A volute, a centrifugal fan and a kitchen appliance

Abstract

The present invention relates to the technical field of oil fume purification, and in particular to a volute, a centrifugal fan and a kitchen appliance. The volute provided by the present invention has a volute profile line including a first straight line segment, a volute tongue segment, a first curved line segment, a second curved line segment and a second straight line segment connected in sequence, the second curved line segment is a gradually expanding variable angle spiral line segment, and the gradually expanding variable angle spiral line has a continuous change trend of expansion degree from small at the front to large at the back. On the one hand, the overall volute height can be kept small by adjusting the upper and lower spaces, which can meet the installation space restriction requirements; on the other hand, the use of a small flow space in the small flow area at the upper end of the volute has little effect on the performance, and the large flow gas confluence area in the volute flow channel has a larger internal flow space, which can effectively reduce the average flow velocity in the area, reduce flow losses, and enhance the drainage and pressure diffusion effect of the volute.

Description

Technical Field

[0001] The present invention relates to the technical field of oil fume purification, and in particular to a volute, a centrifugal fan and a kitchen appliance. Background Art

[0002] Cooking in the kitchen usually produces a lot of fumes, which directly affects people's living environment and health. As an important tool to improve the indoor environment of the kitchen, the range hood can purify the indoor air by absorbing and exhausting the cooking fumes in the kitchen. The fan is the core power component of the range hood. Its aerodynamic performance directly determines the overall working performance of the range hood. Multi-blade centrifugal fans are widely used in range hoods because of their high pressure coefficient, large flow coefficient and low working noise.

[0003] One of the structural characteristics of traditional multi-blade centrifugal fans is that the width and diameter of the impeller are relatively large, so the axial structural dimensions of the fan are generally large, and the fan cannot usually be placed downward. Usually, the only way to improve the oil fume extraction effect is to extend the inlet of the range hood downward. However, there is still a problem that the centrifugal fan inlet is far away from the smoke emission position of the lower pot, which affects the oil fume extraction effect of the range hood. In response to the above problems, most of the solutions currently adopted are: reduce the axial dimensions of the multi-blade centrifugal fan, and then place the fan down close to the smoke emission position of the pot. However, according to the centrifugal fan design theory, if the axial dimensions of the multi-blade centrifugal fan are to be reduced while still maintaining the fan's work capacity unchanged, the impeller diameter needs to be increased, and then the volute profile will increase accordingly. At the same time, the use scenario of the ultra-thin close-suction range hood determines that the height of its main housing cannot be too large, so there are strong restrictions on the structural dimensions of the thin centrifugal fan volute, especially the height dimension.

[0004] Therefore, a centrifugal fan is urgently needed to solve the above problems. Summary of the invention

[0005] The first object of the present invention is to provide a volute that can improve the aerodynamic and noise performance of the fan while limiting the thickness and height space dimensions.

[0006] A second object of the present invention is to provide a centrifugal fan which, by applying the above-mentioned volute, can improve the aerodynamic and noise performance of the fan while limiting the thickness and height space dimensions.

[0007] The third object of the present invention is to provide a kitchen appliance which can improve the oil fume absorption effect by applying the above-mentioned centrifugal fan.

[0008] In order to achieve the above objectives, the following technical solutions are provided:

[0009] In a first aspect, a volute is provided, wherein a volute profile of the volute comprises a first straight line segment, a volute tongue segment, a first curved line segment, a second curved line segment, and a second straight line segment connected in sequence, wherein the second curved line segment is a spiral line segment, and an XY coordinate system is set with an impeller rotation axis O1 as the origin, and the second curved line segment satisfies the following formula:

[0010]

[0011] Wherein, D2 is the outer diameter of the impeller outlet, is the rotation angle between the line O1G connecting any point G on the second curve segment and the impeller rotation axis O1 and the negative direction of the X axis, is the airflow angle of the helix, k is the characteristic angle constant, 3°≤k≤5°, The circumferential rotation angle A continuously monotonically increasing function of change, And its derivative

[0012] As an optional solution for the volute, the volute tongue profile segment is an arc segment, and the angle between the line O1O2 connecting the center O2 of the volute tongue profile and the impeller rotation axis O1 and the X-axis is β1, and the range of β1 is 65°-85°.

