Experimental device for submarine cable flexible joint forming process research

Abstract

The utility model relates to an experimental device for submarine cable flexible joint forming process research, a forming cavity is arranged in a forming die, the forming die comprises at least two unit dies, and each unit die is provided with a unit groove; the unit mold is provided with a material inlet and a functional interface which are communicated with the forming cavity, the heating unit is used for transferring heat to the forming cavity of the forming mold, the monitoring unit at least comprises a temperature acquisition device and a pressure acquisition device, the temperature acquisition device is used for acquiring temperature data, and the pressure acquisition device is used for acquiring pressure data. The experimental device can simulate the whole technological process, quantify technological parameters such as temperature and pressure, perform temperature monitoring and pressure monitoring on an extrusion preheating stage, an insulation extrusion stage, a vulcanization stage and the like, realize quantitative research on the technological parameters, systematically research the incidence relation between the technological parameters and the interface performance, and improve the interface performance. Efficient transfer from research and development to key production processes is achieved, and research results can be directly used for product manufacturing.

Description

Technical Field

[0001] The present application relates to the technical field of submarine power cables, and in particular to an experimental device for studying the molding process of submarine cable flexible joints. Background Art

[0002] High-voltage submarine cable systems are the only viable transmission medium for cross-sea power transmission and offshore renewable energy access. Currently, offshore wind power is gradually developing towards larger capacity, greater offshore reach, and greater scale, placing more stringent demands on offshore wind power technology and equipment. As a crucial supporting product for offshore wind power, submarine cables face key technical bottlenecks in long-length manufacturing, product structural design, flexible joint connections, and product testing. In long-distance submarine cable applications, due to limitations in the continuous cable extrusion process, the maximum length of cross-linked polyethylene (XLPE) insulated submarine power cables can only reach 20km-30km. A single, jointless submarine cable cannot meet the requirements of deep-sea power transmission. Therefore, flexible joints are required to connect two sections of submarine power cable to ensure the continuity and reliability of the cable system. Submarine cable flexible joints, essential core components for submarine cable splicing, represent a cutting-edge technological challenge within the industry, a significant factor restricting the development of submarine cable systems and crucial for the normal and reliable operation of the entire submarine cable transmission system.

[0003] Cross-linked polyethylene insulated submarine power cables utilize chemical or physical methods to transform the polyethylene from a linear molecular structure to a network structure, converting thermoplastic polyethylene into thermosetting cross-linked polyethylene. This significantly improves its heat resistance and mechanical properties, preventing it from melting under heat while maintaining excellent electrical insulation properties. Insulation restoration for submarine cable flexible joints is a core technology and the most challenging step in the entire process to master and control. Its ultimate goal is to achieve performance matching and good interface performance between the restored insulation and the underlying cable insulation. However, the polyethylene material of the underlying cable is already cross-linked, making it difficult to improve the secondary bonding between the re-extruded insulation and the underlying insulation. This is because the cross-linked underlying insulation already has a very low content of active crosslinks, maintaining a stable overall shape and forming an infusible cross-linked network structure. Therefore, efficient chemical cross-linking of the re-extruded insulation with the underlying insulation is difficult. Therefore, research on insulation restoration processes to improve interface performance is a core component of flexible joint technology and is key to achieving stable quality and high yield rates for ultra-high voltage (UHV) submarine cable flexible joints.

[0004] During the extrusion molding and cross-linking vulcanization process of the flexible joint insulation layer, molding process parameters (temperature, pressure, time, interface treatment, etc. involved in insulation material extrusion, vulcanization, and degassing) significantly influence the quality of the flexible joint molding, directly determining the quality of the flexible joint's restored insulation layer and insulation interface. If this type of experimental research were conducted on conventional flexible joint product molds, each process parameter adjustment would require an iteration cycle of up to five days, requiring 4-6 people to conduct the experiments. This would be labor-intensive and material-intensive, and the lack of monitoring capabilities for internal melt parameters such as temperature and pressure made it impossible to conduct scientific and quantifiable process research iterations.

