Soundproof test chamber

Abstract

The application discloses a sound insulation test box, and relates to the technical field of acoustic testing, comprising a box body and a top cover plate, wherein the box body comprises an outer layer box body, an inner layer box body and a sound absorption layer formed by sound absorption material filled between the outer layer box body and the inner layer box body, and the top cover plate is arranged at the upper end opening of the box body. The outer layer box body and the inner layer box body are integrally casted by hardenable paste material, and the wall thickness of the outer layer box body is greater than that of the inner layer box body; the wall body of the outer layer box body and the wall body of the inner layer box body are respectively provided with damping structures formed by the templates reserved during casting; and the top cover plate is provided with a sample frame for mounting a sample to be tested. The sound insulation test box eliminates the joint gap through integral casting, the matching frequency of the inner and outer layers is staggered by using the asymmetric thickness design, and the matching effect is inhibited by the damping structures formed by the templates, so that the box body has good sound insulation performance; meanwhile, the sample frame realizes rapid positioning and mounting of the sample to be tested.

Description

Technical Field

[0001] This application relates to the field of acoustic testing technology, and more specifically, to a sound insulation testing box. Background Technology

[0002] In the sound insulation performance testing of building materials, small sound insulation test chambers are widely used due to their low cost and small footprint. Existing small sound insulation test chambers mostly employ methods such as... Figure 1 The metal sheets shown are welded together to form a single-layer box structure, or as shown in the example... Figure 2 The diagram shows a structure with a double-layered metal plate and sound-absorbing material filling the middle. However, regardless of whether it's a single-layer or double-layered structure, the enclosure formed by welding the metal plates has seams, allowing sound waves to easily leak from these seams, making it difficult for the enclosure's own sound insulation to meet the test requirements. Furthermore, the double-layered metal plate structure also has the problem of its inherent resonant frequency easily falling within the test frequency band. When the frequency of external sound waves approaches this resonant frequency, the enclosure resonates, causing an abnormally low level of sound insulation in that frequency band. In addition, for pre-cured engineered wood samples, the sample needs to be fixed to the opening at the top of the enclosure during testing. Existing devices typically use adhesive or compression methods to install the sample, which is cumbersome and lacks a standardized positioning structure.

[0003] Therefore, how to improve the sound insulation of the small sound insulation test box itself and its sound insulation performance stability across the entire frequency band, and improve the convenience and positioning accuracy of prefabricated sample installation, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a sound insulation test box to solve the technical problems of insufficient sound insulation of existing small sound insulation boxes, resonance interference testing of the box body, and inconvenience of prefabricated sample installation.

[0005] A sound insulation test box includes a box body and a top cover plate. The box body includes an outer box body, an inner box body, and a sound-absorbing layer. The inner box body is disposed inside the outer box body. The sound-absorbing material is filled between the outer box body and the inner box body to form the sound-absorbing layer. The top cover plate is disposed at the upper opening of the box body.

[0006] Both the outer and inner boxes are integrally cast from a hardenable slurry material, and the wall thickness of the outer box is greater than that of the inner box.

[0007] Damping structures are respectively provided on the walls of the outer box and the inner box. The damping structures are formed by the template retained during casting. The template is tightly bonded to the hardenable slurry material.

[0008] The top cover plate is provided with a sample frame, which is used to install the sample to be tested.

[0009] In some embodiments, both the outer casing and the inner casing are shell structures, and the upper dimensions of the outer casing and the inner casing are larger than the lower dimensions.

[0010] In some embodiments, both the outer box and the inner box are inverted truncated pyramid shapes.

[0011] In some embodiments, the angle between the sidewall of the outer casing and the vertical direction is different from the angle between the sidewall of the inner casing and the vertical direction.

[0012] In some embodiments, the wall thickness of the outer casing is more than twice the wall thickness of the inner casing.

[0013] In some embodiments, the damping structure includes a first constraint damping layer attached to the outer side of the wall of the outer housing, a second constraint damping layer attached to the inner side of the wall of the outer housing, a third constraint damping layer attached to the outer side of the wall of the inner housing, and a fourth constraint damping layer attached to the inner side of the wall of the inner housing.

[0014] In some embodiments, the template is a resin template.

[0015] In some embodiments, the sound-absorbing layer is a porous sound-absorbing material layer.

