CN211016506U - A beam cavity resonance composite structure muffler - Google Patents

Abstract

The utility model develops a beam cavity resonance composite structure muffler on the basis of the research on the original tube bundle perforated plate composite resonance sound absorption structure. The sound absorption advantage of the environmental protection sound-absorbing cotton overcomes the defect of the resonance sound absorption of the tube-bundle perforated plate resonance sound-absorbing device, and the sound-absorbing effect is good. Very good effect.

Description

A beam cavity resonance composite structure muffler

technical field

The utility model relates to the technical field of noise control and acoustic materials, in particular to a beam cavity resonance composite structure muffler.

Background technique

As human beings enter the 21st century, industrial enterprises, aviation, railways, urban environment, road traffic, building construction, and communities have very prominent demands for low-frequency noise reduction. Low-frequency noise control in limited space has become the current technology in the field of international noise control. bottleneck. Therefore, it is urgent to research and develop new sound-absorbing structures with high-efficiency low-frequency and wide-band sound absorption characteristics in a limited space and with green environmental protection advantages. To this end, the Institute of Acoustics, Chinese Academy of Sciences has carried out research on the mechanism and application of low-frequency broadband sound-absorbing structures in limited space. For the first time in the world, a new type of resonance sound-absorbing structure, that is, a flexible tube-bundle perforated plate resonance sound-absorbing structure, was proposed, and the structure and its derivative structures were designed as a kind of muffler, which was successfully applied to some key industrial and environmental noise control projects.

The tube-bundle type perforated plate resonance sound absorption device is essentially a resonance sound absorption, so it is inevitable that there will be "big ups and downs" in the sound absorption characteristics. There are both sound absorption peaks and sound absorption valleys. On the basis of the invention patent of "tube bundle type perforated plate resonance sound absorption device", the research group of the Institute of Acoustics of the Chinese Academy of Sciences combined it with the micro-slit perforated plate sound absorption structure and sound absorption cotton to form a "beam cavity resonance sound absorption structure". The structural achievement has won the national invention patent "a composite resonance sound absorption structure of tube bundle perforated plate" (invention patent number: 200910119946.9). The beam cavity resonance sound absorption structure integrates the sound absorption advantages of the tube bundle perforated plate sound absorption structure, the micro-slit perforated plate sound absorption structure and the organic environmental protection sound absorption cotton, and overcomes the resonance sound absorption of the tube bundle perforated plate resonance sound absorption device” Big ups and downs" defect, with excellent acoustic characteristics. In general, the beam cavity resonance sound absorption structure has the following advantages: excellent low frequency sound absorption performance, "low frequency direction frequency shift" characteristics; large sound resistance, sound absorption frequency bandwidth, "lumen coupling resonance enhanced sound absorption" characteristics; The cavity depth is significantly reduced, and high sound absorption performance can be maintained; the length and structure of the flexible pipe can be adjusted, and the resonance sound absorption frequency band and sound absorption coefficient can be actively tuned.

However, when the environmental condition that needs to be muffled is the type of pipe, there are often special requirements such as ensuring the ventilation state of the original pipe, and special requirements are put forward for the size, shape and structure of the muffler. Since the original invention did not consider these Special application and structural requirements challenge its use in this application. In addition, the performance requirement measured by the sound absorption coefficient measured by the national standard standing wave tube and the reverberation chamber adopted by the original invention is also inconvenient to be used in such an environment.

Utility model content

Aiming at the deficiencies of the prior art, the utility model provides a beam cavity resonance composite structure muffler. The beam cavity resonance sound absorption structure integrates the sound absorption advantages of the tube bundle perforated plate sound absorption structure, the micro-slit perforated plate sound absorption structure and the organic environmental protection sound absorption cotton, and overcomes the resonance sound absorption of the tube bundle perforated plate resonance sound absorption device” Big ups and downs" defect, with excellent acoustic characteristics. At the same time, the shape structure and internal structure are designed to suit the noise reduction requirements of the pipeline environment, which can meet the requirements of ventilation capacity while reducing noise under the pipeline conditions.

The technical solution adopted by the present invention to solve the above technical problems is a muffler,

include:

a closed cavity composed of an inner wall and an outer shell, the inner wall is in the shape of a pipe, and there are a plurality of holes facing the cavity;

a connecting pipe interface that communicates with the pipe-shaped space surrounded by the inner wall and extends outward from the two outlets;

The tube-shaped inner wall also includes a tube bundle, the tube bundle is arranged by N tubes, the tubes are placed in the closed cavity, and an open end of each tube is inserted into the perforated plate. The hole or the transition joint is used to insert the pipe into the perforated plate hole and the cylindrical pipe-shaped perforated plate is connected, and the other end is an open end or a closed end;

the diameter of the pipe is equal to the diameter of the hole;

The N is equal to or smaller than the number of holes.

