An experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device and method

Abstract

The present invention provides an experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device and method, the device includes an extruder, a heating solenoid and an injection mold, the injection mold is arranged in the heating solenoid, the extruder squeezes raw materials into the injection mold, the injection mold includes a head, an air outlet pipe, an air outlet, a first injection channel, a second injection channel, a bevel body and a cylinder, the head is installed at the open end of the cylinder, the cylindrical bevel is arranged in the cylinder, the air outlet pipe and the first injection channel are arranged just above the cylinder, the air outlet and the second injection channel are arranged just below the cylinder, and the cylinder is horizontally placed on a bracket. The present invention can independently prepare the sample studied in the experiment, and study the influence of variables such as extrusion rate, extrusion temperature and reaction force cone inclination on the electrical characteristics of the interface, so as to correctly guide the design of the molding mold and the selection of extrusion parameters, improve the quality of the joint products actually produced, and improve production efficiency.

Description

Technical Field

[0001] The invention belongs to the field of injection molding equipment, and in particular relates to an experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device and method. Background Art

[0002] Polyethylene insulated high-voltage DC cable is a submarine power cable, mainly used for power grid connection between islands and the mainland or between islands, between land and offshore wind farms, and between offshore drilling platforms. The length of a single cable is limited by the cable manufacturing equipment. When the length of a single cable cannot meet the use requirements, multiple cables can be connected with flexible joints until the use length requirements are met.

[0003] The preparation of flexible joints is mainly achieved through injection molding. During the preparation, an extruder is used to extrude the cross-linked polyethylene base material and fill it into the molding mold. During the preparation process, the selected molding mold, the extrusion rate and extrusion temperature of the extruder will have a significant impact on the quality of the flexible joint.

[0004] The production of submarine cable flexible joints is to inject the insulation material into the submarine cable body insulation after the conductors are connected in the factory, accompanied by the heating cross-linking process. The anatomical study of a certain number of injection-molded flexible joints found that the insulation layer of the joint has three forms in a certain sense: body insulation, recovery insulation and transition zone insulation.

[0005] There is an XLPE-XLPE interface area with a width of about 10mm between the XLPE insulation area of ​​the joint restoration and the XLPE insulation area of ​​the main body of the injection-molded flexible joint. According to the data provided by relevant domestic enterprises, the location where the high-voltage cable injection-molded flexible joint is damaged during the trial operation or factory test is mostly close to this interface area. Since the overall size of the reaction force cone is relatively long, the interface area extends over a wide range. Since the internal insulation quality of the high-voltage submarine cable flexible joint determines the performance of the entire flexible joint, it is extremely important to study the formation mechanism of the above-mentioned internal microstructure. Since the interface samples of the insulation layer of the high-voltage XLPE cable flexible joint studied in the current experiment are obtained by cutting the cables provided by the factory, it is impossible to study the influence of variables such as extrusion rate, extrusion temperature and reaction force cone inclination on the electrical properties of the XLPE-XLPE interface. Therefore, it is impossible to correctly guide the design of the molding die and the selection of extrusion parameters, resulting in low preparation efficiency of the flexible joint in actual production, low product quality and instability. Summary of the invention

[0006] In view of this, the present invention aims to propose an experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device and method, which can independently prepare the high-voltage XLPE cable flexible joint insulation layer interface sample studied in the experiment, and can study the influence of variables such as extrusion rate, extrusion temperature and reaction force cone inclination on the XLPE-XLPE interface electrical properties, so as to correctly guide the design of the molding die and the selection of extrusion parameters, thereby improving the preparation efficiency of the flexible joint in actual production, and the product quality is high and the performance is stable.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] The invention discloses an experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device, comprising an extruder, a heating solenoid and an injection mold, wherein the injection mold is arranged in the heating solenoid, the extruder is arranged outside the heating solenoid and the injection mold, the extruder squeezes raw materials into the injection mold, the injection mold comprises a head, an air outlet pipe, a bracket, an air outlet, a first injection channel, a second injection channel, a bevel body and a cylinder, one end of the cylinder is an open end, and the other end is a closed end, the head is installed at the open end of the cylinder, the bevel body is arranged in the cylinder, and the two ends of the bevel body are respectively against the cylinder and the head, the air outlet pipe and the first injection channel are arranged directly above the cylinder and communicate with the cylinder, the air outlet and the second injection channel are arranged directly below the cylinder and communicate with the cylinder, the axis of the air outlet pipe is arranged perpendicularly to the axis of the head, the air outlet pipe and the second injection channel are arranged symmetrically with the central axis of the cylinder, and the cylinder is horizontally placed on the bracket.

