Sound acquisition device for oil smoke suction device and range hood

Abstract

The sound collection device is arranged in an air duct of the oil smoke suction device and comprises a sound collection element and a shell, a sound transmission channel is defined on the shell and comprises a first channel section and a second channel section which are sequentially connected, and the first channel section and the second channel section are communicated with each other. The sound collecting element is located in the first channel section, the first channel section is provided with a first sound inlet communicated with the second channel section, the second channel section is arranged in the extending direction of the air channel, and a second sound inlet allowing sound in the air channel to enter the second channel section is formed in the leeward end of the shell. The extension line of the opening direction of the first sound inlet intersects with the extension line of the opening direction of the second sound inlet. The sound acquisition device has the advantages that the sound acquisition device not only can realize an oil-proof purpose, but also can fully acquire low-frequency noise signals, so that the accuracy of sound acquisition is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of range hoods, in particular to a sound collection device for a fume extraction device and a range hood. Background Technique

[0002] A range hood is a kitchen appliance for purifying the kitchen environment. The noise of the range hood has always been one of the main problems troubling users. As a new noise reduction technology, active noise reduction is also considered to be applied to the range hood for noise reduction. The active noise reduction device usually includes a microphone and a speaker, that is, the microphone collects the noise generated when the range hood is working, and the collected noise sound wave is transmitted to the controller in the form of an electrical signal. After being analyzed and processed by the controller, an instruction is sent to the speaker to control the speaker to emit a sound wave matching the noise sound wave to neutralize the noise sound wave, so as to achieve the noise reduction effect. For example, the Chinese invention patent application with the application number CN202010935185.0 (the application publication number is: CN111928310A) discloses such a range hood with an active noise reduction function. The microphone of this range hood is arranged in the housing and surrounds the blower in an array distribution manner, and the speaker assembly is distributed below the blower. Another example is the "Range Hood and Its Active Noise Reduction Device" with the application number CN202221822214.3 and the "Low-Noise Range Hood" with the application number CN202222650354.3, which also have similar disclosures.

[0003] In order to ensure the noise reduction effect, in the prior art, the microphones and speakers used in the active noise reduction system are often arranged in the internal air duct of the range hood. However, due to the oily environment of the range hood, the microphones and speakers are often contaminated, resulting in a reduction in the noise reduction effect of the active noise reduction system over time and even malfunction. Therefore, the Chinese utility model patent application with the application number CN201820250745.7 discloses an active noise reduction device for a range hood with an oil prevention device, which includes an incoming device, a central data processor, and a noise reduction unit. The incoming device includes a microphone, which is arbitrarily installed at a location on the range hood. The noise reduction unit includes at least two noise reduction boxes, which are arranged at the bottom of the volute of the range hood, facing the air inlet. An oil prevention device is provided below the noise reduction box, and the oil prevention device is also arranged at the bottom of the volute and covers the noise reduction box. The oil prevention device includes a porous sound-permeable shell and an oil-proof sound-permeable film attached to the surface of the porous sound-permeable shell. At least one noise reduction speaker is provided in the noise reduction box, and both the microphone and the noise reduction speaker are connected to the central data processor. The central data processor loads a self-check module and an oil pollution detection module for the noise reduction device. The oil pollution detection module detects the oil pollution and damage condition of the oil prevention device, and the self-check module receives and processes the self-system signals reported by the device to determine whether there is an increase in the microphone and the noise reduction speaker. At the same time, a timing detection module is provided in the self-check module. However, the oil prevention device of the active noise reduction device in this patent application still has certain deficiencies. The oil prevention device realizes sound transmission and oil prevention through the porous sound-permeable shell and the oil-proof film attached to the surface of the porous sound-permeable shell, without considering the influence of wind noise in the air duct of the range hood, that is, no effective wind noise prevention treatment is carried out. On the other hand, for the above-mentioned porous sound-permeable shell, if the number of openings is large, it will have an adverse impact on oil prevention and wind prevention. If the number of openings is small, more noise will be lost during the propagation process, resulting in a reduction in the accuracy of sound collection.

[0004] For another example, a Chinese invention patent application with the application number CN202210185663.X (publication number: CN114648973A) discloses an active noise reduction device, a range hood, and an active noise reduction method. The active noise reduction device includes a sound signal acquisition device, a processor, a sound signal transmission device, a first housing, and a second housing. The processor is respectively connected to the sound signal acquisition device and the sound signal transmission device. Each housing forms a cavity. The first end of each cavity is open, and the second end of the cavity is closed. The sound signal acquisition device and the sound signal transmission device are respectively located in the corresponding cavities, and the openings of the two cavities are arranged back to back. When the fluid enters any one of the cavities through the opening of any one of the above cavities, an air pressure mass is formed in the any one of the cavities. The air pressure mass located in the cavity cannot continue to be discharged from its closed second end, preventing the subsequent fluid from continuing to flow into the cavity through the cavity opening, achieving the protection of the sound signal acquisition device or the sound signal transmission device in each cavity, and avoiding the pollution and adverse effects of oil fume or water vapor on the devices in the cavity.

[0005] For another example, a Chinese invention patent application with the application number CN202111048335.7 (publication number CN113739232A) discloses a protection device, a range hood, and a control method for the range hood. The protection device includes: a connecting pipe adapted to be installed in the housing of the range hood, the connecting pipe having a first end and a second end; a first housing provided at the second end, the first housing being adapted for sound to pass through and not for oil fume to pass through; a second housing provided at the first end, the second housing being adapted to install an active noise reduction device inside, and the second housing being in internal communication with the connecting pipe. The sound generated during the operation of the range hood will pass through the first housing and enter the connecting pipe, and then enter the active noise reduction device. The active noise reduction device operates to reduce noise. The oil fume generated during the operation of the range hood cannot pass through the first housing and cannot pollute the active noise reduction device.

[0006] As can be seen from the above, for the sound collection devices in the prior art, the internally formed sound propagation channels are divided into two cases: one is like the prior art CN114648973A, where the sound propagation channel does not turn. This form is not conducive to weakening high-frequency sounds, unable to improve the collection accuracy of low-frequency sounds, and the sound collection element is easily contaminated by oil stains. The other is like the prior art CN113739232A, where the sound propagation channel turns, which is conducive to low-frequency sound collection. However, due to two turns, the sound pressure loss in the propagation path is large, affecting the accuracy of sound collection. The sound collection device with multiple turns also makes its volume relatively large, affecting the stability of the air flow at the installation position of the sound collection device. In particular, secondary noise (wind noise) will be generated due to air flow disturbance, further reducing the accuracy of sound collection. Most importantly, the existing sound collection devices basically only perform anti-oil stain treatment and do not consider the influence of wind noise in the air duct of the range hood, that is, no effective anti-wind noise treatment is carried out. In particular, the setting of the connecting pipe in the above-mentioned prior art CN113739232A will occupy a large space in the air duct, and the air flow in the air duct will generate significant wind noise at the connecting pipe. The wind noise will pass through the connecting pipe and enter the position where the microphone is located, causing a great impact on the accuracy of the microphone to collect the target noise. Utility Model Content

[0007] The first technical problem to be solved by the present utility model is, in view of the current situation of the prior art, to provide a sound collection device for a range hood that can not only achieve the purpose of anti-oil, but also enable the target noise signal to be fully collected, thereby ensuring the accuracy of sound collection.

