Medium-voltage cable production equipment and method

Abstract

The invention discloses production equipment of a medium-voltage cable. The production equipment comprises a conductor preheater; the machine head is coupled to the downstream of the conductor preheater; the upper sealing heater is coupled to the downstream of the machine head; a processing section coupled downstream of the upper sealed heater, the processing section comprising a plurality of sub-processing sections, each of the sub-processing sections comprising a heating unit; the heating unit is configured to be activated in a first mode and not activated in a second mode; the processing section further comprises a pre-cooling circulation device, and the pre-cooling circulation device is configured to be bypassed in the first mode and started in the second mode to provide a low-temperature medium for the sub-processing section communicated with the pre-cooling circulation device so as to pre-cool the second cable material in the sub-processing section. According to the medium-voltage cable production line, a production line for independently producing the XLPE cable and a production line for independently producing the PP cable are integrated into one production line, so that the flexibility of a manufacturer is greatly improved.

Description

Technical Field

[0001] The invention relates to a production method and equipment for medium voltage (6KV-35KV) cables, in particular to a production method and equipment for XLPE (cross-linked polyethylene) and PP (polypropylene) cables. Background Art

[0002] With the development of economy and urban construction, my country has built a large-scale power cable network. Among them, cross-linked polyethylene (XLPE) has become the most commonly used insulation material for power cables with its excellent heat resistance, dielectric properties and mechanical properties. However, with the large-scale use of XLPE cables, problems in manufacturing, production and decommissioning and recycling have gradually emerged. On the one hand, the production of XLPE cables is time-consuming and energy-intensive; on the other hand, XLPE is a thermosetting polymer with a special cross-linked network structure. After the XLPE cable is retired, its insulation layer is difficult to degrade and difficult to be processed and reused. With the concept of environmental protection and energy conservation becoming a global trend and the proposal of the "dual carbon" goal, the cable industry has also begun to conduct research on low-carbon environmental protection, material innovation, and recycling and reuse.

[0003] At present, there are many common problems in the production of XLPE cables and PP cables by medium-voltage cable production lines on the market. First, the medium-voltage cable line produces XLPE cables and PP cables separately using two production lines. Second, when using one production line to produce medium-voltage XLPE cables and PP cables, it is not possible to handle the roundness and eccentricity problems of PP cables well. Third, PP cables require progressive cooling during production, and the cooling problem cannot be handled well. Fourth, it is difficult to switch the pipeline operation between the two production modes when the medium-voltage production line produces XLPE cables and PP cables.

[0004] Therefore, it is necessary to propose an improved production line, which can be based on the current common domestic production of XLPE cable production line, and can produce both XLPE cables and PP cables well. Summary of the invention

[0005] Therefore, the purpose of the present invention is to propose an improved production line that can produce both XLPE cables and environmentally friendly PP cables, and the products produced are of high quality, thereby saving customers' production equipment investment and labor investment.

[0006] To this end, the present invention proposes a production equipment for medium-voltage cables, which includes a conductor preheater, configured to preheat a first cable conductor material in a first mode and to preheat a second cable conductor material in a second mode; a machine head coupled to the downstream of the conductor preheater, configured to perform internal and external shielding and wrapping of a first insulating material layer on the first cable conductor material in the first mode to obtain a first cable material, and to perform internal and external shielding and wrapping of a second insulating material layer on the second cable conductor material in the second mode to obtain a second cable material; an upper sealing heater coupled to the downstream of the machine head, configured to insulate the first cable material only in the first mode; a processing section coupled to the downstream of the upper sealing heater, the processing section including a plurality of sub-processing sections, each of the sub-processing sections including a heating unit; The heating unit is configured to be activated in the first mode to cross-link and vulcanize the first cable material therein at high temperature to obtain a first cable, and is not activated in the second mode; the processing section also includes a pre-cooling circulation device, which is connected between the upstream sub-processing section and the downstream sub-processing section; the pre-cooling circulation device is configured to be bypassed in the first mode, and to be started in the second mode to provide a low-temperature medium to the sub-processing section connected thereto to pre-cool the second cable material therein so as to adjust its roundness and eccentricity to obtain a second cable; and a cooling circulation system coupled to the downstream of the processing section, the cooling circulation system providing a cooling section for cooling the first cable in the first mode and cooling the second cable in the second mode.

[0007] In some embodiments, the processing section also includes the pre-cooling circulation device being an OSR pre-cooling circulation device, and the low-temperature medium being liquid nitrogen.