[0016] In some embodiments, the top cover includes an inner cover, an outer cover, and an intermediate layer. The inner cover is disposed at the upper opening of the inner layer housing, the outer cover is disposed above the inner cover, and the intermediate layer is disposed between the inner cover and the outer cover. The outer cover is provided with the sample frame. The inner cover is provided with a first clearance hole at a position corresponding to the sample frame, and the intermediate layer is provided with a second clearance hole at a position corresponding to the sample frame. The inner wall of the second clearance hole is provided with a sealing strip.

[0017] In some embodiments, the outer cover includes a rigid layer and a flexible layer, which are alternately stacked along the thickness direction of the outer cover.

[0018] In some embodiments, the rigid layer is a mortar layer and the flexible layer is a rubber layer.

[0019] In some embodiments, the intermediate layer is in contact with the sound-absorbing layer.

[0020] In some embodiments, a support member is provided between the outer box and the inner box, the support member being supported between the bottom outer side of the inner box and the bottom inner side of the outer box.

[0021] In some embodiments, the support member is an elastic support member.

[0022] In some embodiments, the gap between the inner wall of the sample frame and the sample to be tested is filled with a flexible sealing material.

[0023] And / or, a flexible shock-absorbing material layer is provided on the bottom support surface of the sample frame.

[0024] In some embodiments, a sound level meter and a suspension assembly are also included, the suspension assembly comprising multiple flexible elastic ropes, the sound level meter being suspended by the flexible elastic ropes in the central region of the inner housing.

[0025] The sound insulation test chamber provided in this application includes a chamber body and a top cover. The chamber body includes an outer chamber body, an inner chamber body, and a sound-absorbing layer. The inner chamber body is located inside the outer chamber body. Sound-absorbing material is filled between the outer and inner chamber bodies to form a sound-absorbing layer. The top cover is located at the upper opening of the chamber body. Both the outer and inner chamber bodies are integrally cast from a hardenable slurry material, and the wall thickness of the outer chamber body is greater than that of the inner chamber body. Damping structures are respectively provided on the walls of the outer and inner chamber bodies. The damping structures are formed by the template retained during casting, and the template is tightly bonded to the hardenable slurry material. The top cover is provided with a sample frame for mounting the sample to be tested. This application embodiment eliminates seams by using a double-layer box structure formed by integral casting. The asymmetrical thickness design of the outer box with a wall thickness greater than that of the inner box makes the matching frequencies of the inner and outer layers staggered. The damping structure formed by retaining the template suppresses the matching effect. The three work together to give the box itself good sound insulation performance. At the same time, a sample frame is set on the top cover plate to realize the rapid positioning and installation of prefabricated test samples. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a sound insulation test box with a single-layer box structure in the prior art;

[0028] Figure 2 This is a schematic diagram of a sound insulation test box with a double-layer enclosure structure in the prior art;

[0029] Figure 3 This is a schematic cross-sectional view of the overall structure of the sound insulation test box disclosed in the embodiments of this application;

[0030] Figure 4 for Figure 3The diagram shows a cross-sectional view of the sound insulation test chamber when the sample to be tested is installed.

[0031] The annotations in the attached figures are explained as follows:

[0032] 100 is the enclosure, 110 is the outer enclosure, 111 is the support component, 120 is the inner enclosure, and 130 is the sound-absorbing layer.

[0033] 200 is the top cover plate, 210 is the inner cover, 211 is the first clearance hole, 220 is the outer cover, 221 is the mortar layer, 222 is the rubber layer, 223 is the sample frame, 230 is the middle layer, 231 is the second clearance hole, 232 is the sealing strip, and 240 is the sealing plate.

[0034] 300 is a sound level meter, and 310 is a flexible elastic rope;

[0035] 400 represents the sample to be tested. Detailed Implementation

[0036] This application discloses a sound insulation test box to solve the technical problems of insufficient sound insulation of existing small sound insulation boxes, resonance interference testing of the box body, and inconvenience in installing prefabricated samples.

[0037] In the description of this application, it should be noted that "multiple" refers to two or more. Ordinal numbers such as "first," "second," etc., are used only to distinguish different elements or components and should not be construed as indicating or implying relative importance, order, or quantity, nor should they be construed as requiring simultaneous existence—for example, in some embodiments, only one constraint damping layer may be provided without the other. "Installation," "connection," and "fitting" should be interpreted broadly. For example, they can refer to fixed connections (such as welding, bonding, or bolting), detachable connections (such as threaded connections or snap-fit ​​connections), or integral connections (such as integral casting); they can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Unless otherwise explicitly specified and limited, the terms "substantially the same," "substantially parallel," "substantially perpendicular," etc., regarding positional or angular relationships, all include the range allowed by processing, assembly, and measurement errors known in the art; for example, angular deviations can be within ±5° without affecting the fit. Expressions such as "about" and "approximately" mentioned in this application should be understood as being able to vary within ±10% of the value. The terms "exemplary," "optionally," and "in some implementations" used in this application are intended to list various possible implementations to illustrate that the technical solution of this application is not limited to a specific implementation.

