A noise reduction type fan volute and a range hood

Abstract

This invention discloses a noise-reducing fan casing and a range hood. The noise-reducing fan casing includes a casing body, a volute tongue, and a noise-reducing part. The volute tongue includes a volute tongue body; a guide part recessed in the inner wall of the volute tongue body for guiding airflow; and multiple micropores penetrating the guide part and the volute tongue body for transmitting noise. The noise-reducing part is installed in a cavity formed on the back of the volute tongue body to absorb noise transmitted from the micropores. This invention, by setting the guide part on the volute tongue body, can guide and direct the airflow at the volute tongue within the casing body, reducing the noise generated by the vortex formed by the airflow at the volute tongue, thus achieving noise reduction. The noise is then transmitted to the noise-reducing part through the micropores for absorption, further reducing noise. The combination of the guide part, micropores, and noise-reducing part improves the noise reduction effect.

Description

Technical Field

[0001] This invention belongs to the field of household appliances, specifically relating to a noise-reducing fan casing and a range hood. Background Technology

[0002] Kitchens in homes and restaurants inevitably produce large amounts of cooking fumes. To maintain kitchen cleanliness and protect human health, fume extraction systems have become essential equipment in these places. To meet people's needs, various fume extraction systems have long been available on the market. Typically, a fume extraction system includes a range hood and ductwork that vents the fumes outdoors or to a fume exhaust treatment system. Among range hoods, those with centrifugal fans are the most common, favored for their relatively strong suction and low noise. However, even so, the noise from the centrifugal fan itself, as well as the noise generated by turbulence in the fan casing and ductwork, adds up to a certain level of noise from the entire fume extraction system. To improve the fume removal effect, manufacturers often increase the airflow and / or air pressure, and even the power of the centrifugal fan, which further increases the noise of the entire fume extraction system. Excessive noise can cause headaches, irritability, palpitations, and other adverse effects on the health of housewives and kitchen staff who work in such environments for extended periods.

[0003] Chinese patent application number CN201620153561.X discloses a fan volute for a range hood, including a volute tongue. The volute tongue includes an inner wall and forms a closed cavity. At least one longitudinal partition is arranged in the cavity along the axis of the volute, and multiple radial partitions are arranged in the cavity perpendicular to the axis of the volute. The longitudinal and radial partitions divide the cavity into multiple independent closed silencing cavities. Each silencing cavity has a hole on the inner wall of the volute tongue.

[0004] In the above scheme, the cavity within the volute tongue is divided into multiple independent, closed small cavities. These small cavities and the corresponding holes on their sidewalls form a Helmholtz resonator. When sound propagates, sound waves with frequencies close to the resonator's natural frequency resonate with it. During vibration, the air column within the cavity rubs against the cavity's inner wall, consuming sound energy and achieving noise reduction. However, this resonator can only resonate with noise having the same natural frequency, thus achieving the goal of eliminating noise with that natural frequency, and its noise reduction effect is limited.

[0005] In view of the above-mentioned technical deficiencies, this invention is proposed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a volute tongue with a guiding function. By guiding the flow of the volute tongue, the generation of vortices at the volute tongue is reduced, the vibration effect of the airflow inside the volute is reduced, and thus the noise reduction effect of the fan volute is improved.

[0007] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0008] A noise-reducing fan casing includes a casing body, a volute tongue, and a sound-absorbing part, wherein the volute tongue includes...

[0009] Cochlear tongue body;

[0010] A flow guide is recessed on the inner wall of the volute tongue body to guide airflow;

[0011] Multiple micropores are provided, penetrating the guide section and the volute tongue body, for transmitting noise;

[0012] The noise-absorbing part is installed in a cavity formed on the back of the volute tongue body to absorb noise transmitted from the micropores.

[0013] By adopting the above scheme, the guide section can guide the airflow direction, playing a role in diversion and flow diversion, reducing the noise generated by the vortex formed by the airflow at the volute tongue, thereby achieving noise reduction. Furthermore, the noise is transmitted to the silencing section through micro-holes for absorption, further reducing noise. The combination of the guide section, micro-holes, and silencing section improves the noise reduction effect. In addition, the reduction of vortices at the volute tongue increases the airflow, thereby increasing the air volume of the fan casing.

[0014] Furthermore, the air guide extends from the side near the volute body along the air outlet direction to the side near the air outlet of the volute body on the volute tongue body.