[0008] The second technical problem to be solved by the present utility model is, in view of the current situation of the prior art, to provide a range hood applying the above-mentioned sound collection device.

[0009] The technical solution adopted by the present utility model to solve the first technical problem is: A sound collection device for a range hood is provided in the air duct of the range hood, including a sound collection element, and further including a housing. A sound propagation channel is defined on the housing. The sound propagation channel includes a first channel section and a second channel section connected in sequence. The sound collection element is located in the first channel section. The first channel section has a first sound inlet communicating with the second channel section. The second channel section is arranged along the extension direction of the air duct, and a second sound inlet for the sound in the air duct to enter the second channel section is formed at the windward end of the housing. The extension line of the opening direction of the first sound inlet intersects with the extension line of the opening direction of the second sound inlet.

[0010] The above-mentioned "air duct" can be understood as any section of the flow path from the air inlet of the smoke hood of the self-suction range hood (which can be a range hood or an integrated stove) to the location of the fan system. For example, it can refer to the inner cavity space of the smoke hood, or it can refer to the space in the fan frame where the fan system is located, or it can refer to the channel structure between the fan system and the air outlet of the smoke hood.

[0011] The above-mentioned "the second channel section is arranged along the extension direction of the air duct" can be understood as the overall extension direction of the second channel section is consistent with or parallel to the extension direction of the air duct, and can also be understood as the overall extension direction of the second channel section has a slight inclination angle relative to the extension direction of the air duct.

[0012] The extension line of the first sound inlet opening direction of the first channel section on the shell intersects with the extension line of the second sound inlet opening direction of the second channel section, which can avoid multiple turns as much as possible. On the one hand, it reduces the sound pressure loss on the sound propagation path and improves the accuracy of sound collection. On the other hand, it also makes the volume of the sound collection device as small as possible, avoiding adverse effects on the stability of the airflow flow at the installation position of the sound collection device, reducing the generation of secondary noise (wind noise), and further improving the accuracy of sound collection. The above-mentioned turning path design has a weakening effect on high-frequency sounds (such as non-target noise such as the high-frequency sound part of wind noise and the high-frequency sound components generated by the fan system), but has less effect on low-frequency sounds. Therefore, it can be well applied to the propagation of low-frequency noise in the collection device, which is conducive to the accurate collection of it by the sound collection element.

[0013] Considering that a sound propagation channel of sufficient length needs to be set on the sound propagation path to prevent wind noise in order to reduce the impact of the airflow in the duct on sound collection, the second channel section is arranged in the extension direction of the duct, so that the size of the entire collection device in the direction perpendicular to the extension direction of the duct can be made smaller, that is, the space occupied in the duct of the range hood is smaller, and the wind resistance at the location of the collection device in the duct is smaller, so that it will not affect the stability of the airflow in the duct, and at the same time, it also reduces the generation of wind noise to a certain extent. The above-mentioned "end of the shell facing away from the wind" can be understood as: along the extension direction of the duct, the end of the shell adjacent to the fan system.

[0014] As an improvement, the extension line of the first channel section intersects with the extension line of the second channel section. The extension line of the first channel section can be understood as the line between the location of the sound inlet of the channel section and the location of the sound collecting element, and the extension line of the second channel section can be understood as the line between the location of the sound inlet of the channel section and the location of the sound outlet. In order to further avoid excessive sound loss due to too many turns in the propagation channel, the first channel section and the second channel section are straight channels.

[0015] In order to facilitate the sound in the air duct to enter the sound propagation channel more smoothly, the extension line of the opening direction of the second sound inlet is consistent with the extension direction of the air duct, and the extension line of the opening direction of the first sound inlet is arranged at an angle with the extension direction of the air duct.

[0016] In order to minimize the contamination of the sound collection element in the housing by oil stains as much as possible, the orientation of the first sound inlet should be avoided to be consistent with the extension direction of the second channel section (i.e., the extension direction of the air duct), that is, the opening direction of the first sound inlet and the extension direction of the second channel section should preferably be set at an angle. However, the angle formed between the orientation of the first sound inlet and the extension direction of the second channel section also needs to be reasonably designed. For example, if the angle formed between the orientation of the first sound inlet and the extension direction of the second channel section is too small, the oil will still enter the first channel section through the first sound inlet and contaminate the sound collection element. If the angle formed between the orientation of the first sound inlet and the extension direction of the second channel section is too large, the sound propagation path will turn too much, which will have an adverse effect on sound propagation, that is, a part of the sound pressure will be lost, which is not conducive to the accurate collection of noise by the sound collection element. Therefore, the extension line of the opening direction of the first sound inlet is perpendicular to the extension direction of the air duct.

[0017] The housing can be designed with an integral structure, such as a bent pipe structure with an integral design. However, for the convenience of installing components such as the sound collection element, the housing is preferably designed with a split structure assembled by fasteners. Specifically, the housing includes a mounting frame and a wind shield. A receiving groove is formed on the front side wall of the mounting frame, and the sound collection element is placed in the receiving groove. The receiving groove constitutes the first channel section, and the front opening of the receiving groove is the first sound inlet. The wind shield covers the outside of the mounting frame and defines a sound collection channel that is connected to the first sound inlet of the receiving groove and is located in front of the receiving groove. This sound collection channel constitutes the second channel section.

[0018] Considering that the air duct is generally arranged to extend vertically, in order to be adapted thereto, the sound collection channel extends vertically, and the vertical projection of the sound collection channel does not overlap with the vertical projection of the receiving groove.

[0019] The "vertical extension" in the vertical extension of the sound collection channel is not limited to extending along the vertical direction. That is, the extension direction of the sound collection channel can have a slight inclination angle (such as 0-30°) relative to the vertical direction.

[0020] As an improvement, the sound collection device is located below the fan system of the oil fume suction device. The opening of the first sound inlet faces forward and is connected to the bottom of the sound collection channel, and the opening of the second sound inlet faces upward. Considering that the noise in the air duct (mainly from the fan system) propagates along the extension direction of the air duct, and the propagation direction is opposite to the air flow direction in the air duct. Therefore, on the basis of arranging the sound collection channel along the extension direction of the air duct, the structural design with the opening of the second sound inlet facing upward can make the second sound inlet of the sound collection channel face the sound source, so as to directly receive the noise in the air duct.

[0021] The opening of the above-mentioned first sound inlet facing forward can be forward along the horizontal direction, or slightly inclined upward or downward relative to the horizontal direction.

