EVA insulation blanket heat insulation protection method based on polyimide film

Abstract

The invention discloses an EVA insulation blanket heat insulation protection method based on a polyimide film. The method comprises the following steps that the polyimide film is cut according to the size of an insulation blanket; covering the cut polyimide film on the surface of the insulating blanket; fixing the edge of the polyimide film by adopting an insulating clamp; during hot-line work, the EVA insulation blanket covered with the polyimide film is used for insulation shielding, and the polyimide film prevents direct influence of high temperature on the EVA insulation blanket. According to the invention, the polyimide film is used as a thermal insulation material, so that the damage of high temperature to the EVA insulation blanket can be effectively prevented, and the insulation performance failure caused by hot melting and aging is avoided, thereby remarkably improving the durability and thermal insulation capability of the insulation blanket; the polyimide film is firmly attached to the surface of the EVA insulating blanket in a simple fixing mode, and it is ensured that the polyimide film does not slide or fall off in the hot-line work process.

Description

[Technical field]

[0001] The invention belongs to the technical field of electric power engineering, and in particular relates to an insulation shielding technology. [Background technology]

[0002] In the power system, the operation and maintenance of the distribution network is a key link to ensure safe and reliable power supply. With the acceleration of urbanization, the distribution network is facing increasing load pressure and environmental challenges. Therefore, live-line working of the distribution network has become an effective maintenance method. This method can not only avoid economic losses caused by power outages, but also reduce the impact on users' lives and production. However, the distribution network equipment has a complex structure and small clearance distance. When performing live-line working, the safety of operators and equipment faces severe tests. In this context, insulation shielding technology is particularly important.

[0003] Ethylene-vinyl acetate copolymer (EVA) insulation blankets have been widely used in non-stop operations in distribution networks due to their excellent insulation properties, mechanical strength and flexibility. EVA insulation blankets can effectively isolate live equipment, reduce the risk of electric shock, and ensure the safety of operators. However, EVA materials are prone to problems such as thermal melting, mechanical damage and aging under high temperature and high load conditions. These problems may lead to a rapid decline in insulation performance and premature failure of the material, which in turn poses a serious threat to the safety of live workers and power equipment.

[0004] At present, the protection of EVA insulation blankets mainly focuses on improving the performance of the material itself and coating of insulating materials. Chinese patent CN 212784522 U discloses an insulation blanket with good heat dissipation performance, including: an insulation blanket body, insulation strips, heat dissipation holes, and heat dissipation grooves; the insulation blanket body is made of insulating material; the insulation strips are square structures, located on one surface of the insulation blanket body, and are integrally constructed with the insulation blanket body; the heat dissipation holes run through the insulation strips; and the heat dissipation grooves are located between the insulation strips. Furthermore, the insulation strips and the heat dissipation grooves are arranged alternately, so that the surface of the insulation blanket body is serrated. However, these methods usually cannot effectively solve the problem of thermal aging under high temperature, and lack targeted insulation measures, which causes the EVA insulation blanket to easily overheat in a high temperature environment, thereby affecting its service life and insulation performance. Therefore, it is particularly urgent to develop an efficient insulation protection measure. [Summary of the invention]

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a thermal insulation protection method for an EVA insulation blanket based on a polyimide film, so as to solve the problem that the existing insulation blanket cannot effectively solve the thermal aging problem under high temperature and lacks targeted insulation measures, resulting in the EVA insulation blanket being easily overheated in a high temperature environment.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The heat insulation protection method of the EVA insulation blanket based on the polyimide film comprises the following steps:

[0008] Cut the polyimide film according to the size of the insulation blanket;

[0009] Covering the cut polyimide film on the surface of the insulation blanket;

[0010] An insulating clamp is used to fix the edge of the polyimide film;

[0011] When working with live wires, an EVA insulation blanket covered with a polyimide film is used for insulation shielding. The polyimide film prevents the direct impact of high temperature on the EVA insulation blanket.

[0012] Preferably, a roller tool is used to roll the polyimide film to ensure that the polyimide film is closely attached to the insulation blanket.