[0015] By adopting the above solution, the direction of the air guide can be aligned with the direction of the air outlet, which can help to organize and guide the airflow from the outlet, shorten the airflow path, reduce vibration, and thus reduce noise.

[0016] Furthermore, the flow guiding part includes a flow guiding groove disposed on the inner wall of the volute tongue body; the flow guiding groove has a groove structure;

[0017] Preferably, the guide groove is perpendicular to the axial direction of the volute body;

[0018] Preferably, the flow guide groove is provided in multiple ways;

[0019] Preferably, the depth of the guide channel is 2-5mm, and the width of the channel is 2-4 times the depth of the channel.

[0020] By adopting the above scheme, the groove structure facilitates the guidance of airflow at the volute tongue, changes the direction of airflow, and multiple guide grooves can improve the diversion effect. In addition, the groove structure can also reflect noise, increase the noise path, and thus absorb noise, thereby achieving the purpose of reducing noise.

[0021] Furthermore, the flow guide is a corrugated pressed structure with the volute tongue body undulating along the axial direction of the volute shell, and the flow guide groove is the trough of the corrugated flow guide.

[0022] By adopting the above solution, the guide section and the volute tongue body are integrated into a single structure. This improvement on the existing volute tongue body structure achieves both airflow guidance and noise absorption reflection, while fully utilizing the volute tongue body's structure, simplifying its design, reducing production difficulty and costs, and saving manpower and resources. Furthermore, the guide groove structure on the volute tongue body increases the volume of the volute's chambers, further increasing airflow during fan rotation.

[0023] Furthermore, the micropores are disposed at the bottom of the guide channel and are spaced apart along the extension direction of the guide channel;

[0024] Preferably, the diameter of the micropores is 0.8-1 times the width of the bottom of the guide channel;

[0025] Preferably, the porosity of the micropores on the flow guide is not less than 50%.

[0026] By adopting the above solution, it is easy to create micro-holes during production. In addition, the micro-holes are located at the bottom of the tank, so that the airflow is guided and the noise is reflected multiple times before finally entering the silencing part from the bottom of the tank where the noise intensity is lowest. The silencing part then absorbs the noise, which can treat the noise to the greatest extent and prevent the noise from leaking out and affecting the user.

[0027] Furthermore, the structure of the sound-absorbing part matches the shape of the concave cavity formed on the back of the volute tongue body, and the sound-absorbing part fills the concave cavity;

[0028] Preferably, the silencing portion fills the cavity;

[0029] Preferably, the sound-absorbing part is a columnar sound-absorbing cotton.

[0030] By adopting the above solution, the sound-absorbing part makes full contact with the micropores, ensuring that noise entering through the micropores can be transmitted to the sound-absorbing part to the greatest extent and then absorbed. In addition, the sound-absorbing cotton has a porous structure, which allows noise to be reflected multiple times within the pore structure, gradually weakening the sound energy and thus achieving the purpose of sound absorption and ensuring the sound absorption effect.

[0031] Furthermore, the side of the volute tongue facing the cavity inside the volute shell and / or the exterior of the sound-absorbing part are coated with an oil-resistant coating.

[0032] By adopting the above solution, the oil-proof coating has the property of not sticking to oil. When oil stains reach the oil-proof coating, they will only flow away and will not stick and thicken. This prevents the micropores, guide grooves and guide parts from being blocked by oil stains. In particular, the sound-absorbing part has a porous structure, which makes it easier to absorb oil stains. The oil-proof coating can ensure that the volute tongue body and the sound-absorbing part can achieve the purpose of effective sound absorption and noise reduction for a long time.

[0033] Furthermore, the volute tongue and the volute body are detachably connected;

[0034] Preferably, the volute tongue and the volute body are connected by screws.

[0035] By adopting the above solution, when the guide part and / or micropores of the volute tongue are blocked by oil, the volute tongue can be removed, making it convenient for users to clean or replace it, thus replacing the fan volute with a new one instead of the user. This not only ensures the sound absorption and noise reduction effect of the volute tongue, but also reduces the user's living costs.

[0036] Furthermore, the volute tongue and the muffler are detachably connected.

[0037] By adopting the above solution, when the muffler is clogged with oil, the muffler can be removed separately, making it convenient for users to clean or replace it. This ensures the sound absorption effect of the volute tongue body while reducing the user's living costs.

