阅读说明：本技术 一种适应进风参数性能可调优的*** (Silencer with adjustable and excellent performance adapting to air inlet parameters ) 是由 孔伟涛 周超 夏鹏鹏 莫登沅 于 2019-09-20 设计创作，主要内容包括：本发明公开了一种适应进风参数性能可调优的消声器,包括固定安装装置,包括消声器外壳(6)及设于该消声器外壳(6)两端的法兰(1),至少一个消声片(2),该消声片(2)设于所述固定安装装置内,包括消声片本体及设于该消声片本体两端的导流罩(205),同步驱动装置,其设于所述固定安装装置外端面侧,穿过该固定安装装置外壁与所述消声片(2)连接,包括至少一根连杆(3)、设于该连杆(3)上至少一个转轴(5),对应每个消声片(2)的转轴(5)外端部设有驱动机构(7)。本发明的消声器,可对插入损失进行调节,转动的角度越大,插入损失越高,降噪量越高,实时根据风量及流速调节消声片的角度,提高消声性能和空气动力性能。(The invention discloses a muffler with adjustable and excellent performance suitable for air inlet parameters, which comprises a fixed mounting device, a muffler shell (6), flanges (1) arranged at two ends of the muffler shell (6), at least one silencing sheet (2), a silencing sheet (2) arranged in the fixed mounting device, a silencing sheet body, flow guide covers (205) arranged at two ends of the silencing sheet body, and a synchronous driving device arranged on the outer end face side of the fixed mounting device and connected with the silencing sheet (2) by penetrating through the outer wall of the fixed mounting device, wherein the synchronous driving device comprises at least one connecting rod (3), at least one rotating shaft (5) arranged on the connecting rod (3), and a driving mechanism (7) is arranged at the outer end part of the rotating shaft (5) corresponding to each silencing sheet (2). The silencer can adjust the insertion loss, the larger the rotation angle is, the higher the insertion loss is, the higher the noise reduction is, the angle of the silencing sheet can be adjusted according to the air volume and the flow rate in real time, and the silencing performance and the aerodynamic performance are improved.)

1. The utility model provides a silencer that adaptation air inlet parameter performance can be optimized which characterized in that includes:

the fixed mounting device comprises a silencer shell (6) and flanges (1) arranged at two ends of the silencer shell (6), wherein the silencer shell (6) is used as a mounting base body of a silencer, and is fixedly connected with an external mechanism to be silenced through the flanges (1);

the silencing piece (2) is arranged in the fixed mounting device and comprises a silencing piece body and air guide covers (205) arranged at two ends of the silencing piece body, and an included angle between the air guide covers (205) and the air inlet direction of an external mechanism to be silenced is adjusted within the range of-45 degrees to +45 degrees in real time according to the actual air quantity and flow rate; and the number of the first and second groups,

the synchronous driving device is arranged on the outer end face side of the fixed mounting device, penetrates through the outer wall of the fixed mounting device and is connected with the silencing piece (2), comprises at least one connecting rod (3) and at least one rotating shaft (5) arranged on the connecting rod (3), the rotating shaft (5) penetrates through a through hole in the silencing piece (2) and is fixed in the fixed mounting device, a driving mechanism (7) is arranged at the outer end part of the rotating shaft (5) corresponding to each silencing piece (2), so that under the action of the driving mechanism (7), the silencing piece (2) is driven to rotate around the rotating shaft (5), and the insertion loss of the silencer is adjusted in real time.

2. The muffler with adjustable performance according to the intake air parameters of claim 1, wherein the plurality of muffling sheets (2) are arranged in parallel to form a group, a plurality of groups of muffling sheets (2) are arranged in the fixed mounting device, and the muffling sheets (2) in each group are arranged in parallel or at a certain included angle.

3. The muffler with the adjustable and excellent performance of the adaptive air intake parameter as claimed in claim 1 and 2, wherein the outermost layer of the muffler body is coated with a damping mesh (201), and the damping mesh (201) is made of nonmetal or damping material and punched.

4. The muffler with the performance being optimized according to the intake air parameters of claim 1 or 3, wherein the muffler body comprises a protective layer made of glass fiber cloth/non-woven fabric (202) arranged in the damping mesh sheet (201).

