Air inlet grille, centrifugal fan and range hood

Abstract

The utility model provides an air inlet grille, centrifugal fan and range hood, the air inlet grille is used for centrifugal fan, the volute of centrifugal fan is provided with an air inlet and an air outlet, the air inlet grille is arranged in the air inlet, the air inlet grille comprises an inner connecting piece, an outer connecting piece, an outer connecting piece and an inner connecting piece, the outer connecting piece is annular, the outer connecting piece is arranged outside the inner connecting piece in a sleeving mode, and an annular area is formed between the inner connecting piece and the outer connecting piece; the guide vanes are arranged in the annular area at intervals, each guide vane comprises a first end and a second end which are opposite to each other, the first end is connected with the outer connecting piece, the second end is connected with the inner connecting piece, the annular area is divided into at least three sections in the circumferential direction, and the first end is connected with the second end. And the densities of the guide vanes in the at least three intervals are different. The air inlet grille (1) can enable the air speed distribution in the circumferential direction of the air inlet of the centrifugal fan to be more uniform.

Description

Technical Field

[0001] The utility model relates to the technical field of kitchen equipment, in particular to an air intake grille, a centrifugal fan and a range hood. Background Art

[0002] When the range hood uses a centrifugal fan, the negative pressure value in the centrifugal fan volute is different along the spiral direction of the volute, resulting in uneven negative pressure distribution in the circumferential direction of the air inlet, thereby making the wind speed of the air inlet in the circumferential direction of the centrifugal fan uneven. Utility Model Content

[0003] The embodiments of the present utility model provide an air intake grille, a centrifugal fan and a range hood to at least solve some of the above technical problems existing in the prior art.

[0004] According to a first aspect of an embodiment of the present utility model, an air intake grille is provided for a centrifugal fan, wherein the volute of the centrifugal fan has an air inlet and an air outlet, and the air intake grille is provided at the air inlet, and the air intake grille comprises:

[0005] Internal connectors;

[0006] An outer connecting member, the outer connecting member is annular and is sleeved on the outside of the inner connecting member, forming an annular area between the inner connecting member and the outer connecting member;

[0007] A plurality of guide vanes are arranged at intervals in the annular area, each guide vane includes a first end and a second end opposite to each other, the first end is connected to the outer connecting member, and the second end is connected to the inner connecting member, the annular area is divided into at least three intervals in the circumferential direction, and the density of the guide vanes in at least three intervals is different.

[0008] In an optional embodiment, the density of the guide vanes in at least three of the intervals decreases sequentially along the spiral direction of the volute.

[0009] In an optional embodiment, the angle between the starting line of the interval with the largest density of the guide vanes and the reference line along the direction opposite to the spiral line of the volute is 30°-120°, and the reference line passes through the center of the air intake grille and is parallel to the center line of the air outlet.

[0010] In an optional embodiment, the annular area is divided into three sections in the circumferential direction, and the three sections are sequentially a first section, a second section and a third section along the spiral direction of the volute, and the density of the guide vanes is the highest in the first section.

[0011] In an optional embodiment, the central angle of the first interval is 70°-110°, the central angle of the second interval is 100°-140°, and the central angle of the third interval is 130°-170°.

[0012] In an optional embodiment, the central angles of the first interval, the second interval, and the third interval increase sequentially.

[0013] In an optional embodiment, the angle between two adjacent guide vanes in the first interval is 5°-11°, the angle between two adjacent guide vanes in the second interval is 7°-13°, and the angle between two adjacent guide vanes in the third interval is 9°-15°. The angle between the two guide vanes is the angle between the first ends of the two guide vanes and the center of the annular area.

[0014] In an optional embodiment, the angle between two adjacent guide vanes in the third interval is no greater than 8° compared to the angle between two adjacent guide vanes in the first interval.

[0015] In an optional embodiment, the guide vanes in each of the intervals are evenly distributed.

[0016] According to a second aspect of the embodiment of the present utility model, a centrifugal fan is provided, comprising the air intake grille described in the embodiment of the present utility model.

[0017] According to a third aspect of the embodiment of the present utility model, a range hood is provided, comprising the centrifugal fan described in the embodiment of the present utility model.