[0009] Furthermore, the bevel body is a structure formed by cutting from one end to the other end of the cylinder with an inclined section, the angle between the inclined section and the horizontal plane is 10°-45°, and the length of the bevel body is 280 mm.

[0010] Furthermore, the heating coil and the cylinder are seamlessly nested.

[0011] Furthermore, both injection channels are cylindrical channels.

[0012] Furthermore, the length of the cylinder is 300 mm.

[0013] Furthermore, the device also includes two mold pads, which are placed at both ends of the bracket. The upper surfaces of the two mold pads are both arc-shaped surfaces, and the two ends of the cylinder are respectively seated on the two arc-shaped surfaces, and the arc-shaped surfaces are adapted to the arc-shaped surfaces of the cylinder.

[0014] Furthermore, the extruder includes a filling bin, an extrusion screw and a heating head, wherein the filling bin is arranged at one end of the extrusion screw, the heating head is arranged at the other end of the extrusion screw, and the heating head is connected to the injection channel.

[0015] The method for preparing the insulating layer interface of a high-voltage XLPE cable flexible joint using the above device specifically comprises the following steps:

[0016] Step 1, preparation of the polyethylene slope: firstly put the slope body into the cylinder, then connect the cylinder and the head, make the two ends of the slope body lean against the cylinder and the head respectively, seal the second injection channel and the air outlet, then put the injection mold equipped with the slope body on the bracket, connect the extruder and the first injection channel, and finally inject polyethylene into the injection mold through the extruder to prepare the polyethylene slope;

[0017] Step 2, after the polyethylene slope in step 1 is prepared, the interface is prepared: disconnect the extruder and the first injection channel, turn the injection mold 180 degrees, remove the outlet pipe and connect it to the outlet, and seal the opening of the first injection channel and the removed outlet pipe, open the head, take out the inclined body, and then connect the head to the cylinder, place the injection mold on the bracket, connect the extruder 1 and the second injection channel, and the extruder injects polyethylene into the injection mold until the preparation of the interface of the high-voltage XLPE cable flexible joint insulation layer is completed.

[0018] Compared with the prior art, the device and method for simulating the interface of the insulating layer of a high-voltage XLPE cable flexible joint for experiment described in the present invention have the following advantages:

[0019] 1. The present application is an experimental injection molding device. When the device is used to prepare the XLPE-XLPE interface, the polyethylene slope is first prepared, and the steel cylindrical slope is placed in a cylindrical mold so that the two ends of the slope are respectively against the two bottoms of the cylinder, and then the injection mold is placed in a heating solenoid, and the extruder and the injection mold are connected. The polyethylene is squeezed into the cylinder through the injection channel to form a slope; after the slope is prepared, the interface is prepared by secondary injection of polyethylene; in the experiment, the extrusion rate, extrusion temperature, inclination of the slope and other parameters can be changed to prepare the XLPE-XLPE interface, and the design of the actual molding mold is optimized by studying the electrical characteristics of the interface under different extrusion parameters, thereby improving the quality of the joint products actually produced, improving production efficiency, and saving production costs.

[0020] 2. The present application has a simple structure, is easy to operate, has a small size and a low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 A schematic diagram of the three-dimensional structure of an experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device according to an embodiment of the present invention;

[0023] Figure 2 This is a front view of an experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device according to an embodiment of the present invention;

[0024] Figure 3 for Figure 1 AA section view;

[0025] Figure 4 is the front view of a certain inclined plane;

[0026] Figure 5 It is a side view of a certain inclined plane;

[0027] Figure 6 This is a top view of a certain type of inclined plane.

[0028] Description of reference numerals:

