A broadband noise cancellation device
By designing a multi-layered broadband noise cancellation device, and utilizing multi-stage flow guidance and a double-layer sound absorption structure, the problem of insufficient absorption efficiency of traditional sound-absorbing materials and silencers for low-frequency noise is solved, thus achieving efficient elimination of low-frequency noise.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LIAONING ZHONGKE ENVIRONMENTAL PROTECTION CO LTD
- Filing Date
- 2025-06-11
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies are insufficient to effectively absorb and eliminate broadband low-frequency noise, especially in space-constrained applications. Traditional sound-absorbing materials and silencers are not efficient at absorbing low-frequency noise, resulting in poor noise reduction.
A broadband noise cancellation device with a multi-layer structure includes a sound-absorbing shell, a flow-guiding shell, an air inlet pipe, an air outlet pipe, first and second cavities, and first and second sound-absorbing cotton. Through multi-stage flow guidance and double-layer sound-absorbing structure, it significantly extends the sound wave propagation path, enhances the frictional dissipation of sound energy and sound-absorbing materials, and utilizes microfiber cotton and adjustable units to adapt to different frequency noises.
It significantly improves the absorption efficiency of low-frequency noise, and enhances the noise reduction effect of low-frequency noise through multi-stage flow guidance and double-layer sound absorption structure. It adapts to noise environments of different frequencies and reduces the penetration of low-frequency noise.
Smart Images
Figure CN224417487U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of low-frequency noise cancellation, specifically a broadband noise cancellation device. Background Technology
[0002] Low-frequency noise (typically referring to noise in the 20Hz-250Hz range) is prevalent in industrial environments (such as large fans, compressors, pumps, and duct airflow), building equipment (such as central air conditioning, cooling towers, and elevators), and even transportation due to its long wavelength, strong penetrating power, and slow attenuation. It is difficult to effectively isolate or absorb. Compared to mid- and high-frequency noise, low-frequency noise is more likely to cause discomfort, such as irritability, insomnia, and palpitations, significantly disrupting the work environment and residents' lives.
[0003] Currently, the main technologies used to control low-frequency noise are sound absorption, sound insulation, and silencers. Common sound-absorbing materials (such as porous materials) are effective at absorbing mid-to-high frequency noise, but their absorption efficiency for low-frequency noise is generally low. Often, a large thickness or cavity is required to achieve a certain effect, which limits their effectiveness in space-constrained applications. Traditional silencers (such as resistive, reactive, and impedance composite silencers) can handle noise in specific frequency bands, but they suffer from insufficient sound absorption efficiency when dealing with broadband, especially penetrating, low-frequency noise. Single-layer sound-absorbing structures or sound-absorbing cotton arrangements are insufficient to effectively capture and dissipate low-frequency sound energy, resulting in insufficient low-frequency noise reduction and affecting the overall noise reduction effect. Utility Model Content
[0004] To solve the above problems, namely the problems mentioned in the background art, this utility model proposes a broadband noise cancellation device, comprising:
[0005] Sound-absorbing shell;
[0006] A flow guide shell is fixedly installed inside the sound-absorbing shell;
[0007] An air intake pipe is located inside the air guide shell, and one end of the pipe is fixedly inserted through one side wall of the sound-absorbing shell.
[0008] An exhaust pipe is fixedly installed on one side wall of the sound-absorbing shell and communicates with the sound-absorbing shell;
[0009] The first cavity is formed inside the outer wall of the flow guide shell;
[0010] The first sound-absorbing cotton is disposed inside the first cavity;
[0011] The second cavity is formed inside the outer wall of the sound-absorbing shell;
[0012] The second sound-absorbing cotton is placed inside the second cavity.
[0013] Preferably, two pairs of first annular guide plates are fixedly installed on the inner wall surface of the guide shell and on the outer side of the air intake pipe, and a second annular guide plate is fixedly installed on the outer surface of the air intake pipe and between each pair of first annular guide plates.
[0014] Preferably, an adjustable unit is provided on the inner wall of the air guide shell and on one side of the air intake pipe.
[0015] Preferably, an annular guide plate is fixedly installed on one side of the guide shell and between the inner surface of the sound-absorbing shell and the outer surface of the air intake pipe.
[0016] Preferably, two pairs of connecting rods are fixedly installed on the outer surface of the flow guide shell, and the end of the connecting rod away from the flow guide shell is fixedly connected to the inner surface of the sound-absorbing shell.
[0017] Preferably, both the first sound-absorbing cotton and the second sound-absorbing cotton are microfiber cotton.