[0038] Combination Figure 1 and Figure 2Existing small sound insulation test chambers mostly use welded metal sheets to form the chamber, which has the following problems: the welded metal sheet chamber has seams, and sound waves can easily leak from the seams, making it difficult for the chamber's own sound insulation to meet the test requirements; the inherent resonant frequency of the double-layer metal sheet structure is likely to fall within the test frequency band, and when the external sound wave frequency approaches this resonant frequency, the chamber will resonate, causing an abnormally low sound insulation level in this frequency band; for pre-cured artificial board samples, the sample needs to be fixed at the opening at the top of the chamber during testing. Existing devices usually use adhesive or pressing methods to install the sample, which is cumbersome and lacks a standardized positioning structure.

[0039] Based on this, this application discloses a sound insulation test box, combined with Figure 3 and Figure 4 The device includes a housing 100 and a top cover 200. The housing 100 includes an outer housing 110, an inner housing 120, and a sound-absorbing layer 130. The inner housing 120 is located inside the outer housing 110. Sound-absorbing material is filled between the outer housing 110 and the inner housing 120 to form the sound-absorbing layer 130. The top cover 200 is located at the upper opening of the housing 100. Both the outer housing 110 and the inner housing 120 are integrally cast from a hardenable slurry material, and the wall thickness of the outer housing 110 is greater than that of the inner housing 120. Damping structures are respectively provided on the walls of the outer housing 110 and the inner housing 120. The damping structures are formed by the template retained during casting, and the template is tightly bonded to the hardenable slurry material. The top cover 200 is provided with a sample frame 223, which is used to install the sample 400 to be tested. This embodiment eliminates seams by using a double-layer box structure formed by integral casting. The asymmetrical thickness design, where the wall thickness of the outer box 110 is greater than that of the inner box 120, causes the matching frequencies of the inner and outer layers to be staggered. The damping structure formed by retaining the template suppresses the matching effect. The three work together to give the box itself good sound insulation performance. At the same time, a sample frame 223 is set on the top cover plate 200 to realize the rapid positioning and installation of the prefabricated test sample 400.

[0040] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0041] Please see Figure 3 and Figure 4 This application discloses a sound insulation test chamber, including a chamber body 100 and a top cover plate 200. The chamber body 100 is used to form a test cavity, and the top cover plate 200 is disposed at the upper opening of the chamber body 100, together with the chamber body 100 to form a closed test space.

[0042] The enclosure 100 includes an outer enclosure 110, an inner enclosure 120, and a sound-absorbing layer 130. The inner enclosure 120 is a monolithically cast enclosure structure, and its inner surface can be leveled by heavy-duty plastering to provide a flat testing space for the sample 400 to be tested. The inner enclosure 120 is located inside the outer enclosure 110, forming a sandwich space between the inner enclosure 120 and the outer enclosure 110. This sandwich space is filled with sound-absorbing material to form the sound-absorbing layer 130.

[0043] A support member 111 is also provided between the outer enclosure 110 and the inner enclosure 120. The support member 111 is supported between the bottom outer side of the inner enclosure 120 and the bottom inner side of the outer enclosure 110. It is used to support the inner enclosure 120 and maintain the relative position and spacing between the outer enclosure 110 and the inner enclosure 120, ensuring that the thickness of the interlayer space is uniform and stable, thereby providing a uniform filling space for the sound-absorbing layer 130. In some embodiments, the support member 111 is an elastic support member, which can be exemplarily a rubber block, rubber pad, or spring. The elastic support member can not only ensure the positioning accuracy between the outer enclosure 110 and the inner enclosure 120, but also form an elastic buffer between them, preventing the vibration of the outer enclosure 110 from being directly transmitted to the inner enclosure 120 through the rigid connection, thereby cutting off the solid-borne sound transmission path and further improving the sound insulation performance of the enclosure.

