Noise reduction device and range hood comprising same

Abstract

The invention discloses a noise reduction device and a range hood comprising the same, the noise reduction device is used for noise reduction of a fan system, the noise reduction device comprises a noise concentrator, the noise concentrator is arranged in the fan system, the fan system comprises a volute, the noise concentrator is arranged corresponding to the volute, and the noise concentrator is arranged in the volute. A noise concentrator is arranged in the volute, an air inlet area is formed between the noise concentrator and the volute, the noise concentrator is arranged in the height direction of the fan system, the noise concentrator is provided with a reflecting surface facing the air inlet area, and the noise concentrator concentrates noise of the volute through the reflecting surface; and the noise reduction part is arranged in the air inlet area and is far away from an air inlet of the fan system, and the noise reduction part is used for absorbing noise from the reflecting surface. The noise reduction part is arranged in the air inlet area so as to intensively collect noise from different directions, so that the noise reduction part can be arranged at a specific position, the space in the air inlet area is reasonably utilized, the noise reduction effect is improved, and meanwhile it is guaranteed that the working efficiency of the fan system is not affected.

Description

Technical Field

[0001] The present invention relates to the technical field of fan systems, and in particular to a noise reduction device and a range hood comprising the same. Background Art

[0002] The noise energy distribution inside the range hood is uneven, and the internal sound field energy is relatively dispersed, so it is impossible to concentrate it in one place for sound absorption treatment. It often requires a relatively large area of ​​sound-absorbing cotton to be wrapped. This results in a larger sound absorption area, higher costs, and some sound-absorbing cotton positions will affect the outflow space, causing greater resistance to the range hood fluid, resulting in greater fluid noise. At this time, noise reduction is not worth the loss.

[0003] In addition, the sound absorption coefficient curve of porous materials such as sound-absorbing cotton is that as the thickness of the sound-absorbing cotton increases, the low-frequency sound absorption coefficient is better. However, due to the limited internal space of the range hood, thicker sound-absorbing cotton cannot be arranged, especially in the fan system with high noise. Due to space limitations, thicker sound-absorbing cotton cannot be set in the air inlet area, resulting in high noise and affecting the user experience. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defect of the prior art that it is difficult to reduce noise due to space limitations, and to provide a noise reduction device and a range hood comprising the same.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] A noise reduction device, the noise reduction device is used for reducing noise in a fan system, the noise reduction device comprises:

[0007] A noise concentrator, wherein the noise concentrator is arranged in the fan system, the fan system includes a volute, the noise concentrator is arranged corresponding to the volute, and an air inlet area is formed between the noise concentrator and the volute, the noise concentrator is arranged along the height direction of the fan system, and the noise concentrator is provided with a reflection surface toward the air inlet area, and the noise concentrator concentrates the noise of the volute through the reflection surface;

[0008] A noise reduction unit is arranged in the air inlet area and away from the air inlet of the fan system, and is used to absorb noise from the reflecting surface.

[0009] In the present solution, a noise concentrator is provided to collect the noise generated by the volute and the noise from different directions in the fan system, thereby preventing noise dispersion and arranging noise reduction structures from different directions and positions. The concentrated noise is reflected to the noise reduction part through the reflection surface, so that the noise reduction part can be set at a specific position, which is the side wall of the fan system away from the air inlet, so that the noise reduction part can reasonably utilize the space in the air inlet area, and avoid the scattered noise reduction parts from generating resistance to the airflow in the air inlet area. The noise reduction part arranged on the side wall of the fan system away from the air inlet can be correspondingly increased in thickness to improve the noise reduction effect while ensuring that the working efficiency of the fan system is not affected.

[0010] Preferably, the noise concentrator further includes a first driving unit, which is disposed in the noise concentrator, one end of which is connected to the reflecting surface, and the first driving unit is used to drive the reflecting surface to move closer to or away from the air inlet area.