[0013] As an optional solution for the volute, the angle formed by the first straight line segment and the X-axis is α1, and the angle formed by the second straight line segment and the X-axis is α2, wherein 50°≤α2≤70°, and 10°≤α2-α1≤20°.

[0014] As an optional solution for the volute, the outer diameter D2 of the impeller outlet ranges from 250 mm to 350 mm.

[0015] As an optional solution of the volute, the radius R1 of the volute tongue-shaped line segment ranges from 8 mm to 12 mm.

[0016] As an optional scheme for the volute, the first curved segment is an arc segment, the first curved segment is tangent to the volute tongue-shaped line segment at point C, the first curved segment is tangent to the second curved segment at point D, the distance between point C and the outer diameter of the impeller outlet is the volute tongue distance t, and the range of the volute tongue distance t is 10mm-15mm.

[0017] As an optional solution for the volute, the length of a line connecting a starting point of the first straight line segment and an end point of the second straight line segment is L1, wherein 150 mm ≤ L1 ≤ 200 mm.

[0018] As an optional solution for the volute, the maximum height of the volute is H1, wherein 350 mm ≤ H1 ≤ 450 mm.

[0019] In a second aspect, a centrifugal fan is provided, comprising an impeller, a motor and a volute as described above, wherein the impeller and the motor are both disposed in the volute.

[0020] In a third aspect, a kitchen appliance is provided, comprising the centrifugal fan as described above.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The volute provided by the present invention has a volute profile line comprising a first straight line segment, a volute tongue segment, a first curved segment, a second curved segment and a second straight line segment connected in sequence, the second curved segment is a gradually expanding variable angle spiral segment, and the gradually expanding variable angle spiral line has a continuous change trend of expansion degree from small at the front to large at the back, on the one hand, the overall volute height can be kept small by allocating the upper and lower spaces, and the installation space limitation requirements can be met; on the other hand, the use of a small flow space in the small flow area at the upper end of the volute has little effect on the performance, and the large flow gas confluence area in the volute flow channel has a larger internal flow space, which can effectively reduce the average flow velocity in the area, reduce flow losses, and enhance the drainage and pressure diffusion effect of the volute.

[0023] The centrifugal fan provided by the present invention, by applying the above-mentioned volute, can improve the aerodynamic and noise performance of the fan when the thickness and height space dimensions are limited.

[0024] The kitchen appliance provided by the present invention can improve the oil fume absorption effect by applying the centrifugal fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0026] Figure 1 A schematic structural diagram of a centrifugal fan provided in an embodiment of the present invention;

[0027] Figure 2 An exploded schematic diagram of a centrifugal fan provided by an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the structure of a volute provided in an embodiment of the present invention;

[0029] Figure 4 A schematic diagram of the structure of the volute profile provided in an embodiment of the present invention;

[0030] Figure 5 for Figure 4 The enlarged view of P in the middle;

[0031] Figure 6 An exploded schematic diagram of a volute provided in an embodiment of the present invention;

[0032] Figure 7 A schematic diagram of the structure of a volute shroud and an impeller provided in an embodiment of the present invention;

[0033] Figure 8 A schematic structural diagram of a volute provided with a noise reduction through hole according to an embodiment of the present invention.

[0034] Reference numerals:

[0035] 100-main air inlet; 200-air outlet;

[0036] 1. Volute; 11. Volute front plate; 12. Volute rear plate; 121. Motor seat; 13. Volute enclosure; 14. Outlet flange; 15. Noise reduction through hole; 16. Reinforcement ribs;

[0037] 2. Impeller;

[0038] 3. Motor;

[0039] 4. Air guide ring. DETAILED DESCRIPTION

[0040] In order to make the technical problem solved by the present invention, the technical solution adopted and the technical effect achieved more clearly, the technical solution of the present invention is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0041] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. In addition, the terms "first" and "second" are used only to distinguish in description and have no special meaning.

