Centrifugal impeller, centrifugal fan and equipment using centrifugal fan

Abstract

The utility model belongs to the technical field of fans, and discloses a centrifugal impeller, a centrifugal fan and equipment using the centrifugal fan, blades with non-equal-thickness blade-shaped structures are adopted, the thickness of the blades is gradually increased from inside to outside in the radial direction of a middle disc, and the width of an airflow channel is gradually increased and then gradually reduced from inside to outside in the radial direction of the middle disc, so that the centrifugal impeller is formed. The width near the air outlet end of the airflow channel is slowly reduced, the airflow channel between every two adjacent blades forms an effective airflow buffering area, airflow can better flow in the airflow channel between every two adjacent blades, vortex generation of the pressure face is reduced, noise is lowered, and meanwhile the service life of the blades is prolonged. The power capability of the centrifugal impeller at a high rotating speed is increased, so that the static pressure capability of the centrifugal impeller is higher.

Description

Technical Field

[0001] This utility model relates to the field of fan technology, and in particular to a centrifugal impeller, a centrifugal fan, and equipment using the centrifugal fan. Background Technology

[0002] For equipment that uses centrifugal fans, such as gas water heaters, the main function of the centrifugal fan is to extract the high-temperature flue gas from the combustion chamber.

[0003] To increase air intake, existing centrifugal fans are usually equipped with a main air inlet and a secondary air inlet. The impeller is mostly a double-blade impeller, that is, there are blades on both sides of the middle plate of the impeller. However, the blades of existing double-blade impellers are generally designed with equal thickness, and an airflow channel is formed between two adjacent blades. When the centrifugal impeller rotates, the airflow passes through the airflow channel, which generates a lot of noise and seriously affects the user experience; moreover, the airflow loss is relatively large. Utility Model Content

[0004] One of the technical problems solved by this utility model is to provide a centrifugal impeller that can reduce noise, reduce airflow loss, increase the working capacity of the centrifugal impeller, and make the static pressure capacity of the centrifugal impeller higher.

[0005] The second technical problem solved by this utility model is to provide a centrifugal fan that can reduce noise, reduce airflow loss, increase the working capacity of the centrifugal fan, and make the static pressure capacity of the centrifugal fan higher.

[0006] The third technical problem solved by this utility model is to provide a device that uses a centrifugal fan, which can reduce noise, increase the working capacity of the centrifugal fan, and make the static pressure capacity of the centrifugal fan higher.

[0007] The first technical problem mentioned above is solved by the following technical solution:

[0008] A centrifugal impeller includes a central disk and multiple blades. Multiple blades are arranged at intervals along the circumference of the central disk on both axial sides. The thickness of the blades gradually increases from the inside to the outside along the radial direction of the central disk.

[0009] An airflow channel is formed between two adjacent blades located on the same side of the central disk. The width of the airflow channel gradually increases and then gradually decreases from the inside to the outside along the radial direction of the central disk. The arc length of the airflow channel along the circumference of the central disk is the width of the airflow channel.

[0010] The maximum heights of the blades on both sides of the central disk are different.

[0011] The centrifugal impeller described in this utility model has the following advantages compared with the prior art:

[0012] In this invention, the blades are designed with a non-uniform thickness blade structure, and the thickness of the blades gradually increases from the inside to the outside along the radial direction of the central disk. The width of the airflow channel gradually increases and then gradually decreases from the inside to the outside along the radial direction of the central disk. This makes the width of the airflow channel near the outlet end slowly decrease, and the airflow channel between two adjacent blades forms an effective airflow buffer area, allowing the airflow to flow better in the airflow channel between two adjacent blades. This reduces the generation of eddies on the pressure surface, reduces noise, and increases the work capacity of the centrifugal impeller at high speed, making the static pressure capacity of the centrifugal impeller higher.

[0013] By limiting the height of the blades on both sides of the central plate to be different, the centrifugal impeller is set asymmetrically with respect to the central plate, thereby increasing the natural frequency of the centrifugal impeller. This prevents the noise frequency of the equipment using the centrifugal fan from reaching the natural frequency of the centrifugal impeller, thus avoiding resonance of the centrifugal impeller and reducing the noise of the centrifugal fan during operation. This, in turn, reduces the noise of the equipment using the centrifugal fan and improves the user experience.

[0014] In one embodiment, the blade includes a pressure surface and a suction surface arranged circumferentially opposite to each other along the middle disk. The projection of the pressure surface in a preset plane includes a pressure arc, and the projection of the suction surface in the preset plane includes a suction arc. The preset plane is perpendicular to the axial direction of the middle disk.

