A resonance structure and silencer composed of the same

Abstract

The present invention provides a resonance structure and a silencer composed of the same, wherein the resonance structure includes surrounding sealing plates, internal side resonance plates and two side surface resonance plates, the internal side resonance plates are at least one group, and the setting direction is consistent with the sound propagation direction; the two side surface resonance plates are composed of microporous sound absorbing plates, and / or panels, and / or perforated plates. The silencer containing the resonance structure can greatly improve the low-frequency and high-frequency sound absorbing effects and broaden the frequency band of sound absorbing while ensuring that the mid-frequency sound absorbing effect meets the requirements; resistive sound absorbing materials can also be filled in the resonance structure as needed to further improve the high-frequency and mid-frequency sound absorbing effects; in addition, the applicability of different sound absorbing frequencies can be improved by adjusting the internal structure of the resonance structure.

Description

Technical Field

[0001] The invention belongs to the technical field of mufflers, and in particular relates to a resonant structure with good full-frequency muffler effect, especially good low-frequency and high-frequency effects and a wide muffler frequency band, and a muffler composed thereof. Background Art

[0002] In the prior art, common silencers can be roughly divided into resistive silencers, reactive silencers, impedance composite silencers, etc. according to their silencer principles and structures. Among them, resistive silencers are the most widely used in actual engineering ventilation noise reduction systems because they have the advantages of good mid-frequency silencer performance and wide mid-frequency silencer bandwidth. Resistive silencers are usually divided into matrix silencers and plate silencers according to their structures. Their main structure is a metal perforated plate with a resistive sound-absorbing material such as glass wool filled inside the perforated plate. The silencer principle is to use the sound energy to be converted into heat energy and dissipated due to friction when sound waves propagate in the resistive sound-absorbing material, thereby achieving the purpose of silencer.

[0003] The installation of resistive silencers is very common in practical engineering applications. At present, resistive silencers use fiber-type porous sound-absorbing materials such as glass wool to fill the outer orifice plate to achieve the purpose of noise reduction. Due to the good sound absorption characteristics of resistive materials such as porous sound-absorbing materials in high-frequency sound absorption, the typical noise reduction characteristics of this type of silencer are good mid-frequency noise reduction performance. However, due to the low sound absorption characteristics of resistive sound-absorbing materials, the low-frequency noise reduction performance of resistive silencers is weak, far lower than the mid-frequency noise reduction. Although the low-frequency performance can be increased to a certain extent by increasing the length of the silencer and increasing the thickness of the sheet to reduce the flow rate, the improvement effect is not obvious, and the economic cost is higher and the resistance coefficient of the silencer is larger. In actual use, for noise sources with more prominent low frequencies, the noise reduction of resistive silencers is difficult to meet the requirements. In addition, the noise reduction performance of resistive silencers will also decrease significantly at higher frequencies, and the high-frequency noise reduction performance is not good. Therefore, in the actual use of resistive silencers, there are currently insufficient low-frequency and high-frequency noise reduction and excessive mid-frequency noise reduction.

[0004] Resistant silencers use changes in the silencer structure to achieve sound attenuation and noise reduction. However, for lower frequency silencers, the silencer needs to be larger in size, and this type of silencer has a narrow sound attenuation frequency band and can only reduce noise at certain specific frequencies. Therefore, the application of reactive silencers is greatly limited in actual use. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a resonance structure and a silencer composed of the structure, which has good low-frequency and high-frequency silencing effects, meets the requirements of medium-frequency silencing effects, and has a wide silencing frequency band.

[0006] The present invention is realized by the following technical scheme: a resonance structure, including surrounding sealing plates, internal side resonance plates, and two side surface resonance plates; the two side surface resonance plates are composed of microporous sound absorbing plates, and / or panels, and / or perforated plates.