[0018] An embodiment of the present invention has the following advantages or beneficial effects:

[0019] The air intake grille of the embodiment of the present invention includes an inner connector and an outer connector that is sleeved on the outer portion of the inner connector. An annular area is formed between the inner connector and the outer connector. A plurality of guide vanes are provided in the annular area. Each guide vane includes a first end and a second end that are opposite to each other. The first end is connected to the outer connector and the second end is connected to the inner connector. The annular area is divided into at least three sections in the circumferential direction. The density of the guide vanes in at least three sections is different. The sections with different guide vane densities can correspond to areas with different negative pressures in the volute. The sections with high guide vane density correspond to areas with high negative pressure, thereby limiting the wind speed entering the fan volute from these areas. The sections with low guide vane density correspond to areas with low negative pressure, making it easier for air to enter from these areas, thereby making the wind speed distribution around the volute air inlet more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other features and advantages of the present invention will become more apparent by describing in detail example embodiments thereof with reference to the accompanying drawings.

[0021] Figure 1 This is a schematic diagram of the structure of an air intake grille applied to a centrifugal fan according to an exemplary embodiment. Figure 1 ;

[0022] Figure 2 This is a schematic diagram of the structure of an air intake grille applied to a centrifugal fan according to an exemplary embodiment. Figure 2 ;

[0023] Figure 3 This is a schematic diagram of a range hood applied to a centrifugal fan according to an exemplary embodiment. Figure 3 .

[0024] Among them, the figure numbers are explained as follows: 1-air intake grille, 11-external connecting part, 12-internal connecting part, 13-guide vane, 14-first section, 15-second section, 16-third section, 2-volute, 21-volute tongue, 22-air inlet, 23-air outlet, 3-air inlet ring, 4-reference line, 5-center line. DETAILED DESCRIPTION

[0025] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. Like reference numerals in the figures represent like or similar structures, and thus their detailed description will be omitted.

[0026] The terms "a", "an", "the", "" are used to indicate that there are one or more elements / components / etc.; the terms "including" and "having" are used to express open-ended inclusion and mean that there may be additional elements / components / etc. in addition to the listed elements / components / etc.

[0027] An embodiment of the present invention provides an air intake grille 1. The air intake grille 1 of the embodiment of the present invention is used for a centrifugal fan. The centrifugal fan includes a volute 2. The volute 2 of the centrifugal fan has an air inlet 22 and an air outlet 23. The air intake grille 1 is arranged at the air inlet 22.

[0028] See also Figures 1 to 3 The air intake grille 1 of the present embodiment includes an inner connector 12, an outer connector 11, and a plurality of guide vanes 13. The outer connector 11 may be annular and is sleeved onto the outer portion of the inner connector 12, forming an annular region between the inner and outer connectors 12 and 11. Multiple guide vanes 13 are spaced apart within the annular region to guide air entering the volute 2 from the annular region. Each guide vane 13 includes a first end and a second end, the first end connected to the outer connector 11 and the second end connected to the inner connector 12. The annular region is divided into at least three sections along the circumference, and the density of the guide vanes 13 in at least three sections varies.

[0029] The density of the guide vanes 13 affects the resistance to the airflow. The interval with a larger density of the guide vanes 13 has a larger resistance to the airflow than the interval with a smaller density. When the air intake grille 1 is assembled on the air inlet of the volute 2, the intervals with different densities of the guide vanes 13 can be made to correspond to areas with different negative pressures in the volute 2. The intervals with a large density of the guide vanes 13 correspond to areas with a larger negative pressure, limiting the wind speed from this area into the fan volute 2. The intervals with a smaller density of the guide vanes 13 correspond to areas with a smaller negative pressure, making it easier for air to enter from this area, thereby making the wind speed distribution in the circumference of the air inlet of the volute 2 more uniform, improving the oil fume extraction effect, and enhancing the user experience.

[0030] The greater the negative pressure inside the air inlet, the greater the pressure difference between the inside and outside of the air inlet; the smaller the negative pressure inside the air inlet, the smaller the pressure difference between the inside and outside of the air inlet. When the air inlet is not provided with an air inlet grille 1, or when the guide vanes 13 of the air inlet grille 1 are evenly distributed, the area with a larger negative pressure inside the air inlet has a larger wind speed of the air entering the volute 2 due to the larger pressure difference between the inside and outside, resulting in a better smoking effect. The area with a smaller negative pressure inside the air inlet has a smaller wind speed of the air entering the volute 2 due to the smaller pressure difference between the inside and outside, resulting in a poor smoking effect. The uneven wind speed around the air inlet leads to a poor overall smoking effect. The air inlet grille 1 of the embodiment of the present invention can adjust the wind speed of the air inlet so that the wind speed around the air inlet tends to be consistent, thereby improving the uneven air intake.

