CN101466251A - Air-out noise reducer and system - Google Patents

Abstract

Embodiments of the present invention provide a wind outlet noise reduction device and system. The wind outlet noise reduction device has an inner layer and an outer layer, and the outer layer is surrounded by the outer wall of the top wall, the outer wall of the first side wall, and the outer wall of the second side wall. Formed, and the sound-absorbing structure is attached to the inner side of the outer layer. An interlayer is arranged between the inner wall of the top wall and the outer wall of the top wall to form an inverted U-shaped first air outlet channel that runs through both ends. The outer wall of the second side wall is provided with a first air port, and the inner wall of the second side wall is provided with a second air port and a third air port. The first air inlet channel is formed between the first air outlet and the second air outlet, the second air inlet channel is formed between the first air outlet and the third air outlet, and the first air inlet channel and the second air inlet channel The channel forms an upper and lower air intake path. The embodiments of the present invention extend the air duct structure of the cabinet under the premise of effective ventilation and reduce equipment noise by using air ducts such as upper and lower split air inlet ducts and inverted U-shaped outflow air ducts.

Description

Air outlet noise reduction device and system

technical field

The invention relates to a wind noise reduction device and system, in particular to a wind noise reduction device and system for a communication cabinet.

Background technique

With the rapid development of communication cabinet manufacturing technology, people have higher and higher noise requirements for cabinets. Due to its high integration and compact structure, the communication equipment inside the cabinet often brings high noise when using air cooling for heat dissipation.

As shown in FIG. 1A and FIG. 1B , the prior art 1 is to use the same sound-absorbing structure 120 at the position of the air inlet and outlet of the side wall 110 of the cabinet as the opening of the air inlet and outlet. However, the opening of the sound-absorbing structure in the prior art 1 is inconvenient and costly, and the noise-reducing performance of the sound-absorbing structure after opening is reduced, and the sound power level noise reduction effect of the noise reduction scheme is less than 2dB.

In the prior art 2 shown in Fig. 2A and Fig. 2B, a cross-flow channel structure is used inside the side wall 210 of the cabinet, and a sound-absorbing structure is attached to the sound-absorbing structure 220 inside the side wall 210 of the cabinet to reduce the noise of the cabinet. This solution diverts the straight airflow through the rectangular or trapezoidal sound-absorbing structural member 220 , and the airflow enters the inside of the cabinet from both sides of the sound-absorbing structural member 220 ; the corresponding airflow flows out from both sides of the sound-absorbing structural member 220 . While avoiding straight in and out of the air duct, sound absorption and noise reduction are performed through the sound absorption structure on the sound attenuation structure 220 . However, in the second prior art, the air flow enters the cabinet from both sides of the noise-absorbing structural member 220, reducing the air volume in the middle slot, which becomes a heat dissipation bottleneck and affects the heat dissipation of the cabinet. In addition, the anechoic channel in the second prior art is relatively short, and the sound power level noise reduction effect is not obvious.

Contents of the invention

Embodiments of the present invention provide a wind noise reduction device and system for reducing cabinet noise.

An embodiment of the present invention provides a wind outlet noise reduction device, the wind outlet noise reduction device includes a top wall, a first side wall and a second side wall; the wind outlet noise reduction device has an inner layer and an outer layer; The inner layer of the noise reduction device is surrounded by the inner wall of the top wall, the inner wall of the first side wall and the inner wall of the second side wall; the outer layer of the noise reduction device is composed of the outer wall of the top wall, the outer wall of the first side wall and The outer side wall of the second side wall is surrounded by a sound-absorbing structure attached to the inner side of the outer layer of the wind outlet noise reduction device;

An interlayer is arranged between the inner wall of the top wall and the outer wall of the top wall to form an inverted U-shaped first air outlet duct that runs through both ends. One end of the first air outlet air duct leads to the outside of the side wall of the air outlet noise reduction device. The other end of the air outlet duct leads to the inside of the air outlet noise reduction device;

An interlayer is arranged between the inner side wall of the first side wall and the outer side wall of the first side wall to form a second air outlet duct that runs through both ends. One end of the second air outlet duct leads to the outer side wall of the air outlet noise reduction device. The other end of the air outlet duct leads to the inside of the air outlet noise reduction device;

An interlayer is arranged between the inner wall of the second side wall and the outer wall of the second side wall, the outer wall of the second side wall is provided with a first air port, the inner wall of the second side wall is provided with a second air port and a third air port, and the second air port and the third air outlet are arranged on the upper and lower sides of the first air outlet; the first air inlet duct is formed between the first air outlet and the second air outlet, and the second air inlet air duct is formed between the first air outlet and the third air outlet , the first air inlet duct and the second air inlet duct form an upper and lower air inlet path.

