CN203570390U - Integrated type SCR box sound attenuation unit - Google Patents

Abstract

The utility model discloses an integrated SCR box noise reduction element, which comprises a cylinder body with an air inlet pipe at the front end and an air outlet pipe at the rear end. The perforated plate divides the cylinder body into an expansion chamber, an end chamber and a perforated chamber in sequence. A throat pipe connecting the expansion chamber and the end chamber is provided on the upper part of the front perforated plate. The air outlet pipe enters the end chamber through the perforation chamber and the rear perforated plate. The portion of the outlet pipe located in the perforated cavity and the end cavity is evenly distributed with through holes, and the expansion cavity, the end cavity and the perforated cavity are used to make the sudden change in the section of the pipeline cause a change in acoustic impedance, so that a part of the sound waves propagating along the pipeline are reflected back to the sound source and transmitted. The sound energy is reduced to improve its low-frequency acoustic performance; the double-throat structure makes the gas flow area large, the air resistance is small, and the pressure loss caused is relatively small, which can effectively reduce the exhaust back pressure; the air outlet pipe adopts a reed tube structure , reducing high-frequency noise and regenerative noise.

Description

Integrated SCR box silencer element

technical field

The utility model relates to an integrated SCR box noise reduction element.

Background technique

With the increasingly stringent emission regulations, the diesel engine post-treatment technology urea selective catalytic reduction has been more and more widely used in the world. The diesel engine urea SCR system needs to add an SCR catalytic converter to the original diesel engine exhaust system. In practical application In general, the integrated SCR box form that integrates the SCR catalytic converter and the exhaust muffler of the diesel engine is adopted. In the existing SCR muffler, the SCR box body makes the exhaust back pressure of the diesel engine larger due to the carrier, which in turn makes the The power loss increases. In order to reduce the power loss ratio and exhaust back pressure of the diesel engine, its acoustic performance is often sacrificed, so that the insertion loss does not meet the design requirements. The acoustic performance of the SCR muffler is poor. In addition, the engine displacement is mainly concentrated in the Low and medium frequency bands, and high frequency bands also have relatively high energy. Within the limited space of the muffler, better noise reduction effects cannot be obtained in the wide frequency range of low, medium and high frequencies.

At present, the exhaust mufflers of diesel engines in my country mainly use anti-mufflers with different combinations of perforated pipes and expansion chambers, which generally have the problems of poor muffler performance and large exhaust resistance, especially for the comprehensive research work on the acoustic performance and pressure loss of integrated SCR boxes. Relatively few, when developing and designing the integrated SCR box, the noise reduction effect of the muffler, the pressure loss of the exhaust system and its impact on the performance of the SCR system were not considered comprehensively, resulting in the sound suppression level of the SCR box not meeting the design requirements.

Utility model content

The technical problem to be solved by the utility model is to provide an integrated SCR box sound-absorbing element that can effectively reduce exhaust back pressure loss and have a good sound-absorbing effect in view of the above-mentioned defects.

In order to solve the above-mentioned technical problems, the utility model includes a cylinder body with an air inlet pipe at the front end and an air outlet pipe at the rear end, a front perforated plate and a rear perforated plate are arranged in the cylinder body, and the front perforated plate and the rear perforated plate connect the cylinder body It is divided into an expansion chamber, an end chamber and a perforation chamber in turn. Its structural feature is that the upper part of the front perforated plate is provided with a throat connecting the expansion chamber and the end chamber. There is at least one throat, and the outlet pipe passes through the perforation. The cavity and the rear perforated plate enter the final cavity, and the part of the air outlet pipe located in the perforated cavity and the final cavity is evenly distributed with through holes.

The upper part of the front perforated plate is spaced apart from two throats arranged in parallel.

The end of the air outlet pipe located at the end cavity is provided with a diversion port.

The outlet pipe is a reffer tube.

The front perforated board is a double-layer board, and sound-absorbing cotton is sandwiched between the two-layer boards.

The perforated cavity is filled with sound-absorbing cotton.

Compared with the prior art, the integrated SCR box noise reduction element adopting the above scheme has the following advantages: the utility model uses the expansion cavity, the end cavity and the perforation cavity to make the sudden change of the section of the pipeline cause the change of the acoustic impedance, so that a part of the sound wave propagating along the pipeline Reflect back to the sound source, reduce the transmitted sound energy, and improve its low-frequency acoustic performance; the double-throat structure makes the gas flow area large, the air resistance is small, and the pressure loss caused is relatively small, which can effectively reduce the exhaust back pressure; the outlet pipe The reed tube structure is used to reduce high-frequency noise and regenerative noise; considering the temperature and sound absorption effect of the exhaust pipe, high-temperature-resistant ultra-fine glass wool is selected as the sound-absorbing material, which can work normally at high temperatures and eliminates noise. The sound effect is good; the perforated cavity is filled with sound-absorbing cotton, which can increase the thickness and density of the sound-absorbing material, and improve the sound-absorbing effect of medium and low frequencies; the sound-absorbing cotton sandwiched in the front perforated plate is thinner, which can prevent the formation of large exhaust Back pressure, the thicker sound-absorbing cotton used in the perforated cavity can not only make the structure of the whole muffler compact, reduce the weight, but also achieve better sound-absorbing effect without generating a large exhaust back pressure. Moreover, the utility model has the advantages of simple structure, convenient use and good noise reduction effect.

Description of drawings

Below in conjunction with accompanying drawing, the specific embodiment of the present utility model is described in further detail:

Fig. 1 is the structural representation of the utility model;

Fig. 2 is a sectional view along line A-A in Fig. 1 .