[0044] Both the outer casing 110 and the inner casing 120 are integrally cast from a hardenable grout material. The hardenable grout material is a micro-expansion material with a density ≥2.0 g / cm³. For example, the hardenable grout material can be cement-based self-leveling concrete, cement-based self-compacting concrete, or other high-density hardenable grout materials. The outer casing 110 and the inner casing 120 are formed by integral casting, with no seams, thus preventing sound wave leakage from the seams.

[0045] The outer enclosure 110 has a wall thickness of 50mm to 90mm. For example, the wall thickness of the outer enclosure 110 can be 50mm, 60mm, 70mm, 80mm, or 90mm. The inner enclosure 120 has a wall thickness of 30mm to 45mm. For example, the wall thickness of the inner enclosure 120 can be 30mm, 35mm, 40mm, or 45mm. The wall thickness of the outer enclosure 110 is greater than the wall thickness of the inner enclosure 120. Preferably, the wall thickness of the outer enclosure 110 is twice or more than the wall thickness of the inner enclosure 120. According to the acoustic critical frequency law, by designing the outer wall thickness to be twice or more than the inner wall thickness, the coincidence frequencies of the outer enclosure 110 and the inner enclosure 120 are separated by a multiple, thereby achieving decoupling of the coincidence valley and ensuring that the sound insulation curve of the enclosure 100 is smooth and without obvious dips across the entire frequency range. Simultaneously, by coordinating the areal density m1 of the outer enclosure 110 and the areal density m2 of the inner enclosure 120, setting m2 to 0.3 to 0.5 times m1, the inherent resonant frequency f0 of the entire system can be shifted below 50Hz. This ensures that the enclosure 100 itself does not generate resonance enhancement within the standard test frequency band of 100Hz to 3150Hz, guaranteeing a low and stable background noise. The sound-absorbing layer 130 formed by filling with sound-absorbing material can also increase the equivalent density of the system and help reduce the resonant frequency.

[0046] Please see Figure 4 Both the outer casing 110 and the inner casing 120 are shell structures, and the upper dimensions of both are larger than the lower dimensions.

[0047] In some embodiments, both the outer casing 110 and the inner casing 120 are inverted frustum shapes. The angle between the sidewall of the outer casing 110 and the vertical direction is 0 to 10 degrees. When the angle is 0 degrees, the outer casing 110 is cuboid (this is still a shell structure where the upper dimension is larger than the lower dimension, which can be considered a special case of an inverted frustum). The angle between the sidewall of the inner casing 120 and the vertical direction is 10 to 15 degrees. The angle between the sidewall of the outer casing 110 and the sidewall of the inner casing 120 differs by at least 10 degrees. The distance between the inner wall of the outer casing 110 and the outer wall of the inner casing 120 gradually increases from the upper end of the casing 100 to the lower end of the casing 100. Because the inclination angle of the inner enclosure 120's sidewalls is greater than that of the outer enclosure 110's sidewalls, the sound-absorbing layer 130 filling the middle forms a wedge-shaped space with a gradually varying thickness, i.e., a structure that is thinner at the top and thicker at the bottom. The inclined, non-parallel walls break the axial standing wave mode that is easily generated in a rectangular cavity, making the internal sound pressure distribution more uniform; the gradually varying thickness of the sound-absorbing layer 130 forms a spatial gradient impedance, achieving efficient absorption of wide-band sound energy, especially low-frequency residual sound energy, making the sound field inside the enclosure 100 tend to be in a uniform diffusion state.

[0048] In other embodiments, the outer box 110 and the inner box 120 can also be in the shape of a regular square truncated pyramid, that is, the upper dimension is smaller than the lower dimension. Its direction of sound wave reflection is opposite to that of the inverted square truncated pyramid, but the acoustic principle is the same, and it can also play the role of breaking standing waves. However, since the regular square truncated pyramid shape is narrower at the top and wider at the bottom, the assembly of the inner box 120 and the sound-absorbing layer 130 is more difficult, and the processing of the template without disassembly is more difficult. Therefore, the inverted square truncated pyramid is the preferred solution.

[0049] It is understood that the outer box 110 and the inner box 120 are not limited to the inverted truncated pyramid shape described above. In other embodiments, a frustum shape, a multi-faceted shape, or other truncated cone shell structures with an upper dimension larger than a lower dimension can also be used, as long as non-parallel opposing walls can be formed. These alternative shapes can also break the axial standing waves between parallel walls, and the structure with a larger upper part and a smaller lower part facilitates the demolding operation after casting.