[0031] In the embodiment of the present invention, the inner connecting member 12 may be annular, cylindrical or columnar.

[0032] See also Figure 2 and Figure 3 The annular region is divided into at least three sections circumferentially, each of which can be approximately fan-shaped. The at least three sections are sequentially connected to form the annular region, with the end position of one section corresponding to the start position of the next section along the spiral line of the volute 2. For ease of understanding, the start and end positions of each section can be substantially located on the diameter of the annular region. In specific implementations, two adjacent sections can also be separated by a guide vane 13.

[0033] In the embodiment of the present invention, the direction in which the cross-sectional area of ​​the volute 2 increases is the helical direction, and the direction in which the cross-sectional area decreases is the counter-helical direction.

[0034] The negative pressure within the air inlet of the volute 2 decreases along the spiral direction of the volute 2. The air intake grille 1 can be positioned at the air inlet based on the distribution of negative pressure, so that sections with a higher density of guide vanes 13 correspond to areas with higher negative pressure, and sections with a lower density of guide vanes 13 correspond to areas with lower negative pressure. For example, if the annular region is divided into three sections, the density of guide vanes 13 decreases in the first section 14, the second section 15, and the third section 16. The density of guide vanes 13 decreases in the first section 14, the second section 15, and the third section 16. When the air intake grille 1 is positioned at the air inlet of the volute 2, the negative pressure within the air inlet corresponding to the first section 14 is the highest, the second section 15 is the second lowest, and the third section 16 is the lowest.

[0035] In some embodiments, see Figure 2 and Figure 3 The density of the guide vanes 13 in at least three sections decreases sequentially along the spiral direction of the volute 2. When the air intake grille of the present invention is installed on the air inlet, the density of the guide vanes 13 in different sections can be adapted to the changes in negative pressure within the air inlet, so that the wind speed around the circumference of the air inlet tends to be consistent. Of the at least three sections, the density of the guide vanes 13 can be greatest within the first section 14. Along the spiral direction of the volute 2, the sections are sequentially named and distinguished, such as the first section 14, the second section 15, and the third section 16. The negative pressure within the volute 2 gradually decreases along the spiral direction, and the density of the guide vanes 13 in at least three sections also decreases sequentially along the spiral direction. Sections with higher density correspond to areas with higher negative pressure, resulting in greater resistance to airflow entering these areas and a greater reduction in wind speed. Sections with lower density correspond to sections with lower negative pressure, resulting in less resistance to airflow entering these areas and a smaller reduction in wind speed, thereby tending to make the wind speed around the circumference of the air inlet tend to be consistent. The at least three intervals may be a first interval 14 , a second interval 15 , and a third interval 16 , etc., according to the density from large to small. The density of the guide vanes 13 in the first interval 14 is the highest.

[0036] In some embodiments, see Figure 3The angle a between the starting line of the interval with the highest guide vane 13 density and the reference line 4, along the spiral direction counter to the volute 2, is 30°-120°. The reference line 4 passes through the center of the air intake grille 1 and is parallel to the centerline 5 of the air outlet 23. For example, when the guide vane 13 density in the first interval 14 of at least three intervals is the highest, the annular area is divided into at least three intervals by rotating 30°-120° from the reference line 4 along the spiral direction as the starting line of the first interval 14. This allows the negative pressure within the areas corresponding to each interval to gradually decrease starting from the first interval 14. By adjusting the guide vanes 13 with different densities, the wind speed in the circumferential direction of the air inlet is made more consistent. In exemplary embodiments, the angle between the starting line of the first interval 14 and the reference line 4 can also be 40°-100°, 50°-90°, or 60°-80°. In a specific implementation, the angle between the starting line of the first interval 14 and the reference line 4 may also be 35°, 45°, 55°, 65°, 70°, 75°, 85°, 95°, 110°, etc. In the embodiment of the present disclosure, the annular area can be divided into multiple intervals by detecting the negative pressure at multiple points around the air inlet.

