Superlattice sheet resistive muffler

Abstract

The present application relates to a kind of super-structure sheet resistive muffler, it includes outer frame and the multiple muffling sheets of inserting in the outer frame, the outer frame both ends have opening and muffling sheet extends between both ends opening, the muffling sheet includes super-structure sound-absorbing material layer, air layer outside super-structure sound-absorbing material layer both sides, sound-absorbing cotton layer is arranged outside the air layer and the facing structure of sound-absorbing cotton layer outside, the super-structure sound-absorbing material layer includes two layers of super-structure sound-absorbing plate arranged back to back, small hole is arranged on the outer side of the super-structure sound-absorbing plate, the small hole is directed to the air layer, the muffling sheet further includes bolt, the bolt is sequentially passed through the sound-absorbing cotton layer and the air layer and is screwed on the super-structure sound-absorbing plate, and the bolt outer periphery between the sound-absorbing cotton layer and the super-structure sound-absorbing plate is equipped with compression spring. High frequency and low frequency noise have good removal ability.

Description

TECHNICAL FIELD

[0001] The present application relates to a super-structure sheet resistive muffler. BACKGROUND

[0002] Muffler Silence is a device that prevents sound propagation while allowing airflow, and is an important measure to eliminate aerodynamic noise. Generally, mufflers are installed on the airflow path of aerodynamic equipment (such as air blowers, air compressors) or in the intake and exhaust systems to reduce noise. It is widely used in power generation, chemical industry, metallurgy, textile and other industrial plants for various types of boilers, steam turbine / pipeline exhaust, fans, ventilation ducts, exhaust systems of internal combustion engines, safety doors and other equipment.

[0003] Mufflers are simple in structure and low in maintenance cost, and have become one of the main means of industrial noise control. On the one hand, industrial noise control not only puts forward higher demands on the noise reduction performance of mufflers, but also puts forward higher requirements on their structure, materials and design theory. Mufflers are usually divided into resistive mufflers, reactive mufflers, impedance composite mufflers, micro-perforated plate mufflers, small hole mufflers and active mufflers according to different noise reduction principles. Among them, the noise (absorption) materials used in resistive mufflers are traditional porous materials, which cannot achieve low-frequency noise reduction in a limited length due to the limitation of the intrinsic state of air in the flow phase on the internal visco-thermal properties. The reactive muffler still follows the variable cross-section design theory to achieve effective low-frequency noise reduction, but its volume is large and the cost is high.

[0004] In recent years, acoustic metamaterials and their design theory are emerging, and they have strong control ability over low-frequency sound waves. In view of this, it is of great significance to introduce acoustic metamaterials and their design theory into mufflers for industrial noise control, especially for low-frequency noise elimination. Chinese patent document "CN216590546U" discloses a super-structure muffler, which makes a preliminary attempt to introduce super-structure materials into mufflers.

[0005] In summary, there are still many deficiencies in the muffler products on the market at present, which are specifically manifested in the following aspects:

[0006] 1. Low-frequency noise reduction is insufficient;

[0007] 2. In the case of a certain space, when the noise reduction amount index is met, the flow resistance rate of the muffler is too high, and the pressure loss is large;

[0008] 3. In the case of a certain noise reduction amount, reducing the flow resistance rate and reducing the pressure loss makes the muffler too large in size and expensive in cost;

[0009] 4. The frequency spectrum characteristics of the muffler are difficult to customize. SUMMARY

[0010] The present application aims at providing a super-structure sheet type resistive muffler, which can effectively eliminate high and low frequency sound.

[0011] To achieve the above-mentioned purpose, the present application adopts the technical scheme of:

[0012] The present application provides a super-structure sheet type resistive muffler, which comprises an outer frame and a plurality of muffling sheets inserted into the outer frame, the outer frame has openings at both ends and the muffling sheets extend between the openings at both ends, the muffling sheet comprises a super-structure sound-absorbing material layer, air layers outside the super-structure sound-absorbing material layer, a sound-absorbing cotton layer arranged outside the air layers, and a protective structure arranged outside the sound-absorbing cotton layer, the super-structure sound-absorbing material layer comprises two layers of super-structure sound-absorbing plates arranged back to back, the super-structure sound-absorbing plates are provided with small holes on the outer sides, the small holes point to the air layers, the muffling sheet further comprises bolts, the bolts pass through the sound-absorbing cotton layer and the air layers in sequence and are screwed on the super-structure sound-absorbing plates, and a compression spring is sleeved on the outer periphery of the bolt between the sound-absorbing cotton layer and the super-structure sound-absorbing plate.

