Fuseable Noise Reduction Plate for UHV Large Oil-Filled Equipment, Preparation Method and Sound Insulation Enclosure

Abstract

The present invention discloses a fusible noise reduction board for extra-high voltage large oil-filled equipment, a preparation method and a sound insulation cover. The fusible noise reduction board includes: a grid board, a frame, a substrate, and a plastic film; the grid board is connected to the frame, a part of the substrate is embedded in the grid board, and a part covers the grid board; the plastic film wraps the frame to form a closed cavity with the grid board embedded in the substrate; and a surface coating is sprayed on the plastic film and the substrate covering the grid board; the plastic film faces the sound source and forms a resonance system with the air layer in the cavity when encountering sound. The present invention enables the fusible noise reduction board to have the functions of high-temperature shedding, sound insulation and sound absorption, improves the noise reduction ability of the sound insulation cover, and at the same time has excellent load-bearing performance.

Description

Technical Field

[0001] The present invention relates to the technical field of fire prevention and control for extra-high voltage large oil-filled equipment, and specifically to a fusible noise reduction plate for extra-high voltage large oil-filled equipment, a preparation method thereof, and a sound insulation cover. Background Technique

[0002] To meet the noise reduction and fire-fighting emergency requirements of extra-high voltage large oil-filled equipment (converter transformer), a sound insulation cover is usually provided around it, and a high-temperature shedding structure is provided on the top cover of the sound insulation cover, so as to ensure that the top cover of the sound insulation cover has an automatic opening function during a fire, providing favorable conditions for external fire-fighting to effectively act on the fire source. Currently, the main high-temperature shedding scheme for converter transformers is the fusible noise reduction plate scheme.

[0003] The fusible noise reduction plate scheme uses a noise reduction plate that can fuse itself as the main body of noise reduction. The fusible noise reduction plate is polymerized from sand grains and a polymer adhesive. When a fire occurs in the equipment, the noise reduction plate melts itself into small fragments and falls off under the action of high temperature, enabling the top cover of the sound insulation cover to open, thereby providing a way for external fire-fighting.

[0004] However, in the fusible noise reduction plate scheme, due to material reasons, the fusible noise reduction plate is relatively fragile, has poor load-bearing capacity, is afraid of water, and is easily damaged by external forces, such as bumps and scratches at the engineering site, which can easily damage the noise reduction plate. For another example, the strength of the fusible noise reduction plate drops sharply after being drenched in rain, resulting in deformation or even self-dropping problems. For example, in actual use, there have been incidents of water seepage, dropping, or cracking of the fusible noise reduction plate during operation in converter stations, making it difficult to meet the actual operation requirements.

[0005] In order to improve the surface protection ability of the fusible noise reduction plate, a polyurea coating is sprayed on the surface of the fusible noise reduction plate, solving the problems of bumps, scratches, and waterproofing. As in the prior art, the invention patent with the publication number CN115007427A discloses a treatment method for spraying polyurea on a substrate and the produced substrate. The produced substrate includes a substrate layer, an interface treatment layer, a sealing layer, and a polyurea layer; the interface treatment layer is on the substrate layer, the sealing layer is on the interface treatment layer, and the polyurea layer is on the sealing layer. However, in this patent, by spraying polyurea on the substrate, the waterproof performance of the substrate surface is improved. When applied to the sound insulation board on the top and / or facade of the BOX-IN, the polyurea coating on the surface makes the fusible noise reduction plate lose its sound absorption function, and it can only achieve sound insulation and noise reduction based on its own material, unable to absorb sound, and has poor noise reduction ability.

[0006] In addition, after the noise reduction plate on the top cover of the sound insulation cover is installed, to ensure safety, it is necessary to mark the load-bearing area and non-load-bearing area on the top cover, and at the same time add a fall prevention net to avoid safety accidents such as falling when in-station maintenance personnel carry out maintenance operations on the non-load-bearing area. The load-bearing performance of the fusible noise reduction plate still cannot meet the requirements of engineering applications. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to solve the problems of poor noise reduction ability and low load-bearing capacity of the current detachable noise reduction board.

[0008] To solve the above technical problems, the present invention provides the following technical solutions:

[0009] A fusing noise reduction board for extra-high voltage large oil-filled equipment, comprising: a grid plate 631, a frame 632, a substrate 633, and a plastic film 634;

[0010] The grid plate 631 is connected to the frame 632, and a part of the substrate 633 is embedded in the grid plate 631 and a part covers the grid plate 631;

[0011] The plastic film 634 wraps the frame 632 to form a closed cavity 637 with the grid plate 631 embedded in the substrate 633; and a surface coating is sprayed on the plastic film 634 and the substrate 633 covering the grid plate 631.

[0012] The plastic film 634 faces the sound source and forms a resonance system with the air layer in the cavity 637 when encountering sound.