[0037] In an embodiment of the present invention, the annular area can be divided into three intervals, four intervals, five intervals, six intervals, seven intervals, or even more intervals in the circumferential direction. The more intervals the annular area is divided into in the circumferential direction, the finer the adjustment of the wind speed.

[0038] In some embodiments, see Figure 2 and Figure 3 The annular area is divided into three sections in the circumferential direction. These sections are, in order along the spiral direction of the volute 2, a first section 14, a second section 15, and a third section 16. The density of the guide vanes 13 in the first section 14 is the highest, the density of the guide vanes 13 in the second section 15 is the second highest, and the density of the guide vanes 13 in the third section 16 is the lowest. Accordingly, the negative pressure in the internal area of ​​the volute 2 corresponding to the first section 14 is the highest, the negative pressure in the internal area corresponding to the second section 15 is the second highest, and the negative pressure in the internal area corresponding to the third section is the lowest.

[0039] In an embodiment of the present invention, the negative pressure in the area corresponding to different intervals of the air intake grille in the volute 2 can be the average negative pressure of the area, the negative pressure at the center of the area, or other specific negative pressure that can express the negative pressure conditions in different areas.

[0040] In the embodiment of the present invention, the annular area can be divided into at least three even sections, or the annular area can be divided into at least three uneven sections, or some of the at least three sections divided into the annular area can be of the same size.

[0041] In the exemplary embodiment, see Figure 2 and Figure 3The at least three sections of the annular region may be arranged in descending order of the density of the guide vanes 13. The density of the guide vanes 13 in the first section 14 is the highest, and the area of ​​the first section 14 is the smallest.

[0042] In an embodiment of the present invention, at least three intervals divided by the annular area can be approximately fan-shaped, and the size range of no interval can be limited by the central angle. All intervals constitute an annular area, and the sum of the central angles of all intervals is 360°.

[0043] In some embodiments, see Figure 3 The central angle θ1 of the first interval 14 is 70°-110°, the central angle θ2 of the second interval 15 is 100°-140°, and the central angle θ3 of the third interval 16 is 130°-170°. Dividing the three intervals according to this range can make the wind speed at the air inlet 22 more uniform in the circumferential direction. In an exemplary embodiment, the central angle θ1 of the first interval 14 can be 75°, 80°, 85°, 90°, 95°, 100°, or 105°, the central angle θ2 of the second interval 15 can be 105°, 110°, 115°, 120°, 125°, 130°, or 135°, and the central angle θ3 of the third interval 16 can be 135°, 140°, 145°, 150°, 155°, 160°, or 165°. The central angle values ​​of each interval can be integers or non-integers within the above respective intervals.

[0044] In some embodiments, the central angles of the at least three circumferentially divided sections of the annular area increase as the density of guide vanes 13 within each section decreases. The smaller the central angle, the smaller the area of ​​the section and the smaller the proportion of the annular area it occupies. The central angle of each section is correlated with the density of guide vanes 13: the section with the highest density of guide vanes 13 has the smallest central angle, while the section with the lowest density of guide vanes 13 has the largest central angle. This allows the annular area to be divided into fewer sections, achieving uniform wind speed around the circumference of the air inlet.

[0045] In the exemplary embodiment, the annular region is divided into a first section 14, a second section 15, and a third section 16. The density of the guide vanes 13 in the three sections increases with the central angles of the first section 14, the second section 15, and the third section 16. The first section 14, the second section 15, and the third section 16 are substantially fan-shaped. As the central angles of the first section 14, the second section 15, and the third section 16 increase, the areas of the first section 14, the second section 15, and the third section 16 increase.

[0046] In the embodiment of the present invention, the guide vanes 13 are basically arranged along the radius of the annular area, and the density of the guide vanes 13 can be expressed by the angle between two adjacent guide vanes 13. The larger the angle between two adjacent guide vanes 13, the smaller the density of the guide vanes 13, and the smaller the angle between two adjacent guide vanes 13, the greater the density of the guide vanes 13.