5. The muffler with the performance being optimized according to the air intake parameters of claim 1, 3 or 4, characterized in that the muffler body comprises a keel (203) arranged in the glass fiber cloth/non-woven fabric (202), and the keel (203) comprises a plurality of rectangular frame structures.

6. The muffler with the performance being optimized according to the intake air parameters of any one of claims 1 or 3 to 5, wherein the muffler body comprises a sound absorption layer made of sound absorption materials (204) arranged in the keel (203).

7. The muffler with the adjustable performance adapted to the air inlet parameters of claim 6, wherein the muffler body is a rectangular ring structure, two ends of the muffler body are connected with the air guide sleeve (205), and the air guide sleeve (205) is a streamline arc structure.

8. The muffler with the adjustable performance according to the intake air parameters of claim 1, wherein the synchronous driving device comprises a latch (4), the latch (4) is disposed corresponding to the rotating shaft (5) and forms an E-shaped link mechanism together with the connecting rod (3).

9. The muffler with adjustable performance according to the intake air parameters of claim 1 or 2, wherein the muffler shell (6) is a main structure of a fixed installation device, the whole muffler shell is of a rectangular tubular structure, and the periphery of the pipe wall of the muffler shell is provided with a plurality of reinforcing plates of the ring pipe wall.

10. A muffler with adjustable performance according to the intake air parameters of claim 1 or 2, characterized in that the flange (1) has a rectangular ring structure as a whole, has a size matched with the muffler shell (6), and is fixedly mounted on the muffler shell (6) by welding or bolt sealing.

Technical Field

The invention belongs to the technical field of ventilation and noise elimination mechanical equipment, and particularly relates to a muffler with adjustable performance and adaptive to air inlet parameters.

Background

In a ventilation system, a silencer is generally arranged in front of and behind a fan. The muffler is a device which can not only make the air flow pass through smoothly, but also reduce the noise effectively, therefore, the muffler must meet two performance indexes of ventilation and noise elimination. Generally, ventilation performance, also called aerodynamic performance, is one of important indexes for evaluating the performance of the muffler and is also a factor to be considered in the design of the muffler. The conventional silencer generally obtains smaller silencing amount by losing larger wind resistance or obtains smaller wind resistance by losing larger silencing performance, and the compatibility of the silencing performance and the aerodynamic performance is poor.

The existing silencer is a static silencer, namely, no moving part exists in the silencer, once the silencer is installed, the insertion loss performance of the silencer cannot be changed along with the change of air volume, but the air volume in most ventilation systems can be changed through a valve device according to needs. As the air volume increases, the aerodynamic noise generated by the fan becomes larger, the insertion loss of the silencer does not change, but the regenerative noise increases, so that the noise reduction amount of the actual silencer decreases. Furthermore, as the life of the muffler increases, the insertion loss of the muffler also decreases. And a large amount of manpower and material resources are consumed for replacing the silencer, and the material waste is also caused. Ventilation muffling systems are generally limited in installation size and often require a relatively small size with a relatively large amount of muffling. In addition, the action frequency band range of the silencer is generally narrow, and the requirement of noise reduction can be met by performing accurate matching calculation according to data such as heating and ventilation drawing paper and noise spectrum of a fan. The current stationary mufflers on the market are difficult to overcome.

Disclosure of Invention

Aiming at the defects or the improvement requirements of the prior art, the invention provides the silencer with the adjustable and excellent performance of the adaptive air inlet parameters, the silencing pieces are uniformly arranged in the fixed mounting device, the synchronous driving device is arranged on the outer end face side of the fixed mounting device and penetrates through the outer wall of the fixed mounting device to be connected with the silencing pieces so as to synchronously drive the silencing pieces, and therefore, the insertion loss of the silencer with the compatible silencing performance and aerodynamic performance is adjusted. The larger the rotating angle is, the higher the insertion loss is, the higher the noise reduction amount is, and the problems that the noise reduction requirement cannot be met due to the fact that the air volume of a ventilation system passing through a silencer is increased, the pneumatic noise is increased, and the acoustic performance of the silencer is reduced along with the increase of the service life can be avoided.