[0050] Damping structures are respectively provided on the walls of the outer box 110 and the inner box 120. Specifically, the damping structure includes a first constraint damping layer attached to the outer side of the outer box 110 wall, a second constraint damping layer attached to the inner side of the outer box 110 wall, a third constraint damping layer attached to the outer side of the inner box 120 wall, and a fourth constraint damping layer attached to the inner side of the inner box 120 wall. That is to say, the outer box 110 uses double-layer molds (inner and outer sides) during casting, and after casting, the molds on both sides are retained, with the grout sandwiched between the two layers of molds, forming a three-layer composite structure of "constraint damping layer - grout layer - constraint damping layer". The inner box 120 is also cast using double-layer molds, forming the same three-layer composite structure. When the constraint damping layers of both the outer casing 110 and the inner casing 120 are not removed, the casing and the sound-absorbing layer 130 together form a seven-layer composite structure of "constraint damping layer - cast-in-place layer - constraint damping layer - sound-absorbing layer - constraint damping layer - cast-in-place layer - constraint damping layer", which can reflect and absorb sound waves from multiple interface layers. The above-mentioned double-layer constraint damping structure can constrain the slurry layer from both the inside and outside. When bending waves are transmitted, shear deformation occurs between the slurry layer and the constraint damping layers on both sides, converting mechanical energy into heat energy, effectively suppressing the coincidence effect and smoothing out the coincidence trough of a single slurry material.

[0051] For example, the template can be a resin template, specifically an industrial resin turnover box with a natural draft angle can be used as a template that does not need to be removed. When casting the outer box 110 and the inner box 120, the resin turnover box is used as a template. After casting, the template is not removed. The permanently retained resin shell is tightly bonded to the internal high-density slurry to form the aforementioned constraint damping layer.

[0052] In some implementations, one or two of the constraint damping layers can be removed as needed, but the constraint effect will be reduced accordingly.

[0053] The sound-absorbing layer 130 is a porous sound-absorbing material layer. Exemplarily, the sound-absorbing layer 130 can be a rock wool layer, glass wool layer, mineral wool layer, or polyester fiber layer. The thickness of the sound-absorbing layer 130 is 50mm to 100mm; exemplaryly, the thickness of the sound-absorbing layer 130 can be 50mm, 60mm, 70mm, 80mm, 90mm, or 100mm. The porous sound-absorbing material has tiny gaps and continuous pores. When sound waves propagate within it, they cause air vibrations, generating friction and viscous dissipation between the sound waves and the pore walls, converting some of the sound energy into heat energy, thereby absorbing transmitted sound energy and further improving sound insulation performance. Simultaneously, the sound-absorbing layer 130 forms an impedance mismatch interface with the adjacent slurry layer, increasing sound wave reflection at the interface and reducing the transmitted sound energy.

[0054] Please see Figure 3 The top cover 200 includes an inner cover 210, a middle layer 230, and an outer cover 220. The inner cover 210 is located at the upper opening of the inner housing 120, the outer cover 220 is located above the inner cover 210, and the middle layer 230 is located between the inner cover 210 and the outer cover 220. The outer cover 220 has a sample frame 223, in which the sample to be tested 400 is installed. The depth of the sample frame 223 matches the thickness of the sample to be tested 400, and a gap of 0.5cm to 1.0cm is reserved between the inner sidewall of the sample frame 223 and the sample to be tested 400 to facilitate the placement of the sample to be tested 400. For example, for a sample to be tested 400 with a planar dimension of 300mm × 300mm, the opening size of the sample frame 223 can be set to 310mm × 310mm. The gap between the inner wall of the sample frame 223 and the sample 400 to be tested is filled with a sealing material. This sealing material can be an elastic sealing material to form an airtight seal and prevent air from leaking from the edge of the sample 400 to be tested.

[0055] Furthermore, a flexible damping material layer can be provided at the bottom support surface of the sample frame 223. This flexible damping material layer supports the sample 400 to be tested and forms an elastic barrier between the sample 400 and the sample frame 223, preventing the sample 400 from rigidly contacting the sample frame 223 and forming an acoustic bridge. For example, the flexible damping material layer can be a rubber layer with a thickness of 5 mm or more and a Shore hardness of less than 20.

[0056] The inner cover 210 has a first clearance hole 211 at the position corresponding to the sample frame 223, and the middle layer 230 has a second clearance hole 231 at the position corresponding to the sample frame 223. The inner wall of the second clearance hole 231 is provided with a sealing strip 232, which can be formed of mortar or other rigid materials, such as gypsum board, and is used to seal the exposed part of the middle layer 230.