[0008] In some embodiments, in some embodiments, the cooling cycle system includes a first water vapor balance, and the first water vapor balance is connected between the processing section and the cooling section.

[0009] In some embodiments, the cooling cycle system includes a second water vapor balance, which is connected between any sub-processing section downstream of the sub-processing section where the pre-cooling cycle device is installed and the cooling section.

[0010] In some embodiments, in some embodiments, at least one of the sub-processing sections further comprises a temperature measuring unit.

[0011] In some embodiments, a short transmitting device of a drape measurement system is provided at the front of the middle sub-processing section of the processing section, and a receiving device of the drape measurement system is provided at the rear, and the position of the cable of the entire production line is controlled by the drape measurement system.

[0012] In some embodiments, the first insulating material layer is a cross-linked polyethylene (XLPE) material layer, and the second insulating material layer is a polyethylene (PP) material layer.

[0013] The technical effect of the present invention is that the proposed medium-voltage cable production line integrates the production line for producing XLPE cables and the production line for producing PP cables into one production line, thereby greatly improving the flexibility of the manufacturer. Among them, the roundness and eccentricity problems of PP cables can also be well solved. The production efficiency of the entire medium-voltage production line is improved. The investment cost of the cable manufacturer is saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of a medium voltage cable production equipment according to an embodiment of the present application.

[0015] Figure 2 This is a schematic diagram of the pipeline operation when the production equipment according to an embodiment of the present application produces XLPE cables alone.

[0016] Figure 3 This is a schematic diagram of the pipeline operation of the production equipment according to the embodiment of the present application for producing PP cables alone. DETAILED DESCRIPTION

[0017] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0020] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0021] The main technical core of the entire cable production line of the present invention lies in the pipeline principle of the cable production line. The pipeline principle diagram of the medium voltage line production equipment combines the advantages of the pipeline principles of XLPE cable and PP cable production lines, and optimizes and improves efficiency.

[0022] In general, the medium voltage cable production equipment according to the embodiments of the present application works in at least two modes, for example, in a first mode it is used to manufacture a first cable, such as an XLPE cable, and in a second mode it is used to manufacture a first cable, such as a PP cable.

[0023] Figure 1 is a schematic structural diagram of a medium voltage cable production device according to an embodiment of the present application, Figure 1 It can be seen that the medium voltage cable production equipment 100 includes a conductor preheater 10, a die head 20, an upper sealing heater 30, a processing section 40 and a cooling circulation system 50 coupled from upstream to downstream. For example, the conductor preheater 10 is connected to the die head 20 at the output end of the conductor preheater 10 through a pipeline, the upper sealing heater 30 at the output end of the die head is connected to the upper sealing heater 30 through a pipeline, and the processing section 40 is connected to the output end of the upper sealing heater 30 through a pipeline.

[0024] The conductor preheater 10 is configured to preheat the first cable conductor material, such as copper, aluminum, alloy material, etc., in the first mode, and preheat the second cable conductor material, such as copper, aluminum, alloy material, etc., in the second mode; the head 20 can be a three-layer co-extrusion head, configured to perform internal and external shielding and a first insulating material layer, such as XLPE wrapping, on the first cable conductor material in the first mode to obtain the first cable material, and perform internal and external shielding and a second insulating material layer, such as PP material wrapping, on the second cable conductor material in the second mode to obtain the second cable material; the upper sealing heater is configured to only keep the first preformed cable warm in the first mode, and not be activated in the second mode, so that. The processing section 40 is used to heat the first cable material in the first mode so that its insulating layer material undergoes sufficient cross-linking and vulcanization, and in the second mode, the second cable material is not heated, but is pre-cooled by a pre-cooling circulation device.

[0025] The processing section includes a plurality of sub-processing sections 401, 402, 403 to 40N arranged from upstream to downstream, and each sub-processing section includes a heating component. The heating components in each sub-processing section are configured to heat each sub-processing section when used for XLPE cable production. The processing section 40 also includes an OSR pre-cooling circulation device (i.e., an online nitrogen pre-cooling circulation system) 41. The pre-cooling circulation device 41 includes a cooling gas output terminal 411 and a cooling gas recovery terminal 412. The cooling gas output terminal 411 is connected to the input terminal of a sub-processing section of the processing section 40, and the cooling gas recovery terminal 412 is connected to the output terminal of another downstream sub-processing section. For example, the cooling gas output terminal 411 can be connected to the first sub-processing section 401, and the cooling gas recovery terminal 412 can be connected to the output terminal of the seventh sub-processing section 407. In this way, the cooling gas can cool the PP cable in a sub-cooling section of a specific length as needed, so as to achieve the purpose of ensuring the roundness and eccentricity of the PP cable. Figure 3 As shown, the OSR precooling cycle device generally includes a controlled nitrogen gas source, a throttle valve, an input switch valve, an output switch valve and other components.

