A broadband noise elimination structure based on a coiled cavity

Abstract

The present invention discloses a broadband noise elimination structure based on a coiled cavity, which relates to the field of noise reduction structures. It includes a noise elimination frame, a coiled cavity, an inlet pipe, an outlet pipe, and a local resonance unit. The coiled cavity is arranged inside the noise elimination frame, and the inlet pipe and the outlet pipe are respectively communicated with the upper and lower sides of the coiled cavity. The coiled cavity is divided by a partition plate one and a partition plate two to form an S-shaped channel for sound flow, and the local resonance unit is arranged at some turning corners of the S-shaped channel. The local resonance unit absorbs the noise propagated in the coiled cavity through cavity resonance. The present invention constructs a noise elimination structure with low frequency, broadband, simple structure, light weight and thinness based on the coiled cavity structure.

Description

Technical Field

[0001] The present invention relates to the field of noise reduction structures, and particularly to a broadband noise elimination structure based on a coiled cavity. Background Art

[0002] The control of low-frequency pipeline noise is closely related to people's daily lives and is also a hot and difficult point in recent research. Controlling pipeline noise by installing a muffler has become the most commonly used means.

[0003] Traditional absorption mufflers made of porous and fibrous sound-absorbing materials can effectively absorb medium and high-frequency noise, but have little effect on low-frequency noise. Traditional reactive mufflers mainly include two types: resonant mufflers and expansion chamber mufflers. Resonant mufflers such as Helmholtz mufflers have good suppression performance for low-frequency noise. However, due to the resonant characteristics of the resonator, the muffler only has a noise reduction effect in an extremely narrow frequency band. Therefore, multiple resonators with different resonant frequencies are usually connected in parallel / series to expand the noise reduction bandwidth. Expansion chamber mufflers have good broadband performance, but the frequency characteristics and noise reduction performance mainly depend on the length and expansion ratio of the expansion chamber. Therefore, for low-frequency broadband noise, using a reactive muffler will inevitably increase the volume of the structure, making it large, bulky, and heavy. Summary of the Invention

[0004] The purpose of the present invention is to provide a broadband noise elimination structure based on a coiled cavity to solve the problems of poor noise reduction effect of the muffler and the possible large volume and inconvenient use.

[0005] A broadband noise elimination structure based on a coiled cavity includes a noise elimination frame, a coiled cavity, an inlet pipe, an outlet pipe, and a local resonance unit. The coiled cavity is arranged inside the noise elimination frame, and the inlet pipe and the outlet pipe are respectively connected to the upper and lower sides of the coiled cavity. The coiled cavity is divided by a partition plate one and a partition plate two to form an S-shaped channel for sound flow, and the local resonance unit is arranged at some turning corners of the S-shaped channel. The local resonance unit absorbs the noise propagated in the coiled cavity through cavity resonance.

[0006] Preferably, a plurality of partition plates are evenly distributed at equal intervals on the inner walls on both sides of the coiled cavity, namely the partition plate one and the partition plate two. The partition plate one and the partition plate two are arranged in an interval dislocation structure. There is a sound transmission channel between the end of each partition plate one and the partition plate two and the inner wall of the noise elimination frame, so that an S-shaped channel for sound wave transmission is formed inside the coiled cavity, and the two ends of the S-shaped channel are respectively connected to the inlet pipe and the outlet pipe.

[0007] Preferably, small hole arrays are formed on the surfaces of the spaced-apart first partition plates, and the small hole arrays communicate with the S-shaped channels.

[0008] Preferably, the cross-sectional area of the coiled cavity is 5 times that of the sound inlet pipe and the sound outlet pipe.

[0009] Preferably, the local resonance unit includes an extension plate, a first T-shaped plate, a second T-shaped plate, and a third T-shaped plate. An extension plate is fixedly connected to the ends of two adjacent first partition plates and second partition plates. One side of the vertical portion of the first T-shaped plate faces the extension plate and there is also a sound transmission channel therebetween. The second T-shaped plate and the third T-shaped plate are respectively arranged on the other side of the vertical portion of the first T-shaped plate. There is also a sound transmission channel between the vertical portions of the second T-shaped plate and the third T-shaped plate and the vertical portion of the first T-shaped plate. The horizontal portions of the first T-shaped plate, the second T-shaped plate, and the third T-shaped plate are all fixedly connected to the inner wall of the sound absorption frame. A first resonance cavity is formed between the vertical portions of the second T-shaped plate and the third T-shaped plate and the inner wall of the sound absorption frame.