[0057] Specifically, the inner cover 210 can be made of 3cm thick mortar and has internal steel bars to ensure that the inner cover 210 has sufficient structural strength and surface density, and to avoid deformation or cracking when subjected to pressure or temperature changes, thereby ensuring the sealing reliability between the inner cover 210 and the inner box 120.

[0058] A flexible sealing material can be provided between the inner cover 210 and the inner housing 120, and a flexible sealing material can be provided between the outer cover 220 and the upper edge of the outer housing 110. For example, the flexible sealing material can be a rubber gasket, a sealing strip, or a silicone gasket. The flexible sealing material ensures airtightness and also provides some vibration isolation, preventing vibration of the housing 100 from being transmitted to the sample 400 through the top cover 200.

[0059] The intermediate layer 230 can be a rock wool layer, which is in contact with the sound-absorbing layer 130 filled between the outer box 110 and the inner box 120. Specifically, the intermediate layer 230 is located above the inner cover 210, and the sound-absorbing layer 130 fills the outside of the inner box 120. When the top cover 200 is closed on the upper opening of the box 100, the lower surface of the intermediate layer 230 and the upper end of the sound-absorbing layer 130 are in direct contact and interconnected at the contact surface, forming a continuous sound absorption channel. In this way, the rock wool material of the intermediate layer 230 and the sound-absorbing layer 130 are spatially integrated, and sound waves do not need to pass through an additional interface when propagating between the intermediate layer 230 and the sound-absorbing layer 130, reducing the reflection loss of sound energy at the interface and improving the sound absorption efficiency.

[0060] The outer cover 220 may include a rigid layer and a flexible layer, which are alternately stacked along the thickness direction of the outer cover 220. Specifically, the rigid layer may be a mortar layer 221, and the flexible layer may be a rubber layer 222. In some embodiments, the outer cover 220 consists of a first mortar layer, a first rubber layer, a second mortar layer, a second rubber layer, and a third mortar layer from bottom to top, forming a five-layer rubber-insulated composite structure of "mortar-rubber-mortar-rubber-mortar". The mortar layer, as a high areal density mass layer, provides sound insulation, while the rubber layer, as a damping layer, provides elastic decoupling and shear damping dissipation between adjacent mortar layers. The alternating stacking of these two layers causes sound waves to undergo multiple reflections and transmission losses at each interface as they pass through the layers. Simultaneously, the shear damping effect of the rubber layer converts bending wave energy into heat energy, effectively suppressing the coincidence effect of the top cover plate 200.

[0061] The thickness of each mortar layer 221 can be the same or different. Preferably, the thickness of the first mortar layer is 2 cm, the thickness of the second mortar layer is 4 cm, and the thickness of the third mortar layer is 1 cm, with unequal thicknesses. This unequal thickness ensures that the resonant frequencies of each mortar layer are staggered, preventing multiple layers from resonating and overlapping at the same frequency, further improving the sound insulation stability of the top cover plate 200 across the entire frequency range. In some embodiments, reinforcing bars are distributed within each mortar layer 221. In some embodiments, the thickness of each rubber layer 222 is 0.5 cm to 1 cm. The density of the third mortar layer is ≥2.0 g / cm³.

[0062] In some embodiments, the outer cover 220 of the top cover plate 200 may not use the aforementioned five-layer rubber-insulated structure, but instead employs alternating layers of rigid and flexible layers, such as a three-layer structure sandwiching two layers of rubber, as long as the basic structural feature of alternating rigid and flexible layers is maintained. The size of the sample frame 223 is not limited to 300mm × 300mm, but can also be 200mm × 200mm or 400mm × 400mm. The number of sample frames 223 can also be multiple, allowing multiple test samples 400 to be installed simultaneously for comparative testing.

[0063] Furthermore, combined Figure 3 A sealing plate 240 is provided between the outer cover 220 and the intermediate layer 230. The sealing plate 240 can be formed of gypsum board or plaster mortar and is used to seal the exposed rock wool portion of the intermediate layer 230. The sealing plate 240 has a third clearance hole at the position corresponding to the sample frame 223, which corresponds to the position of the second clearance hole 231 of the intermediate layer 230, so as to avoid blocking the sound transmission of the sample 400 under test during the test.

