Sound acquisition device and range hood

Abstract

The sound collection device comprises a sound collection element and further comprises a shell, a sound transmission channel is defined on the shell, the sound transmission channel comprises a first channel section and a second channel section, and the first channel section and the second channel section are connected in sequence and arranged at an included angle. The sound collection 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 provided with a second sound inlet for external sound to enter, a windproof sound transmission part is further arranged in the second channel section, the opening area of the first sound inlet is recorded as S, and the opening area of the second sound inlet is recorded as S; the opening area of the second sound inlet is recorded as S0, and the value range of S0 / S is that S0 / S is greater than or equal to 0.18. The device has the advantages of being good in windproof effect and capable of guaranteeing the accuracy of sound collection.

Description

Technical Field

[0001] The present invention relates to the technical field of range hoods, and particularly to a sound collection device and a range hood. Background Art

[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 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 inside 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 inside the 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 the reduction of the noise reduction effect of the active noise reduction system as the use time becomes longer, and even malfunction. For this reason, 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-proof device, including an incoming device, a central data processor and a noise reduction unit. The incoming device includes a microphone, and the microphone is arbitrarily installed at a place of the range hood. The noise reduction unit includes at least two noise reduction boxes, and the noise reduction boxes are arranged at the bottom of the volute of the range hood, facing the air inlet. An oil-proof device is arranged below the noise reduction box, and the oil-proof device is also arranged at the bottom of the volute and covers the noise reduction box. The oil-proof 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 arranged inside the noise reduction box. The microphone and the noise reduction speaker are both 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-proof 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 arranged in the self-check module.

[0004] However, the oil-proof device of the active noise reduction device of the above-mentioned patent application still has certain deficiencies. The oil-proof device realizes sound transmission and oil prevention by means of a porous sound-permeable shell and an oil-proof film attached to the surface of the porous sound-permeable shell. The influence of wind noise in the air duct of the range hood is not taken into consideration, that is, no effective wind noise prevention treatment is performed. On the other hand, if the number of openings of the porous sound-permeable shell is large, it will have an adverse effect on oil prevention and wind prevention. If the number of openings is small, the noise will be lost more during the propagation process, resulting in the accuracy of sound collection being affected. Therefore, how to provide a sound collection device that can effectively prevent oil and achieve the purpose of wind prevention, thereby ensuring the accuracy of sound collection has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a sound collection device with good windproof effect and capable of ensuring the accuracy of sound collection in view of the current status of the existing technology.

[0006] The second technical problem to be solved by the present invention is to provide a range hood using the above-mentioned sound collection device in view of the current status of the existing technology.

[0007] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is: a sound collecting device, including a sound collecting element and a shell, the shell defining a sound propagation channel, the sound propagation channel including a first channel section and a second channel section connected in sequence and arranged at an angle, the sound collecting element is located in the first channel section, the first channel section has a first sound inlet connected to the second channel section, the second channel section has a second sound inlet for external sound to enter, and the second channel section is also provided with a windproof and sound-permeable component, the opening area at the first sound inlet is denoted as S, and the area of the cross section formed by the windproof and sound-permeable component cut in the extension direction of the second channel section is denoted as S3, wherein the value range of S3 / S is: 13.5≥S3 / S≥1.5.

[0008] The sound collecting element is installed in the first channel section of the shell, and a windproof and sound-permeable member is set in the second channel section of the shell, which can effectively prevent the airflow from interfering with the sound collecting element, effectively eliminating wind noise and preventing the sound collecting element from being contaminated by oil. On the other hand, the installation of windproof and sound-permeable members in the sound collecting channel will have an adverse effect on sound transmission, that is, a part of the sound pressure will be lost. According to the sound transmission principle, w =L1+101gS(L Wis sound power, L1 is sound pressure, and S is the area at the sound entrance) It can be seen that the extension direction dimension of the windproof and sound-permeable component cannot be designed to be too large, otherwise the loss of sound pressure L1 will increase due to the excessive size design of the windproof and sound-permeable component. On the other hand, when the sound pressure is lost, as compensation, the opening area S at the first sound entrance of the first channel section can also be used to maintain the sound power. Of course, in order to ensure the windproof performance of the windproof and sound-permeable component and ensure that the airflow pressure pulsation does not affect the sound collecting components, the size of the windproof and sound-permeable component cannot be designed to be too small. For this reason, the value of S3 / S needs to be reasonably designed: 13.5≥S3 / S≥1.5. When S3 / S is too small (such as less than 1.5), it means that the size of the windproof and sound-permeable component is small, and the area of the first sound entrance is too large, resulting in poor windproof effect, which will affect the accuracy of sound collection; when S3 / S is too large (such as greater than 13.5), it means that the size of the windproof and sound-permeable component is large, and the area of the first sound entrance is too small, which will cause more sound loss when passing through the windproof and sound-permeable component, and it will be difficult for the sound to meet the sound pressure requirements of the sound collection component when it propagates to the accommodating groove. In this application, the ratio of the area S3 of the cross section formed by the windproof and sound-permeable component in the extension direction of the second channel segment to the opening area S at the first sound entrance at the front of the first channel segment needs to be limited to a reasonable value range (13.5≥S3 / S≥1.5). On the basis of ensuring that the windproof and sound-permeable component has a relatively good windproof effect, it avoids the sound loss caused by the excessive size of the windproof and sound-permeable component when passing through the windproof and sound-permeable component, so that the sound can meet the sound pressure requirements of the sound collection component when it propagates to the first channel segment, thereby improving the accuracy of noise collection. When S3 / S is less than 1.5, the size of the windproof and sound-permeable component is too small, and the protection of the first sound entrance is insufficient, causing it to be affected by the airflow pressure pulsation; the accuracy of sound collection is poor, less than 75%, and the collected noise is generally higher than the original noise; when S3 / S is greater than 13.5, the windproof and sound-permeable component is too large, causing it to weaken the sound more, making the accuracy less than 80%. At this time, the collected noise is generally smaller than the original noise, so it is not recommended.

[0009] Considering that the air duct environment of the range hood is full of oil stains, in order to prevent the sound collection element from being contaminated by the oil stains flowing down along the air duct, in the present invention, the first channel section and the second channel section are arranged at an angle. This makes the entire path of the noise in the air duct entering the second channel section from the second sound inlet and then propagating to the position of the sound collection element in the first channel section a turning path. This turning path can prevent excessive oil stains from directly passing through the sound propagation channel and contacting the sound collection element, but instead causes most of the oil stains to adhere to the side wall of the second channel section or the windproof sound-permeable member. Thereby, the sound collection element can be kept as far away from the oil stains as possible, extending the service life of the sound collection element. 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 adopts a turning path design, which 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 and other 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, facilitating the accurate collection of the low-frequency noise by the sound collection element. 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 bent pipeline, due to its longer wavelength, it is not easily blocked and reflected by the pipeline, so it can better propagate and spread. While the wavelength of high-frequency noise is shorter, and it is easily reflected and absorbed by the shape and bending of the pipeline, so it is more difficult to propagate and spread in the pipeline compared to low-frequency noise.