[0047] In some embodiments, see Figure 2 The included angle β1 between two adjacent guide vanes 13 in the first interval 14 can be 5°-11°, the included angle β2 between two adjacent guide vanes 13 in the second interval 15 can be 7°-13°, and the included angle β3 between two adjacent guide vanes 13 in the third interval 16 can be 9°-15°. The included angle between two guide vanes 13 is the angle between the first ends of the two guide vanes 13 and the center of the annular region. β1, β2, and β3 are each set within their respective angle ranges, with β1 < β2 < β3, ensuring that the wind speed around the air inlet is consistent. In an exemplary embodiment, the included angle β1 between two adjacent guide vanes 13 in the first interval 14 may be 6°, 7°, 8°, 9°, 10°, or any integer or non-integer angle within the range of 5°-11°; the included angle β2 between two adjacent guide vanes 13 in the second interval 15 may be 8°, 9°, 10°, 11°, 12°, or any integer or non-integer angle within the range of 7°-13°; and the included angle β3 between two adjacent guide vanes 13 in the third interval 16 may be 10°, 11°, 12°, 13°, 14°, or any integer or non-integer angle within the range of 9°-15°.

[0048] In some embodiments, the angle β3 between two adjacent guide vanes 13 in the third interval 16 is not greater than 8° compared to the angle β1 between two adjacent guide vanes 13 in the first interval 14, that is, β3-β1≤8°. By controlling the maximum density and the minimum density, the guide vanes 13 can guide the air while adjusting the wind speed to be consistent, and the air intake of the air inlet can be ensured.

[0049] In some embodiments, the guide vanes 13 in each interval may be evenly distributed. Of course, the guide vanes 13 in each interval may also be unevenly distributed.

[0050] In some embodiments, the guide vanes 13 may be planar or curved. The guide vanes 13 may be tilted to form a spiral flow of air entering the volute 2. The surface of the curved guide vanes 13 may be formed by circular arcs, Bezier curves, or multiple curves.

[0051] Under high back pressure, the backflow on one side of the volute tongue 21 of the centrifugal fan increases, and the volute tongue 21 causes most of the air to flow out from the air outlet 23, and a small amount of air enters the next expansion process. The part of the air that repeatedly enters the next expansion process increases the air intake resistance of the area, making the air intake volume of the area the lowest. Taking the air intake grille 1 divided into three sections along the circumferential direction as an example, this area corresponds to the third section 16 of the air intake grille 1, and the end position of the third section 16 is the starting position of the first section 14. The area corresponding to the first section 14 has the largest air intake volume due to uniform expansion, and the area corresponding to the second section 15 is affected by the backflow of the air outlet 23, and the air intake volume is smaller than that of the first section 14.

[0052] Without the air intake grille of the present invention, the measured wind speed in the area corresponding to the first section 14 is 3-3.7 m / s, the measured wind speed in the area corresponding to the second section 15 is 2.5-3 m / s, and the measured wind speed in the area corresponding to the third section 16 is 1.2-2 m / s. The density of the guide vanes 13 in the first section 14 of the air intake grille 1 of the present invention is the highest, followed by the second section 15, and the lowest in the third section 16. When the air intake grille 1 is installed at the air inlet, the first section 14 faces the area with a wind speed of 3-3.7 m / s, the second section 15 faces the area with a wind speed of 2.5-3 m / s, and the third section 16 faces the area with a wind speed of 1.2-2 m / s. In the first interval 14, the guide vanes 13 are evenly distributed, with the angle between adjacent guide vanes 13 being β1, where β1∈[5°, 11°]. In the second interval 15, the guide vanes 13 are evenly distributed, with the angle between adjacent guide vanes 13 being β2, where β2∈[7°, 13°]. In the third interval 16, the guide vanes 13 are evenly distributed, with the angle between adjacent guide vanes 13 being β3, where β3∈[9°, 15°], where β1<β2<β3 and β3-β1<8°. After installing the air intake grille 1 according to the present invention, the measured wind speeds in the three intervals ranged from 2.3 to 2.8 m / s, significantly improving uniformity.

[0053] The embodiment of the present utility model provides a centrifugal fan, comprising the air intake grille 1 of the embodiment of the present utility model.

[0054] The centrifugal fan comprises a volute 2 and an impeller arranged in the volute 2. The volute 2 has an air inlet and an air outlet 23. The air inlet grille 1 of the embodiment of the present invention is arranged at the air inlet.

[0055] The centrifugal fan further comprises an air inlet ring 3, which is provided at the air inlet, and the air inlet grille 1 may be connected to the air inlet ring 3. In a specific implementation, the outer connecting member 11 of the air inlet grille 1 is connected to the air inlet ring 3 by screws.