[0013] Preferably, after the polyimide film is covered on the surface of the insulation blanket, the edge of the polyimide film extends outward beyond the edge of the insulation blanket, and the exceeding portion is folded over to the back of the insulation blanket.

[0014] Preferably, the insulating blanket is rectangular, the polyimide film covering the surface of the insulating blanket is also rectangular, and the width of the protruding portion is 1 to 2 cm.

[0015] Preferably, the insulating clamp is provided with a concave-convex engaging surface that fits with the polyimide film to ensure that the clamp firmly clamps the film and avoids sliding.

[0016] Preferably, the thermal insulation effect of polyimide films of different thicknesses under high temperature conditions is tested by thermal insulation experiments to determine the optimal thickness range suitable for EVA insulation blankets.

[0017] Preferably, the thermal insulation test comprises the following steps:

[0018] A silicone rubber constant temperature adjustable heating device is used to simulate the high temperature working environment of the EVA insulation blanket;

[0019] Prepare polyimide film samples with thicknesses of 1mm, 2mm, 3mm, 4mm, 5mm and 6mm; collect thermal insulation effect data of polyimide films of different thicknesses at different temperature levels;

[0020] Through the above insulation experiment, in order to verify the insulation effect of polyimide films with different thicknesses, the insulation efficiency is defined as

[0021]

[0022] Where: τ is the insulation efficiency; t1 is the temperature of the polyimide film on the side in contact with the heat source; t2 is the temperature of the polyimide film on the side away from the heat source.

[0023] Preferably, a silicone rubber thermostatically adjustable heating device is used to set two temperature levels of 50°C±2°C and 60°C±2°C; and / or, the polyimide film sample is a square with a side length of 10 cm.

[0024] Preferably, the thickness of the polyimide film is 2 mm to 3 mm.

[0025] Preferably, after the operation is completed, the integrity of the polyimide film and the condition of the insulation blanket are checked. If there is wear or damage, the polyimide film is replaced in time to ensure that it continues to provide effective thermal insulation protection during the next operation.

[0026] The present invention adopts the above technical solution and has the following beneficial effects:

[0027] 1. Excellent thermal insulation performance: Polyimide film is used as the thermal insulation material, which has excellent high temperature resistance, can work stably at temperatures up to 400°C, and has extremely low dielectric loss. Polyimide film can effectively prevent high temperature damage to the EVA insulation blanket, avoid insulation failure caused by hot melting and aging, and thus significantly improve the durability and thermal insulation capacity of the insulation blanket.

[0028] 2. Extend the service life of the insulation blanket: The application of polyimide film greatly slows down the aging speed of the EVA insulation blanket in a high temperature environment and enhances its ability to resist mechanical damage. This effective thermal insulation protection can significantly extend the service life of the insulation blanket, reduce the replacement frequency, and reduce the maintenance and replacement costs, which is very valuable for practical applications in the power industry.

[0029] 3. Optimize thickness design, balance performance and operation: By optimizing the thickness of polyimide film, the thermal insulation efficiency is ensured while maintaining ease of operation. A film thickness of 2mm to 3mm can achieve an insulation efficiency of about 25%, which not only has a good thermal insulation effect, but also ensures convenient operation during construction. When the thickness increases to more than 4mm, although the thermal insulation performance is improved, the increased weight affects the flexibility of operation. Therefore, a balance between performance and operability is found through reasonable design.

[0030] 4. Easy installation and flexible operation: The polyimide film is easy to install. The edge of the polyimide film is fixed with an insulating clamp, and the polyimide film is firmly attached to the surface of the EVA insulation blanket in a simple fixing method to ensure that it does not slide or fall off during live working. This design significantly improves the installation and operation efficiency of live working, and is especially suitable for rapid on-site deployment in response to emergencies, greatly improving work efficiency and safety.

[0031] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings.