[0043] In order to facilitate understanding of the technical solution of the present invention, the width-to-diameter ratio of the impeller 2 refers to the ratio of the axial height of the centrifugal impeller 2 to the outer diameter of the impeller 2. The flow channel refers to the passage through which the fluid medium flows in the motion space. The axial direction is usually for cylindrical objects, that is, the direction of the central axis of rotation of the cylinder, that is, the common direction with the central axis. The radial direction refers to the straight line direction along the diameter or radius, or the straight line direction perpendicular to the axis, and the "radial" is perpendicular to the "axial". The circumferential direction refers to the "circumferential direction", which together with the "axial" and "radial" constitutes the three orthogonal directions of the cylindrical coordinates. An increasing function refers to a function in the domain of the independent variable. If the dependent variable increases with the increase of the independent variable, this function is called an increasing function.

[0044] Embodiment 1

[0045] This embodiment provides a kitchen appliance, including a centrifugal fan and a fume hood, wherein the centrifugal fan is arranged on the fume hood, and when the kitchen appliance is turned on, the centrifugal fan works to form a negative pressure in the fume hood, thereby sucking external oil smoke into the fume hood. Optionally, the kitchen appliance may only have a range hood with an oil fume suction function, or may be an integrated stove with functions of a gas stove and a range hood, which is not limited here.

[0046] Embodiment 2

[0047] This embodiment provides a centrifugal fan for the kitchen appliance of the first embodiment. Figure 1-Figure 2 As shown, the centrifugal fan includes a volute 1, an impeller 2 and a motor 3. The impeller 2 and the motor 3 are arranged in the volute 1. The motor 3 is used to drive the impeller 2 to rotate in the volute 1, so that negative pressure is generated in the smoke hood through the rotation of the impeller 2 to achieve the function of absorbing oil smoke. Among them, the motor 3 drives the impeller 2 to rotate, which is a prior art and is not described in detail here.

[0048] like Figure 3As shown, the volute 1 includes a volute front plate 11, a volute rear plate 12 and a volute enclosure 13. The outer edge shapes of the volute front plate 11 and the outer edge shapes of the volute rear plate 12 are both adapted to the outer edge shapes of the volute enclosure 13. The volute front plate 11 and the volute rear plate 12 are respectively installed on both sides of the volute enclosure 13, thereby forming the volute 1. A main air inlet 100 is provided on the volute front plate 11, and a volute tongue is provided at one end of the volute enclosure 13. The volute enclosure 13, the volute front plate 11 and the volute rear plate 12 form an air outlet 200 at the end of the volute tongue. Among them, the main air inlet 100 is connected with the air inlet on the smoke hood, and the oil smoke enters the volute 1 from the air inlet of the smoke hood through the main air inlet 100 of the volute front plate 11, and then is discharged from the air outlet 200 along the inner wall of the volute enclosure 13 after being accelerated and guided by the impeller 2.

[0049] The centrifugal fan also includes an air guide ring 4 fixedly mounted on the volute front plate 11 to guide the airflow into the fan. The motor 3 is fixedly mounted on the volute rear plate 12 to provide driving force for the fan impeller 2 to rotate.

[0050] Embodiment 3

[0051] In order to improve the oil fume absorption capacity of the centrifugal fan, in the prior art, the volute profile of the volute 1 usually adopts an equiangular spiral line design, which can reduce the air flow turbulence inside the volute 1, reduce flow losses, reduce aerodynamic noise, and improve the oil fume absorption capacity of the centrifugal fan.

[0052] However, the volute profile is designed as an equiangular spiral line, and it is usually assumed that the impeller 2 outlet is circumferentially uniform, without considering the influence of other front-end components of the centrifugal fan on its intake flow. In the case of limited installation space for the centrifugal fan, the volute profile design cannot well conform to the airflow law in the volute 1, and thus there are disadvantages such as flow loss in the volute 1 and obvious aerodynamic noise.