[0005] Currently, the development of flexible submarine cable joints lacks process simulation equipment. This leads to a series of problems, such as long process iteration cycles, high resource investment, difficulty in clarifying the mechanism, and difficulty in improving product consistency. This makes it difficult to meet the R&D needs of ultra-high voltage submarine cable flexible joints. Therefore, it is necessary to design test plans and experimental equipment to quickly verify the impact of different molding process parameters on the quality of flexible joints and to determine the influence of different parameters. Utility Model Content

[0006] Based on this, it is necessary to provide an experimental device for studying the molding process of submarine cable flexible joints in response to the above-mentioned technical problems.

[0007] The present application provides an experimental device for studying a forming process of a submarine cable flexible joint, the experimental device comprising:

[0008] A molding die having a molding cavity therein, the molding die comprising at least two unit molds, each of the unit molds being provided with a unit groove, a plurality of the unit molds being used to be spliced ​​together to form the molding die, and a plurality of the unit grooves being used to collectively form the molding cavity; at least one of the unit molds being provided with a material inlet and a functional interface communicating with the molding cavity;

[0009] a heating unit connected to the forming mold, and configured to transfer heat to the forming cavity of the forming mold;

[0010] A monitoring unit is connected to the molding die, and the monitoring unit includes at least a temperature acquisition device and a pressure acquisition device. The temperature acquisition device is used to obtain temperature data in the molding cavity, and the pressure acquisition device is used to obtain pressure data in the molding cavity.

[0011] In one embodiment, the forming mold comprises:

[0012] a first unit mold, wherein the first unit mold is provided with a first unit groove;

[0013] a second unit mold, wherein the second unit mold is provided with a second unit groove;

[0014] The first unit mold and the second unit mold are used to be spliced ​​together to form the molding mold, so that the first unit groove and the second unit groove together constitute the molding cavity; the second unit mold is located below the first unit mold, and the material inlet is opened in the second unit mold.

[0015] In one embodiment, the experimental setup includes:

[0016] A mold liner is detachably arranged on the inner wall of the molding cavity.

[0017] In one embodiment, the experimental setup includes:

[0018] A feeding assembly, wherein the feeding assembly includes a feeding pipe, the inner cavity of the feeding pipe is connected to the material inlet, wherein one pipe end of the feeding pipe extends from the material inlet into the molding chamber, and the pipe end of the feeding pipe extending into the molding chamber is flush with the surface of the mold lining facing the molding chamber.

[0019] In one embodiment, the experimental setup includes:

[0020] A connecting component, the connecting component includes a connecting pipe and a control valve body, the inner cavity of the connecting pipe is connected to the functional interface, the connecting pipe is used to connect at least the degassing component and the pressurizing component, and the control valve body is arranged on the connecting pipe to control the opening or closing of the inner cavity of the connecting pipe.

[0021] In one embodiment, the experimental device includes a pressurizing component, which is connected to the molding cavity of the molding die through the functional interface and is used to pressurize the molding cavity; or

[0022] The experimental device includes a degassing component, which is connected to the molding cavity of the molding die through the functional interface and is used to achieve degassing of the molding cavity; or,

[0023] A degassing hole communicating with the internal unit grooves of at least one of the unit molds is provided on the surface of the unit mold.

[0024] In one embodiment, the experimental setup includes:

[0025] A positioning component is connected to the molding die and is used to position the sample at a predetermined spatial position in the molding cavity.

[0026] In one embodiment, the molding mold has a first position and a second position. In the molding chamber, the direction from the first position to the second position is configured as the melt filling timing direction. The material inlet is opened at the first position of the molding mold, and the functional interface is opened at the second position of the molding mold.

[0027] In one embodiment, the heating unit is arranged outside the forming mold or in a forming cavity inside the forming mold; and / or,

[0028] The heating unit includes at least one of a heating tile, a heating rod and a heating wire.

[0029] In one embodiment, the monitoring unit includes a control device, which is controllably connected to the temperature acquisition device and the heating unit.

[0030] The above-mentioned experimental device used for the research on the forming process of submarine cable flexible joints can simulate the entire process flow of shielding layer recovery, insulation recovery and degassing. Compared with conventional flexible joint product molds, the experimental device integrates a heating unit and a monitoring unit, which can quantify process parameters such as temperature and pressure. It can monitor the temperature and pressure of key process links such as the extrusion preheating stage, insulation extrusion stage, and vulcanization stage, realize quantitative research on process parameters, systematically study the correlation between process parameters and interface performance, and realize efficient transfer of key process technologies from research and development to production. The research results can be directly used in product manufacturing.