[0010] More specifically, when the value range of S3 / S is 1.5 ≤ S3 / S < 2.5, at this time, the windproof effect of the sound-permeable windproof layer will be significantly enhanced, and the accuracy of sound collection can reach about 80%. When the value range of S3 / S is 2.5 ≤ S3 / S ≤ 13.5, the windproof effect of the sound-permeable windproof layer is relatively excellent, the loss of the target noise during transmission is small, and the accuracy of sound collection can reach about 80% - 98%. Therefore, the preferred value range of S3 / S is: 2.5 ≤ S3 / S ≤ 13.5. On this basis, considering that when the value range of S3 / S is 7 < S3 / S ≤ 13.5, the accuracy of sound collection decreases, generally between 80% and 90%, but the size of the windproof sound-permeable member increases instead. Although it will not significantly cause a large loss of the target noise during transmission and can basically meet the requirements of active noise reduction for sound collection, since it increases the overall size of the protection device and occupies the installation space in the air duct, the more preferred value range of S3 / S is: 2.5 ≤ S3 / S ≤ 7.

[0011] As an improvement, the above-mentioned sound collection device is arranged in the air duct of the oil fume suction device. The second channel section is arranged along the extension direction of the air duct, and the second sound inlet is formed at the end of the housing facing away from the wind. The opening direction of the second sound inlet is the same as the extension direction of the air duct.

[0012] The above-mentioned "end part of the housing facing away from the wind" can be understood as: along the extension direction of the air duct, the end of the housing adjacent to the fan system of the range hood.

[0013] The above-mentioned "the second channel section is arranged along the extension direction of the air duct" can be understood as that the overall extension direction of the second channel section is the same as or parallel to the extension direction of the air duct, or it can also be understood that the overall extension direction of the second channel section has a certain inclination angle (such as an inclination angle of 0-30°) relative to the extension direction of the air duct.

[0014] The second channel section can be a straight channel structure or a non-straight channel structure with local bends or curves. In order to avoid adverse effects on sound propagation due to excessive turns in the sound propagation path within the sound collection device, and considering the convenience of installing components such as the windproof sound transmission element in the second channel section, the main body of the second channel section will adopt a straight channel consistent with the extension direction of the air duct. Generally speaking, in order to minimize the contamination of the sound collection element in the first channel section by oil fumes, the orientation of the first sound inlet should be avoided to be the same as the extension direction of the second channel section, that is, the opening direction of the first sound inlet and the extension direction of the second channel section should 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. 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 liquid will still enter the first channel section through the first sound inlet to 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, preferably, the value range of the first angle formed by the intersection of the opening direction of the first sound inlet and the extension direction of the second channel section is: 5°≤M≤180°.

[0015] For better avoiding the contact of the sound collection element with oil fumes and considering the improvement of the windproof effect, both the second channel section and the extension direction of the air duct extend vertically, the opening of the second sound inlet faces upward, and the opening direction of the first sound inlet is perpendicular to the extension direction of the sound collection channel, that is, the first angle is a right angle.

[0016] 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 preferably adopts a split structure design assembled together by fasteners. Specifically, the housing includes a mounting frame and a windproof cover. 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 windproof cover covers outside the mounting frame and defines a sound collection channel between the windproof cover and the mounting frame, which is connected to the first sound inlet of the receiving groove and is located in front of the receiving groove. The sound collection channel constitutes the second channel section.

[0017] As an improvement, the front side wall of the windproof sound-permeable member is attached to the rear side wall of the windproof cover. With the above structural design, the windproof sound-permeable member can be in a compressed state. By compression, the material density can be increased, which can effectively reduce the possibility of the penetration of the air flow pressure pulsation, thereby further improving the windproof effect.

[0018] As an improvement, the second channel section extends vertically. The windproof sound-permeable member includes an extension section extending from the top edge of the first sound inlet of the receiving groove towards the position where the second sound inlet is located. The length of the extension section of the windproof sound-permeable member is denoted as h, and the size of the first sound inlet of the receiving groove in the up-down direction is m. Among them, the value range of h / m is: 0.125 - 0.6. If the value of h / m is too small (such as less than 0.125), it means that the upward extension length of the windproof sound-permeable member is small and is not enough to offset the influence of the air flow pulsation pressure, resulting in a poor windproof effect. If the value of h / m is too large (such as greater than 0.6), it means that the upward extension length of the windproof sound-permeable member is large. Although the windproof requirement is met, it will have an adverse impact on sound propagation, that is, a part of the sound pressure will be lost, resulting in not enough noise passing through the sound collection channel of the protection device and reaching the receiving groove, making it difficult to meet the sound pressure requirement of the sound collection element and affecting the accuracy of noise collection.

[0019] To ensure the windproof effect, the thickness of the windproof sound-permeable component (i.e., the dimension in the front-back direction) needs to be reasonably designed. At the same time, to reduce the impact of the windproof sound-permeable component on the sound propagation loss, the dimension of the part of the windproof sound-permeable component adjacent to the second sound inlet in the left-right direction also needs to be reasonably designed. The dimension of the part of the main body of the windproof sound-permeable component adjacent to the second sound inlet in the front-back direction is denoted as e, and the value range of e is 40mm ≥ e ≥ 3mm. Among them, to ensure that the windproof sound-permeable component can effectively prevent the airflow in the air duct from directly impacting the sound collection element, the dimension of the windproof sound-permeable component in the front-back direction (i.e., the thickness) needs to be e ≥ 3mm. Of course, considering that the windproof ball (generally made of porous materials that can prevent airflow disturbance and transmit sound) will have an adverse impact on sound attenuation, the dimension of the windproof sound-permeable component in the front-back direction (i.e., the thickness) cannot be too large, and e ≤ 40mm is required.

[0020] With the increase in the dimension of the windproof sound-permeable component in the up-down direction, the windproof effect increases, but it also means an increase in the loss during the propagation of sound in the protection device. Therefore, on the basis that the dimension of the windproof sound-permeable component in the up-down direction meets the conditions, the sound-permeable area of the windproof sound-permeable component should be adapted to the dimension range of the windproof sound-permeable component in the up-down direction to ensure that enough noise to be collected enters the sound collection channel, thereby further reducing the impact of the windproof sound-permeable component on the sound propagation loss. Specifically, the cross-sectional area of the main body of the windproof sound-permeable component adjacent to the second sound inlet is S2, the dimension of the part of the windproof sound-permeable component adjacent to the second sound inlet in the front-back direction is denoted as e, the dimension of the main body of the windproof sound-permeable component in the up-down direction is denoted as g, and g / 2 + e / 2 represents the sound propagation path length in the windproof sound-permeable component. When the propagation path is longer, the sound loss is more. According to the sound propagation principle L w =L1 + 10lgS (L W(where L1 is the sound power, S is the area at the sound entrance) Due to sound loss, the sound pressure decreases during sound propagation. As compensation, S2 should be increased to ensure that enough sound is collected by the sound collection element. Therefore, considering the sound propagation loss and compensation, the value of S2 / (g / 2+e / 2) should be greater than 8mm, and the preferred value range is: 10≤2S2 / (g+e)≤15. Among them, if S2 / (g / 2+e / 2) is too small, such as S2 / (g / 2+e / 2)≤8, it means that the entrance area of the windproof and sound-permeable component at the end position adjacent to the second sound entrance for effective sound transmission from top to bottom is small, and the amount of sound entering is insufficient to offset the adverse effect of the windproof and sound-permeable component on sound loss in the vertical direction, thereby reducing the accuracy of the sound collection by the sound collection element. If S2 / (g / 2+e / 2) is too large, such as S2 / (g / 2+e / 2)≥15, it means that the entrance area of the windproof and sound-permeable component at the end position adjacent to the second sound entrance for effective transmission of sound from top to bottom is large. Similarly, the area of the upper part of the windproof and sound-permeable component that contacts oil stains increases, affecting the service life of the windproof and sound-permeable component.