Brief Description of the Drawings

[0032] The invention will be further described below in conjunction with the accompanying drawings:

[0033] Figure 1 The temperature variation of the side away from the heat source of polyimide films with different thicknesses at 50℃ with time;

[0034] Figure 2 This is the thermal insulation efficiency diagram of polyimide films with different thicknesses at 50°C;

[0035] Figure 3 The temperature variation of the side away from the heat source of polyimide films with different thicknesses at 60°C with time;

[0036] Figure 4 This is a graph of the thermal insulation efficiency of polyimide films of different thicknesses at 60°C. [Specific implementation method]

[0037] The technical solutions of the embodiments of the present invention are explained and described below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0038] The present invention provides a heat insulation protection method for an EVA insulation blanket based on a polyimide film, which aims to solve the problems of EVA insulation blanket being easily melted, aged and having insulation performance failure in a high temperature environment. By adding a layer of polyimide film on the EVA insulation blanket, the damage to the insulation blanket caused by high temperature can be effectively delayed, and its mechanical and insulation properties can be improved, thereby improving the safety and use efficiency of live-line work.

[0039] The heat insulation protection method of the EVA insulation blanket based on the polyimide film comprises the following steps:

[0040] Cut the polyimide film according to the size of the insulation blanket;

[0041] Covering the cut polyimide film on the surface of the insulation blanket;

[0042] An insulating clamp is used to fix the edge of the polyimide film;

[0043] When working with live wires, an EVA insulation blanket covered with a polyimide film is used for insulation shielding. The polyimide film prevents the direct impact of high temperature on the EVA insulation blanket.

[0044] First, the thermal insulation material of the present invention uses polyimide film material, which is a polymer material with excellent high temperature resistance and insulation performance. Its excellent high temperature resistance and insulation performance provide better protection for EVA insulation blanket. Polyimide film material has the following characteristics:

[0045] 1) High temperature resistance: Polyimide film can withstand high temperatures of 400°C and can be used for a long time in an environment of -200°C to 300°C without significant performance changes.

[0046] 2) Excellent insulation performance: The dielectric loss of polyimide film is extremely low and it has excellent electrical insulation performance. It can maintain stable insulation properties at high temperatures, reducing the risk of insulation failure caused by high temperature.

[0047] 3) High mechanical strength: Polyimide film has high tensile strength and tear resistance, and can provide long-term and stable mechanical protection in actual use.

[0048] Therefore, the heat resistance and insulation properties of polyimide film are very suitable as thermal insulation protection materials for EVA insulation blankets, which can delay the aging and damage of insulation blankets caused by high temperature.

[0049] In order to verify the heat insulation effect of the polyimide film, a series of heat insulation tests were designed in the specific embodiment of the present invention. In the experiment, a high temperature environment was simulated by a silicone rubber constant temperature adjustable heating device to test the heat insulation effect of polyimide films of different thicknesses (1mm to 6mm).

[0050] The experimental platform includes: a silicone rubber constant temperature adjustable heating device, a polyimide film sample, a thermocouple acquisition device, a power supply, and a thermocouple acquisition data output device (computer).

[0051] Experimental purpose: To test the thermal insulation effect of polyimide films of different thicknesses under high temperature conditions and determine the optimal thickness range for EVA insulation blankets.

[0052] Experimental setup:

[0053] A silicone rubber constant temperature adjustable heating device was used to simulate the high temperature working environment of the EVA insulation blanket, and the temperature levels were set to 50℃±2℃ and 60℃±2℃ respectively.

[0054] The polyimide film was cut into squares with a length of 10 cm and a width of 10 cm, and the thicknesses of the polyimide film were made into 1 mm, 2 mm, 3 mm, 4 mm, 5 mm and 6 mm respectively, so as to facilitate the thermal insulation test of the samples.

[0055] The thermocouple collection end is placed on the other side of the polyimide film, and the temperature data is collected by computer observation until it reaches stability. The test is repeated twice, and the test data for each time is recorded.

[0056] Through the above insulation test, in order to verify the insulation effect of polyimide films with different thicknesses, its insulation efficiency can be defined as

[0057]

[0058] Where: τ is the insulation efficiency; t1 is the temperature of the polyimide film on the side in contact with the heat source; t2 is the temperature of the polyimide film on the side away from the heat source.

[0059] Test results:

[0060] The thermal insulation effect of the polyimide film thickness was studied in the experiment. The thickness was set to 1mm, 2mm, 3mm, 4mm, 5mm, and 6mm respectively. The thermal insulation test was carried out on a 50℃±2℃ constant temperature heating device until the temperature on the other side of the polyimide film reached a stable state. The test results are as follows: Figure 1 , Figure 2 As shown, it can be seen from the figure that the polyimide film has a certain heat insulation effect.

