Fusing noise reduction plate for extra-high voltage large oil charging equipment, preparation method and acoustic shield

Abstract

The invention discloses a fusible noise reduction plate for extra-high voltage large oil charging equipment, a preparation method and a sound insulation cover. The fusible noise reduction plate comprises a grid plate, a frame, a base plate and a plastic film. The grid plate is connected with the frame, part of the substrate is embedded into the grid plate, and part of the substrate protrudes out of the grid plate; the frame is wrapped by the plastic film, so that the frame and the grid plate embedded into the substrate form a closed cavity; a surface coating is sprayed on the plastic film and the substrate of the convex grid plate; the plastic film faces a sound source and forms a resonance system with the air layer in the cavity when meeting sound. The fusible noise reduction plate has sound insulation and sound absorption functions while having a high-temperature falling function, the noise reduction capacity of the sound insulation cover is improved, and meanwhile the excellent bearing performance is achieved.

Description

Technical Field

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

[0002] In order to meet the noise reduction and fire emergency needs of large-scale UHV oil-filled equipment (converter transformers), a soundproof cover is usually set up on the periphery, and a high-temperature shedding structure is set up on the top cover of the soundproof cover to ensure that the top cover of the soundproof cover has an automatic opening function in the event of a fire, providing favorable conditions for external firefighting to effectively act on the fire source. The current converter transformer mainly adopts the high-temperature shedding solution as a fusible noise reduction board solution.

[0003] The fusible noise reduction board solution uses a self-fusible noise reduction board as the main body of noise reduction. The fusible noise reduction board is made of sand and polymer adhesive. When a fire occurs in the equipment, the noise reduction board will melt into small pieces under the action of high temperature and fall down, allowing the top cover of the sound insulation cover to be opened, thus providing a way for external fire fighting.

[0004] However, in the fusible noise reduction board solution, due to the material, the fusible noise reduction board 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 construction site, which can easily damage the noise reduction board. For example, the strength of the fusible noise reduction board drops sharply after being exposed to rain, and it may deform or even fall off. For example, in actual use, there have been incidents of water seepage, falling or cracking of fusible noise reduction boards in converter stations during operation, which makes it difficult to meet actual operation needs.

[0005] In order to improve the surface protection ability of the fusible noise reduction board, a polyurea coating is sprayed on the surface of the fusible noise reduction board to solve the problems of bumps, scratches and waterproofing. For example, in the prior art, the invention patent with publication number CN115007427A discloses a method for treating a substrate by spraying polyurea and the substrate produced therefrom. The substrate produced in this patent 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, the waterproof performance of the substrate surface is improved by spraying polyurea on the substrate. When used in 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 board lose its sound absorption function, and can only achieve sound insulation and noise reduction based on its own material, but cannot absorb sound, and has poor noise reduction ability.

[0006] In addition, after the noise reduction board on the top cover of the soundproof enclosure is installed, in order to ensure safety, the load-bearing area and non-load-bearing area must be marked on the top cover, and a fall prevention net must be added to prevent maintenance personnel in the station from standing on the non-load-bearing area while carrying out maintenance work, causing safety accidents such as falling. The load-bearing performance of the fusible noise reduction board cannot yet meet the needs of engineering applications. Summary of the invention

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

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: A fusible noise reduction plate for ultra-high voltage large oil-filled equipment, comprising: 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, and the substrate 633 is partially embedded in the grid plate 631 and partially protrudes from 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 substrate 633 protruding from the grid plate 631; The plastic film 634 faces the sound source and forms a resonance system with the air layer in the cavity 637 when encountering sound.

[0009] In one embodiment of the present invention, the surface coating is airtight and watertight, 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 of the protruding grid plate 631 .

[0010] In one embodiment of the present invention, the material of the air-impermeable and water-impermeable surface coating is polyurea.

[0011] In one embodiment of the present invention, the substrate 633 includes a first layer of sanding plate 6331 and a second layer of sanding plate 6332 ; the first layer of sanding plate 6331 is embedded in the grid plate 631 , and the second layer of sanding plate 6332 protrudes from the grid plate 631 .

[0012] In one 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.

[0013] In one embodiment of the present invention, a pit is provided on the second sanding plate 6332, and a portion of the first sanding plate 6331 is embedded in the pit.

[0014] In one 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.