[0015] The end point of the pressure arc away from the central axis of the middle plate is the first outer end point, and the end point of the suction arc away from the central axis of the middle plate is the second outer end point.

[0016] The arc length of the first outer endpoint and the second outer endpoint between two adjacent blades along the circumference of the central disk is S1. Among the adjacent blades, the arc length of the second outer endpoint corresponding to one blade and the second outer endpoint corresponding to the other blade along the circumference of the central disk is S2, where 0.45 < S1 / S2 ≤ 0.57.

[0017] In one embodiment, the circle represented by the inner diameter of the blade is the inner circle, and the extension line of the suction arc near the central axis of the middle disk intersects the inner circle at a first intersection point. The line connecting the first intersection point and the projection point of the central axis of the middle disk on the preset plane is the first connecting line.

[0018] The circle represented by the outer diameter of the blade is the outer circle. The end of the pressure arc away from the central axis of the middle disk intersects the outer circle at a second point. The line connecting the second intersection point and the projection point is the second connecting line. The angle between the first connecting line and the second connecting line corresponding to any blade is α.

[0019] The inlet angle of the suction surface is a1, the inlet angle of the pressure surface is a2, the outlet angle of the suction surface is b1, the outlet angle of the pressure surface is b2, a1>a2, b1+1.5×α<b2<b1+3×α.

[0020] In one embodiment, the tangent line that is tangent to the pressure arc and passes through the projection point is a preset tangent line, and the angle between the preset tangent line corresponding to any blade and the second connecting line is β; 0.6≤β / α≤0.8.

[0021] In one embodiment, the blade located on one side of the central disk is a first blade, and the blade located on the other side of the central disk is a second blade, and a plurality of first blades and a plurality of second blades are arranged in a one-to-one correspondence;

[0022] At least a portion of the first blade and the corresponding second blade are arranged circumferentially offset along the central disk; and / or, at least a portion of the first blade and the corresponding second blade are arranged axially opposite each other along the central disk.

[0023] In one embodiment, the maximum height of the blade located on one side of the axial direction of the disk is h1, and the maximum height of the blade located on the other side of the axial direction of the disk is h2, where 1 < h1 : h2 ≤ 1.7.

[0024] The second technical problem mentioned above is solved by the following technical solution:

[0025] A centrifugal fan includes a motor, a volute, and a centrifugal impeller as provided in any of the above embodiments. The centrifugal impeller is rotatably mounted inside the volute. The maximum height of the blade located on one side of the axial direction of the central disk is h1, and the maximum height of the blade located on the other side of the axial direction of the central disk is h2, where 1 < h1 : h2 ≤ 1.7. The blade with the maximum height h2 and the motor are located on the same side of the central disk, and the output shaft of the motor is connected to the central disk to drive the centrifugal impeller to rotate.

[0026] Compared with the prior art, the centrifugal fan described in this utility model has the following beneficial effects:

[0027] The centrifugal fan includes the aforementioned centrifugal impeller, with blades configured as non-uniform thickness blades. The blade thickness gradually increases from the inside to the outside along the radial direction of the central disk, and the width of the airflow channel gradually increases and then gradually decreases from the inside to the outside along the radial direction of the central disk. This causes the width of the airflow channel near the outlet end to decrease slowly, and the airflow channel between two adjacent blades forms an effective airflow buffer area, allowing the airflow to flow better within the airflow channel between two adjacent blades. This reduces the generation of eddies on the pressure surface, lowers noise, and increases the work capacity of the centrifugal impeller at high speeds, resulting in a higher static pressure capacity of the centrifugal impeller.

[0028] By limiting 1 < h1: h2 < 1.7, the centrifugal impeller is asymmetrically set about the central disk, thereby increasing the natural frequency of the centrifugal impeller. This prevents the noise frequency of the equipment using the centrifugal fan from reaching the natural frequency of the centrifugal impeller, thus avoiding resonance of the centrifugal impeller and reducing the noise of the centrifugal fan during operation. This, in turn, reduces the noise of the equipment using the centrifugal fan and improves the user experience.

[0029] In one embodiment, the volute has an air inlet, the air inlet and the motor are located on opposite sides of the central plate, and the central plate is provided with a plurality of air guide holes arranged at intervals along its circumference.

[0030] Alternatively, the volute has a first air inlet and a second air inlet, the first air inlet and the second air inlet being located on opposite sides of the middle plate, and the second air inlet and the motor being located on the same side of the middle plate.

[0031] In one embodiment, the cross-sectional area of ​​the second air inlet is smaller than that of the first air inlet.