[0064] Please continue reading. Figure 3 The sound insulation test chamber disclosed in this application also includes a sound level meter 300 and a suspension assembly. The suspension assembly includes multiple flexible elastic ropes 310. The sound level meter 300 is suspended in the central region of the inner chamber 120 by the flexible elastic ropes 310. The flexible elastic ropes 310 have high damping characteristics; exemplarily, the flexible elastic ropes 310 can be made of polymer rubber or latex thread. One end of the flexible elastic rope 310 is fixed to the top or upper end of the side wall of the inner chamber 120, and the other end is connected to the sound level meter 300. The multiple flexible elastic ropes 310 suspend the sound level meter 300 in the central region of the inner cavity from different directions, so that there is no rigid contact between the sound level meter 300 and the chamber 100. This design completely cuts off the "sound bridge" path of structural vibration of the chamber 100 transmitted to the outer shell of the sound level meter 300 through the side wall of the chamber, ensuring that the sound pressure signal collected by the sound level meter 300 is pure airborne sound, rather than a signal contaminated by structural vibration.

[0065] The following describes the method of using the sound insulation test box disclosed in the embodiments of this application, in conjunction with the above structural description.

[0066] When conducting airborne sound insulation testing, the sample 400 to be tested is first installed inside the sample frame 223 of the top cover plate 200. The sample 400 is a prefabricated sample, i.e., a pre-cured artificial board sample, which can be, for example, a mortar board, a rubber board, or a sound-insulating coating board. The sample 400 is placed inside the sample frame 223, leaving a gap of 0.5cm to 1.0cm between the sample 400 and the inner wall of the sample frame 223. Then, the gap is sealed with a sealing material to form an airtight seal between the sample frame 223 and the sample 400. After sealing, the top cover plate 200 is closed over the opening at the top of the enclosure 100. The inner cover 210 is sealed to the inner enclosure 120 with a flexible sealing material, and the outer cover 220 is sealed to the edge of the outer enclosure 110 with a flexible sealing material. The sound source is placed outside the enclosure 100 to form a reverberation field near the sample 400 within the test frequency band. The sound level meter 300 is suspended in the central area of ​​the inner enclosure 120 via a flexible elastic rope 310 to measure the sound pressure level inside the enclosure 100. Simultaneously, the sound pressure level outside the enclosure is measured, and the difference in sound pressure levels inside and outside the enclosure is calculated to obtain the airborne sound insulation of the sample 400 under test. During testing, it should be ensured that the sound insulation of the sample 400 differs from the airborne sound insulation of the enclosure 100 and the top cover 200 by at least 6 dB, to guarantee that the measured value reflects the sound insulation performance of the sample 400 itself rather than the transmitted sound from the enclosure 100.

[0067] During the impact sound insulation test, the sample 400 to be tested is also installed inside the sample frame 223. If the size of the sample 400 is greater than or equal to the size of the standard impactor, the sample surface is directly struck using the standard impactor. If the size of the sample 400 is smaller than the size of the standard impactor, a steel ball with a mass of 200g to 500g is used as the impact sound source. The steel ball is dropped freely from a height of more than 5cm and impacted 10 times at the same location. The contact area between the sample frame 223 and the sample 400 is isolated from lateral sound transmission using flexible damping material. When the sound insulation of the enclosure body reaches more than 20dB, the sample frame 223 does not need to be sealed. The sound level meter 300 collects the sound pressure level data inside the enclosure, recording the sound pressure level data every 20ms.

[0068] During the impact sound test, the sound level meter 300 continuously recorded the sound pressure level data within the enclosure 100 at a sampling frequency of once every 20 ms. The sound pressure signal generated by each impact event presented a complete pulse waveform in the time domain, consisting of a peak and adjacent troughs. The maximum sound pressure level at the peak of this pulse waveform was selected as the effective sound pressure level of that impact. To ensure the statistical reliability of the measurement results, at least 10 effective impacts were repeated at the same test location, and the maximum sound pressure level at each frequency was extracted for each impact using the method described above. For each frequency point, the sound pressure levels measured from multiple impacts were first averaged by energy, and then expressed in dB as the final impact sound pressure level for that frequency.

[0069] The sound insulation test chamber disclosed in this application has a sound insulation level of over 40dB, which is superior to existing small sound insulation chambers (15dB-30dB), and its linearity in the low-frequency range of 100Hz to 500Hz is significantly improved. This sound insulation test chamber solves the standing wave interference and sound bridge pollution problems inherent in small chambers, and is suitable for batch comparative testing of prefabricated samples, effectively evaluating the relative differences in sound insulation performance between different samples. Furthermore, compared to existing small sound insulation test chambers made by welding steel metal sheets, this application uses a hardenable slurry material for integral casting, resulting in lower material costs and eliminating the need for complex metal processing and welding processes, reducing manufacturing costs by more than 50%. The frustum-shaped inner cavity design also makes demolding after casting easier, reducing construction difficulty while improving acoustic performance. The design of the sample frame 223 allows for quick sample replacement by direct insertion and removal, eliminating the need for adhesives or disassembling fasteners, significantly improving the efficiency of batch sample comparative testing.