Preferably, the inner wall of the muffler is cylindrical; the shape of the outer shell is cylindrical, including curved cylindrical, or other deformations.

Preferably, in the muffler, the pipe diameter of the inner wall is larger than the pipe diameter of the connecting pipe, and a layer of environmental protection sound-absorbing material is laid on one side of the pipe with the short inner wall diameter.

Preferably, the inner and outer diameters and lengths of the muffler are designed with different sizes according to different requirements.

Specifically, the demand conditions include noise frequency, required amount of noise reduction, and the like.

Preferably, the pipe-shaped perforated plate on the inner wall of the muffler is a steel plate, a copper plate, a stainless steel plate, an aluminum plate, a plastic plate, a PVC plate, a PE plate or a wooden plate.

Preferably, in the muffler, the inner wall further includes micro slits.

Specifically, the width of the micro-slit is 0.01-4 mm, the length is 1-200 mm, and the penetration rate ρ is 0.1%-30%.

Preferably, the arrangement of the holes and the micro-slits on the pipe-shaped perforated plate on the inner wall of the muffler is consistent or inconsistent, and the holes and the micro-slits are arranged independently.

Preferably, the thickness of the inner wall plate of the muffler is 0.5-10 mm, the hole diameter is 0.1-5 mm, and the perforation rate σ of the hole is 0.1%-30%.

Preferably, the cavity depth of the closed cavity of the muffler is 10-1500 mm.

Preferably, in the muffler, the pipe is a metal pipe, a ceramic pipe, a rubber pipe or a plastic pipe; the length of the pipe is less than the cavity depth of the closed cavity, or greater than the cavity depth of the closed cavity.

Preferably, in the muffler, the porous sound-absorbing material layer laid on the pipe side of the inner wall of the pipe-shaped perforated plate is glass wool, rock wool, mineral wool, petroleum cracked environmentally friendly sound-absorbing cotton or foamed aluminum, and the porous sound-absorbing material layer is The thickness of the sound-absorbing material layer is 10 to 300 mm.

Preferably, the main body part of the muffler is cylindrical and passes through a pipe in the middle.

Preferably, the main body part of the muffler also includes curved, other deformed cylindrical shapes and other shapes, and a pipe is passed in the middle.

Compared with the prior art, the technical solution adopted by the present utility model has the following technical advantages:

1) Has excellent acoustic properties. Including: excellent low-frequency sound absorption performance, "low frequency direction frequency shift" characteristics; large sound resistance, sound absorption frequency bandwidth, "lumen coupling resonance enhanced sound absorption" characteristics; can significantly reduce the cavity depth, and can maintain a high The sound absorption performance of the flexible pipe can be adjusted; the length and structure of the flexible pipe can be adjusted, and the resonance sound absorption frequency band and sound absorption coefficient can be actively tuned.

2) It is suitable for special scene requirements and structural requirements to reduce noise under pipeline conditions. The muffler equipment in this scenario has special special requirements, mainly the requirements of ventilation capacity, that is, the reduction of the wind speed through the muffler cannot exceed a certain limit, and the restrictions on the shape, size and structure of the muffler brought by the pipeline. The original invention does not consider these conditions and restrictions, and cannot be directly applied to this situation. The design structure of the utility model overcomes these limitations, and can well meet the user's noise reduction requirements under pipeline conditions.

3) The performance requirements of the utility model are changed from the sound absorption coefficient measured by the national standard standing wave tube and the reverberation chamber, which is based on the muffler length, inner diameter, etc. as the structure parameters. reduce the number of decibels) as a performance evaluation standard. Such changes make it easier for the user to measure the performance of the muffler under pipe conditions.

