Internal side resonance structure and muffler composed of the same

Abstract

The present invention provides an internal side resonance structure and a silencer composed of the same, wherein the internal side resonance structure includes surrounding sealing plates, two side perforated plates and an internal side resonance plate, the internal side resonance plate is at least one group, and the setting 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 structure in the internal side resonance structure. The silencer including the internal side resonance structure can improve the low-frequency silencer effect while ensuring that the mid-frequency silencer effect meets the requirements; resistive sound absorbing materials can also be filled on the outside of the internal side resonance plate as needed to improve the high-frequency and mid-frequency silencer effects; in addition, the applicability of different silencer frequencies can be improved by adjusting the internal structure of the internal side resonance structure.

Description

Technical Field

[0001] The invention belongs to the technical field of mufflers, and in particular relates to an internal side resonance structure with good low-frequency muffler effect and satisfactory medium-frequency muffler effect and a muffler composed of the structure. 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 deficiencies in the prior art, the present invention provides an internal side resonance structure and a silencer composed of the structure, which has good low-frequency and high-frequency silencing effects and meets the requirements for medium-frequency silencing effects.

[0006] The present invention is achieved through the following technical scheme: an internal side resonance structure, including surrounding sealing plates, two side perforated plates and an internal side resonance plate, the internal side resonance plate is 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, the other side of the internal side resonance plate is not connected to the surrounding sealing plates, thereby forming an open structure in the internal side resonance structure; the internal side resonance plate is a hard plate.

[0007] Optionally, the internal side resonance plate can be arranged on the left side of the internal side resonance structure, or on the right side of the internal side 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.

[0008] Furthermore, the hard plate material may be one of a metal plate, a wooden plate, a plastic plate, and a cement plate.

[0009] Furthermore, the perforated plates on both sides may be one of metal perforated plates, wooden perforated plates and gypsum perforated plates. The perforation rate of the perforated plates on both sides is greater than 15%, and the hole diameter is greater than 1 mm.

[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 170Hz.

[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] By designing L1 and d1 to match each other, a specific noise elimination structure for noises of different frequencies can be obtained.

[0014] Optionally, the outer side of the inner side resonance plate 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.

[0015] The present invention also provides another technical solution, specifically: a muffler, the muffler includes the above-mentioned internal side resonance structure, the internal side resonance structure can be one section or multiple sections; when the internal side resonance structure is multiple sections, the multiple sections of the internal side resonance structure are connected in sequence, and the internal side resonance structures of each section can be the same or different. When the multiple sections of the internal side resonance structure are connected in sequence, the muffler effect can be further adjusted and improved.

[0016] Furthermore, the internal side-type resonance structure has two sections, three sections or four sections.

[0017] The beneficial effects of the present invention are as follows: the present invention is different from the prior art in that the vibration plate such as CN2020106263650 or the sound absorbing material filled on the outside of the resonance plate such as CN201320705567X is used for silencing. The former, such as the vibration plate, has only one side in contact with the sealing plate, and the vibration of the vibration plate is used to assist in silencing. The latter resonance plate is not connected to the surrounding sealing plates, while the present invention has three sides in contact with the sealing plate. Specifically, the silencing principle of the present invention is to use a closed cavity formed between a group of resonance plates or between multiple groups of resonance plates to achieve silencing. 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 such as CN2019109046376 in the prior art. Further, the setting direction of the internal side resonance plate of the present invention is the same as the sound propagation direction, and the internal side resonance structure has practical significance for low-frequency silencing. In general, compared with the prior art, it has the following advantages:

[0018] 1) Compared with the existing resistive ventilation silencer, the internal side resonance structure is set up to effectively improve the low-frequency silencer performance, the low-frequency performance is better, and ensure that the mid-frequency silencer performance meets the requirements.

[0019] 2) The high-frequency and mid-frequency sound absorption effects can be further improved by selectively filling the internal side resonance structure with resistive sound absorbing materials.

[0020] 3) For different noise sources, by designing the internal structure of the muffler, such as adjusting the number of groups of internal side resonance structures in the muffler, or using internal side resonance structures of different structures in the same muffler, or adjusting and matching the length L1 of the internal side resonance plate in the internal side resonance structure, 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

[0021] Figure 1 It is a schematic diagram of the internal side resonance structure;

[0022] Figure 2 It is a schematic diagram of a group of internal side resonance plates arranged in an internal side resonance structure;

[0023] Figure 3 It is a schematic diagram of two sets of internal side resonance plates arranged in an internal side resonance structure;

[0024] Figure 4 It is a schematic diagram of the outer side of the internal side resonance plate filled with resistive sound absorbing material;

[0025] Figure 5 It is a schematic diagram of a muffler consisting of three sections of internal side resonance structures;

[0026] Figure 6 It is the test result of the muffler composed of three sections of internal side resonance structure.

[0027] In the figure: 1- surrounding sealing plates, 2- perforated plates on both sides, 3- internal side resonance plates, 3'- internal side resonance plates, 4- resistive sound absorbing material. DETAILED DESCRIPTION

[0028] like Figure 1-2As shown, an internal side resonance structure includes surrounding sealing plates 1, two side perforated plates 2 and an internal side resonance plate 3, wherein the internal side resonance plates are a group, including two opposite internal side resonance plates, and the setting direction is consistent with the sound propagation direction; the three sides of each internal side resonance plate 3 are connected to the surrounding sealing plates 1, and together with the surrounding sealing plates 1 form a closed structure, and the other side of the internal side resonance plate 3 is not connected to the surrounding sealing plates 1, thereby forming an open structure in the internal side resonance structure; the internal side resonance plate 3 is a hard plate; wherein the length of the internal side resonance plate is L1, and a cavity is formed between the parallel internal side resonance plates, and the width of the cavity is d1.

