Hybrid broadband noise reduction device and range hood

Abstract

The invention relates to a hybrid broadband noise reduction device which comprises a shell and a cavity with a rear opening, and an opening is formed in the bottom of the shell. The micro-perforated plate is arranged on the opening of the shell in a covering manner; and the plasma noise reduction module is matched with the opening and is arranged in the shell, and a cavity is formed between the plasma noise reduction module and the micro-perforated plate. The hybrid broadband noise reduction device can reduce noise in a wider frequency range at the same time. The invention further relates to a range hood, the range hood comprises a machine shell, a fan arranged in the machine shell and the hybrid broadband noise reduction device, the hybrid broadband noise reduction device faces the fan and is arranged in the machine shell, and one side of the micro-perforated plate is arranged close to the fan.

Description

Technical Field

[0001] This invention relates to a hybrid broadband noise reduction device and a range hood. Background Technology

[0002] Currently, the mainstream noise reduction technologies are mainly divided into two types: passive noise reduction technology and active noise reduction technology.

[0003] Passive noise reduction technology uses sound-absorbing cotton, porous materials, fiber materials, and partitions to block noise transmission, thus achieving noise reduction. Passive noise reduction is very effective for high-frequency noise because high-frequency sound waves have shorter wavelengths and are easily absorbed or reflected by materials. Essentially, the heat loss of porous materials is roughly equivalent to the wavelength, effectively absorbing sound. However, for low-frequency noise such as engine roar or low-frequency vibrations, passive noise reduction is relatively less effective because low-frequency sound waves have longer wavelengths, usually requiring thicker materials or large-volume structures for effective attenuation. Limited control over low-frequency noise, increased size and weight, comfort issues, poor adaptability, high cost and complex installation, aesthetic limitations, and irreversibility are all problems inherent in passive noise reduction technology.

[0004] Active noise cancellation technology, including antisonic noise cancellation, is a method that cancels out noise by generating sound waves with the opposite phase to the noise. This technology is widely used in headphones, automobiles, aircraft, and industrial equipment to improve auditory comfort and reduce the impact of ambient noise. Antisonic noise cancellation is effective at handling low-frequency noise in small spaces because sound reflection and scattering are more frequent, making wave interference easier to achieve. However, it is less effective at handling mid-frequency noise and noise in three-dimensional space because the propagation direction of sound waves is chaotic in three-dimensional space, making precise alignment impossible. This results in some areas experiencing active noise cancellation while others experience active noise amplification.

[0005] Active noise cancellation technology also includes acoustic impedance matching noise cancellation technology, which maximizes the transfer of acoustic energy by adjusting the impedance between two different media, thereby enabling the acoustic system to work effectively.

[0006] When sound waves propagate between two different media, reflection and refraction occur when they encounter impedance mismatch. If the acoustic impedances of the two media differ significantly, it leads to substantial reflection and energy loss. By adjusting the density and velocity of sound in the media to achieve impedance matching, sound wave reflection can be minimized, allowing for better sound energy transmission. Impedance matching is a core principle behind porous materials; when noise enters a porous material, it rubs against the internal porous structure, consuming energy. Micro-perforated plates have a certain range of sound absorption frequency bands, but they cannot completely cover the noise frequency band.

[0007] It is evident that there is currently no noise reduction device that can simultaneously address low-frequency, mid-frequency, and high-frequency noise issues. This limits the application environment of various noise reduction devices and also affects their noise reduction effectiveness. Summary of the Invention

[0008] The first technical problem to be solved by the present invention is to provide a hybrid broadband noise reduction device that can simultaneously reduce noise over a wider frequency range, in contrast to the above-mentioned prior art.

[0009] The second technical problem to be solved by the present invention is to provide a range hood that applies the aforementioned hybrid broadband noise reduction device, in contrast to the prior art.

[0010] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a hybrid broadband noise reduction device, characterized in that: it includes...