Description of drawings

By describing the embodiments of the present specification in conjunction with the accompanying drawings, the embodiments of the present specification can be made clearer:

1 is a cross-sectional view of a beam cavity resonance composite structure muffler provided by the present utility model

Fig. 2 is the sectional view of the beam cavity resonance composite structure muffler provided by the utility model with environmental protection sound-absorbing cotton

3 is a side plan view of the beam cavity resonance composite structure muffler provided by the present invention

Fig. 4 is the appearance diagram of the beam cavity resonance composite structure muffler provided by the utility model

Fig. 5 is the noise spectrum comparison of the 1/3 octave band of the measuring point about 100 meters away from the Jiqinyu 3212 demonstration ship before and after the noise control of an example cavity muffler with a cavity depth of 150mm provided by the present utility model

Fig. 6 is the noise spectrum comparison of the 1/3 octave noise spectrum of an example cavity muffler with a cavity depth of 100mm provided by the present utility model, which is about 100 meters away from the Jiqinyu 3212 demonstration ship before and after noise control

Detailed ways

The embodiments of the technical solutions of the present utility model will be described in detail below with reference to the accompanying drawings.

It should be noted that, unless otherwise specified, the technical or scientific terms used in the present application shall have the usual meanings understood by those skilled in the art to which the present invention belongs.

Fig. 1, Fig. 2 are beam cavity resonance composite structure muffler example sectional views provided by the present utility model, respectively are without and with the example diagram of environmental protection sound-absorbing cotton, and the concrete structure of muffler is as follows:

A closed cavity composed of the inner wall of the muffler with the beam cavity resonance composite structure and the muffler shell (component 2 in Fig. 1 and Fig. 2 ), this cavity is the main part of the muffler function, in one embodiment , the closed cavity shell is cylindrical.

The inner wall of the muffler is a cylindrical pipe-shaped perforated plate (component 4 in Figure 1 and Figure 2), and the cylindrical pipe-shaped inner wall is formed by the perforated plate. Pass through the middle, that is, the need for ventilation.

The cylindrical connecting pipes extending outward from both ends of the inner wall of the cylindrical muffler (as shown in component 1 in Fig. 1 and Fig. 2 ) are used to connect the connecting pipes with pipes that need to be muffled. The specific connection method is to cut a section from the middle of the pipeline that needs to be muffled, install the cylindrical muffler at the cut-off part, and connect the connecting pipes at both ends of the muffler to the two outlets exposed in the middle of the pipe that needs to be muffled. In this way, the muffler is actually combined with the pipe that needs to be muffled into a pipe.

In one embodiment, the diameter of the inner wall of the muffler is the same as the diameter of the connecting pipe. See Figure 1 and Figure 3.

In one embodiment, the pipe diameter of the inner wall of the muffler is inconsistent with the pipe diameter of the connecting pipe, and the pipe diameter of the inner wall is larger than the pipe diameter of the connecting pipe. In this case, use the extra pipe diameter space to lay a layer of porous pipes on the inner wall of the muffler. Environmentally friendly sound absorbing material layer (component 5 in Figure 2). The porous environment-friendly sound-absorbing material layer may be composed of glass wool, rock wool, mineral wool, petroleum-cracked environment-friendly sound-absorbing cotton or foamed aluminum, and the thickness of the porous environment-friendly sound-absorbing material layer is 10-300 mm. See Figure 2.

The inner wall of the muffler, that is, the cylindrical pipe-shaped perforated plate, is pierced with micro-slits and holes. The micro-slots and holes are used to provide two kinds of sound-absorbing structures, the micro-slit sound absorption structure and the tube bundle type perforated plate resonance sound absorption structure. It needs to work in conjunction with the tube bundle described later.

The cylindrical pipe-shaped perforated plate also includes a tube bundle (component 3 in FIG. 1 and FIG. 2 ), the tube bundle is arranged by N tubes, and the tubes are placed in the closed cavity. and one open end of each pipe is inserted into the perforated plate or the pipe is inserted into the perforated plate and connected with the cylindrical pipe-shaped perforated plate with a transition joint, and the other end is an open end or a closed end.

The tube bundle can be but not necessarily a curved flexible tube bundle. If it is a flexible tube bundle, its length is not limited by the depth of the cavity of the perforated plate resonant sound absorbing structure (the length can be designed to vary in length to tune the resonant frequency and change the The sound absorption coefficient can achieve the purpose of modulating and broadening the sound absorption frequency band), and the length of each tube can be smaller than the cavity depth or larger than the cavity depth. The function of the tube bundle is that since the slender tubes are arranged in the closed cavity and embedded in the perforated plate, the modulation characteristics of the tube length and the tube bundle structure on the resonance absorption peak and the sound absorption frequency band (increase the sound resistance, strengthen the sound absorption; increase the sound quality, promote the The resonance absorption peak shifts to low frequency; modulation broadens the sound absorption band) not only helps to avoid the trough of the sound absorption of the micro-slit sound-absorbing structure, but also its sound-absorbing frequency band is wider than that of the traditional perforated plate resonance sound-absorbing structure and the micro-slit sound-absorbing structure , so as to increase the sound absorption coefficient, enhance the effective absorption of medium and low frequency noise, improve the high frequency sound absorption effect, and broaden the sound absorption frequency band; that is, on the one hand, the sound resistance of the perforated plate resonance sound absorption structure is greatly increased, and on the other hand, due to The increase of sound quality makes the resonance frequency move to low frequency, meanwhile, the tube resonance of the slender tube bundle and the cavity resonance of the perforated plate resonance sound absorption structure are coupled with each other, thus broadening the effective sound absorption frequency band.