[0022] As an improvement, in order to further improve the windproof effect, a windproof and sound-permeable member made of porous sound-absorbing material is also provided in the sound collection channel. After setting the windproof and sound-permeable member in the sound collection channel formed between the mounting frame and the windproof cover, wind noise can be effectively eliminated. Even if a small amount of air flow enters the sound collection channel, the pressure pulsation can be weakened in the windproof and sound-permeable member, thereby reducing the impact on the sound collection accuracy of the microphone. On the other hand, more importantly, considering that the windproof and sound-permeable member is the main windproof component, it should be set with a sufficient length in the sound propagation path to achieve the purpose of effective wind noise prevention, so as to reduce the influence of the air duct air flow on sound collection. In order to install the windproof and sound-permeable member, choosing to arrange the sound collection channel in the extension direction of the air duct can make the size of the entire collection device in the direction perpendicular to the extension direction of the air duct smaller, that is, it occupies less space in the air duct of the range hood, and further makes the wind resistance at the position of the collection device in the air duct smaller, so it will not affect the stability of the air flow in the air duct, and at the same time, it also reduces the generation of wind noise to a certain extent.

[0023] In order to ensure that the setting of the windproof and sound-permeable member in the sound collection channel has sufficient windproof effect, the windproof and sound-permeable member blocks the front side of the first sound inlet and extends along the sound collection channel to the position where the second sound inlet is located.

[0024] In order to realize the diversion of the air flow and improve the windproof effect, the windproof cover has a diversion surface that gradually inclines towards the inside of the air duct along the air flow direction in the air duct. The design of the diversion surface can avoid large air flow disturbances caused by the direct impact of the air flow on the windproof cover, affecting the stability of the air flow.

[0025] Since there is a large difference in wavelength between high-frequency sound waves and low-frequency sound waves, high-frequency noise can decay rapidly as the propagation distance increases or encounters obstacles. Since the wavelength of low-frequency noise is longer, low-frequency noise is relatively stable during propagation and can penetrate obstacles. Therefore, in the preferred embodiment, the sound propagation path in the collection device adopts a turning design to increase the reflection and scattering of high-frequency sound waves and increase their resistance to propagation. For low-frequency sound waves, due to their larger wavelength size, they are not affected by the turning of the sound propagation path. Therefore, it is equivalent to adjusting the propagation characteristics of noise in different frequency bands in the channel, thereby achieving the purpose of weakening high-frequency noise and ensuring the propagation of low-frequency noise. In order to achieve the purpose of weakening high-frequency noise above the frequency f0, the sound propagation path in the collection device is divided into three areas, wherein the horizontal plane passing through the upper edge of the first sound entrance is taken as the first reference plane k1, the horizontal plane passing through the lower edge of the second sound entrance is taken as the second reference plane k2, the vertical plane where the first sound entrance is located is taken as the third reference plane k3, the horizontal plane where the second sound entrance is located is taken as the fourth reference plane k4, the vertical plane passing through the location of the sound collection element is recorded as the fifth reference plane, and the area of ​​the region located between the first reference plane and the fourth reference plane on the vertical section cut along the front-to-back direction of the sound collection channel is recorded as S 01 The area between the first reference plane and the second reference plane is denoted as S 02 The area between the third reference plane and the fifth reference plane on the vertical cross section of the receiving groove cut along the front-to-back direction is denoted as S 03 , where the values ​​of the above areas meet the conditions:

[0026]

[0027] The size of the first sound entrance 211 in the up-down direction is denoted as m, the size of the second sound entrance 45 in the left-right direction is denoted as d1, and the size of the second sound entrance 45 in the front-back direction is denoted as e. The above three satisfy the following conditions:

[0028]

[0029] Among them, f0 is the lowest noise frequency of the high-frequency noise that needs to be attenuated, and v is the speed of sound propagation.

[0030] The technical solution adopted by the utility model to solve the second technical problem is: a range hood, including an air duct for smoke to pass through and a sound collection device arranged in the air duct, and the sound collection device adopts the above-mentioned sound collection device.

[0031] As an improvement, the sound collecting element is a microphone.

[0032] Compared with the prior art, the utility model has the following advantages:

[0033] First, the extension lines of the first sound inlet opening directions of the first channel segments on the housing intersect with the extension lines of the second sound inlet opening directions of the second channel segments, which can avoid multiple turns as much as possible. On the one hand, it reduces the sound pressure loss of the sound during the propagation path, improves the accuracy of sound collection, and on the other hand, it also enables the volume of the sound collection device to be made as small as possible, avoiding adverse effects on the stability of the air flow at the installation position of the sound collection device and reducing the generation of secondary noise (wind noise), further improving the accuracy of sound collection. The above-mentioned turning path design has a weakening effect on high-frequency sounds (such as the high-frequency sound part in wind noise and the high-frequency sound components generated by the fan system and other non-target noises), and has less impact on low-frequency sounds. Therefore, it can be better applied to the propagation of low-frequency noise in the collection device, facilitating the accurate collection of it by the sound collection element.

[0034] Secondly, arranging the second channel segment of the sound propagation channel along the extension direction of the air duct and setting the second sound inlet at the leeward end of the housing can facilitate the sound collection element to directly receive the noise in the air duct. Considering that a sufficient length of the sound collection channel needs to be set on the sound propagation path for wind noise prevention to reduce the impact of the air duct air flow on sound collection, arranging the second channel segment in the extension direction of the air duct can make the size of the entire collection device in the direction perpendicular to the extension direction of the air duct smaller, that is, occupying less space in the air duct of the range hood, and further making the wind resistance at the position of the collection device in the air duct smaller. Therefore, it will not affect the stability of the air flow in the air duct, and at the same time, it also reduces the generation of wind noise to a certain extent, further improving the accuracy of sound collection. Description of the Drawings

[0035] Figure 1 is a three-dimensional structural schematic diagram of the sound collection device according to an embodiment of the present invention;

[0036] Figure 2 is an exploded view of the sound collection device according to an embodiment of the present invention;

[0037] Figure 3 is a vertical sectional view of the sound collection device according to an embodiment of the present invention;

[0038] Figure 4 is Figure 3 a structural schematic diagram after omitting the windproof sound-permeable member in

[0039] Figure 5 is a sectional view taken along the A-A direction in Figure 3 ;

[0040] Figure 6 is a three-dimensional structural schematic diagram of the sound collection device according to an embodiment of the present invention installed in the air duct;

[0041] Figure 7 is Figure 6 a transverse cross-sectional view taken along the front-rear direction;

[0042] Figure 8 is a schematic diagram of the sound propagation process at the first sound inlet of the mounting bracket. Specific Embodiments

[0043] The following further describes the present utility model in detail with reference to the embodiments in the accompanying drawings.

[0044] In the description and claims of the present utility model, terms indicating directions, such as "front", "rear", "upper", "lower", "left", "right", "side", "top", "bottom", etc., are used to describe various exemplary structural parts and elements of the present utility model. However, these terms are used herein only for the purpose of convenient description and are determined based on the exemplary orientations shown in the drawings. Since the embodiments disclosed by the present utility model can be arranged in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to the directions opposite to or consistent with the direction of gravity.

[0045] Figures 1 - 7 Shows a preferred embodiment of the sound collection device and the range hood of the present utility model.