[0026] In some embodiments, the number of sub-processing sections in the processing section can be customized according to customer requirements and the customer's factory environment. The sub-processing sections can be divided into high-temperature sub-processing sections and low-temperature sub-processing sections. The number of high-temperature sub-processing sections and low-temperature sub-processing sections in each production line is different according to the total number of sub-processing sections.

[0027] In some embodiments, each sub-processing section can be an independent component. For example, each sub-processing section can have an independent heating unit and temperature measuring unit, for example, sub-processing section 401 includes a heating unit 4011 and a temperature measuring unit 4012. Of course, the heating unit and the temperature measuring unit can also be provided with one heating unit and one temperature measuring unit for every two sub-processing sections.

[0028] In some embodiments, a short transmitting device of a drape measurement system is provided at the front of the middle section of the processing section, and a receiving device of the drape measurement system is provided at the rear, and the position of the cable of the entire production line is controlled by the drape measurement system.

[0029] A cooling circulation system 50 is connected downstream of the processing section 40. The cooling circulation system provides a cooling section 53, and may also include at least one water vapor balance tank, for example, may include a first water vapor balance tank 51 connected to the output end of the most downstream sub-processing section 409. In some embodiments, for example, a second water vapor balance tank 52 may also be included, and the second water vapor balance tank 52 may be configured to be installed on the output end of the next sub-processing section 408 of the sub-processing section 407 connected to the cooling gas recovery end 412, so that the PP cable can enter the cooling circulation system 50 as early as possible.

[0030] Figure 2 This is the pipeline operation schematic diagram of the production line when producing XLPE cables alone. Figure 2 The red box in the figure is the area where the processing section 40 is located. When producing XLPE cables, the metal conductors of the cables must be preheated so that they can better bond with the inner and outer shielding and insulation materials of the cables. When the conductors preheated by the conductor preheater 10 pass through the machine head 20 for three-layer co-extrusion, they are bonded with the shielding layer and the insulation layer at the machine head 20. After being heated and insulated by the upper sealing heater 30, the conductors enter the area where the processing section 40 is located and begin to fully cross-link and vulcanize the XLPE cable in this area. Cross-linking and vulcanization require sufficient heat and time. Therefore, in this process, the processing section 40 can be configured to provide heat to the cable materials passing through it through the heating units of each sub-processing section. This stage is also the stage where the XLPE cable consumes a lot of energy and produces waste gases and by-products such as sulfides. The fully cross-linked and vulcanized cable enters Figure 2 The cooling section 53 provided by the cooling circulation system 50 shown in the middle blue is used for cooling. For the production of XLPE cables, the first water vapor balance tank 51 is used as a transition section between the processing section and the cooling section 53. This first water vapor balance tank 51 can be equipped with a magnetic flap liquid level display device, so that the height of the water level in the cooling pipe and the size of the air pressure in the heating section can be controlled to ensure the smooth operation of the pipeline. The first water vapor balance tank between the processing section and the cooling circulation system 50 allows the XLPE cable to have more heating areas. The cooling circulation system 50 is for fully water cooling the cross-linked and vulcanized XLPE cable. The temperature of the XLPE cable is about 40 degrees Celsius at the XLPE cable reel. So that the outer surface of the XLPE cable will not be deformed when the XLPE cable is reeled.

[0031] A major feature of the production equipment in this application is that in the same production line, when PP cables need to be produced, it can be switched to PP cable mode. Figure 3 Shown is the pipeline principle operation diagram for PP cable production.

[0032] from Figure 3 It can be seen that the metal conductor inside the PP cable also needs to be preheated by the conductor preheater 10 to better bond with the inner shielding layer. The preheated conductor is wrapped with the inner and outer shields and insulation layers by the three-layer co-extrusion head 20. Since the production of PP cables does not require high-temperature cross-linking vulcanization, the upper sealing heater 30 and the heating unit of the processing section 40 do not need to be started or heated for low-temperature insulation. No waste gas and waste such as sulfide will be generated. This is also the advantage of producing PP cables.