[0011] In this solution, the above-mentioned setting is used to realize the movement of the reflecting surface, thereby effectively concentrating and reflecting the noise.

[0012] Preferably, along the height direction of the fan system, one end of the reflecting surface away from the noise reduction part is hinged to the shell of the noise concentrator, and one end of the reflecting surface close to the noise reduction part approaches or moves away from the air inlet area through the first driving part.

[0013] In the present solution, through the above-mentioned setting, it is possible to achieve that the reflecting surface forms an angle with the shell when it moves, and then the noise is concentrated and reflected to the side wall of the fan system away from the air inlet, that is, the position of the noise reduction part, thereby realizing the specific position setting of the noise reduction part, eliminating the need to disperse the noise reduction parts, saving space, and reducing the resistance to the airflow flow in the air inlet area.

[0014] Preferably, the noise reduction portion includes a noise reduction surface, the noise reduction surface is arranged corresponding to the reflection surface, and the noise reduction portion also includes a second driving portion, and the second driving portion is used to drive the noise reduction surface to approach or move away from the reflection surface.

[0015] In this solution, the above settings are used to realize the movement of the noise reduction surface. When the noise reduction surface moves, it keeps corresponding to the moving reflective surface to prevent the noise reflected after concentration from not being received by the noise reduction surface.

[0016] Preferably, along the height direction of the fan system, one end of the noise reduction surface away from the noise concentrator is hinged to the shell of the noise reduction part, and one end of the noise reduction surface close to the noise concentrator approaches or moves away from the reflecting surface through the second driving part.

[0017] In this solution, through the above arrangement, when the noise reduction surface moves, it corresponds to the moving reflective surface.

[0018] Preferably, when the impeller speed of the fan system is 500-800r, the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 0-2°;

[0019] When the impeller speed of the fan system is 800-1200r, the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 2-5°;

[0020] When the impeller speed of the fan system is 1200-1600r, the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 5-10°.

[0021] In this solution, through the above-mentioned setting, the angle of the reflection surface is adjusted according to the different noise intensities generated at different impeller rotation speeds, thereby effectively concentrating and reflecting the noise, and eliminating the noise through the noise reduction surface.

[0022] Preferably, when the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 0-2°, the angle between the noise reduction surface and the side wall of the fan system away from the air inlet is 90-92°;

[0023] When the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 2-5°, the angle between the noise reduction surface and the side wall of the fan system away from the air inlet is 92-95°;

[0024] When the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 5-10°, the angle between the noise reduction surface and the side wall of the fan system away from the air inlet is 95-100°.

[0025] In this solution, through the above-mentioned settings, the angle of the noise reduction surface is adjusted according to the change in the angle of the reflecting surface at different impeller rotation speeds, thereby effectively receiving the noise from the reflecting surface and eliminating the noise.

[0026] Preferably, the noise reduction surface is evenly covered with sound-absorbing cotton.

[0027] In this solution, the above-mentioned setting is used to effectively absorb and eliminate noise.

[0028] Preferably, the thickness of the sound-absorbing cotton is 30-230 mm.

[0029] In this solution, by setting the noise reduction part on the side wall of the fan system away from the air inlet, there is no need to worry about the noise reduction part causing resistance to the airflow. At this time, the appropriate thickness of the sound-absorbing cotton can be selected according to the noise intensity, and there is no need to worry about the sound-absorbing cotton being too thick and occupying the flow space of the airflow in the air inlet area.

[0030] A range hood comprises the noise reduction device as described above.

[0031] In this solution, the range hood includes the above-mentioned noise reduction device to reduce the noise reduction cost while ensuring that the working efficiency of the fan system is not affected, effectively concentrate the noise and eliminate it, the noise reduction effect is better and will not occupy the remaining space in the fan system.