[0046] The sound collection device includes a sound collection element 11 and a housing 2. A sound propagation channel is defined on the housing 2. Among them, the sound propagation channel includes a first channel segment and a second channel segment connected in sequence. Among them, the sound collection element 11 is located in the first channel segment. The first channel segment has a first sound inlet 211 communicating with the second channel segment. The second channel segment has a second sound inlet 45 for external sound to enter therein. The extension line of the opening direction of the first sound inlet 211 intersects with the extension line of the opening direction of the second sound inlet 45. In a preferred embodiment, both the first channel segment and the second channel segment are straight channels. Among them, the extension line of the first channel segment intersects with the extension line of the second channel segment. The extension line of the first channel segment can be understood as the connection line between the position where the sound inlet of this channel segment is located and the position where the sound collection element 11 is located. The extension line of the second channel segment can be understood as the connection line between the position where the sound inlet of this channel segment is located and the position where the sound outlet is located.

[0047] The active noise reduction system is usually installed in the air duct 10 of an oil fume extraction device (such as a range hood or an integrated stove with an oil fume extraction function, etc., which are kitchen appliances), and the sound collection device is an important part of the active noise reduction system and is also correspondingly installed in the air duct 10 of the oil fume extraction device. Taking a range hood as an example, the above-mentioned "air duct" can refer to the housing of the range hood or a box structure with a "channel" for the oil fume to pass through alone, such as the channel between the fan system and the smoke collecting hood of a ceiling-mounted range hood. The active noise reduction system generally includes a sound collection element 11 (microphone) and a speaker, that is, the microphone collects the noise generated when the range hood is working, and the collected noise sound wave is transmitted to the controller in the form of an electrical signal. After being analyzed and processed by the controller, an instruction is sent to the speaker to control the speaker to emit a sound wave that matches the noise sound wave to neutralize the noise sound wave, thereby achieving the noise reduction effect. The sound collection device of this embodiment can be used to install the above-mentioned sound collection element 11 and provide protection against oil and wind.

[0048] The sound collection device is located below the fan system, that is, the noise generated by the fan system propagates downward along the air duct 10, and the sound collection device is exactly arranged on the downward propagation path in the air duct 10. In addition to the housing, the sound collection device also includes an oil-proof sound-permeable membrane 28 and a wind-proof sound-permeable member 30. The housing includes a mounting bracket 20 and a wind-proof cover 40.

[0049] In this embodiment, taking the box body 1 with a "channel" for the oil fume to pass through alone as an example, the specific structure of the sound collection device is described. The channel in the box body 1 serves as the air duct 10. The mounting bracket 20 can be installed on the rear side wall of the air duct 10, and a receiving groove 21 for placing the sound collection element 11 is provided on its front side wall. This receiving groove constitutes the first channel section of the above-mentioned housing 2. The front part of the receiving groove 21 has an opening as the first sound inlet 211 for the sound to enter the receiving groove 21. Among them, the first sound inlet 211 should be understood as an opening for the sound from the outside (the sound collection channel in this embodiment) to enter the receiving groove 21 and be effectively collected by the sound collection element, such as Figure 8 the opening defined by the boundary points such as A1 and A2 of the receiving groove 21 in the circumferential direction, and it does not necessarily refer to the largest open mouth at the front part of the receiving groove 21. In the state where the mounting bracket 20 is installed in place on the rear side wall of the air duct 10, the rear wall of the part of the mounting bracket 20 where the receiving groove 21 is located is attached to the rear side wall of the air duct 10. In order to improve the accuracy of sound collection of the active noise reduction system, generally two or more sound collection elements 11 are arranged, and for this reason, components such as the mounting bracket 20, the wind-proof sound-permeable member 30, and the wind-proof cover 40 are also correspondingly provided with two or more.

[0050] The mounting bracket 20 further has a third mounting portion 263 that extends respectively to the left and right sides and exposes outside the wind deflector 40, and a fourth mounting portion 264 that extends downward at the bottom of the mounting bracket 20 and exposes outside the wind deflector 40. Both the third mounting portion 263 and the fourth mounting portion 264 are connected to the side wall of the air duct 10 by screws. In the lower region of the receiving groove 21 of the mounting bracket 20, there is a connecting post 265 that extends forward, and the wind deflector 40 can be connected to the connecting post 265 of the mounting bracket 20 by screws 50.

[0051] The wind deflector 40 includes a first side wall 411 and a second side wall 412 that are opposite and spaced apart from each other left and right, and a third side wall 413 that is connected between the front side edges of the first side wall 411 and the second side wall 412. The third side wall 413 of the wind deflector 40 is located in front of the receiving groove 21 of the mounting bracket 20. On the third side wall 413 of the wind deflector 40, there is a guiding surface 4130 that gradually inclines towards the inside of the air duct 10 along the air flow direction in the air duct 10 (as shown by the hollow arrow in Figure 3 ). Specifically, the guiding surface 4130 is located at the lower part of the third side wall 413, that is, at the windward end of the third side wall 413, and it inclines forward from bottom to top, while the upper part of the third side wall 413 is basically vertically extended and is opposite to the part where the receiving groove 21 of the mounting bracket 20 is located in the front-rear direction. Along the air flow direction in the air duct 10, the position where the guiding surface 4130 of the wind deflector 40 is located is upstream of the position where the receiving groove 21 of the mounting bracket 20 is located. Arranging the guiding surface 4130 of the wind deflector 40 at a lower position also enables sufficient space to arrange components such as the windproof sound-permeable member 30 and the oil-proof sound-permeable film 28 at the position in the wind deflector 40 opposite to the front part of the receiving groove 21. In addition, considering that if the inclination angle of the guiding surface 4130 towards the inside of the air duct 10 is too large, it will also affect the air flow in the air duct 10 to a certain extent, such as affecting the air volume flowing in the air duct 10 or generating additional noise problems. Therefore, the inclination angle of the guiding surface 4130 of the wind deflector 40 needs to be reasonably designed. The included angle formed between the guiding surface 4130 of the wind deflector 40 and the side wall of the air duct 10 for installing the wind deflector 40 is denoted as A, and the value range of A is: A ≤ 60°. In order to reduce the influence of the installation of the sound collection device on the flow field in the air duct 10, the dimension of the air duct 10 in the front-rear direction in this embodiment is denoted as a, and the distance that the wind deflector 40 protrudes forward relative to the side wall of the air duct 10 for installing the wind deflector 40 is denoted as b. Considering that if the protruding distance of the wind deflector 40 forward is too large, such as b / a > 0.35, on the one hand, it will affect the air volume flowing in the air duct 10, and on the other hand, it will also cause a turbulence problem of the air flow at the position of the sound collection device in the air duct 10, generating additional noise and affecting the accuracy of sound collection. Therefore, the value of b / a needs to be reasonably limited. In this embodiment, preferably, b / a ≤ 0.35, see Figure 7 .

[0052] To improve the anti-oil pollution effect, the wind shield 40 in this embodiment can be made of plastic parts or metal parts.