[0029] like Figure 3 As shown, it further comprises a second set of inner side resonance panels 3'.

[0030] like Figure 4 As shown, it further includes a resistive sound absorbing material 4 arranged on the outer side of the inner side resonance plate, and the width of the resistive sound absorbing material 4 is d2.

[0031] like Figure 5 As shown, a muffler is composed of three sections of internal side resonance structures, a group of internal side resonance plates is arranged in the first section of the internal side resonance structure, and two groups of internal side resonance plates are respectively arranged in the latter two sections of the internal side resonance structure, and the outer sides of the internal side resonance plates are filled with resistive sound-absorbing materials, the material of the internal side resonance plates is steel plates, the material of the surrounding sealing plates is steel plates, the material of the perforated plates on both sides is metal perforated plates, and the material of the resistive sound-absorbing material is glass wool; the lengths of the internal side resonance plates are set to be different to broaden the low-frequency sound-absorbing band, the length of the muffler is 3m, the length of each section of the internal side resonance structure is 1m, and the muffler flow rate is 50%; wherein, In the first section of the internal side resonance structure, the length L1 of the internal side resonance plate is 0.9m, the cavity width d1 is 150mm, and the width d2 of the resistive sound absorbing material is 25mm; in the second section of the internal side resonance structure, the length L1 of the internal side resonance plate is 0.45m, L1' is 0.45m, the cavity width d1 is 150mm, and the width d2 of the resistive sound absorbing material is 25mm; in the third section of the internal side resonance structure, the length L1 of the internal side resonance plate is 0.55m, L1' is 0.28m, the cavity width d1 is 100mm, and the width d2 of the resistive sound absorbing material is 50mm; the perforation rate of the perforated plates on both sides is 23%, and the aperture is 3mm.

[0032] in, Figure 6The above-mentioned silencer of the present invention is shown, and the comparison data of the laboratory test results under the same test conditions are shown, with the main structure of the sheet silencer in the prior art being a metal perforated plate on the surface and glass wool resistive sound absorbing material filled inside the perforated plate. According to the test results, compared with the sheet silencer in the prior art, the intermediate frequency has a certain decrease, which is because the use of resistive sound absorbing material is reduced in the internal side-type resonance silencer, and the reduction is 66.7%. The reason for reducing the amount of resistive sound absorbing material is that the existing resistive silencer has a waste of sound attenuation in the intermediate frequency; the silencer of the present invention has improved sound attenuation performance below 200Hz at low frequencies, and the improvement in some frequency bands is more than 5dB. Since it is more difficult to improve the low-frequency performance, the 5dB performance improvement has great practical significance for low-frequency sound attenuation. In addition, due to the filling of a small amount of resistive sound absorbing material, the performance of the silencer in the high-frequency range is also improved. If the amount of resistive sound absorbing material is increased, the intermediate frequency of the silencer of the present invention will also be improved accordingly, and the performance is also better than the existing sheet silencer.

Claims

1. An internal side resonance structure, characterized in that: It includes surrounding sealing plates, two side perforated plates and internal side resonance plates, wherein the internal side resonance plates are one group or multiple groups, and the setting direction is consistent with the sound propagation direction; the three sides of each internal side resonance plate are fixedly connected to the surrounding sealing plates, and the other side of the internal side resonance plate is not connected to the surrounding sealing plates, thereby forming an open structure in the internal side resonance structure; wherein the length of the internal side resonance plate is L1, ranging from 0.1m-4m; a cavity is formed between the internal side resonance plates, and the width of the cavity is d1, ranging from 10mm-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 the air, f is the resonance frequency, and n is an odd number.

2. An internal side resonance structure according to claim 1, characterized in that: The inner side resonance plate is a hard plate.

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

4. An internal side resonance structure according to any one of claims 1 to 3, characterized in that: The perforated plates on both sides are one of metal perforated plates, wooden perforated plates and gypsum perforated plates.

5. An internal side resonance structure according to claim 4, characterized in that: The perforation rate of the perforated plates on both sides is greater than 15%, and the hole diameter is greater than 1 mm.

6. An internal side resonance structure according to any one of claims 1 to 3, characterized in that: The outer side of the inner side resonance plate is filled with a resistive sound absorbing material, the width of the resistive sound absorbing material is d2, and the width d2 of the resistive sound absorbing material is less than 200 mm.

7. An internal side resonance structure according to any one of claims 1-3, 5, characterized in that: The inner side resonance plate is arranged on the left side of the inner side resonance structure, or on the right side of the inner side resonance structure, or on both the left and right sides.

8. An internal side resonance structure according to claim 7, characterized in that: The length of the inner side resonator panels on the left and / or right sides and the width of the cavities may be the same or different.

9. A muffler, comprising an internal side resonance structure according to any one of claims 1 to 8, characterized in that: The internal side resonance structure is one section or multiple sections. When the internal side resonance structure is multiple sections, the multiple sections of the internal side resonance structure are connected in sequence, and the internal side resonance structures of each section are the same or different.

10. A muffler according to claim 9, characterized in that: The internal side-type resonance structure has two sections, three sections or four sections.

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