[0007] The internal side resonance plates are at least one group, each group includes at least two internal side resonance plates, the internal side resonance plates are arranged in parallel, and the arrangement direction is consistent with the sound propagation direction; the three sides of each internal side resonance plate are connected to the surrounding sealing plates, and together with the surrounding sealing plates form a closed structure, and the other side of the internal side resonance plate is not connected to the surrounding sealing plates, thereby forming an open resonance structure in the resonance structure.

[0008] Optionally, the internal side resonance plate can be arranged on the left side of the resonance structure, or on the right side of the resonance structure, or on both the left and right sides; the length of the internal side resonance plate on the left and / or right side and the width of the cavity can be the same or different.

[0009] Furthermore, the inner side resonance plate is a hard plate; the hard plate of the inner side resonance plate may be a metal plate, a wooden plate, a plastic plate or other hard plate.

[0010] The length of the internal side resonance plate is L1, and the upper limit of the length L1 of the internal side resonance plate is 4m, preferably 3m, 2m, 1m, 0.5m, 0.2m, and the lower limit of the length L1 of the internal side resonance plate is 0.1m, preferably 0.2m, 0.4m, 0.6m, 0.8m, 1m, 1.5m, 2m. The length L1 of the internal side resonance plate determines the resonance frequency, that is, L1 corresponds to the n / 4 wavelength of the resonance frequency, L1=λ*n / 4, wherein λ is the wavelength, n is an odd number, λ= c⁄f, wherein c is the propagation speed of sound waves in the air, which is approximately 340m / s under standard atmospheric pressure and 15°C, and f is the resonance frequency. Therefore, the resonance frequency corresponding to the internal side resonance plate L1 is: f=c*n / (4*L1), when n=1, it corresponds to the lowest resonance sound-absorbing frequency of the structure.

[0011] For example, when the internal side resonance plate L1=0.5m, the corresponding lowest resonance frequency is f=c / (4*L1)=340 / (0.5*4)= 170 Hz, and the structure has a sound absorption peak near the low frequency of 170 Hz.

[0012] A cavity is formed between the parallel internal side resonance plates, and the width of the cavity is d1. The upper limit of the width d1 of the cavity is 400 mm, preferably 300 mm, 250 mm, 200 mm, 150 mm, and 100 mm. The lower limit of the width d1 of the cavity is 10 mm, preferably 20 mm, 40 mm, 80 mm, 100 mm, 150 mm, and 200 mm. The width of the cavity determines the size of the sound absorption peak corresponding to the resonance frequency. The larger d1 is, the larger the sound absorption peak is.

[0013] Furthermore, the microporous sound absorbing panels, and / or panels, and / or perforated panels in the two side surface resonance panels are spliced ​​and connected to form the two side surface resonance panels.

[0014] Furthermore, the microporous sound absorbing plate may be a particle sound absorbing plate, a microperforated plate, a foam aluminum plate or other microporous structure plate, and a microporous structure exists inside the microporous sound absorbing plate.

[0015] Furthermore, the panel is a hard plate; the hard plate of the panel can be a metal plate, a wooden plate, a plastic plate or other hard plate.

[0016] The length of the microporous sound absorbing board is L2, and the upper limit of the length L2 of the microporous sound absorbing board is 4m, preferably 3m, 2m, 1m, 0.5m, 0.2m, and the lower limit of the length L1 of the microporous sound absorbing board is 0.1m, preferably 0.2m, 0.4m, 0.6m, 0.8m, 1m, 1.5m, 2m. The length L2 of the surface microporous sound absorbing board determines the resonance frequency of the low frequency. The smaller the L2 size, the lower the corresponding resonance frequency, the better the low-frequency sound-absorbing performance, but the mid-high frequency sound-absorbing performance will be slightly reduced. On the contrary, the larger the L2 size, the higher the resonance frequency, the slightly worse the low-frequency sound-absorbing performance, but the better the mid-high frequency sound-absorbing performance. When the L2 size is the largest, it covers the entire outer surface.