[0010] Preferably, a partition plate is horizontally and perpendicularly fixedly connected to one side of the first T-shaped plate facing the second T-shaped plate and the third T-shaped plate. The partition plate is fixedly connected to the inner wall of the sound absorption frame and the partition plate penetrates through the first resonance cavity to divide the first resonance cavity into upper and lower cavities with different lengths.

[0011] Preferably, both the sound inlet pipe and the sound outlet pipe are fixedly arranged on the sound absorption frame in an insertion structure. Fixing plates are respectively fixedly connected to both sides of the sound inlet pipe and the sound outlet pipe. A second resonance cavity is formed between the fixing plates and the inner wall of the sound absorption frame.

[0012] Preferably, the sound inlet pipe, the sound outlet pipe, the coiled cavity, the first partition plate, the second partition plate, the extension plate, the first T-shaped plate, the second T-shaped plate, and the third T-shaped plate are made of hard materials such as resin, plastic, or metal. The S-shaped channels, the first resonance cavity, and the second resonance cavity are filled with porous sound absorption materials.

[0013] The present invention has the following advantages:

[0014] When sound waves enter the coiled cavity through the sound inlet pipe, the impedance mismatch caused by the sudden change in the cross-sectional area inside the cavity will reflect the advancing sound waves. Since the S-shaped channel effectively extends the propagation path of the sound waves, the noise reduction ability for low-frequency noise can be greatly improved. Additionally, due to the sound pressure difference existing on both sides of the partition plate one in the S-shaped channel, the sound waves move back and forth on both sides of the perforated plate, and the back-and-forth vibration of the air in the small holes dissipates the sound energy, thus forming a sound absorption effect. Moreover, by using local resonance units, resonance is generated in sequence to achieve sound absorption compensation for frequency bands with poor noise reduction ability, further improving the noise reduction ability at the sound absorption trough, and ultimately achieving the sound absorption effect in the low-frequency and continuous broadband range. The present invention uses a coiled cavity to replace the traditional straight-through cavity, making the structure thinner, lighter, and simpler, overcoming many deficiencies of traditional pipeline sound absorption devices, such as narrow sound absorption frequency bands, large structural volumes, and poor environmental adaptability, and is very easy to be practically applied in different spaces and noise environments. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of the present invention.

[0016] Figure 2 It is a schematic internal structure diagram of the present invention.

[0017] Figure 3 is Figure 2 A schematic structural diagram of the structure at A in the structure shown

[0018] Figure 4 It is a front view of the internal structure of the present invention;

[0019] Figure 5 It is a schematic diagram of the sound flow of the present invention;

[0020] Reference numerals in the drawings: 1, sound absorption frame; 10, sound inlet pipe; 11, sound outlet pipe; 12, coiled cavity; 13, partition plate one; 14, partition plate two; 15, small hole array; 16, S-shaped channel;

[0021] 2, local resonance unit; 20, extension plate; 21, T-shaped plate one; 22, T-shaped plate two; 23, T-shaped plate three; 24, resonance cavity one; 25, fixing plate; 26, partition; 27, resonance cavity two. Detailed Description of the Invention

[0022] The following is a further detailed description of the specific embodiments of the present invention by referring to the drawings and describing the embodiments, so as to help those skilled in the art have a more complete, accurate, and in-depth understanding of the inventive concept and technical solution of the present invention.

[0023] Such as Figures 1-5As shown in the figure, the present invention provides a broadband noise elimination structure based on a coiled cavity, including a noise elimination frame 1, a coiled cavity 12, an inlet pipe 10, an outlet pipe 11, and a local resonance unit 2. The coiled cavity 12 is arranged inside the noise elimination frame 1, and the inlet pipe 10 and the outlet pipe 11 are respectively connected to the upper and lower sides of the coiled cavity 12. Inside the coiled cavity 12, an S-shaped channel 16 for sound flow is formed by means of a first partition plate 13 and a second partition plate 14, and the local resonance unit 2 is arranged at some turning corners of the S-shaped channel 16. The local resonance unit 2 absorbs the noise propagating in the coiled cavity 12 through cavity resonance.