An embodiment of the present invention also provides a stacked cabinet air outlet noise reduction system, including: an upper cabinet, a lower cabinet, and an air outlet noise reduction device covering the upper cabinet and the lower cabinet, wherein,

The surface of the upper cabinet is provided with at least one first air outlet chamber and one first air inlet chamber, and the first air outlet chamber and the first air inlet chamber are connected inside the cabinet;

The lower cabinet is placed under the upper cabinet, and the surface of the lower cabinet is provided with at least one second air outlet chamber and one second air inlet chamber; the second air outlet chamber and the second air inlet chamber are inside the cabinet Connected;

The interior of the wind noise reduction device is hollow, and the wind noise reduction device includes a top wall, a first side wall and a second side wall; the wind noise reduction device has an inner layer and an outer layer; the wind noise reduction device The inner layer is surrounded by the inner wall of the top wall, the inner wall of the first side wall and the inner wall of the second side wall; The outer wall of the wall is surrounded and formed, and the inner side of the outer layer of the wind outlet noise reduction device is attached with a sound-absorbing structure;

An interlayer is arranged between the inner wall of the top wall and the outer wall of the top wall to form an inverted U-shaped first air outlet duct that runs through both ends. One end of the first air outlet air duct leads to the outside of the side wall of the air outlet noise reduction device. The other end of the air outlet duct leads to the inside of the air outlet noise reduction device and communicates with the first air outlet chamber of the upper cabinet;

An interlayer is arranged between the inner side wall of the first side wall and the outer side wall of the first side wall to form a second air outlet duct that runs through both ends. One end of the second air outlet duct leads to the outer side wall of the air outlet noise reduction device. The other end of the second air outlet duct leads to the inside of the air outlet noise reduction device and communicates with the second air outlet chamber of the lower cabinet;

An interlayer is arranged between the inner wall of the second side wall and the outer wall of the second side wall, the outer wall of the second side wall is provided with a first air port, the inner wall of the second side wall is provided with a second air port and a third air port, and the second air port and the third air outlet are arranged on the upper and lower sides of the first air outlet; the first air inlet duct is formed between the first air outlet and the second air outlet, and the second air inlet air duct is formed between the first air outlet and the third air outlet , the first air inlet duct and the second air inlet duct form an upper and lower air inlet path.

The air outlet noise reduction device and system provided by the embodiments of the present invention use air ducts such as upper and lower split air inlet ducts and inverted U-shaped outflow air ducts to extend the cabinet air duct structure and reduce equipment noise under the premise of effective ventilation.

Description of drawings

Fig. 1A is a three-dimensional view of the combined structure of the cabinet side wall and the sound-absorbing structure in the prior art 1;

Fig. 1B is a cross-sectional view of the combined structure of the cabinet side wall and the sound-absorbing structure in prior art 1;

Fig. 2A is a schematic diagram of the internal structure of the combination of the cabinet side wall and the sound-absorbing structure in the prior art 2;

FIG. 2B is a schematic structural diagram of a prior art 2 cabinet;

Fig. 3 is a schematic structural diagram of a wind outlet noise reduction device according to an embodiment of the present invention;

Fig. 4 is a perspective view of the air outlet noise reduction device according to the embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a wind outlet noise reduction device according to another embodiment of the present invention;

Fig. 6 is a schematic structural diagram of a wind-out noise reduction system according to an embodiment of the present invention;

Fig. 7 is a perspective view of the air outlet noise reduction system according to the embodiment of the present invention;

Fig. 8 is a schematic structural diagram of a wind outlet noise reduction system according to another embodiment of the present invention.