[0015] In one 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 are combined with the plastic film 634 to form a closed cavity 637 .

[0016] In one 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 are bent and deformed, and friction loss occurs inside each of them, consuming sound energy; at the same time, the resonance system dissipates the resonant sound waves, and the remaining sound waves outside the resonance frequency enter its cavity 637 and generate friction with the pores in the substrate 633 to dissipate the sound energy.

[0017] The present invention also provides a method for preparing a fusible noise reduction plate for ultra-high voltage large oil-filled equipment, wherein the method for preparing the substrate 633 comprises: Take 60-100 mesh quartz gravel and mix it with the adhesive evenly, then pour it into the rectangular mold 10; compact and smooth it in the rectangular mold 10, and use a roller mold 20 with convexities to roll it to form a pit on the smooth surface; after compaction and shaping, send it into the oven for the first baking process to form the second layer of sand plate 6332; Take 20-40 mesh aeolian sand and mix it evenly with the adhesive; Align the grid plate 631 and place it on the rectangular mold 10, pour the stirred aeolian sand evenly into the grid plate 631, and use the rolling mold 30 to roll the aeolian sand in each grid until it becomes a flat plate, forming the first layer of sand plate 6331; send it into the oven for the second baking process to solidify and shape; After cooling, the rectangular mold is demoulded at room temperature.

[0018] In one embodiment of the present invention, the baking temperature and baking time of the second baking process are greater than the baking temperature and baking time of the first baking process.

[0019] In one 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.

[0020] In one embodiment of the present invention, a method for spraying a surface coating of a fusible noise reduction plate comprises: Assemble the grid plate 631, the frame 632, and the base plate 633 so that the second groove in the frame 632 faces upwards, and wrap the outer surface of the entire frame 632 with a plastic film 634; The polyurea is sprayed onto the plastic film 634 using a spraying device to form an inner surface coating 636; The surface is turned over so that the second groove faces downward, and polyurea is sprayed on the base plate 633 of the protruding grid plate 631 to form an outer surface coating 635.

[0021] In one embodiment of the present invention, the distance between two adjacent protrusions on the roller mold 20 is designed by taking into account the size of the grid on the grid plate 631.

[0022] In one embodiment of the present invention, when the roller mold 20 is in use, the formed pits are located within the grids of the grid plate 631 .

[0023] In one embodiment of the present invention, the length of the roller on the rolling die 30 matches the square length of the grid plate 631 .

[0024] In one embodiment of the present invention, the distance between two adjacent rollers on the rolling mold 30 is engaged with a grid plate shared by two grids when in use.

[0025] The present invention also provides a soundproof enclosure, the top cover of which is applied with the above-mentioned fusible noise reduction plate for ultra-high voltage large oil-filled equipment.

[0026] Compared with the prior art, the present invention has the following beneficial effects: First, the present invention combines film resonance sound absorption and porous sound absorption, so that the detachable noise reduction board has sound absorption performance. In the past, the fusible noise reduction board only had sound insulation performance. Although there was sound absorption by the sound absorber inside the soundproof enclosure, the sound absorption area inside the soundproof enclosure was not large, so the reverberation sound inside the soundproof enclosure was relatively large. On the one hand, it worsened the sound environment of the personnel working inside the soundproof enclosure. On the other hand, the increase in the reverberation sound inside the soundproof enclosure also offset the sound insulation capacity of the soundproof enclosure, and the overall noise reduction performance of the soundproof enclosure was poor. The present invention makes full use of the elastic properties of the polyurea coating and the porous sound absorption properties of the particulate material, so that the fusible noise reduction board has excellent sound absorption performance, reduces the reverberation sound inside the soundproof enclosure, and improves the noise reduction capacity of the soundproof enclosure.