[0056] The air intake grille 1 and the air intake ring 3 may also be an integral structure. In the exemplary embodiment, the air intake ring 3 serves as the outer connecting member 11 of the air intake grille 1 , and the first end of the guide vane 13 is connected to the air intake ring 3 .

[0057] An embodiment of the present utility model provides a range hood, comprising a centrifugal fan according to the embodiment of the present utility model.

[0058] In some embodiments, the range hood of the embodiment of the present invention can be a split range hood. The bellows of the split range hood is installed vertically with the centrifugal fan inside, with one part installed on the ceiling and the other part installed inside the cabinet. The noise source is placed upwards, away from the user, thereby improving the kitchen sound environment and facilitating cleaning.

[0059] In some embodiments, the range hood of the present invention includes a bellows, a centrifugal fan is provided in the bellows, and the bellows is connected to the smoke collection hood via a telescopic smoke pipe.

[0060] In some embodiments, a smoke collecting flap is provided on the smoke collecting hood.

[0061] In the embodiments of the present invention, the term "plurality" refers to two or more, unless otherwise specified. Terms such as "installed," "connected," and "fixed" should be interpreted broadly. For example, "connected" can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art will understand the specific meanings of these terms in the embodiments of the present invention based on the specific circumstances.

[0062] In the description of the embodiments of the present invention, it is necessary to understand that the terms "upper" and "lower" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the embodiments of the present invention.

[0063] Throughout this specification, terms such as "one embodiment" and "a preferred embodiment" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0064] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations of the present invention are possible. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An air intake grille (1) for a centrifugal fan, wherein a volute (2) of the centrifugal fan has an air inlet (22) and an air outlet (23), and the air intake grille (1) is arranged at the air inlet (22), characterized in that: The air intake grille (1) comprises: Internal connecting member (12); An external connecting member (11), the external connecting member (11) is annular, the external connecting member (11) is sleeved outside the internal connecting member (12), and an annular area is formed between the internal connecting member (12) and the external connecting member (11); A plurality of guide vanes (13) are arranged at intervals in the annular area, each of the guide vanes (13) includes a first end and a second end opposite to each other, the first end is connected to the outer connecting member (11), and the second end is connected to the inner connecting member (12), the annular area is divided into at least three sections in the circumferential direction, and the density of the guide vanes (13) in at least three sections is different.

2. The air intake grille (1) according to claim 1, characterized in that: The density of the guide vanes (13) in at least three of the intervals decreases sequentially along the spiral direction of the volute (2).

3. The air intake grille (1) according to claim 2, characterized in that: The angle between the starting line of the interval with the highest density of the guide vanes (13) and the reference line (4) is 30°-120° along the direction opposite to the spiral line of the volute (2), and the reference line (4) passes through the center of the air intake grille (1) and is parallel to the center line (5) of the air outlet (23).

4. The air intake grille (1) according to claim 2, characterized in that: The annular area is divided into three sections in the circumferential direction. The three sections are sequentially a first section (14), a second section (15) and a third section (16) along the spiral direction of the volute (2). The density of the guide vanes (13) in the first section (14) is the highest.

5. The air intake grille (1) according to claim 4, characterized in that: The central angle of the first interval (14) is 70°-110°, the central angle of the second interval (15) is 100°-140°, and the central angle of the third interval (16) is 130°-170°.

6. The air intake grille (1) according to claim 4, characterized in that: The central angles of the first interval (14), the second interval (15) and the third interval (16) increase successively.

7. The air intake grille (1) according to claim 4, characterized in that: The included angle between two adjacent guide vanes (13) in the first interval (14) is 5°-11°, the included angle between two adjacent guide vanes (13) in the second interval (15) is 7°-13°, and the included angle between two adjacent guide vanes (13) in the third interval (16) is 9°-15°. The included angle between the two guide vanes (13) is the included angle between the first ends of the two guide vanes (13) and the line connecting the center of the annular area.

8. The air intake grille (1) according to claim 7, characterized in that: The included angle between two adjacent guide vanes (13) in the third interval (16) is no greater than 8° compared to the included angle between two adjacent guide vanes (13) in the first interval (14).

9. The air intake grille (1) according to claim 1, characterized in that: The guide vanes (13) in each of the intervals are evenly distributed.

10. A centrifugal fan, characterized in that: Comprising the air intake grille (1) according to any one of claims 1 to 9.

11. A range hood, characterized in that: Including the centrifugal fan according to claim 10.

Images