[0061] pass Figure 1 , Figure 2 It can be seen from the figure that when the thickness of the polyimide film is 1mm, the stable temperature of the side of the polyimide film away from the heat source is 44℃, and the thermal insulation efficiency of the polyimide film is 15.4% calculated by the formula; when the thickness of the polyimide film is 2mm, the stable temperature of the side of the polyimide film away from the heat source is 38.1℃, and the thermal insulation efficiency reaches 26.7%; when the thickness of the polyimide film is 3mm, the stable temperature of the side of the polyimide film away from the heat source is 37.4℃, and the thermal insulation efficiency reaches 28.1%. When the polyimide film is 4mm, the stable temperature of the other side of the polyimide film is 35.6℃, and the thermal insulation efficiency reaches 31.5%; finally, when the thickness of the polyimide film is 5mm, the stable temperature of the other side is 34.8℃, and the thermal insulation efficiency reaches nearly 33.1%. Finally, when the thickness of the polyimide film is 6mm, the stable temperature of the other side is 31℃, and the thermal insulation efficiency reaches nearly 40.4%.

[0062] In order to verify that the polyimide film has the same thermal insulation efficiency at different temperatures and thicknesses, the present invention conducted a test at 60°C ± 2°C. The results are as follows: Figure 3 , Figure 4 As shown in the figure, it can be seen that the thermal insulation efficiency of the 1mm thick polyimide film at 60°C is less than 5%, and the thermal insulation effect is extremely poor; but when the thickness is 2mm~3mm, the thermal insulation efficiency is about 25%; when the thickness is 4mm~6mm, the thermal insulation efficiency reaches more than 30%, which is similar to the result under the temperature condition of 50°C. It can be inferred that the thermal insulation efficiency of the polyimide film increases with the increase of thickness.

[0063] The test results show that as the film thickness increases, the thermal insulation efficiency increases significantly, reaching a maximum of 40.4% (6mm thickness) and a minimum of 15.4% (1mm thickness). This experiment provides an important basis for selecting the appropriate film thickness.

[0064] Since the thickness design of the polyimide film is the key to achieving a balance between thermal insulation effect and operational convenience, the thickness of the polyimide film is optimized in the present invention.

[0065] Polyimide film thickness design

[0066] In the present invention, the thickness design of the polyimide film is a key step in achieving a balance between thermal insulation effect and operational convenience. In order to ensure that the EVA insulation blanket has good thermal insulation performance in a high temperature environment while maintaining operability for live work, the present invention optimizes the thickness design of the polyimide film through experiments and multiple verifications.

[0067] Film thickness selection basis

[0068] The thickness of the polyimide film directly affects its thermal insulation performance and weight. Therefore, the present invention experimentally tests the thermal insulation effect of polyimide films of various thicknesses under different temperature conditions and their impact on operational convenience. The experimental results show that the thickness of 2mm to 3mm is the most suitable range. In this thickness range, the polyimide film can effectively isolate high temperature and reduce heat transfer, and the thermal insulation efficiency is about 25%, which means that the film can block 25% of the heat from entering the EVA insulation blanket. More importantly, the weight of the film remains within a reasonable range, and the construction workers will not feel burdened when performing live operations. The film can be easily covered and fixed on the insulation blanket, which is convenient for operators to quickly lay and adjust. Therefore, a thickness of 2mm to 3mm can achieve a balance between thermal insulation effect and convenient operation.

[0069] Increased thickness improves thermal insulation

[0070] As the thickness of the polyimide film increases, the thermal insulation performance of the film will be significantly improved. A polyimide film with a thickness of 4mm to 6mm can increase the thermal insulation efficiency to more than 30%, which means that under more extreme high temperature conditions, the heat transfer can be more effectively reduced, thereby further improving the high temperature protection capability of the insulation blanket. As the heat conduction path becomes longer, the heat will be blocked more before entering the insulation blanket, thereby slowing down the aging process of the insulation blanket material.