[0027] Second, compared with previous fusible noise reduction panels, the detachable noise reduction panel of the present invention has better load-bearing performance, avoiding the risk of personnel falling when performing maintenance work on it. More maintenance equipment, instruments, etc. can be placed on it. At the same time, there is no need to mark the load-bearing area and non-load-bearing area, nor is there a need to add an anti-fall net, which significantly improves on-site construction efficiency and reduces the risk of maintenance for personnel. In the past, the fusible noise reduction board adopted the structural form of 20mm thick fusible particle board combined with supporting frame. The supporting frame adopts 1.5mm thick galvanized steel plate folded into 15mm×30mm×15mm channel steel shape, and the two ends are connected to the outer frame. In order to prevent the over-dense frame from affecting the high-temperature shedding of the fusible particle board, the frame spacing is 300mm~600mm, and the grid width formed by the frame and the outer frame is 300mm~600mm. The grid length is 600mm~750mm. The load-bearing limit value generally does not exceed 500kg / m². With the influence of sunlight aging, rain and other effects of the fusible particle board, its load-bearing performance is greatly reduced, and it is concave and deformed downward. Not only is there a risk of falling when someone works on it, but there is even a risk of the fusible particle board itself falling, which poses a great hidden danger. Although some solutions have adopted the method of spraying polyurea coating on the surface to improve the damage resistance and aging performance of the fusible noise reduction board, the load-bearing capacity has not been improved due to structural reasons, especially within the interval of the frame, where the load-bearing capacity is the worst, followed by the top of the frame. In order to prevent people from falling when standing on it or damaging the fusible noise reduction board due to excessive weight, area markings are made on the fusible noise reduction board on the top cover of the sound insulation cover, dividing the load-bearing area and non-load-bearing area, and adding anti-fall nets, which increases the construction process and significantly affects the commissioning efficiency of the new station.

[0028] Third, the present invention also proposes to use a separated rolling mold with a limited pressure depth to compact the micro-particle mortar and use a plastic film as a support for spraying polyurea, which not only ensures the feasibility of the production process, but also simplifies the production process and improves production efficiency. The substrate adopts a two-layer structure design. The first layer of sand plate is located on the outer layer as a sound insulation layer, and is mixed with quartz sand. The second layer of sand plate is located on the inner layer as a sound absorption layer, and is aeolian sand, so that it has both sound insulation and sound absorption functions. The substrate is compacted and baked in two steps during preparation. The first layer of sand plate needs to be baked at a low temperature and for a short time to perform an incomplete chemical reaction. At the same time, it also reserves sufficient reaction conditions for the second layer of sand plate to be well integrated after being added, and then the second layer of sand plate is formed and baked as a whole. In addition, pits need to be pressed out of the inner surface of the first layer of sand plate before baking so that the two layers of sand plates can have a good bonding degree.

[0029] The sprayed polyurea on the outer surface plays a role in strengthening sound insulation. The sprayed polyurea forms an airtight and closed cavity inside the entire fusible noise reduction board. The polyurea on the inner surface is a thin film, which plays a role in thin film sound absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of a fusible noise reduction plate for ultra-high voltage large-scale oil-filled equipment according to an embodiment of the present invention.

[0031] Figure 2 Schematic diagram of a grid plate according to an embodiment of the present invention.

[0032] Figure 3 Schematic diagram of a grid plate and a substrate according to an embodiment of the present invention.

[0033] Figure 4 Schematic diagram of a rectangular mold according to an embodiment of the present invention.

[0034] Figure 5 Schematic diagram of a roller mold according to an embodiment of the present invention.

[0035] Figure 6 Schematic diagram of a pit according to an embodiment of the present invention.

[0036] Figure 7 It is a schematic diagram of the alignment of a rectangular mold and a grid plate according to an embodiment of the present invention.

[0037] Figure 8 Schematic diagram of a rolling die according to an embodiment of the present invention.

[0038] Fig. 9 Schematic diagram of a rolling mold, a substrate and a grid plate according to an embodiment of the present invention.

[0039] Fig.10 This is a real shot of the structure of comparative example 1 of the impedance tube test of an embodiment of the present invention.

[0040] Fig.11 This is a real shot of the structure of comparative example 2 of the impedance tube test of an embodiment of the present invention.

[0041] Fig.12 This is a real shot of the impedance tube of an embodiment of the present invention testing the structure of the present invention.

[0042] Fig.13 This is a sound absorption curve diagram of the impedance tube of the comparative example 1 of the embodiment of the present invention.

[0043] Fig.14 This is a sound absorption curve diagram of the impedance tube of the comparative example 2 of the embodiment of the present invention.

[0044] Fig.15 It is a sound absorption curve diagram of the impedance tube of the structure of the present invention according to an embodiment of the present invention.

[0045] Fig.16 The impedance tube sound absorption curves of the inventive structure of the embodiment of the present invention, the structure of comparative example 1, and the structure of comparative example 2 are shown.