[0013] In an embodiment of the present invention, the surface coating is airtight and waterproof, and includes an outer surface coating 635 and an inner surface coating 636; the inner surface coating 636 is located on the plastic film 634, and the outer surface coating 635 is located on the substrate 633 covering the grid plate 631.

[0014] In an embodiment of the present invention, the material of the airtight and waterproof surface coating is polyurea.

[0015] In an embodiment of the present invention, the substrate 633 includes a first layer of sand plate 6331 and a second layer of sand plate 6332; the first layer of sand plate 6331 is embedded in the grid plate 631, and the second layer of sand plate 6332 covers the grid plate 631.

[0016] In an embodiment of the present invention, the first layer of sand plate 6331 is made of coarse sand, and the second layer of sand plate 6332 is made of fine sand.

[0017] In an embodiment of the present invention, pits are provided on the second layer of sand plate 6332, and a part of the first layer of sand plate 6331 is embedded in the pits.

[0018] In an embodiment of the present invention, the frame 632 is a groove structure frame, including a first groove, and the grid plate 631 is fixedly located in the first groove.

[0019] In an embodiment of the present invention, the frame 632 includes a second groove; the second groove and the first layer of sand plate 6331 serve as the framework of the cavity 637, and together with the plastic film 634, form a closed cavity 637.

[0020] In an embodiment of the present invention, during use, when sound waves are incident on the inner surface coating 636, the inner surface coating 636 vibrates under the excitation of the sound wave pressure. The plastic film 634 and the inner surface coating 636 undergo bending deformation, and frictional losses occur inside them, consuming sound energy; at the same time, the resonance system dissipates the resonant sound waves, and, after the sound waves outside the remaining resonant frequencies enter the cavity 637, they generate friction with the pores in the substrate 633 to dissipate sound energy.

[0021] The present invention also provides a preparation method for a fusing noise reduction plate for extra-high voltage large oil-filled equipment, wherein the preparation method of the substrate 633 includes:

[0022] Take quartz sand grains of 60 - 100 mesh and stir them evenly with an adhesive, then pour them into the rectangular mold 10; after compacting and leveling them in the rectangular mold 10, use a roller mold 20 with protrusions to roll them, so as to form a pit on the leveling surface; after compacting and forming, send them into an oven for the first baking process to form the second layer of sand plate 6332;

[0023] Take aeolian sand of 20 - 40 mesh and stir it evenly with an adhesive;

[0024] Align the grid plate 631 and place it on the rectangular mold 10, pour the evenly stirred aeolian sand into the grid plate 631, and use a rolling mold 30 to roll the aeolian sand in each grid until it becomes a flat plate to form the first layer of sand plate 6331; send it into an oven for the second baking process to cure and form;

[0025] After cooling, demold the rectangular mold at room temperature.

[0026] In an embodiment of the present invention, the baking temperature and baking time of the second baking process are greater than those of the first baking process.

[0027] In an embodiment of the present invention, the baking temperature of the first baking process is 80 - 100 °C, and the baking time is 18 - 25 minutes; the baking temperature of the second baking process is 120 - 170 °C, and the baking time is 50 - 70 minutes.

[0028] In an embodiment of the present invention, the spraying method of the surface coating of the fusing noise reduction plate includes:

[0029] For the already assembled grid plate 631, frame 632, and substrate 633, with the second groove in the frame 632 facing upward, wrap the plastic film 634 around the outer surface of the entire frame 632;

[0030] The polyurea is sprayed on the plastic film 634 by a spraying device to form an inner surface coating 636;

[0031] Turn it over so that the second groove faces downward, and spray polyurea on the substrate 633 covering the grid plate 631 to form an outer surface coating 635.

[0032] In an embodiment of the present invention, when designing the spacing between two adjacent protrusions on the drum mold 20, the grid size on the grid plate 631 is considered.

[0033] In an embodiment of the present invention, when the drum mold 20 is in use, the formed pits are within the squares of the grid plate 631.

[0034] In an embodiment of the present invention, the length of the drum on the rolling mold 30 matches the length of the square of the grid plate 631.

[0035] In an embodiment of the present invention, when in use, the spacing between two adjacent drums on the rolling mold 30 is engaged on the grid board shared by two squares.

[0036] The present invention also provides a sound insulation cover, and the top cover of the sound insulation cover uses the fuseable noise reduction plate for extra-high voltage large oil-filled equipment described above.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] First, the present invention combines thin-film resonance sound absorption and porous sound absorption, enabling the detachable noise reduction plate to have sound absorption performance. In the past, the fuseable noise reduction plate only had sound insulation performance. Although there was sound absorption by the sound absorber inside the sound insulation cover, due to the small sound absorption area inside the sound insulation cover, the reverberant sound inside the sound insulation cover was relatively large. On the one hand, it deteriorated the sound environment for personnel to work inside the sound insulation cover. On the other hand, the increase in the reverberant sound inside the sound insulation cover offset the sound insulation ability of the sound insulation cover, resulting in poor overall noise reduction performance of the sound insulation cover. The present invention makes full use of the elastic characteristics of the polyurea coating film and the porous sound absorption characteristics of the particulate material, enabling the fuseable noise reduction plate to have excellent sound absorption performance, reducing the reverberant sound inside the sound insulation cover, and improving the noise reduction ability of the sound insulation cover.