Detailed ways

Please refer to FIG. 3 and FIG. 4 together. The air outlet noise reduction device 300 of the embodiment of the present invention is hollow inside, and the air outlet noise reduction device 300 includes a top wall 310 , a first side wall 330 and a second side wall 320 . The wind noise reduction device 300 has an inner layer and an outer layer. The top wall 310 includes a top wall inner wall 311 and a top wall outer wall 312 . The first side wall 330 includes a first side wall inner wall 331 and a first side wall outer wall 332 ; the second side wall 320 includes a second side wall inner wall 321 and a second side wall outer wall 322 . It can be understood that the inner layer of the wind outlet noise reduction device 300 is surrounded by the inner wall 311 of the top wall, the inner wall 331 of the first side wall and the inner wall 321 of the second side wall; , The outer wall 332 of the first side wall and the outer wall 322 of the second side wall are surrounded and formed.

The inner side of the air outlet noise reduction device 300 accommodates a cabinet, and the cabinet may have a first air inlet chamber, a first air outlet chamber, a second air inlet chamber and a second air outlet chamber. The sound-absorbing structure 340 is attached to the inner side of the outer layer of the wind outlet noise reduction device 300, and in this embodiment, the outer side wall 312 of the top wall, the outer side wall 332 of the first side wall, and the outer side wall 322 of the second side wall are attached to the sound-absorbing structure 340.

Between the inner side wall 311 of the top wall and the outer side wall 312 of the top wall, there is an inverted U-shaped first air outlet duct 314 formed at both ends, and one end of the first air outlet duct 314 leads to the side of the air outlet noise reduction device 300 Outside the wall, the other end of the first air outlet duct leads to the inside of the air outlet noise reduction device 300 and communicates with the first air outlet chamber of the cabinet;

A second air outlet duct 334 is interposed between the inner side wall 331 of the first side wall and the outer side wall 332 of the first side wall to form a second air outlet duct 334 that runs through at both ends, and one end of the second air outlet duct 334 leads to the side of the air outlet noise reduction device 300 Outside the wall, the other end of the second air outlet channel leads to the inside of the air outlet noise reduction device 300;

The inner wall 321 of the second side wall and the outer wall 322 of the second side wall are interlayered. tuyere 326, and the second tuyere 324 and the third tuyere 326 are arranged on the upper and lower sides of the first tuyere 323; the first air inlet duct 327 is formed between the first tuyere 321 and the second tuyere 324, the first tuyere 321 and the The second air inlet duct 328 is formed between the third air outlets 326 , and the first air inlet duct 327 and the second air inlet duct 328 form an upper and lower air inlet path. Optionally, the sound-absorbing structure 340 in this embodiment 1 is a micro-perforated plate, a space absorbing body, etc., and the sound-absorbing material used in the sound-absorbing structure 340 can be glass wool, organic fiber, inorganic fiber, foam sound-absorbing material, metal absorbing material, etc. sound material etc.

When the air outlet noise reduction device 300 of the embodiment of the present invention is in operation, the external air flows up and down through the first air outlet 323 and enters the first air inlet channel 327 and the second air inlet channel 328 respectively. The air entering the first air inlet duct 327 passes through the sound-absorbing structure 340 attached to the inner side of the second side wall outer wall 322 , enters the interior of the air outlet noise reduction device 300 through the second air port 324 , and is released in the air outlet noise reduction device 300 . After the internal cabinet of the device 300 circulates and dissipates heat, it flows out of the noise reduction device 300 through an inverted U-shaped first air outlet duct 314 formed between the inner wall 311 and the outer wall 312 of the top wall. The air entering the second air inlet duct 328 passes through the sound-absorbing structure 340 attached to the inner side of the second side wall outer wall 322, and then enters the interior of the air outlet noise reduction device 300 through the third air port 326, and is discharged in the air outlet. After the internal cabinet of the noise reduction device 300 circulates and dissipates heat, it flows out of the noise reducing device 300 through the second air outlet duct 334 interposed between the inner side wall 331 of the first side wall and the outer wall 332 of the first side wall.

The air outlet noise reduction device 300 provided by Embodiment 1 of the present invention uses the upper and lower split air inlet air ducts 327, 328 and the inverted U-shaped air outlet air duct 314 to extend the internal cabinet air duct structure on the premise of effective ventilation. Reduce cabinet noise.