[0046] Fig.17 This is a real picture of the reverberation sound absorption test sample of the structure of the present invention according to the embodiment of the present invention.

[0047] Fig.18 It is a reverberation sound absorption curve diagram of the structure of the present invention according to an embodiment of the present invention.

[0048] Fig.19 Schematic diagram of a soundproof enclosure according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described in conjunction with the accompanying drawings of the specification.

[0050] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0051] See also Figures 1 to 3 As shown, this embodiment provides a fusible noise reduction plate for ultra-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, and the substrate 633 is partially embedded in the grid plate 631 and partially protrudes from 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. An airtight and watertight surface coating is sprayed on the plastic film 634 and the substrate 633 protruding from the grid plate 631, so that a closed air layer is formed inside the fusible noise reduction plate. The plastic film 634 faces the sound source, and when encountering sound, it forms a resonance system with the air layer, which plays a role of film resonance sound absorption.

[0052] 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 of the protruding grid plate 631. More specifically, the material of the airtight and watertight surface coating is polyurea.

[0053] See also Figure 2As shown, in this embodiment, the grid plate 631 is made of flat steel and twisted steel bars, wherein the flat steel is 2-4 mm thick, 25 mm-50 mm wide, and the twisted steel bars are 2 mm-5 mm in diameter. The flat steel and the twisted steel bars are welded in a grid shape, and the specifications of the grid are 120-160 mm in length and 120-160 mm in width. After the grid plate 631 is welded and formed, the surface is hot-dip galvanized to improve the anti-corrosion performance.

[0054] In this embodiment, the grid plate 631 has a square size of 150 mm × 150 mm, which makes it easier for the base plate 633 to fuse and ensures the support safety of the workers standing on it. At the same time, the support structure of the steel grid effectively improves the load-bearing performance of the noise reduction plate, which can meet the uniform load of 4 kN / ㎡ and the concentrated load of 4 kN within the range of 0.1 m wide × 0.25 m long.

[0055] In this embodiment, the frame 632 is a groove structure frame, including a first groove and a second groove. When manufacturing, it is first made of galvanized steel plate, first bent into two grooves, and then welded into shape. Among them, the grid plate 631 is fixed in the first groove. When welding, the parts between the frames 632 and the parts where the frames 632 and the grid plates 631 are connected are fully welded to ensure airtightness.

[0056] In this embodiment, the substrate 633 is formed by polymerizing about 95% sand particles and about 5% polymer adhesive, and has a total thickness of 18-22 mm. In this embodiment, the substrate 633 includes a first layer of sand plate 6331 and a second layer of sand plate 6332.

[0057] The first layer of sand plate 6331 is embedded in the grid plate 631, and the second layer of sand plate 6332 is the outer surface of the detachable noise reduction plate, which can ensure the surface is flat. The second layer of sand plate 6332 is made of fine sand, which has better density and is more conducive to sound insulation. The first layer of sand plate 6331 is made of coarse sand, which has more interconnected pores inside, allowing sound waves to enter its interior, generating friction, thereby dissipating sound energy and playing a role in sound absorption. Figure 3 shown.

[0058] In this embodiment, the method of embedding the first layer of sand plate 6331 and the grid plate 631 can better combine the substrate 633 and the grid plate 631 together, and the integrity is better. At the same time, since the thermal expansion coefficient of the grid plate 631 is greater than the thermal expansion coefficient of the substrate 633, the design method of embedding the first layer of sand plate 6331 into the grid plate 631 is adopted. Under the influence of high temperature, the grid plate 631 undergoes greater high-temperature expansion, which can play a role in stretching and tearing the substrate 633, which is more conducive to the breakage and fall of the substrate. The second layer of sand plate 6332 is higher than the grid plate 631, and as the outer surface, it can ensure the flatness of the outer surface of the noise reduction plate. In addition, a pit is set on the second layer of sand plate 6332, and the first layer of sand plate 6331 is partially embedded in the pit.

[0059] In this embodiment, the plastic film 634 is attached to the frame 632 to attach and support the inner surface coating 636 before it is cured.

[0060] In this embodiment, the polyurea is sprayed on the plastic film 634 to form an inner surface coating 636, and is sprayed on the second sand plate 6332 to form an outer surface coating 635. The inner surface coating 636 and the outer surface coating 635 form a closed, watertight, and airtight cavity 637 with the frame 632, the grid plate 631, and the base plate 633.