[0029] 1-extruder, 1-1-filling bin, 1-2-extrusion screw, 1-3-heating head, 2-heating solenoid, 3-injection mold, 4-first injection channel, 5-end, 6-air outlet pipe, 7-cylinder, 8-bracket, 9-mold pad, 10-bevel, 11-air outlet, 12-second injection channel. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0031] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0032] like Figure 1-Figure 3As shown, an experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device includes an extruder 1, a heating solenoid 2 and an injection mold 3, wherein the injection mold 3 is arranged in the heating solenoid 2, the extruder 1 is arranged outside the heating solenoid 2 and the injection mold 3, the extruder 1 squeezes the raw material into the injection mold 3, the injection mold 3 includes a head 5, an air outlet pipe 6, a bracket 8, an air outlet 11, a first injection channel 4, a second injection channel 12, a bevel 10 and a cylinder 7, one end of the cylinder 7 is an open end, and the other end is a closed end, the head 5 It is installed at the open end of the cylinder 7, the inclined body 10 is arranged in the cylinder 7, and the two ends of the inclined body 10 are respectively against the cylinder 7 and the head 5, the air outlet pipe 6 and the first injection channel 4 are arranged just above the cylinder 7 and communicate with the cylinder 7, the air outlet 11 and the second injection channel 12 are arranged just below the cylinder 7 and communicate with the cylinder 7, the axis of the air outlet pipe 6 is arranged perpendicular to the axis of the head 5, the air outlet pipe 6 and the second injection channel 12 are symmetrically arranged with the central axis of the cylinder 7, and the cylinder 7 is horizontally placed on the bracket 8, and the length direction is parallel to the length direction of the bracket 8.

[0033] The bevel body 10 is a structure formed by cutting from one end of a cylinder to the other end with an inclined section, the angle between the inclined section and the horizontal plane is 10°-45°, and the length of the bevel body 10 is 280 mm. By changing the inclination of the inclined surface of the cylindrical bevel body 10, the influence of different slopes of the reaction force cone at different positions of the actual flexible joint on the interface is simulated. Figure 3 The inclined plane 10 is shown in one of the inclinations. Figure 4-Figure 6 Another type of inclined plane is given, which is cut along the diagonal direction, cutting the complete cylinder into two equally sized inclined planes that are symmetrical along the axis of the cylinder.

[0034] The heating solenoid 2 and the cylinder 7 are seamlessly nested structures, with good heating effect and firm installation.

[0035] Both injection molding channels are cylindrical channels, and such a design allows the polyethylene to flow evenly into the cylinder 7 .

[0036] The length of the cylinder 7 is 300 mm. Through actual cable samples and related simulation analysis, it is concluded that the interface of this length is the most practically effective.

[0037] The device also includes two mold pads 9, which are placed at both ends of the bracket 8. The upper surfaces of the two mold pads 9 are both arc-shaped surfaces, and the two ends of the cylinder 7 are respectively seated on the two arc-shaped surfaces, and the arc-shaped surfaces are adapted to the arc-shaped surfaces of the cylinder 7. Such a design can ensure the overall stability of the injection mold 3 during the experiment.

[0038] The extruder 1 includes a filling bin 1-1, an extrusion screw 1-2 and a heating head 1-3, wherein the filling bin 1-1 is arranged at one end of the extrusion screw 1-2, the heating head 1-3 is arranged at the other end of the extrusion screw 1-2, and the heating head 1-3 is connected to the injection channel.

[0039] The high-voltage XLPE cable flexible joint mentioned in this application is an existing joint.

[0040] The method for preparing the insulating layer interface of a high-voltage XLPE cable flexible joint using the above device specifically comprises the following steps:

[0041] Step 1, preparation of polyethylene slope: first put the sloped body 10 into the cylinder 7, then connect the cylinder 7 and the head 5, so that the two ends of the sloped body 10 are respectively against the cylinder 7 and the head 5, the second injection channel 12 and the air outlet 11 are sealed, and then the injection mold 3 equipped with the sloped body 10 is placed on the bracket 8, the extruder 1 and the first injection channel 4 are connected, and the extruder 1 is started, and polyethylene is filled into the extruder 1 from the filling bin 1-1 of the extruder 1, so that the polyethylene enters the first injection channel 4 through the extrusion screw 1-2 and the heating head 1-3 of the extruder 1, and then the polyethylene is injected into the cylinder 7 of the injection mold 3 to prepare the polyethylene slope. When the polyethylene is squeezed in, a gap is left between the cylinder 7 and the polyethylene to ensure smooth gas discharge during the preparation process;

[0042] Step 2, after the polyethylene slope in step 1 is prepared, the interface is prepared: disconnect the extruder 1 and the first injection channel 4, turn the injection mold 3 180 degrees, remove the outlet pipe 6 and connect it to the outlet 11, and seal the first injection channel 4 and the opening where the outlet pipe 6 is removed, open the head 5, take out the inclined body 10, and then connect the head 5 to the cylinder 7, place the injection mold 3 on the bracket 8, connect the extruder 1 and the second injection channel 12, and the extruder 1 injects polyethylene into the injection mold 3 until the preparation of the interface of the high-voltage XLPE cable flexible joint insulation layer is completed.

