Blade, centrifugal impeller, centrifugal fan and extractor hood

Abstract

The application provides a kind of blade, centrifugal impeller, centrifugal fan and range hood, blade includes the first arc part and second arc part connected, blade has air inlet end and air outlet end, air inlet end is located at the end of first arc part away from second arc part, air outlet end is located at the end of second arc part away from first arc part, the center of first arc part and the center of second arc part are located at the same side of blade, the first arc radius of first arc part is R1, the second arc radius of second arc part is R2, the first central angle of first arc part is alpha1, the second central angle of second arc part is alpha2, wherein, 1.5 <= R2 / R1 <= 3, 60 DEG <= alpha1 <= 75 DEG, and 40 DEG <= alpha2 <= 50 DEG.The centrifugal impeller provided by the application can effectively reduce the generation of airflow separation and vortex phenomenon by setting the above-mentioned blade, thereby improving the performance of the centrifugal impeller and reducing the noise during work.

Description

Technical Field

[0001] This invention relates to the field of range hood technology, and more specifically, to a blade, a centrifugal impeller, a centrifugal fan, and a range hood. Background Technology

[0002] Range hoods can draw in cooking fumes and steam and expel them outdoors using a centrifugal fan. However, existing centrifugal fans are prone to airflow separation and vortex formation during operation, which can lead to airflow collisions and generate significant noise. Additionally, the increased air pressure attenuation can reduce the effectiveness of smoke extraction. Summary of the Invention

[0003] The present invention provides a blade, a centrifugal impeller, a centrifugal fan, and a range hood to improve at least one of the above-mentioned technical problems.

[0004] The embodiments of the present invention achieve the above objectives through the following technical solutions.

[0005] In a first aspect, embodiments of the present invention provide a blade for a centrifugal impeller. The blade includes a first arc portion and a second arc portion connected to each other. The blade has an air inlet end and an air outlet end. The air inlet end is located at the end of the first arc portion away from the second arc portion, and the air outlet end is located at the end of the second arc portion away from the first arc portion. The center of the first arc portion and the center of the second arc portion are located on the same side of the blade. The first arc radius of the first arc portion is R1, the second arc radius of the second arc portion is R2, the first central angle of the first arc portion is α1, and the second central angle of the second arc portion is α2. Wherein, 1.5≦R2 / R1≦3, 60°≦α1≦75°, and 40°≦α2≦50°.

[0006] Secondly, the present invention also provides a centrifugal impeller, which includes a turntable and a plurality of blades provided in the first aspect. The turntable has a rotation axis, and the plurality of blades are arranged at intervals around the rotation axis. The air inlet ends of the plurality of blades are close to the rotation axis, and the air inlet ends of the plurality of blades are away from the rotation axis. An air duct is formed between each pair of adjacent blades.

[0007] Thirdly, the present invention also provides a centrifugal fan, which includes a housing, a driver, and a centrifugal impeller provided in the second aspect. The housing is provided with a wind chamber, an air inlet, and an air outlet. The air outlet is connected to the air inlet through the wind chamber. The centrifugal impeller is rotatably installed in the wind chamber. The driver is driven by the turntable of the centrifugal impeller.

[0008] Fourthly, the present invention also provides a range hood, which includes a housing and a centrifugal fan provided in the third aspect. The housing is provided with an air inlet chamber, the centrifugal fan is installed inside the housing, and the air duct is connected to the air inlet chamber.

[0009] The blades, centrifugal impeller, centrifugal fan, and range hood provided by the embodiments of the present invention, by arranging multiple blades in the centrifugal impeller at intervals around the rotation axis, with the air inlet ends of the multiple blades close to the rotation axis and the air inlet ends of the multiple blades away from the rotation axis, and forming an air duct between each pair of adjacent blades, since the curvature of the first arc portion of the blade is greater than the curvature of the second arc portion, and at the same time, the blade satisfies the following relationships: 1.5≦R2 / R1≦3, 60°≦α1≦75°, and 40°≦α2≦50°, it can be ensured that the radius and central angle parameters of the two arc portions of the blade are designed within a more reasonable range, so that the air duct forms a double acceleration flow channel, which can effectively reduce the phenomenon of airflow separation and vortex in the air duct, not only reducing the noise during operation, but also reducing the attenuation of wind pressure, thereby effectively improving the performance of the centrifugal impeller. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0011] Figure 1 A longitudinal cross-sectional view of a range hood provided in an embodiment of the present invention is shown.