[0061] In this embodiment, the inner surface coating 636 and the plastic film 634 are bonded together to play the role of film sound absorption and protection, preventing the substrate 633 from being affected by water, scratches and collisions through the inner surface. The combustion performance of the inner surface coating 636 and the outer surface coating 635 is B1 level.

[0062] In this embodiment, the outer surface coating 635 protects the substrate 633 and has excellent waterproof, scratch-resistant, rubbing-resistant, light-resistant, etc. At the same time, the dense structure of the 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 of the detachable noise reduction board of this embodiment can reach 35dB.

[0063] In this embodiment, when a sound wave is 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 are bent and deformed, and friction loss occurs inside each of them, consuming sound energy. At the same time, the inner surface coating 636 and the air layer sealed at the rear end also form a resonance system, which can well dissipate the sound near the resonance frequency. In addition, since the substrate 633 part embedded in the grid plate 631 also has sound absorption characteristics, it is equivalent to filling the closed cavity with sound absorption material, which further promotes the improvement of the sound absorption coefficient. Under the above-mentioned multiple effects, the sound absorption coefficient of this embodiment is 0.39-0.61 in the medium and low frequency range of 200-1600Hz, and the sound absorption performance is the highest at 400Hz, reaching 0.61. In the range of 250Hz-1000Hz (low frequency range), the average sound absorption coefficient is about 0.55, which is particularly suitable for noise reduction of electrical equipment with low-frequency noise as the main component, such as converter transformers, and improves the overall noise reduction performance.

[0064] Example 2 See also Figures 1 to 9 As shown, this embodiment also provides a method for preparing a fusible noise reduction plate for ultra-high voltage large oil-filled equipment, including a method for preparing a substrate 633: Step 1: Take 60-100 mesh quartz gravel and mix it with the adhesive and pour it into the rectangular mold 10. Figure 4 As shown, after compacting and smoothing it in a rectangular mold 10, a roller mold 20 with convexities is used. Figure 5 As shown, rolling is performed to form a pit on the flat surface. Figure 6 After compaction and forming, it is sent to the oven for the first baking process, and baked at a temperature of 80-100°C for 18-25 minutes to form the second layer of sand plate 6332.

[0065] In this embodiment, quartz gravel with mesh sizes of 60-70 and 80-100 are weighed and mixed, with the mass proportions being 60% and 40% respectively.

[0066] Step 2: Take 20-40 mesh aeolian sand and mix it evenly with the adhesive; Step 3: Align the grid plate 631 and place it on the rectangular mold 10, pour the stirred aeolian sand evenly into the grid plate 631, and use the rolling mold 30 to roll the aeolian sand in each grid until it becomes a flat plate, forming the first layer of sand plate 6331. Figure 7~Figure 9 shown.

[0067] In this embodiment, the grid plate 631 is placed on the rectangular mold 10. The outer edge of the rectangular mold 10 has a boss to ensure that the grid plate 631 is placed on the surface of the second layer of sand plate 6332, and the second layer of sand plate 6332 that has not been finalized in the first step is not crushed, and a gap is not formed between the second layer of sand plate 6332. There is no doubt that the length of the roller on the rolling mold 30 matches the grid length of the grid plate 631, and the spacing between two adjacent rollers on the rolling mold 30 is engaged on the grid plate shared by the two grids when in use. The stirred aeolian sand is evenly poured into each grid, and the problem of more accumulation at one end of the grid and less or no accumulation at the other end is minimized as much as possible.

[0068] Step 4: Send it to the oven for the second baking process, bake it at 120~170℃ for 50~70 minutes to solidify it. After cooling, demould the rectangular mold at room temperature.

[0069] In this embodiment, the first step of baking has a low temperature and a short baking time, which can make the second layer of sand plate 6332 have a certain strength after an insufficient chemical reaction, and also keep sufficient reaction conditions for good fusion after adding the first layer of sand plate 6331. At the same time, the second layer of sand plate 6332 has pits pressed on the surface, which can have a good bonding force with the first layer of sand plate 6331 to form an integral plate.

[0070] See also Figures 1 to 9 As shown, this embodiment also provides a method for spraying a surface coating of a fusible noise reduction plate, comprising: Step 1: Assemble the grid plate 631 , frame 632 , and substrate 633 with the second groove facing upward, and wrap the entire outer surface of the frame 632 with the plastic film 634 to form a closed cavity 637 with the substrate 633 , grid plate 631 , and frame 632 .