[0024] A plurality of partition plates are evenly distributed at equal intervals on the inner walls on both sides of the coiled cavity 12, namely the first partition plate 13 and the second partition plate 14. The first partition plate 13 and the second partition plate 14 are in an interval dislocation structure. A sound transmission channel is left between the end of each first partition plate 13 and the second partition plate 14 and the inner wall of the noise elimination frame 1 so that an S-shaped channel 16 for sound wave transmission is formed inside the coiled cavity 12. The two ends of the S-shaped channel 16 are respectively connected to the inlet pipe 10 and the outlet pipe 11. Small hole arrays 15 are formed on the surfaces of the spaced first partition plates 13, and the small hole arrays 15 are connected to the S-shaped channel 16. The cross-sectional area of the coiled cavity 12 is 5 times the cross-sectional area of the inlet pipe 10 and the cross-sectional area of the outlet pipe 11.

[0025] The inlet pipe 10 and the outlet pipe 11 are used to connect to the main noise pipeline, and the propagation path of the incident sound wave after entering the coiled cavity 12 is as Figure 5 shown. The coiled cavity 12 is formed with an S-shaped channel 16 by using the first partition plate 13 and the second partition plate 14. The effective length, cross-sectional area, and the number of segments of the S-shaped channel 16 are adjusted according to the noise properties. Small hole arrays 15 are arranged on the first partition plate 13 for constructing the coiled cavity, so that the first partition plate 13 forms a perforated partition plate, forming a perforated plate sound absorption structure with the S-shaped channel 16. Due to the sound pressure difference existing in the S-shaped channel 16 on both sides of the perforated partition plate, the sound wave moves back and forth on both sides of the small hole array 15, and the back-and-forth vibration of the air in the small holes dissipates the sound energy, thus forming a noise elimination effect. Moreover, the S-shaped channel 16 effectively extends the propagation path of the sound wave, so the noise reduction ability for low-frequency noise can be greatly improved.

[0026] The local resonance unit 2 includes an extension plate 20, a first T-shaped plate 21, a second T-shaped plate 22, and a third T-shaped plate 23. An extension plate 20 is fixedly connected to the ends of two adjacent first partition plates 13 and second partition plates 14. One side of the vertical portion of the first T-shaped plate 21 faces the extension plate 20, and there is also a sound transmission channel between them. On the other side of the vertical portion of the first T-shaped plate 21, the second T-shaped plate 22 and the third T-shaped plate 23 are respectively provided. There is also a sound transmission channel between the vertical portions of the second T-shaped plate 22 and the third T-shaped plate 23 and the vertical portion of the first T-shaped plate 21. The horizontal portions of the first T-shaped plate 21, the second T-shaped plate 22, and the third T-shaped plate 23 are all fixedly connected to the inner wall of the sound-absorbing frame 1. There is a first resonance cavity 24 between the vertical portions of the second T-shaped plate 22 and the third T-shaped plate 23 and the inner wall of the sound-absorbing frame 1. A partition plate 26 is horizontally and perpendicularly fixedly connected to one side of the first T-shaped plate 21 facing the second T-shaped plate and the third T-shaped plate 23. The partition plate 26 is fixedly connected to the inner wall of the sound-absorbing frame 1 and penetrates through the first resonance cavity 24 to divide the first resonance cavity 24 into upper and lower two cavities.

[0027] There is a sound transmission channel for the sound wave to flow between the extension plate 20 and the first T-shaped plate 21, avoiding the blockage of the sound in the S-shaped channel 16. There is also a sound transmission channel between the vertical portions of the second T-shaped plate 22 and the third T-shaped plate 23 and the vertical portion of the first T-shaped plate 21. There is a first resonance cavity 24 between the vertical portions of the second T-shaped plate 22 and the third T-shaped plate 23 and the inner wall of the sound-absorbing frame 1. The sound wave flows sequentially into the sound transmission channel between the vertical portions of the second T-shaped plate 22 and the third T-shaped plate 23 and the vertical portion of the first T-shaped plate 21 and the first resonance cavity 24 along the sound transmission channel between the extension plate 20 and the first T-shaped plate, which can also extend the propagation path of the sound wave and effectively absorb the noise. In addition, the sound wave repeatedly impacts the cavity wall of the first resonance cavity 24 in the first resonance cavity 24, generating a dissipation effect on the sound energy. In addition, the partition plate 26 divides the first resonance cavity 24 into two cavities, and the sound wave can enter the upper and lower two cavities of the first resonance cavity 24 at the same time. The upper and lower two cavities can be set to have different lengths, so that the resonance frequencies of the upper and lower two cavities are different. Therefore, the sound absorption effect at different frequencies can be achieved. The sound wave resonates in the sound transmission channel between the extension plate 20 and the first T-shaped plate, the sound transmission channel between the vertical portions of the second T-shaped plate 22 and the third T-shaped plate 23 and the vertical portion of the first T-shaped plate 21, and the first resonance cavity 24. By generating resonance in sequence, the sound absorption compensation for the frequency band with poor noise reduction ability can be realized, the noise reduction ability at the sound absorption trough can be further improved, and finally the sound absorption effect in the low-frequency and continuous broadband range can be achieved.