[0071] However, as the thickness increases, the weight of the film also increases. The weight of polyimide films of different thicknesses is shown in Table 1. While the thermal insulation performance of polyimide films with a thickness of 4mm to 6mm is improved, the increased weight makes it inconvenient for operators to install and adjust. Especially in high-altitude operations or narrow construction environments, the increase in weight will affect the flexibility of the operation, increase the burden on construction workers, and reduce work efficiency. Therefore, although thick films have better thermal insulation effects, in actual operations, overly thick films may limit construction flexibility. When using polyimide films to insulate and shield the wires during non-stop operations, the insulation blanket is inconvenient to operate due to its large thickness and heavy weight. According to the thermal insulation efficiency and quality of the corresponding thickness of the polyimide film, the best choice is a polyimide film with a thickness of 2 to 3mm to insulate the EVA insulation blanket. The thermal insulation efficiency in this range is about 25%, and the weight is relatively light. Insulating the insulation blanket with polyimide film can avoid direct contact between the insulation blanket and the conductor and prevent the insulation blanket from melting due to overheating.

[0072] Table 1 Quality of polyimide films of different thicknesses

[0073]

[0074] Installation method of polyimide film

[0075] In order to ensure the stability and effective heat insulation performance of the polyimide film on the surface of the EVA insulation blanket, the present invention provides a simple, convenient and efficient installation method. This method is intended to ensure that the film will not shift or fall off in harsh environments such as high temperature and strong wind, thereby ensuring the safety and efficiency of live-line work.

[0076] Covering Steps

[0077] During the installation process, the polyimide film must first be cut to fit different models and shapes of EVA insulation blankets. The specific covering steps are as follows:

[0078] Cutting polyimide film: According to the size and shape of the EVA insulation blanket, the polyimide film is accurately cut. When cutting, a certain edge is reserved to facilitate subsequent fixing and avoid the edge of the film from curling up.

[0079] Flat covering: Cover the cut polyimide film evenly on the surface of the EVA insulation blanket. Pay special attention to the area covered by the film, especially near the wires and other high-temperature areas. When covering, make sure the film is flat and wrinkle-free to achieve the best insulation effect. Use manual flattening or roller tools to ensure that the film fits tightly to the insulation blanket to avoid uneven insulation caused by bubbles or wrinkles.

[0080] No dead angle protection: Ensure that the polyimide film covers no dead angles, and the entire surface of the insulation blanket should be protected. If the film fails to completely cover certain parts, it may cause local overheating and insulation failure. Therefore, the coverage of the film should be carefully checked during installation to ensure that there is no leakage.

[0081] Fixing method

[0082] In order to ensure the stability of the polyimide film on the EVA insulation blanket, the present invention uses an insulating clamp for fixing, and determines the fixing position of the clamp according to the coverage of the polyimide film. The clamps should be evenly distributed on the edge of the film, especially in the area with greater force, to enhance the fixing effect; the edge of the polyimide film is inserted into the insulating clamp, and gently pressed by hand to ensure that the clamp firmly clamps the film. It should be ensured that the clamp can completely cover the edge of the film to avoid sliding. Specifically, after the polyimide film is covered on the surface of the insulation blanket, the edge of the polyimide film extends outward beyond the edge of the insulation blanket, and the excess part is folded to the back of the insulation blanket. The insulation blanket is rectangular, and the polyimide film covering the surface of the insulation blanket is also rectangular, and the width of the excess part is 1 to 2 cm. The insulation clamp is provided with a concave and convex bite surface that fits the polyimide film to ensure that the clamp firmly clamps the film and avoids sliding. Through the above-mentioned fixing method, it is ensured that the film will not shift or fall off in harsh environments such as high temperature and strong wind, and the safety and efficiency of live working are guaranteed.

[0083] Practical Application

[0084] In actual live-line operations, thermal insulation protection devices made of polyimide films have a wide range of application scenarios, including high-voltage cable maintenance and transmission line maintenance.

[0085] 1) Preparation before operation: Before live operation, workers need to select polyimide film of appropriate specifications according to the operation scenario, cover and fix it on the surface of EVA insulation blanket to ensure complete coverage of areas that may be exposed to high temperature.