[0017] Optionally, the inner side of the resonance plates on both sides is filled with a resistive sound absorbing material, and the upper limit of the width d2 of the resistive sound absorbing material is 200 mm, more preferably 150 mm, or 100 mm, or 50 mm; the lower limit of the width d2 of the resistive sound absorbing material is 5 mm, more preferably 10 mm, or 20 mm, or 50 mm. Different widths d2 of resistive sound absorbing materials correspond to different sound absorbing effects and can be adjusted as needed.

[0018] By designing L1, L2, d1, and d2 that match each other, a specific noise reduction structure for noises of different frequencies can be obtained.

[0019] The present invention also provides another technical solution, specifically: a muffler, the muffler includes the above-mentioned resonance structure, the resonance structure can be one section or multiple sections; when the resonance structure is multiple sections, the multiple sections of the resonance structure are connected in sequence, and the resonance structures of each section can be the same or different. When the multiple sections of the resonance structure are connected in sequence, the muffler effect can be further adjusted and improved.

[0020] Furthermore, the resonant structure has two sections, three sections or four sections.

[0021] The beneficial effects of the present invention are as follows: first, the internal side resonance plate of the present invention is different from the sound-absorbing principle of the vibration plate in the prior art, such as CN2020106263650, or the resonance plate with the outer side filled with sound-absorbing material, such as CN201320705567X. The former vibration plate is only fixed on one side in contact with the sealing plate, and the vibration of the vibration plate is used to assist the sound absorption. The latter resonance plate is not connected to the surrounding sealing plates, etc., while the three sides of the internal side resonance plate of the present invention are fixed in contact with the sealing plate, and then the closed cavity formed between a group of resonance plates or multiple groups of resonance plates is used to achieve sound absorption. When the sound wave is incident, the low-frequency sound wave is longer and diffracts into the cavity to vibrate and consume its energy. Therefore, it has better low-frequency noise reduction performance. Of course, it is also different from the structure and effect of different length sound-absorbing tubes in the prior art, such as CN2019109046376. Furthermore, the setting direction of the internal side resonance plate of the present invention is the same as the sound propagation direction. Secondly, the present invention further combines the internal side resonance plate with the surface resonance plate, giving full play to the advantages of the resonance structure formed by the internal side resonance plate in the high low-frequency sound absorption peak value and narrow sound absorption frequency band, and the resonance structure formed by the surface resonance plate in the wide low-frequency sound absorption frequency band and relatively low peak value, not only taking into account the advantages of the two resonance structures, achieving better low-frequency sound absorption performance, but also achieving an effect that is significantly better than the two structures, and the synergistic effect is obvious. Thirdly, the sound absorption unit disclosed in the prior art CN2018209915067, although using a surface perforated plate, or a combination of a surface perforated plate and a panel, has achieved certain effects, but its more improvements lie in the design of the internal channel structure, and the internal side resonance plate is not used. The present invention can also improve the sound absorption effect of the surface resonance plate after the surface resonance plate is combined with the internal side resonance plate. In the prior art, there is no technical solution for combining the internal side resonance plate, the two side surface resonance plates, and the resistive sound absorbing material, and no technical inspiration is given for achieving good low-frequency, medium-frequency, and high-frequency sound absorption effects after the combination.

[0022] In general, compared with the existing technology, it has the following advantages:

[0023] 1) Compared with the existing resistive ventilation silencer, the resonance structure of the present invention can effectively improve the low-frequency and high-frequency sound-absorbing performance, especially the low-frequency and high-frequency performance is better, and the sound-absorbing frequency band is widened; compared with the resonance structure composed of a single internal side resonance plate and the resonance structure composed of a surface resonance plate, the low-frequency, medium-frequency and high-frequency sound-absorbing performance are all better.

[0024] 2) By selectively filling the resonant structure with resistive sound absorbing materials, the high-frequency and mid-frequency noise reduction effects can be further improved.