[0038] Another object of the present invention is to provide a range hood having the aforementioned noise-reducing fan casing.

[0039] By adopting the above solutions, the noise generated by the range hood fan can be effectively reduced, thereby minimizing the harm of noise to the user's health during use, protecting the user's physical and mental well-being, and bringing a better living experience.

[0040] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0041] 1. The guide section of the volute tongue guides and organizes the airflow, reducing noise generated by vortices formed at the volute tongue, thus achieving noise reduction. The noise is then transmitted to the silencing section through micropores for absorption, further reducing noise. The guide section, micropores, and silencing section work together to improve noise reduction. Furthermore, the reduced vortices at the volute tongue increase airflow, thereby increasing the air volume of the fan casing.

[0042] 2. The airflow guide section features a continuously undulating corrugated structure along the axial direction of the volute. The airflow guide grooves are recessed areas on the surface of the volute tongue body. This design facilitates airflow guidance at the volute tongue, altering its direction and improving the airflow diversion effect. It also reflects noise, increasing its path and thus absorbing it for noise reduction. Furthermore, improvements have been made to the existing volute tongue body structure, integrating the airflow guide section with the volute tongue body. This fully utilizes the volute tongue body's structure, simplifies its design, reduces production difficulty, and lowers production costs. Moreover, the airflow guide groove structure on the volute tongue body increases the volume of the volute's chambers, further increasing airflow during fan rotation.

[0043] 3. The micro-holes are located at the bottom of the guide channel, which facilitates the creation of micro-holes during manufacturing. In addition, the micro-holes are located at the bottom of the channel, so that after the airflow is guided and the noise is reflected multiple times, it finally enters the silencer from the bottom of the channel where the noise intensity is lowest. The silencer then absorbs the noise, which can treat the noise to the greatest extent and prevent the noise from leaking out and affecting the user.

[0044] 4. The sound-absorbing part is a sound-absorbing cotton that completely fills the concave cavity, allowing the sound-absorbing part to make full contact with the micropores. This ensures that noise entering through the micropores can be transmitted to the sound-absorbing part to the greatest extent and then absorbed, thus ensuring the sound-absorbing effect.

[0045] 5. The side of the volute tongue facing the volute body and the outside of the muffler are coated with an oil-proof coating to prevent the micropores, the flow guide, and the muffler from being blocked by oil, ensuring that the volute tongue and the muffler can effectively absorb sound and reduce noise for a long time.

[0046] 6. The volute tongue and the volute body are detachably connected, and the volute tongue and the muffler are detachably connected. When the volute tongue or the muffler malfunctions, or when the guide part, micropores, or muffler are blocked by oil, the volute tongue or the muffler can be removed and replaced or cleaned separately. This is simple and convenient, ensuring the sound absorption effect of the volute tongue while reducing the user's living costs.

[0047] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0048] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0049] Figure 1 This is a schematic diagram of the structure of the noise-reducing fan casing of the present invention;

[0050] Figure 2 This is a schematic diagram of the structure of the cochlear tongue of the present invention;

[0051] Figure 3 yes Figure 2 Another perspective illustration;

[0052] Figure 4 This is a schematic diagram of the surface structure of the snail tongue of the present invention;

[0053] Figure 5 This is a schematic diagram of the structure of the noise reduction part of the present invention.

[0054] In the diagram: 1. Volute body; 2. Volute tongue; 201. Volute tongue body; 202. Micropores; 203. Guide groove; 204. Cavity; 3. Silencing part; 4. Air outlet.

[0055] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0057] In the description of this invention, it should be noted that the terms "upper," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0058] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0059] like Figures 1 to 5As shown, a noise-reducing fan casing includes a casing body 1, a volute tongue 2, and a noise-absorbing part 3. The volute tongue 2 includes a volute tongue body 201; a flow guide portion recessed on the inner wall of the volute tongue body 201 for guiding airflow; and multiple micropores 202 penetrating the flow guide portion and the volute tongue body 201 for transmitting noise. The noise-absorbing part 3 is installed in a cavity 204 formed on the back of the volute tongue body 201 for absorbing noise transmitted from the micropores 202.

[0060] The micropore 202 is located at the contact point between the volute tongue body 201 and the guide part or at the point where the two are closest, so that noise can be transmitted to the noise reduction part 3 through the micropore 202.