[0071] Step 2: Use a spraying device to spray polyurea onto the plastic film 634 to form a polyurea coating 636 on the inner surface.

[0072] Step 3: Turn the substrate 633 of the protruding grid plate 631 over so that the second groove faces downward, and spray polyurea on the substrate 633 to form a polyurea coating 635 on the outer surface.

[0073] In this embodiment, after adopting the above-mentioned spraying process, a closed air layer can be formed inside the removable noise reduction plate, so that 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 role in sound absorption.

[0074] In this embodiment, since the mass proportion of gravel reaches about 95%, the combustion performance of the base plate 633 can reach B1 level or above, which ensures that when the equipment is on fire, the removable noise reduction plate will not increase the fire, thereby improving safety. At the same time, the high mass proportion of particles can also make the removable noise reduction plate melt into small pieces when it melts at high temperature, avoiding the problem that large pieces may cover the fire part after falling off and continue to block the fire extinguishing.

[0075] Comparative Example Impedance tube test: The structure of Comparative Example 1 is a particle board impedance tube sound absorption test sample without a film; See also Fig.10 As shown, the structure of comparative example 1 is that a fusible noise reduction plate with a diameter of 100 mm is bonded to a steel pipe with a diameter of 100 mm and a length of 100 mm to form an open space with a thickness of 100 mm at the front end and a particle noise reduction plate with a thickness of 20 mm. This sample is used for vertical incident sound absorption, mainly for comparison.

[0076] The structure of Comparative Example 2 is a sample after the surface of the fusible noise reduction plate is sprayed with a polyurea coating; See also Fig.11 As shown, the structure of comparative example 2 is to spray polyurea coating on the surface of a fusible noise reduction plate with a diameter of 100 mm and a thickness of 20 mm. During the test, it was installed in an impedance tube, and a 100 mm long cavity was left at the front end according to the common size in engineering applications, so as to measure its vertical incident sound absorption performance, which is mainly used for comparison.

[0077] The structure of this embodiment is a thin film structure impedance tube sound absorption test sample; See also Fig.12 As shown, the structure of this embodiment is a 100 mm thick cavity, a 20 mm thick particle board combined with a polyurea film, and on the basis of the impedance tube measurement structure in comparative example 1, the open end of the steel pipe is sealed with a polyurea film, so that the vertical incidence sound absorption coefficient of the structure of this embodiment can be measured using an impedance tube.

[0078] In this embodiment, it should be noted that the structural sample tests in the above-mentioned comparative examples 1, 2 and this embodiment are all impedance tube tests, and the required test sample size is relatively small, which is mainly used for exploratory tests in the product development stage, which can improve test efficiency and reduce R&D costs.

[0079] In this embodiment, it should be noted that, generally speaking, when the sound absorption coefficient is lower than 0.2, it is considered to have no sound absorption performance. When it is higher than 0.2, it is considered to have sound absorption performance. In addition, three samples were made for the structures of comparative examples 1 and 2 and this embodiment to avoid the randomness of the data.

[0080] See also Fig.13As shown, the impedance tube sound absorption curve of the structure of comparative example 1 (bare board, no film structure). According to the curve, the sound absorption performance of the structure of comparative example 1 is poor, specifically, there is basically no sound absorption performance below 200Hz, and the sound absorption performance of 200Hz-1600Hz does not exceed 0.3. This is because the sound wave can enter the inside of the fusible particle board, so that the sound energy is dissipated in the gaps between the particles inside the particle board, so that it has a certain sound absorption performance. However, since the fusible particle board needs to consider other functions such as fusing, the particles are very dense, so that the porosity in the particle board is not too high, so the sound absorption performance is poor.

[0081] See also Fig.14 As shown in the figure, the impedance tube sound absorption curve of the structure of comparative example 2 (bare board surface sprayed with polyurea but without film structure). According to the curve, the vertical incidence sound absorption coefficient of the structure of comparative example 2 in each frequency band is less than 0.2, and there is basically no sound absorption performance. This is because after the polyurea coating is sprayed on the surface of the particle board, the sound waves can no longer enter the gaps between the particles, so that the sound energy cannot be dissipated, and therefore there is basically no sound absorption performance.