[0025] 3) For different noise sources, by designing the internal structure of the muffler, such as adjusting the number of groups of resonance structures in the muffler, or using resonance structures of different structures in the same muffler, or adjusting and matching the length L1 of the internal side resonance plate in the resonance structure, the length L2 of the microporous sound absorbing plate, the cavity width d1, the width d2 of the resistive sound absorbing material, etc., customized designs can be made for different noise reduction requirements to meet the use of different scenarios, greatly improving the applicability of the muffler. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a resonance structure diagram Figure 1 ;

[0027] Figure 2 This is a resonance structure diagram Figure 2 (Top view);

[0028] Figure 3 It is a schematic diagram of the resistive sound absorbing material filled in the resonant structure (the internal side resonance plate is on the left);

[0029] Figure 4 It is a schematic diagram of the resistive sound absorbing material filled in the resonant structure (the internal side resonance plate is on the right);

[0030] Figure 5 It is a schematic diagram of a muffler 1 composed of three-section resonance structures;

[0031] Figure 6 This is the test result of muffler 1 which consists of three-section resonance structure.

[0032] Figure 7 It is a schematic diagram of a muffler 2 composed of three-section resonance structures;

[0033] Figure 8 This is the test result of muffler 2 which consists of a three-section resonance structure.

[0034] In the figure: 1- surrounding sealing plates, 2- internal side resonance plates, 3- microporous sound absorbing plates, 4- panel plates, 5- resistive sound absorbing materials, 6- perforated plates. DETAILED DESCRIPTION

[0035] like Figure 1-2As shown, a resonance structure includes a surrounding sealing plate 1, an internal side resonance plate 2, and a surface resonance plate, wherein the surface resonance plate includes a microporous sound absorbing plate 3 and a panel 4, wherein the length of the internal side resonance plate is L1, the length of the microporous sound absorbing plate is L2, and the width between the two internal side resonance plates is d1; the length L1 of the internal side resonance plate is different from the length L2 of the microporous sound absorbing plate, wherein: Figure 1 The length of L1 is longer. Figure 2 The length of L2 is longer. By adjusting L1, L2 and d1, customized designs can be made for different silencer requirements to meet the use of different scenarios, which greatly improves the applicability of the silencer. Among them, L1 and L2 affect the frequency, and d1 affects the peak value.

[0036] like Figure 3-4 As shown, it further includes a resistive sound absorbing material 5 arranged in the resonance structure. Filling the resistive sound absorbing material between the internal side resonance plate and the two side surface resonance plates can further improve the sound attenuation of the full frequency band. In this embodiment, the resistive sound absorbing material 5 is specifically arranged on the inner side of the surface resonance plate. The width of the resistive sound absorbing material 5 is d2, and d2 is the distance between the internal side resonance plate and the surface resonance plate. In practical applications, the d2 can be adjusted according to the actual sound attenuation requirements, especially the mid-frequency sound attenuation requirements. The internal side resonance plate can be arranged on the left side or on the right side. In addition, multiple internal side resonance plates can be arranged inside the resonance structure to increase the sound attenuation of the low frequency.

[0037] like Figure 5 As shown, a silencer is composed of three resonance structures connected in sequence. The specific structures of the first two resonance structures are similar, both of which include a group of surrounding sealing plates 1, internal side resonance plates 2 and two side surface resonance plates, wherein the two side surface resonance plates are microporous sound absorbing plates 3 and surface perforated plates 6, and the third resonance structure is provided with an internal side resonance plate 2, and the surface resonance plate is a perforated plate 6, and the above resonance structures are filled with resistive sound absorbing material 5.

[0038] The material of the internal side resonance plate is steel plate, the material of the surrounding sealing plates is steel plate, the material of the microporous sound absorption plates in the first two resonance structures is a particle sound absorption plate, the panel is a metal perforated plate, the material of the perforated plate in the third section is a metal perforated plate, and the material of the resistive sound absorption material is glass wool.