[0021] A further improvement is that the windproof and sound-permeable member is made of a porous sound-absorbing material. Using a damping material such as a porous sound-absorbing material as a windproof and sound-permeable member can slow down airflow, eliminate airflow impact, and ensure that the collected sound can pass through. Specifically, polyurethane foam, melamine foam, or the like can be used for the windproof and sound-permeable member. This windproof and sound-permeable member prevents airflow from impacting the oil-proof sound-permeable membrane and generating additional noise. Furthermore, the porous nature of the material absorbs high-frequency components of sound energy, thereby filtering out noise signals.

[0022] Generally speaking, there can be a gap between the rear sidewall of the windshield located in front of the windproof and sound-permeable member and the front sidewall of the windproof and sound-permeable member, or the two can be designed to fit together. Preferably, the rear sidewall of the windshield located in front of the windproof and sound-permeable member fits together with the front sidewall of the windproof and sound-permeable member. The above structural design can compress the windproof and sound-permeable member, which increases the material density and effectively reduces the possibility of airflow pressure pulsation penetrating, thereby further improving the windproof effect.

[0023] In order to improve the protective effect of the windproof cover on the windproof and sound-permeable component and reduce the contact between the windproof and sound-permeable component and the smoke in the air duct as much as possible, the edge part of the windproof cover corresponding to the position of the second sound inlet has a sixth distance in the front-to-back direction along the direction of airflow in the air duct. In order to avoid the contact between the oil-proof sound-permeable membrane and the windproof and sound-permeable component and affect the sound transmission effect here, the windproof and sound-permeable component and the oil-proof sound-permeable membrane have a sixth distance in the front-to-back direction.

[0024] In order to further improve the oil-proof effect and prevent the sound collection element from being contaminated by oil stains, an oil-proof sound-transmitting membrane that shields the front side of the sound collection element is also provided at the first sound inlet in the accommodation groove. There is a fourth spacing between the oil-proof sound-transmitting membrane and the sound collection element, and this fourth spacing is denoted as f. Among them, the value range of f is: f≥2mm.

[0025] While the above protection device realizes the suppression of wind noise by the sound collection element, it also needs to ensure that the noise signal passes through. Since the structural design of the protection device forms a semi-closed cavity, that is, it will itself form a low-pass filter. Therefore, it is necessary to make the cut-off frequency f of the structure itself c greater than the upper frequency limit f of the active noise reduction concerned a in order to accurately collect all the original noise frequencies concerned by the active noise reduction. Specifically, the corresponding structural design parameters of the protection device must meet the following conditions: The cross-sectional area of the sound collection channel near the second sound inlet is denoted as S0, the volume of the inner cavity formed by the oil-proof sound-transmitting membrane and the inner wall of the accommodation groove is denoted as V, the dimension of the main body of the wind-proof sound-transmitting member in the front-rear direction is denoted as e, and the dimension of the wind-proof sound-transmitting member in the up-down direction is denoted as g. Among them:

[0026] The technical solution adopted by the present invention to solve the second technical problem is: An oil fume extractor includes a flue for flue gas to pass through and a sound collection device provided in the flue, and the sound collection device adopts the above-mentioned sound collection device.

[0027] As an improvement, the sound collection element is a microphone.

[0028] Compared with the prior art, the advantages of the present invention are: The sound collection element is installed in the first channel section of the housing, and a wind-proof sound-transmitting member is provided in the second channel section of the housing. Therefore, it can effectively avoid the interference of the airflow on the sound collection element, effectively eliminate wind noise, and prevent the sound collection element from being contaminated by oil stains. On the other hand, since a wind-proof sound-transmitting member is provided in the sound collection channel, it will have an adverse effect on the sound propagation, that is, a part of the sound pressure will be lost. According to the sound propagation principle L w =L1 + 10lgS (L Wis sound power, L1 is sound pressure, and S is the area at the sound entrance) It can be seen that the size of the windproof and sound-permeable component cannot be designed to be too large, otherwise the loss of sound pressure L1 will increase due to the excessive size design of the windproof and sound-permeable component. On the other hand, when the sound pressure is lost, as compensation, the opening area S at the first sound entrance of the first channel section can also be used to maintain the sound power. Of course, in order to ensure the windproof performance of the windproof and sound-permeable component and ensure that the airflow pressure pulsation does not affect the sound collecting components, the size of the windproof and sound-permeable component cannot be designed to be too small. For this reason, the value of S3 / S needs to be reasonably designed: 13.5≥S3 / S≥1.5. When S3 / S is too small (such as less than 1.5), it means that the size of the windproof and sound-permeable component is small, and the area of the first sound entrance is too large, resulting in poor windproof effect, which will affect the accuracy of sound collection; when S3 / S is too large (such as greater than 13.5), it means that the size of the windproof and sound-permeable component is large, and the area of the first sound entrance is too small, which will cause more sound loss when passing through the windproof and sound-permeable component, and it will be difficult for the sound to meet the sound pressure requirements of the sound collection component when it propagates to the accommodating groove. In this application, the ratio of the area S3 of the cross section formed by the windproof and sound-permeable component in the extension direction of the second channel segment to the opening area S at the first sound entrance at the front of the first channel segment needs to be limited to a reasonable value range (13.5≥S3 / S≥1.5). On the basis of ensuring that the windproof and sound-permeable component has a relatively good windproof effect, it avoids the sound loss caused by the excessive size of the windproof and sound-permeable component when passing through the windproof and sound-permeable component, so that the sound can meet the sound pressure requirements of the sound collection component when it propagates to the first channel segment, thereby improving the accuracy of noise collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the three-dimensional structure of the protective device according to Example 1 of the present invention;

[0030] Figure 2 This is an exploded view of the protective device of Example 1 of the present invention;

[0031] Figure 3 A vertical cross-sectional view of a protective device according to embodiment 1 of the present invention;

[0032] Figure 4 for Figure 3 The middle diagram is a structural diagram after omitting the windproof and sound-permeable components;

[0033] Figure 5 For the Figure 3 Cross-sectional view cut along the AA direction;

[0034] Figure 6 This is a schematic diagram of the three-dimensional structure of the protective device of Example 1 of the present invention installed in the air duct;

[0035] Figure 7 for Figure 6a transverse cross-sectional view cut along the anterior-posterior direction;

[0036] Figure 8 Schematic diagram of the sound propagation process at the first sound inlet of the mounting frame;

[0037] Figure 9 A vertical cross-sectional view of a protective device according to embodiment 2 of the present invention;

[0038] Figure 10 for Figure 9 The middle diagram is a structural diagram after omitting the windproof and sound-permeable components;

[0039] Figure 11 This is a vertical cross-sectional view of the protective device of Example 3 of the present invention (the mounting frame does not have a hanging edge);

[0040] Figure 12 for Figure 11 The middle diagram is a structural diagram after omitting the windproof and sound-permeable components;

[0041] Figure 13 A vertical cross-sectional view of another structure of the protective device of Example 3 of the present invention (with a hanging retaining edge on the mounting frame);

[0042] Figure 14 for Figure 13 The middle diagram is a structural diagram after omitting the windproof and sound-permeable components;

[0043] Figure 15 A vertical cross-sectional view of a protective device according to embodiment 4 of the present invention;

[0044] Figure 16 for Figure 15 The middle diagram is a structural diagram after omitting the windproof and sound-permeable components;

[0045] Figure 17 A vertical cross-sectional view of a protective device according to embodiment 5 of the present invention;

[0046] Figure 18 for Figure 17 The schematic diagram of the structure after omitting the windproof and sound-permeable parts. DETAILED DESCRIPTION

[0047] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0048] In the description and claims of the present invention, 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 invention. However, these terms are used herein only for the purpose of convenience of description and are determined based on the exemplary orientations shown in the drawings. Since the embodiments disclosed in the present invention 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 directions opposite to or consistent with the direction of gravity.