[0011] The outer casing has a cavity that opens to the rear and has an opening at the bottom;

[0012] A micro-perforated plate is installed over the opening of the outer casing;

[0013] A plasma noise reduction module is matched with an opening set inside the housing, and there is a cavity between the plasma noise reduction module and the micro-perforated plate.

[0014] As an improvement, a sound-absorbing layer is also provided inside the housing. The rear side of the sound-absorbing layer is attached to the inner wall of the micro-perforated plate. A groove is provided on the front side of the sound-absorbing layer to match the outer contour of the plasma noise reduction module. The plasma noise reduction module is embedded in the groove, and there is a gap between the plasma noise reduction module and the bottom of the groove.

[0015] Preferably, the outer casing is generally funnel-shaped, and the outer casing is inclined from the edge of the opening towards the rear.

[0016] As an improvement, the plasma noise reduction module includes

[0017] The casing is designed to open rearward;

[0018] A metal mesh panel is installed over the opening of the housing, and the metal mesh panel is grounded.

[0019] The electrode wires consist of multiple wires arranged in parallel within the housing. The electrode wires are spaced apart from the metal mesh plate and the bottom of the housing. The electrode wires are connected to a power source.

[0020] Preferably, each electrode wire is sequentially and integrally connected and disposed within the housing.

[0021] For ease of setup, multiple protrusions are spaced apart on the opposite side walls of the housing, and the electrode wire is wound continuously in an S-shape around the protrusions.

[0022] To improve the stability of the metal mesh panel installation, the metal mesh panel is supported on the protruding pillars.

[0023] As an improvement, the thickness, perforation rate, perforation diameter, and cavity depth of the micro-perforated plate are adjusted so that the resonant frequency of the micro-perforated plate meets the mid-frequency noise range of the micro-perforated plate to be noise-reduced, and the relative acoustic impedance and sound absorption coefficient of the micro-perforated plate are close to 1.

[0024] As an improvement, the power supply parameters to the plasma noise reduction module were adjusted so that the plasma noise reduction module could meet the noise reduction requirements in the low-frequency noise range.

[0025] The technical solution adopted by the present invention to solve the second technical problem mentioned above is as follows: a range hood, including a housing, a fan installed inside the housing, and the aforementioned hybrid broadband noise reduction device, wherein the hybrid broadband noise reduction device is installed inside the housing facing the fan, and one side of the micro-perforated plate is installed close to the fan.

[0026] Compared with existing technologies, the advantages of this invention are as follows: The hybrid broadband noise reduction device of this invention incorporates a micro-perforated plate and a plasma noise reduction module, enabling simultaneous passive and active noise reduction. These noise reduction structures provide better noise reduction for different frequency bands and enhance the noise reduction effect within overlapping frequency ranges, thereby achieving a wider noise reduction frequency range. Furthermore, this hybrid broadband noise reduction device does not require expanding volume or area to achieve a wider noise reduction frequency range, facilitating a compact design, reducing its space footprint in products, and promoting miniaturization.

[0027] The range hood that uses this hybrid broadband noise reduction device has a better noise reduction effect, improving the user experience. Attached Figure Description

[0028] Figure 1 This is a perspective view of the hybrid broadband noise reduction device in an embodiment of the present invention.

[0029] Figure 2 This is an exploded view of the hybrid broadband noise reduction device in an embodiment of the present invention.

[0030] Figure 3 This is a cross-sectional view of the hybrid broadband noise reduction device in an embodiment of the present invention.

[0031] Figure 4 This is a cross-sectional view of the application of the hybrid broadband noise reduction device in a range hood according to an embodiment of the present invention. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] like Figures 1 to 3 As shown, the hybrid broadband noise reduction device in this embodiment includes a housing 1, a micro-perforated plate 2, a plasma noise reduction module 3, and a sound-absorbing layer 4.

[0034] The design of the outer casing 1 facilitates the modular design of the hybrid broadband noise reduction device, thereby making it easier to install the hybrid broadband noise reduction device as a whole.