[0039] The length of the resonance plate is set differently to broaden the low-frequency sound absorption band. The muffler is 3m long, the length of each resonance structure is 1m, and the muffler flow rate is 50%; wherein, in the first resonance structure, the length L1 of the internal side resonance plate is 0.6m, the length L2 of the microporous sound absorption plate is 0.4m, the length of the surface hole plate is 0.6m, the cavity width d1 is 150mm, and the width d2 of the resistive sound absorption material is 25mm; in the second resonance structure, the length L1 of the internal side resonance plate is 0.4m, the length L2 of the microporous sound absorption plate is 0.6m, the length of the surface hole plate is 0.4m, the cavity width d1 is 100mm, and the width d2 of the resistive sound absorption material is 50mm; in the third resonance structure, the length L1 of the internal side resonance plate is 0.4m, the cavity width d1 is 50mm, the width d2 of the resistive sound absorption material is 75mm, the perforation rate of the perforated plates on both sides is 25%, and the aperture is 3mm.

[0040] in, Figure 6 The comparison data of laboratory test results of the above-mentioned silencer of the present invention and the sheet silencer in the prior art, whose main structure is a metal perforated plate on the surface and glass wool resistive sound absorbing material is filled inside the perforated plate, under the same test conditions are shown. According to the test results, the silencer of the present invention has a significant improvement in the silencing performance below low frequencies of 200Hz, and the improvement is basically around 4dB. In the high-frequency range, the improvement of the new silencer is more obvious. Since the current resistive silencer has excess silencing in the mid-frequency range, the reduction in the silencing performance of the silencer in certain mid-frequency bands does not affect the actual use, and it can even be said to be more in line with actual needs.

[0041] like Figure 7 As shown, a silencer is composed of three sections of resonance structures connected in sequence. The specific structures of the first two sections of resonance structures are similar, both of which include a group of surrounding sealing plates 1, internal side resonance plates 2 and two side surface resonance plates, wherein the two side surface resonance plates are microporous sound absorbing plates 3, and two groups of internal side resonance plates 2 are arranged in the third section of the resonance structure, and the surface resonance plates are perforated plates 6, and the above resonance structures are filled with resistive sound absorbing materials 5.

[0042] The material of the internal side resonance plate is steel plate, the material of the surrounding sealing plates is steel plate, the material of the microporous sound absorption plates in the first two resonance structures is particle sound absorption plates, the material of the perforated plate in the third section is metal perforated plate, and the material of the resistive sound absorption material is glass wool.

[0043] The length of the resonance plate is set differently to broaden the low-frequency sound absorption band. The muffler is 3m long, the length of each resonance structure is 1m, and the muffler flow rate is 50%; wherein, in the first resonance structure, the length L1 of the internal side resonance plate is 0.6m, the length L2 of the microporous sound absorbing plate is 1m, the cavity width d1 is 150mm, and the width d2 of the resistive sound absorbing material is 25mm; in the second resonance structure, the length L1 of the internal side resonance plate is 0.4m, the length L2 of the microporous sound absorbing plate is 1m, the cavity width d1 is 150mm, and the width d2 of the resistive sound absorbing material is 25mm; in the third resonance structure, the length L1 of the internal side resonance plate is 0.5m, L1' is 0.28m, the cavity width d1 is 100mm, the width d2 of the resistive sound absorbing material is 50mm, the perforation rate of the perforated plates on both sides is 25%, and the aperture is 3mm.

[0044] in, Figure 8 The comparison data of laboratory test results of the above-mentioned silencer of the present invention and the sheet silencer in the prior art, whose main structure is a metal perforated plate on the surface and glass wool resistive sound absorbing material is filled inside the perforated plate, under the same test conditions are shown. According to the test results, the silencer performance of the silencer of the present invention is significantly improved at low frequencies below 250Hz, and the improvement is basically more than 5dB, and some low frequencies reach 10dB. In the high frequency range, the improvement of the new silencer is more obvious. Since the current resistive silencer has excess sound attenuation at medium frequencies, the reduction of the sound attenuation of the silencer in certain frequency bands of the medium frequencies does not affect the actual use, and it can even be said to be more in line with actual needs.