[0049] Embodiment 1

[0050] Figures 1 - 7 A preferred embodiment of the sound collection device and the range hood of the present invention is shown.

[0051] 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 section and a second channel section connected in sequence. Among them, 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 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 section and the second channel section are straight-line channels. Among them, 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 connection line between the position where the sound inlet of this channel section is located and the position where the sound collection element 11 is located. The extension line of the second channel section can be understood as the connection line between the position where the sound inlet of this channel section is located and the position where the sound outlet is located.

[0052] 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.

[0053] 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 frame 20 and a wind-proof cover 40.

[0054] In this embodiment, taking the box 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 1 serves as the air duct 10. The mounting frame 20 is installed in the air duct 10 and can be specifically installed on the rear side wall of the air duct 10. A receiving groove 21 is formed on the front side wall of the mounting frame 20, and this receiving groove constitutes the first channel section of the above-mentioned housing 2. The sound collection element 11 is placed in the receiving groove 21. 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 through which the external sound (the sound collection channel in this embodiment) can enter the receiving groove 21 and be effectively collected by the sound collection element 11, 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, rather than the largest open mouth at the front part of the receiving groove 21. In the state where the mounting frame 20 is installed in place on the rear side wall of the air duct 10, the rear wall of the part of the mounting frame 20 where the receiving groove 21 is located is in contact with the 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. For this reason, components such as the mounting frame 20, the wind-proof sound-permeable member 30, and the wind-proof cover 40 are also correspondingly provided with two or more.

[0055] The mounting bracket 20 further has a third mounting portion 263 extending respectively to the left and right sides and exposing outside the wind shield 40, and a fourth mounting portion 264 extending downward at the bottom of the mounting bracket 20 and exposing outside the wind shield 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 extending forward. The wind shield 40 can be connected to the connecting post 265 of the mounting bracket 20 by screws 50.

[0056] The wind shield 40 includes a first side wall 411 and a second side wall 412 that are opposite to each other left and right and arranged at intervals, and a third side wall 413 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 shield 40 is located on the front side of the receiving groove 21 of the mounting bracket 20. On the third side wall 413 of the wind shield 40, there is a guiding surface 4130 that gradually inclines towards the inside of the air duct 10 along the direction of the airflow in the air duct 10 (such as Figure 3 the direction indicated by the hollow arrow in the figure). 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. 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 direction of the airflow in the air duct 10, the position where the guiding surface 4130 of the wind shield 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 shield 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 shield 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 flow of the airflow 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 shield 40 needs to be reasonably designed. The included angle formed between the guiding surface 4130 of the wind shield 40 and the side wall of the air duct 10 for mounting the wind shield 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 protection 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 shield 40 protrudes forward relative to the side wall of the air duct 10 for mounting the wind shield 40 is denoted as b. Considering that if the distance that the wind shield 40 protrudes 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 airflow at the position of the protection 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 .

[0057] To improve the anti-oil pollution effect, the wind shield 40 of this embodiment can be made of plastic or metal parts.

[0058] The wind shield 40 of this embodiment and the mounting frame 20 have a clearance channel extending vertically in the front-rear direction. The upper end (i.e., the end close to the noise source) of this clearance channel is open, and the lower end (i.e., the end far from the noise source) is closed, which is the sound collection channel 200. This 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 portion 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 air duct 10 of this embodiment also extends 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 of the sound collection channel 200 to form a first included angle M. The value range of this first included angle M is: 5° ≤ M ≤ 180°. Considering that if the included angle formed between the opening direction B1 of the first sound inlet 211 and the extension direction of the sound collection channel 200 is too small, the oil liquid will still enter the accommodation groove 21 through the first sound inlet 211 to contaminate the sound collection element 11. If the included angle formed between the opening direction 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 turns 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 angle of the first included angle formed between the opening direction of the first sound inlet 211 and the extension direction B3 of the sound collection channel 200 also needs to be reasonably designed. Preferably, the value of the first included angle M is 90°. In addition, the opening direction B4 of the second sound inlet 45 of this embodiment faces upward, that is, the opening direction of the second sound inlet 45 is also perpendicular to the opening direction B1 of the first sound inlet 211.

[0059] The sound collection channel 200 is located at the front side of the accommodation groove 21 of the mounting bracket 20. The lower part of the sound collection channel 200 is opposite to the first sound inlet 211 at the front part 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-permeable member 30, greatly reducing the pollution of the oil fume to the windproof sound-permeable 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 reserved, directly isolating the airflow noise at the lower part and the noise interference of the secondary turbulent flow, so that the noise entering the windproof sound-permeable 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-permeable member 30 and minimize the contact between the windproof sound-permeable member 30 and the flue gas in the air duct, an extension wall 46 is provided at the upper edge of the wind shield 40 extending upward relative to the top surface of the windproof sound-permeable member 30, that is, the top edge of the extension wall 46 is higher than the top surface of the windproof sound-permeable 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 sound entering the second sound inlet 45.

[0060] Since the sound collection element 11 is installed in the accommodation 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 element 30 is provided in the sound collection channel 200, effectively eliminating 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 element 30, thereby reducing the impact on the accuracy of the microphone sound collection. 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, arranging the sound collection channel 200 along the extension direction of the air duct can make the second sound inlet 45 of the sound collection channel 200 face the sound source so as to directly receive the noise. On the other hand, considering that a windproof and sound-permeable element 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 the sound collection, in this embodiment, the sound collection channel 200 for placing the windproof and sound-permeable element 30 is arranged in the extension direction of the air duct 10, and the sound propagation path has a turning design, so that the size of the entire protection 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 of the protection device 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. On this basis, considering that the air duct environment of the range hood is full of oil stains, if the orientation of the first sound inlet 211 is consistent with the extension direction of the sound collection channel, then the sound collection element 11 is easily contaminated by the oil stains flowing down along the air duct 10. Therefore, in this embodiment, a structural design is adopted in which the sound collection channel 200 is located on the front side of the accommodation groove 21, that is, the opening orientation B1 of the first sound inlet 211 of the accommodation groove 21 has a certain included angle with the extension direction of the sound collection channel 200. This makes the path for the noise in the air duct 10 to propagate from the second sound inlet 45 to the position of the sound collection element 11 in the accommodation groove 21 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 stains adhere to the side wall of the sound collection channel 200 or the windproof and sound-permeable element 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.Considering that the target noise to be collected by the active noise cancellation system (mainly from the fan system) is low-frequency noise, the sound propagation path inside the protective device adopts a turning path design, which has a weakening effect on high-frequency sounds (such as the high-frequency sound components in 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 inside the protective device, facilitating 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 pipeline, due to its longer wavelength, it is not easily blocked and reflected by the pipeline, so it can better propagate and spread. While the wavelength of high-frequency noise is shorter, it is easily reflected and absorbed by the shape and bending of the pipeline, so it is more difficult to propagate and spread in the pipeline compared to low-frequency noise.