[0035] The outer shell 1 has a cavity that opens to the rear, and an opening 11 is provided at the bottom of the outer shell 1. A micro-perforated plate 2 is covered and disposed on the opening of the outer shell 1, thereby forming a box structure with the outer shell 1. In this embodiment, the micro-perforated plate 2 is made of woven fabric or textile, which facilitates the adjustment of parameters such as perforation diameter and porosity during the design stage. In this embodiment, the perforation diameter on the micro-perforated plate 2 is approximately 0.1 mm.

[0036] The plasma noise reduction module 3 is disposed within the housing 1, matching the opening 11, and a cavity exists between the plasma noise reduction module 3 and the micro-perforated plate 2. A sound-absorbing layer 4 is disposed within the housing 1, with its rear side attached to the inner wall of the micro-perforated plate 2. A groove is provided on the front side of the sound-absorbing layer 4 to match the outer contour of the plasma noise reduction module 3, and the plasma noise reduction module 3 is embedded within the groove, with a gap between the plasma noise reduction module 3 and the bottom of the groove. In other words, the sound-absorbing layer 4 is disposed within the cavity based on the cavity shape of the micro-perforated plate 2 and the plasma noise reduction module 3, and the sound-absorbing layer 4 can be configured into an irregular shape to match the cavity shape.

[0037] The sound-absorbing layer 4 is mainly made of flexible sound-absorbing materials, such as sound-absorbing cotton. The sound-absorbing layer 4 is mainly used to reduce high-frequency noise. For a specific product, the high-frequency noise range that the sound-absorbing layer 4 needs to reduce can be determined through preliminary experimental testing. Then, the material, thickness, and density of the sound-absorbing layer 4 can be adjusted to achieve the desired high-frequency noise reduction.

[0038] To maximize the coverage of noise propagation area within the limited space of the product, the outer casing 1 in this embodiment is generally horn-shaped, and the outer casing 1 is gradually inclined backward from the edge of the opening 11. This increases the area of ​​the micro-perforated plate 2, thereby covering the noise source's emission range as much as possible.

[0039] The plasma noise reduction module 3 in this embodiment includes a housing 31, a metal mesh plate 32, and an electrode wire 33.

[0040] The housing 31 is open at the rear, and its external contour can be customized as needed, such as being circular, rectangular, or irregular in shape. A metal mesh plate 32 covers the opening of the housing 31, thus forming a flat box structure with the insulating shell. The metal mesh plate 32 can be made of stainless steel and is grounded. To facilitate grounding, a grounding hole is provided on the edge of the insulating shell, through which the ground wire passes and is electrically connected to the metal mesh plate 32. The plasma generator and the metal mesh plate 32 work together to form a plasma flow for noise reduction.

[0041] Multiple electrode wires 33 are arranged parallel to each other within the housing 31. There are gaps between the electrode wires 33 and the metal mesh plate 32, as well as the bottom of the housing 31. The electrode wires 33 are connected to a power source. In this embodiment, the electrode wires 33 are made of nickel-chromium wire. During operation, a voltage exceeding its corona initiation voltage is applied to the electrode wires 33, thereby generating plasma. Simultaneously, an AC power source is coupled. The ions generated on the electrode wires 33 converge and are absorbed by the metal mesh plate 32 under the influence of the electric field. Based on the movement of the plasma, air is pushed to form a pressure wave, which cancels out noise through a reverse sound wave.

[0042] The combined operation of electrode wire 33 and metal mesh plate 32 provides excellent noise reduction for low-frequency noise. It also offers some noise reduction for mid-to-high-frequency noise.

[0043] To facilitate the installation of the electrode wires 33 on the housing 31 and improve installation efficiency, each electrode wire 33 is sequentially and integrally connected and wound around the housing 31. That is, a single electrode wire is arranged in a continuous S-shape to form multiple parallel electrode wires 33. In this embodiment, a winding method is specifically used to install the electrode wires 33 on the housing 31. To facilitate winding the electrode wires 33, multiple protrusions 311 are spaced apart on opposite side walls of the housing 31, and the electrode wires 33 are wound in a continuous S-shape around the protrusions 311. The width of the protrusions 311 and the spacing between them are the same, thus ensuring that the spacing between each electrode wire 33 is the same. The two ends of the electrode wire are fixed to the frame of the housing 31.

