Air outlet cover of range hood and range hood
By introducing a baffle structure into the range hood's exhaust hood, the noise problem caused by vortices and disturbances in airflow is solved, thereby improving the stability and efficiency of airflow.
Patent Information
- Application Number
- CN202520436358.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-13
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2035-03-13
AI Technical Summary
The exhaust hood of a range hood is prone to creating vortices and disturbances during airflow, resulting in significant aerodynamic noise.
Design an air outlet hood structure, including a circular interface section, a polygonal interface section and an interface transition section, and set a guide plate on the inner wall of the interface transition section to gradually transition the airflow direction and reduce airflow fluctuations and eddies.
The design of the deflector reduces aerodynamic noise and improves the stability and efficiency of airflow.
Smart Images
Figure CN223869299U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of range hood technology, and in particular to a range hood exhaust hood and a range hood. Background Technology
[0002] A range hood is an electrical appliance used in the kitchen, primarily to exhaust cooking fumes, steam, and odors outdoors. The working principle of a range hood is mainly based on aerodynamics; it uses a fan assembly inside the hood to generate negative pressure suction, drawing in and expelling cooking fumes located below the hood.
[0003] The exhaust hood of a range hood connects to the exhaust duct of the fan assembly and the common flue. Typically, the exhaust hood has a square-to-round structure. When the airflow exits from the fan assembly's exhaust duct, its velocity and pressure are both high. As the airflow passes through this square-to-round structure, the internal flow field becomes more complex, resulting in higher fluid velocity and greater aerodynamic noise. In particular, at the inlet and outlet of the exhaust hood, the airflow velocity is relatively unstable, easily undergoing compression and acceleration, which can easily create vortices and disturbances. Utility Model Content
[0004] In view of this, the present application provides an exhaust hood and a range hood to solve at least one problem existing in the background art.
[0005] In a first aspect, embodiments of this application provide an exhaust hood for a range hood, the range hood including a fan assembly and a fan exhaust duct communicating with the fan assembly, wherein airflow flows through the fan exhaust duct to the exhaust hood under the action of the fan assembly; the exhaust hood includes:
[0006] A circular interface segment, one end of which is used to connect to a common flue;
[0007] A polygonal interface segment, one end of which is connected to the outlet of the fan airflow channel;
[0008] An interface transition segment connects the polygonal interface segment and the circular interface segment at its two ends, respectively. The cross-section of the interface transition segment, along the direction from the polygonal interface segment to the circular interface segment, gradually transitions from a polygon corresponding to the polygonal interface segment to a circle corresponding to the circular interface segment.
[0009] A first guide plate is disposed on the inner wall of the interface transition section, and the first guide plate extends towards the circular interface section at the corner position of the polygonal cross-section of the interface transition section.
[0010] In conjunction with the first aspect of this application, in an alternative embodiment, the first guide plate extends toward the central axis of the circular interface segment.
[0011] In conjunction with the first aspect of this application, in an optional embodiment, the bottom end of the first guide plate is connected to the inner wall of the interface transition section, and its top end is a free end. The first guide plate gradually narrows from its bottom end to its top end.
[0012] In conjunction with the first aspect of this application, in an optional embodiment, the interface transition segment has a first length in a first direction, the first direction being the axial direction of the circular interface segment;
[0013] The bottom end of the first guide plate has a second length in its extending direction, the second length being less than or equal to 0.7 times the first length.
[0014] In conjunction with a first aspect of this application, in an alternative embodiment, the top end of the first guide vane has a third length in its extending direction, the third length being less than or equal to 0.5 times the second length.
[0015] In conjunction with the first aspect of this application, in an optional embodiment, the vertical distance between the bottom end and the top end of the first guide plate is a first height, and the first height is less than 10 mm.
[0016] In conjunction with the first aspect of this application, in an alternative embodiment, the outer edge of the first guide vane is provided with a wave shape along its extending direction.
[0017] In conjunction with the first aspect of this application, in an alternative embodiment, the amplitude of the wave shape is less than or equal to 2 mm.
[0018] In conjunction with the first aspect of this application, in an alternative embodiment, the cross-section of the interface transition segment gradually narrows along the direction from the polygonal interface segment to the circular interface segment.