[0031] During process research, a single straightening operation can produce no fewer than 10 submarine cable insulation cutting cones. This allows for a sufficient supply of these cones at once, simplifying process implementation and shortening the process development cycle, reducing the iterative development cycle for restoring process parameters from 5-7 days to 1-2 days. This also reduces experimental material costs, potentially down to about a quarter of the original total, and reduces human resources from five to just two.

[0032] Furthermore, the experimental setup enables the extrusion, nitrogen pressurization, cross-linking, vulcanization, and vacuum degassing processes of the submarine cable flexible joint insulation layer to be completed within a single mold. This allows for both one-step and two-step processes, significantly improving the efficiency of process research iterations and enabling quantitative analysis of process parameters. The experiment consisted of three stages: cross-linked polyethylene extrusion, vulcanization, and degassing. The cross-linked polyethylene extrusion stage primarily examined the impact of parameters such as melt temperature, mold temperature, extrusion pressure, and dwell time on product performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A stereoscopic image of an experimental device provided in an embodiment of the present application from a first perspective.

[0034] Figure 2 A stereoscopic image from a second perspective of an experimental device provided in one embodiment of the present application.

[0035] Figure 3 A three-dimensional diagram of an experimental device provided in another embodiment of the present application.

[0036] Figure 4 A three-dimensional exploded view of an experimental device provided in one embodiment of the present application.

[0037] Figure Number:

[0038] 100, sample; 1000, molding mold; 2000, heating unit; 3000, monitoring unit; 4000, feeding assembly; 5000, connecting assembly; 1000a, molding chamber; 1000b, degassing hole; 1100, unit mold; 1100a, first unit mold; 1100b, second unit mold; 1200, mold lining. DETAILED DESCRIPTION

[0039] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0040] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0041] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0042] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0043] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0044] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0045] See Figures 1 to 4As shown, the present application provides an experimental device for studying the molding process of submarine cable flexible joints. The experimental device can simulate the process form of submarine cable flexible joint insulation recovery, thereby realizing a systematic study of the submarine cable flexible joint insulation recovery process. The experimental device may include a molding mold 1000, a heating unit 2000, and a monitoring unit 3000. The molding mold 1000 has a molding chamber 1000a inside. The molding mold 1000 includes at least two unit molds 1100. Each unit mold 1100 is provided with a unit groove. Several unit molds 1100 are used to be spliced ​​together to form the molding mold 1000. Several unit grooves are used to collectively form the molding chamber 1000a. At least one unit mold 1100 is provided with a material inlet and a functional interface connected to the molding chamber 1000a. The material inlet can be used to pour material, such as cross-linked polyethylene plastic melt, into the molding chamber 1000a. The functional interface can be used to connect other required functional components, such as pressurization components, degassing components, etc., so as to use the functional interface to achieve the required functions, such as pressurization function, degassing function, etc. Technical personnel in this field can use the functional interface to achieve the required functions according to needs, and there is no limitation here.

[0046] The heating unit 2000 is connected to the molding die 1000 and is used to transfer heat to the molding chamber 1000a of the molding die 1000, thereby heating the interior of the molding chamber 1000a and controlling the ambient temperature within the molding chamber 1000a. The monitoring unit 3000 is connected to the molding die 1000 and includes at least a temperature acquisition device and a pressure acquisition device. The temperature acquisition device is used to acquire temperature data within the molding chamber 1000a, and the pressure acquisition device is used to acquire pressure data within the molding chamber 1000a. For example, the molding die 1000 can monitor the melt temperature and melt pressure at one or more points in different areas, monitoring the temperature and pressure of the insulating melt throughout the entire mold filling process, quantifying process parameters and improving product consistency. Furthermore, the monitoring unit 3000 may also include acquisition devices for acquiring other data within the molding chamber 1000a, such as time data and humidity data. Those skilled in the art can select appropriate acquisition devices to meet their data collection needs, and this is not limited here.