Optionally in this embodiment, the wind noise reduction device 300 also includes a third side wall and a fourth side wall; the top wall, the first side wall, the second side wall, and the third side wall (not shown in the figure) and the fourth side wall (not shown in the figure) form a rectangular column wind-out noise reduction device with a bottom through and a hollow interior. The cabinet can then be inserted from the bottom of the air outlet noise reduction device.

Please also refer to FIG. 5 , the air outlet noise reduction device also includes a base 630. After the cabinet is inserted from the bottom of the air outlet noise reduction device, it passes through the top wall 310, the base 630, the first side wall 330, and the second side. The wall 320 , the third side wall (not shown in the figure) and the fourth side wall (not shown in the figure) enclose a cylindrical air outlet noise reduction device with a sealed bottom and a hollow interior.

In this embodiment, the first side wall and the second side wall of the air outlet noise reduction device are curved surfaces, the first side wall and the second side wall form a cylindrical cavity, and the top wall cover is placed on the top of the cylinder. Furthermore, the inside of the internal air outlet noise reduction device can accommodate a cylindrical cabinet. Of course, the air outlet noise reduction device in this embodiment is not limited to a specific shape, as long as the side wall of the air outlet noise reduction device is divided into upper and lower air inlets. The air duct, under the premise of effective ventilation, extends the internal cabinet air duct structure, which can effectively reduce the noise of the cabinet.

Please refer to Fig. 6 and Fig. 7 together. This embodiment discloses an air outlet noise reduction system, including: an upper cabinet 610, a lower cabinet 620, and an air outlet noise reduction device 300 covering the upper cabinet 610 and the lower cabinet 620. in,

The surface of the upper cabinet 610 is provided with at least one first air outlet chamber 613 and one first air inlet chamber 611, and the first air outlet chamber 613 and the first air inlet chamber 611 are connected inside the cabinet;

The lower cabinet 620 is placed under the upper cabinet 610, and the surface of the lower cabinet 620 is provided with at least one second air outlet chamber 623 and one second air inlet chamber 621; the second air outlet chamber 623 and the second The air inlet cavity 621 is connected inside the cabinet;

The air outlet noise reduction device 300 is hollow inside, and the air outlet noise reduction device 300 includes a top wall 310 , a first side wall 330 and a second side wall 320 . The wind noise reduction device 300 has an inner layer and an outer layer. The top wall 310 includes a top wall inner wall 311 and a top wall outer wall 312 . The first side wall 330 includes a first side wall inner wall 331 and a first side wall outer wall 332 ; the second side wall 320 includes a second side wall inner wall 321 and a second side wall outer wall 322 . It can be understood that the inner layer of the wind outlet noise reduction device 300 is surrounded by the inner wall 311 of the top wall, the inner wall 331 of the first side wall and the inner wall 321 of the second side wall; , The outer wall 332 of the first side wall and the outer wall 322 of the second side wall are surrounded and formed.

The upper cabinet 610 and the lower cabinet 620 are accommodated inside the inner layer of the wind outlet noise reduction device 300 . A sound-absorbing structure 340 is attached to the inside of the outer layer of the wind-outlet noise reduction device 300 .

Between the inner side wall 311 of the top wall and the outer side wall 312 of the top wall, there is an inverted U-shaped first air outlet duct 314 formed at both ends, and one end of the first air outlet duct 314 leads to the side of the air outlet noise reduction device 300 Outside the wall, the other end of the first air outlet duct leads to the inside of the air outlet noise reduction device 300 and communicates with the first air outlet chamber 613 of the upper cabinet 610 .

A second air outlet duct 334 is interposed between the inner side wall 331 of the first side wall and the outer side wall 332 of the first side wall to form a second air outlet duct 334 that runs through at both ends, and one end of the second air outlet duct 334 leads to the side of the air outlet noise reduction device 300 Outside the wall, the other end of the second air outlet duct leads to the inside of the air outlet noise reduction device 300 and communicates with the second air outlet chamber 623 of the lower cabinet 620 .

The inner wall 321 of the second side wall and the outer wall 322 of the second side wall are interlayered. tuyere 326, and the second tuyere 324 and the third tuyere 326 are arranged on the upper and lower sides of the first tuyere 323; the first air inlet duct 327 is formed between the first tuyere 321 and the second tuyere 324, the first tuyere 321 and the The second air inlet duct 328 is formed between the third air outlets 326 , and the first air inlet duct 327 and the second air inlet duct 328 form an upper and lower air inlet path.