[0019] In conjunction with the first aspect of this application, in an optional embodiment, the polygonal interface segment is provided with a quadrilateral interface adapted to the outlet of the fan air duct, and its corners are rounded; the cross-section of the interface transition segment where it connects with the polygonal interface segment is also correspondingly set as a quadrilateral adapted to the polygonal interface segment, and its corners are rounded.
[0020] In conjunction with the first aspect of this application, in an optional embodiment, there are two first guide plates, which are respectively arranged at two adjacent corners of the polygonal cross-section of the interface transition section and extend toward the circular interface section.
[0021] In conjunction with the first aspect of this application, in an optional embodiment, the air outlet shroud further includes:
[0022] The second guide plate is connected to the inner wall of the interface transition section and is located between the two first guide plates, extending towards the circular interface section. The second guide plate has the same structural requirements as the first guide plate.
[0023] Secondly, embodiments of this application provide a range hood, including an exhaust hood, a fan assembly, and a fan exhaust channel communicating with the fan assembly, according to any embodiment of the first aspect. Airflow flows through the fan exhaust channel under the action of the fan assembly and is then discharged from the exhaust hood.
[0024] In conjunction with the second aspect of this application, in an optional embodiment, the air outlet direction of the fan outlet duct and the air outlet direction of the air outlet shroud form an obtuse angle, the connection area between the fan outlet duct and the air outlet shroud forms a turning duct, and the first guide plate is disposed on the inner wall of the inner bend side of the turning duct.
[0025] The exhaust hood provided in this application embodiment has a first guide plate disposed on the inner wall of the interface transition section, and extends towards the circular interface section at the corner of the polygonal cross-section of the interface transition section. This can weaken the airflow fluctuations caused by the change in the shape of the air duct, reduce the occurrence of eddies and disturbances, and thus reduce wind noise.
[0026] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0027] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0028] Figure 1a This is a side view of the exhaust hood of a range hood provided in an embodiment of this application;
[0029] Figure 1b for Figure 1a A partial cross-sectional view at point CC;
[0030] Figure 2 This is an exploded view of the structure of the range hood provided in the embodiments of this application;
[0031] Figure 3 A three-dimensional structural schematic diagram of the exhaust hood of the range hood provided in the embodiments of this application;
[0032] Figure 4 A plan view of the exhaust hood of a range hood provided in this application embodiment;
[0033] Figure 5 for Figure 4 Schematic diagram of the cross section at point AA;
[0034] Figure 6 for Figure 5 Enlarged view of point B in the middle;
[0035] Figure 7 A schematic diagram of the structure of the first guide plate connected to the inner wall of the polygonal interface segment of the exhaust hood provided in the embodiment of this application;
[0036] Figure 8a A schematic diagram of simulated airflow between the fan outlet channel and the outlet hood when the exhaust hood of the range hood provided in this application embodiment is not equipped with a first guide plate;
[0037] Figure 8b A schematic diagram of simulated airflow between the exhaust hood of the range hood provided in this application embodiment and the exhaust hood. The exhaust hood is equipped with a first guide plate.
[0038] Figure label:
[0039] 100. Range hood;
[0040] 10. Enclosure; 110. Air inlet;
[0041] 20. Fan assembly; 210. Motor; 220. Impeller; 230. Volute; 240. Fan outlet airflow duct;
[0042] 30. Exhaust shroud; 310. Circular interface section; 320. Polygonal interface section; 321. Top corner; 32a. First position; 32b. Second position; 322. Quadrilateral interface; 330. First guide vane; 331. Bottom end; 332. Top end; 333. Wavy shape; 334. First slope; 335. Second slope; 340. Interface transition section; 350. Second guide vane;
[0043] 3a, the interior angle of the first included angle; 3b, the exterior angle of the first included angle. Detailed Implementation
[0044] To make the technical solution and beneficial effects of this utility model more apparent and understandable, a detailed description is provided below by listing specific embodiments. The accompanying drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application pertains.
[0045] In the description of this utility model, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of simplifying the description of this utility model and do not indicate that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. In other words, they should not be construed as limitations on this utility model.