[0061] The oil-proof sound-permeable membrane 28 covers the first sound inlet 211 of the receiving groove 21 of the mounting bracket 20, specifically installed at the position of the front open edge of the receiving groove 21 of the mounting bracket 20. More specifically, in order to facilitate the installation of the oil-proof sound-permeable membrane 28 and ensure the sealing of its installation opening, an annular step portion 210 is formed at the edge position of the receiving groove 21 at its first sound inlet 211, and the oil-proof sound-permeable membrane 28 is provided on this annular step portion 210. In order to ensure the oil-proof performance of the oil-proof sound-permeable membrane 28 and enable it to effectively transmit sound waves, the oil-proof sound-permeable membrane 28 of this embodiment is preferably a polyethylene film. Among them, as Figure 3 shown, there is a fourth distance between the oil-proof sound-permeable membrane 28 and the sound collection element 11, which is denoted as f. Among them, the value range of f is: f≥2mm. Thus, it is avoided that the film vibrates or undergoes micro-deformation and contacts the sound collection element 11, resulting in sound propagation variation and affecting the accuracy of sound collection. It can be understood that the above-mentioned fourth distance f between the oil-proof sound-permeable membrane 28 and the sound collection element 11 should refer to the distance between the oil-proof sound-permeable membrane 28 and the microphone chip on the sound collection element 28, that is, the oil-proof sound-permeable membrane 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. The wind-proof sound-permeable member 30 does not directly contact the oil-proof sound-permeable membrane 28 to ensure the oil-proof effect. Specifically, there is a sixth distance between the oil-proof sound-permeable membrane 28 and the main body of the wind-proof sound-permeable member 30 in the front-rear direction, which is denoted as n. The sixth distance n between the oil-proof sound-permeable membrane 28 and the wind-proof sound-permeable member 30 should be greater than 0.1mm, and the preferred range is 0.5mm - 3mm.

[0062] In order to effectively slow down the airflow and eliminate the airflow impact, the windproof sound-permeable member 30 is a sleeve member made of porous sound-absorbing material. For example, the windproof sound-permeable member 30 can be made of polyurethane foam, melamine foam sponge, etc. Among them, the porosity of the windproof sound-permeable member 30 is greater than 70%. The windproof sound-permeable member 30 of this embodiment can not only prevent the airflow from impacting the oil-proof sound-permeable film 28 and generating additional noise, but also, due to the property of its porous material itself, can absorb the high-frequency components in the sound energy, realizing the filtering function of filtering the noise signal. Specifically, the front side wall of the windproof sound-permeable member 30 is attached to the rear side wall of the third side wall 413 of the windproof cover 40, so that the windproof sound-permeable 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 windproof effect.

[0063] Due to the setting of the windproof sound-permeable member 30 in the sound collection 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 collection 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 the noise to be collected enters the accommodation groove 21 of the mounting frame 20 to be received by the sound collection element 11 and achieve the purpose of accurately collecting the noise signal. Specifically, the principle of sound attenuation and compensation is as follows:

[0064] L w = L1 - ΔL + 10lgS0

[0065] Among them, the noise energy that the sound collection component can collect per unit time is the sound power L w ;

[0066] The sound pressure when the sound reaches the top surface of the windproof sound-permeable member 30 is L1;

[0067] Due to the attenuation effect of the windproof sound-permeable member 30, the lost noise sound pressure is ΔL;

[0068] The cross-sectional area S0 of the second sound inlet 45 of the sound collection channel 200;

[0069] 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 the sound power L collected by the sound collection element can be ensured by increasing S0 wIt will not become smaller, ensuring the accuracy of sound collection. Specifically, the ratio of the area S0 of the cross-section at the second sound inlet 45 of the sound collection channel 200 in this embodiment to the opening area S at the first sound inlet 211 at the front part of the accommodation groove needs to be reasonably limited. Among them, S0 / S≥0.18. Thus, it can be ensured that enough noise can pass through the sound collection channel 200 of the protection device to compensate for the sound pressure loss caused by the setting of the windproof sound-permeable member, and further ensure that the sound can meet the sound pressure requirements of the sound collection element 11 when propagating to the accommodation groove 21, further improving the accuracy of noise collection.

[0070] 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 part of the accommodation groove and ensure the windproof effect, the cross-sectional area of the main body of the windproof sound-permeable member 30 near the second sound inlet 45 is S2. As shown in Figure 3 the cross-section cut along the S2 - S2 direction is the cross-sectional area of the main body of the windproof sound-permeable member 30 near the second sound inlet 45. g / 2 + e / 2 represents the sound propagation path length in the windproof sound-permeable member. When the propagation path is long, more sound is lost. According to the sound propagation principle L w =L1 + 10lgS (where L W is the sound power, L1 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 the sound propagation process. As a compensation, S2 should be increased at this time to ensure that enough sound is collected by the sound collection element. Therefore, considering the sound propagation loss and compensation, the value of S2 / (g / 2 + e / 2) should be greater than 8 mm, and the preferred value range is: 10≤2S2 / (g + e)≤15. If S2 / (g / 2 + e / 2) is too small, such as S2 / (g / 2 + e / 2)≤8, it means that the inlet area for the sound to effectively pass from top to bottom at the end position of the windproof sound-permeable member near the second sound inlet is small, and the amount of incoming sound is not enough to balance the adverse effects of the windproof sound-permeable member 30 on sound loss in the up and down directions and front and back directions, reducing the accuracy of the sound collection by the sound collection element 11. If S2 / (g / 2 + e / 2) is too large, such as S2 / (g / 2 + e / + e)≥15, it means that the inlet area for the sound to effectively pass from top to bottom at the end position of the windproof sound-permeable member 30 near 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 increases, affecting the service life of the windproof sound-permeable member 30. The windproof sound-permeable member 30 in this embodiment is filled in the sound collection channel 200, that is, the cross-sectional area S2 of the main body of the windproof sound-permeable member 30 near the second sound inlet 45 is basically the same as the cross-sectional area S0 of the second sound inlet 45 of the sound collection channel 200.

[0071] The area of the cross section of the windproof and sound-permeable member 30 of this embodiment cut along the extension direction of the sound collecting channel 200 (i.e., the cross section cut vertically along the left and right directions) is recorded as S3. Figure 5 The cross section along the S3-S3 direction is the cross section of the main body of the windproof sound-permeable member 30 cut along the extension direction of the sound collection channel 200. The opening area of the first sound inlet 211 at the front of the receiving slot 21 of the mounting frame 20 is denoted as S, where S 3 / The value range of S is: S3 / S≥1.5. Since the windproof and sound-permeable member 30 is provided in the sound collection channel 200, it will have an adverse effect on sound propagation, that is, it will lose some sound pressure. Therefore, the size of the windproof and sound-permeable member 30 cannot be designed to be too large. Of course, in order to ensure the windproof performance of the windproof and sound-permeable member 30 and ensure that the airflow pressure pulsation does not affect the sound collection element 11, the size of the windproof and sound-permeable member 30 cannot be designed to be too small. Therefore, on the basis of ensuring that the windproof and sound-permeable member 30 covers the first sound inlet 211 of the receiving groove 21, the windproof and sound-permeable member 30 is extended in the sound collection channel. The ratio of the area S3 of the cross section formed by cutting in the extending direction to the opening area S at the first sound inlet 211 at the front of the receiving groove 21 needs to be limited to a reasonable value range (S3 / S≥1.5). In this way, it can ensure that the windproof and sound-permeable component 30 has a relatively good windproof effect, while avoiding the large size of the windproof and sound-permeable component 30, which causes a large loss of sound when passing through the windproof and sound-permeable component 30, so that the sound can meet the sound pressure requirements of the sound collecting element 11 when propagating to the receiving groove, thereby improving the accuracy of noise collection.