[0013] In this design, the muffler adopts the form of sheet type resistive muffler, which reduces the flow resistance and pressure loss of the muffler to a certain extent.

[0014] Preferably, the depth of the bolt into the super-structure sound-absorbing plate is adjustable.

[0015] Preferably, the protective structure is one of a perforated plate, glass cloth and wire mesh.

[0016] Preferably, the bolts are distributed at the corner positions of the muffling sheet.

[0017] Preferably, the outer surface of the outer frame is provided with sound-absorbing cotton or other resistive sound-absorbing materials.

[0018] Preferably, the material of the super-structure sound-absorbing plate is resonant sound-absorbing material, which is selected and customized according to the low frequency sound-absorbing requirement of the muffler.

[0019] Thanks to the above technical scheme, the present application has the following advantages compared with the prior art:

[0020] The super-structure sheet type resistive muffler of the present application comprises an outer frame and a muffling sheet arranged in the outer frame, and the muffling sheet comprises a super-structure sound-absorbing material layer, an air layer outside the super-structure sound-absorbing material layer, a sound-absorbing cotton layer arranged outside the air layer, and a protective structure arranged outside the sound-absorbing cotton layer, so that the noise of high frequency components can be eliminated by the sound-absorbing cotton layer, and the low frequency noise elimination capability of the muffler can be improved by the super-structure sound-absorbing material layer, and the super-structure sound-absorbing material can absorb low frequency noise without a large structure due to its excellent sub-wavelength sound-absorbing capability, thereby reducing the overall structure size of the muffler and reducing the production cost, and the muffler has good removal capability for high frequency and low frequency noise. BRIEF DESCRIPTION OF DRAWINGS

[0021] Some specific embodiments of the present application will be described in detail below with reference to the accompanying drawings, which are exemplary but not limiting. The same reference signs in the drawings indicate the same or similar components or parts. Those skilled in the art should understand that the drawings are not necessarily drawn to scale. In the drawings:

[0022] Figure 1 is a cross-sectional view of the super-structure sheet type resistive muffler of the preferred embodiment of the present application;

[0023] Figure 2 is a cross-sectional view of the muffling sheet in Figure 1

[0024] Figure 3 is a front view of the muffling sheet in Figure 2

[0025] In the drawings, the reference signs are explained as follows:

[0026] 1, outer frame; 11, opening; 12, sound-absorbing cotton;

[0027] 2, muffling sheet; 21, super-structure sound-absorbing material layer; 211, super-structure sound-absorbing plate; 2111, small hole; 22, air layer; 23, sound-absorbing cotton layer; 24, protective structure; 241, hollow; 25, bolt; 251, knob; 26, compression spring;

[0028] 3, air duct. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings, and obviously, the described embodiments are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] ​​In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] like Figure 1 The cross-sectional view of the superstructure resistive muffler shown includes an outer frame 1 and multiple muffler plates 2 inserted within the outer frame 1. The outer frame 1 is tubular, with openings 11 at both ends. Because... Figure 1 The line of sight in the diagram extends along the outer frame 1, so the two openings 11 appear to overlap. The interior of the outer frame 1 contains the air duct 3 for exhaust ventilation. The vibration waves generated by the exhaust are transmitted to the outside of the outer frame 1, producing noise. Noise is absorbed by the sound-absorbing sheet 2 inside the outer frame 1.