[0046] In this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating the relative importance of the indicated features or the number of indicated technical features. Therefore, a feature specified as "first" or "second" can explicitly indicate that at least one of those features is included. In the description of this utility model, "multiple" means at least two, such as two, three, etc.; "several" means at least one, such as one, two, three, etc., unless otherwise explicitly specified.
[0047] In this utility model, unless otherwise explicitly defined, the terms "installation," "connection," "linking," "fixing," and "setting," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; 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 also refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0048] In this utility model, unless otherwise explicitly defined, the terms "above," "on top of," "above," "over," "below," "below," "below," or "below" for "first feature above second feature" can refer to direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Furthermore, "above," "above," and "over" for "first feature above second feature" can mean the first feature is directly above or diagonally above the second feature, or simply indicates that the horizontal height of the first feature is higher than the horizontal height of the second feature. Similarly, "below," "below," and "below" for "first feature below second feature" can mean the first feature is directly below or diagonally below the second feature, or simply indicates that the horizontal height of the first feature is lower than the horizontal height of the second feature.
[0049] Please refer to Figure 1a and Figure 2 The range hood 100 provided in this application embodiment includes a housing 10, a fan assembly 20, and an exhaust hood 30.
[0050] The fan assembly 20 is installed inside the housing 10, and the air outlet shroud 30 is connected to the air outlet of the fan assembly 20. The housing 10 has an air inlet 110. The fan assembly 20 includes a motor 210, an impeller 220, a volute 230, and a fan outlet flow channel 240. The impeller 220 rotates at high speed under the drive of the motor 210 to collect air into the volute 230, thereby converting mechanical energy into kinetic energy and static pressure potential energy. Furthermore, a negative pressure zone is formed at the air inlet 110 of the housing 10 to draw in the airflow from the air inlet 110. The airflow is accelerated and pressurized in the fan outlet flow channel 240 before being discharged from the air outlet shroud 30.
[0051] Figure 1a The arrows in the diagram illustrate the airflow entering from the air inlet 110 of the housing 10, flowing through the fan assembly 20, and exiting from the air outlet 30.
[0052] When the airflow passes through the exhaust hood 30, the flow field inside the exhaust hood 30 is relatively complex due to its square-to-round structure, resulting in higher fluid velocity and greater start-up noise. At the interface transition section 340 of the exhaust hood 30, the flow velocity is relatively slow, and the fluid exhibits a state of compression and acceleration. At the circular interface section 310 of the exhaust hood 30, there are large vortices and disturbances, which are the main sources of aerodynamic noise.
[0053] Based on this, please refer to Figure 3 This application provides an air outlet shroud 30, which includes a first guide plate 330. The first guide plate 330 is connected to the inner wall of the interface transition section 340 and extends towards the circular interface section 310 at the corner of the polygonal cross-section of the interface transition section 340. The first guide plate 330 can guide the airflow and disperse the relatively concentrated airflow, thereby weakening the airflow fluctuation, improving the airflow stability, and further reducing aerodynamic noise.
[0054] For details, please refer to Figure 1b , Figure 2 and Figure 3 The air outlet shroud 30 includes a circular interface section 310, a polygonal interface section 320, an interface transition section 340, and a first guide plate 330.
[0055] One end of the circular interface section 310 is used to connect to the common flue. One end of the polygonal interface section 320 is connected to the outlet of the fan exhaust duct 240.
[0056] The two ends of the interface transition section 340 are connected to the polygonal interface section 320 and the circular interface section 310, respectively. The cross-section of the interface transition section 340, along the direction from the polygonal interface section 320 to the circular interface section 310, gradually transitions from the polygonal shape corresponding to the polygonal interface section 320 to the circle corresponding to the circular interface section. The airflow flows from the fan outlet duct 240 through the polygonal interface section 320, the interface transition section 340 and the circular interface section 310 in sequence before being discharged into the common flue.
[0057] The first guide plate 330 is connected to the inner wall of the interface transition section 340, and the first guide plate 330 extends towards the circular interface section 310 at the corner of the polygonal cross-section of the interface transition section 340.