[0072] When S3 / S < 1.5, the size of the windproof sound-permeable member 30 is too small, and the protection of the first sound inlet 211 is insufficient, resulting in its being affected by the airflow pressure pulsation; the accuracy of sound collection is poor, less than 75%, and the collected noise is generally higher than the original noise. When S3 / S > 13.5, since the windproof sound-permeable member 30 is too large, it causes more attenuation to the sound, making the accuracy less than 80%. At this time, the collected noise is generally less than the original noise, so it is not recommended to use either. Specifically, when the value range of S3 / S is 1.5 ≤ S3 / S < 2.5, at this time, the windproof effect of the windproof sound-permeable member 30 will be significantly enhanced, and the accuracy of sound collection can reach about 80%. When the value range of S3 / S is 2.5 ≤ S3 / S ≤ 13.5, the windproof effect of the windproof sound-permeable member 30 is relatively excellent, the target noise has little loss during transmission, and the accuracy of sound collection can reach about 80% - 98%. Therefore, the preferred value range of S3 / S is: 2.5 ≤ S3 / S ≤ 13.5. On this basis, considering that when the value range of S3 / S is 7 < S3 / S ≤ 13.5, the accuracy of sound collection decreases, generally between 80% and 90%. However, the size of the windproof sound-permeable member 30 increases instead. Although it will not significantly cause large losses to the target noise during transmission and can basically meet the requirements for sound collection in active noise reduction, since it increases the overall size of the protection device and occupies the installation space in the air duct, the more preferred value range of S3 / S is: 2.5 ≤ S3 / S ≤ 7.

[0073] The above-mentioned sound collection accuracy mainly refers to the degree of conformity between the noise collected by the microphone and the original noise. The specific calculation method is as follows: The collection accuracy S is the average value of the accuracy S i in the selected noise frequency range at different one-third octave center frequency bands.

[0074]

[0075] Where: n is the number of center octaves in the frequency range of concern:

[0076] The accuracy S i in a certain center frequency band is calculated as follows:

[0077]

[0078] Where: the sound pressure value L of the collected noise at this center frequency ic ;

[0079] the sound pressure value L of the original noise at this center frequency iy ;

[0080] The cross section of the windproof and sound-permeable member 30 of this embodiment cut along the extension direction of the sound collecting channel 200 is rectangular, so S3 = d1*g.

[0081] The windproof and sound-permeable component 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, and the length of the extension section 301 of the windproof and sound-permeable component 30 is recorded as h, and the dimension of the first sound inlet 211 of the accommodating groove 21 in the up and down directions is m, wherein 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 front to back, that is, there is a turning portion at the first sound inlet 211 of the receiving groove 21, if the extension length of the outer peripheral edge portion of the windproof and sound-permeable member 30 relative to the edge of the first sound inlet 211 of the receiving groove 21 is too short (for example, h / m is less than 0.125), it will also be greatly affected by wind noise. Therefore, after the above parameter design, the windproof effect of the windproof and sound-permeable member is effectively guaranteed, and the impact on the accuracy of sound collection caused by the excessively short extension length of the outer peripheral edge of the windproof and sound-permeable member is avoided. Of course, considering the adverse effect of the windproof and sound-permeable member 30 on sound attenuation, the length of the extension section 301 of the windproof and sound-permeable member 30 should not be too large. If h / m is greater than 0.6, the sound will not be able to effectively meet the sound pressure requirements of the sound collection element 11 when it propagates to the receiving groove 21, thereby reducing the accuracy of noise collection.

[0082] To avoid the windproof and sound-permeable component 30 from contacting the oil continuously flowing down on the side wall of the air duct 10, after being installed on the mounting bracket 20, there is a first spacing between the windproof and sound-permeable component 30 and the rear side wall of the air duct 10, which is denoted as d. Among them, the value range of d is: d≥4mm. Similarly, to ensure the windproof effect, the dimension (i.e., thickness) of the main body of the windproof and sound-permeable component 30 in the front-rear direction is denoted as e. Among them, the value range of e is: 40mm≥e≥3mm. Specifically, when e≥3mm, it can ensure that the windproof and sound-permeable component 30 can effectively prevent the airflow 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 airflow disturbance and transmit sound) on sound attenuation, the dimension (i.e., thickness) of the windproof and sound-permeable component 30 in the front-rear direction cannot be too large, and e≤40mm is required. At the same time, when the dimension (i.e., thickness) of the windproof and sound-permeable component 30 in the front-rear direction is fixed, the dimension d1 of the main body of the windproof and sound-permeable component 30 in the left-right direction also needs to be adapted to it, that is, it is necessary to reasonably limit e / d1. Specifically, if e / d1 is too small, it means that the dimension of the main body of the windproof and sound-permeable component 30 in the left-right direction 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 and sound-permeable component 30. If e / d1 is too small, it means that the dimension of the main body of the windproof and sound-permeable component 30 in the left-right direction is small, which is not conducive to the sound being transmitted into the sound collection channel 200 from a large angular range in the horizontal direction above, affecting the accuracy of sound collection.

[0083] While the protection structure of this embodiment realizes the suppression of wind noise of 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 acoustic mass M a and acoustic 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 reduction, so as to accurately collect all the original noise frequencies concerned by active noise reduction.

[0084] Among them:

[0085]

[0086] V is the volume of the cavity in the protection structure, specifically the volume of the inner cavity surrounded by the oil-proof and sound-permeable membrane and the inner wall of the receiving groove of the mounting bracket; ρ0 is the air density; c0 is the speed of sound in air, 343m / s; L is the sound propagation path length;

[0087] S0 is the effective area of the pipeline sound propagation, which can be simply taken as the minimum cross-sectional area of the pipeline during the sound propagation process. In this embodiment, S0 is the cross-sectional area of the second sound inlet 45 of the sound collection channel 200;

[0088]

[0089] The applicant's research found that due to the structural limitations of the range hood and the noise source and its propagation characteristics, the upper frequency limit f of the active noise reduction concern for the range hood a , should be 1200 - 2000 Hz. Therefore, it can be obtained that:

[0090]

[0091] After simplification, it is:

[0092]

[0093] The protection structure of this embodiment must meet the requirements of the above formula.

[0094] 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. Among them, the second sound inlet 45 is a strip-shaped opening. Therefore:

[0095] S0 = ed;

[0096] L is the path length of sound propagation. Since the sound collection channel 200 in this embodiment is not a regular pipeline, it can be simplified as:

[0097]

[0098] Among them, the size of the windproof and sound-permeable part in the up and down direction is denoted as g, and the size (i.e., thickness) of the main body of the windproof and sound-permeable part 30 in the front and back direction is denoted as e.