[0032] The third technical problem mentioned above is solved by the following technical solution:

[0033] Equipment that uses centrifugal fans includes the centrifugal fans described above.

[0034] Compared with the prior art, the equipment using a centrifugal fan described in this utility model has the following advantages:

[0035] The equipment using a centrifugal fan includes the aforementioned centrifugal fan, in which the blades of the centrifugal impeller are configured with a non-uniform thickness blade structure, and the thickness of the blades gradually increases from the inside to the outside along the radial direction of the central disk. The width of the airflow channel gradually increases and then gradually decreases from the inside to the outside along the radial direction of the central disk, so that the width near the outlet end of the airflow channel slowly decreases. The airflow channel between two adjacent blades forms an effective airflow buffer area, allowing the airflow to flow better within the airflow channel between two adjacent blades, reducing the generation of eddies on the pressure surface, reducing noise, and increasing the work capacity of the centrifugal impeller at high speeds, thus making the static pressure capacity of the centrifugal impeller higher.

[0036] By limiting 1 < h1: h2 < 1.7, and placing the blades and motor with a maximum height of h2 on the same side of the central disk, the centrifugal impeller is asymmetrically positioned about the central disk. This increases the natural frequency of the centrifugal impeller, ensuring that the noise frequency of the equipment using this centrifugal fan does not reach the natural frequency of the centrifugal impeller. This avoids resonance in the centrifugal impeller, thereby reducing the noise of the centrifugal fan during operation and improving the user experience. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the centrifugal fan provided in this embodiment of the utility model;

[0038] Figure 2 This is a schematic diagram of the structure of the centrifugal impeller provided in an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the blade projected onto a preset plane according to an embodiment of the present invention;

[0040] Figure 4 This is a side view of the centrifugal impeller provided in an embodiment of the present invention;

[0041] Figure 5 This is an axial schematic diagram of the blade provided in an embodiment of the present invention;

[0042] Figure 6 This is a partial schematic diagram of the blade provided in an embodiment of the present utility model;

[0043] Figure 7 yes Figure 5 A magnified view of a portion of point N in the diagram;

[0044] Figure 8 yes Figure 5 A magnified view of a portion of point M in the middle;

[0045] Figure 9 This is a cross-sectional view of the centrifugal fan provided in an embodiment of this utility model.

[0046] In the picture:

[0047] 1. Mid-plate; 2. Blade; 2a. First blade; 2b. Second blade; 21. Suction surface; 211. Suction arc; 22. Pressure surface; 221. Pressure arc; 23. Airflow channel; 24. Inner surface; 241. Inner intersection line; 25. Outer surface; 251. Outer projection; 26. Top surface;

[0048] 3. Volute; 31. Shell body; 32. Motor mounting part; 33. Connecting rib; 34. Sub-air inlet; 35. Air guide shroud; 351. First air inlet;

[0049] 4. Electric motor;

[0050] A. First outer endpoint; B. Second outer endpoint; C. First intersection point; D. Second intersection point; O. Projection point;

[0051] 10. Outer circle; 20. Inner circle;

[0052] 100. Centrifugal impeller. Detailed Implementation

[0053] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "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 application 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 application.

[0055] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0056] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0057] This utility model provides a centrifugal impeller, a centrifugal fan including the centrifugal impeller 100, and equipment using the centrifugal fan. By reducing the generation of eddies on the pressure surface of the centrifugal impeller 100, the working capacity of the centrifugal impeller 100 is increased, resulting in a higher static pressure capacity. The equipment using the centrifugal fan can be a gas-fired water heating system, such as a gas water heater, gas-fired boiler, or gas-fired heating boiler; it can also be a fume extraction system with oil fume extraction function, such as a range hood, a combined range hood and stove, or an integrated stove. In the equipment using the centrifugal fan, the centrifugal fan is mainly used as an air supply device. The equipment using the centrifugal fan is not limited to gas-fired water heating systems and fume extraction systems; it can also be other equipment that uses the aforementioned centrifugal fan as an air supply device, and is not specifically limited here.

[0058] like Figures 1 to 4 As shown, the centrifugal fan also includes a motor 4 and a volute 3. The centrifugal impeller 100 is rotatably installed inside the volute 3. The output shaft of the motor 4 is connected to the centrifugal impeller 100 to drive the centrifugal impeller 100 to rotate, so that the external airflow enters the volute 3 through the air inlet of the centrifugal fan and is sent to the air outlet of the centrifugal fan by the centrifugal impeller 100.