[0058] This can be understood as follows: the first guide plate 330 is connected to the first position 32a on the inner wall of the interface transition section 340. The first position 32a corresponds to the apex 321 of the polygonal interface section 320. The first position 32a is the corner position of the polygonal interface section 320. When the airflow passes through the polygonal interface section 320, the airflow is not easy to flow to the first position 32a. By using the first guide plate 330 to guide the airflow, the relatively concentrated airflow can be dispersed, the stability of the airflow can be improved, and the aerodynamic noise can be further reduced.
[0059] In an optional embodiment, there are two first guide plates 330, which are respectively arranged at two adjacent corners of the polygonal cross-section of the interface transition section 340 and extend towards the circular interface section 310.
[0060] Of course, the number of first guide plates 330 can also be one, three or four, with each first guide plate 330 corresponding to one of the apex corners 321 of the polygonal interface segment 320.
[0061] In an optional embodiment, the air outlet shroud 30 further includes a second guide plate 340, which is connected to a second position 32b on the inner wall of the polygonal interface segment 320. The second position 32b corresponds to the straight edge position of the polygonal interface segment 320. The second guide plate 340 has the same structural requirements as the first guide plate 330.
[0062] The second guide plate 340 and the first guide plate 330 are connected to the inner wall of the polygonal interface section 320, which can further disperse the relatively concentrated airflow, improve the stability of airflow, and reduce the occurrence of eddy phenomena.
[0063] Figure 3The diagram shows two first guide plates 330 and one second guide plate 340 provided on the polygonal interface segment 320. The two first guide plates 330 correspond to the two apex corners 321 of the polygonal interface segment 320, respectively, and the second guide plate 340 is located between the two first guide plates 330.
[0064] In one alternative embodiment, please refer to Figure 3 Both the first guide plate 330 and the second guide plate 340 extend toward the central axis of the circular interface section 310. Figure 3 The arrow shown points in the direction of the central axis of the circular interface segment 310.
[0065] In this embodiment, the extension directions of the first guide plate 330 and the second guide plate 340 are both toward the central axis of the circular interface section 310, so as to guide the airflow toward the central area of the circular interface section 310, thereby improving the exhaust efficiency of the airflow and reducing the occurrence of eddy phenomena.
[0066] In one alternative embodiment, please refer to Figure 4 and Figure 5 The bottom end 331 of the first guide plate 330 is connected to the inner wall of the polygonal interface section 320, and the top end 332 of the first guide plate 330 is a free end. The first guide plate 330 gradually narrows from the bottom end 331 to its top end 332.
[0067] It can be understood that in the extension direction of the first guide plate 330, the first guide plate 330 first gradually widens and then gradually narrows. When the airflow flows through the polygonal interface section 320, the gradually widening first guide plate 330 can play a good guiding role for the airflow, and the gradually narrowing first guide plate 330 can guide the airflow to flow quickly to the circular interface section 310.
[0068] In one alternative embodiment, please refer to Figure 3 , Figure 4 and Figure 5 The polygonal interface segment 320 has a first length in the first direction, that is Figure 4 As shown in the diagram, L1 has a first direction that is the axial direction of the circular interface segment 310. The bottom end 331 of the first guide plate 330 is connected to the inner wall of the polygonal interface segment 320. The bottom end 331 of the first guide plate 330 has a second length in its extending direction, that is... Figure 5 As shown in the figure, L2 has a second length range that is less than or equal to 0.7 times the first length.
[0069] In this embodiment, the second length range of the bottom end 331 of the first guide plate 330 can improve the guiding effect on the airflow and enhance the stability of the airflow. When the second length of the bottom end 331 of the first guide plate 330 is greater than 0.7 times the first length, it may affect the airflow movement, thereby causing greater aerodynamic noise.
[0070] In an alternative embodiment, the top end 332 of the first guide vane 330 has a third length in its extending direction, the third length being less than or equal to 0.5 times the second length.
[0071] Please refer to Figure 5 The third length range is less than or equal to 0.5 times the second length to ensure the airflow dispersion effect of the first guide vane 330. When the third length range is greater than 0.5 times the second length, the airflow dispersion effect of the first guide vane 330 is weaker.
[0072] In an optional embodiment, the vertical distance between the bottom end 331 and the top end 332 of the first guide plate 330 is a first height, which is less than 10 mm. The first height being less than 10 mm further ensures the dispersion and guiding effect of the first guide plate 330 on the airflow.