[0070] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sound insulation testing box, characterized in that, The enclosure includes a housing (100) and a top cover (200). The housing (100) includes an outer housing (110), an inner housing (120), and a sound-absorbing layer (130). The inner housing (120) is disposed inside the outer housing (110). The sound-absorbing material is filled between the outer housing (110) and the inner housing (120) to form the sound-absorbing layer (130). The top cover (200) is disposed at the upper opening of the housing (100). Both the outer box (110) and the inner box (120) are integrally cast from a hardenable slurry material, and the wall thickness of the outer box (110) is greater than the wall thickness of the inner box (120). Damping structures are provided on the walls of the outer box (110) and the inner box (120), respectively. The damping structures are formed by the template retained during casting and molding, and the template is tightly bonded to the hardenable slurry material. The top cover plate (200) is provided with a sample frame (223), which is used to install the sample to be tested (400).

2. The sound insulation test chamber according to claim 1, characterized in that, Both the outer box (110) and the inner box (120) are shell structures, and the upper dimensions of the outer box (110) and the inner box (120) are larger than the lower dimensions.

3. The sound insulation test chamber according to claim 2, characterized in that, Both the outer box (110) and the inner box (120) are inverted truncated pyramid shapes.

4. The sound insulation test chamber according to claim 2, characterized in that, The angle between the side wall of the outer box (110) and the vertical direction is different from the angle between the side wall of the inner box (120) and the vertical direction.

5. The sound insulation test chamber according to any one of claims 1 to 4, characterized in that, The wall thickness of the outer box (110) is more than twice the wall thickness of the inner box (120).

6. The sound insulation test chamber according to any one of claims 1 to 4, characterized in that, The damping structure includes a first constraint damping layer attached to the outer side of the wall of the outer box (110), a second constraint damping layer attached to the inner side of the wall of the outer box (110), a third constraint damping layer attached to the outer side of the wall of the inner box (120), and a fourth constraint damping layer attached to the inner side of the wall of the inner box (120).

7. The sound insulation test chamber according to any one of claims 1 to 4, characterized in that, The top cover plate (200) includes an inner cover (210), an outer cover (220), and an intermediate layer (230). The inner cover (210) is located at the upper opening of the inner box (120). The outer cover (220) is located above the inner cover (210). The intermediate layer (230) is located between the inner cover (210) and the outer cover (220). The outer cover (220) is provided with the sample frame (223). The inner cover (210) is provided with a first clearance hole (211) at the position corresponding to the sample frame (223). The intermediate layer (230) is provided with a second clearance hole (231) at the position corresponding to the sample frame (223). The inner wall of the second clearance hole (231) is provided with a sealing strip (232).

8. The sound insulation test chamber according to claim 7, characterized in that, The outer cover (220) includes a rigid layer and a flexible layer, which are alternately stacked along the thickness direction of the outer cover (220).

9. The sound insulation test chamber according to claim 8, characterized in that, The rigid layer is a mortar layer (221), and the flexible layer is a rubber layer (222).

10. The sound insulation test chamber according to claim 7, characterized in that, The intermediate layer (230) is in contact with the sound-absorbing layer (130).

11. The sound insulation test chamber according to any one of claims 1 to 4, characterized in that, A support member (111) is provided between the outer box (110) and the inner box (120), and the support member (111) is supported between the bottom outer side of the inner box (120) and the bottom inner side of the outer box (110).

12. The sound insulation test chamber according to claim 11, characterized in that, The support member (111) is an elastic support member.

13. The sound insulation test chamber according to any one of claims 1 to 4, characterized in that, The gap between the inner wall of the sample frame (223) and the sample to be tested (400) is filled with a flexible sealing material; And / or, a flexible damping material layer is provided on the bottom support surface of the sample frame (223).

14. The sound insulation test chamber according to any one of claims 1 to 4, characterized in that, It also includes a sound level meter (300) and a suspension assembly, the suspension assembly comprising multiple flexible elastic ropes (310), the sound level meter (300) being suspended by the flexible elastic ropes (310) in the central region of the inner housing (120).

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