[0082] See also Fig.15 As shown in the figure, the impedance tube sound absorption curve of the structure of this embodiment shows that the vertical sound absorption performance of the structure of this embodiment is significantly improved. The average sound absorption coefficient in the low frequency range of 125Hz to 500Hz is about 0.54, which has good sound absorption performance, especially at 250Hz and 315Hz, reaching a peak value of 0.73-0.9.

[0083] See also Fig.16 As shown, there are three structures of impedance tube sound absorption curves, specifically, the structure of this embodiment, the structure of comparative example 1 and the structure of comparative example 2. According to the comparison curve, by adopting the structure of this embodiment, the sound absorption performance of the fusible noise reduction plate is significantly improved. In particular, the average sound absorption coefficient in the 125Hz-500Hz range (low-frequency range) is about 0.54, and the sound absorption performance is good, which is particularly suitable for noise reduction of electrical equipment with low-frequency noise as the main component, such as converter transformers.

[0084] Reverberation chamber sound absorption test: See also Fig.17 The figure shows the reverberation sound absorption test sample of the structure of this embodiment. The reverberation chamber sound absorption test structure of this embodiment is made according to the structure of the impedance tube test, and samples of corresponding areas are made according to the size requirements of the reverberation chamber sound absorption to carry out the reverberation chamber sound absorption test. The test results are relatively close to the actual practical scenarios of the project, and this test is mainly used for testing when the product is finalized.

[0085] See also Fig.18As shown in the figure, it is a reverberation sound absorption curve of the structure of the present embodiment. According to the curve, the reverberation sound absorption performance of the structure of the present embodiment is good. In the medium and low frequency range of 200-1600Hz, the sound absorption coefficient is 0.39-0.61, and the sound absorption performance is the highest at 400Hz, reaching 0.61. In the range of 250Hz-1000Hz (low frequency range), the average sound absorption coefficient is about 0.55, which is particularly suitable for noise reduction of electrical equipment with low-frequency noise as the main component, such as converter transformers, and improves the overall noise reduction performance.

[0086] Comparative example of load-bearing performance improvement: 1. The sample specimen area of ​​this embodiment is 0.615×3=1.845m 2 Before adding weight, the height from the ground was 600mm; the first time the weight was added to 450kg, the height from the ground was 597mm; the second time the weight was added to 900kg, the height from the ground was 594mm; the third time the weight was added to 1200kg, the height from the ground was 591mm; the fourth time the weight was added to 1500kg, the height from the ground was 589.5mm. After maintaining the weight at 1500kg for 7 hours, the height from the ground did not continue to decrease. During the whole process, there were no cracks on the panel, and there was no obvious deformation or cracking of the supporting frame. Its load-bearing capacity was greater than 1500 / 1.845=813kg / m 2 ; 2. Control sample (conventional fusible noise reduction board) area 0.615×3=1.845 m 2 Before adding weight, the height from the ground was 600mm; the first time the weight was added to 150kg, the height from the ground was 598.4mm, and after keeping the weight at 150kg for 7 hours, the height from the ground slightly decreased. During the whole process, the panel had no cracks, and the supporting frame had no obvious deformation or cracking; the second time the weight was added to 450kg, the height from the ground was 593.2mm, and the weight was kept at 450kg for 7 hours, the panel cracked, deformed and broke, and its load-bearing performance was less than 450 / 1.845=243.9kg / m 2 ; In summary, the load-bearing capacity of the sample in this embodiment is greater than 813 kg / m 2 , significantly better than the previous fusible noise reduction board, the load-bearing performance is less than 243.9kg / m 2 Its load-bearing performance is significantly improved. There is no need to mark the load-bearing area and non-load-bearing area, nor is there a need to add a fall prevention net, which significantly improves on-site construction efficiency and reduces the safety risks of personnel maintenance operations.

[0087] Example 3 See also Fig.19 As 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. Fig.19 Reference numeral 630 indicates a fusible noise reduction board.

[0088] 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.

[0089] 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 fusible noise reduction plate for ultra-high voltage large oil-filled equipment, characterized in that: include: Grid plate (631), frame (632), substrate (633), plastic film (634); The grid plate (631) is connected to the frame (632), and the substrate (633) is partially embedded in the grid plate (631) and partially protrudes from 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); and a surface coating is sprayed on the plastic film (634) and the substrate (633) protruding from the grid plate (631); 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 fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 1 is characterized in that: The surface coating is airtight and watertight, and comprises 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) of the protruding grid plate (631).