[0073] In an optional embodiment, the outer edge of the first guide plate 330 is provided with a wave shape 333 along the extending direction of the first guide plate 330.
[0074] Please refer to Figure 6 and Figure 7 A first inclined surface 334 and a second inclined surface 335 are formed between the top end 332 and the bottom end 331 of the first guide plate 330. The top end 332, the first inclined surface 334 and the second inclined surface 335 of the first guide plate 330 are provided with a wave shape 333. The outer edge of the wave shape 333 can effectively reduce the frictional resistance when the airflow comes into contact with the first guide plate 330, thereby reducing the energy loss when the airflow moves.
[0075] Furthermore, the amplitude of the wave shape 333 is less than or equal to 2mm, which can further ensure that the airflow generates less frictional resistance when it comes into contact with the first guide plate 330, thereby improving the stability of the airflow.
[0076] In one alternative embodiment, please refer to Figure 3 The polygonal interface section 320 is provided with a quadrilateral interface 322 that is adapted to the air outlet duct 240 of the fan, and the corners of the quadrilateral interface 322 are rounded. The cross section of the interface transition section 340 and the polygonal interface section 320 is also set to be a quadrilateral that is adapted to the polygonal interface section 320, and its corners are rounded.
[0077] In an alternative embodiment, the cross-section of the interface transition segment 340 gradually narrows along the direction from the polygonal interface segment 320 to the circular interface segment 320.
[0078] Please refer to Figure 1a and Figure 1b During use, the fan outlet duct 240 of the fan assembly 20 forms a certain angle with the vertical direction to facilitate the airflow entering the fan assembly 20 from the air inlet 110 of the housing 10, thereby improving the suction effect of the range hood 100. Furthermore, due to factors such as the installation of the exhaust hood 30, the axial direction of the fan outlet duct 240 and the axial direction of the circular interface section 310 form a first angle, that is, Figure 1b The first included angle α is shown in the figure.
[0079] Figure 1b The arrows shown in the diagram illustrate the direction of airflow.
[0080] This can be understood as follows: the airflow exiting the fan outlet duct 240 and entering the polygonal interface section 320 will make a bend. The airflow entering the polygonal interface section 320 will collide with the inner wall corresponding to the outer angle 3b of the polygonal interface section 320 and the first included angle, thus changing the airflow direction and slowing down the flow velocity. Meanwhile, the airflow at the inner wall corresponding to the inner angle 3a of the polygonal interface section 320 and the first included angle is relatively sparse. The airflow entering the polygonal interface section 320 is complex and prone to vortex phenomena. Using the first guide plate 330 and the second guide plate 340 to guide the airflow can disperse the relatively concentrated airflow, thereby improving the stability of the airflow.
[0081] In an optional embodiment, the first guide plate 330 is disposed on the inner wall of the polygonal interface segment 320 corresponding to the inner angle 3a of the first included angle.
[0082] It can be understood that the connection area between the air duct 240 at the fan and the air outlet hood 30 forms a turning air duct, and the first guide plate 330 is located on the inner wall of the inner bend side of the turning air duct.
[0083] Please refer to Figure 3 The polygonal interface section 320 is provided with two first guide vanes 330, which correspond to the two apex corners 321 of the polygonal interface section 320. When the airflow reaches the polygonal interface section 320, the two first guide vanes 330 guide the airflow to the inner angle 3a of the first angle formed by the polygonal interface section 320 and the fan outlet airflow duct 240, that is, the inner bend of the turning airflow duct. This can disperse the relatively concentrated airflow and improve the stability of the airflow.
[0084] The first included angle is an obtuse angle, which can reduce the amplitude of airflow and thus improve the stability of airflow.
[0085] Furthermore, both first guide vanes 330 are inclined towards the middle position of the two guide vanes (that is, Figure 3 The second guide vane (position 340 shown in the figure) is used to improve the airflow guiding effect.
[0086] Please refer to Figure 8a and Figure 8b , Figure 8a This paper presents a simulation diagram of the airflow of the range hood 100 provided in this application embodiment when the first guide plate 330 is not provided. Figure 8b The illustration shows a simulation diagram of the airflow of the range hood 100 provided in this application embodiment after the first guide plate 330 is provided on the inner wall of the polygonal interface section 320.