[0012] Figure 2 It shows Figure 1 A longitudinal cross-sectional view of the centrifugal fan in a range hood.

[0013] Figure 3 It shows Figure 1 A cross-sectional view of the centrifugal fan in a range hood.

[0014] Figure 4 It shows Figure 2 A schematic diagram of the impeller structure in a range hood.

[0015] Figure 5 It shows Figure 4 A schematic diagram of the profile of a single blade in a centrifugal impeller.

[0016] Figure 6 It shows Figure 4 A schematic diagram of the profile of two adjacent blades in a centrifugal impeller.

[0017] Figure 7 It shows Figure 4 The simulation diagram shows the comparison of airflow in the duct of the centrifugal impeller with that in the duct of the existing technology during the flow process. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0020] Please see Figure 1 This invention provides a range hood 30, which includes a housing 31 and a centrifugal fan 20. The housing 31 is provided with an air inlet 311, and the centrifugal fan 20 is installed inside the housing 31.

[0021] When the range hood 30 is working, it can draw in the oil fumes and water vapor generated during cooking through the air inlet 311 and exhaust the drawn-in oil fumes and water vapor outdoors through the centrifugal fan 20.

[0022] Please see Figure 2 and Figure 3 In this embodiment, the centrifugal fan 20 includes a housing 21, a driver 22, and a centrifugal impeller 23. The housing 21 has an air chamber 211 and an air outlet 212 communicating with the air chamber 211. The centrifugal impeller 23 is rotatably mounted in the air chamber 211, and the driver 22 is driven by the centrifugal impeller 23. The air chamber 211 is connected to the air inlet 311 of the casing 31. When the centrifugal impeller 23 is working, it can generate a suction force in the air inlet 311, so oil fumes, water vapor, etc. can enter the air chamber 211 through the air inlet 311.

[0023] In this embodiment, the outer casing 21 can be a volute, which guides and diffuses the airflow. Specifically, the volute has a helical vortex chamber that connects the air chamber 211 to the air outlet 212. Besides collecting oil, the volute also allows the fumes to be smoothly discharged outdoors, achieving the effects of purifying oil fumes and improving ventilation. When the range hood 30 is working, the centrifugal impeller 23 rotates rapidly. The centrifugal force generated during this rapid rotation can quickly expel oil fumes and water vapor from the air chamber 211 through the air outlet 212.

[0024] Please see Figure 4The centrifugal impeller 23 includes a rotating disk 231 and multiple blades 232. The rotating disk 231 has a rotation axis O, which can be the center line of the rotating disk 231. The multiple blades 232 are spaced apart around the rotation axis O, and an air duct 233 is formed between each two adjacent blades 232. The driver 22 is drivenly connected to the rotating disk 231. The rotation shaft of the driver 22 can be directly connected to the rotating disk 231, or it can be driven by the rotating disk 231 through a transmission structure.

[0025] In this embodiment, multiple blades 232 are fixed on the same side of the turntable 231. The multiple blades 232 can be arranged around the rotation axis O, and the multiple blades 232 can be evenly spaced. Each blade 232 has a length direction, and the length direction of each blade 232 can be approximately parallel to the rotation axis O.

[0026] In this embodiment, the centrifugal impeller 23 may further include an end ring 234, which may be approximately circular in shape. The end ring 234 and the turntable 231 are spaced apart relative to each other, and the two may be spaced apart relative to each other in a direction approximately parallel to the rotation axis O. Multiple blades 232 may be fixed between the turntable 231 and the end ring 234, thus ensuring the stability of each blade 232. The end ring 234 can provide protection for the blades 232, preventing the blades 232 from colliding with external structures and deforming.