In order to achieve the above object, the present invention provides a muffler with adjustable performance adapted to intake parameters, comprising:

the fixed mounting device comprises a silencer shell and flanges arranged at two ends of the silencer shell, wherein the silencer shell is used as a mounting base body of the silencer and is fixedly connected with an external mechanism to be silenced through the flanges;

the silencing piece is arranged in the fixed mounting device and comprises a silencing piece body and flow guide covers arranged at two ends of the silencing piece body, and an included angle between the flow guide covers and the air inlet direction of an external mechanism to be silenced is adjusted within the range of-45 degrees to +45 degrees in real time according to the actual air quantity and flow rate; and the number of the first and second groups,

the synchronous driving device is arranged on the outer end face side of the fixed mounting device, penetrates through the outer wall of the fixed mounting device and is connected with the silencing pieces, the synchronous driving device comprises at least one connecting rod and at least one rotating shaft arranged on the connecting rod, the rotating shaft penetrates through a through hole in each silencing piece to fix the rotating shaft in the fixed mounting device, and a driving mechanism is arranged corresponding to the outer end part of each rotating shaft of each silencing piece so as to drive the silencing pieces to rotate around the rotating shaft under the action of the driving mechanism and adjust the insertion loss of the silencer in real time.

Furthermore, a plurality of the silencing pieces are arranged in parallel to form a group, a plurality of groups of the silencing pieces are arranged in the fixed mounting device, and the silencing pieces of each group are arranged in parallel or form a certain included angle.

Furthermore, the outermost layer of the silencing sheet body is coated with a damping mesh sheet, and the damping mesh sheet is prepared from nonmetal or damping materials and is formed by punching.

Furthermore, the silencing sheet body comprises a protective layer which is arranged in the damping net sheet and is composed of glass fiber cloth/non-woven fabric.

Further, the silencing sheet body comprises a keel arranged in the glass fiber cloth/non-woven fabric, and the keel comprises a plurality of rectangular frame structures.

Further, the sound-absorbing sheet body comprises a sound-absorbing layer which is arranged in the keel and is made of sound-absorbing materials.

Furthermore, the silencing piece body is of a rectangular annular structure, two ends of the silencing piece body are connected with the air guide sleeve, and the air guide sleeve is of a streamline arc structure.

Further, the synchronous driving device comprises a lock catch, the lock catch is arranged corresponding to the rotating shaft and forms an E-shaped link mechanism together with the connecting rod.

Furthermore, the silencer shell is a main body structure of the fixed mounting device, the whole silencer shell is of a rectangular tubular structure, and the periphery of the pipe wall of the silencer shell is provided with a plurality of reinforcing plates with annular pipe walls.

Further, the flange is a rectangular ring structure as a whole, the size of the flange is matched with that of the silencer shell, and the flange is fixedly arranged on the silencer shell in a welding or bolt sealing mode.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

1. according to the silencer, the silencing pieces are uniformly arranged in the fixed mounting device, the synchronous driving device is arranged on the outer end face side of the fixed mounting device and penetrates through the outer wall of the fixed mounting device to be connected with the silencing pieces, and the silencing pieces are driven synchronously, so that the insertion loss of the silencer with the compatible silencing performance and aerodynamic performance is adjusted. The larger the rotating angle is, the higher the insertion loss is, the higher the noise reduction amount is, and the problems that the noise reduction requirement cannot be met due to the fact that the air volume of a ventilation system passing through a silencer is increased, the pneumatic noise is increased, and the acoustic performance of the silencer is reduced along with the increase of the service life can be avoided.

2. According to the silencer, one end of the rotating shaft is connected with the synchronous driving device and the silencing sheet, the other end of the rotating shaft is connected with the driving mechanism, the silencing sheet can move synchronously under the driving action of the driving mechanism, the rotation angle of the silencing sheet is convenient to adjust, and the silencing performance and the aerodynamic performance of the silencer with the compatible silencing performance and the aerodynamic performance are improved.

3. According to the silencer, the whole silencer shell is of a rectangular tubular structure, and the three reinforcing plates with the annular pipe walls are arranged on the periphery of the pipe wall of the rectangular tubular structure, so that the strength of the silencer shell is improved, and the safety of the silencer with the compatible silencing performance and aerodynamic performance is improved.

4. According to the silencer, the flange is of a rectangular annular structure as a whole, the flange is fixedly arranged on the silencer shell in a welding mode, the outer end of the rectangular annular structure is provided with the extension table which extends around, and the silencer compatible with the silencing performance and the aerodynamic performance is fixedly arranged between the fan and the ventilation pipeline, so that the whole ventilation system is guaranteed to have good sealing performance.

