

[0030] A one-step molding production process for cable double sheaths includes S1: coloring process, S2 sheathing process, S3 cabling process, S4 sheathing process, S4 sheathing process is a one-step molding process for inner and outer sheaths, and the specific steps are as follows:

[0031] S40, cable core pay-off, the starting step of the process, provides a stable supply of cable cores for subsequent operations. A pay-off stand is used to place the cable core reel. The pay-off stand has an adjustable tension control device. Appropriate tension can ensure that the cable core is paid out smoothly to avoid entanglement caused by loose cable core or damage to the cable core due to excessive tension. At the same time, the speed of the pay-off stand is synchronized with the speed of the production line to ensure that the cable core is uniformly and uninterruptedly supplied to the next process;

[0032] S41, cable paste filling, inject cable paste into the gap of cable core. Cable paste is made of vaseline, paraffin wax, antioxidants, preservatives and other additives. Through pressure filling equipment, the cable paste can smoothly enter the gap of cable core. The filling pressure is 0.1-0.3MPa. This pressure range allows the cable paste to smoothly enter the gap of cable core without squeezing the cable core due to excessive pressure. The filling amount is determined according to the structure and size of the cable core. It is precisely controlled by calculating the porosity of the cable core and other parameters to fill the internal gap of the cable core without overflowing. It can enhance the moisture resistance, lubrication and integrity of the cable core. The filling amount generally accounts for 75%-85% of the volume of the cable core gap;

[0033] S42, longitudinal wrapping process A1, using metal strips or plastic film strips, longitudinally wrapping along the cable core axis. If it is aluminum strip longitudinal wrapping, the width of the aluminum strip is selected according to the cable core circumference and the longitudinal wrapping overlap requirements. The overlap width is 5-10mm to form a continuous and sealed wrapping layer. The thickness of the aluminum strip is 0.2-0.5mm. The longitudinal wrapping equipment uses rollers and guide devices to accurately wrap the strip longitudinally. For metal strips, welding may be used, and for plastic strips, bonding may be used to process the interface to ensure the integrity and sealing of the wrapping layer, providing preliminary protection for subsequent processes;

[0034] S43, extrusion process B1, the extruder extrude the first layer of sheath material on the cable core structure, the first layer of sheath material is polyethylene or polyvinyl chloride, the extruder feeding section temperature is 140-160°C, the compression section temperature is 160-180°C, and the metering section temperature is 180-200°C, to ensure uniform and stable extrusion of the material and provide preliminary insulation and protection;

[0035] S44, traction cooling C1, the traction machine pulls the extruded cable core at a uniform speed, so that the cable core can pass through the subsequent process stably at the predetermined production speed and direction. The traction machine drives the cable core to move by friction through a traction wheel with a rubber pad. The traction wheel speed is accurately adjusted, and the line speed matches the speed of the previous process. The error is controlled within ±5%, ensuring that the cable core is not piled up, stuck or over-stretched. At the same time, the traction machine has tension feedback and adjustment functions, real-time monitoring and automatic adjustment of the cable core traction tension. The cooling methods include water cooling, air cooling or a combination of the two. When water cooling, the water temperature of the water cooling tank is controlled at 10-30℃, and the water flow speed ensures that the heat of the sheath is taken away, so that the sheath is quickly cooled and shaped; when air cooling, the fan provides cold air blowing cooling with a wind speed of 2-10 m / s to ensure uniform cooling of the cable and avoid defects such as sheath deformation, bubbles or cracks;

[0036] S45, inner sheath oil filling, inject special filling oil into the cable that has completed the first layer of sheath. The filling oil is mainly used to improve the moisture resistance, insulation performance and thermal conductivity of the cable. The type of filling oil is selected according to the cable use and performance requirements. For example, high-voltage oil-filled cables often use mineral oil or synthetic oil with low viscosity, high insulation and good chemical stability. The oil filling process uses special oil filling equipment to inject oil into the space between the inside of the sheath and the cable core at a pressure of 0.2-0.4MPa to ensure that the internal space is fully filled but not over-filled to cause abnormal pressure, so as to maintain a good oil filling state inside the cable;

[0037] S46, longitudinal wrapping process A2, similar to the first longitudinal wrapping process, also uses metal strips or plastic strips for longitudinal wrapping, but requires thicker steel strips to enhance mechanical strength. Parameters such as steel strip width and overlap width are adjusted according to the outer diameter of the cable. The overlap width is between 8-12mm, and the steel strip thickness is within the range of 0.5-1.0mm;

[0038] S47, extrusion process B2. The thickness of the sheath extruded by extrusion process B2 is thicker than that of B1. Extrusion process B1 is mainly used to form the first layer of cable sheath. The material is usually a basic high molecular polymer, such as polyethylene (PE) or polyvinyl chloride (PVC). These materials themselves have basic insulation and protective properties. The formula is relatively simple. It is mainly to provide preliminary protection to prevent external factors from directly affecting the cable core. When ordinary PE materials are used for B1 extrusion, only a small amount of antioxidants are added to prevent the material from aging due to oxidation during processing and use. Extrusion process B2 is to further strengthen the protective function of the cable on the basis of the first layer of sheath. The material selection may still be polymers such as PE or PVC, but various functional additives will be added. In order to adapt to the outdoor environment, anti-ultraviolet agents will be added to prevent the sheath from aging and becoming brittle under long-term sunlight; in occasions with fire protection requirements, flame retardants will be added to make the sheath have flame retardant properties, such as adding flame retardants such as aluminum hydroxide to improve the fire safety of the cable;

[0039] S48, traction cooling C2, the traction machine continues to pull the cable through the cooling device at a uniform speed, the water temperature of the water cooling tank is between 10-30℃, and the air cooling wind speed is in the range of 2-10 m / s;

[0040] S49, Reeling: The cables that have completed all the processes are neatly and orderly reeled and stored by the reeling machine. The reeling machine has an adjustable tension control system. The reeling tension is generally controlled between 0.03-0.06MPa, depending on factors such as cable thickness, material and reeling speed, to avoid cable damage or looseness. The reeling speed matches the speed of the traction process to ensure a smooth and efficient reeling process. The reeling machine can also automatically complete the reeling according to preset parameters such as length or weight, which is convenient for packaging, transportation and use.