[0027] Please see Figure 3 and Figure 4 In this embodiment, multiple blades 232 collectively define an air inlet space 235, meaning the air inlet space 235 is located within the area defined by the multiple blades 232. The air inlet space 235 is connected to the air chamber 211, allowing air entering from the air inlet 311 to enter the air inlet space 235 via the air chamber 211. When the centrifugal impeller 23 rotates rapidly, the centrifugal force it generates can quickly draw the air from the air inlet space 235 into the air duct 233, and accelerate the airflow through the air duct 233 of the centrifugal impeller 23, thereby quickly discharging it from the air outlet 212.

[0028] Please see Figure 4 and Figure 5In this embodiment, the profile of the blade 232 includes two arc segments with different radii and central angles. Specifically, the blade 232 includes a first arc segment 2321 and a second arc segment 2322 connected to each other, and the blade 232 has an air inlet end 2323 and an air outlet end 2324. The air inlet end 2323 is located at the end of the first arc segment 2321 away from the second arc segment 2322, and the air outlet end 2324 is located at the end of the second arc segment 2322 away from the first arc segment 2321. The air inlet ends 2323 of multiple blades 232 are close to the rotation axis O, and multiple blades 232 can be arranged facing the rotation axis O, while the air inlet ends 2323 of multiple blades 232 are away from the rotation axis O. The center of the first arc segment 2321 and the center of the second arc segment 2322 are located on the same side of the blade 232. Each blade 232 is installed in the same way, and the bending directions of two adjacent blades 232 are approximately the same.

[0029] By placing the center of the first arc portion 2321 and the center of the second arc portion 2322 on the same side of the blade 232, the bending directions of the first arc portion 2321 and the second arc portion 2322 are kept consistent, that is, the first arc portion 2321 and the second arc portion 2322 both bend towards the same side of the blade 232. This allows the air duct 233 between two adjacent blades 232 to be approximately arc-shaped.

[0030] In this embodiment, the first arc radius of the first arc portion 2321 is R1, the second arc radius of the second arc portion 2322 is R2, the first central angle of the first arc portion 2321 is α1, and the second central angle of the second arc portion 2322 is α2, wherein 1.5≦R2 / R1≦3, 60°≦α1≦75°, and 40°≦α2≦50°. Preferably, 2≦R2 / R1≦3, 70°≦α1≦75°, and 45°≦α2≦50°. Therefore, the curvature of the first arc portion 2321 is greater than the curvature of the second arc portion 2322.

[0031] For example, R2 / R1 = 2, R2 / R1 = 2.2, R2 / R1 = 2.4, R2 / R1 = 2.6, or R2 / R1 = 2.8, etc. Another example is α1 = 70°, α1 = 71°, α1 = 72°, α1 = 73°, α1 = 74°, or α1 = 75°, etc. Yet another example is α2 = 45°, α2 = 46°, α2 = 47°, α2 = 48°, α2 = 49°, or α2 = 50°, etc. These are just a few examples; adjustments can be made according to actual needs, as long as 1.5 ≤ R2 / R1 ≤ 3, 60° ≤ α1 ≤ 75°, and 40° ≤ α2 ≤ 50° are met.

[0032] Please see Figures 4 to 6In this embodiment, the air duct 233 includes a first flow channel 2331 and a second flow channel 2332 that are connected to each other. The first flow channel 2331 is formed between the first arcuate portions 2321 of two adjacent blades 232, and the second flow channel 2332 is formed between the second arcuate portions 2322 of two adjacent blades 232. Each air duct 233 has an air inlet 2333 and an air outlet 2334. The air outlet 2334 is connected to the air intake space 235 through the air inlet 2333. The air inlet 2333 is located at the end of the first flow channel 2331 away from the second flow channel 2332, and the air outlet 2334 is located at the end of the second flow channel 2332 away from the first flow channel 2331. The first flow channel 2331 and the second flow channel 2332 serve as acceleration channels for the air duct 233. The airflow is accelerated after entering the first flow channel 2331, and it is accelerated again after entering the second flow channel 2332 from the first flow channel 2331, thus achieving a dual acceleration effect of the air duct 233 on the airflow.

