Centrifugal fan and air treatment device

Abstract

The utility model discloses a centrifugal fan and an air treatment device, and belongs to the technical field of air treatment. The centrifugal fan comprises a volute provided with an air suction part allowing air to flow in; the air guide ring is connected to the air suction part; the centrifugal fan is arranged in the volute, the centrifugal fan and the air guide ring are coaxially arranged, and the air inlet side of the centrifugal fan faces the air guide ring; wherein the centrifugal fan comprises a plurality of blades which are arranged along the circumference; and the outer diameter D0 of the centrifugal fan at the blades and the inner diameter D1 of the air guide ring meet the condition that D1 is equal to (0.83-0.91) D0. The centrifugal fan and the air treatment device can improve unstable air inlet noise.

Description

Technical Field

[0001] The present application relates to the technical field of air treatment, and in particular to a centrifugal fan and an air treatment device. Background Art

[0002] Air handling devices, such as air conditioners, fresh air fans, and total heat exchangers, are used to process the air. Fans are commonly used inside them to drive the air flow.

[0003] Centrifugal fans are used in some air handling devices. These fans often have unstable intake noise on the intake side. It is measured that the intake noise will cause the overall noise OA to increase by 0.3 to 05dB (A). Although the increase is relatively small, it causes trouble to the user's hearing experience when using it. Utility Model Content

[0004] The present application provides a centrifugal fan and an air treatment device, which can improve unstable air intake noise.

[0005] In one aspect of the present application, a centrifugal fan comprises: a volute having an air suction portion for air to flow in; an air guide ring connected to the air suction portion; a centrifugal fan disposed in the volute, the centrifugal fan being coaxially arranged with the air guide ring and the air inlet side of the centrifugal fan facing the air guide ring; wherein the centrifugal fan comprises a plurality of blades arranged along a circumference; the outer diameter D0 of the centrifugal fan at the blades and the inner diameter D1 of the air guide ring satisfy: D1 = (0.83 to 0.91) D0.

[0006] In some embodiments, the axial spacing X2 between the centrifugal fan and the air guide ring and the axial width H1 of the centrifugal fan satisfy: Q is the volume flow rate of the centrifugal fan in the working range, is the pressure coefficient.

[0007] In some embodiments, the axial length of the centrifugal fan ω is the angular velocity of the centrifugal fan, n∈[0.4, 1.2].

[0008] In some embodiments, the inner diameter D2 of the air suction portion and the inner diameter D1 of the air guide ring satisfy: D2 ≥ (1.06-1.29) D1.

[0009] In some embodiments, the inner diameter D2 of the air suction portion and the inner diameter D1 of the air guide ring satisfy: D2=D1+2D, where D is 5, 6, 8, 10 or 12.

[0010] In some embodiments, the axial distance X1 from the air inlet end of the centrifugal fan to the outer side surface of the air suction portion is equal to X2+D, where D is 5, 6, 8, 10 or 12.

[0011] In some embodiments, the air guide ring includes: a fixed portion, which is in contact with the volute; a guide portion, which is connected to the inner circle of the fixed portion, and the guide portion is in an arc-shaped ring, and the radius of the guide portion R1 = (16-30) mm.

[0012] In some embodiments, the centrifugal fan includes a plurality of blades arranged along a circumference, and two adjacent blades are defined as a first blade and a second blade; a fillet R2 on the first blade near the air inlet end is not equal to a fillet R3 on the second blade near the air inlet end.

[0013] In some embodiments, the centrifugal fan includes a plurality of blades arranged along a circumference, and when projected onto a plane perpendicular to the axis of the centrifugal fan, the inner circle of the air guide ring intersects with the blades.