[0032] The positive progressive effect of the present invention is that the present invention arranges a noise concentrator to collect the noise generated by the volute and the noise from different directions in the fan system, prevents the noise from being dispersed and arranges the noise reduction structure from different directions and positions. The concentrated noise is reflected to the noise reduction part through the reflection surface, so that the noise reduction part can be set at a specific position, which is the side wall of the fan system away from the air inlet, so that the noise reduction part can reasonably utilize the space in the air inlet area, avoids the scattered arrangement of the noise reduction part to generate resistance to the airflow in the air inlet area, and the noise reduction part arranged on the side wall of the fan system away from the air inlet can increase the thickness accordingly, so as to improve the noise reduction effect while ensuring that the working efficiency of the fan system is not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The figure is a three-dimensional diagram of a range hood according to a preferred embodiment of the present invention.

[0034] Figure 2 FIG. 1 is a diagram showing the positional relationship between a noise concentrator and a noise reduction unit according to a preferred embodiment of the present invention.

[0035] Figure 3 The figure is a schematic diagram of the reflective surface structure of a preferred embodiment of the present invention.

[0036] Figure 4 Schematic diagram of the noise reduction surface structure of a preferred embodiment of the present invention.

[0037] Figure 5 It is a schematic structural diagram of the second driving part of a preferred embodiment of the present invention.

[0038] Figure 6 It is a schematic structural diagram of the first driving part of a preferred embodiment of the present invention.

[0039] Figure 7 This is a schematic diagram of the angle between the reflective surface and the noise reduction surface when the impeller speed is 500-800r in a preferred embodiment of the present invention.

[0040] Figure 8 This is a schematic diagram of the angle between the reflective surface and the noise reduction surface when the impeller speed is 800-1200r in a preferred embodiment of the present invention.

[0041] Fig. 9Schematic diagram of the angle between the reflective surface and the noise reduction surface when the impeller speed is 1200-1600r in a preferred embodiment of the present invention.

[0042] Description of reference numerals:

[0043] Fan system 100

[0044] Volute 101

[0045] Air intake area 102

[0046] Air inlet 103

[0047] Noise Concentrator 1

[0048] Reflective surface 11

[0049] The first driving unit 12

[0050] Worm 121

[0051] Motor 122

[0052] Gear 123

[0053] Housing 13

[0054] Noise reduction unit 2

[0055] Noise Reduction Surface 21

[0056] The second driving unit 22

[0057] Drive motor 221

[0058] Joystick 222

[0059] Shell 23 DETAILED DESCRIPTION

[0060] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0061] This embodiment provides a noise reduction device, the specific structure is as follows Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the noise reduction device is used for noise reduction of the fan system 100, and the noise reduction device includes:

[0062] A noise concentrator 1 is disposed in a fan system 100. The fan system 100 includes a volute 101. The noise concentrator 1 is disposed corresponding to the volute 101, and an air inlet area 102 is formed between the noise concentrator 1 and the volute 101. The noise concentrator 1 is disposed along the height direction of the fan system 100, and a reflection surface 11 is disposed on the noise concentrator 1 toward the air inlet area 102. The noise concentrator 1 concentrates the noise of the volute 101 through the reflection surface 11.

[0063] The noise reduction part 2 is arranged in the air inlet area 102 and away from the air inlet 103 of the fan system 100 . The noise reduction part 2 is used to absorb the noise from the reflection surface 11 .

[0064] Specifically, along the height direction of the fan system 100, the air inlet 103 is located below the volute 101 and is connected to the air inlet area 102. The noise concentrator 1 is arranged in the fan system 100 and is located on the side wall of the fan system 100 away from the volute 101. The noise concentrator 1 extends along the height direction of the fan system 100. The noise concentrator 1 is arranged corresponding to the volute 101, and the air inlet area 102 is between the noise concentrator 1 and the volute 101. The noise concentrator 1 is provided with a reflection surface 11 corresponding to the air inlet area 102. The reflection surface 11 has a flat surface and is made of a material used for reflecting noise in the prior art, such as stainless steel or other metal materials used for reflecting noise. By setting the noise concentrator 1, the noise generated by the volute 101 and the noise from different directions in the fan system 100 are collected and reflected along the direction of the reflection surface 11 to prevent the noise from spreading in unexpected directions.