[0087] Depend on Figure 8a It can be seen that the airflow velocity is relatively slow at the polygonal interface segment 320, especially at the position corresponding to the interior angle 3a of the first included angle, where the airflow is sparse and forms vortices and disturbances. Figure 8b It can be seen that the vortex and disturbance at the air outlet of the air outlet 30 are compared with Figure 8a There is a significant improvement, which not only enhances the stability of airflow but also greatly reduces aerodynamic noise.
[0088] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of this application that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of this application and do not limit the scope of protection of this patent application.
Claims
1. An exhaust hood for a range hood, characterized in that, The range hood includes a fan assembly and a fan outlet duct connecting the fan assembly. Under the action of the fan assembly, airflow flows through the fan outlet duct to the exhaust hood; the exhaust hood includes: A circular interface segment, one end of which is used to connect to a common flue; A polygonal interface segment, one end of which is connected to the outlet of the fan airflow channel; An interface transition segment connects the polygonal interface segment and the circular interface segment at its two ends, respectively. The cross-section of the interface transition segment, along the direction from the polygonal interface segment to the circular interface segment, gradually transitions from a polygon corresponding to the polygonal interface segment to a circle corresponding to the circular interface segment. A first guide plate is disposed on the inner wall of the interface transition section, and the first guide plate extends toward the circular interface section at the corner position of the polygonal cross-section of the interface transition section.
2. The exhaust hood of the range hood according to claim 1, characterized in that, The first guide plate extends toward the central axis of the circular interface segment.
3. The exhaust hood of the range hood according to claim 2, characterized in that, The bottom end of the first guide plate is connected to the inner wall of the interface transition section, and its top end is a free end. The first guide plate gradually narrows from the bottom end to its top end.
4. The exhaust hood of the range hood according to claim 3, characterized in that, The interface transition segment has a first length in a first direction, where the first direction is the axial direction of the circular interface segment; The bottom end of the first guide plate has a second length in its extending direction, the second length being less than or equal to 0.7 times the first length.
5. The exhaust hood of the range hood according to claim 4, characterized in that, The top of the first guide vane has a third length in its extending direction, the third length being less than or equal to 0.5 times the second length.
6. The exhaust hood of the range hood according to claim 4, characterized in that, The vertical distance between the bottom and top of the first guide plate is the first height, which is less than 10mm.
7. The exhaust hood of the range hood according to claim 2, characterized in that, The outer edge of the first guide plate has a wave shape along its extension direction.
8. The exhaust hood of the range hood according to claim 7, characterized in that, The amplitude of the wave shape is less than or equal to 2 mm.
9. The exhaust hood of the range hood according to claim 1, characterized in that, The cross-section of the interface transition section gradually narrows along the direction from the polygonal interface section to the circular interface section.
10. The exhaust hood of the range hood according to claim 1, characterized in that, The polygonal interface segment is provided with a quadrilateral interface that is adapted to the outlet of the fan air duct, and its corners are rounded; the cross section at the junction of the interface transition segment and the polygonal interface segment is also set to a quadrilateral that is adapted to the polygonal interface segment, and its corners are rounded.
11. The exhaust hood of the range hood according to any one of claims 1-10, characterized in that, There are two first guide vanes, which are respectively arranged at two adjacent corners of the polygonal cross-section of the interface transition section and extend towards the circular interface section.
12. The exhaust hood of the range hood according to claim 11, characterized in that, The air outlet shroud also includes: The second guide plate is connected to the inner wall of the interface transition section and is located between the two first guide plates, extending towards the circular interface section. The second guide plate has the same structural requirements as the first guide plate.
13. A range hood, characterized in that, Includes an air outlet hood, a fan assembly, and a fan outlet flow channel connected to the fan assembly as described in any one of claims 1 to 12, wherein airflow flows through the fan outlet flow channel under the action of the fan assembly and is discharged from the air outlet hood.
14. The range hood according to claim 13, characterized in that, The air outlet direction of the fan outlet duct and the air outlet direction of the air outlet hood have an obtuse angle. The connection area between the fan outlet duct and the air outlet hood forms a turning duct. The first guide plate is disposed on the inner wall of the inner bend side of the turning duct.