[0033] In some embodiments, when R2 / R1 = 3, this makes the second arc portion 2322 have a longer radius dimension. Therefore, the second flow channel 2332 of the air duct 233 can form a uniform and narrow air passage structure. When air enters the second flow channel 2332 from the first flow channel 2331 and flows through the entire second flow channel 2332, there is basically no phenomenon of air flow separation and vortex. The dynamic pressure of the air at the air outlet 2334 of the air duct 233 is effectively converted into static pressure, so that the airflow can flow out from the air outlet 2334 at a faster speed.

[0034] In some implementations, α 1＝ 75°, α 2＝ 50°. This design gives the first flow channel 2331 a longer flow path, allowing the airflow entering from the air inlet 2333 to be significantly accelerated within the first flow channel 2331. At the same time, it makes the second flow channel 2332 of the air duct 233 more elongated, further accelerating the airflow after it enters the second flow channel 2332 from the first flow channel 2331. This achieves a dual acceleration effect on the airflow throughout the air duct 233, reducing airflow separation and vortex generation, improving fan performance, and reducing noise.

[0035] In this embodiment, the first arc portion 2321 has a first contour arc 2326, the second arc portion 2322 has a second contour arc 2327, and the first contour arc 2326 and the second contour arc 2327 have a connection point P. The first contour arc 2326 and the second contour arc 2327 can be the outer contour lines of the corresponding arc portion of the blade 232. The first contour arc 2326 and the second contour arc 2327 have a common tangent X at the connection point P, that is, the common tangent X between the first arc portion 2321 and the second arc portion 2322 is located at the connection between the first arc portion 2321 and the second arc portion 2322. This allows for a smooth connection between the first arc portion 2321 and the second arc portion 2322, effectively reducing the airflow resistance at the connection between the first arc portion 2321 and the second arc portion 2322. This makes it less likely for the airflow to separate or generate eddies, allowing the airflow to smoothly enter the second flow channel 2332 and be continuously accelerated after being accelerated through the first flow channel 2331.

[0036] In this embodiment, the connection point P of the multiple blades 232 is approximately located on the same intermediate ring Y1. By placing the connection point P of the multiple blades 232 on the same intermediate ring Y1, it can be ensured that the connection between the first flow channel 2331 and the second flow channel 2332 of the air duct 233 is approximately on the same intermediate ring Y1. In this way, after the airflow flows in from the first flow channel 2331, the airflow in each air duct 233 can be accelerated at the position of the intermediate ring Y1 simultaneously, thereby ensuring that each air duct 233 has approximately the same acceleration effect on the airflow.

[0037] Please continue reading. Figures 4 to 6 In this embodiment, each blade 232 has a first endpoint d1 at its air inlet end 2323, which is located on the end face of the air inlet end 2323 away from the air outlet end 2324. The air outlet end 2324 has a second endpoint d2, which is located on the end face of the air outlet end 2324 away from the air inlet end 2323. The first endpoints d1 of the multiple blades 232 are approximately located in the same inner ring Y2, and the second endpoints d2 of the multiple blades 232 are approximately located in the same outer ring Y3. The middle ring Y1 is located between the inner ring Y2 and the outer ring Y3. This not only ensures that each blade 232 is accurately installed in its corresponding position, but also guarantees that the flow length of the first flow channel 2331 of the multiple air ducts 233 is approximately the same. At the same time, the flow length of the second flow channel 2332 of the multiple air ducts 233 is also approximately the same, and the shape of each air duct 233 is approximately the same, ensuring that the multiple air ducts 233 have consistency. This reduces the phenomenon of airflow separation and vortex generation in each air duct 233, improves the overall performance of the centrifugal fan 20, and significantly reduces noise.

[0038] In some embodiments, there is a first gap L1 between the middle ring Y1 and the outer ring Y3, and a second gap L2 between the middle ring Y1 and the inner ring Y2, wherein the first gap L1 is smaller than the second gap L2. By making the gap between the middle ring Y1 and the outer ring Y3 shorter, the second flow channel 2332 of the air duct 233 becomes more elongated, which can further reduce airflow separation and vortices. The airflow can be continuously accelerated within the second flow channel 2332, and the air velocity can reach its maximum at the air outlet 2334.