[0086] 2) During live working: During live working, polyimide film can effectively prevent the direct impact of high temperature on EVA insulation blanket, prevent the degradation of insulation performance due to thermal aging, melting, etc., significantly improve the insulation blanket's tolerance in high temperature environment, extend its service life, and improve the safety and efficiency of live working in distribution network.

[0087] 3) Post-operation inspection and maintenance: After the operation is completed, the integrity of the film and the condition of the EVA insulation blanket should be checked. If there is wear or damage, the polyimide film should be replaced in time to ensure that it continues to provide effective thermal insulation protection during the next operation.

[0088] In summary, the present invention provides an efficient and reliable EVA insulation blanket insulation method through the application and optimization of polyimide film materials, which can significantly improve the high temperature resistance of the insulation blanket, extend its service life, and improve the safety and operating efficiency of live operations in distribution networks.

[0089] The above is only a specific embodiment of the invention, but the protection scope of the invention is not limited thereto. Those skilled in the art should understand that the invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the invention will be included in the scope of the claims.

Claims

1. A heat insulation protection method for an EVA insulation blanket based on a polyimide film, characterized in that: The method comprises the following steps: cutting the polyimide film according to the size of the insulation blanket; Covering the cut polyimide film on the surface of the insulation blanket; An insulating clamp is used to fix the edge of the polyimide film; When working with live wires, an EVA insulation blanket covered with a polyimide film is used for insulation shielding. The polyimide film prevents the direct impact of high temperature on the EVA insulation blanket.

2. The EVA insulation blanket heat insulation protection method according to claim 1, characterized in that: Use a roller tool to roll the polyimide film to ensure that the polyimide film fits tightly to the insulation blanket.

3. The EVA insulation blanket heat insulation protection method according to claim 1, characterized in that: After the polyimide film is covered on the surface of the insulation blanket, the edge of the polyimide film extends outwards beyond the edge of the insulation blanket, and the exceeding portion is folded to the back of the insulation blanket.

4. The EVA insulation blanket heat insulation protection method according to claim 3, characterized in that: The insulating blanket is rectangular, the polyimide film covering the surface of the insulating blanket is also rectangular, and the width of the protruding portion is 1 to 2 cm.

5. The EVA insulation blanket heat insulation protection method according to claim 1, characterized in that: The insulating clamp is provided with a concave-convex engaging surface which fits with the polyimide film, so as to ensure that the clamp firmly clamps the film and avoids sliding.

6. The EVA insulation blanket heat insulation protection method according to claim 1, characterized in that: The thermal insulation effect of polyimide films of different thicknesses under high temperature conditions was tested through thermal insulation experiments, and the optimal thickness range suitable for EVA insulation blankets was determined.

7. The EVA insulation blanket heat insulation protection method according to claim 6, characterized in that: The thermal insulation test includes the following steps: A silicone rubber constant temperature adjustable heating device is used to simulate the high temperature working environment of the EVA insulation blanket; Prepare polyimide film samples with thicknesses of 1mm, 2mm, 3mm, 4mm, 5mm and 6mm; Collect thermal insulation effect data of polyimide films of different thicknesses at different temperature levels; Through the above insulation experiment, in order to verify the insulation effect of polyimide films with different thicknesses, the insulation efficiency is defined as τ= t1-t2 ×100% t1 Where: τ is the insulation efficiency; t1 is the temperature of the polyimide film on the side in contact with the heat source; t2 is the temperature of the polyimide film on the side away from the heat source.

8. The EVA insulation blanket heat insulation protection method according to claim 7, characterized in that: A silicone rubber thermostatically adjustable heating device is used to set two temperature levels of 50°C±2°C and 60°C±2°C respectively; and / or, the polyimide film sample is a square with a side length of 10 cm.

9. The EVA insulation blanket heat insulation protection method according to claim 1, characterized in that: The thickness of the polyimide film is 2 mm to 3 mm.

10. The EVA insulation blanket heat insulation protection method according to claim 1, characterized in that: After the operation is completed, check the integrity of the polyimide film and the condition of the insulation blanket. If there is wear or damage, replace the polyimide film in time to ensure that it continues to provide effective thermal insulation protection during the next operation.

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