[0059] The centrifugal impeller 100 includes a central disk 1 and multiple blades 2. Multiple blades 2 are arranged at intervals along the circumference of the central disk 1 on both sides of the central disk 1. The thickness of the blades 2 gradually increases from the inside to the outside along the radial direction of the central disk 1. An airflow channel 23 is formed between two adjacent blades 2 on the same side of the central disk 1. The width of the airflow channel 23 gradually increases from the inside to the outside along the radial direction of the central disk 1 and then gradually decreases. The arc length of the airflow channel 23 along the circumference of the central disk 1 is the width of the airflow channel 23.

[0060] The thickness of the blade 2 gradually increases from the inside to the outside along the radial direction of the middle disk 1, and the width of the airflow channel 23 gradually increases and then gradually decreases from the inside to the outside along the radial direction of the middle disk 1. This causes the width of the airflow channel 23 near the outlet end to decrease slowly. The airflow channel 23 between two adjacent blades 2 forms an effective airflow buffer area, allowing the airflow to flow better within the airflow channel 23 between two adjacent blades 2. The airflow velocity changes slowly and the change amplitude is relatively uniform, reducing the generation of vortices on the pressure surface 22. While reducing noise, it increases the work capacity of the centrifugal impeller 100 at high speed, making the static pressure capacity of the centrifugal impeller 100 higher.

[0061] In some embodiments, the maximum heights of the blades 2 on both sides of the central disk 1 are different, making the centrifugal impeller 100 asymmetrically arranged with respect to the central disk 1. This increases the natural frequency of the centrifugal impeller 100, so that the noise frequency of the equipment using the centrifugal fan does not reach the natural frequency of the centrifugal impeller 100 during operation. This avoids resonance of the centrifugal impeller 100, thereby reducing the noise of the centrifugal fan using the centrifugal impeller 100 during operation and improving the user experience.

[0062] In some embodiments, the maximum height of the blade 2 located on one side of the axial direction of the central disk 1 is h1, and the maximum height of the blade 2 located on the other side of the axial direction of the central disk 1 is h2, where 1 < h1 : h2 < 1.7. Specifically, the output shaft of the motor 4 is connected to the central disk 1, and the motor 4 and the blade 2 with a maximum height of h2 are located on the same side of the central disk 1.

[0063] By limiting 1 < h1: h2 < 1.7, the centrifugal impeller 100 is asymmetrically set about the central disk 1, thereby increasing the natural frequency of the centrifugal impeller 100. This prevents the noise frequency of the equipment using the centrifugal fan from reaching the natural frequency of the centrifugal impeller 100, thus avoiding resonance of the centrifugal impeller 100 and reducing the noise of the centrifugal fan during operation. This, in turn, reduces the noise of the equipment using the centrifugal fan and improves the user experience.

[0064] It should be noted that the ratio of h1 to h2 can be any value between 1 and 1.7, such as any one of 1.1, 1.2, 1.3, 1.4, 1.5, or 1.6.

[0065] In some embodiments, such as Figures 2 to 6 As shown, the blade 2 includes a pressure surface 22 and a suction surface 21 arranged circumferentially opposite each other along the central disk 1. The projection of the pressure surface 22 onto a preset plane includes a pressure arc 221, and the projection of the suction surface 21 onto the preset plane includes a suction arc 211. The preset plane is perpendicular to the axial direction of the central disk 1. The endpoint of the pressure arc 221 away from the central axis of the central disk 1 is the first outer endpoint A, and the endpoint of the suction arc 211 away from the central axis of the central disk 1 is the second outer endpoint B. The arc length of the first outer endpoint A and the second outer endpoint B between two adjacent blades 2 along the circumferential direction of the central disk 1 is S1. The arc length of the second outer endpoint B corresponding to one blade 2 and the second outer endpoint B corresponding to another blade 2 along the circumferential direction of the central disk 1 is S2, where 0.45 < S1 / S2 ≤ 0.57.

[0066] If the ratio of S1 to S2 is too small, such as less than or equal to 0.45, the opening at the outlet of the airflow channel 23 will be too small, increasing the airflow resistance and affecting the airflow volume. If the ratio of S1 to S2 is too large, such as greater than 0.57, the opening at the outlet of the airflow channel 23 will be too large, affecting the airflow velocity. By limiting the ratio to 0.45 < S1 / S2 ≤ 0.57, it is beneficial to reduce S2 and avoid S2 being too small. This ensures the airflow resistance, airflow volume, and airflow velocity while suppressing airflow separation in the airflow channel 23, increasing the work capacity of the centrifugal impeller 100 at high speeds, making the static pressure capacity of the centrifugal impeller 100 higher, and improving the working efficiency of the centrifugal impeller 100.