[0061] The guide section on the volute tongue 2 of this invention can guide and organize the airflow, reducing the noise generated by the vortex formed by the airflow at the volute tongue 2, thereby achieving noise reduction. The noise is then transmitted to the silencer section 3 through the micro-holes 202 for absorption, further reducing noise. The guide section, in conjunction with the micro-holes 202 and the silencer section 3, enhances the noise reduction effect. Furthermore, the reduction of vortices at the volute tongue increases the airflow, thereby increasing the air volume of the fan casing.

[0062] like Figure 1 As shown, the volute body 1 is provided with an air outlet 4.

[0063] The air guide extends from the side near the volute body 1 along the air outlet direction to the side near the air outlet 4 on the volute tongue body 201. This design ensures that the direction of the air guide is consistent with the direction of the air outlet, thus organizing and guiding the airflow out of the air outlet, shortening the airflow path, reducing vibration, and consequently reducing noise.

[0064] like Figures 2 to 4 As shown, the flow guiding part includes a flow guiding groove 203 disposed on the inner wall of the volute tongue body 201; the flow guiding groove 203 is a groove structure; preferably, the flow guiding groove 203 is perpendicular to the axial direction of the volute body 1; preferably, multiple flow guiding grooves 203 are provided; preferably, the groove depth of the flow guiding groove 203 is 2-5mm, and the groove width is 2-4 times the groove depth.

[0065] like Figure 2 and Figure 3 As shown, the opening of the guide groove 203 faces the cavity of the volute body 1, and the bottom of the groove is connected to the inner wall of the volute tongue body 201. Multiple guide grooves 203 are arranged in parallel and spaced apart or adjacent to each other. The width and depth of the guide groove 203 can be set according to actual needs.

[0066] The guide channel 203 can be square, rectangular, rounded rectangle, trapezoidal, wedge-shaped, or in other configurations.

[0067] The guide groove 203 is designed as a groove structure to facilitate the guidance of airflow at the volute tongue 2 and change the direction of airflow. Multiple guide grooves 203 can improve the flow guidance effect. In addition, the groove structure can also reflect noise, increase the noise path, and thus absorb noise and achieve the purpose of noise reduction.

[0068] like Figure 2 and Figure 3 As shown, the flow guide is a corrugated pressed structure of the volute tongue body 201 undulating along the axial direction of the volute shell, and the flow guide groove 203 is the trough of the corrugated flow guide.

[0069] like Figure 2 and Figure 3 As shown, the volute tongue body 201 is made by bending a corrugated plate, that is, the flow guide is formed by the volute tongue body 201, and the recess on the inner wall of the volute tongue body 201 is a flow guide groove 203 for guiding the airflow.

[0070] The micropores 202 are formed in the flow guide groove 203 and / or on the corrugated protrusions on the inner wall of the volute tongue body 201. Preferably, the micropores 202 are formed in the flow guide groove 203.

[0071] The flow guide section and the volute tongue body 201 are integrated into one structure. Improvements have been made to the existing structure of the volute tongue body 201, achieving both the purpose of flow guidance and full utilization of its structure. This simplifies the structure of the volute tongue 2, reduces production difficulty and costs, and saves manpower and resources. Furthermore, the flow guide groove 203 structure on the volute tongue body 201 increases the volume of the chamber in the volute body 1, further increasing airflow during fan rotation.

[0072] like Figure 2 and Figure 3 As shown, the micropores 202 are disposed at the bottom of the guide channel 203 and are spaced apart along the extension direction of the guide channel 203; preferably, the diameter of the micropores 202 is 0.8-1 times the width of the bottom of the guide channel 203; preferably, the opening ratio of the micropores 202 on the guide section is not less than 50%.

[0073] The aforementioned guide groove 203 has a depth of 2-5mm and a width 2-4 times its depth. The micro-holes 202 have a diameter 0.8-1 times the width of the guide groove 203. The micro-holes 202 on the guide section have an opening rate of not less than 50%, which fully utilizes the airflow guidance and noise transmission effects of the volute tongue 2, ensuring the noise reduction effect of the fan casing. Experimental data shows that, compared with the airflow without the guide groove 203, the airflow in this design is increased by 2.2%, and the noise level is reduced by 1.1%.