3. The fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 1 is characterized in that: The air-tight and water-tight surface coating is made of polyurea.

4. The fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 1, characterized in that: The base plate (633) comprises a first layer of sanding plate (6331) and a second layer of sanding plate (6332); the first layer of sanding plate (6331) is embedded in the grid plate (631), and the second layer of sanding plate (6332) protrudes from the grid plate (631).

5. The fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 4, characterized in that: The first sanding plate (6331) has a coarse sand component, and the second sanding plate (6332) has a fine sand component.

6. The fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 4, characterized in that: The second layer of sanding plate (6332) is provided with a concave pit, and the first layer of sanding plate (6331) is partially embedded in the concave pit.

7. The fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 1, characterized in that: The frame (632) is a groove structure frame, comprising a first groove, and the grid plate (631) is fixedly located in the first groove.

8. The fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 4, characterized in that: 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 are combined with the plastic film (634) to form a closed cavity (637).

9. The fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 2, characterized in that: During use, when sound waves are incident on the inner surface coating (636), the inner surface coating (636) vibrates under the stimulation of the sound wave pressure, the plastic film (634) and the inner surface coating (636) are bent and deformed, and friction loss occurs inside each of them, consuming sound energy; at the same time, the resonance system dissipates the resonant sound waves, and the remaining sound waves outside the resonance frequency enter its cavity (637) and generate friction with the pores in the substrate (633) to dissipate the sound energy.

10. A method for preparing a fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to any one of claims 1 to 9, characterized in that: in, The method for preparing the substrate (633) comprises: Take 60-100 mesh quartz gravel and mix it with a binder and pour it into a rectangular mold (10); compact and smooth it in the rectangular mold (10), and use a roller mold (20) with a protrusion to roll it to form a pit on the smooth surface; after compaction and shaping, send it into an oven for the first baking process to form a second layer of sand plate (6332); Take 20-40 mesh aeolian sand and mix it evenly with the adhesive; Align the grid plate (631) and place it on the rectangular mold (10), pour the stirred aeolian sand evenly into the grid plate (631), and use the rolling mold (30) to roll the aeolian sand in each grid until it becomes a flat plate, thereby forming a first layer of sand plate (6331); and send it into a baking oven for a second baking process to solidify and shape it; After cooling, the rectangular mold is demoulded at room temperature.

11. The method for preparing the fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 10, characterized in that: The baking temperature and baking time of the second baking process are greater than the baking temperature and baking time of the first baking process.

12. The method for preparing the fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 11, characterized in that: The baking temperature of the first baking process is 80~100℃, and the baking time is 18~25 minutes; the baking temperature of the second baking process is 120~170℃, and the baking time is 50~70 minutes.

13. The method for preparing the fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 10, characterized in that: in, The spraying method of the surface coating of the fusible noise reduction board comprises: Assemble the grid plate (631), the frame (632), and the base plate (633) so that the second groove in the frame (632) faces upwards, and wrap the entire outer surface of the frame (632) with a plastic film (634); Using a spraying device to spray polyurea onto the plastic film (634) to form an inner surface coating (636); The surface is turned over so that the second groove faces downward, and polyurea is sprayed on the base plate (633) of the protruding grid plate (631) to form an outer surface coating (635).

14. The method for preparing the fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 10, characterized in that: The spacing between two adjacent protrusions on the roller mold (20) is designed by taking into account the size of the grid on the grid plate (631).

15. The method for preparing the fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 14, characterized in that: When the roller mold (20) is in use, the formed pits are located within the grids of the grid plate (631).

16. The method for preparing the fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 10, characterized in that: The length of the roller on the rolling die (30) matches the square length of the grid plate (631).

17. The method for preparing the fusible noise reduction plate for ultra-high voltage large oil-filled equipment according to claim 10, characterized in that: The distance between two adjacent rollers on the rolling die (30) is such that, when in use, they are engaged with a grid plate shared by two grids.

18. A soundproof enclosure, characterized in that: The top cover of the soundproof enclosure is applied with the fusible noise reduction plate for ultra-high voltage large oil-filled equipment as described in any one of claims 1-9.

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