[0014] In another aspect of the present application, an air treatment device includes the centrifugal fan mentioned above. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 shows a schematic diagram of an air conditioner according to some embodiments;

[0016] Figure 2 The velocity cloud diagram of the air inlet grille of the air conditioner in the prior art when the distance between the air inlet grille and the centrifugal fan is 70 mm is shown;

[0017] Figure 3 The velocity cloud diagram of the air inlet grille of the air conditioner in the prior art when the distance between the air inlet grille and the centrifugal fan is 30 mm is shown;

[0018] Figure 4 shows a perspective view of a centrifugal fan according to some embodiments;

[0019] Figure 5 A perspective view of a volute in a centrifugal fan according to some embodiments is shown;

[0020] Figure 6 A perspective view of a volute body in a centrifugal fan according to some embodiments is shown;

[0021] Figure 7 A perspective view of an air guide ring in a centrifugal fan according to some embodiments is shown;

[0022] Figure 8 and Fig. 9 A perspective view of an impeller in a centrifugal fan according to some embodiments is shown;

[0023] Fig.10 shows a cross-sectional view of a centrifugal fan according to some embodiments;

[0024] Fig.11 shows a velocity cloud diagram of an air conditioner on the air inlet side of a centrifugal fan according to some embodiments;

[0025] Fig.12 shows a side view of a blade in a centrifugal fan according to some embodiments;

[0026] Fig.13 A pressure contour diagram of an impeller in a centrifugal fan according to some embodiments is shown.

[0027] In the above figures, 10, shell; 11, air inlet; 12, air outlet; 13, air inlet grille; 20, heat exchanger; 100, centrifugal fan; 110, volute; 111, volute body; 112, cover plate; 113, air suction part; 114, air exhaust part; 115, convex part; 120, centrifugal fan; 121, impeller; 1211, hub; 1212, blades; 1213, first circle; 1214, second circle; 122, motor; 130, air guide ring; 131, fixing part; 1311, buckle; 132, guide part. DETAILED DESCRIPTION

[0028] In order to make the purpose and implementation method of the present application clearer, the exemplary implementation method of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0029] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0030] The terms "first", "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0031] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] The air treatment device of the present application may be an air conditioner, an air purifier, a fresh air blower, a total heat exchanger, etc. A fan is required in the air treatment device to drive the flow of air.

[0033] The following is a detailed introduction taking the air conditioner in the air handling device as an example:

[0034] The air conditioner performs the refrigeration cycle of the air conditioner by using a compressor, a condenser, an expansion valve and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion and evaporation, and supplies refrigerant to the air that has been conditioned and heat exchanged.

[0035] The compressor compresses the refrigerant gas in a low temperature and low pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0036] The expansion valve expands the high-temperature and high-pressure liquid refrigerant condensed in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigeration effect by utilizing the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. In the entire cycle, the air conditioner can adjust the temperature of the indoor space.

[0037] The outdoor unit of the air conditioner refers to a portion of a refrigeration cycle including a compressor and an outdoor heat exchanger, the indoor unit of the air conditioner includes an indoor heat exchanger, and an expansion valve may be provided in the indoor unit or the outdoor unit.

[0038] The indoor heat exchanger and the outdoor heat exchanger function as a condenser or an evaporator. When the indoor heat exchanger functions as a condenser, the air conditioner functions as a heater in a heating mode, and when the indoor heat exchanger functions as an evaporator, the air conditioner functions as a cooler in a cooling mode.

[0039] The air conditioner according to the embodiment of the present application may be an all-in-one unit in which an indoor unit and an outdoor unit are integrated in one housing, or may be a split unit in which the indoor unit and the outdoor unit are independently and separately installed.

[0040] The following is an introduction using the indoor unit in a split unit and the indoor unit as a floor-standing cabinet as an example:

[0041] Reference Figure 1 According to an embodiment of the present application, the air treatment device includes a housing 10 in which a plurality of components constituting a refrigeration cycle are installed.

[0042] The housing 10 is in a rectangular box shape, and an air inlet 11 is provided on the side of the lower part of the housing 10, and the air inlet 11 is used to allow indoor air to enter the housing 10. An air outlet 12 is provided on the front side of the upper part of the housing 10, and the air outlet 12 is used to circulate the treated indoor air into the indoor space.