[0018] The beneficial technical effects of this utility model are as follows: This device, through the combination of a sound-absorbing shell, a flow-guiding shell, a first cavity and a second cavity, a first annular flow-guiding inclined plate, a second annular flow-guiding inclined plate, an adjustable unit, the curved wall of the flow-guiding shell and the annular flow-guiding plate, as well as the first sound-absorbing cotton and the second sound-absorbing cotton, significantly extends the sound wave propagation path, enhances the interaction and frictional dissipation between sound energy and sound-absorbing materials, and thus effectively solves the problems of strong penetration of low-frequency noise and low absorption efficiency of traditional single-layer structures. Attached Figure Description
[0019] Figure 1 The diagram shows a front sectional view of the present invention.
[0020] Figure 2 The diagram shows a top sectional view of the connecting rod of this utility model.
[0021] The attached figures are labeled as follows: 1. Sound-absorbing shell, 2. Air guide shell, 3. Air inlet pipe, 4. Air outlet pipe, 5. First cavity, 6. First sound-absorbing cotton, 7. Second cavity, 8. Second sound-absorbing cotton, 9. First annular guide plate, 10. Second annular guide plate, 11. Adjustable unit, 12. Annular guide plate, 13. Connecting rod. Detailed Implementation
[0022] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.
[0023] This utility model proposes a broadband noise cancellation device, comprising:
[0024] Sound-absorbing shell 1;
[0025] The airflow guide shell 2 is fixedly installed inside the sound-absorbing shell 1;
[0026] The air intake pipe 3 is located inside the air guide shell 2, and one end is fixed through one side wall of the sound absorption shell 1.
[0027] Several strip-shaped holes are formed on the inner wall surface of the intake pipe 3. When the external airflow enters the intake pipe 3, the strip-shaped holes can reduce the airflow resistance.
[0028] The air outlet pipe 4 is fixedly installed on one side wall of the sound-absorbing shell 1 and is connected to the sound-absorbing shell 1;
[0029] The first cavity 5 is formed inside the outer wall of the flow guide shell 2;
[0030] The first sound-absorbing cotton 6 is disposed inside the first cavity 5;
[0031] The guide shell 2 has a first cavity 5 inside its outer wall, which contains a first sound-absorbing cotton 6 to form the first layer of sound-absorbing structure.
[0032] The second cavity 7 is formed inside the outer wall of the sound-absorbing shell 1;
[0033] The second sound-absorbing cotton 8 is located inside the second cavity 7;
[0034] The sound-absorbing shell 1 serves as the outer shell of the device, forming a noise reduction chamber inside. A second cavity 7 is provided inside its outer wall, with a second sound-absorbing cotton 8 inside, used to absorb the remaining sound energy that penetrates the guide shell 2.
[0035] Specifically, two pairs of first annular guide plates 9 are fixedly installed on the inner wall of the guide shell 2 and on the outer side of the air intake pipe 3, and a second annular guide plate 10 is fixedly installed on the outer surface of the air intake pipe 3 and between each pair of first annular guide plates 9.
[0036] The first annular guide plate 9 forms an acute angle with the inner wall of the guide shell 2, typically between 15 and 45 degrees, with its tilt direction pointing downstream of the airflow. The first annular guide plate 9 is a thin-walled annular structure with an inner diameter larger than the outer diameter of the air inlet pipe 3, forming an annular channel. The second annular guide plate 10 is tilted in a staggered direction with the first annular guide plate 9 and tilts upstream. Its outer diameter is smaller than the inner diameter of the guide shell 2. The first annular guide plate 9 extends from the outside in, and the second annular guide plate 10 extends from the inside out, forming a radially staggered array of reflective surfaces. The channel between the first annular guide plate 9 and the second annular guide plate 10 accelerates the airflow, increasing the relative speed of the sound wave when it comes into contact with the first sound-absorbing cotton 6, thereby enhancing the fiber friction sound energy conversion efficiency.
[0037] Specifically, an adjustable unit 11 is provided on the inner wall of the air guide shell 2 and on one side of the air intake pipe 3;
[0038] The adjustable unit 11 consists of a cylinder and a hemispherical shell. The hemispherical shell is slidably installed inside the guide shell 2 and is in sliding contact with the inner wall of the guide shell 2. The cylinder is fixedly installed on the inner wall of the guide shell 2, and its telescopic end is fixedly connected to the outer surface of the hemispherical shell. It can drive the hemispherical shell to move inside the guide shell 2. The movement of the hemispherical shell can adjust the size of the chamber volume inside the guide shell 2, which can adapt to noise of different frequencies. At the same time, the cylinder is connected to an external air source. Under the action of the air source, the telescopic end of the cylinder can be driven to extend or retract.
[0039] Specifically, an annular guide plate 12 is fixedly installed on one side of the guide shell 2 and between the inner surface of the sound-absorbing shell 1 and the outer surface of the air intake pipe 3.
[0040] Under the action of the annular guide plate 12, the airflow between the guide shell 2 and the air intake pipe 3 can be directed to the space between the guide shell 2 and the sound-absorbing shell 1.