[0039] In some implementations, such as Figure 5 and Figure 6 As shown, the blade 232 and the inner ring Y2 have an inlet mounting angle β1, where 45°≦β1≦50°, for example, β1=45°, β1=46°, β1=47°, β1=48°, β1=49° or β1=50°. Here, β1 is the angle formed between the first tangent X and the second tangent X, where the first tangent X is the tangent line of the first arc portion 2321 at the first endpoint d1, and the second tangent line is the tangent line of the inner ring Y2 at the first endpoint d1. Since the airflow does not enter the air duct 233 perpendicular to the air inlet 2333 when the centrifugal impeller 23 rotates rapidly, the airflow will have a certain impact on the first arc portion 2321 of the blade 232. Therefore, the larger the inlet installation angle β1, the greater the impact of the airflow on the first arc portion 2321, and the greater the velocity loss of the air at the air inlet 2333. Therefore, by setting the inlet installation angle β1 between 45° and 50°, the velocity loss of the air by the first arc portion 2321 can be significantly reduced, and the impact of the airflow on the first arc portion 2321 can be reduced, further reducing noise.

[0040] In some embodiments, an outlet installation angle β2 exists between the blade 232 and the outer ring Y3, wherein 160°≦β2≦170°, for example, β2=160°, β2=162°, β2=164°, β2=166°, β2=168°, or β2=170°. Here, β2 is the angle between the third tangent and the fourth tangent, where the third tangent is the tangent of the second arc portion 2322 at the second end point d2, and the fourth tangent is the tangent of the outer ring Y3 at the second end point d2. By controlling the outlet installation angle β2 between 160° and 170°, the second flow channel 2332 becomes more elongated and gentler, preventing significant impact on the second arc portion 2322 of the blade 232 when airflow passes through the second flow channel 2332, reducing noise, and allowing the airflow to flow out of the second flow channel 2332 at maximum speed along the second arc portion 2322.

[0041] In some embodiments, a plurality of inscribed circles C are present between two adjacent blades 232. The diameter of the plurality of inscribed circles C gradually increases and then gradually decreases from the air inlet end 2323 toward the air outlet end 2324, wherein the inscribed circle C located at the air outlet end 2324 has the smallest diameter. For example, the plurality of inscribed circles C located in the first flow channel 2331 gradually increase and then decrease from the position of the air inlet 2333 to the second flow channel 2332, so that the cross-sectional area of ​​the first flow channel 2331 gradually increases and then decreases from the position of the air inlet 2333 to the position of the second flow channel 2332; the plurality of inscribed circles C located in the second flow channel 2332 gradually decrease from the position near the first flow channel 2331, so that the cross-sectional area of ​​the second flow channel 2332 gradually decreases from the position near the first flow channel 2331 toward the air outlet 2334.

[0042] It should be noted that each inscribed circle C is tangent to the corresponding positions of two adjacent blades 232. For example, inscribed circle C1 is tangent to the position of the first arc portion 2321 of blade 232 at the air inlet 2333, inscribed circle C2 is tangent to the middle position of the first arc portion 2321, inscribed circle C3 is tangent to the position where the first arc portion 2321 and the second arc portion 2322 connect, inscribed circle C4 is tangent to the middle position of the second arc portion 2322, and inscribed circle C5 is the inscribed circle of the second arc portion 2322 at the air outlet 2334. In this system, the diameter of inscribed circle C1 is smaller than the diameter of inscribed circle C2, the diameter of inscribed circle C3 is smaller than the diameter of inscribed circle C2, and the diameters of inscribed circles C4 and C5 are both smaller than the diameter of inscribed circle C3, but the diameter of inscribed circle C5 is smaller than the diameter of inscribed circle C4. Inscribed circle C5 is the smallest inscribed circle among multiple inscribed circles. Since the cross-sectional area of ​​the first flow channel 2331 increases and then decreases from the air inlet 2333 to the second flow channel 2332, the airflow velocity within the first flow channel 2331 first increases and then decreases. This allows the airflow to pass smoothly through the junction of the first arc portion 2321 and the second arc portion 2322. Since the cross-sectional area of ​​the second flow channel 2332 gradually decreases from the position near the first flow channel 2331 toward the air outlet 2334, the second flow channel 2332 becomes a tapered flow channel structure. Therefore, the airflow can be continuously accelerated in the second flow channel 2332, the airflow velocity gradually increases, and finally the airflow can flow out at the air outlet 2334 at the fastest velocity. The air duct 233 can serve as a dual acceleration flow channel for the airflow, effectively suppressing the air pressure attenuation in the air duct 233.