[0043] An air inlet grille may be provided at the air inlet 11 to filter the indoor air entering the housing 10 to prevent dust and impurities from entering the housing 10 .

[0044] The air handling device may include a fan, which drives the flow of air so that the air in the indoor space enters the housing 10 from the air inlet 11 and is blown out from the air outlet 12 .

[0045] The fan may be a centrifugal fan 100, an air inlet end of the centrifugal fan 100 is arranged corresponding to the air inlet 11, and an air outlet end of the centrifugal fan 100 faces upward.

[0046] The air treatment device may include a heat exchanger 20, which is disposed on the air outlet side of the centrifugal fan 100, that is, above the centrifugal fan 100, and the centrifugal fan 100 is located on the air movement path from the air inlet 11 to the air outlet 12. The heat exchanger 20 is used to absorb heat from the air blown out by the centrifugal fan 100 or transfer heat to the air.

[0047] The water receiving pan may be provided below the heat exchanger 20 to collect moisture condensed in the heat exchanger 20. The water receiving pan may be connected to a drain hose connected to the outside of the housing 10, and may discharge the condensed moisture to the outside of the housing 10.

[0048] Reference Figure 1 , the arrows in the figure indicate the direction of air flow. When the air handling device is working, the centrifugal fan 100 runs, so that the air in the indoor space enters from the air inlet grille, then passes through the centrifugal fan 100, flows to the heat exchanger 20, exchanges heat with the heat exchanger 20, and is discharged to the indoor space through the air outlet 12.

[0049] When the centrifugal fan 100 is working, an unstable air intake noise of "pu pu pu" will be generated on the air inlet side. Figure 2 and Figure 3 , Figure 2The velocity cloud diagram of the centrifugal fan in the air handling device when the air inlet side is 70 mm away from the air inlet grille is shown. Figure 3 The velocity cloud diagram of the centrifugal fan in the air handling device when the air inlet side is 30 mm away from the air inlet grille is shown. Figure 2 and Figure 3 It is found that no matter how far the air inlet grille 13 is from the centrifugal fan 100 , the unevenness of the air intake state cannot be eliminated, that is, the purpose of eliminating the air intake noise cannot be achieved by changing the distance from the centrifugal fan 100 to the air inlet grille 13 .

[0050] Therefore, the present application improves the matching relationship of the components in the centrifugal fan 100 and achieves the purpose of eliminating the intake noise.

[0051] Reference Figures 4 to 6 According to the embodiment of the present application, the centrifugal fan 100 includes a volute 110. The volute 110 includes a volute body 111 and a cover plate 112. The volute body 111 is a thin shell, and one side of the axial direction of the volute body 111 is open to facilitate the installation of the centrifugal fan 120 from the open end. The cover plate 112 is provided on the open side of the volute body 111 to close the volute body 111.

[0052] An air suction portion 113 is provided at one end of the volute body 111 opposite to the cover plate 112. The air suction portion 113 may be circular.

[0053] The top of the volute 110 is provided with an exhaust portion 114 for air to flow out. The air flows in from the air suction portion 113 of the volute 110 and then flows out from the exhaust portion 114 at the top.

[0054] Combined with reference Figure 7 The centrifugal fan 100 may include an air guide ring 130 , which is connected to the air suction portion 113 . The air guide ring 113 has a guiding function for guiding the air flow to the centrifugal fan 120 .

[0055] The air guide ring 130 includes a fixing portion 131 . The fixing portion 131 is in the shape of an annular sheet and is used to be connected to the volute 110 .

[0056] A buckle 1311 is provided on the inner side of the fixing portion 131 (the side facing the volute 110), a mounting hole is provided on the volute 110, a convex portion 115 is provided on the inner side wall of the volute 110, and the buckle 1311 extends from the mounting hole into the inner side of the volute 110 to hook the convex portion 115, so as to realize the clamping connection between the air guide ring 130 and the volute 110. In the assembled state, the fixing portion 131 abuts against the side wall of the volute 110.