When the air outlet noise reduction system of the embodiment of the present invention is working, the external air flows up and down through the first air outlet 323 and enters the first air inlet channel 327 and the second air inlet channel 328 respectively. The air entering the first air inlet duct 327 passes through the sound-absorbing structure 340 attached to the inner side of the second side wall outer wall 322 , enters the interior of the air outlet noise reduction device 300 through the second air port 324 , and passes through the upper cabinet 610 first. One air inlet chamber 611 enters, and flows out of the upper cabinet 610 through the first air outlet chamber 613; The first air outlet duct 314 forming an inverted U-shape penetrating at both ends flows out of the air outlet noise reduction device 300 . The air entering the second air inlet duct 328 passes through the sound-absorbing structure 340 attached to the inner side of the second side wall outer wall 322 , enters the interior of the air outlet noise reduction device 300 through the third air port 326 , and passes through the lower cabinet 620 The second air inlet chamber 621 enters, and flows out of the upper cabinet 610 through the second air outlet chamber 623; and after circulating heat in the lower cabinet 620 inside the air outlet noise reduction device 300, it passes through the inner side wall 331 of the first side wall and the outer side of the first side wall A second air outlet duct 334 is interposed between the walls 332 to flow out of the air outlet noise reduction device 300 .

The air outlet noise reduction system provided by the embodiment of the present invention uses the upper and lower split air inlet air ducts 327, 328, and the inverted U-shaped air outlet air duct 314. On the premise of effective ventilation, the internal upper and lower cabinet air duct structures are extended, reducing Cabinet noise.

The optional air outlet noise reduction system in this embodiment can also use the air outlet noise reduction device 300 disclosed in Embodiment 1. It also includes a third side wall and a fourth side wall; the top wall, the first side wall, the second side wall The second side wall, the third side wall and the fourth side wall form a wind outlet noise reduction device with a bottom through and a hollow inside. The cabinet can then be inserted from the bottom of the air outlet noise reduction device.

Optionally, the air outlet noise reduction device further includes a base 630. After the upper cabinet 610 and the lower cabinet 620 are inserted from the bottom of the air outlet noise reduction device, they pass through the top wall 310, the base 630, the first side wall 330, The second side wall 320 , the third side wall (not shown in the figure) and the fourth side wall (not shown in the figure) enclose a bottom-sealed and hollow air outlet noise reduction device.

Optionally, the first side wall and the second side wall of the air outlet noise reduction device are curved surfaces, the first side wall and the second side wall form a cylindrical cavity, and the top wall cover is placed on the top of the cylinder. Furthermore, the inside of the internal air outlet noise reduction device can accommodate a cylindrical cabinet. Of course, the air outlet noise reduction device in this embodiment is not limited to a specific shape, as long as the side wall of the air outlet noise reduction device is divided into upper and lower air inlets. Air duct, under the premise of effective ventilation, the internal cabinet air duct structure is extended, which can effectively reduce the noise of the cabinet

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. Should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (10)

1, a kind of air-out noise reducer is characterized in that, air-out noise reducer comprises roof, the first side wall and second sidewall; Described air-out noise reducer has internal layer and skin; Described air-out noise reducer internal layer is enclosed by roof madial wall, the first side wall madial wall and the second inside sidewalls wall and forms; Described air-out noise reducer skin is enclosed by roof lateral wall, the first side wall lateral wall and the second sidewall lateral wall and forms, the outer inboard sound absorption structure that attaches of described air-out noise reducer;

Interlayer setting between roof madial wall and the roof lateral wall, the first air-out air channel of the inverted U that formation two connects, the described first air-out air channel one end leads to the air-out noise reducer sidewall outside, and the first air-out air channel other end leads to air-out noise reducer inside;

Interlayer setting between the first side wall madial wall and the first side wall lateral wall forms the second air-out air channel that two connects, and the described second air-out air channel one end leads to the air-out noise reducer sidewall outside, and the second air-out air channel other end leads to air-out noise reducer inside;

Interlayer setting between the second inside sidewalls wall and the second sidewall lateral wall, the second sidewall lateral wall is provided with first air port, and the second inside sidewalls wall is provided with second air port and the 3rd air port, and second air port and the 3rd air port are arranged at both sides up and down, first air port; Form described first wind inlet channel between first air port and second air port, form described second wind inlet channel between first air port and the 3rd air port, first wind inlet channel and second wind inlet channel form the air intake path of shunting up and down.