[0099] The above-mentioned

[0100] After further simplification, it is:

[0101]

[0102] In this embodiment, after the sound collection element 11 is installed in the receiving slot 21 of the mounting frame 20, an oil-proof sound-permeable membrane 28 is installed at the first sound inlet 211 thereof. A windproof sound-permeable member 30 is installed outside the first sound inlet 211, and a windshield 40 is installed outside the windproof sound-permeable member 30. This protective device utilizes these three layers of protection to effectively eliminate wind noise and prevent oil contamination. After the windshield 40 covers the windproof sound-permeable member 30, a second sound inlet 45 is reserved at the leeward end, communicating with the outside world. Due to airflow patterns, the flow near the windproof sound-permeable member 30 near the second sound inlet 45 is a low-speed, high-static-pressure region, effectively reducing the adhesion of oil smoke to the windproof sound-permeable member 30. Furthermore, this allows noise to be effectively transmitted through the second sound inlet 45 to the receiving slot 21 of the mounting frame 20, ensuring the accuracy of noise data collection. On the other hand, considering the impact of the windproof and sound-permeable component 30 and the windproof cover 40 on the obstruction and loss of sound propagation, the ratio of the opening area S at the first sound entrance 211 of the accommodating groove 21 to the opening area S0 at the second sound entrance 45 of the sound collection channel 200 is limited within a reasonable value range, which can ensure that enough noise passes through the protective device and is received by the sound collection element, thereby improving the accuracy of noise collection. Furthermore, on the basis of ensuring that the windproof and sound-permeable component 30 covers the first sound inlet 211 of the receiving groove 21, the ratio of the area S3 of the cross section formed by the windproof and sound-permeable component 30 in the extension direction of the sound collection channel 200 to the opening area S at the first sound inlet 211 at the front of the receiving groove 21 needs to be limited to a reasonable value range (13.5≥S3 / S≥1.5). In this way, it can ensure that the windproof and sound-permeable component 30 has a relatively good windproof effect, thereby avoiding the large loss of sound when passing through the windproof and sound-permeable component 30 due to the excessive size of the windproof and sound-permeable component 30, so that the sound can meet the sound pressure requirement of the sound collection element 11 when it propagates to the receiving groove 21, thereby further improving the accuracy of noise collection. If S3 / S is too small (such as less than 1.5), it means that the size of the windproof and sound-permeable component 30 is small, and the area of the first sound inlet 211 of the receiving groove 21 is too large, the windproof effect is poor, and the accuracy of sound collection is affected; if S3 / S is too large (such as greater than 13.5), it means that the size of the windproof and sound-permeable component 30 is large, and the area of the first sound inlet 211 of the receiving groove 21 is too small, which will cause more sound loss when passing through the windproof and sound-permeable component 30, and it will be difficult for the sound to meet the sound pressure requirements of the sound collection element 11 when the sound is transmitted to the receiving groove 211.

[0103] This embodiment also relates to a range hood, comprising an air duct 10 for smoke to pass through and an active noise reduction system provided in the air duct 10, wherein the active noise reduction system comprises the above-mentioned sound collection device.

[0104] Example 2

[0105] Figure 9 and Figure 10 Another preferred embodiment of the sound collection device and range hood of the present invention is shown. This embodiment differs from the first embodiment in that the entire sound collection channel 200 is a vertically extending linear channel. The sound collection channel 200 has a certain inclination angle relative to the vertical direction. Specifically, the opening direction of the first sound inlet 211 of the receiving slot 21 of the mounting frame 20 is horizontal. The sound collection channel 200 is inclined from top to bottom toward the location of the receiving slot 21 of the mounting frame 20. The first angle M formed between the direction of the first sound inlet 211 and the extension direction of the sound collection channel 200 is an acute angle, with a value range of 5°≤M<90°. Preferably, the value range of the first angle M is 30°≤M≤80°, wherein the magnitude of the first angle M is consistent with the deflection angle of the path during sound propagation. Figure 9 It can be seen that the propagation path of the sound in the protective device of this embodiment is a turning path, such as Figure 9 The turning path S is shown in FIG. Since the turning angle of the sound propagation path of this embodiment is relatively gentle compared to that of (Example 1), while achieving the purpose of oil prevention, it can also avoid as much as possible the target noise loss caused by excessive turning angles, which affects the accuracy of sound collection.

[0106] This embodiment also relates to a range hood, comprising an air duct 10 for smoke to pass through and an active noise reduction system provided in the air duct 10, wherein the active noise reduction system comprises the above-mentioned sound collection device.

[0107] Example 3

[0108] Figures 11 - 14 Another preferred embodiment of the sound collection device and range hood of the present invention is shown. This embodiment differs from the first embodiment in that the sound collection channel 200 extends vertically as a whole and comprises two sections arranged sequentially from top to bottom: a vertically extending upper section 201 (also known as the vertical section) and a lower section 202 (also known as the inclined section) that slopes downward toward the location of the receiving slot 21 of the mounting frame 20. The upper section 201 of the sound collection channel 200 constitutes the main body of the sound collection channel 200. The opening of the first sound inlet 211 of the receiving slot 21 of the mounting frame 20 is arranged obliquely upward toward B1, and its inclination direction is consistent with the inclination direction of the lower section 202 of the sound collection channel 200. More specifically, the first angle M formed between the opening direction B1 of the first sound inlet 211 and the extension direction of the upper section 201 of the sound collection channel 200 is also an acute angle, with a value range of 5°≤M<90°. Preferably, the value range of the first angle M is 30°≤M≤80°. The portions of the front wall of the mounting frame 20 corresponding to the upper section 201 and the lower section 202 of the sound collection channel 200 are respectively a vertical surface 20a and an inclined surface 20b. In addition, byFigure 11 It can be seen that the position of the vertical surface 20a of the mounting bracket 20 and the position of the accommodating groove 21 (that is, the position of the sound collecting element 11) are offset in the upper and lower directions, that is, the sound collecting element 11 is closer to the side wall of the air duct 10 for placing the mounting bracket 20, while the vertical surface 20a of the mounting bracket 20 is relatively far away from the side wall of the air duct 10 for placing the mounting bracket 20.

[0109] In this embodiment, the vertical surface 20a of the mounting frame 20 intersects with the inclined surface 20b to form a second angle N. Due to the differences in viscosity, surface tension, and roughness of the wall material, the oil droplets are subject to gravity, adhesion, surface tension, and friction on the inclined surface. When the inclined surface 20b has different inclination angles (i.e., the second angle N), the combined effects of these different forces result in different movement of the oil droplets. Figure 11 As shown, when the second angle N is 80°≥N≥30°, since the components of the adhesion and friction forces resisting gravity in the vertical direction are relatively small, the oil will flow down from the vertical surface 20a and accumulate at the corner to a certain extent before falling directly. Moreover, due to the structural staggered design, the oil droplets will not drip onto the sound collecting element 11. Figure 13 As shown, when the second angle N is 30° > N ≥ 5°, due to the greater vertical component of adhesion and friction forces resisting gravity, oil will flow down vertical surface 20a, past the corner, and along inclined surface 20b, reaching sound collecting element 11. Therefore, the lower end of vertical surface 20a of mounting bracket 20, where it meets inclined surface 20b, is provided with a downwardly extending overhanging edge 20c. By adding an overhanging edge 20c at the corner where vertical surface 20a and inclined surface 20b meet, oil droplets gradually accumulate along overhanging edge 20c and drip vertically, preventing them from falling onto sound collecting element 11.