[0047] The molding die 1000 can be provided with an appropriate number of unit molds 1100 as required. Several unit molds 1100 can be spliced ​​together to form a complete molding die 1000, and several unit grooves can be used to form a complete molding chamber 1000a. Therefore, the complete molding chamber 1000a can be used to mold the required sample 100, such as an experimental cable (submarine cable flexible joint). When the several unit molds 1100 are separated from each other, the sample 100 in the molding chamber 1000a can be easily removed from the molding chamber 1000a. The several unit molds 1100 can be detachably spliced ​​together in a variety of ways. For example, different unit molds 1100 can be spliced ​​together in a variety of detachable ways such as threaded connection, snap connection, magnetic connection, etc., which are not limited here. In addition, sealing materials such as sealing rings and sealing strips can be provided between the several unit molds 1100 to ensure the sealing of the molding chamber 1000a formed after splicing.

[0048] The material inlet and the functional interface can be set to a suitable size and shape and be located at a suitable position as required, for example, in the same unit mold 1100 or in different unit molds 1100. For example, in one embodiment, the molding mold 1000 has a first position and a second position, which can be defined in the molding chamber 1000a. The direction from the first position to the second position is configured as the melt filling timing direction, that is, the flow direction of the melt from the material inlet into the molding chamber 1000a until the molding chamber 1000a is filled. In this case, the material inlet can be opened at the first position of the molding mold 1000, and the functional interface can be opened at the second position of the molding mold 1000. Therefore, the melt will enter the molding chamber 1000a from the material inlet and then gradually flow toward the functional joint.

[0049] In one embodiment, the molding mold 1000 may include two unit molds 1100, which may be referred to as a first unit mold 1100a and a second unit mold 1100b. The unit grooves provided in the first unit mold 1100a are referred to as first unit grooves, and the unit grooves provided in the second unit mold 1100b are referred to as second unit grooves. In this case, the first unit mold 1100a and the second unit mold 1100b may be used to be joined together to form the molding mold 1000, such that the first unit grooves and the second unit grooves together constitute the molding cavity 1000a. In this embodiment, the first unit mold 1100a and the second unit mold 1100b may be arranged up and down to form an upper mold and a lower mold. For example, the second unit mold 1100b is located below the first unit mold 1100a, with the first unit mold 1100a serving as the upper mold and the second unit mold 1100b serving as the lower mold. At this time, the material inlet is opened in the second unit mold 1100b. When it is necessary to pour the material into the molding chamber 1000a, the material can be poured into the molding chamber 1000a from the bottom to the top.

[0050] In one embodiment, the experimental device includes a mold liner 1200, which is detachably arranged on the inner wall of the molding chamber 1000a. The mold liner 1200 can be made of polytetrafluoroethylene, silicone rubber or other polymer materials that are easy to demold. The function of the mold liner 1200 is to realize the demolding of the product after extrusion, pressure buffering during extrusion, and buffering the impact of fluctuations in mold temperature control on the product surface. Moreover, another important function of the mold liner 1200 is to generate a cavity of a certain thickness between the sample 100 and the molding chamber 1000a of the molding mold 1000 after removing the mold liner 1200. The generated cavity can be used to fill inert gases such as nitrogen to achieve pressurization and protective atmosphere, and the cavity can be used to implement a vacuum degassing process.

[0051] The material can be poured into the molding chamber 1000a through the material inlet in various ways. For example, in one embodiment, the experimental device may include a feed assembly 4000, which includes a feed pipe. The inner lumen of the feed pipe is connected to the material inlet. Thus, the feed pipe can be connected to a material delivery source and the material can be injected into the material inlet and molding chamber 1000a through the inner lumen of the feed pipe. One end of the feed pipe extends from the material inlet into the molding chamber 1000a, and the end of the feed pipe that extends into the molding chamber 1000a is flush with the surface of the mold liner 1200 facing the molding chamber 1000a. It should be noted that the mold lining 1200 is detachably fitted to the inner wall of the molding chamber 1000a, and the mold lining 1200 has a certain thickness. Therefore, the end of the pipe where the feed pipe is inserted is flush with the surface of the mold lining 1200 facing the molding chamber 1000a, which can ensure that the spatial shape inside the molding chamber 1000a is not destroyed by the inserted feed pipe.