[0039] Second, compared with the conventional fusing noise reduction board, the detachable noise reduction board of the present invention has better load-bearing performance, avoiding the risk of falling when personnel perform maintenance operations above it. More maintenance equipment and tools can be placed above it. At the same time, there is no need to mark the load-bearing area and non-load-bearing area, nor to add a fall prevention net, significantly improving the on-site construction efficiency and reducing the risk of personnel maintenance. The conventional fusing noise reduction board adopts a structural form of a 20-mm-thick fusing particle board combined with a support skeleton. The support skeleton is made of a 1.5-mm-thick galvanized steel plate folded into a channel shape of 15 mm × 30 mm × 15 mm, and both ends are connected to the outer frame skeleton. In order not to let the dense skeleton affect the high-temperature detachment of the fusing particle board, the skeleton spacing is arranged at 300 mm to 600 mm. The width of the grid formed by the skeleton and the outer frame is the same as the skeleton spacing of 300 mm to 600 mm, and the grid length is 600 mm to 750 mm. The limit value of its load-bearing capacity generally does not exceed 500 kg / m². With the influence of sunlight exposure aging, rain, etc. on the fusing particle board, its load-bearing performance drops significantly and it sags and deforms downward. There is not only a risk of falling when someone works above it, but also a risk of the fusing particle board itself falling, with great potential hazards. Although some solutions adopt the method of spraying a polyurea coating on the surface to improve the damage resistance and aging performance of the fusing noise reduction board, the load-bearing capacity still cannot be improved due to structural reasons. Especially, the load-bearing capacity is the worst within the interval of the skeleton, and the area above the skeleton is the second. In order to prevent personnel from falling when standing above or excessive weight from damaging the fusing noise reduction board, the fusing noise reduction board on the top cover of the sound insulation cover is marked, the load-bearing area and non-load-bearing area are divided, and a fall prevention net is added, increasing the construction process and significantly affecting the commissioning efficiency of the newly built station.

[0040] Third, the present invention also proposes to use a separating rolling die with a limited pressing depth to compact the particle mortar and use a plastic film as the support for spraying polyurea, which not only ensures the feasibility of the production process but also simplifies the production process and improves the production efficiency. The substrate adopts a two-layer structure design. The first layer of sand board serves as the sound insulation layer and is located on the outer layer, mixed with quartz sand grains. The second layer of sand board serves as the sound absorption layer and is located on the inner layer, using aeolian sand, enabling it to have both sound insulation and sound absorption functions at the same time. The substrate is compacted and baked in two steps during preparation. The first layer of sand board needs to be baked at a low temperature for a short time first to carry out an incomplete chemical reaction, and at the same time, it also reserves sufficient reaction conditions for good fusion after adding the second layer of sand board. Then, the second layer of sand board is formed and the whole is baked. In addition, before baking the inner surface of the first layer of sand board, pits need to be pressed out to ensure good bonding between the two layers of sand board.

[0041] The sprayed polyurea on the outer surface plays a role in enhancing sound insulation. The sprayed polyurea forms an airtight closed cavity in the inner cavity of the entire fusible noise reduction plate. The polyurea on the inner surface is in the form of a relatively thin film, which plays a role in thin-film sound absorption. Description of the Drawings

[0042] Figure 1 Schematic diagram of a fusible noise reduction plate for extra-high voltage large oil-filled equipment according to an embodiment of the present invention.

[0043] Figure 2 Schematic diagram of a grid plate according to an embodiment of the present invention.

[0044] Figure 3 Schematic diagram of a grid plate and a substrate according to an embodiment of the present invention.

[0045] Figure 4 Schematic diagram of a rectangular mold according to an embodiment of the present invention.

[0046] Figure 5 Schematic diagram of a drum mold according to an embodiment of the present invention.

[0047] Figure 6 Schematic diagram of a pit according to an embodiment of the present invention.

[0048] Figure 7 Schematic diagram of the alignment of a rectangular mold and a grid plate according to an embodiment of the present invention.

[0049] Figure 8 Schematic diagram of a rolling mold according to an embodiment of the present invention.

[0050] Figure 9 Schematic diagram of a rolling mold, a substrate and a grid plate according to an embodiment of the present invention.

[0051] Figure 10 Actual photo of the structure of Comparative Example 1 in the impedance tube test according to an embodiment of the present invention.

[0052] Figure 11 Actual photo of the structure of Comparative Example 2 in the impedance tube test according to an embodiment of the present invention.

[0053] Figure 12 Actual photo of the structure of the present invention in the impedance tube test according to an embodiment of the present invention.