[0057] There are multiple clamping structures between the air guide ring 130 and the volute 110 evenly distributed on the circumference to ensure the connection stability and reliability of the air guide ring 130 on the volute 110.

[0058] The air guide ring 130 includes a guide portion 132 for guiding the flow of air. The guide portion 132 is in an arc-shaped ring shape and is connected to the inner side of the air guide ring 130. The guide portion 132 is specifically formed by extending the inner circle of the fixing portion 131 into the volute 110.

[0059] Reference Figure 8 and Fig. 9 The centrifugal fan 100 includes a centrifugal fan 120 , which may be a single-side air intake centrifugal fan. The air intake end of the centrifugal fan 120 is connected to the volute 110 corresponding to the air guide ring 130 .

[0060] The centrifugal fan 120 includes an impeller 121 having a first circle 1213 , and a plurality of blades 1212 are arranged on the first circle 1213 along a circumferential direction. The outer periphery of one end of the blade 1212 away from the first circle 1213 is connected to the second circle 1214 , thereby the blade 1212 is fixed by the first circle 1213 and the second circle 1214 .

[0061] The impeller 121 includes a hub 1211 , which is in a cover shape, connected to the inner end of the first ring 1213 and located in a cylindrical space surrounded by a plurality of blades 1212 .

[0062] The first circle 1213 , the second circle 1214 , the blades 1212 , and the hub 1211 of the centrifugal fan 120 may be integrally formed.

[0063] Combined with reference Fig.10 The centrifugal fan 120 includes a motor 122, which is connected to the impeller 121 and serves as a power source for the impeller 121 to rotate. The motor 122 is located in the hub 1211, and the output shaft of the motor 122 is connected to the hub 1211. When the motor 122 is working, the output shaft of the motor 122 drives the impeller 121 to rotate.

[0064] The motor 122 is fastened to the cover plate 112 of the volute 110 by fasteners such as screws, so as to realize the connection of the centrifugal fan 120 in the volute 110 .

[0065] In the assembled state, the first circle 1213 of the impeller 121 is close to the cover plate 112 , and one end where the second circle 1214 of the impeller 121 is located forms the air inlet side of the centrifugal fan 120 .

[0066] The centrifugal fan described above is a centrifugal fan structure with single-side air intake. However, the present application is also applicable to a centrifugal fan structure with double-side air intake.

[0067] The difference between the double-sided air intake centrifugal fan structure and the above-mentioned structure is that a suction portion 113 is also provided on the cover plate 112 side of the volute 110, that is, a suction portion 113 is provided on each axial side of the volute 110, and each suction portion 113 is connected to an air guide ring 130; the centrifugal fan 120 is a double-sided air intake centrifugal fan, and the axis of the centrifugal fan 120 is coaxial with the axis of the air guide ring 130.

[0068] When the centrifugal fan 120 rotates, air flows in from both sides of the volute 110 , and then flows out from the exhaust portion 114 after being merged in the volute 110 .

[0069] In some embodiments, a portion of the blades 1212 can be seen from the air guide ring 130 into the volute 110. That is, when projected on a plane perpendicular to the axis of the centrifugal fan 120, the inner circle of the air guide ring 130 intersects with the blades 1212, so that the air flow can be completely flowed to the impeller 121 under the guidance of the air guide ring 130.

[0070] If the inner circle of the air guide ring 130 does not intersect with the hub 1211, in one case, the blades 1212 are completely outside the inner circle of the air guide ring 130 in projection. Although the air flow can flow to the impeller 121, the air volume will be relatively small. In another case, the blades 121 are completely inside the inner circle of the air guide ring 130 in projection, and part of the air flow may be dispersed outside the impeller 121, resulting in air flow impact. Therefore, in the present application, the inner circle of the air guide ring 130 is arranged to intersect with the blades 1212.

[0071] In some embodiments, reference Fig.10 The outer diameter of the centrifugal fan 120 is recorded as D0, which is specifically the outer diameter of the middle part of the axial direction of the centrifugal fan 120, that is, the outer diameter formed at the blade 1212; the inner diameter of the air guide ring 130 is recorded as D1.