[0053] In this embodiment, a vertically extending gap channel is formed between the front side of the wind shield 40 and the mounting frame 20 in the front-rear direction. The upper end of the gap channel (i.e., the end close to the noise source) is open, and the lower end (i.e., the end far from the noise source) is closed, which is the sound collection channel 200. The sound collection channel 200 is located on the front side of the mounting frame 20, that is, it constitutes the second channel section of the above-mentioned housing 2. More specifically, a second sound inlet 45 communicating with the above-mentioned sound collection channel 200 is defined between the windward end of the wind shield 40 (i.e., a section along the extension direction of the air duct, close to the fan system of the range hood) and the front side wall of the mounting frame 20. The opening direction B4 of the second sound inlet 45 faces upward. The air duct 10 and the sound collection channel 200 in this embodiment both extend vertically, that is, the extension direction of the sound collection channel 200 is the same as the extension direction B2 of the air duct 10. The opening direction B1 of the first sound inlet 211 intersects with the extension direction B3 of the sound collection channel 200 to form a first angle M. Considering that if the angle formed between the orientation B1 of the first sound inlet 211 and the extension direction B3 of the sound collection channel 200 is too small, the oil liquid will still enter the receiving groove 21 through the first sound inlet 211 to contaminate the sound collection element 11. If the angle formed between the orientation B1 of the first sound inlet 211 and the extension direction B3 of the sound collection channel 200 is too large, the sound propagation path will turn too much, which will have an adverse effect on sound propagation, that is, a part of the sound pressure will be lost, and it is not conducive to the accurate collection of noise by the sound collection element. Therefore, in this embodiment, the opening direction B1 of the first sound inlet 211 faces forward and is perpendicular to the extension direction B3 of the sound collection channel 200, that is, the value of the above-mentioned first angle M is 90°. In this way, the entire sound propagation path for the noise in the air duct 10 to enter the sound collection channel 200 from the second sound inlet 45 and then propagate to the position of the sound collection element 11 in the receiving groove 21 is a turning path. This turning path can prevent too much oil stain from directly passing through the sound collection channel 200 and contacting the sound collection element 11, but make most of the oil stain adhere to the side wall of the sound collection channel 200 or the windproof and sound-transmitting member 30, thereby enabling the sound collection element 11 to be as far away from the oil stain as possible and extending the service life of the sound collection element 11. On the other hand, considering that the target noise (mainly from the fan system) that the active noise reduction system needs to collect is low-frequency noise, and the sound propagation path in the sound collection device is designed with a turning path, it has a weakening effect on high-frequency sounds (such as the high-frequency sound part of the wind noise and the high-frequency sound components generated by the fan system, etc., which are non-target noises), and has little impact on low-frequency sounds. Therefore, it can be better applied to the propagation of low-frequency noise in the sound collection device, which is conducive to the accurate collection of it by the sound collection element 11. The main reason is that the wavelength of low-frequency noise is longer, and it can better adapt to the bending and irregular shapes of the pipeline.When low-frequency noise propagates in a curved pipe, due to its longer wavelength, it is not easily blocked or reflected by the pipe, so it can propagate and disperse better. On the other hand, high-frequency noise has a shorter wavelength and is easily reflected and absorbed by the shape and curvature of the pipe, so it is more difficult to propagate and disperse in the pipe compared to low-frequency noise.

[0054] The lower part of the sound collection channel 200 is opposite to the first sound inlet 211 at the front of the accommodation groove 21 of the mounting bracket 20 in the front-rear direction. After the wind shield 40 is installed, it can effectively prevent the high-speed oil fume airflow from directly impacting the windproof sound-transmitting member 30, greatly reducing the pollution of the oil fume to the windproof sound-transmitting member 30. At the same time, after the wind shield 40 is combined with the mounting bracket 20, only the second sound inlet 45 at the upper part is retained, directly isolating the lower airflow noise and the noise interference of the secondary turbulent flow, so that the noise entering the windproof sound-transmitting member 30 mainly comes from above, that is, the direction of the main noise source of the range hood, thus ensuring the accuracy of noise collection. In a preferred embodiment, in order to improve the protection effect of the wind shield 40 on the windproof sound-transmitting member 30 and minimize the contact between the windproof sound-transmitting member 30 and the flue gas in the air duct, the upper edge of the wind shield 40 extends upward relative to the top surface of the windproof sound-transmitting member 30 to form an extension wall 46, that is, the top edge of the extension wall 46 is higher than the top surface of the windproof sound-transmitting member 30. Affected by the airflow in the air duct 10, an airflow vortex will be formed at the leeward end of the wind shield 40 (that is, at the second sound inlet 45), which will generate obvious wind noise. The setting of the extension wall 46 of the wind shield 40 can make the airflow vortex as far away from the second sound inlet 45 as possible, avoiding the influence of the airflow vortex on the target noise to be collected entering from the second sound inlet 45.

[0055] Since the sound collection element 11 is installed in the receiving groove 21 of the mounting bracket 20 and a windproof cover 40 is provided outside the mounting bracket 20, the interference of the airflow in the air duct 10 to the sound collection element 11 can be effectively isolated, and the sound collection element 11 can be prevented from being contaminated by the oil stain in the airflow. At the same time, a windproof and sound-permeable member 30 is provided in the sound collection channel formed between the mounting bracket 20 and the windproof cover 40, which can effectively reduce the influence of wind noise. Even if a small amount of airflow enters the sound collection channel 200, the pressure pulsation can be weakened in the windproof and sound-permeable member 30, thereby reducing the influence on the sound collection accuracy of the microphone. In addition, considering that the noise in the air duct 10 (mainly from the fan system) propagates along the extension direction of the air duct 10 and the propagation direction is opposite to the airflow direction in the air duct 10, therefore, the sound collection channel 200 is arranged along the extension direction of the air duct, and the opening of the second sound inlet 45 faces upward, so that the second sound inlet 45 of the sound collection channel 200 faces the sound source, so as to directly receive the noise. And considering that a windproof and sound-permeable member 30 with a sufficient length needs to be provided on the sound propagation path to prevent wind noise, thereby reducing the influence of the airflow in the air duct 10 on sound collection. In this embodiment, the sound collection channel 200 for placing the windproof and sound-permeable member 30 is arranged in the extension direction of the air duct 10, so that the size of the entire sound collection device in the direction perpendicular to the extension direction of the air duct can be made smaller, that is, it occupies less space in the air duct 10 of the range hood, and further makes the wind resistance at the position where the sound collection device is located in the air duct 10 smaller. Therefore, it will not affect the stability of the airflow in the air duct 10 and at the same time reduce the generation of wind noise to a certain extent.