[0054] Figure 13 Impedance tube sound absorption curve of the structure of Comparative Example 1 according to an embodiment of the present invention.

[0055] Figure 14 Impedance tube sound absorption curve of the structure of Comparative Example 2 according to an embodiment of the present invention.

[0056] Figure 15 Impedance tube sound absorption curve of the structure of the present invention according to an embodiment of the present invention.

[0057] Figure 16 The impedance tube sound absorption curves of the invention structure of the embodiment of the present invention, the structure of Comparative Example 1, and the structure of Comparative Example 2.

[0058] Figure 17 The actual picture of the reverberation sound absorption test sample of the invention structure of the embodiment of the present invention.

[0059] Figure 18 The reverberation sound absorption curve of the invention structure of the embodiment of the present invention.

[0060] Figure 19 The schematic diagram of the sound insulation cover of the embodiment of the present invention. Detailed implementation manners

[0061] To facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings of the specification.

[0062] The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0063] Please refer to Figures 1 to 3 As shown, this embodiment provides a fuseable noise reduction plate for extra-high voltage large oil-filled equipment, including a grid plate 631, a frame 632, a substrate 633, and a plastic film 634. The grid plate 631 is connected to the frame 632. The substrate 633 is partially embedded in the grid plate 631 and partially covers the grid plate 631. The plastic film 634 wraps the frame 632, so as to form a closed cavity 637 with the grid plate 631 embedded in the substrate 633. On the plastic film 634 and the substrate 633 covering the grid plate 631, an airtight and waterproof surface coating is sprayed, so as to form a closed air layer inside the fuseable noise reduction plate. The plastic film 634 faces the sound source, and when encountering sound, it forms a resonance system with the air layer, playing the role of film resonance sound absorption.

[0064] In this embodiment, the surface coating includes an outer surface coating 635 and an inner surface coating 636. The inner surface coating 636 is located on the plastic film 634, and the outer surface coating 635 is located on the substrate 633 covering the grid plate 631. More specifically, the material of the airtight and waterproof surface coating is polyurea.

[0065] Please refer to Figure 2As shown, in this embodiment, the grid plate 631 is made by welding flat steel and twist steel bars. The thickness of the flat steel is 2 - 4 mm, the width is 25 - 50 mm, and the diameter of the twist steel bars is 2 - 5 mm. The flat steel and the twist steel bars are welded into a grid shape, and the specifications of the grid are that the length ranges from 120 to 160 mm and the width ranges from 120 to 160 mm. After the grid plate 631 is welded and formed, it is subjected to hot-dip galvanizing treatment on the surface to improve the anti-corrosion performance.

[0066] In this embodiment, the grid specifications of the grid plate 631 are 150 mm × 150 mm, which facilitates the easier fusing of the substrate 633 and can also ensure the support safety for the operators standing above it. At the same time, the support structure using steel grating effectively improves the load-bearing performance of the noise reduction plate, which can meet the uniform load of 4 kN / ㎡, and can also meet the concentrated load of 4 kN within the range of 0.1 m wide × 0.25 m long.

[0067] In this embodiment, the frame 632 is a groove structure frame, including a first groove and a second groove. During production, it is first made of galvanized steel plate, bent into two groove shapes first, and then welded and formed. Among them, the grid plate 631 is fixedly located in the first groove. During welding, full welding is used at the connection parts between the frames 632 and between the frame 632 and the grid plate 631 to ensure airtightness.

[0068] In this embodiment, the substrate 633 is polymerized from about 95% sand grains and about 5% polymer adhesives, and the total thickness is 18 - 22 mm. In this embodiment, the substrate 633 includes a first sand plate 6331 and a second sand plate 6332.

[0069] Among them, the first sand plate 6331 is embedded in the grid plate 631, and the second sand plate 6332 serves as the outer surface of the detachable noise reduction plate, which can ensure a flat surface. The second sand plate 6332 is made of fine sand components, with better compactness and is more conducive to sound insulation. The first sand plate 6331 is made of coarse sand components, with more connected pores inside, which can allow sound waves to enter its interior, generate friction, and thus dissipate sound energy, playing a role in sound absorption, as shown in Figure 3 shown.

[0070] In this embodiment, the method of embedding and combining the first-layer sand plate 6331 with the grid plate 631 can make the substrate 633 and the grid plate 631 better combined together, with better integrity. At the same time, since the coefficient of thermal expansion of the grid plate 631 is greater than that of the substrate 633, by adopting the design method of embedding the first-layer sand plate 6331 into the grid plate 631, under the influence of high temperature, the grid plate 631 undergoes a greater high-temperature expansion, which can play a role in stretching and tearing the substrate 633, and is more conducive to the fracture and detachment of the substrate. The second-layer sand plate 6332 is higher than the grid plate 631 and serves as the outer surface, which can ensure the flatness of the outer surface of the noise reduction plate. In addition, pits are provided on the second-layer sand plate 6332, and a part of the first-layer sand plate 6331 is embedded in the pits.