[0065] In addition, in this embodiment, a noise reduction unit 2 is also provided, and the noise reduction unit 2 is located above the noise concentrator 1 along the height direction of the fan system 100, and the noise reduction unit 2 is connected to the side wall of the fan system 100 away from the air inlet 103. The noise concentrator 1 reflects the concentrated noise to the noise reduction unit 2 through the reflection surface 11, so that the originally scattered noise is concentrated and propagated along the reflection direction, and finally absorbed and reduced by the noise reduction unit 2. Accordingly, the propagation of noise along the reflection direction allows the noise reduction unit 2 to be set at a specific position, which is the side wall of the fan system 100 away from the air inlet 103, so that the noise reduction unit 2 can reasonably use the space in the air inlet area 102, and there is no need to arrange noise reduction structures from different directions and different positions, so as to avoid the noise reduction unit 2 being dispersed and generating resistance to the airflow in the air inlet area 102. The noise reduction unit 2 arranged on the side wall of the fan system 100 away from the air inlet 103 can be increased in thickness accordingly, so as to improve the noise reduction effect while ensuring that the working efficiency of the fan system 100 is not affected.

[0066] like Figure 6As shown, in this embodiment, the noise concentrator 1 also includes a first driving unit 12, which is disposed in the noise concentrator 1, and one end of the first driving unit 12 is connected to the reflecting surface 11, and the first driving unit 12 is used to drive the reflecting surface 11 to approach or move away from the air inlet area 102.

[0067] Specifically, the first driving unit 12 includes a worm 121, a motor 122 and a gear 123. The noise concentrator 1 also includes a housing 13. The reflective surface 11 is a surface of the housing 13 facing the air inlet area 102. The reflective surface 11 can move relative to the housing 13. The first driving unit 12 is arranged in the housing 13, wherein the worm 121 extends along the thickness direction of the housing 13, one end of the worm 121 abuts against the surface of the reflective surface 11 away from the air inlet area 102, and the other end of the worm 121 is sleeved with a gear 123. The gear 123 is used to mesh with the output shaft of the motor 122, so as to drive the reflective surface 11 abutting against the worm 121 to approach or move away from the air inlet area 102 when the motor 122 is turned on. The first driving unit 12 can be electrically connected to the control panel of the fan system 100 to drive the reflective surface 11 to move in real time. This is a prior art and will not be described in detail here.

[0068] Furthermore, in this embodiment, along the height direction of the fan system 100, the end of the reflecting surface 11 away from the noise reduction part 2 is hinged to the shell 13 of the noise concentrator 1, and the end of the reflecting surface 11 close to the noise reduction part 2 is close to or away from the air inlet area 102 through the first driving part 12.

[0069] Specifically, the noise concentrator 1 is arranged along the height direction of the fan system 100, the reflecting surface 11 also extends along the height direction of the fan system 100, the noise reduction part 2 is located above the noise concentrator 1, and the end of the reflecting surface 11 close to the noise reduction part 2 is movably connected to the shell 13, that is, the size of the end of the reflecting surface 11 close to the noise reduction part 2 is smaller than the size of the shell 13, so that the reflecting surface 11 can be embedded in the shell 13 when the reflecting surface 11 moves, and the end of the reflecting surface 11 away from the noise reduction part 2 is hinged to the shell 13 through a rotating shaft, so that the part of the reflecting surface 11 close to the middle area of ​​the volute 101 can move accordingly, so as to specifically reflect the noise from the volute 101. When the reflecting surface 11 moves, it is realized that it forms an angle with the shell 13, and then the noise is concentrated and reflected to the side wall of the fan system 100 away from the air inlet 103, that is, the position of the noise reduction part 2, so that the noise reduction part 2 is set at a specific position, and there is no need to disperse the noise reduction part 2, which saves space and reduces the resistance to the airflow in the air inlet area 102.