[0044] Based on the protruding column 311, the metal mesh plate 32 can also be supported on the protruding column 311. The protruding column 311 forms an effective support for the side of the metal mesh plate 32, ensuring the stability of the structure. At the same time, in order to further improve the support stability of the metal mesh plate 32, a support step is also provided on the side of the shell 31. The two sides of the metal mesh plate 32 that are not supported by the protruding column 311 are supported on the support step.

[0045] In this embodiment, the micro-perforated plate 2 mainly reduces mid-frequency noise in the range of 1500-3000Hz using passive noise reduction, the plasma noise reduction module 3 mainly reduces low-frequency noise in the range of 20-2000Hz using active noise reduction, and the sound-absorbing layer 4 mainly reduces high-frequency noise in the range of 2000-20000Hz using passive noise reduction. Of course, there is some overlap in the noise reduction frequency ranges of the micro-perforated plate 2, the plasma noise reduction module 3, and the sound-absorbing layer 4.

[0046] Different types of noise have different noise distribution ranges and core noise frequency bands. Accordingly, when designing a hybrid broadband noise reduction device, some structural parameters in the micro-perforated plate 2, plasma noise reduction module 3, and sound-absorbing layer 4 are adjusted to achieve a good noise reduction effect over a wide frequency range. As mentioned earlier, the noise reduction frequency band range of the sound-absorbing layer 4 is adjusted by modifying its material, thickness, and density.

[0047] For the micro-perforated plate 2, adjusting its thickness, perforation rate, perforation diameter, and cavity depth allows the resonant frequency of the micro-perforated plate 2 to meet the mid-frequency noise range for which it needs noise reduction, thus making its relative acoustic impedance and sound absorption coefficient close to 1. For example, by adjusting these parameters, the resonant frequency of the micro-perforated plate 2 can be adjusted. When its resonant frequency is adjusted to 2250Hz, the peak frequency of noise absorption by the micro-perforated plate 2 corresponds to around 2000-2500Hz, and its corresponding sound absorption frequency range is 1500-3000Hz, with a sound absorption coefficient reaching a level close to 1 (e.g., 0.9). Meanwhile, by adjusting the thickness, perforation rate, perforation diameter, and cavity depth of the micro-perforated plate 2, the acoustic impedance of the micro-perforated plate 2 can be made close to the relative acoustic impedance of the noise characteristic impedance, thereby achieving impedance matching with the noise and maximizing the absorption and dissipation of noise energy in this frequency band.

[0048] For the plasma noise reduction module 3, the power supply parameters of the plasma noise reduction module 3 are adjusted so that it can meet the noise reduction requirements within the low-frequency noise range. In this embodiment, the power supply parameters of the plasma noise reduction module 3 are adjusted so that its target impedance equals the air impedance. When the air impedance equals the target impedance of the plasma generator 2, noise absorption is achieved. During the product design phase, to achieve better noise reduction, the noise parameters at the front and rear of the plasma noise reduction module 3 are detected, and the power supply parameters of the plasma noise reduction module 3 are adjusted based on these noise parameters to match the unreduced noise frequency band.

[0049] The hybrid broadband noise reduction device of this invention incorporates a micro-perforated plate 2 and a plasma noise reduction module 3. These noise reduction structures enable better noise reduction across different frequency bands and enhance the noise reduction effect within overlapping frequency ranges, thereby achieving a wider noise reduction frequency range. Furthermore, this hybrid broadband noise reduction device does not require increasing volume or area to achieve a wider noise reduction frequency range, facilitating a compact design, reducing its space footprint in products, and promoting miniaturization.