[0045] In summary, compared with the original sheet-type muffler, the muffler of the present invention significantly improves the low-frequency and high-frequency sound-absorbing performance, broadens the sound-absorbing frequency band, and has obvious advantages over the existing technical solutions. The present invention provides a muffler with a higher cost-effectiveness and a wider range of applications. In addition, the muffler formed by combining the internal side resonance plate to form an internal side resonance structure and the surface resonance plate to form a surface resonance structure, especially the muffler formed by the combination of different forms, has a wider low-frequency sound-absorbing frequency band, a larger sound-absorbing amount, and better high-frequency sound-absorbing performance than the internal side resonance structure or the surface resonance structure alone.

Claims

1. A resonant structure, characterized in that: It includes surrounding sealing plates, internal side resonance plates, and two side surface resonance plates; the two side surface resonance plates are composed of microporous sound absorbing plates, or microporous sound absorbing plates and panels, or microporous sound absorbing plates and perforated plates; the internal side resonance plates are at least one group, each group includes two parallel internal side resonance plates, and the setting direction is consistent with the sound propagation direction; wherein, the length of the internal side resonance plate is L1, ranging from 0.1m to 4m, the length of the microporous sound absorbing plate is L2, and the length of the internal side resonance plate L1 is different from the length of the microporous sound absorbing plate L2; a cavity is formed between the parallel internal side resonance plates, and the width of the cavity is d1, ranging from 10mm to 400mm; the resonance frequency corresponding to the length L1 of the internal side resonance plate is: f=c*n / (4*L1), c is the propagation speed of sound waves in air, f is the resonance frequency, and n is an odd number.

2. The resonant structure according to claim 1, characterized in that: The three sides of the internal side resonance plate are connected to the surrounding sealing plates and together form a closed structure, while the other side of the internal side resonance plate is not connected to the surrounding sealing plates, thereby forming an open resonance structure within the resonance structure.

3. The resonant structure according to claim 2, characterized in that: The inner side resonance plate is one of a metal plate, a wooden plate, a plastic plate and a cement plate.

4. The resonant structure according to claim 1, characterized in that: The microporous sound absorbing plate and the panel, or the microporous sound absorbing plate and the perforated plate in the two-side surface resonance plate are spliced ​​and connected to form the two-side surface resonance plate.

5. The resonant structure according to claim 4, characterized in that: The microporous sound absorbing plate is a particle sound absorbing plate, a microperforated plate or a foam aluminum plate, and a microporous structure exists inside the microporous sound absorbing plate.

6. The resonant structure according to claim 5, characterized in that: The upper limit of the length L2 of the microporous sound absorbing plate is 4 m.

7. The resonant structure according to claim 1, characterized in that: The panel is a metal plate, a wooden plate or a plastic plate.

8. The resonant structure according to claim 1, characterized in that: The perforated plate is a metal perforated plate, a wooden perforated plate or a gypsum perforated plate.

9. The resonant structure according to claim 8, characterized in that: The perforation rate of the perforated plate is greater than 15%, and the hole diameter is greater than 1 mm.

10. The resonant structure according to any one of claims 1-2, 4-9, characterized in that: The inner sides of the two side surface resonance plates are filled with resistive sound absorbing material, and the width of the resistive sound absorbing material is d2.

11. The resonant structure according to claim 10, characterized in that: The width d2 of the resistive sound absorbing material is less than 200 mm.

12. The resonant structure according to any one of claims 1-2, 4-9, characterized in that: The inner side resonance plate is arranged on the left side of the resonance structure, or on the right side of the resonance structure, or on both the left side and the right side.

13. The resonant structure according to claim 12, characterized in that: The length L1 of the inner side resonator plate on the left and / or right side and the width d1 of the cavity may be the same or different.

14. A muffler, comprising the resonant structure according to any one of claims 1 to 13, characterized in that: The resonance structure is one section or multiple sections. When the resonance structure is multiple sections, the multiple sections of the resonance structure are connected in sequence. The resonance structures of each section are the same or different.

15. The muffler according to claim 14, characterized in that The resonance structure has two sections, three sections or four sections.

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