5. According to the silencer, the tail ends of three short rods of the E-shaped connecting rod mechanism are fixedly connected with the rotating shaft in a bolt fixing mode, so that the silencing sheet can rotate along the central axis, the insertion loss change range of the silencer with the silencing performance and the aerodynamic performance compatible can be adjusted conveniently, preferably, the E-shaped connecting rod mechanism can be adjusted manually or electrically, and during electric adjustment, linkage with a ventilation air-conditioning system can be realized, and dynamic adjustment and control of noise reduction are realized.

6. According to the silencer, the silencing sheets are used for silencing operation of a ventilation system, insertion loss is adjusted by adjusting the distance between the end faces of two adjacent silencing sheets, and the noise reduction operation under different air volumes is realized, so that the silencer compatible with silencing performance and aerodynamic performance has a wider insertion loss variation range. And the insertion loss of the silencer compatible with the silencing performance and the aerodynamic performance is increased along with the increase of the rotation angle, so that the applicable wind speed of the silencer compatible with the silencing performance and the aerodynamic performance is improved, the appearance size of the corresponding silencer compatible with the silencing performance and the aerodynamic performance can be properly reduced, and the spatial arrangement, installation and debugging are facilitated.

Drawings

FIG. 1 is a schematic diagram of a muffler three-dimensional model with an adjustable performance adapted to intake air parameters according to an embodiment of the present invention;

FIG. 2 is a left side view of a muffler with an adjustable performance adapted to intake air parameters according to an embodiment of the present invention;

FIG. 3 is a rear view of a muffler with an adjustable performance adapted to intake air parameters according to an embodiment of the present invention;

FIG. 4 is a schematic view of the section A-A (the silencing sheet is parallel to the air inlet direction) in FIG. 3;

FIG. 5 is a schematic view of section A-A of FIG. 3 (with the silencing tab rotated 45 clockwise);

FIG. 6 is a schematic view of section A-A of FIG. 3 (with the noise canceling sheet rotated 45 counterclockwise);

FIG. 7 is a schematic view of an adjustable muffler driving and locking mechanism according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of an acoustic baffle according to an embodiment of the present invention;

fig. 9 is a schematic sectional view taken along line B-B in fig. 8.

In all the figures, the same reference numerals denote the same features, in particular: 1-flange, 2-silencing sheet, 201-damping net sheet, 202-glass fiber cloth/non-woven fabric, 203-keel, 204-sound absorption material, 205-dome, 3-connecting rod, 4-lock catch, 5-rotating shaft, 6-silencer shell and 7-driving mechanism.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in fig. 1 to 9, the embodiment of the present invention provides a muffler with adjustable performance adapted to intake air parameters, and the muffler with compatible muffling performance and aerodynamic performance includes a fixed mounting device, a synchronous driving device, and a muffling sheet 2. The silencing pieces 2 are uniformly arranged inside the fixed mounting device, the synchronous driving device is arranged on the outer end face side of the fixed mounting device, and penetrates through the outer wall of the fixed mounting device to be connected with the silencing pieces 2 to synchronously drive the silencing pieces 2, so that the insertion loss of the silencer with the compatible silencing performance and aerodynamic performance is adjusted. The larger the rotating angle is, the higher the insertion loss is, the higher the noise reduction amount is, and the problems that the noise reduction requirement cannot be met due to the fact that the air volume of a ventilation system passing through a silencer is increased, the pneumatic noise is increased, and the acoustic performance of the silencer is reduced along with the increase of the service life can be avoided.