[0067] It should be noted that the ratio of S1 to S2 can be any value greater than 0.45 and less than or equal to 0.57. For example, the ratio of S1 to S2 can be any value among 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, and 0.57.

[0068] In some embodiments, S1 = (360° / z) × π × (d1 / 2) / 180, where d1 represents the outer diameter of blade 2 and z represents the number of blades 2. This setting facilitates the determination of S2 based on the specific values ​​of d1 and z of the centrifugal impeller 100, avoiding S2 being too large or too small.

[0069] In some embodiments, such as Figures 5 to 8 As shown, the circle represented by the inner diameter of blade 2 is the inner circle 20. The extension line of the suction arc 211 near the central axis of the middle disk 1 intersects the inner circle 20 at the first intersection point C. The line connecting the first intersection point C and the projection point O of the central axis of the middle disk 1 on the preset plane is the first connecting line L1.

[0070] The circle shown by the outer diameter of blade 2 is the outer circle 10. The end of pressure arc 221 away from the central axis of the middle disk 1 intersects the outer circle 10 at the second intersection point D. The line connecting the second intersection point D and the projection point O is the second connecting line L2. The angle between the first connecting line L1 and the second connecting line L2 corresponding to any blade 2 is α. The inlet angle of suction surface 21 is a1, the inlet angle of pressure surface 22 is a2, the outlet angle of suction surface 21 is b1, the outlet angle of pressure surface 22 is b2, a1>a2, b1+1.5×α<b2<b1+3×α.

[0071] While limiting 0.45 < S1 / S2 ≤ 0.57 and a1 > a2, if b2 ≤ b1 + 1.5 × α, the extension direction of blade 2 will be too close to a straight line; if b2 ≥ b1 + 3 × α, blade 2 will bend too much and form vortices, which is not conducive to airflow and will also increase noise and wind resistance. By limiting b1 + 1.5 × α < b2 < b1 + 3 × α, the airflow is more smoothly flowing in the airflow channel 23, reducing the generation of vortices on the pressure surface 22, thereby improving the work capacity of the centrifugal impeller 100, making the static pressure capacity of the centrifugal impeller 100 higher, and improving the working efficiency of the centrifugal impeller 100.

[0072] It should be noted that b2 can be any value greater than b1 + 1.5 × α and less than b1 + 3 × α. For example, b2 can be any value from b1 + 1.6 × α, b1 + 1.7 × α, b1 + 1.8 × α, b1 + 1.9 × α, b1 + 2.0 × α, b1 + 2.1 × α, b1 + 2.2 × α, b1 + 2.3 × α, b1 + 2.4 × α, b1 + 2.5 × α, b1 + 2.6 × α, b1 + 2.7 × α, b1 + 2.8 × α, and b1 + 2.9 × α. Preferably, b2 = b1 + 2.5 × α.

[0073] The blade 2 has two opposite sides along the radial direction of the central disk 1, namely the inner side 24 and the outer side 25. The inner side 24 is closer to the central axis of the central disk 1 than the outer side 25. One end of the inner side 24 along the circumference of the central disk 1 is smoothly connected to the suction surface 21 through an arc surface, and the other end is connected to the pressure surface 22 through an arc surface. One end of the outer side 25 along the circumference of the central disk 1 is smoothly connected to the suction surface 21 through an arc surface, and the other end is connected to the pressure surface 22 through an arc surface.

[0074] The inner surface 24 intersects the middle plate 1 at the inner intersection line 241. The endpoints of the inner intersection line 241 along the circumference of the middle plate 1 are E1 and F1, respectively. E1 is closer to the suction arc 211, and F1 is closer to the pressure arc 221. E1 and F1 are located on a circle centered at the projection point O, which is the inner circle 20. The projection of the outer surface 25 onto the preset plane is the outer projection 251. The endpoints of the outer projection 251 along the circumference of the middle plate 1 are E2 and F2, respectively. E2 is closer to the suction arc 211, and F2 is closer to the pressure arc 221. E2 and F2 are located on a circle centered at the projection point O, which is the outer circle 10.

[0075] In some embodiments, such as Figure 6 As shown, the straight line tangent to the pressure arc 221 and passing through the projection point O is the preset tangent line L. The angle between the preset tangent line L corresponding to any blade 2 and the second connecting line L2 is β; 0.6≤β / α≤0.8. If β / α<0.6, the extension direction of blade 2 will be too close to a straight line; if β / α>0.8, blade 2 will bend and form vortices, which is not conducive to air outlet and will also increase noise and wind resistance. By limiting 0.6≤β / α≤0.8, it is beneficial for the airflow to flow more smoothly in the airflow channel 23, reducing the generation of vortices on the pressure surface 22, thereby improving the work capacity of the centrifugal impeller 100, making the static pressure capacity of the centrifugal impeller 100 higher, and improving the working efficiency of the centrifugal fan.