[0033] However, due to the good thermal fluidity of PP materials, after the PP cable is produced and wrapped with inner and outer screens and insulating materials through the machine head 20, it will tend to flow downward by gravity. If not handled properly, it will directly cause significant damage to the roundness and eccentricity of the cable material. This will lead to unqualified production of PP cables. The production equipment in this embodiment adds an OSR pre-cooling circulation device 41 at the output end of the upper sealing heater 30 and the last two sub-processing sections of the processing section 40. The OSR pre-cooling circulation device 41 is configured to provide low-temperature nitrogen at the output end of the upper sealing heater to directly act on the PP cable coming out of the upper sealing heater 30, that is, from the machine head 20, so that the surface of the PP cable rapidly produces a hard shell due to the low-temperature nitrogen, which prevents the downward flow of the PP material and maintains the roundness of the cable.

[0034] Since PP cables do not require heating or low temperature heating, cooling nitrogen is continuously circulated in the heating section to cool them. Figure 3 It can be seen that a second water vapor balance tank 52 can be provided for the production of PP cables. The second water vapor balance tank 52 can be arranged between the last sub-processing section 409 and the penultimate sub-processing section 408 of the processing section. This structure can make the length of the water cooling cycle provided by the cooling circulation system 50 longer, that is, one of the processing sections of the processing section is also used as a part of the cooling section, so as to achieve an earlier and longer cooling effect, and better ensure the cooling effect of the PP cable.

[0035] It should be understood that for different PP cable manufacturing, the second water vapor balance tank 52 can also be set at other positions, such as between two sub-processing sections further upstream, such as between the second to last sub-processing section and the third to last sub-processing section, so that the cooling section can be lengthened.

[0036] It should be understood that for different PP cable manufacturing, the second water vapor balance tank 52 can be omitted, that is, only the first water vapor balance tank 51 is provided, so that the length of the standard cooling section is utilized.

[0037] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A production equipment for medium voltage cables, characterized in that: include a conductor preheater configured to preheat a first cable conductor material in a first mode and to preheat a second cable conductor material in a second mode; A head coupled to the downstream of the conductor preheater is configured to perform inner and outer shielding and wrapping of the first insulating material layer on the first cable conductor material in the first mode to obtain a first cable material, and perform inner and outer shielding and wrapping of the second insulating material layer on the second cable conductor material in the second mode to obtain a second cable material; an upper seal heater coupled downstream of the handpiece and configured to maintain temperature of the first cable material only in the first mode; A processing section coupled to the downstream of the upper sealing heater, the processing section comprising a plurality of sub-processing sections, each of the sub-processing sections comprising a heating unit; the heating unit is configured to be activated in the first mode to cross-link and vulcanize the first cable material therein at a high temperature to obtain a first cable, and not activated in the second mode; The processing section further comprises a pre-cooling circulation device, which is connected between the upstream sub-processing section and the downstream sub-processing section; the pre-cooling circulation device is configured to be bypassed in the first mode, and to be started in the second mode to provide a low-temperature medium to the sub-processing section connected thereto to pre-cool the second cable material therein so as to adjust its roundness and eccentricity to obtain a second cable; and a cooling circulation system coupled downstream of the processing section, the cooling circulation system providing a cooling section for cooling the first cable in the first mode and cooling the second cable in the second mode.

2. The production equipment of medium voltage cables according to claim 1, characterized in that: The processing section also includes the pre-cooling circulation device which is an OSR pre-cooling circulation device, and the low-temperature medium is liquid nitrogen.

3. The production equipment of medium voltage cables according to claim 1, characterized in that: The cooling circulation system comprises a first water vapor balance, which is connected between the processing section and the cooling section.

4. The production equipment of medium voltage cables according to claim 1, characterized in that: The cooling circulation system comprises a second water vapor balance, which is connected between any one of the sub-processing sections downstream of the sub-processing section where the pre-cooling circulation device is installed and the cooling section.

5. The production equipment of medium voltage cables according to claim 1, characterized in that: At least one of the sub-processing sections further comprises a temperature measuring unit.

6. The production equipment of medium voltage cables according to claim 1, characterized in that: A transmitting short device of a droop measuring system is provided at the front of the middle sub-processing section of the processing section, and a receiving device of the droop measuring system is provided at the rear. The position of the cable of the entire production line is controlled by the droop measuring system.

7. The production equipment of medium voltage cables according to claim 1, characterized in that: The first insulating material layer is a cross-linked polyethylene material layer, and the second insulating material layer is a polyethylene material layer.

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