[0028] The sound inlet pipe 10 and the sound outlet pipe 11 are both fixedly arranged on the muffling frame 1 in an inserted structure. The inlet / outlet pipe is a pipe with a constant cross-section. One end is connected to the noise pipe, and the other end is connected to and partially extends into the coiled cavity, forming an inner inserted pipe structure. Fixing plates 25 are fixedly connected to both sides of the sound inlet pipe 10 and the sound outlet pipe 11, and a second resonance cavity 27 is left between the fixing plates 25 and the inner wall of the muffling frame 1.

[0029] When sound waves enter the coiled cavity through the sound inlet pipe 10, the impedance mismatch caused by the sudden change in the cross-section in the cavity will reflect the advancing sound waves and dissipate the sound energy, thus forming a muffling effect. A second resonance cavity 27 is left between the fixing plates 25 and the inner wall of the muffling frame 1, and the second resonance cavity 27 can also make the sound waves repeatedly impact the cavity wall of the second resonance cavity 27, dissipating the sound energy.

[0030] The sound inlet pipe 10, the sound outlet pipe 11, the coiled cavity 12, the first partition plate 13, the second partition plate 14, the extension plate 20, the first T-shaped plate 21, the second T-shaped plate 22, and the third T-shaped plate 23 are made of hard materials such as resin, plastic, or metal. The S-shaped channel 16, the first resonance cavity 24, and the second resonance cavity 27 are filled with porous sound-absorbing materials to enhance the sound-absorbing effect on sound waves and achieve a stronger noise reduction effect.

[0031] Working principle: When sound waves enter the coiled cavity 12 through the sound inlet pipe 10, the impedance mismatch caused by the sudden change in the cross-sectional area of the cavity will reflect the advancing sound waves, dissipate the sound energy, and thus form a noise reduction effect. The sound waves advance along the S-shaped channel 16 in the coiled cavity 12 and finally flow out from the sound outlet pipe 11. Since the S-shaped channel 16 effectively extends the propagation path of the sound waves, the noise reduction ability for low-frequency noise can be greatly improved. During the flow of the sound waves, a small hole array 15 is provided on the surface of the first partition plate 13. Due to the sound pressure difference on both sides of the first partition plate 13, the sound waves move back and forth on both sides of the first partition plate 13, and the back-and-forth vibration of the air in the small holes also dissipates the sound energy, thus forming a noise reduction effect. In addition, the sound waves flow sequentially into the sound transmission channels between the vertical parts of the second T-shaped plate 22 and the third T-shaped plate 23 and the vertical part of the first T-shaped plate 21 and the resonance cavity 24 along the sound transmission channel between the extension plate 20 and the first T-shaped plate. Due to the acoustic resonance effect, the sound waves repeatedly impact the cavity wall of the resonance cavity 24 in the resonance cavity 24, dissipating the sound energy. The sound waves resonate in the sound transmission channel between the extension plate 20 and the first T-shaped plate, the sound transmission channels between the vertical parts of the second T-shaped plate 22 and the third T-shaped plate 23 and the vertical part of the first T-shaped plate 21, the resonance cavity 24, and the resonance cavity 27. By generating resonance in sequence, the noise reduction compensation for the frequency band with poor noise reduction ability can be realized, the noise reduction ability at the noise reduction trough can be further improved, and finally the noise reduction effect in the low-frequency and continuous broadband range can be achieved. The present invention uses a coiled cavity to replace the traditional straight-through cavity, making the structure thinner, lighter, and simpler, overcoming many deficiencies of the traditional pipeline noise reduction device, such as narrow noise reduction frequency band, large structural volume, and poor environmental adaptability, and is very easy to be practically applied in different spaces and noise environments.