[0070] In order to prevent the first driving unit 12 from driving the reflecting surface 11 to move and then being unable to reset, the present embodiment is further provided with an elastic member (not shown in the figure), which is a spring in the prior art, one end of which is connected to the surface of the reflecting surface 11 away from the air inlet area 102, and the other end of which is connected to the housing 13. By providing the elastic member, the reflecting surface 11 can be reset by providing elastic force through the elastic member after the reflecting surface 11 moves. Preferably, the travel of the elastic member is 2-20 mm.

[0071] like Figure 4 and Figure 5 As shown, in this embodiment, the noise reduction part 2 includes a noise reduction surface 21, and the noise reduction surface 21 is arranged corresponding to the reflection surface 11. The noise reduction part 2 also includes a second driving part 22, and the second driving part 22 is used to drive the noise reduction surface 21 to approach or move away from the reflection surface 11.

[0072] Specifically, the noise reduction part 2 is a parallelogram in cross section, wherein the noise reduction surface 21 is arranged on the side of the noise reduction part 2 facing the noise concentrator 1, and a second driving part 22 is arranged on the side of the noise reduction part 2 away from the noise concentrator 1, the second driving part 22 includes a driving motor 221 and a rocker 222, the driving motor 221 and the rocker 222 are arranged on the side of the noise reduction part 2 away from the noise concentrator 1, the noise reduction part 2 also includes a shell 23, the shell 23 includes two side walls arranged in parallel, the two side walls arranged in parallel are located between the noise reduction surface 21 and the side of the noise reduction part 2 away from the noise concentrator 1, the two side walls arranged in parallel are respectively hinged to the noise reduction surface 21 and the side surface of the noise reduction part 2 away from the noise concentrator 1 through a rotating shaft, when the driving motor 221 is turned on, the rocker 222 is driven to swing, thereby making the noise reduction surface 21 approach or move away from the reflecting surface 11. It can be understood that when the noise reduction surface 21 moves, it keeps corresponding to the moving reflective surface 11 to prevent the noise reflected after concentration from not being received by the noise reduction surface 21 .

[0073] In this embodiment, along the height direction of the fan system 100, the end of the noise reduction surface 21 away from the noise concentrator 1 is hinged to the shell 23 of the noise reduction part 2, and the end of the noise reduction surface 21 close to the noise concentrator 1 approaches or moves away from the reflecting surface 11 through the second driving part 22.

[0074] Specifically, the housing 23 includes two parallel side walls, one of which is connected to the side wall of the fan system 100 away from the air inlet 103, and the other side wall is arranged near the noise concentrator 1. Both side walls are hinged to the noise reduction surface 21. When the second driving unit 22 is turned on, since the parallel side wall is connected to the side wall of the fan system 100 away from the air inlet 103, the other side wall moves under the action of the rocker 222. Accordingly, the noise reduction surface 21 rotates with the end of the noise reduction surface 21 away from the noise concentrator 1 as the axis under the action of the other side wall to achieve approaching or moving away from the reflective surface 11. The second driving unit 22 can be electrically connected to the control panel of the fan system 100 to drive the noise reduction surface 21 to move in real time. This is a prior art and will not be described in detail here.

[0075] like Figure 7 , Figure 8 and Fig. 9 As shown, in this embodiment, when the impeller speed of the fan system 100 is 500-800r, the angle between the reflection surface 11 and the side wall of the housing 13 away from the air inlet area 102 is 0-2°;

[0076] When the impeller speed of the fan system 100 is 800-1200r, the angle between the reflection surface 11 and the side wall of the housing 13 away from the air inlet area 102 is 2-5°;

[0077] When the impeller speed of the fan system 100 is 1200-1600r, the angle between the reflection surface 11 and the side wall of the housing 13 away from the air inlet area 102 is 5-10°.