[0052] In one embodiment, an experimental device includes a connection assembly 5000, which includes a connecting pipe and a control valve body. The inner lumen of the connecting pipe communicates with the functional interface. The connecting pipe serves as an intermediate indirect connection structure and is used to connect at least the degassing assembly and the pressurizing assembly, that is, to connect at least the degassing assembly and the pressurizing assembly to the functional interface via the connecting pipe. The control valve body is disposed on the connecting pipe and can be various mechanical valves or electronic valves, without limitation herein. The control valve body functions to control the opening or closing of the inner lumen of the connecting pipe.

[0053] It can be seen that the functional interface can be connected to different types of functional components, and thus different functions can be achieved when different functional components are connected. When the exhaust function is implemented, the control valve body is opened to discharge the air when the melt is filling the mold to the maximum extent. After the cavity is filled with the melt, the control valve body is closed to maintain sufficient pressure in the molding chamber 1000a. This is conducive to setting different molding holding pressures and verifying the effects of different pressures on the molding and cross-linking vulcanization quality of the submarine cable flexible joint. When nitrogen pressurization is implemented, high-pressure nitrogen or other inert gases are injected into the molding chamber 1000a through the control valve body for gas pressurization vulcanization. When vacuum degassing is implemented, a vacuum pump is connected to the functional interface to implement vacuum degassing, which can effectively discharge the gas and cross-linking by-products generated during the vulcanization process.

[0054] For example, in one embodiment, the experimental device may include a pressurizing component, which is connected to the molding chamber 1000a of the molding mold 1000 through a functional interface, and is used to pressurize the molding chamber 1000a. Alternatively, the experimental device may include a degassing component, which is connected to the molding chamber 1000a of the molding mold 1000 through a functional interface, and is used to degas the molding chamber 1000a. The degassing stage can implement vacuum degassing or open degassing. Among them, vacuum degassing mainly verifies the influence of degassing temperature and degassing time on the degassing effect of the sample 100 under a vacuum environment.

[0055] In addition, the open degassing mainly simulates the oven environment to verify the influence of degassing temperature and degassing time on the degassing effect of sample 100 under air convection environment. Figure 3 As shown, at least one unit mold 1100 may also have degassing holes 1000b on its surface that connect to the unit grooves within it. The number of degassing holes 1000b can be set as needed and evenly distributed across one or more unit molds 1100. The mold 1000 thus constructed is referred to as an open degassing mold and is used for open degassing in experiments. In one embodiment, the open degassing mold can be made of metal. The exterior of the open degassing mold can be heated externally, or a heating rod or heating wire can be embedded within the mold. The degassing holes 1000b can be circular holes or other regular or irregularly shaped hole structures, such as two or more strip-shaped holes, or circular, elliptical, or other through-holes in the open degassing mold. The purpose of the degassing holes 1000b is to utilize air convection to restore the insulation of the sample 100. Byproducts such as cumyl alcohol, acetophenone, styrene, methane, and water generated during heating are effectively and effectively removed in real time, shortening the degassing time and ensuring a gentler and more uniform removal process without damaging the restored insulation.

[0056] In one embodiment, the experimental apparatus includes a positioning assembly connected to the molding die 1000 and configured to position the sample 100 at a predetermined spatial location within the molding chamber 1000a. For example, the positioning assembly can be used to centrally secure the thin end of an experimental cable, preventing the cable from shifting off-center during the extrusion process.

[0057] In one embodiment, the heating unit 2000 is arranged on the outside of the forming mold 1000 or in the forming chamber 1000a inside the forming mold 1000. Moreover, the heating unit 2000 can adopt at least one of the heating elements such as heating tiles, heating rods and heating wires. For example, an external electric heating tile is adopted on the outside of the forming mold 1000, or a built-in heating rod or built-in heating wire is built into the forming chamber 1000a inside the forming mold 1000 for heating. In one embodiment, the monitoring unit 3000 includes a control device, which is connected to the temperature acquisition device and the heating unit 2000. The entire temperature rise and fall of the heating unit 2000 can use multi-point controlled thermocouples and control devices to jointly feedback and accurately control the mold temperature in different regions to verify the influence of different temperatures of extrusion, vulcanization and vacuum degassing on the molding quality of the submarine cable flexible joint.