[0074] Multiple micropores 202 are provided so that the opening rate of the micropores 202 on the flow guide is not less than 50%, which facilitates the transmission of noise, increases the noise throughput, and thus increases the noise absorption of the noise reduction part 3, thereby improving the noise reduction effect.

[0075] The shape of the micropore 202 can be set to one or more of the following forms: round hole, elliptical hole, square hole, elongated hole, triangular hole, diamond hole, etc.

[0076] The micro-holes 202 of the present invention are disposed at the bottom of the guide channel 203. During the manufacturing process, it is convenient to open the micro-holes 202. In addition, the micro-holes 202 are located at the bottom of the channel, so that after the airflow is guided and the noise is reflected multiple times, it finally enters the noise reduction part 3 from the bottom of the channel where the noise intensity is the lowest. Then, the noise is absorbed by the noise reduction part 3, which can treat the noise to the greatest extent and prevent the noise from leaking out and affecting the user.

[0077] Furthermore, such as Figure 3 and Figure 5 As shown, the structure of the noise-absorbing part 3 matches the shape of the cavity 204 formed on the back of the worm tongue body 201, and the noise-absorbing part 3 fills the cavity 204; preferably, the noise-absorbing part 3 completely fills the cavity 204.

[0078] The sound-absorbing part 3 can be made of one or more of the following: porous sound-absorbing material, organic fiber material, inorganic fiber material, polystyrene material, inorganic foam material, and foam plastic material.

[0079] As a preferred option, such as Figure 5 As shown, the sound-absorbing part 3 is a columnar sound-absorbing cotton that perfectly matches the shape and size of the recess 204, completely filling the recess 204, or the sound-absorbing part 3 can overfill the recess 204, completely filling it. The sound-absorbing cotton, also known as acoustic cotton, is a roll / sheet material made from one or more different fibers processed through various techniques. It is formed from 100% polyester fiber through high-temperature hot pressing, achieving a sound absorption coefficient of 0.94 within a noise range of 125-4000Hz. Its excellent physical stability ensures that the sound-absorbing cotton will not expand or shrink due to temperature changes. Furthermore, polyester fiber is a fire-retardant material with excellent flame-retardant properties.

[0080] The sound-absorbing part 3 of this invention fills the cavity 204, allowing for sufficient contact between the sound-absorbing part 3 and the micropores 202. This ensures that noise entering through the micropores 202 is absorbed by the sound-absorbing part 3 to the greatest extent possible. Furthermore, the sound-absorbing cotton is a laminated, stepped-density porous material with interconnected pores. When sound enters the sound-absorbing cotton, it rubs against the pore walls, resulting in energy conversion and ultimately attenuating the sound energy, thus ensuring a sound-absorbing effect.

[0081] Furthermore, the side of the volute tongue 2 facing the cavity inside the volute shell and / or the exterior of the sound-absorbing part 3 are coated with an oil-resistant coating.

[0082] As a preferred embodiment, the side of the volute tongue 2 facing the cavity inside the volute shell and the exterior of the sound-absorbing part 3 are both coated with an oil-resistant coating.

[0083] If the volute tongue body 201 and the guide part are an integral structure, the oil-proof coating is applied to the inner wall of the volute tongue body 201. If the guide part is an independent structure set on the volute tongue body 201, the oil-proof coating is applied to the outer side of the guide part and the inner wall of the volute tongue body 201.

[0084] Since the fan casing of this invention can be applied to various devices, including range hoods, it is prone to accumulating oil stains. When oil stains accumulate on the volute tongue 2, they easily clog the flow guide and micropores 202, especially adhering to the outside of the muffler 3, causing the volute tongue 2 and the muffler 3 to lose their flow guide and noise reduction functions. The oil-resistant coating has non-stick properties; oil stains will only flow away after reaching the oil-resistant coating and will not stick and thicken, preventing the micropores 202, flow guide 203, and muffler 3 from being blocked by oil stains, and ensuring that the volute tongue 2 and the muffler 3 can effectively absorb sound and reduce noise for a long time.

[0085] The volute tongue 2 is made of a flame-retardant polymer material.

[0086] The volute tongue 2 and the volute body 1 are detachably connected. The volute tongue 2 and the volute body 1 can be connected by means of insertion, snap-fit, threaded connection, etc. Preferably, the volute tongue 2 and the volute body 1 are connected by screws.