[0041] The principle of the present invention is: the one-time molding of the inner and outer guards integrates multiple key processes together, avoiding the intermediate links brought about by the separate production of the inner and outer guards in the traditional production method, such as transportation, repositioning and adjustment of the production line, which will consume a lot of time, and the one-time molding process enables these processes to be carried out continuously, greatly shortening the production cycle. In the one-time molding process, since the processes are closely connected, the equipment can run continuously, reducing the time for frequent adjustment and waiting of the equipment. In the one-time molding process, the equipment can complete multiple processes continuously after setting the parameters, reducing these non-productive time losses and improving the utilization rate of the equipment and the overall production efficiency.

[0042] Through the one-time molding process, the inner and outer sheaths are more tightly integrated with each other and with the internal structures such as the cable core. For example, during the longitudinal wrapping A2 and the extrusion process B2, they can better match the structure of the inner sheath after oil filling and the first layer of sheath formed by the extrusion process B1. During the extrusion process B2, the mold size can be accurately adjusted according to the actual outer diameter of the cable after the extrusion process B1 to ensure that the total thickness of the two layers of sheath and the overall outer diameter of the cable meet the design requirements, thereby improving the consistency of the cable size accuracy.

[0043] The one-time molding process of inner and outer guards merges two originally separate production lines into a whole, reducing duplicate investment in equipment. There is no need to set up independent extruders, longitudinal wrapping machines and other equipment for the inner and outer guards respectively, thus reducing equipment procurement costs. At the same time, due to process integration, the floor space of the production line is also reduced accordingly, saving the cost of renting or building a factory. Compared with traditional processes, enterprises can achieve the same or even higher production capacity with less equipment and site investment.

[0044] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0045] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A one-step molding production process for double-sheath cable, characterized in that: It includes S1: coloring process, S2 plastic coating process, S3 cabling process, S4 sheathing process. S4 sheathing process is a one-time molding process for inner and outer sheaths. The specific steps are as follows S40, cable core pay-off; S41, cable paste filling, injecting the cable paste into the gap of the cable core, the cable paste is made of vaseline, paraffin wax, antioxidants, preservatives and other additives, and the cable paste is smoothly introduced into the gap of the cable core through a pressure filling device; S42, longitudinal wrapping process A1, using metal strips or plastic film strips to wrap longitudinally along the cable core axis; S43, extrusion process B1, the extruder extrude a first layer of sheath material on the cable core structure, wherein the first layer of sheath material is polyethylene or polyvinyl chloride; S44, traction cooling C1, the traction machine pulls the extruded cable core at a uniform speed, and drives the cable core to move by friction through the traction wheel with rubber pad; S45, inner sheath oil filling, through the special oil filling equipment, the oil is injected into the space between the inner sheath and the cable core at a pressure of about 0.2-0.4MPa; S46, longitudinal wrapping process A2, in which a steel belt or a plastic belt with good oil resistance is used; S47, extrusion process B2, the thickness of the sheath extruded by the extrusion process B2 is thicker than that of B1; S48, traction cooling C2, the traction machine continues to pull the cable through the cooling device at a constant speed; S49, reel in the line.

2. A cable double sheath one-step molding production process according to claim 1, characterized in that: In the S41, the filling pressure is 0.1-0.3MPa, and the filling amount accounts for 75%-85% of the cable core gap volume; in the S42, if it is an aluminum tape longitudinal wrap, the width of the aluminum tape is selected according to the cable core circumference and the longitudinal wrap overlap requirements, the overlap width is 5-10mm, to form a continuous and sealed wrapping layer, the thickness of the aluminum tape is 0.2-0.5mm, and in the S43, the temperature of the extruder feeding section is 140-160℃, the temperature of the compression section is 160-180℃, and the temperature of the metering section is 180-200℃.

3. The one-step molding production process for double-sheathed cables according to claim 1 is characterized in that: In the S46 and longitudinal wrapping process A2, the overlap width is between 8-12 mm, the steel belt thickness is within the range of 0.5-1.0 mm, and the plastic belt used in A2 is a tetrafluoroethylene (PTFE) belt or a specially formulated polyethylene (PE) belt that will not swell or deteriorate in performance in an oil environment.

4. The one-step molding production process for double-sheathed cables according to claim 1 is characterized in that: The thickness of the sheath extruded by B1 is between 1.5-2.5 mm, and the thickness of the sheath extruded by B2 is between 2.0-3.0 mm.

5. The one-step molding production process for double-sheathed cables according to claim 1 is characterized in that: In the S44 and traction cooling C1, the traction machine is provided with tension feedback and adjustment functions, real-time monitoring and automatic adjustment of the cable core traction tension, and the cooling methods include water cooling, air cooling or a combination of the two. When water cooling, the water temperature of the water cooling tank is controlled at 10-30°C, and the water flow speed ensures that the heat of the sheath is taken away, so that the sheath is quickly cooled and shaped; when air cooling, the fan provides cold air blowing cooling with a wind speed of 2-10 m / s.

6. A one-step molding production process for double-sheathed cables according to claim 5, characterized in that: In the S48 and traction cooling C2 processes, the specific structure and production speed of the water-cooling tank water temperature cable are between 10-30°C, and the air cooling wind speed is in the range of 2-10 m / s.

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