[0056] The oil-proof and sound-permeable film 28 covers the first sound inlet 211 of the receiving groove 21 of the mounting bracket 20, specifically at the position where the edge of the front opening of the receiving groove 21 of the mounting bracket 20 is located. More specifically, in order to facilitate the installation of the oil-proof and sound-permeable film 28 and ensure its sealing performance after installation, an annular step portion 210 is further formed at the edge position of the first sound inlet 211 of the receiving groove 21, and the oil-proof and sound-permeable film 28 is provided on the annular step portion 210. In order to ensure the oil-proof performance of the oil-proof and sound-permeable film 28 and enable it to effectively transmit sound waves, the oil-proof and sound-permeable film 28 of this embodiment is preferably a polyethylene film. Among them, as Figure 3As shown, there is a fourth spacing between the oil-proof and sound-transmitting film 28 and the sound collection element 11, which is denoted as f. Among them, the value range of f is: f ≥ 0.1 mm, the preferred range is: 0.5 - 3 mm, and the more preferred range is: 2 - 3 mm. Thus, it is avoided that the film vibrates or undergoes micro-deformation and contacts the sound collection element 11, resulting in sound transmission variation and affecting the accuracy of sound collection. It can be understood that the fourth distance f between the oil-proof and sound-transmitting film 28 and the sound collection element 11 should refer to the distance between the oil-proof and sound-transmitting film 28 and the microphone chip on the sound collection element 28, that is, the oil-proof and sound-transmitting film 28 can have partial contact with other components (such as solder joints or fixing screws, etc.) on the circuit board where the microphone chip is located.

[0057] In order to achieve the purpose of effectively slowing down the airflow and eliminating the airflow impact, the wind-proof and sound-transmitting member 30 is a sleeve member made of a porous sound-absorbing material. For example, the wind-proof and sound-transmitting member 30 can be made of polyurethane foam, melamine foam sponge, etc. Among them, the porosity of the wind-proof and sound-transmitting member 30 is greater than 70%. The wind-proof and sound-transmitting member 30 of this embodiment can not only avoid the airflow impact on the oil-proof and sound-transmitting film 28 and thus generate additional noise, but also, due to the property of its own porous material, can absorb the high-frequency components in the sound energy and realize the filtering function of filtering the noise signal. More specifically, the front side wall of the wind-proof and sound-transmitting member 30 is attached to the rear side wall of the third side wall 413 of the wind-proof cover 40, so that the wind-proof and sound-transmitting member 30 is in a compressed state. By compression, the material density can be increased, and the possibility of the penetration of the airflow pressure pulsation can be effectively reduced, thereby further improving the wind-proof effect. In order to avoid the oil-proof and sound-transmitting film 28 contacting the wind-proof and sound-transmitting member 30 and affecting the sound transmission effect here, the sixth distance n between the oil-proof and sound-transmitting film 28 and the wind-proof and sound-transmitting member 30 should be greater than 0.1 mm, and the preferred range is 0.5 mm - 3 mm.

[0058] The windproof sound-transmitting member 30 of this embodiment includes an extension section 301 extending upward from the top edge of the first sound inlet 211 of the accommodating groove 21. The length of the extension section 301 of the windproof sound-transmitting member 30 is denoted as h, and the dimension of the first sound inlet 211 of the accommodating groove 21 in the vertical direction is m. Among them, the value range of h / m is: 0.125 ≤ h / m ≤ 0.6. Since the sound collection channel 200 has a vertical section extending vertically and a horizontal section extending in the front and rear directions, that is, there is a turning part at the first sound inlet 211 of the accommodating groove 21. If the extension length of the outer peripheral edge part of the windproof sound-transmitting member 30 relative to the edge of the first sound inlet 211 of the accommodating groove 21 is too short (such as h / m is less than 0.125), it will also be affected by relatively large wind noise. After the above parameter design, the windproof effect of the windproof sound-transmitting member is effectively guaranteed, and the influence on the accuracy of sound collection caused by the too short extension length of the outer peripheral edge of the windproof sound-transmitting member is avoided. Of course, considering the adverse effect of the windproof sound-transmitting member 30 on sound attenuation, the length dimension of the extension section 301 of the windproof sound-transmitting member 30 should not be too large. If h / m is greater than 0.6, it will cause the sound not to effectively meet the sound pressure requirements of the sound collection element 11 when propagating to the accommodating groove 21, reducing the accuracy of noise collection.

[0059] In order to prevent the windproof sound-transmitting member 30 from contacting the oil liquid continuously flowing down on the side wall of the air duct 10, there is a first distance between the windproof sound-transmitting member 30 and the rear side wall of the air duct 10 after being installed on the mounting bracket 20. This first distance is denoted as d. Among them, the value range of d is: d ≥ 4 mm. Similarly, in order to ensure the windproof effect, the dimension (i.e., thickness) of the main body of the windproof sound-transmitting member 30 in the front and rear directions is denoted as e. Among them, the value range of e is: 40 mm ≥ e ≥ 3 mm. Specifically, when e ≥ 3 mm, it can ensure that the windproof sound-transmitting member 30 effectively prevents the air flow in the air duct from directly impacting the sound collection element 11. Of course, considering the adverse effect of the windproof ball 30 (generally made of porous materials that can prevent air flow disturbance and transmit sound) on sound attenuation, the dimension (i.e., thickness) of the windproof sound-transmitting member 30 in the front and rear directions cannot be too large either, and e ≤ 40 mm is required. At the same time, when the dimension (i.e., thickness) of the windproof sound-transmitting member 30 in the front and rear directions is certain, the dimension d1 of the main body of the windproof sound-transmitting member 30 in the left and right directions also needs to be adapted to it, that is, it is necessary to reasonably limit e / d1. Specifically, if e / d1 is too small (such as e / d1 < 0.2), it means that the dimension of the main body of the windproof sound-transmitting member 30 in the left and right directions is large, and the area of its upper part in contact with the oil stain increases, which will directly affect the service life of the windproof sound-transmitting member 30. If e / d1 is too large (such as e / d1 > 0.5), it means that the dimension of the main body of the windproof sound-transmitting member 30 in the left and right directions is small, which is not conducive to the sound being transmitted into the sound collection channel 200 from a large angle range in the horizontal direction above, affecting the accuracy of sound collection.

[0060] Due to the setting of the windproof sound-permeable member 30 in the sound acquisition channel 200, there will be a certain loss in the propagation path of the sound from the second sound inlet 45 to the position where the sound acquisition element 11 is located, that is, a part of the sound pressure will be lost. Therefore, it is necessary to ensure that a sufficient amount of noise to be acquired enters the accommodation groove 21 of the mounting bracket 20 to be received by the sound acquisition element 11 and achieve the purpose of accurately acquiring the noise signal. Specifically, the principle of sound attenuation and compensation is as follows:

[0061] L w = L1 - ΔL + 10lgS0

[0062] Among them, the noise energy that the sound acquisition component can acquire per unit time is the sound power L w ;

[0063] The sound pressure when the sound reaches the top surface of the windproof sound-permeable member 30 is L1;

[0064] Due to the attenuation effect of the windproof sound-permeable member 30, the lost noise sound pressure is ΔL;

[0065] The cross-sectional area S0 of the second sound inlet 45 of the sound acquisition channel 200;

[0066] Therefore, if the thickness of the windproof sound-permeable member 30 or the length dimension in the sound propagation path is too large, resulting in serious sound attenuation, then by increasing S0, the sound power L acquired by the sound acquisition element can be ensured w will not become smaller, thereby ensuring the accuracy of sound acquisition. Specifically, the ratio of the cross-sectional area S0 of the second sound inlet 45 of the sound acquisition channel 200 in this embodiment to the opening area S of the first sound inlet 211 at the front of the accommodation groove 21O needs to be reasonably limited. Among them, S0 / S ≥ 0.18, so as to ensure that enough noise can pass through the sound acquisition channel 200 of the sound acquisition device to compensate for the sound pressure lost due to the setting of the windproof sound-permeable member 30, and further ensure that the sound can meet the sound pressure requirements of the sound acquisition element 11 when propagating to the second sound inlet 45, further improving the accuracy of noise acquisition.