[0050] like Figure 4 As shown, the present invention also relates to a range hood, including a housing 5, a fan 6 disposed within the housing 5, and the aforementioned hybrid broadband noise reduction device. The hybrid broadband noise reduction device is disposed within the housing 5 facing the fan 6, and one side of the micro-perforated plate 2 is disposed close to the fan 6. When the range hood is working, the noise generation area is concentrated at the volute of the fan 6, and the fan 6 frame is usually disposed outside the volute. In this embodiment, based on the trumpet-shaped arrangement of the outer shell 1, the micro-perforated plate 2 can cover the entire fan 6 frame area.

[0051] Range hoods that utilize this hybrid broadband noise reduction device offer better noise reduction and enhance the user experience.

[0052] The specification and claims of this invention use terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "side," "top," and "bottom," to describe various exemplary structural parts and elements of the invention. However, these terms are used herein merely for ease of explanation and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this invention can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

Claims

1. A hybrid broadband noise reduction device, characterized in that: include The outer shell (1) has a cavity that opens to the rear and has an opening (11) at the bottom; A micro-perforated plate (2) is provided to cover the opening of the outer casing (1); The plasma noise reduction module (3) is matched with the opening (11) and is set inside the shell (1). There is a cavity between the plasma noise reduction module (3) and the micro-perforated plate (2).

2. The hybrid broadband noise reduction device according to claim 1, characterized in that: It also includes a sound-absorbing layer (4) disposed inside the outer shell (1). The rear side of the sound-absorbing layer (4) is attached to the inner wall of the micro-perforated plate (2). The front side of the sound-absorbing layer (4) is provided with a groove matching the outer contour of the plasma noise reduction module (3). The plasma noise reduction module (3) is embedded in the groove, and there is a gap between the plasma noise reduction module (3) and the bottom of the groove.

3. The hybrid broadband noise reduction device according to claim 1, characterized in that: The outer shell (1) is generally horn-shaped, and the outer shell (1) is inclined to gradually spread outward from the edge of the opening (11).

4. The hybrid broadband noise reduction device according to any one of claims 1 to 3, characterized in that: The plasma noise reduction module (3) includes The housing (31) is open to the rear; A metal mesh plate (32) is provided to cover the opening of the housing (31), and the metal mesh plate (32) is grounded; The electrode wire (33) includes multiple wires arranged in parallel inside the housing (31). There is a gap between the electrode wire (33) and the metal mesh plate (32) and the bottom of the housing (31). The electrode wire (33) is connected to the power supply.

5. The hybrid broadband noise reduction device according to claim 4, characterized in that: Each electrode wire (33) is connected in sequence and disposed in the housing (31).

6. The hybrid noise reduction device according to claim 5, characterized in that: Multiple protrusions (311) are provided at intervals on the opposite side walls of the housing (31), and the electrode wire (33) is wound in a continuous S-shape on the protrusions (311).

7. The hybrid noise reduction device according to claim 6, characterized in that: The metal mesh plate (32) is supported on the protruding column (311).

8. The hybrid broadband noise reduction device according to any one of claims 1 to 3, characterized in that: Adjust the thickness, perforation rate, perforation diameter, and cavity depth of the micro-perforated plate (2) so that the resonant frequency of the micro-perforated plate (2) meets the mid-frequency noise frequency range of the micro-perforated plate (2) to be noise-reduced, and make the relative acoustic impedance and sound absorption coefficient of the micro-perforated plate (2) close to 1.

9. The hybrid broadband noise reduction device according to any one of claims 1 to 3, characterized in that: Adjust the power supply parameters of the plasma noise reduction module (3) so that the plasma noise reduction module (3) can meet the noise reduction work in the low frequency noise range.

10. A range hood, comprising a housing (5) and a fan (6) disposed within the housing (5), characterized in that: It also includes the hybrid broadband noise reduction device according to any one of claims 1 to 9, wherein the hybrid broadband noise reduction device is disposed in the housing (5) facing the fan (6), and one side of the micro-perforated plate (2) is disposed close to the fan (6).

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