[0078] Specifically, when the impeller speed of the fan system 100 is 500-800r, the gear of the fan system 100 is weak, the airflow velocity is slow, the noise generated by the impeller is small, and the angle α between the reflective surface 11 and the side wall of the shell 13 away from the air inlet area 102 is preferably 2°, so as to concentrate and specifically reflect the noise to the noise reduction part 2. When the impeller speed of the fan system 100 is 800-1200r, the gear of the fan system 100 is strong, and the angle α between the reflective surface 11 and the side wall of the shell 13 away from the air inlet area 102 is preferably 5°, so as to concentrate and specifically reflect the noise to the noise reduction part 2. When the impeller speed of the fan system 100 is 1200-1600r, the gear of the fan system 100 is the instantaneous suction gear, the airflow velocity is fast, the noise generated by the impeller is large, and the angle α between the reflective surface 11 and the side wall of the housing 13 away from the air inlet area 102 is preferably 10°. The first driving part 12 is provided to adjust the angle of the reflective surface 11 according to the different noise intensities generated at different impeller speeds, thereby effectively concentrating and reflecting the noise, and eliminating the noise through the noise reduction surface 21.

[0079] Further, when the angle between the reflective surface 11 and the side wall of the housing 13 away from the air inlet area 102 is 0-2°, the angle between the noise reduction surface 21 and the side wall of the fan system 100 away from the air inlet 103 is 90-92°;

[0080] When the angle between the reflection surface 11 and the side wall of the housing 13 away from the air inlet area 102 is 2-5°, the angle between the noise reduction surface 21 and the side wall of the fan system 100 away from the air inlet 103 is 92-95°;

[0081] When the angle between the reflective surface 11 and the side wall of the housing 13 away from the air inlet area 102 is 5-10°, the angle between the noise reduction surface 21 and the side wall of the fan system 100 away from the air inlet 103 is 95-100°.

[0082] Specifically, when the angle α between the reflecting surface 11 and the side wall of the shell 13 away from the air inlet area 102 is preferably 2°, the angle β between the noise reduction surface 21 and the side wall of the fan system 100 away from the air inlet 103 is preferably 92°. When the angle α between the reflecting surface 11 and the side wall of the shell 13 away from the air inlet area 102 is preferably 5°, the angle β between the noise reduction surface 21 and the side wall of the fan system 100 away from the air inlet 103 is preferably 95°. When the angle α between the reflecting surface 11 and the side wall of the shell 13 away from the air inlet area 102 is preferably 10°, the angle β between the noise reduction surface 21 and the side wall of the fan system 100 away from the air inlet 103 is preferably 100°. At different impeller speeds, the angle of the noise reduction surface 21 is adjusted according to the angle change of the reflecting surface 11, thereby effectively receiving the noise from the reflecting surface 11 and eliminating the noise.

[0083] In this embodiment, the noise reduction surface 21 is evenly distributed with sound-absorbing cotton. Sound-absorbing cotton is a structure used in the prior art to absorb and eliminate noise. The noise reduction surface 21 is evenly distributed with sound-absorbing cotton to concentrate and reflect the noise in the fan system 100 through the movable noise reduction surface 21 and the movable reflection surface 11, and absorb it in a targeted manner, so that the sound-absorbing cotton does not need to be dispersedly arranged at various positions in the fan system 100, avoiding the airflow resistance caused by the dispersed arrangement, affecting the working efficiency of the fan system 100, and avoiding the high cost and low noise reduction effect caused by the dispersed arrangement, so as to effectively absorb and eliminate the noise.

[0084] In this embodiment, the thickness of the sound-absorbing cotton is 30-230mm. Specifically, according to the sound absorption coefficient test in the prior art, the sound-absorbing cotton has a better sound absorption effect on low-frequency noise as the thickness increases, and through testing the sound-absorbing cottons with thicknesses of 30mm, 80mm, 130mm, 180mm and 230mm, it is found that on the basis of cost saving, the sound absorption effect of the sound-absorbing cotton with a thickness of 130mm on low-frequency noise can meet the noise reduction requirements, and the sound absorption effect of the sound-absorbing cotton with a thickness greater than 130mm and the sound-absorbing cotton with a thickness of 130mm on low-frequency noise is slightly different, but the cost is higher, therefore, the thickness of the sound-absorbing cotton is preferably 130mm.