[0053] In order to solve the above problems, this embodiment provides a volute profile design method, such as Figure 4-Figure 5 As shown, the volute profile of the volute 1 is designed as a gradually expanding variable-angle spiral line. The gradually expanding variable-angle spiral line has a continuous change trend of expansion degree from small at the front to large at the back. On the one hand, the height of the overall volute 1 can be kept small by adjusting the upper and lower spaces, which can meet the installation space limitation requirements; on the other hand, the use of a small flow space in the small flow area at the upper end of the volute 1 has little effect on the performance, while the large-flow gas confluence area in the flow channel of the volute 1 has a larger internal flow space, which can effectively reduce the average flow velocity in the area, reduce flow losses, and enhance the drainage and pressure diffusion effect of the volute 1.

[0054] like Figure 4-Figure 5As shown, in order to facilitate understanding of the volute profile design method provided in this embodiment, an XY coordinate system is established with the rotation axis O1 of the impeller 2 as the origin, and the volute profile of the volute 1 is defined as including a first straight line segment AB, a volute tongue profile segment BC, a first curved segment CD, a second curved segment DE and a second straight line segment EF.

[0055] Optionally, the volute tongue-shaped line segment BC is a circular arc segment, the first curved line segment CD is a circular arc segment, and the second curved line segment DE is a spiral line segment.

[0056] The snail tongue line segment BC is an arc segment, the center of which is O2, the angle between the line O1O2 and the X axis is β1, and the radius of the snail tongue line segment BC is R1. Preferably, 65°≤β1≤85°, 8mm≤R1≤12mm.

[0057] The first curve segment CD is an arc segment. The first curve segment CD intersects with the volute tongue line segment BC at point C. The first curve segment CD intersects with the second curve segment DE at point D. The distance between point C and the outlet outer diameter of the impeller 2 is the volute tongue spacing t. In order to maintain better aerodynamic and noise performance. The first curve segment CD near the volute tongue position adopts an arc line to ensure that the starting stage of the variable angle spiral line connected subsequently adopts a smaller characteristic airflow angle design, so as not to cause the volute tongue gap t to be too small, causing a sharp deterioration of aerodynamic performance and noise. Preferably, 10mm≤t≤15mm.

[0058] The second curve segment DE is a spiral segment. For any point G on the second curve segment DE, the length of the line O1G connecting the point and the rotation axis of the impeller 2 is recorded as R, and the rotation angle between the line O1G and the negative direction of the X axis is recorded as The rotation angle between the starting point D of the second curve segment DE and the line O1D connecting the rotation axis of the impeller 2 is 90°, and the rotation angle between the ending point E of the second curve segment DE and the line O1E connecting the rotation axis of the impeller 2 is β2+360°, where β2 is defined as the angle between the O1E line and the negative direction of the X-axis, preferably, 10°≤β2≤30°.

[0059] Among them, the spiral segment of the second curve segment DE satisfies formula 1:

[0060]

[0061] Where D2 is the outlet outer diameter of impeller 2, is the rotation angle between the line O1G connecting any point G on the second curve segment DE and the rotation axis O1 of the impeller 2 and the negative direction of the X axis, is the airflow angle required to be determined when designing the spiral line, where k is the characteristic airflow angle constant, and the second curve segment DE is a gradually expanding variable angle spiral line design, that is, A circumferential rotation angle A continuous monotonic function that varies and whose derivative The logarithmic spiral used in conventional technology is usually That is, the characteristic airflow angle is a constant, that is, an equiangular spiral design.