[0072] The relationship between D1 and D0 satisfies: D1 ≥ 0.83D0. If the ratio D1 / D0 is too small, the air intake of the centrifugal fan will be reduced, thereby reducing the working efficiency of the air treatment device. Therefore, the setting of D1 ≥ 0.83D0 in this application can ensure the normal air intake of the centrifugal fan and the working efficiency of the air treatment device.

[0073] The relationship between D1 and D0 satisfies: D1≤0.91D0. If the ratio of D1 / D0 is too large, the outer ring airflow guided by the air guide ring 130 may flow outside D0, and then flow into the impeller 121 from the outer diameter of the blade 1212, which will cause airflow impact and increase the airflow noise. Therefore, the present application sets D1≤0.91D0 to reduce the intake noise.

[0074] In some embodiments, the axial width of the centrifugal fan 120 is denoted as H1. The relationship between the axial width H1 of the centrifugal fan 120 and the outer diameter D0 of the centrifugal fan 120 satisfies:

[0075]

[0076] Q represents the volume flow rate of the working range of the centrifugal fan 120 of the present application. When the outer diameter D0 of the centrifugal fan 120 is 300-400 mm, Q = 1000-2400 mm. 3 / h.

[0077] ω represents the angular velocity range of the centrifugal fan 120 of the present application, ω∈[41, 63]; n∈[0.4, 1.2].

[0078] Therefore, in the present application, after the outer diameter D0 of the centrifugal fan 120 is determined, the width range of the centrifugal fan 120 can be determined according to the relationship between H1 and D0.

[0079] Under this relationship between H1 and D0 , the centrifugal fan 120 can meet the speed and flow required for operation, thereby ensuring the operating performance of the centrifugal fan 120 .

[0080] In some embodiments, the axial spacing between the centrifugal fan 120 and the air guide ring 130 is recorded as X2, and the relationship between X2 and H1 satisfies:

[0081]

[0082] is the pressure coefficient, which can be calculated using the pressure coefficient formula.

[0083] After X2 is taken according to the above relationship, the air guide ring 130 is guaranteed to guide the air to the centrifugal fan 120, avoiding the problem of collision between the air guide ring 130 and the centrifugal fan 120 due to vibration and impact when the air guide ring 130 is too close to the centrifugal fan 120, and avoiding the problem of serious airflow leakage when the air guide ring 130 is too far from the centrifugal fan 120.

[0084] The inner diameter of the air suction portion 113 of the volute 110 is denoted as D2, and D2 and the inner diameter D1 of the air guide ring 130 satisfy the following relationship: D2 ≥ (1.06-1.29) D1.

[0085] The inner diameter D2 of the air suction portion 113 and the inner diameter D1 of the air guide ring satisfy: D2=D1+2D, where D is a constant and D is equal to any value among 5, 6, 8, 10, and 12.

[0086] An axial distance X1 from the air inlet end of the centrifugal fan 120 to the outer side surface of the air suction portion 113 of the volute 110 is equal to X2+D.

[0087] The radius R1 of the guide portion 132 of the air guide ring 130 is (16-30) mm.

[0088] Fig.11 It shows the flow state after the parameters of the centrifugal fan 100 are improved. According to the test, the flow rate of the centrifugal fan 100 of the present application is increased by 10-20m at the same speed compared with the centrifugal fan of the prior art. 3 / h, and eliminated the puffing intake noise.

[0089] In some embodiments, reference Fig.12 The two adjacent blades 1212 in the centrifugal fan 120 are respectively the first blade and the second blade. The rounded corner on the end surface of the first blade close to the air inlet end is marked as R2, and the rounded corner on the end surface of the second blade close to the air inlet end is marked as R3, and R2≠R3.

[0090] Reference Fig.13 After the top fillets of two adjacent blades are adjusted to different values, the impact of the air flow on the blade top is weakened, making the incoming air flow smoother and more uniform, and the airflow noise is reduced.