As shown in fig. 1, the stationary mounting means comprises a flange 1 and a muffler shell 6. The silencer shell 6 is a main body structure of the fixed installation device, the silencer shell 6 is integrally of a rectangular tubular structure, and three reinforcing plates with annular pipe walls are arranged on the periphery of the pipe wall of the rectangular tubular structure, so that the strength of the silencer shell 6 is improved, and the safety of a silencer with compatible silencing performance and aerodynamic performance is improved. And two opposite surfaces around the silencer shell 6 are symmetrically provided with six circular through holes which are arranged in the middle of the outer wall of the silencer shell 6 in two rows and three in each row and are used for installing the synchronous driving device and the silencing pieces 2. Simultaneously, two pipe orifices departments of 6 rectangle tubular structures of silencer shell are located to flange 1, this flange 1 is whole to be rectangle annular structure, through welded mode with this flange 1 fixed mounting on silencer shell 6, and be equipped with the extension platform that extends all around mutually in the outer end of this rectangle annular structure, a silencer fixed mounting for with compatible noise elimination performance and aerodynamic performance is between fan and air pipe, guarantee whole ventilation system has good leakproofness, improve the reliability and the practicality of this compatible noise elimination performance and aerodynamic performance's silencer.

Further, as shown in fig. 1, 2 and 7, the synchronous drive device includes a link 3, a locker 4, a rotation shaft 5 and a drive mechanism 7. Wherein, the whole cylindrical rod that is of pivot 5, inside muffler shell 6 reserved circular through-hole was located to this cylindrical rod total six its head and the end both ends, guaranteed simultaneously that pivot 5 can be inside around the axis rotation reserving circular through-hole, synchronous drive device and noise elimination piece 2 are connected to this 5 one end of pivot, the other end with actuating mechanism 7 is connected, and noise elimination piece 2 is in can synchronous motion under actuating mechanism 7's the driving action, be convenient for adjust noise elimination piece 2's rotation angle, improve this compatible noise elimination performance and aerodynamic performance's muffler's reliability. The connecting rod 3 and the lock catch 4 jointly form an E-shaped connecting rod mechanism, the synchronous driving device is provided with two E-shaped connecting rod mechanisms, and E-shaped openings of the two E-shaped connecting rod mechanisms face the first end and the last end of the silencer shell 6 respectively, so that the silencing pieces 2 connected with the two E-shaped connecting rod mechanisms can keep different rotation directions. The tail ends of three short rods of the E-shaped connecting rod mechanism are fixedly connected with the rotating shaft 5 in a bolt fixing mode, so that the noise elimination sheet 2 can rotate along the central axis, the insertion loss change range of the noise eliminator with the compatible noise elimination performance and the aerodynamic performance can be adjusted conveniently, preferably, the E-shaped connecting rod mechanism can be adjusted manually or electrically, and during the electrical adjustment, the E-shaped connecting rod mechanism can be linked with a ventilation air-conditioning system, so that the dynamic adjustment and control of noise reduction are realized.

As shown in fig. 1, 4, 5 and 6, the muffler compatible with noise elimination performance and aerodynamic performance is provided with six noise elimination sheets 2, the noise elimination sheets 2 are integrally of a rectangular plate structure with two pairs of semi-cylindrical end surfaces, meanwhile, a cylindrical through hole is arranged at the central axis position of the noise elimination sheets 2 and is used for fixedly mounting a rotating shaft 5 and the noise elimination sheets 2, the noise elimination sheets 2 are used for carrying out noise elimination operation of a ventilation system, and the insertion loss is adjusted by adjusting the distance between the end surfaces of two adjacent noise elimination sheets 2 to realize noise reduction operation under different air volumes, so that the muffler compatible with noise elimination performance and aerodynamic performance has a wider insertion loss variation range, and the practicability and reliability of the muffler compatible with noise elimination performance and aerodynamic performance are improved. And the insertion loss of the silencer compatible with the silencing performance and the aerodynamic performance is increased along with the increase of the rotation angle, so that the applicable wind speed of the silencer compatible with the silencing performance and the aerodynamic performance is improved, the appearance size of the corresponding silencer compatible with the silencing performance and the aerodynamic performance can be properly reduced, and the spatial arrangement, installation and debugging are facilitated.