[0071] In this embodiment, the plastic film 634 is attached to the frame 632, which can play a role in attaching and supporting the inner surface coating 636 before it is cured and formed.

[0072] In this embodiment, the spraying process is adopted to spray polyurea on the plastic film 634 to form the inner surface coating 636, and spray it on the second-layer sand plate 6332 to form the outer surface coating 635. The inner surface coating 636 and the outer surface coating 635 form a sealed, water-impermeable and air-impermeable cavity 637 for the frame 632, the grid plate 631 and the substrate 633.

[0073] In this embodiment, the inner surface coating 636 is adhered to the plastic film 634, playing a role in film sound absorption and protection, preventing the substrate 633 from being affected by water, scratches and collisions received through the inner surface. Among them, the combustion performance of the inner surface coating 636 and the outer surface coating 635 is Class B1.

[0074] In this embodiment, on the one hand, the outer surface coating 635 plays a role in protecting the substrate 633, having excellent waterproof, scratch-proof, abrasion-proof, light-aging-proof, etc. At the same time, the dense structure of this coating also has a sound insulation effect, and spraying it on the surface of the substrate 633 can further enhance the sound insulation. In this embodiment, the weighted sound insulation amount of the detachable noise reduction plate in this embodiment can reach 35 dB.

[0075] In this embodiment, when sound waves are incident on the inner surface coating 636, the inner surface coating 636 vibrates under the excitation of the sound wave pressure. The plastic film 634 and the inner surface coating 636 undergo bending deformation, and frictional losses occur inside them, consuming sound energy. At the same time, the inner surface coating 636 and the air layer sealed at the rear end form a resonance system, which can dissipate the sound near the resonance frequency well. In addition, since the substrate 633 part of the embedded grid plate 631 also has sound absorption characteristics, it is equivalent to filling the enclosed cavity with sound-absorbing materials, further promoting the improvement of the sound absorption coefficient. Under the above multiple effects, in the frequency range of 200 - 1600 Hz in the mid-low frequency, the sound absorption coefficient of this embodiment is 0.39 - 0.61. The sound absorption performance is the highest at 400 Hz, reaching 0.61. In the frequency range of 250 Hz - 1000 Hz (low-frequency range), the average sound absorption coefficient is about 0.55, which is particularly suitable for noise reduction of electrical equipment mainly with low-frequency noise such as converter transformers, improving the overall noise reduction performance.

[0076] Embodiment 2

[0077] Please refer to Figures 1 to 9 As shown, this embodiment also provides a preparation method for a fuseable noise reduction plate for extra-high voltage large oil-filled equipment, including the preparation method of the substrate 633:

[0078] Step 1: Take quartz sand grains of 60 - 100 mesh, stir them evenly with an adhesive, and pour them into the rectangular mold 10, as shown in Figure 4 As shown. After compacting and leveling it in the rectangular mold 10, use a roller mold 20 with protrusions, as shown in Figure 5 As shown, for rolling, so that a concave pit is formed on the smoothed surface, as shown in Figure 6 As shown. After compacting and forming, it is sent to an oven for the first baking process, baked at a temperature of 80 - 100 °C for 18 - 25 minutes to form the second sand plate 6332.

[0079] In this embodiment, quartz sand grains of 60 - 70 mesh and 80 - 100 mesh are weighed and mixed respectively, and the mass ratios are 60% and 40% respectively.

[0080] Step 2: Take aeolian sand of 20 - 40 mesh and stir it evenly with an adhesive;

[0081] Step 3: Align and place the grid plate 631 on the rectangular mold 10, evenly pour the stirred aeolian sand into the grid plate 631, and use a rolling mold 30 to roll the aeolian sand in each grid until it becomes a flat plate to form the first sand plate 6331, as shown in Figures 7 to 9 As shown.

[0082] In this embodiment, the grid plate 631 is placed on the rectangular mold 10. There are bosses on the outer edge of the rectangular mold 10, which can ensure that the grid plate 631 is exactly placed on the surface of the second-layer sand plate 6332, neither crushing the second-layer sand plate 6332 that has not been shaped in the first step nor forming a gap between the grid plate 631 and the second-layer sand plate 6332. Undoubtedly, the length of the roller on the rolling mold 30 matches the length of the square of the grid plate 631. When in use, the distance between two adjacent rollers on the rolling mold 30 is engaged on the grid plate shared by two squares. The well-mixed aeolian sand is evenly poured into each square, and the problem of more accumulation at one end of the square and less or no accumulation at the other end is minimized as much as possible.

[0083] Step Four: Send it into the oven for the second baking process, bake it for 50 - 70 minutes in an environment with a temperature of 120 - 170 °C to cure and form. After cooling, demold the rectangular mold at room temperature.