[0032] The present invention has been described exemplarily above in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above-mentioned manner. As long as various non-substantive improvements are made by adopting the inventive concept and technical solution of the present invention, or the inventive concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A broadband noise elimination structure based on a coiled cavity, characterized in that: It includes a sound-absorbing frame (1), a coiled cavity (12), an inlet pipe (10), an outlet pipe (11), and a local resonance unit (2). Inside the sound-absorbing frame (1), there is a coiled cavity (12), and the upper and lower sides of the coiled cavity (12) are respectively connected to the inlet pipe (10) and the outlet pipe (11). Inside the coiled cavity (12), an S-shaped channel (16) for sound flow is formed by means of a first partition plate (13) and a second partition plate (14), and the local resonance unit (2) is provided at some turning corners of the S-shaped channel (16). The local resonance unit (2) absorbs the noise propagated in the coiled cavity (12) through cavity resonance; On the inner walls of both sides of the coiled cavity (12), a plurality of partition plates are evenly distributed at equal intervals, namely the first partition plate (13) and the second partition plate (14). The first partition plate (13) and the second partition plate (14) are in an interval offset structure. Between the end of each first partition plate (13) and the second partition plate (14) and the inner wall of the sound-absorbing frame (1), there is a sound transmission channel so that an S-shaped channel (16) for sound wave transmission is formed inside the coiled cavity (12). The two ends of the S-shaped channel (16) are respectively connected to the inlet pipe (10) and the outlet pipe (11); The local resonance unit (2) includes an extension plate (20), a first T-shaped plate (21), a second T-shaped plate (22), and a third T-shaped plate (23). The ends of two adjacent first partition plates (13) and second partition plates (14) are fixedly connected with the extension plate (20). One side of the vertical part of the first T-shaped plate (21) faces the extension plate (20), and there is also a sound transmission channel between them. On the other side of the vertical part of the first T-shaped plate (21), the second T-shaped plate (22) and the third T-shaped plate (23) are respectively provided. There is also a sound transmission channel between the vertical parts of the second T-shaped plate (22) and the third T-shaped plate (23) and the vertical part of the first T-shaped plate (21). The horizontal parts of the first T-shaped plate (21), the second T-shaped plate (22), and the third T-shaped plate (23) are all fixedly connected to the inner wall of the sound-absorbing frame (1). Between the vertical parts of the second T-shaped plate (22) and the third T-shaped plate (23) and the inner wall of the sound-absorbing frame (1), there is a first resonance cavity (24); On one side of the first T-shaped plate (21) facing the second T-shaped plate and the third T-shaped plate (23), a partition plate (26) is horizontally and perpendicularly fixedly connected. The partition plate (26) is fixedly connected to the inner wall of the sound-absorbing frame (1), and the partition plate (26) penetrates through the first resonance cavity (24) to divide the first resonance cavity (24) into upper and lower two cavities, and the lengths of the upper and lower two cavities are different.

2. The broadband noise elimination structure based on a coiled cavity according to claim 1, wherein: On the surfaces of the spaced-apart first partition plates (13), a small hole array (15) is formed, and the small hole array (15) is communicated with the S-shaped channel (16).

3. The broadband noise elimination structure based on a coiled cavity according to claim 2, characterized in that: The cross-sectional area of the coiled cavity (12) is 5 times the cross-sectional area of the inlet pipe (10) and the cross-sectional area of the outlet pipe (11).

4. A broadband noise elimination structure based on a coiled cavity according to claim 1, characterized in that: The sound inlet pipe (10) and the sound outlet pipe (11) are both fixedly mounted on the sound absorption frame (1) in an inserted structure. Fixed plates (25) are respectively fixedly connected to both sides of the sound inlet pipe (10) and the sound outlet pipe (11), and a second resonance cavity (27) is left between the fixed plates (25) and the inner wall of the sound absorption frame (1).

5. A broadband noise elimination structure based on a coiled cavity according to claim 1, characterized in that: The sound inlet pipe (10), the sound outlet pipe (11), the coiled cavity (12), the first partition plate (13), the second partition plate (14), the extension plate (20), the first T-shaped plate (21), the second T-shaped plate (22), and the third T-shaped plate (23) are made of resin, plastic, or hard metal materials, and the S-shaped channel (16), the first resonance cavity (24), and the second resonance cavity (27) are filled with porous sound absorption materials.

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