[0076] It should be noted that β / α can be any value greater than or equal to 0.6 and less than or equal to 0.8, such as any value among 0.6, 0.65, 0.7, 0.75, and 0.8. Preferably, β / α = 0.7.

[0077] In some embodiments, such as Figure 6 and Figure 7 As shown, 63°≤a1<90°, 126°≤b1<130°; 60°≤a2<90°, 126°<b2<150°. This setting facilitates the entry of airflow into the airflow channel 23 and the exit of airflow from the airflow channel 23, thereby improving the work capacity and working efficiency of the centrifugal impeller 100.

[0078] a1 can be any angle greater than or equal to 63° and less than 90°, b1 can be any angle greater than or equal to 126° and less than 130°, a2 can be any angle greater than or equal to 60° and less than 90°, and b1 can be any angle equal to 126° and less than 150°. For example, a1 = 63°, b1 = 127°; a2 = 60°, b2 = 138°.

[0079] In some embodiments, such as Figure 5 As shown, the outer diameter of blade 2 is d1, and the inner diameter of blade 2 is d2. 0.78≤d2 / d1≤0.9. This setting ensures that the length of the airflow channel 23 meets the requirements, thereby improving the work capacity of the centrifugal impeller 100, increasing the static pressure capacity of the centrifugal impeller 100, and improving the working efficiency of the centrifugal impeller 100.

[0080] If the ratio of d2 to d1 is too large, the centrifugal fan's resistance performance will be poor, and blade 2 will not provide sufficient acceleration, easily leading to low static pressure after the airflow passes through blade 2, resulting in stalling. If the ratio of d2 to d1 is too small, the airflow channel 23 will be too long, increasing flow losses. The airflow will undergo a longer acceleration process, easily causing the aerodynamic performance of the centrifugal impeller 100 to deteriorate. The ratio of d2 to d1 can be any value greater than or equal to 0.78 and less than 1, such as any value among 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, and 0.9. Preferably, d2 / d1 = 0.8.

[0081] In some embodiments, such as Figure 2 As shown, the central disk 1 and the blades 2 are integrally molded injection-molded structures, which simplifies the machining of the centrifugal impeller 100 and reduces machining costs. In some other embodiments, the central disk 1 and the blades 2 can also be integrally die-cast structures.

[0082] In some embodiments, such as Figure 2 As shown, from one end of the blade 2 connected to the central disk 1 to the other end of the blade 2, the inner surface 24 gradually moves away from the central axis of the central disk 1 radially. The top surface 26 of the blade 2 at the end away from the central disk 1 smoothly connects to the inner surface 24 through an arc surface. Furthermore, from one end of the blade 2 connected to the central disk 1 to the other end of the blade 2, the top surface 26 of the blade 2 gradually moves away from the central axis of the central disk 1 radially. This arrangement facilitates airflow into the airflow channel 23, improves the work capacity of the centrifugal impeller 100, increases the static pressure capacity of the centrifugal impeller 100, and improves the working efficiency of the centrifugal impeller 100.

[0083] In some embodiments, such as Figure 1As shown, the blade located on one side of the central disk 1 is the first blade 2a, and the blade located on the other side of the central disk 1 is the second blade 2b. Multiple first blades 2a and multiple second blades 2b are arranged in a one-to-one correspondence, and the first blades 2a and the corresponding second blades 2b are arranged facing each other along the axial direction of the central disk 1.

[0084] As an alternative, the first blade 2a and the corresponding second blade 2b can be staggered along the circumference of the central disk 1 to increase the maximum static pressure of the centrifugal impeller 100; or some of the first blades 2a and the corresponding second blades 2b can be staggered along the circumference of the central disk 1, while another part of the first blades 2a and the corresponding second blades 2b can be arranged facing each other along the axial direction of the central disk 1.

[0085] In some embodiments, such as Figure 1 and Figure 2 As shown, the blade 2 with a maximum height of h2 and the motor 4 are located on the same side of the central plate 1. Specifically, for ease of description, the blade 2 with a maximum height of h1 is referred to as the first blade 2a, and the blade 2 with a maximum height of h2 is referred to as the second blade 2b. The second blade 2b and the motor 4 are located on the same side of the central plate 1.

[0086] Since the installation of motor 4 reduces the airflow space where the second blade 2b is located, placing motor 4 and the second blade 2b (which is relatively lower in height among the first blade 2a and the second blade 2b) on the same side of the middle plate 1 can make the air intake volume on the side where the second blade 2b is located match the height of the second blade 2b.