[0110] The propagation path of the sound in the protective device of this embodiment is a turning path, such as Figure 11 and Figure 13 This path S is shown in Figure 1. Because the sound propagation path of this embodiment has a gentler turning angle than that of Example 1, it achieves oil protection while minimizing the loss of target noise caused by excessive turning angles, which could affect the accuracy of sound collection. Furthermore, compared to Example 2, the sound collection channel 200 of this embodiment is positioned as close as possible to the sidewalls of the air duct 10, preventing the protective device from protruding too far from the sidewalls within the air duct 10 and potentially affecting the stability of the airflow within the air duct 10.

[0111] This embodiment also relates to a range hood, comprising an air duct 10 for smoke to pass through and an active noise reduction system provided in the air duct 10, wherein the active noise reduction system comprises the above-mentioned sound collection device.

[0112] Example 4

[0113] Figure 15 and Figure 16 shows another preferred embodiment of the sound collection device and the range hood of the present invention. The difference between this embodiment and Embodiment 1 is that: the sound collection channel 200 is a vertically extending straight channel, and the opening direction of the first sound inlet 211 of the accommodation groove 21 of the mounting bracket 20 is set obliquely downward, and the height of the position where the sound collection element 11 is located in the accommodation groove 21 is higher than the height of the opening position of the first sound inlet 211. The first included angle M formed between the opening direction of the first sound inlet 211 and the extending direction of the sound collection channel 200 is an obtuse angle, and its value range is: 90° < M < 180°. Preferably, the value range of the first included angle M is: 100° < M < 150°. It can be seen from Figure 15 that the propagation path of sound in the protection device in this embodiment is a turning path of "first downward and then obliquely upward", as Figure 15 shown by the path S therein. Since the turning angle of the sound propagation path in this embodiment is relatively large (compared with Embodiment 1), especially, the opening of the first sound inlet 211 is set obliquely downward, so a better oil-proof purpose can be achieved, but due to the too large turning angle, certain losses of the target noise are caused, which has a certain impact on the accuracy of sound collection.

[0114] This embodiment also relates to a range hood, which includes a flue Ⅰ0 for the passage of flue gas and an active noise reduction system provided in the flue Ⅰ0. The active noise reduction system includes the above-mentioned sound collection device.

[0115] Example 5

[0116] Figure 17 and Figure 18 shows another preferred embodiment of the sound collection device and the range hood of the present invention. The difference between this embodiment and Embodiment 1 is that: the main body 203 of the sound collection channel 200 is a vertically extending straight channel. Among them, the lower part of the sound collection channel 200 also has a horizontal section 204 extending horizontally. The lower end of the main body of the sound collection channel 200 is connected to one end of the horizontal section 204, and the opening direction of the first sound inlet 211 of the accommodation groove 21 of the mounting bracket 20 faces downward and is connected to the other end of the horizontal section 204 of the sound collection channel 200. The first included angle M formed between the orientation of the first sound inlet 211 and the extending direction of the main body of the sound collection channel 200 is a flat angle, that is, the value range of the first included angle M is 180°. It can be seen from Figure 17 that the propagation path of sound in the protection device in this embodiment is a turning path of "first downward, then horizontally, and finally upward", as Figure 17The turning path S is shown therein. Since the sound collection channels in this embodiment are divided into two sections, one vertically arranged and the other horizontally arranged, and the opening direction of the first sound inlet 211 faces downward, the sound propagation path in the protection device of this embodiment undergoes two "turns". Therefore, it can also achieve a good oil prevention purpose. However, due to the excessive turning angle and the large number of turns, certain losses of the target noise occur, which has a certain impact on the accuracy of sound collection.

[0117] This embodiment also relates to a range hood, which includes a flue 10 for the passage of flue gas and an active noise reduction system provided in the flue 10. The active noise reduction system includes the above-mentioned sound collection device.

Claims

1. A sound acquisition device, comprising a sound acquisition element (11), characterized in that: The invention also includes a shell (2), on which a sound propagation channel is defined. The sound propagation channel includes a first channel section and a second channel section that are connected in sequence and arranged at an angle. The sound collecting element (11) is located in the first channel section. The first channel section has a first sound inlet (211) that is connected to the second channel section. The second channel section has a second sound inlet (45) for external sound to enter. The second channel section is also provided with a windproof and sound-permeable member (30). The opening area at the first sound inlet (211) is recorded as S. The area of the cross section formed by cutting the windproof and sound-permeable member (30) in the extension direction of the second channel section is recorded as S3. The value range of S3 / S is: 13.5≥S3 / S≥1.

5.

2. The sound collection device according to claim 1, wherein: The value range of S3 / S is: 13.5≥S3 / S≥2.

5.

3. The sound collection device according to claim 2, wherein: The value range of S3 / S is: 7≥S3 / S≥2.

5.

4. The sound collection device according to any one of claims 1 to 3, characterized in that: The above-mentioned sound collection device is arranged in the air duct (10) of the range fumes extraction device, the second channel section is arranged along the extension direction of the air duct (10), and the second sound inlet (45) is formed at the leeward end of the shell (2), and the opening direction (B4) of the second sound inlet (45) is consistent with the extension direction of the air duct.

5. The sound collection device according to claim 4, characterized in that: The main body of the second channel section extends vertically, and the first angle formed by the intersection of the opening direction (B1) of the first sound inlet (211) and the extension direction of the second channel section is recorded as M, and the value range of the first angle is: 5°≤M≤180°.

6. The sound collection device according to claim 5, wherein: The extension direction of the sound collection channel (200) and the air duct (10) are both vertical, the opening of the second sound inlet (45) faces upward, and the opening direction (B1) of the first sound inlet (211) is perpendicular to the extension direction of the second channel section, that is, the first angle is a right angle.

7. The sound collection device according to claim 4, wherein: The shell (2) includes a mounting frame (20) and a windshield (40). A receiving groove (21) is provided on the front side wall of the mounting frame (20). The sound collecting element (11) is placed in the receiving groove (21). The receiving groove (21) constitutes the first channel section. The front opening of the receiving groove (21) is the first sound inlet (211). The windshield (40) is arranged outside the mounting frame (20) and defines a sound collecting channel (200) between the windshield (40) and the mounting frame (20). The sound collecting channel (200) is connected to the first sound inlet (211) of the receiving groove (21) and is located in front of the receiving groove (21). The second channel section is defined by the leeward end of the windshield (40) and the mounting frame (20).

8. The sound acquisition device according to claim 7, wherein: The front side wall of the windproof and sound-permeable component (30) is in contact with the rear side wall of the windproof cover (40).

9. The sound collection device according to claim 7, wherein: A grease-proof sound transmission membrane (28) that shields the front side of the sound collection element (11) is further provided at the first sound inlet (211). A fourth distance is provided between the grease-proof sound transmission membrane (28) and the sound collection element (11), and this fourth distance is denoted as f. Among them, the value range of f is: f ≥ 2 mm.

10. The sound acquisition device according to claim 9, wherein: The cross-sectional area of the second channel segment at a position adjacent to the second sound inlet (45) is denoted as S0, the volume of the inner cavity formed by the oil-proof sound-transmitting membrane (28) and the inner wall of the receiving groove (21) is denoted as V, the dimension of the main body of the wind-proof sound-transmitting member (30) in the front-rear direction is denoted as e, and the dimension of the wind-proof sound-transmitting member (30) in the up-down direction is denoted as g, where:

11. An oil fume suction machine, comprising an air duct (10) for flue gas to pass through and a sound collection device arranged in the air duct (10), characterized in that: The described sound collection device adopts the sound collection device described in any one of claims 1 to 10.

12. The range hood according to claim 11, wherein: The described sound collection element (11) is a microphone.

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