[0067] On the other hand, the dimension of the main body of the windproof sound-permeable member 30 in the up and down direction in this embodiment is denoted as g. In order to adapt to the dimension of the first sound inlet 211 at the front of the accommodation groove and ensure the windproof effect, 100mm ≥ g ≥ 10mm. The cross-sectional area of the main body of the windproof sound-permeable member 30 near the second sound inlet 45 is S1. Among them, g / 2 + e / 2 represents the sound propagation path length in the windproof sound-permeable member. When the propagation path is long, the sound loss is more. According to the sound propagation principle L w = L1 + 101gS(L W(where \(W\) is the sound power, \(L_1\) is the sound pressure, and \(S\) is the area of the sound inlet), it can be seen that due to sound loss, the sound pressure decreases during sound propagation. As a compensation, \(S_1\) should be increased at this time to ensure that enough sound is collected by the sound collection element. Therefore, considering sound propagation loss and compensation, the value of \(S_1 / (g / 2 + e / 2)\) should be greater than 8 mm, and the preferred value range is: 10 mm to 15 mm. If \(S_1 / (g / 2 + e / 2)\) is too small, such as \(S_1 / (g / 2 + e / 2)\leq8\), it means that the inlet area for the sound to effectively transmit from top to bottom at the end position of the windproof sound-permeable member adjacent to the second sound inlet is small, and the amount of sound entering is not enough to balance the adverse effects of the windproof sound-permeable member 30 on sound loss in the up-down direction and the front-back direction, reducing the accuracy of the sound collected by the sound collection element 11. If \(S_1 / (g / 2 + e / 2)\) is too large, such as \(S_1 / (g / 2 + e / 2)\geq15\), it means that the inlet area for the sound to effectively transmit from top to bottom at the end position of the windproof sound-permeable member 30 adjacent to the second sound inlet 45 is large. Similarly, the area of the upper part of the windproof sound-permeable member 30 in contact with oil stains increases, affecting the service life of the windproof sound-permeable member 30.

[0068] In this embodiment, since the windproof sound-permeable member 30 is filled in the sound collection channel 200, that is, there is no gap between the front side of the windproof sound-permeable member 30 and the windproof cover 40. Therefore, the cross-sectional area \(S_1\) of the main body of the windproof sound-permeable member 30 at the position adjacent to the second sound inlet 45 is basically the same as the cross-sectional area \(S_0\) of the second sound inlet 45 of the sound collection channel 200.

[0069] While the protection structure of this embodiment realizes the suppression of wind noise by the sound collection element, it also needs to ensure the passage of noise signals. According to the sound propagation theory, the protection structure consists of a sound mass \(M\) a and a sound capacitance \(C\) a to form a low-pass filter. Therefore, it is necessary to make the cut-off frequency \(f\) c of the structure itself greater than the upper frequency limit \(f\) a concerned by active noise cancellation, so as to accurately collect all the original noise frequencies concerned by active noise cancellation.

[0070] Among them:

[0071]

[0072] \(V\) is the volume of the cavity in the protection structure, specifically the volume of the inner cavity formed by the oil-proof sound-permeable membrane and the inner wall of the accommodation groove of the mounting frame; \(\rho_0\) is the air density; \(c_0\) is the speed of sound in air, 343 m / s; \(L\) is the path length of sound propagation;

[0073] S0 is the effective area for the sound propagation in the pipeline, and can be simplified as the minimum cross-sectional area of the pipeline during the sound propagation process. In this embodiment, S0 is the area of the cross-section at the second sound inlet 45 of the sound collection channel 200;

[0074]

[0075] The applicant's research finds that due to the structural limitations of the range hood and the noise source and its propagation characteristics, the upper frequency limit f a for the active noise reduction of the range hood should be 1200 - 2000 Hz. Therefore, it can be obtained that:

[0076]

[0077] After simplification, it is:

[0078]

[0079] The protection structure of this embodiment must meet the requirements of the above formula.

[0080] More specifically, in this embodiment, S0 is the area of the cross-section at the second sound inlet 45 of the sound collection channel 200, where the second sound inlet 45 is a strip-shaped opening. Thus:

[0081] S0 = ed;

[0082] L is the path length of the sound propagation. Since the sound collection channel 200 in this embodiment is not a regular pipeline, it can be simplified as:

[0083]

[0084] Among them, the size of the windproof and sound-permeable member 30 in the up and down direction is denoted as g, and the size (i.e., the thickness) of the main body of the windproof and sound-permeable member 30 in the front and back direction is denoted as e.

[0085] The above

[0086] After further simplification, it is obtained:

[0087]

[0088] Since there is a large difference between the wavelengths of high-frequency sound waves and low-frequency sound waves, high-frequency noise can be rapidly attenuated as the propagation distance increases or when encountering obstacles. Since the wavelength of low-frequency noise is longer, low-frequency noise is relatively stable during the propagation process and can penetrate obstacles. Therefore, the sound propagation path in the sound collection device of this embodiment adopts a turning design to increase the reflection and scattering of high-frequency sound waves and increase their propagation resistance. For low-frequency sound waves, due to their large wavelength size, they are not affected by the turning of the sound propagation path. Therefore, it is equivalent to adjusting the propagation characteristics of noise in different frequency bands in the channel, thereby achieving the purpose of weakening high-frequency noise and ensuring the propagation of low-frequency noise. In order to achieve the purpose of weakening high-frequency noise above frequency f0, refer to Figure 4 , the sound propagation path in the sound collection device is divided into three areas, wherein the horizontal plane passing through the upper edge of the first sound entrance 211 is taken as the first reference plane k1, the horizontal plane passing through the lower edge of the first sound entrance 211 is taken as the second reference plane k2, the vertical plane where the first sound entrance 211 is located is taken as the third reference plane k3, the horizontal plane where the second sound entrance 45 is located is taken as the fourth reference plane k4, and the vertical plane passing through the position where the sound collection element 11 is located is recorded as the fifth reference plane k5. The area of ​​the area between the first reference plane k1 and the fourth reference plane k4 on the vertical section of the sound collection channel 200 cut along the front-to-back direction is recorded as S 01 The area between the first reference plane k1 and the second reference plane k2 is denoted as S 02 The area of ​​the vertical cross section of the receiving groove 21 cut along the front-to-back direction between the third reference plane k2 and the fifth reference plane k5 is denoted as S 03 , where the values ​​of the above areas meet the conditions:

[0089]

[0090] The size of the first sound entrance 211 in the up-down direction is denoted as m, the size of the second sound entrance 45 in the left-right direction is denoted as d1, and the size of the second sound entrance 45 in the front-back direction is denoted as e. The above three satisfy the following conditions:

[0091]

[0092] Among them, f0 is the lowest noise frequency of the high-frequency noise that needs to be attenuated, and v is the speed of sound propagation.