[0087] In some embodiments, such as Figure 1 , Figure 2 and Figure 9 As shown, the volute 3 has a first air inlet 351 and a second air inlet, which are located on opposite sides of the central plate 1, and the second air inlet and the motor 4 are located on the same side of the central plate 1. Specifically, the first air inlet 351 and the first blade 2a are located on the same side of the central plate 11, and the second air inlet and the second blade 2b are located on the same side of the central plate 11.

[0088] During the rotation of the centrifugal impeller 100, air enters from the first air inlet 351 and the second air inlet simultaneously. The airflow entering from the first air inlet 351 is sent to the air outlet of the volute 3 through the airflow channel 23 between two adjacent first blades 2a. The airflow entering from the second air inlet is sent to the air outlet of the volute 3 through the airflow channel 23 between two adjacent second blades 2b. This achieves double-sided air intake for the centrifugal fan, increases the air intake volume of the centrifugal impeller 100, and meets the requirements for strong blowing, especially suitable for gas water heaters with multiple speed settings.

[0089] Since the maximum height h1 of the first blade 2a is less than the maximum height h2 of the second blade 2b, the air intake volume of the first air inlet 351 is required to be less than the air intake volume of the second air inlet. Therefore, in some embodiments, the cross-sectional area of ​​the second air inlet is less than the cross-sectional area of ​​the first air inlet 351 to meet the air intake requirements of the first air inlet 351 and the second air inlet.

[0090] In some embodiments, such as Figure 1 As shown, the volute 3 includes a motor mounting part 32 and a shell body 31. The shell body 31 is provided with a through hole communicating with its inner cavity. One end of the motor 4 passes through the motor mounting part 32. One end of the motor mounting part 32 is located in the through hole. The motor mounting part 32 is connected to the shell body 31 by a plurality of connecting ribs 33 arranged at intervals along its circumference, so that the through hole is divided into a plurality of sub-air inlets 34. The second air inlet includes a plurality of the sub-air inlets 34.

[0091] The motor 4 is supported by the motor mounting part 32, and air is introduced into the side where the second blade 2b is located through multiple sub-air inlets 34.

[0092] For example, the inner diameter of the through hole is equal to the inner diameter of the first air inlet 351, such that the sum of the cross-sectional areas of the multiple sub-air inlets 34 is less than the cross-sectional area of ​​the first air inlet 351.

[0093] It should be noted that, without the need to support the motor 4 through the motor mounting part 32, the inner diameter of the first air inlet 351 can be larger than the inner diameter of the second air inlet to meet the air intake requirements.

[0094] In some embodiments, such as Figure 1 and Figure 9 As shown, the volute 3 also includes an air guide shroud 35, which and the first blade 2a are located on the same side of the central disk 1. The air guide shroud 35 is connected to the shell body 31, and the first air inlet 351 is provided on the air guide shroud 35.

[0095] In other embodiments, the volute 3 may have only one air inlet, with the air inlet and motor 4 located on opposite sides of the central plate 1. The central plate 1 has multiple air guide holes arranged at intervals along its circumference. Specifically, the motor 4 and the second blade 2b are located on the same side of the central plate 1, and the air inlet and the first blade 2a are located on the same side of the central plate 1. During the rotation of the centrifugal impeller 100, air enters through the air inlet. Most of the airflow entering through the air inlet is sent to the air outlet of the volute 3 through the airflow channel 23 between two adjacent first blades 2a. Another part of the airflow flows through the guide holes to the side of the central plate 1 away from the air inlet, and is sent to the air outlet of the volute 3 through the airflow channel 23 between two adjacent second blades 2b. Since the installation of motor 4 increases the airflow resistance on the side where motor 4 is located, the air inlet and the taller first blade 2a are placed on the same side of the middle plate 1. This allows most of the airflow entering through the air inlet to be sent to the air outlet of the volute 3 through the airflow channel 23 between two adjacent first blades 2a, and a small amount of airflow to be sent to the air outlet of the volute 3 through the guide hole and then through the airflow channel 23 between two adjacent second blades 2b. This reduces the noise during the operation of the centrifugal impeller 100.