Fig. 8 and 9 are schematic structural views of the silencing sheet 2 in the embodiment of the invention. The silencing sheet 2 comprises a damping mesh 201, glass fiber cloth/non-woven fabric 202, a keel 203 and a sound absorption material 204 in turn from inside to outside. The main body of the silencing sheet 2 is a rectangular cylinder, the internal material is arranged in a vertically symmetrical structure, two ends of the silencing sheet are provided with air guide hoods 205, and the upper end and the lower end of the silencing sheet are covered by damping meshes 201. The damping mesh 201 is rectangular sheet-shaped, and a plurality of holes are formed on the surface of the damping mesh. Secondly, the damping mesh 201 replaces the traditional mesh punched by a metal or nonmetal hard material, so that the vibration of the damping mesh 201 caused by turbulent airflow entering the silencer can be quickly reduced, and the energy of the turbulent airflow is quickly consumed, thereby reducing secondary sound caused by flow-induced vibration, reducing regenerative noise and improving insertion loss. The regenerative noise is reduced, and the applicable wind speed of the silencer is improved, so that the volume of the silencer is reduced, and the occupied space is reduced. A protective layer made of glass fiber cloth/non-woven fabric 202 is arranged below the damping mesh 201, and meanwhile, the glass fiber cloth/non-woven fabric 202 has excellent heat resistance and moisture resistance, so that long-time operation of the noise reduction sheet is guaranteed. In addition, the glass fiber cloth/non-woven fabric 202 has high tensile strength and good insulating property, and has good protection effect on the internal sound attenuation material 204. The keel 203 is positioned below the protective layer formed by the glass fiber cloth/non-woven fabric 202, and the keel 203 is composed of a plurality of rectangular frames, namely, the keel 204 has a fixing function on the sound absorption material and also has a fixing function on the whole protective module.

Preferably, as shown in fig. 4-6, in the embodiment of the present invention, the silencing sheet 2 can rotate around the rotating shaft 5 in real time by being driven by the driving mechanism 7 according to the serial numbers of the ventilation volume and the flow rate, and the angle between the silencing sheet 2 and the direction of the intake air can be adjusted to be-45 ° - +45 °, so as to adjust the insertion loss of the silencer with the silencing performance and the aerodynamic performance compatible, and the larger the rotation angle is, the higher the insertion loss is, the higher the noise reduction volume is, the silencing performance of the silencer is greatly improved, and meanwhile, the silencer has good aerodynamic performance. Specifically, as shown in fig. 4, according to one embodiment of the present invention, the sound-absorbing sheet 2 is parallel to the direction of the inlet air, that is, the included angle between the sound-absorbing sheet 2 and the direction of the inlet air is 0 °, at this time, the air is guided by the flow-guiding cover 205 of the sound-absorbing sheet 2, the flow direction and the flow velocity of the air are changed, and meanwhile, the air enters through the array holes on the damping mesh 201, and the energy of the air is absorbed by the glass fiber cloth/non-woven fabric 202 and the sound-absorbing material 204, so that the noise energy is greatly reduced. In addition, as shown in fig. 5 and fig. 6, two other embodiments of the present invention are shown, wherein an angle between the silencing sheet 2 and the wind direction of the inlet wind in fig. 5 is 45 ° clockwise, an angle between the silencing sheet 2 and the wind direction of the inlet wind in fig. 6 is 45 ° counterclockwise, and an included angle between the silencing sheet 2 and the wind direction of the inlet wind can be adjusted according to the actual wind volume and flow rate, and the angle adjustment range can reach-45 ° - +45 °. Taking fig. 5 as an example, after the intake air touches the silencing sheet 2, the intake air turns under the guiding effect of the air guide sleeve 205, the flow speed is accelerated, most of the sound wave energy is absorbed by the glass fiber cloth/non-woven fabric 202 and the silencing material 204, the noise reduction effect is further improved, and the air guide sleeve 205 is of an arc-shaped structure and plays a good role in guiding the flow, so that the silencer provided by the embodiment of the invention has good aerodynamic performance.

The embodiment of the invention provides a muffler with adjustable performance and adaptive to air inlet parameters, which has the following working principle and specific implementation steps:

the working principle of the muffler is as follows: during the silencing operation of the ventilation system, the ventilation air-conditioning system can be linked through manual or electric adjustment and during electric adjustment, and the noise reduction amount can be dynamically adjusted and controlled. Form E type link mechanism drive pivot 5 through drive connecting rod 3 and hasp 4 jointly and take place to rotate, further drive noise reduction piece 2 takes place to rotate, the change of noise reduction piece 2's angle and changes, the pivoted angle is big more, insertion loss is high more, it is high more to fall the noise level, can avoid ventilation system through the increase of the amount of wind of silencer, pneumatic noise increase and along with the increase of service life silencer acoustic performance decline lead to can not satisfy the demand of making an uproar of falling.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.