[0062] For example, the optional function Satisfying formula 2, at this time, Linear change:

[0063]

[0064] For example, the optional function Satisfying formula 3, at this time, Nonlinear changes:

[0065]

[0066] In order to better realize the flow diversion and pressure expansion function inside the volute 1 and keep the height of the volute 1 small, preferably, 3°≤k≤5°, 1°≤f(β2+2π)-f(π / 2)≤3°,

[0067] The angle formed by the first straight line segment AB and the X-axis is α1, and the angle formed by the second straight line segment EF and the X-axis is α2. Under the condition that the vertical space of the volute 1 is limited, in order to effectively improve the airflow expansion effect at the air outlet 200, preferably, 50°≤α2≤70°, 10°≤α2-α1≤20°.

[0068] Embodiment 4

[0069] For the case where the height of the installation space is limited and the height space of the diffusion section at the outlet of the volute 1 is limited, based on the volute profile design method provided in Example 2, this embodiment provides a volute 1, which effectively extends the length of the flow diversion and pressure diffusion section of the volute 1 by increasing the bending angle of the airflow at the outlet of the volute 1, reduces the direct impact of high-speed airflow, and reduces the flow separation close to the volute tongue side.

[0070] like Figure 6As shown, the volute 1 includes a volute front plate 11, a volute rear plate 12 and a volute enclosure 13. The outer edge shapes of the volute front plate 11 and the outer edge shapes of the volute rear plate 12 are both adapted to the outer edge shapes of the volute enclosure 13. The volute front plate 11 and the volute rear plate 12 are respectively installed on both sides of the volute enclosure 13, thereby forming the volute 1. A main air inlet 100 is provided on the volute front plate 11, and a volute tongue is provided at one end of the volute enclosure 13. The volute enclosure 13, the volute front plate 11 and the volute rear plate 12 form an air outlet 200 at the end of the volute tongue. Among them, the main air inlet 100 is connected with the air inlet on the smoke hood, and the oil smoke enters the volute 1 from the air inlet of the smoke hood through the main air inlet 100 of the volute front plate 11, and then is discharged from the air outlet 200 along the inner wall of the volute enclosure 13 after being accelerated and guided by the impeller 2. Preferably, the volute 1 further comprises an outlet flange 14, and the outlet flange 14 is used to be connected to a smoke collecting hood.

[0071] See also Figure 4-Figure 5 , the volute profile refers to the profile trend of the volute shroud 13, and the volute profile includes a first straight segment AB, a volute tongue profile segment BC, a first curved segment CD, a second curved segment DE and a second straight segment EF. The starting point of the first straight segment AB and the end point of the second straight segment EF correspond to the two ends of the air outlet 200 of the volute 1, respectively, and the distance between the two end points is L1. The outer diameter of the impeller 2 outlet is D2, and the maximum height of the volute shroud 13 is H1. Preferably, 250mm≤D2≤350mm, 350mm≤H1≤450mm, and 150mm≤L1≤200mm. It should be noted that the maximum height of the volute shroud 13 is H1, which generally refers to the maximum vertical height of the curved segment of the volute shroud 13.

[0072] The XY coordinate system is established with the rotation axis O1 of the impeller 2 as the reference, the volute tongue line segment BC is an arc segment, the center of which is O2, the angle between the line O1O2 and the X axis is β1, and the radius of the volute tongue line segment BC is R1. Preferably, 65°≤β1≤85°, 8mm≤R1≤12mm.

[0073] like Figure 7 As shown, the axial thickness of the volute 1 (i.e., the thickness of the volute shroud 13) is W1, the maximum height of the volute shroud 13 is H1, and 80mm≤W1≤120mm, the ratio of the thickness to the height of the volute 1 is small, 0.15≤W1 / H1≤0.35, and the volute 1 is thin in the axial direction for easy installation. The profile of the volute shroud 13 is a gradually expanding variable angle spiral line, which can keep the vertical height of the volute 1 unchanged, and gradually increase the expansion degree, so as to better improve the collection, drainage and pressure expansion of the impeller 2 outlet flow by the volute 1.