[0084] In this embodiment, the baking temperature in the first step is low and the baking time is short, which can enable the second-layer sand plate 6332 to have a certain strength after insufficient chemical reactions, and at the same time, it also reserves sufficient reaction conditions for the good fusion with the first-layer sand plate 6331 after the first-layer sand plate 6331 is added. At the same time, concave pits are pressed on the surface of the second-layer sand plate 6332, which can have a good bonding force with the first-layer sand plate 6331 to form an integral plate.

[0085] Please refer to Figures 1 to 9 As shown, this embodiment also provides a spraying method for the surface coating of a fusible noise reduction plate, including:

[0086] Step One: Place the assembled grid plate 631, frame 632, and substrate 633 with the second groove facing upwards, and wrap the outer surface of the entire frame 632 with the plastic film 634 to form a closed cavity 637 with the substrate 633, grid plate 631, and frame 632.

[0087] Step Two: Use a spraying device to spray polyurea on the plastic film 634 to form an inner surface polyurea coating 636.

[0088] Step Three: Turn it over so that the second groove faces downwards, and spray polyurea on the substrate 633 covering the grid plate 631 to form an outer surface polyurea coating 635.

[0089] In this embodiment, after adopting the above spraying process, a closed air layer can be formed inside the detachable noise reduction plate. Thus, when the inner surface coating 636 encounters sound, it can form a resonance system with the air layer in the cavity 637 to play a sound absorption role.

[0090] In this embodiment, since the mass ratio of the gravel reaches about 95%, the combustion performance of the substrate 633 can reach B1 level or above, which ensures that when a fire occurs in the equipment, the detachable noise reduction board will not increase the fire, thus improving safety. At the same time, a high particle mass ratio can also cause the detachable noise reduction board to melt into small fragments when it melts at high temperature, avoiding the problem that large pieces may block the fire area after falling off and then continue to block fire extinguishing.

[0091] Comparative example

[0092] Impedance tube test:

[0093] The structure of Comparative Example 1 is a microparticle board impedance tube sound absorption test sample without a film;

[0094] Please refer to Figure 10 As shown, the structure of Comparative Example 1 is a fusible noise reduction board with a diameter of 100 mm bonded to a steel pipe with a diameter of 100 mm and a length of 100 mm, forming an open space with a thickness of 100 mm at the front end and a microparticle noise reduction board with a thickness of 20 mm. This sample is used for normal incidence sound absorption, mainly for comparison.

[0095] The structure of Comparative Example 2 is a sample with a polyurea coating sprayed on the surface of the fusible noise reduction board;

[0096] Please refer to Figure 11 As shown, the structure of Comparative Example 2 is a polyurea coating sprayed on the surface of a fusible noise reduction board with a diameter of 100 mm and a thickness of 20 mm. During the test, it is installed in the impedance tube. According to the common dimensions in engineering applications, a cavity with a length of 100 mm is left at the front end, so as to measure its normal incidence sound absorption performance, mainly for comparison.

[0097] The structure of this embodiment, a thin-film structure impedance tube sound absorption test sample;

[0098] Please refer to Figure 12 As shown, the structure of this embodiment is a 100 mm thick cavity, a 20 mm thick microparticle board combined with a polyurea film, and on the basis of the impedance tube measurement structure of Comparative Example 1, the open end of the steel pipe is sealed with a polyurea film, so that the normal incidence sound absorption coefficient of the structure of this embodiment can be measured by using the impedance tube.

[0099] In this embodiment, it should be noted that the above-mentioned structure samples of Comparative Examples 1 and 2 and this embodiment are all impedance tube tests. The required test sample size is small, mainly for exploratory tests during the product R & D stage, which can improve the test efficiency and reduce the R & D cost.

[0100] In this embodiment, it should be noted that generally, when the sound absorption coefficient is lower than 0.2, it is considered that it has no sound absorption performance. Only when it is higher than 0.2 is it considered to have sound absorption performance. In addition, three samples are made for the structures of Comparative Examples 1 and 2 and this embodiment to avoid data contingency.

[0101] Please refer to Figure 13 the impedance tube absorption curve of the structure of Comparative Example 1 (bare board, no film structure) shown in the figure. According to the curve, the absorption performance of the structure of Comparative Example 1 is poor, specifically manifested as basically no absorption performance below 200 Hz, and the absorption performance between 200 Hz and 1600 Hz does not exceed 0.3. This is because sound waves can enter the inside of the fusible particle board, causing the sound energy to be dissipated in the gaps between the particles inside the particle board, thus having a certain absorption performance. However, due to the need to consider other functions such as fusing for the fusible particle board, the particles are very dense, resulting in a not very high porosity inside the particle board, and thus the absorption performance is poor.