[0043] Please see Figure 7 , Figure 7 The left-hand diagram shows a simulation of the airflow within the duct of a centrifugal impeller in existing technology. Figure 7The diagram on the right shows a simulation of the airflow within the duct 233 of the centrifugal impeller 23 provided by the present invention. Due to the excessively large range of the first central angle α1 of the first arc portion in the prior art, and the excessively large ratio of R2 / R1, simulation revealed that when the airflow passes through the duct of the centrifugal impeller in the prior art, obvious airflow separation and vortex phenomena will occur. This not only leads to greater noise from the centrifugal fan in the prior art, but also easily causes the air pressure in the duct to decrease too quickly, resulting in a reduction in the performance of the centrifugal fan and a poor smoke extraction effect of the existing range hood.

[0044] Compared to existing centrifugal impellers, this invention designs the radii and central angle parameters of the two arc segments of the blades 232 of the centrifugal impeller 23 within a more reasonable range. Specifically, the blades 232 satisfy the following relationships: 1.5≦R2 / R1≦3, 60°≦α1≦75°, and 40°≦α2≦50°. Figure 7 As can be clearly seen from the right-hand diagram, when the airflow passes through the air duct 233 of the centrifugal impeller 23 provided in this embodiment of the invention, almost no airflow separation or vortex phenomenon occurs. Obviously, the centrifugal impeller 23 provided by the present invention has better performance and noise reduction capability than the centrifugal impellers in the prior art.

[0045] The centrifugal impeller 23 provided in this embodiment of the invention has a large first central angle α1 of the first arc portion 2321, but a small first arc radius R1, resulting in a large curvature of the first arc portion 2321. This makes the position where the blade 232 bends the most approximately located at the connection between the first arc portion 2321 and the second arc portion 2322. As a result, the cross-sectional area of ​​the air duct 233 near the connection between the first arc portion 2321 and the second arc portion 2322 is the largest. Therefore, the cross-sectional area of ​​the middle part of the air duct 233 is larger than the cross-sectional area of ​​the air duct 233 at the air inlet 2333 and the air outlet 2334. Therefore, after the airflow enters from the air inlet 2333, it gradually accelerates and then decelerates through the first flow channel 2331, so that the airflow smoothly enters the second flow channel 2332 from the first flow channel 2331 and continues to accelerate through the second flow channel 2332. The second central angle α2 of the second arc portion 2322 is relatively small, the radius R2 of the second arc portion 2322 is relatively large, and the curvature of the second arc portion 2322 is reduced. This makes the second flow channel 2332 of the air duct 233 long and narrow. Therefore, the cross-sectional area of ​​the second flow channel 2332 gradually decreases from the position near the first flow channel 2331 toward the air outlet 2334. The air entering the second flow channel 2332 gradually accelerates, thereby effectively reducing airflow separation and vortex generation, improving the performance of the entire centrifugal fan 20, and reducing noise.

[0046] In summary, by arranging multiple blades 232 in the centrifugal impeller 23 at intervals around the rotation axis O, with the air inlet end 2323 of the multiple blades 232 close to the rotation axis O and the air inlet end 2323 of the multiple blades 232 away from the rotation axis O, an air duct 233 is formed between each pair of adjacent blades 232. Since the curvature of the first arc portion 2321 of the blade 232 is greater than the curvature of the second arc portion 2322, and the blade 232 satisfies the following relationships: 1.5≦R2 / R1≦3, 60°≦α1≦75°, and 40°≦α2≦50°, the radius and central angle parameters of the two arc portions of the blade 232 can be designed within a more reasonable range. This allows the air duct 233 to form a dual-acceleration flow channel, which can effectively reduce the phenomenon of airflow separation and vortex generation in the air duct 233. This not only reduces noise during operation but also reduces the attenuation of air pressure, thereby effectively improving the performance of the centrifugal impeller 23.