2, air-out noise reducer as claimed in claim 1 is characterized in that, described air-out noise reducer also comprises the 3rd sidewall and the 4th sidewall; Described roof, diapire, the first side wall, second sidewall, the 3rd sidewall and the 4th sidewall surround the air-out noise reducer that forms bottom perforation and inner hollow.

3, air-out noise reducer as claimed in claim 1 is characterized in that, described air-out noise reducer also comprises diapire, the 3rd sidewall and the 4th sidewall; Described roof, diapire, the first side wall, second sidewall, the 3rd sidewall and the 4th sidewall surround the air-out noise reducer that forms bottom sealing and inner hollow.

4, air-out noise reducer as claimed in claim 1, it is characterized in that, described sound absorption structure is microperforated panel or suspended absorber, and the sound-absorbing material that described sound absorption structure is used is mineral wool, organic fiber, inorfil, foamed sound-absorbing material or metal sound-absorbing material.

5, air-out noise reducer as claimed in claim 1 is characterized in that, the first side wall of described air-out noise reducer and second sidewall are cambered surface, and the first side wall and second sidewall form the cylinder die cavity, and the roof lid places the column type top.

6, a kind of rack air-out noise reduction system of piling up is characterized in that, comprising: go up rack, following rack and coat the air-out noise reducer of going up rack and following rack, wherein,

The described rack surface of going up is provided with 1 first air-out chamber and 1 first air-inlet cavity at least, and described first air-out chamber and described first air-inlet cavity are connected in rack inside;

Described rack down places the rack below, and following rack surface is provided with 1 second air-out chamber and 1 second air-inlet cavity at least; Described second air-out chamber and described second air-inlet cavity are connected in rack inside;

Described air-out noise reducer comprises roof, the first side wall and second sidewall; Described air-out noise reducer has internal layer and skin; Described air-out noise reducer internal layer is enclosed by roof madial wall, the first side wall madial wall and the second inside sidewalls wall and forms; Described air-out noise reducer skin is enclosed by roof lateral wall, the first side wall lateral wall and the second sidewall lateral wall and forms, the outer inboard sound absorption structure that attaches of described air-out noise reducer;

Interlayer setting between roof madial wall and the roof lateral wall, form the first air-out air channel of the inverted U of two perforation, the described first air-out air channel one end leads to the air-out noise reducer sidewall outside, the first air-out air channel other end lead to air-out noise reducer inner and with the last rack first air-out chamber UNICOM;

Interlayer setting between the first side wall madial wall and the first side wall lateral wall, form the second air-out air channel that two connects, the described second air-out air channel one end leads to the air-out noise reducer sidewall outside, the second air-out air channel other end lead to air-out noise reducer inner and with the following rack second air-out chamber UNICOM;

Interlayer setting between the second inside sidewalls wall and the second sidewall lateral wall, the second sidewall lateral wall is provided with first air port, and the second inside sidewalls wall is provided with second air port and the 3rd air port, and second air port and the 3rd air port are arranged at both sides up and down, first air port; Form described first wind inlet channel between first air port and second air port, form described second wind inlet channel between first air port and the 3rd air port, first wind inlet channel and second wind inlet channel form the air intake path of shunting up and down.

7, system as claimed in claim 6 is characterized in that, described air-out noise reducer also comprises the 3rd sidewall and the 4th sidewall; Described roof, diapire, the first side wall, second sidewall, the 3rd sidewall and the 4th sidewall surround the air-out noise reducer that forms bottom perforation and inner hollow.

8, system as claimed in claim 6 is characterized in that, described air-out noise reducer also comprises diapire, the 3rd sidewall and the 4th sidewall; Described roof, diapire, the first side wall, second sidewall, the 3rd sidewall and the 4th sidewall surround the air-out noise reducer that forms bottom sealing and inner hollow.

9, system as claimed in claim 6 is characterized in that, described sound absorption structure is a microperforated panel.

10, system as claimed in claim 6 is characterized in that, the first side wall of described air-out noise reducer and second sidewall are cambered surface, and the first side wall and second sidewall form the cylinder die cavity, and the roof lid places the column type top.

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