[0085] In addition, it can be understood that in this embodiment, by setting the noise reduction part 2 on the side wall of the fan system 100 away from the air inlet 103, there is no need to worry that the noise reduction part 2 will generate resistance to the airflow. At this time, a suitable thickness of the sound-absorbing cotton can be selected according to the noise intensity, and there is no need to worry about the sound-absorbing cotton being too thick and occupying the flow space of the airflow in the air inlet area 102.

[0086] The present embodiment also provides a range hood, which includes the above-mentioned noise reduction device to reduce the noise reduction cost, effectively concentrate and eliminate the noise while ensuring that the working efficiency of the fan system 100 is not affected, and the noise reduction effect is better without occupying the remaining space in the fan system 100.

[0087] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A noise reduction device, which is used for reducing noise in a fan system, characterized in that: The noise reduction device comprises: A noise concentrator, wherein the noise concentrator is arranged in the fan system, the fan system includes a volute, the noise concentrator is arranged corresponding to the volute, and an air inlet area is formed between the noise concentrator and the volute, the noise concentrator is arranged along the height direction of the fan system, and the noise concentrator is provided with a reflection surface toward the air inlet area, and the noise concentrator concentrates the noise of the volute through the reflection surface; A noise reduction unit is arranged in the air inlet area and away from the air inlet of the fan system, and is used to absorb noise from the reflecting surface.

2. The noise reduction device according to claim 1, characterized in that: The noise concentrator further includes a first driving unit, which is disposed in the noise concentrator. One end of the first driving unit is connected to the reflecting surface, and the first driving unit is used to drive the reflecting surface to approach or move away from the air inlet area.

3. The noise reduction device according to claim 2, characterized in that: Along the height direction of the fan system, one end of the reflecting surface away from the noise reduction part is hinged to the shell of the noise concentrator, and one end of the reflecting surface close to the noise reduction part approaches or moves away from the air inlet area through the first driving part.

4. The noise reduction device according to claim 3, characterized in that: The noise reduction part includes a noise reduction surface, and the noise reduction surface is arranged corresponding to the reflection surface. The noise reduction part also includes a second driving part, and the second driving part is used to drive the noise reduction surface to approach or move away from the reflection surface.

5. The noise reduction device according to claim 4, characterized in that: Along the height direction of the fan system, one end of the noise reduction surface away from the noise concentrator is hinged to the shell of the noise reduction part, and one end of the noise reduction surface close to the noise concentrator approaches or moves away from the reflecting surface through the second driving part.

6. The noise reduction device according to claim 5, characterized in that: When the impeller speed of the fan system is 500-800r, the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 0-2°; When the impeller speed of the fan system is 800-1200r, the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 2-5°; When the impeller speed of the fan system is 1200-1600r, the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 5-10°.

7. The noise reduction device according to claim 6, characterized in that: When the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 0-2°, the angle between the noise reduction surface and the side wall of the fan system away from the air inlet is 90-92°; When the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 2-5°, the angle between the noise reduction surface and the side wall of the fan system away from the air inlet is 92-95°; When the angle between the reflecting surface and the side wall of the shell away from the air inlet area is 5-10°, the angle between the noise reduction surface and the side wall of the fan system away from the air inlet is 95-100°.

8. The noise reduction device according to claim 4, characterized in that: The noise reduction surface is evenly covered with sound-absorbing cotton.

9. The noise reduction device according to claim 8, characterized in that: The thickness of the sound-absorbing cotton is 30-230 mm.

10. A range hood, characterized in that: The range hood comprises a noise reduction device as claimed in any one of claims 1 to 9.

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