Detailed ways

As shown in Figure 1 and Figure 2, the integrated SCR box noise reduction element includes a cylinder body 1 with an air inlet pipe at the front end and an air outlet pipe 14 at the rear end, and a front perforated plate 13 and a rear perforated plate 11 are arranged inside the cylinder body 1 , the front perforated plate 13 and the rear perforated plate 11 divide the cylinder body 1 into the expansion chamber 3, the end chamber 12 and the perforation chamber 8 in sequence, and the upper part of the front perforated plate 13 is provided with a throat 5 communicating with the expansion chamber 3 and the end chamber 12, There is at least one throat 5. In this embodiment, two parallel throats 5 are arranged on the upper part of the front perforated plate 13 at intervals. The double throats 5 make the gas flow area large, the air resistance is small, and the pressure loss caused is relatively small. It can effectively reduce the exhaust back pressure. The air outlet pipe 14 passes through the perforated chamber 8 and the rear perforated plate 11 and enters the end chamber 12 , and the parts of the air outlet pipe 14 located at the perforated chamber 8 and the end chamber 12 are evenly distributed with through holes 9 . The through hole 9 can reduce high-frequency airflow regeneration noise components. The perforated cavity 8 between the rear perforated plate 11 and the end wall of the cylinder body 1 is filled with sound-absorbing cotton 10, and the sound-absorbing cotton 10 is thicker, which can not only make the structure of the whole muffler compact, reduce the weight, but also achieve better sound attenuation effect, and will not generate a large exhaust back pressure. The end of the air outlet pipe 14 located at the end chamber 12 is provided with a diversion port 7, and the diversion port 7 can reduce regenerative noise. The front perforated board 13 is sandwiched with sound-absorbing cotton 6. The front perforated board 13 is composed of two boards. The two boards are evenly distributed with through holes. The sound-absorbing cotton 6 is installed between the two boards. The rear perforated board 11 is a single board. , and through-holes are evenly distributed on the board surface. In this embodiment, the outlet pipe 14 is a reed pipe, and the reed pipe is a concentric pipe with a through hole in the middle.

In this embodiment, the sound-absorbing cotton is selected as ultra-fine glass wool, which can work normally at a high temperature of 1000° C., and has a good sound-absorbing effect.

The utility model is used in this way: the air flow enters the expansion chamber 3 through the air intake pipe, and performs resonance and noise reduction. Most of the air flow after the resonance noise reduction enters the final chamber 12 through two throat pipes 5, and the two throat pipes 5 effectively reduce the pressure loss and increase the pressure loss. Large airflow area, a small part of the airflow passes through the front perforated plate 13 and sound-absorbing cotton 13 and enters the final chamber 12. The perforated plate 13 has a high porosity and small aperture, and through sound wave reflection and friction, it can effectively reduce high-frequency sound wave energy. 12 facilitates low-frequency sound wave reflection and mixing of medium and high-frequency sound waves. Part of the airflow in the final cavity 12 enters the perforated cavity 8 through the rear perforated plate 11, and the middle and high-frequency noise and regenerative noise are silenced by the sound-absorbing cotton 10 in the perforated cavity 8. The airflow passes through After the sound-absorbing cotton 10 is silenced, it enters the outlet pipe 14 through the through hole 9 on the outlet pipe 14 and is discharged. Another part of the airflow in the end chamber 12 enters the outlet pipe 14 through the diversion port 7 and the through hole 9 on the outlet pipe 14, and enters the outlet pipe 14. Part of the air flow behind the air pipe 14 is directly discharged, and the other part enters the sound-absorbing cotton 10 through the through hole 9 and is discharged after being silenced.

The utility model is not limited to the above-mentioned specific embodiments, and those skilled in the art can make some changes and modifications without departing from the spirit and scope of the utility model. The protection scope of the utility model should be based on the claims of the utility model.

Claims (6)

1. an integrated form SCR case silencer element, comprise that front end is provided with suction tude, rear end is provided with the cylindrical shell (1) of steam outlet pipe (14), in described cylindrical shell (1), be provided with front perforated plate (13) and rear perforated plate (11), front perforated plate (13) and rear perforated plate (11) are separated into expansion cavity (3) successively by cylindrical shell (1), chamber (12), end and perforated chamber (8), the top that it is characterized in that described front perforated plate (13) is provided with the trunnion (5) that is communicated with expansion cavity (3) and last chamber (12), described trunnion (5) is at least one, described steam outlet pipe (14) enters last chamber (12) through perforated chamber (8) and rear perforated plate (11), the part that described steam outlet pipe (14) is positioned at perforated chamber (8) and last chamber (12) is evenly equipped with through hole (9).

2. integrated form SCR case silencer element according to claim 1, is characterized in that described front perforated plate (13) top is interval with two trunnions that be arranged in parallel (5).

3. according to the integrated form SCR case silencer element described in any one in claim 1-2, it is characterized in that the end that described steam outlet pipe (14) is positioned at last chamber (12) is provided with flow-guiding mouth (7).

4. integrated form SCR case silencer element according to claim 1, is characterized in that described steam outlet pipe (14) not manages for reed.

5. integrated form SCR case silencer element according to claim 1, is characterized in that described front perforated plate (13) is doubling plate, has clamped acoustical cotton (6) between two-ply.

6. integrated form SCR case silencer element according to claim 1, is characterized in that being filled with in described perforated chamber (8) silencing cotton (10).

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