[0102] Please refer to Figure 14 the impedance tube absorption curve of the structure of Comparative Example 2 (bare board surface sprayed with polyurea but no film structure) shown in the figure. According to the curve, the normal incidence absorption coefficient of the structure of Comparative Example 2 in each frequency band is less than 0.2, and there is basically no absorption performance. This is because after the surface of the particle board is sprayed with a polyurea coating, sound waves can no longer enter the gaps between the particles, so that the sound energy cannot be dissipated, and thus there is basically no absorption performance.

[0103] Please refer to Figure 15 the impedance tube absorption curve of the structure of this embodiment shown in the figure. According to the curve, the normal absorption performance of the structure of this embodiment has been significantly improved. In the low-frequency range of 125 Hz to 500 Hz, the average absorption coefficient is about 0.54, and it has good absorption performance. Especially at 250 Hz and 315 Hz, it reaches the peak value, and the peak value is 0.73 - 0.9.

[0104] Please refer to Figure 16 the impedance tube absorption curves of three structures shown in the figure. The three structures are specifically the structure of this embodiment, the structure of Comparative Example 1, and the structure of Comparative Example 2. According to the comparison curves, by adopting the structure of this embodiment, the absorption performance of the fusible noise reduction board has been significantly improved. Especially in the range of 125 Hz - 500 Hz (low-frequency range), the average absorption coefficient is about 0.54, and the absorption performance is good, which is especially suitable for noise reduction of electrical equipment mainly with low-frequency noise such as converter transformers.

[0105] Reverberation chamber absorption test:

[0106] Please refer to Figure 17 the reverberation absorption test sample of the structure of this embodiment shown in the figure. The reverberation chamber absorption test structure of this embodiment is made according to the structure during impedance tube testing, and a sample with a corresponding area is made according to the size requirements of reverberation chamber absorption for reverberation chamber absorption test. The test results are relatively close to the actual engineering application scenario, and this test is mainly used for detection during product finalization.

[0107] Please refer to Figure 18As shown, it is the reverberation absorption curve of the structure of this embodiment. According to the curve, the reverberation absorption performance of the structure of this embodiment is good. In the frequency range of 200 - 1600 Hz in the mid - low frequency, the absorption coefficient is 0.39 - 0.61. The absorption performance is the highest at 400 Hz, reaching 0.61. In the range of 250 Hz - 1000 Hz (low - frequency range), the average absorption coefficient is about 0.55. It is particularly suitable for noise reduction of electrical equipment mainly with low - frequency noise such as converter transformers, improving the overall noise reduction performance.

[0108] Comparison example of improved load - bearing performance:

[0109] 1. The area of the sample test piece in this embodiment is 0.615×3 = 1.845 m 2 , before adding weight, the height from the ground is 600 mm; when adding weight to 450 kg for the first time, the height from the ground is 597 mm; when adding weight to 900 kg for the second time, the height from the ground is 594 mm; when adding weight to 1200 kg for the third time, the height from the ground is 591 mm; when adding weight to 1500 kg for the fourth time, the height from the ground is 589.5 mm. After maintaining the weight of 1500 kg for 7 hours, the height from the ground did not continue to decrease. During the whole process, there are no cracks on the panel, and the support skeleton has no obvious deformation or cracking. Its load - bearing performance is greater than 1500 / 1.845 = 813 kg / m 2 ;

[0110] 2. The area of the control sample (the previous fusible noise - reducing board) is 0.615×3 = 1.845 m 2 , before adding weight, the height from the ground is 600 mm; when adding weight to 150 kg for the first time, the height from the ground is 598.4 mm. After maintaining the weight of 150 kg for 7 hours, the height from the ground decreased slightly. During the whole process, there are no cracks on the panel, and the support skeleton has no obvious deformation or cracking; when adding weight to 450 kg for the second time, the height from the ground is 593.2 mm. During the process of maintaining the weight of 450 kg for 7 hours, cracks, deformation and fracture occurred on the panel. Its load - bearing performance is less than 450 / 1.845 = 243.9 kg / m 2 ;

[0111] In summary, the load - bearing performance of the sample in this embodiment is greater than 813 kg / m 2 , significantly better than that of the previous fusible noise - reducing board with a load - bearing performance less than 243.9 kg / m 2 , its load - bearing performance has been significantly improved, without the need to mark the load - bearing area and non - load - bearing area, nor the need to add anti - fall nets, significantly improving the on - site construction efficiency and reducing the safety risks of personnel maintenance operations.

[0112] Embodiment 3

[0113] Please refer to Figure 19As shown, this embodiment also provides a soundproof enclosure, the top cover of which is applied with the fusible noise reduction plate for ultra-high voltage large oil-filled equipment described in Example 1. Figure 19 Reference numeral 630 indicates a fusible noise reduction board.