[0058] The experimental setup simulates the entire process flow of shield restoration, insulation restoration, and degassing. Compared to conventional flexible joint molds, this setup integrates a heating unit 2000 and a monitoring unit 3000, quantifying process parameters such as temperature and pressure. Temperature and pressure monitoring are performed during key process steps, including the extrusion preheating stage, insulation extrusion, and vulcanization. This enables quantitative research on process parameters and systematically studies the correlation between process parameters and interfacial properties, effectively transferring key process technologies from R&D to production. Research findings can be directly applied to product manufacturing. During the process research, a single straightening operation can produce at least 10 submarine cable insulation cutting cones. This allows for a sufficient supply of these cutting cones at once, simplifying process implementation and shortening the process R&D cycle. The iterative R&D cycle for restoring process parameters has been reduced from 5-7 days to 1-2 days. This also reduces experimental material costs by approximately one-quarter, and reduces human resource requirements from five to just two.

[0059] Furthermore, the experimental setup enables the extrusion, nitrogen pressurization, cross-linking, vulcanization, and vacuum degassing processes of the submarine cable flexible joint insulation layer to be completed within a single mold. This allows for both one-step and two-step processes, significantly improving the efficiency of process research iterations and enabling quantitative analysis of process parameters. The experiment consisted of three stages: cross-linked polyethylene extrusion, vulcanization, and degassing. The cross-linked polyethylene extrusion stage primarily examined the impact of parameters such as melt temperature, mold temperature, extrusion pressure, and dwell time on product performance.

[0060] Among them, the one-step insulation recovery method refers to: the insulating material is extruded into the mold cavity, followed by vulcanization molding. For the one-step process, the vulcanization stage mainly verifies the influence of parameters such as vulcanization temperature and vulcanization time. The two-step insulation recovery method refers to: the insulating material is extruded into the mold cavity, and after cooling to a certain temperature, the mold is opened to remove the polytetrafluoroethylene or silicone rubber lining in the mold, and the sample is positioned and re-installed into the mold, followed by pressurized and heated vulcanization with nitrogen or other inert gases, and vacuum degassing or open degassing is performed after vulcanization is completed. For the two-step process, the vulcanization stage mainly verifies the influence of parameters such as vulcanization temperature, vulcanization time, and pressurization pressure of inert gases such as nitrogen on product performance.

[0061] In one embodiment of a one-step experimental method, the implementation process can be, for example:

[0062] The end face of the cable used for the experiment is stripped and the reaction force cone is processed as required. The reaction force cone is consistent with the structure of the flexible joint. The mold lining 1200 of polytetrafluoroethylene or high-temperature resistant silicone rubber located below is assembled into the second unit groove of the second unit mold 1100b located below. At the same time, the feed assembly 4000 is assembled. The end of the pipe extending into the feed pipe in the feed assembly 4000 is flush with the surface of the mold lining 1200 facing the molding chamber 1000a. The feed assembly 4000 is fixed to the feed table of the second unit mold 1100b with screws. A high-temperature resistant sealing ring is installed on the flange of the second unit mold 1100b. The processed experimental cable is placed in the mold lining 1200 of the second unit mold 1100b, and the positioning assembly is installed to center the thin end of the experimental cable.

[0063] Place the mold liner 1200 made of polytetrafluoroethylene or high-temperature resistant silicone rubber on the experimental cable, assemble the first unit mold 1100a from above the second unit mold 1100b, and install the mold liner 1200, the experimental cable, and the end positioning assembly into the first unit mold 1100a. Position the first unit mold 1100a and the second unit mold 1100b with pins and fasten them with bolts. Place the molding mold 1000 on the support frame and fasten it to the support frame with screws. Connect the heating component and temperature acquisition device outside the molding mold 1000 to the control device, set the heating temperature, and heat the molding cavity of the molding mold 1000.