[0093] After installing the sound collection element 11 in the accommodation groove 21 of the mounting bracket 20 in this embodiment, an oil-proof sound-transmitting film 28 is provided at the first sound inlet 211 thereof, a wind-proof sound-transmitting member 30 is provided outside thereof, and a wind-proof cover 40 is provided outside the wind-proof sound-transmitting member 30. This kind of sound collection device adopts the above three-layer protection to effectively eliminate wind noise and achieve the purpose of preventing oil pollution. After the wind-proof cover 40 covers the wind-proof sound-transmitting member 30, a second sound inlet 45 communicating with the outside is reserved at the leeward end. According to the law of air flow, the flow in the area of the wind-proof sound-transmitting member 30 adjacent to the second sound inlet 45 is a low-speed and high-static-pressure area. The existence of the low-speed and high-static-pressure area reduces the wind noise here, and further ensures that the target noise to be collected (i.e., the noise of the fan system) can be effectively transmitted to the accommodation groove 21 of the mounting bracket 20 through the second sound inlet 45, ensuring the accuracy of noise data collection. On the other hand, considering the influence of the wind-proof sound-transmitting member 30 and the wind-proof cover 40 on the sound propagation obstruction and loss, the ratio of the opening area S at the first sound inlet of the accommodation groove 21 to the opening area S0 at the second sound inlet 45 of the sound collection channel 200 is limited within a reasonable value range, which can ensure that enough noise passes through this sound collection device and is received by the sound collection element, further improving the accuracy of noise collection.

[0094] This embodiment also relates to a range hood, which includes a flue 1O for the flue gas to pass through and an active noise reduction system provided in the flue 1O. The active noise reduction system includes the above-mentioned sound collection device.

Claims

1. A sound collection device for an oil fume extraction device, which is arranged in the air duct (10) of the oil fume extraction device and includes a sound collection element (11), and is characterized in that: It further includes a housing (2) on which a sound propagation channel is defined. The sound propagation channel includes a first channel section and a second channel section connected in sequence. The sound collection element (11) is located in the first channel section. The first channel section has a first sound inlet (211) communicating with the second channel section. The second channel section is arranged along the extension direction of the air duct (10), and a second sound inlet (45) for the sound in the air duct (10) to enter the second channel section is formed at the windward end of the housing (2). The extension line of the opening direction of the first sound inlet (211) intersects with the extension line of the opening direction of the second sound inlet (45).

2. The sound collection device for a fume extraction device according to claim 1, wherein: Both the first channel section and the second channel section are straight channel sections, and the extension line of the first channel section intersects with the extension line of the second channel section.

3. The sound collection device for an oil fume extraction device according to claim 1, characterized in that: The extension line of the opening direction of the second sound inlet (45) is consistent with the extension direction of the air duct (10), and the extension line of the opening direction of the first sound inlet (211) is arranged at an angle with the extension direction of the air duct (10).

4. The sound collection device for the oil fume extraction device according to claim 3, characterized in that: The extension line of the opening direction of the first sound inlet (211) is perpendicular to the extension direction of the air duct (10).

5. The sound acquisition device for the oil fume suction device according to any one of claims 1 to 4, characterized in that: The housing (2) includes a mounting bracket (20) and a wind shield (40). A receiving groove (21) is formed on the front side wall of the mounting bracket (20). The sound collection element (11) is placed in the receiving groove (21). The receiving groove (21) constitutes the first channel section, and the front opening of the receiving groove (21) is the first sound inlet (211). The wind shield (40) covers outside the mounting bracket (20), and a sound collection channel (200) communicating with the first sound inlet (211) of the receiving groove (21) and located on the front side of the receiving groove (21) is defined between the wind shield (40) and the mounting bracket (20). The sound collection channel (200) constitutes the second channel section.

6. The sound collection device for the oil fume extraction device according to claim 5, characterized in that: The sound collection channel (200) extends vertically, and the vertical projection of the sound collection channel (200) does not overlap with the vertical projection of the receiving groove (21).

7. The sound collection device for the oil fume suction device according to claim 6, wherein: The sound collection device is located below the fan system of the oil fume suction device. The opening of the first sound inlet (211) faces forward and is connected to the bottom of the sound collection channel (200), and the opening of the second sound inlet (45) faces upward.

8. The sound collection device for the oil fume extraction device according to claim 5, characterized in that: A windproof and sound-permeable member (30) made of porous sound-absorbing material is further provided in the sound collection channel (200).

9. The sound collection device for the oil fume suction device according to claim 8, characterized in that: The windproof and sound-permeable member (30) blocks the front side of the first sound inlet (211) and extends along the sound collection channel (200) to the position where the second sound inlet (45) is located.

10. The sound collection device for the oil fume extraction device according to claim 5, wherein: One end of the wind shield (40) facing the wind has a guiding surface (4130) that gradually inclines towards the inside of the air duct (10) along the air flow direction in the air duct (10).

11. The sound collection device for the oil fume suction device according to claim 5, wherein: Taking the horizontal plane passing through the upper edge of the first sound inlet (211) as the first reference plane, the horizontal plane passing through the lower edge of the first sound inlet (211) as the second reference plane, the vertical plane where the first sound inlet (211) is located as the third reference plane, the horizontal plane where the second sound inlet (45) is located as the fourth reference plane, and the vertical plane passing through the position of the sound collection element (11) is denoted as the fifth reference plane. The area of the region between the first reference plane and the fourth reference plane in the vertical section of the sound collection channel (200) cut along the front-back direction is denoted as S 01 , the area of the region between the first reference plane and the second reference plane is denoted as S 02 , the area of the region between the third reference plane and the fifth reference plane in the vertical section of the accommodation groove (21) cut along the front-back direction is denoted as S 03 , where S 01、 S 02 , S 03 satisfy the condition: The dimension of the first sound inlet (211) in the up-down direction is denoted as m, the dimension of the second sound inlet (45) in the left-right direction is denoted as d1, and the dimension of the second sound inlet (45) in the front-back direction is denoted as e. m, d1, and e satisfy the condition: Where f0 is the lowest noise frequency of the high-frequency noise that needs to be attenuated, and v is the sound propagation speed.

12. A range hood, comprising an air duct (10) for flue gas to pass through and a sound collection device disposed in the air duct (10), characterized in that: The sound collection device adopts the sound collection device described in any one of claims 1 to 11.

13. The range hood according to claim 12, characterized in that: The sound collection element (11) is a microphone.

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