[0047] In this invention, unless otherwise explicitly specified or limited, the terms "installation," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can be a mechanical connection; they can be a direct connection or an indirect connection via an intermediate medium; they can be a connection within two components; they can be merely surface contact; or a surface contact connection via an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0048] Furthermore, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as referring to specific or particular structures. The description of "some embodiments" means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this invention, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate different embodiments or examples described in this invention, as well as the features of different embodiments or examples.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A centrifugal impeller, characterized in that, The centrifugal impeller includes a turntable and multiple blades; each blade includes a first arc portion and a second arc portion connected to each other, each blade has an air inlet end and an air outlet end, the air inlet end is located at the end of the first arc portion away from the second arc portion, the air outlet end is located at the end of the second arc portion away from the first arc portion, and the center of the first arc portion and the center of the second arc portion are located on the same side of the blade. The first arc radius of the first arc portion is R1, the second arc radius of the second arc portion is R2, the first central angle of the first arc portion is α1, and the second central angle of the second arc portion is α2, wherein 1.5≦R2 / R1≦3, 60°≦α1≦75°, and 40°≦α2≦50°; The turntable has a rotation axis, and a plurality of blades are spaced apart around the rotation axis. The air inlet ends of the plurality of blades are close to the rotation axis, and the air outlet ends of the plurality of blades are away from the rotation axis. An air duct is formed between each pair of adjacent blades. There are a plurality of inscribed circles between each pair of adjacent blades, and the diameter of the plurality of inscribed circles gradually increases and then gradually decreases from the air inlet end toward the air outlet end. The air duct includes a first flow channel and a second flow channel that are connected to each other. The first flow channel is formed between the first arc portion of two adjacent blades. The plurality of inscribed circles in the first flow channel gradually increase and then decrease from the air inlet end to the position of the second flow channel, so that the cross-sectional area of ​​the first flow channel gradually increases and then decreases from the air inlet end to the position of the second flow channel. The second flow channel is formed between the second arc portion of two adjacent blades; the plurality of inscribed circles located in the second flow channel gradually decrease from the position near the first flow channel to the air outlet end, so that the cross-sectional area of ​​the second flow channel gradually shrinks from the position near the first flow channel toward the air outlet end.

2. The centrifugal impeller according to claim 1, characterized in that, The first arc portion has a first contour arc, the second arc portion has a second contour arc, the first contour arc and the second contour arc have a connection point, and the first contour arc and the second contour arc have a common tangent at the connection point.

3. The centrifugal impeller according to claim 2, characterized in that, The connection points of the multiple blades are located in the same intermediate ring.

4. The centrifugal impeller according to claim 3, characterized in that, Each blade has a first end point at its air inlet end and a second end point at its air outlet end. The first ends of multiple blades are located in the same inner ring, and the second ends of multiple blades are located in the same outer ring. The middle ring is located between the inner ring and the outer ring.

5. The centrifugal impeller according to claim 4, characterized in that, There is a first gap between the middle ring and the outer ring, and a second gap between the middle ring and the inner ring, wherein the first gap is smaller than the second gap.

6. The centrifugal impeller according to claim 4, characterized in that, The blade and the inner ring have an inlet mounting angle β1, wherein 45°≦β1≦50°.

7. The centrifugal impeller according to claim 6, characterized in that, The blade and the outer ring have an outlet installation angle β2, wherein 160°≦β2≦170°.

8. The centrifugal impeller according to any one of claims 1 to 7, characterized in that, Of the plurality of inscribed circles, the one located at the air outlet has the smallest diameter.

9. A centrifugal fan, characterized in that, The centrifugal fan includes a housing, a driver, and a centrifugal impeller as described in any one of claims 1 to 8. The housing is provided with a wind chamber and an air outlet communicating with the wind chamber. The air outlet is communicating with the wind chamber. The centrifugal impeller is rotatably mounted in the wind chamber. The driver is in drive cooperation with the turntable of the centrifugal impeller.

10. A range hood, characterized in that, The device includes a housing and a centrifugal fan as described in claim 9, wherein the housing has an air inlet chamber, the centrifugal fan is installed inside the housing, and the air inlet chamber is in communication with the air inlet chamber.

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