[0114] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0115] The above-described embodiments merely represent implementation methods of the invention. The protection scope of the present invention is not limited to the above-described embodiments. For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A fuseable noise reduction plate for extra-high voltage large oil-filled equipment, characterized in that, Including: A grid plate (631), a frame (632), a substrate (633), and a plastic film (634); The grid plate (631) is connected to the frame (632). The substrate (633) includes a porous first-layer sand plate (6331) and a second-layer sand plate (6332). The first-layer sand plate (6331) is embedded in the grid plate (631), and the second-layer sand plate (6332) covers the grid plate (631); The plastic film (634) wraps the frame (632) to form a closed cavity (637) with the grid plate (631) embedded in the substrate (633). And a surface coating is sprayed on the plastic film (634) and the second-layer sand plate (6332); The plastic film (634) faces the sound source and forms a resonance system with the air layer in the cavity (637) when encountering sound.

2. The fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 1, wherein The surface coating is airtight and waterproof, including an outer surface coating (635) and an inner surface coating (636). The inner surface coating (636) is located on the plastic film (634), and the outer surface coating (635) is located on the second-layer sand plate (6332).

3. The fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 1, characterized in that, The material of the airtight and waterproof surface coating is polyurea.

4. The fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 1, wherein The first-layer sand plate (6331) uses a coarse sand component, and the second-layer sand plate (6332) uses a fine sand component.

5. The fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 1, characterized in that, Pits are provided on the second-layer sand plate (6332), and a part of the first-layer sand plate (6331) is embedded in the pits.

6. The fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 1, wherein The frame (632) is a groove-structured frame, including a first groove, and the grid plate (631) is fixedly located in the first groove.

7. The fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 1, characterized in that, The frame (632) includes a second groove. The second groove and the first-layer sand plate (6331) serve as the skeleton of the cavity (637), and together with the plastic film (634), form a closed cavity (637).

8. The fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 2, wherein During use, when sound waves are incident on the inner surface coating (636), the inner surface coating (636) vibrates under the excitation of the sound wave pressure. The plastic film (634) and the inner surface coating (636) undergo bending deformation, and frictional losses occur inside them, consuming sound energy. At the same time, the resonance system dissipates the resonant sound waves. After the sound waves outside the remaining resonance frequency enter its cavity (637), they generate friction with the pores in the substrate (633) to dissipate sound energy.

9. A preparation method of a fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to any one of claims 1-8, characterized in that, Among them, The preparation method of the substrate (633) includes: Taking quartz sand grains of 60 - 100 meshes, stirring them evenly with an adhesive, and pouring them into a rectangular mold (10). After compacting and leveling them in the rectangular mold (10), using a roller mold (20) with protrusions for rolling to form a pit on the flattened surface. After compacting and forming, it is sent to an oven for the first baking process to form the second-layer sand plate (6332); Taking aeolian sand of 20 - 40 meshes and stirring it evenly with an adhesive; Aligning the grid plate (631) and placing it on the rectangular mold (10), evenly pouring the stirred aeolian sand into the grid plate (631), and using a rolling mold (30) to roll the aeolian sand in each grid until it becomes a flat plate to form the first-layer sand plate (6331). Then it is sent to an oven for the second baking process for curing and forming; After cooling, demold the rectangular mold at room temperature.

10. The preparation method of the fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 9, characterized in that, The baking temperature and baking time in the second baking process are higher than those in the first baking process.

11. The preparation method of the fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 10, characterized in that, The baking temperature in the first baking process is 80 - 100 °C, and the baking time is 18 - 25 minutes; the baking temperature in the second baking process is 120 - 170 °C, and the baking time is 50 - 70 minutes.

12. The preparation method of the fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 9, characterized in that, Among them, A spraying method for the surface coating of the fusible noise reduction board includes: For the assembled grid plate (631), frame (632), and substrate (633), make the second groove in the frame (632) face upward, and wrap the outer surface of the entire frame (632) with a plastic film (634); Use a spraying device to spray polyurea on the plastic film (634) to form an inner surface coating (636); Turn it over so that the second groove faces downward, and spray polyurea on the second layer of sand plate (6332) to form an outer surface coating (635).

13. The preparation method of the fusing noise reduction plate for extra-high voltage large oil-filled equipment according to claim 9, characterized in that, When designing the distance between two adjacent protrusions on the drum mold (20), the grid size on the grid plate (631) is considered.

14. The preparation method of the fusing noise reduction plate for extra-high voltage large oil-filled equipment according to claim 13, wherein, When the drum mold (20) is in use, the formed pits are within the grids of the grid plate (631).

15. The preparation method of the fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 9, characterized in that, The length of the drum on the rolling mold (30) matches the length of the grid on the grid plate (631).

16. The preparation method of the fuseable noise reduction plate for extra-high voltage large oil-filled equipment according to claim 9, characterized in that, When in use, the distance between two adjacent drums on the rolling mold (30) is engaged on the grid plate shared by two grids.

17. A sound insulation enclosure, characterized in that, The sound insulation cover includes a top cover, and the top cover uses the fusible noise reduction board for extra-high voltage large oil-filled equipment described in any one of claims 1 - 8.

Images