The diameter of the tube is equal to the diameter of the hole.

The width of the micro-slits on the perforated plate is 0.01-4 mm, the length is 1-200 mm, and the penetration rate ρ is 0.1%-30%, where the penetration rate is: the total area of all micro-slits/perforated plate area, It should be noted that the upper limit should not only calculate the area of micro-slits, but also the area of holes, that is, the sum of the areas of micro-slits and holes divided by the area of the perforated plate cannot exceed the upper limit.

The number N of tubes in the tube bundle is equal to or less than the number of holes.

In different embodiments, the inner diameter, outer diameter and length of the beam cavity resonance composite structure muffler can be designed with different dimensions according to different implementations or different requirements. The considered requirements are in different embodiments. , including the noise frequency, the required amount of noise reduction, etc.

In different embodiments, the material of the cylindrical pipe-shaped perforated plate of the beam cavity resonance composite structure muffler can be steel plate, copper plate, stainless steel plate, aluminum plate, plastic plate, PVC plate, PE plate or wood board.

In different embodiments, the arrangement of holes and micro-slits on the cylindrical pipe-shaped perforated plate of the beam cavity resonance composite structure muffler is consistent or inconsistent, and the holes and the micro-slits are arranged independently.

In different embodiments, the thickness of the cylindrical pipe-shaped perforated plate of the beam cavity resonance composite structure muffler is 0.5-10 mm, the diameter of the hole is 0.1-5 mm, and the perforation rate σ of the hole is 0.1%-30%, here The perforation rate is: the total area of all holes/perforated plate area. It should be noted that the upper limit should not only calculate the hole area, but also calculate the micro-slit area, that is, the sum of the area of the micro-slit and the hole divided by the area of the perforated plate cannot exceed this limit. Maximum upper limit value.

In different embodiments, the cavity depth variation range of the closed cavity of the beam cavity resonance composite structure muffler is 10-1500 mm.

In different embodiments, the tubes in the bundle cavity resonance composite structure muffler tube bundle may be metal tubes, ceramic tubes, rubber tubes or plastic tubes; the length of the tube is less than the depth of the closed cavity, or greater than the The closed cavity cavity is deep.

In one embodiment, the main body part of the beam cavity resonance composite structure muffler is cylindrical with a pipe in the middle, that is, the shell part of the closed cavity is cylindrical with both upper and lower sides open in the middle.

In one embodiment, the main part of the beam cavity resonance composite structure muffler is in the shape of a curved cylinder with a pipe passing through the middle. This kind of deformation is mainly determined according to the needs of the installation environment and the performance requirements to be achieved.

Field tests of several embodiments of the present invention and their combinations

The Institute of Acoustics of the Chinese Academy of Sciences has designed a total of 5 diesel engine beam cavity resonance exhaust mufflers of 3 different specifications (that is, the 3 embodiments of the present utility model), which are respectively 2 beams with cavity depth of 100mm*length of 500mm and cavity depth of 150mm*length of 500mm. Cavity resonance exhaust muffler and 1 elbow-type beam cavity resonance exhaust muffler with a cavity depth of 150mm. Afterwards, the Institute of Acoustics and the processing manufacturer jointly conducted on-site installation and acoustic optimization comparison tests for noise control of fishing boats on the Jiqinyu 3212 demonstration boat using the embodiment in Beidaihe.