[0096] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0097] The specific embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A centrifugal impeller, characterized in that The middle disc (1) is provided with a plurality of blades (2) arranged along the circumferential direction of the middle disc (1) on both axial sides of the middle disc (1), the thickness of the blade (2) gradually increases from inside to outside along the radial direction of the middle disc (1), the adjacent two blades (2) on the same side of the middle disc (1) form an airflow channel (23), the width of the airflow channel (23) gradually increases and then gradually decreases from inside to outside along the radial direction of the middle disc (1), and the arc length of the airflow channel (23) along the circumferential direction of the middle disc (1) is the width of the airflow channel (23). The maximum height of the blade (2) on both sides of the middle disc (1) is different.

2. The centrifugal impeller of claim 1, wherein The blade (2) comprises a pressure surface (22) and a suction surface (21) oppositely arranged along the circumferential direction of the middle disc (1), the projection of the pressure surface (22) in a preset plane comprises a pressure circular arc (221), the projection of the suction surface (21) in a preset plane comprises a suction circular arc (211), and the preset plane is perpendicular to the axial direction of the middle disc (1). The end point of the pressure circular arc (221) at one end away from the central axis of the middle disc (1) is a first outer end point (A), and the end point of the suction circular arc (211) at one end away from the central axis of the middle disc (1) is a second outer end point (B). The arc length of the first outer end point (A) and the second outer end point (B) between the adjacent two blades (2) along the circumferential direction of the middle disc (1) is S1, and the arc length of the corresponding second outer end point (B) of one of the adjacent blades (2) and the corresponding second outer end point (B) of the other blade (2) along the circumferential direction of the middle disc (1) is S2, and 0.45 3. The centrifugal impeller of claim 2, wherein The circle represented by the inner diameter of the blade (2) is an inner circle (20), the extension line of the suction circular arc (211) at one end close to the central axis of the middle disc (1) intersects with the inner circle (20) at a first intersection point (C), and the connecting line of the first intersection point (C) and the projection point (O) of the central axis of the middle disc (1) on the preset plane is a first connecting line (L1). The circle represented by the outer diameter of the blade (2) is an outer circle (10), the pressure circular arc (221) at one end away from the central axis of the middle disc (1) intersects with the outer circle (10) at a second intersection point (D), and the connecting line of the second intersection point (D) and the projection point (O) is a second connecting line (L2); the included angle of the first connecting line (L1) and the second connecting line (L2) corresponding to any blade (2) is α; The inlet angle of the suction surface (21) is a1, the inlet angle of the pressure surface (22) is a2, the outlet angle of the suction surface (21) is b1, and the outlet angle of the pressure surface (22) is b2; a1>a2, b1+1.5×α 4. The centrifugal impeller of claim 3, wherein The tangent line of the projection point (O) and the pressure circular arc (221) is a preset tangent line (L), and the included angle of the preset tangent line (L) and the second connecting line (L2) corresponding to any blade (2) is β. 0.6≤β / α≤0.8。 5. The centrifugal impeller according to any one of claims 1 to 4, characterized in that The blade located on one side of the middle disc (1) is a first blade (2a), and the blade located on the other side of the middle disc (1) is a second blade (2b), and the first blades (2a) and the second blades (2b) are arranged in one-to-one correspondence. At least part of the first blades (2a) and the corresponding second blades (2b) are arranged in a circumferential direction of the middle disc (1); and / or, at least part of the first blades (2a) and the corresponding second blades (2b) are arranged in an axial direction of the middle disc (1).

6. The centrifugal impeller according to any one of claims 1 to 4, characterized in that The maximum height of the blade (2) located on one side of the middle disc (1) in the axial direction is h1, and the maximum height of the blade (2) located on the other side of the middle disc (1) in the axial direction is h2, and 1 7. A centrifugal fan, characterized by The centrifugal fan (100) according to any one of claims 1 to 6, wherein the centrifugal fan (100) is rotatably installed in the volute (3), the maximum height of the blade (2) located on one side of the middle disc (1) in the axial direction is h1, and the maximum height of the blade (2) located on the other side of the middle disc (1) in the axial direction is h2, and 1 8. The centrifugal fan of claim 7, wherein The volute (3) has an air inlet, and the air inlet and the motor (4) are located on opposite sides of the middle disc (1), and the middle disc (1) is provided with a plurality of air guide holes arranged in a circumferential direction of the middle disc (1); Or, the volute (3) has a first air inlet (351) and a second air inlet, the first air inlet (351) and the second air inlet are located on opposite sides of the middle disc (1), and the second air inlet and the motor (4) are located on the same side of the middle disc (1).

9. The centrifugal fan of claim 8, wherein The cross-sectional area of the second air inlet is smaller than the cross-sectional area of the first air inlet (351).

10. An apparatus using a centrifugal fan, characterized by, The centrifugal fan according to any one of claims 7 to 9. The centrifugal fan according to any one of claims 7 to 9.

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