[0043] After the interface preparation of the present application is completed, the advantages and disadvantages of the electrical properties of the XLPE-XLPE interface under different extrusion parameters are analyzed to guide the setting of extrusion parameters and optimize the design of the actual mold.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device, characterized in that: The invention comprises an extruder (1), a heating solenoid (2) and an injection mold (3), wherein the injection mold (3) is arranged inside the heating solenoid (2), the extruder (1) is arranged outside the heating solenoid (2) and the injection mold (3), the extruder (1) squeezes raw materials into the injection mold (3), the injection mold (3) comprises a sealing head (5), an air outlet pipe (6), a bracket (8), an air outlet (11), a first injection channel (4), a second injection channel (12), a bevel (10) and a cylinder (7), one end of the cylinder (7) is an open end and the other end is a closed end, the sealing head (5) is installed on the cylinder (7) ), the inclined surface (10) is arranged in the cylinder (7), and the two ends of the inclined surface (10) are respectively pressed against the cylinder (7) and the head (5), the air outlet pipe (6) and the first injection channel (4) are arranged just above the cylinder (7) and communicate with the cylinder (7), the air outlet (11) and the second injection channel (12) are arranged just below the cylinder (7) and communicate with the cylinder (7), the axis of the air outlet pipe (6) is arranged perpendicular to the axis of the head (5), the air outlet pipe (6) and the second injection channel (12) are arranged symmetrically with respect to the central axis of the cylinder (7), and the cylinder (7) is horizontally placed on the bracket (8); The bevel body (10) is a structure formed by cutting from one end of a cylinder to the other end with an inclined section; the angle between the inclined section and the horizontal plane is 10°-45°, and the length of the bevel body (10) is 280 mm; The length of the cylinder (7) is 300 mm.

2. The device for simulating the interface of the insulating layer of a high-voltage XLPE cable flexible joint for experiment according to claim 1, characterized in that: The heating coil (2) and the cylinder (7) are seamlessly nested structures.

3. The device for simulating the interface of the insulating layer of a high-voltage XLPE cable flexible joint for experiment according to claim 1, characterized in that: Both injection channels are cylindrical channels.

4. An experimental high-voltage XLPE cable flexible joint insulation layer interface simulation device according to any one of claims 1 to 3, characterized in that: The device also includes two mold pads (9), which are placed at the two ends of the bracket (8). The upper surfaces of the two mold pads (9) are both arc-shaped surfaces. The two ends of the cylinder (7) are respectively seated on the two arc-shaped surfaces, and the arc-shaped surfaces are adapted to the arc-shaped surfaces of the cylinder (7).

5. The device for simulating the interface of the insulating layer of a high-voltage XLPE cable flexible joint for experiment according to claim 1, characterized in that: The extruder (1) comprises a filling bin (1-1), an extrusion screw (1-2) and a heating head (1-3); the filling bin (1-1) is arranged at one end of the extrusion screw (1-2); the heating head (1-3) is arranged at the other end of the extrusion screw (1-2); and the heating head (1-3) is connected to an injection channel.

6. A method for preparing the interface of the insulation layer of a high-voltage XLPE cable flexible joint using an experimental high-voltage XLPE cable flexible joint insulation layer simulation device according to any one of claims 1 to 3, characterized in that: The specific steps include: Step 1, preparation of the polyethylene bevel: firstly, the bevel body (10) is placed in the cylinder (7), and then the cylinder (7) and the end cap (5) are connected so that the two ends of the bevel body (10) are respectively pressed against the cylinder (7) and the end cap (5), and the second injection channel (12) and the air outlet (11) are sealed, and then the injection mold (3) equipped with the bevel body (10) is placed on the bracket (8), and the extruder (1) and the first injection channel (4) are connected, and finally the extruder (1) injects polyethylene into the injection mold (3) to prepare the polyethylene bevel; Step 2, after the polyethylene slope in step 1 is prepared, the interface is prepared: disconnect the extruder (1) and the first injection channel (4), flip the injection mold (3) 180 degrees, remove the outlet pipe (6) and connect it to the outlet (11), and seal the first injection channel (4) and the opening where the outlet pipe (6) is removed, open the head (5), take out the inclined body (10), and then connect the head (5) to the cylinder (7), place the injection mold (3) on the bracket (8), connect the extruder 1 and the second injection channel (12), and inject polyethylene into the injection mold (3) by the extruder (1) until the preparation of the interface of the high-voltage XLPE cable flexible joint insulation layer is completed.

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