[0064] Connect the extruder head to the material inlet of die 1000. After die 1000 reaches the set temperature, inject cross-linked polyethylene melt into the molding chamber 1000a of die 1000. Simultaneously, open the control valve of the sealing device to expel air from the molding chamber 1000a during the melt extrusion process. Once the molding chamber 1000a of die 1000 is filled, close the control valve to raise the cross-linked polyethylene melt pressure in the molding chamber 1000a to the target parameter (0.5-20 MPa as indicated on the pressure gauge). Extrusion time is adjustable from 1 to 20 minutes to promote fusion between the recovery insulation layer and the main insulation layer and to reduce pores. After the melt is fully injected and reaches the target pressure, increase the heating temperature of die 1000 to the vulcanization temperature to initiate high-temperature vulcanization of the cross-linked polyethylene. After vulcanization is complete, turn off the heating assembly. After the mold cools to below 35°C, open die 1000, remove the completed cable connector, and perform sampling and analysis.

[0065] By changing the parameters of the cross-linked polyethylene extrusion and vulcanization stages, repeating the above process, and comparing the results of the performance tests, we can find out the influence of different molding process parameters on the molding quality of the flexible joint experimental model.

[0066] In one embodiment of the two-step experimental method, the implementation process can be, for example:

[0067] The end face of the cable used for the experiment is stripped and the reaction force cone is processed as required. The reaction force cone is consistent with the structure of the flexible joint. The mold lining 1200 of polytetrafluoroethylene or high-temperature resistant silicone rubber located below is assembled into the second unit groove of the second unit mold 1100b located below. At the same time, the feed assembly 4000 is assembled. The end of the pipe extending into the feed pipe in the feed assembly 4000 is flush with the surface of the mold lining 1200 facing the molding chamber 1000a. The feed assembly 4000 is fixed to the feed table of the second unit mold 1100b with screws. A high-temperature resistant sealing ring is installed on the flange of the second unit mold 1100b. The processed experimental cable is placed in the mold lining 1200 of the second unit mold 1100b, and the positioning assembly is installed to center the thin end of the experimental cable.

[0068] Place the mold liner 1200 made of polytetrafluoroethylene or high-temperature resistant silicone rubber on the experimental cable, assemble the first unit mold 1100a from above the second unit mold 1100b, and install the mold liner 1200, the experimental cable, and the end positioning assembly into the first unit mold 1100a. Position the first unit mold 1100a and the second unit mold 1100b with pins and fasten them with bolts. Place the molding mold 1000 on the support frame and fasten it to the support frame with screws. Connect the heating component and temperature acquisition device outside the molding mold 1000 to the control device, set the heating temperature, and heat the molding cavity of the molding mold 1000.

[0069] Connect the extruder head to the material inlet of mold 1000. After mold 1000 reaches the set temperature, inject the cross-linked polyethylene melt into the molding chamber 1000a of mold 1000. Simultaneously, open the control valve of the sealing device to expel air from molding chamber 1000a during the melt extrusion molding process. Once molding chamber 1000a of mold 1000 is filled, close the control valve to raise the cross-linked polyethylene melt pressure in molding chamber 1000a to the target parameter (0.5-20 MPa as indicated on the pressure gauge). The extrusion time is adjustable from 1 to 20 minutes to promote the fusion of the interface between the recovery insulation layer and the main insulation layer and to compress pores.

[0070] After the melt is fully filled and reaches the target pressure, stop extrusion. After stabilization for 5-10 minutes, turn off the heating component. Wait for the molding mold 1000 to cool to the range of 70-75°C, open the molding mold 1000, and remove the polytetrafluoroethylene mold liner 1200. Place the molded experimental cable preform back into the molding mold 1000, assemble the positioning components at both ends to keep the experimental cable preform centered and the surrounding space as uniform as possible, and close the mold again to tighten the bolts.

[0071] Connect the high-pressure nitrogen cylinder line to the functional interface, open the control valve, and fill it with high-pressure nitrogen to the required pressure. Then close the control valve to maintain pressure. Simultaneously, turn on the heating assembly, set the vulcanization temperature and time curve, and begin high-temperature vulcanization of the cross-linked polyethylene. After vulcanization is complete, turn off the heating assembly, maintain the seal of the molding chamber 1000a, and open the control valve to expel the internal gas when the molding mold 1000 cools to between 70-75°C.