The following are the actual measured data of each embodiment in the test, on the diesel engine exhaust muffler:

1) Two beam cavity mufflers with a length of 500mm and a cavity depth of 150mm are combined with the noise reduction effect of the cavity muffler elbow. The noise at the 100-meter measuring point reaches the environmental background noise of 49.9dBA, and the noise reduction is 12.9dBA, that is, the sound energy Attenuated by 94.9%. Even the low-frequency noise reduction in the range of 20-250Hz has reached 13-25dB, that is, the sound energy is attenuated by 95%-99.7%;

2) Two beam cavity mufflers with a length of 500mm and a cavity depth of 150mm have a sound attenuation of 11.6dBA, that is, the sound energy is attenuated by 93.1%;

3) A beam cavity muffler with a length of 500mm and a cavity depth of 150mm plus a cavity muffler elbow, the noise reduction is 10.2dBA;

4) The muffler of a beam cavity muffler with a length of 500mm and a cavity depth of 150mm is 9.2dBA, that is, the sound energy is attenuated by 88.0%;

5) 2 sections of 500mm long, cavity depth of 100mm, the muffler of the beam cavity muffler is 10.5dBA, that is, the sound energy is attenuated by 91.1%;

6) 1 section of 500mm long, cavity depth of 100mm, the muffler of the beam cavity muffler is 8.5dBA, that is, the sound energy is attenuated by 85.9%.

It can be seen from the above experimental data and the comparison chart of noise reduction effect (Figure 5, Figure 6) that in the combination of each embodiment used in this test, a cavity muffler with a cavity depth of 150mm plus a cavity muffler bend is used. The combination of the head, the noise reduction effect is the best.

It can be seen from the above embodiments that the present invention discloses a beam cavity resonance composite structure muffler. Has excellent acoustic properties. Including: excellent low-frequency sound absorption performance, "low frequency direction frequency shift" characteristics; large sound resistance, sound absorption frequency bandwidth, "lumen coupling resonance enhanced sound absorption" characteristics; can significantly reduce the cavity depth, and can maintain a high It can adjust the length and structure of the flexible pipe, and actively tune the resonance sound absorption frequency band and sound absorption coefficient; it can well meet the needs of reducing noise under pipeline conditions, and has special restrictions on noise reduction under pipeline conditions. , such as requirements for ventilation capacity, constraints on muffler shape, size, structure and performance requirements, give solutions and achieve excellent muffler effect.

Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, as for the system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and for related parts, please refer to the partial descriptions of the method embodiments.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention The protection scope of the utility model, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims (10)

1. A muffler, characterized in that the muffler comprises:

the inner wall surrounds a pipeline-shaped space;

a housing; the shell and the inner wall enclose a closed cavity;

the connector is in a pipeline shape, is communicated with the pipeline-shaped space surrounded by the inner wall and extends outwards from outlets at two ends of the connector;

the inner wall also comprises a plurality of holes facing the closed cavity;

the inner wall also comprises a tube bundle, the tube bundle is formed by arranging N tubes, the tubes are arranged in the closed cavity, one open end of each tube is inserted into the inner wall hole or the tube is inserted into the inner wall hole by a transition joint to be connected with the inner wall, and the other end of each tube is an open end or a closed end;

the diameter of the pipe is equal to that of the hole;

the N is equal to or less than the number of the holes;

the inner wall also comprises micro-slits.

2. The muffler of claim 1 wherein the inner wall is cylindrical pipe-shaped; the shape of the housing may be cylindrical, including curved cylinders, or other variations.

3. The muffler according to claim 1, wherein the inner wall has a diameter larger than that of the connecting pipe, and a layer of sound-absorbing material is laid on the side of the pipe having a short inner wall diameter.

4. The muffler of claim 1, wherein the inner and outer diameters and the length of the muffler are designed in different sizes according to different requirements.

5. The muffler of claim 4, wherein the demand conditions include a noise frequency, a required amount of sound suppression.

6. The muffler of claim 1, wherein: the thickness of the inner wall plate is 0.5-10 mm, the aperture of the hole is 0.1-5 mm, the perforation rate sigma of the hole is 0.1-30%, the width of the micro-slit is 0.01-4 mm, the length of the micro-slit is 1-200 mm, and the perforation rate rho is 0.1-30%.

7. The muffler of claim 1, wherein: the arrangement mode of the holes on the inner wall is consistent with that of the micro-slits, or the arrangement mode of the holes on the inner wall is inconsistent with that of the micro-slits, and the holes and the micro-slits are arranged independently.

8. The muffler of claim 1, wherein: the cavity depth of the closed cavity is 10-1500 mm.

9. The muffler of claim 1, wherein: the length of the pipe is smaller than the cavity depth of the closed cavity or larger than the cavity depth of the closed cavity.

10. The muffler of claim 3, wherein: the thickness of environmental protection sound absorbing material layer is 10 ~ 300 mm.

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