[0041] Specifically, two pairs of connecting rods 13 are fixedly installed on the outer surface of the flow guide shell 2, and the end of the connecting rod 13 away from the flow guide shell 2 is fixedly connected to the inner surface of the sound absorption shell 1.
[0042] The cross-section of the connecting rod 13 is teardrop-shaped, which can reduce airflow resistance and noise generation.
[0043] Specifically, both the first sound-absorbing cotton 6 and the second sound-absorbing cotton 8 are microfiber cotton;
[0044] Microfiber cotton typically has a fiber diameter of less than 1 micrometer. This extremely fine fiber structure causes sound waves to be continuously rubbed and absorbed as they pass through, thus achieving a good sound absorption effect. In addition, the disordered stacking of microfiber cotton fibers also enhances its sound absorption capacity, and the increase in density and thickness can further improve the sound absorption effect.
[0045] Working Principle: Low-frequency noise, accompanied by airflow, enters the device through the inlet pipe 3. The noise sound waves propagate in the airflow medium and diffuse within the device along the airflow path. The adjustable unit 11 inside the guide shell 2 can adjust the size of the chamber within the guide shell 2 to accommodate noise of different frequencies. The first annular guide ramp 9 and the second annular guide ramp 10 are arranged alternately to form a multi-level oblique reflection surface. Under the action of the first annular guide ramp 9 and the second annular guide ramp 10, the sound waves repeatedly collide and reflect, significantly extending the propagation path and increasing the sound path. At the same time, it guides the airflow to flow smoothly to reduce turbulent regenerated noise. The annular guide plate 12 further guides the sound waves into the sound absorption. The cavity between shell 1 and guide shell 2 prevents sound energy from escaping directly. Sound waves pass through the first cavity 5 on the outer wall of guide shell 2, where the first sound-absorbing cotton 6 converts sound energy into heat energy through fiber friction. The remaining sound waves continue to penetrate to the second cavity 7 on the outer wall of sound-absorbing shell 1, where they are absorbed a second time by the second sound-absorbing cotton 8. The double-layer sound-absorbing structure significantly improves the capture efficiency of low-frequency sound energy through the superposition effect. The multi-stage guide structure causes sound waves to reflect multiple times in a limited space, and some of the reverse sound waves interfere with and cancel out the original sound waves, further weakening the low-frequency sound pressure. The airflow that has undergone noise reduction treatment is discharged through the air outlet 4. At this time, the low-frequency noise energy carried by the airflow has been greatly reduced through sound absorption dissipation and interference.
[0046] Although the present invention has been described with reference to preferred embodiments, various modifications can be made to it and components can be replaced with equivalents without departing from the scope of the present invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
[0047] In the description of this utility model, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0048] Furthermore, it should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0049] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to those processes, articles, or apparatus / devices.
[0050] The technical solution of this utility model has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is obviously not limited to these specific embodiments. Without departing from the principle of this utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this utility model.
Claims
1. A broadband noise cancellation device, characterized in that, include; Sound-absorbing shell (1); The flow guide shell (2) is fixedly installed inside the sound-absorbing shell (1); An air intake pipe (3) is located inside the air guide shell (2), and one end of it is fixed through one side wall of the sound-absorbing shell (1). An air outlet pipe (4) is fixedly installed on one side wall of the sound-absorbing shell (1) and communicates with the sound-absorbing shell (1); The first cavity (5) is formed inside the outer wall of the flow guide shell (2); The first sound-absorbing cotton (6) is disposed inside the first cavity (5); The second cavity (7) is formed inside the outer wall of the sound-absorbing shell (1); The second sound-absorbing cotton (8) is placed inside the second cavity (7).
2. The broadband noise cancellation device according to claim 1, characterized in that, Two pairs of first annular guide plates (9) are fixedly installed on the inner wall of the guide shell (2) and on the outer side of the air intake pipe (3). A second annular guide plate (10) is fixedly installed on the outer surface of the air intake pipe (3) and between each pair of first annular guide plates (9).
3. The broadband noise cancellation device according to claim 1, characterized in that, An adjustable unit (11) is provided on the inner wall of the air guide shell (2) and on one side of the air intake pipe (3).
4. The broadband noise cancellation device according to claim 1, characterized in that, An annular guide plate (12) is fixedly installed on one side of the guide shell (2) and between the inner surface of the sound-absorbing shell (1) and the outer surface of the air intake pipe (3).
5. A broadband noise cancellation device according to claim 1, characterized in that, Two pairs of connecting rods (13) are fixedly installed on the outer surface of the flow guide shell (2), and the end of the connecting rod (13) away from the flow guide shell (2) is fixedly connected to the inner surface of the sound absorption shell (1).
6. A broadband noise cancellation device according to claim 1, characterized in that, Both the first sound-absorbing cotton (6) and the second sound-absorbing cotton (8) are microfiber cotton.