[0074] like Figure 8As shown, preferably, a motor seat 121 is provided on the volute rear plate 12 for fixing and installing the motor 3 of the centrifugal fan. Optionally, the motor seat 121 and the volute rear plate 12 are an integrally formed structure, which can effectively improve the structural support strength of the impeller 2 rotor during rotation and reduce the vibration response of the fan.

[0075] Optionally, the volute front plate 11 and the volute rear plate 12 are provided with reinforcing ribs 16 to improve the overall structural strength and reduce the vibration response of the fan. Exemplarily, the reinforcing ribs 16 can be a concave-convex embossed structure stamped on the volute front plate 11 and the volute rear plate 12.

[0076] Optionally, at least one of the volute front plate 11, the volute enclosure 13, and the volute rear plate 12 is provided with a plurality of noise reduction through holes 15, and the noise reduction through holes 15 can be used for noise reduction. Furthermore, the volute 1 also includes a noise reduction layer (not shown in the figure), which is provided on the outer wall of the volute 1 and covers the noise reduction through holes 15 to prevent oil smoke from escaping from the noise reduction through holes 15. Of course, in other embodiments, the motor seat 121 is also provided with a plurality of noise reduction through holes 15 for noise reduction, which can further enhance the noise reduction effect without reducing the strength of the supporting structure of the motor 3.

[0077] Note that in the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0078] The above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A volute, characterized in that: The volute profile of the volute (1) comprises a first straight line segment, a volute tongue segment, a first curved line segment, a second curved line segment and a second straight line segment connected in sequence, the second curved line segment being a spiral line segment, an XY coordinate system being set with the rotation axis O1 of the impeller (2) as the origin, an angle β2 between a line connecting the end point of the second curved line segment and the rotation axis O1 of the impeller (2) and the negative direction of the X-axis, and the second curved line segment satisfies the following formula: Wherein, D2 is the outlet outer diameter of the impeller (2), is the rotation angle between the line O1G connecting any point G on the second curve segment and the rotation axis O1 of the impeller (2) and the negative direction of the X axis, is the airflow angle of the helix, k is the characteristic angle constant, 3°≤k≤5°, The circumferential rotation angle A continuously monotonically increasing function of change, And its derivative 1°≤f(β2+2π)-f(π / 2)≤3°.

2. The volute according to claim 1, characterized in that: The volute tongue profile line segment is an arc segment, and the angle between the line O1O2 connecting the center O2 of the volute tongue profile line and the rotation axis O1 of the impeller (2) and the X-axis is β1, and the range of β1 is 65°-85°.

3. The volute according to claim 1, characterized in that: The angle formed by the first straight line segment and the X-axis is α1, and the angle formed by the second straight line segment and the X-axis is α2, wherein 50°≤α2≤70°, and 10°≤α2-α1≤20°.

4. The volute according to claim 1, characterized in that: The outlet outer diameter D2 of the impeller (2) is in the range of 250 mm to 350 mm.

5. The volute according to claim 4, characterized in that: The radius R1 of the snail tongue segment is in the range of 8 mm to 12 mm.

6. The volute according to claim 4, characterized in that: The first curve segment is an arc segment, the first curve segment is tangent to the volute tongue-shaped line segment at point C, the first curve segment is tangent to the second curve segment at point D, the distance between point C and the outlet outer diameter of the impeller (2) is the volute tongue distance t, and the range of the volute tongue distance t is 10 mm-15 mm.

7. The volute according to claim 4, characterized in that: The length of a line connecting the starting point of the first straight line segment and the end point of the second straight line segment is L1, where 150 mm ≤ L1 ≤ 200 mm.

8. The volute according to claim 4, characterized in that: The maximum height of the volute (1) is H1, wherein 350 mm ≤ H1 ≤ 450 mm.

9. A centrifugal fan, characterized in that: It comprises an impeller (2), a motor (3) and a volute according to any one of claims 1 to 8, wherein the impeller (2) and the motor (3) are both arranged in the volute (1).

10. A kitchen appliance, characterized in that: Comprising the centrifugal fan as claimed in claim 9.

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