[0072] Then connect the vacuum pump to the functional interface for vacuum degassing, set the degassing temperature, turn on the vacuum pump, and operate according to the vacuum degassing temperature and vacuum degassing time required by the experiment. According to the needs of degassing quality control, an open degassing step can be added. After the vacuum degassing is completed, place the experimental cable molding sample 100 in the molding mold 1000, turn on the heating component, set the temperature-time curve according to the experimental requirements and start open degassing. After the open degassing is completed, turn off the heating component, wait until the temperature drops below 35°C, open the molding mold 1000, and take out the experimental model sample 100 for relevant test analysis.

[0073] By changing the parameters of the cross-linked polyethylene extrusion and vulcanization stages, repeating the above process, and comparing the results of the performance tests, we can find out the influence of different molding process parameters on the molding quality of the flexible joint experimental model.

[0074] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The above-described embodiments merely represent several implementation methods of the present application. 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 a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An experimental device for studying the forming process of submarine cable flexible joints, characterized in that: The experimental device includes: A molding die having a molding cavity therein, the molding die comprising at least two unit molds, each of the unit molds being provided with a unit groove, a plurality of the unit molds being used to be spliced ​​together to form the molding die, and a plurality of the unit grooves being used to collectively form the molding cavity; at least one of the unit molds being provided with a material inlet and a functional interface communicating with the molding cavity; a heating unit connected to the forming mold, and configured to transfer heat to the forming cavity of the forming mold; A monitoring unit is connected to the molding die, and the monitoring unit includes at least a temperature acquisition device and a pressure acquisition device. The temperature acquisition device is used to obtain temperature data in the molding cavity, and the pressure acquisition device is used to obtain pressure data in the molding cavity.

2. The experimental device according to claim 1, characterized in that The forming mold comprises: a first unit mold, wherein the first unit mold is provided with a first unit groove; a second unit mold, wherein the second unit mold is provided with a second unit groove; The first unit mold and the second unit mold are used to be spliced ​​together to form the molding mold, so that the first unit groove and the second unit groove together constitute the molding cavity; the second unit mold is located below the first unit mold, and the material inlet is opened in the second unit mold.

3. The experimental device according to claim 1, characterized in that The experimental device includes: A mold liner is detachably arranged on the inner wall of the molding cavity.

4. The experimental device according to claim 3, characterized in that The experimental device includes: A feeding assembly, wherein the feeding assembly includes a feeding pipe, the inner cavity of the feeding pipe is connected to the material inlet, wherein one pipe end of the feeding pipe extends from the material inlet into the molding chamber, and the pipe end of the feeding pipe extending into the molding chamber is flush with the surface of the mold lining facing the molding chamber.

5. The experimental device according to claim 1, characterized in that: The experimental device includes: A connecting component, the connecting component includes a connecting pipe and a control valve body, the inner cavity of the connecting pipe is connected to the functional interface, the connecting pipe is used to connect at least the degassing component and the pressurizing component, and the control valve body is arranged on the connecting pipe to control the opening or closing of the inner cavity of the connecting pipe.

6. The experimental device according to claim 1, characterized in that The experimental device includes a pressurizing component, which is connected to the molding cavity of the molding die through the functional interface and is used to pressurize the molding cavity; or, The experimental device includes a degassing component, which is connected to the molding cavity of the molding die through the functional interface and is used to achieve degassing of the molding cavity; or, A degassing hole communicating with the internal unit grooves of at least one of the unit molds is provided on the surface of the unit mold.

7. The experimental device according to claim 1, characterized in that The experimental device includes: A positioning component is connected to the molding die and is used to position the sample at a predetermined spatial position in the molding cavity.

8. The experimental device according to claim 1, characterized in that: The molding mold has a first position and a second position. In the molding cavity, the direction from the first position to the second position is configured as the melt filling timing direction. The material inlet is opened at the first position of the molding mold, and the functional interface is opened at the second position of the molding mold.

9. The experimental device according to claim 1, characterized in that: The heating unit is arranged outside the forming mold or in a forming cavity inside the forming mold; and / or, The heating unit includes at least one of a heating tile, a heating rod and a heating wire.

10. The experimental device according to claim 1, characterized in that: The monitoring unit includes a control device, which is control-connected to the temperature acquisition device and the heating unit.

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