[0087] When the guide part and / or micropores 202 of the volute tongue 2 are blocked by oil, the volute tongue 2 can be removed from the volute body 1 for easy cleaning or replacement by the user, thus replacing the fan volute with a new one. This ensures the sound absorption effect of the volute tongue 2 and reduces the user's living costs.

[0088] Furthermore, the volute tongue 2 and the muffler 3 are detachably connected. The volute tongue 2 and the muffler 3 can be connected by means of plugging, snapping, bonding, threaded connection, etc.

[0089] like Figure 3 and Figure 5 As shown, the muffler 3 is a columnar structure. A stud is provided in the cavity 204 of the volute tongue 2. The muffler 3 is provided with a screw hole that matches the stud. The stud is inserted into the screw hole, and the muffler 3 is connected to the volute tongue 2. When it is necessary to remove the muffler 3, it is only necessary to pull the muffler 3 out of the stud on the volute tongue 2, which is simple and convenient.

[0090] The sound-absorbing part 3 of the present invention is detachably connected to the volute tongue 2. When the sound-absorbing part 3 is blocked by oil, the sound-absorbing part 3 can be removed separately, which is convenient for users to clean or replace. This not only ensures the sound absorption effect of the volute tongue 2, but also reduces the user's living costs.

[0091] Another object of the present invention is to provide a range hood having the aforementioned noise-reducing fan casing.

[0092] The present invention provides a range hood with the aforementioned noise-reducing fan casing, which can effectively reduce the noise generated by the range hood fan, reduce the harm of noise to the user's body during use, protect the user's physical and mental health, and bring the user a good living experience.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A noise reducing fan volute comprising a volute body, a volute tongue and a sound attenuation portion, characterized by, The cochlea includes Cochlear tongue body; A flow guide is recessed on the inner wall of the volute tongue body to guide airflow. The flow guide extends from the side near the volute body along the air outlet direction to the side near the air outlet of the volute body. The flow guide includes multiple flow guide grooves with groove structures, which are disposed on the inner wall of the volute tongue body. Multiple micropores are provided, penetrating the flow guide and the volute tongue body, for transmitting noise. The micropores are located at the bottom of the flow guide groove and are spaced apart along the extension direction of the flow guide groove. The noise-absorbing part is installed in a cavity formed on the back of the volute tongue body to absorb noise transmitted from the micropores.

2. The noise-reducing fan casing according to claim 1, characterized in that, The flow guide groove is perpendicular to the axial direction of the volute.

3. The noise-reducing fan casing according to claim 2, characterized in that, The depth of the guide channel is 2-5mm, and the width of the channel is 2-4 times the depth of the channel.

4. The noise-reducing fan casing according to claim 1, characterized in that, The flow guide is a corrugated pressed structure with the volute tongue body undulating along the axial direction of the volute shell, and the flow guide groove is the trough of the corrugated flow guide.

5. A noise-reducing fan casing according to claim 1, characterized in that, The diameter of the micropores is 0.8-1 times the width of the bottom of the guide channel.

6. A noise-reducing fan casing according to claim 5, characterized in that, The porosity of the micropores on the flow guide is not less than 50%.

7. A noise-reducing fan casing according to any one of claims 1-6, characterized in that, The structure of the noise-absorbing part matches the shape of the concave cavity formed on the back of the snail tongue body, and the noise-absorbing part fills the concave cavity.

8. A noise-reducing fan casing according to claim 7, characterized in that, The silencing part fills the cavity.

9. A noise-reducing fan casing according to claim 8, characterized in that, The sound-absorbing part is a columnar sound-absorbing cotton.

10. A noise-reducing fan casing according to any one of claims 1-6, characterized in that, The side of the volute tongue facing the inside of the volute shell and / or the outside of the sound-absorbing part are coated with an oil-resistant coating.

11. A noise-reducing fan casing according to any one of claims 1-6, characterized in that, The volute tongue and the volute body are detachably connected.

12. A noise-reducing fan casing according to claim 11, characterized in that, The volute tongue and the volute body are connected by screws.

13. A noise-reducing fan casing according to any one of claims 1-6, characterized in that, The volute tongue and the sound-absorbing part are detachably connected.

14. A range hood, characterized in that, It has a noise-reducing fan volute as described in any one of claims 1-13.

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