[0033] The sound-absorbing plate 2 has multiple pieces, extending along the extension direction of the outer frame 1, that is, extending between the two end openings 11. The cross-sectional view of the sound-absorbing plate 2 is shown below. Figure 2 As shown, the sound-absorbing sheet 2 includes a metamaterial layer 21, air layers 22 on both sides of the metamaterial layer 21, a sound-absorbing cotton layer 23 disposed on the outside of the air layers 22, and a protective structure 24 disposed on the outside of the sound-absorbing cotton layer 23. The metamaterial layer 21 comprises two back-to-back metamaterial sound-absorbing panels 211, which are integrally formed or bonded together with an adhesive. Multiple small holes 2111 are provided on the outer surface of the metamaterial sound-absorbing panels 211, pointing towards the air layers 22. The small holes 2111 include resonance holes, such as Helmholtz resonance holes. The sound-absorbing cotton layer 23 is fixed to the metamaterial sound-absorbing panel 211 by bolts 25. The bolts 25 pass through the sound-absorbing cotton layer 23 and the air layers 22 sequentially and are screwed onto the metamaterial sound-absorbing panel 211. A compression spring 26 is fitted around the outer periphery of the bolt 25 between the sound-absorbing cotton layer 23 and the ultra-thin sound-absorbing plate 211. When the compression spring 26 is compressed, its tension holds the sound-absorbing cotton layer 23 tightly against the facing structure 24. The depth to which the bolt 25 is screwed into the ultra-thin sound-absorbing plate 211 is adjustable, thereby adjusting the thickness of the air layer 22 and consequently the silencer's silencing frequency, thus allowing for customization of the silencer's spectral characteristics. A knob 251 is located at the outer end of the bolt 25, allowing adjustment by turning the bolt 25. Figure 3, bolts 25 are distributed in four corner positions of the sound-absorbing sheet 2. As shown in Figure 3 The fender structure 24 is provided with a plurality of hollows 241. The fender structure 24 can be one of a perforated plate, a glass cloth and a wire mesh, which is selected by the gas flow rate in the air duct 3.

[0034] The sound-absorbing cotton layer 23 is mainly used for eliminating high-frequency noise, the super-structured sound-absorbing material layer 21 is mainly used for eliminating low-frequency noise, and the air layer 22 is beneficial to impedance matching. The thickness of the air layer 22 can be adjusted, so that the frequency spectrum characteristics of the sound absorber can be customized.

[0035] In this example, the outer frame 1 is also provided with a sound-absorbing cotton 12 on the outer surface, so as to absorb the high-frequency noise diffused from the air duct 3.

[0036] The beneficial effects of the example are:

[0037] (1) The sound-absorbing cotton layer 23 is used to eliminate high-frequency noise, and the super-structured sound-absorbing plate 211 is used to eliminate low-frequency noise, so that high-frequency and low-frequency noise can be eliminated;

[0038] (2) The thickness of the air layer 22 is adjusted by the bolts 25, so as to adjust the sound-absorbing frequency of the sound absorber, so that the frequency spectrum characteristics of the sound absorber can be customized.

[0039] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A metasurface sheet resistive silencer, characterized by, It includes an outer frame (1) and a plurality of sound-absorbing sheets (2) inserted in the outer frame (1), the outer frame (1) has openings (11) at both ends and the sound-absorbing sheets (2) extend between the openings (11) at both ends, the sound-absorbing sheet (2) includes a metamaterial sound-absorbing material layer (21), an air layer (22) outside the metamaterial sound-absorbing material layer (21), a sound-absorbing cotton layer (23) arranged outside the air layer (22), and a facing structure (24) arranged outside the sound-absorbing cotton layer (23), the metamaterial sound-absorbing material layer (21) includes two layers of metamaterial sound-absorbing plates (211) arranged back to back, the metamaterial sound-absorbing material layer (21) is used for eliminating low-frequency noise, the metamaterial sound-absorbing plate (211) is provided with a small hole (2111) on the outer side, the small hole (2111) points to the air layer (22), the sound-absorbing sheet (2) further includes a bolt (25), the bolt (25) passes through the sound-absorbing cotton layer (23) and the air layer (22) in sequence and is screwed on the metamaterial sound-absorbing plate (211), a compression spring (26) is sleeved outside the periphery of the bolt (25) between the sound-absorbing cotton layer (23) and the metamaterial sound-absorbing plate (211), and the depth of the bolt (25) into the metamaterial sound-absorbing plate (211) is adjustable.

2. The metamaterial sheet resistive silencer of claim 1, wherein: The facing structure (24) is one of a perforated plate, glass cloth and iron wire mesh.

3. The metamaterial sheet resistive silencer of claim 1, wherein: The bolt (25) is distributed at the corner position of the sound-absorbing sheet (2).

4. The metamaterial sheet resistive silencer of claim 1, wherein: The outer surface of the outer frame (1) is provided with sound-absorbing cotton (12) or other resistive sound-absorbing material.

5. The metamaterial sheet resistive silencer of claim 1, wherein: The material of the metamaterial sound-absorbing plate (211) is a resonant sound-absorbing material, which is selected and customized according to the low-frequency sound-absorbing requirements of the sound absorber.

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