[0091] In the present application, setting D1≥0.83D0 can ensure the normal air intake volume of the centrifugal fan and the working efficiency of the air handling device; setting D1≤0.91D0 can reduce the air intake noise.

[0092] In this application, set The speed and flow rate required for work can be met, thereby ensuring the working performance of the centrifugal fan 120 .

[0093] In this application, set The air guide ring 130 is ensured to have an air guiding effect on the centrifugal fan 120 , thereby avoiding the problem of collision between the air guide ring 130 and the centrifugal fan 120 due to vibration and impact when the air guide ring 130 is too close to the centrifugal fan 120 , and also avoiding the problem of blade tip leakage when the air guide ring 130 is too far from the centrifugal fan 120 .

[0094] In the present application, after limiting the structural parameters of the centrifugal fan, the flow state of the intake air is improved, so that the flow rate of the centrifugal fan 100 of the present application is increased by 10 to 20 m / s compared with the centrifugal fan of the prior art at the same speed. 3 / h, and eliminated the puffing intake noise.

[0095] In the present application, after the top fillets of two adjacent blades have different values, the impact of the incoming air flow on the blade top is weakened, making the incoming air flow smoother and more uniform, and the airflow noise is reduced.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0097] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A centrifugal fan, characterized in that: include: A volute having an air suction portion for air to flow into; An air guide ring connected to the air suction part; A centrifugal fan is disposed in the volute, the centrifugal fan and the air guide ring are coaxially arranged and the air inlet side of the centrifugal fan faces the air guide ring; Wherein, the centrifugal fan comprises a plurality of blades arranged along a circumference; The outer diameter D0 of the centrifugal fan at the blade and the inner diameter D1 of the air guide ring satisfy the following condition: D1 = (0.83-0.91) D0.

2. The centrifugal fan according to claim 1, characterized in that: The axial spacing X2 between the centrifugal fan and the air guide ring and the axial width H1 of the centrifugal fan satisfy: Q is the volume flow rate of the centrifugal fan in the working range, is the pressure coefficient.

3. The centrifugal fan according to claim 1, characterized in that: The axial length of the centrifugal fan Q is the volume flow rate in the working range of the centrifugal fan, ω is the angular velocity of the centrifugal fan, n∈[0.4, 1.2].

4. The centrifugal fan according to claim 1, characterized in that: The inner diameter D2 of the air suction portion and the inner diameter D1 of the air guide ring satisfy: D2 ≥ (1.06-1.29) D1.

5. The centrifugal fan according to claim 1, characterized in that: The inner diameter D2 of the air suction portion and the inner diameter D1 of the air guide ring satisfy: D2=D1+2D, where D is 5, 6, 8, 10 or 12.

6. The centrifugal fan according to claim 1, characterized in that: An axial distance X1 from the air inlet end of the centrifugal fan to the outer side surface of the air suction portion is equal to X2+D, where D is 5, 6, 8, 10 or 12.

7. The centrifugal fan according to claim 1, characterized in that: The air guide ring comprises: A fixing portion abutting against the volute; The guide part is connected to the inner circle of the fixing part, and the guide part is in an arc-shaped circle, and the radius R1 of the guide part is (16-30) mm.

8. The centrifugal fan according to claim 1, characterized in that: The centrifugal fan includes a plurality of blades arranged along a circumference, and two adjacent blades are defined as a first blade and a second blade; a rounded corner on an end surface of the first blade close to an air inlet end is R2, and a rounded corner on an end surface of the second blade close to an air inlet end is R3, and R2 and R3 are not equal.

9. The centrifugal fan according to claim 1, characterized in that: The centrifugal fan includes a plurality of blades arranged along a circumference. When projected onto a plane perpendicular to the axis of the centrifugal fan, an inner circle of the air guide ring intersects with the blades.

10. An air treatment device, characterized in that: A centrifugal fan comprising any one of claims 1 to 9.

Images