Centrifugal fan and range hood

Abstract

The invention relates to a centrifugal fan and a range hood. The centrifugal fan comprises an air bellow; the volute is arranged in the air bellow; the impeller is rotatably arranged in the volute; the impeller and the air bellow meet a relational expression shown in the specification; wherein D is the diameter of the impeller; pi is the circumference ratio; the upper limit m1 of the aspect ratio L / H of the inner flow channel of the air bellow is between 1.05 and 1.15; the lower limit m0 of the aspect ratio L / H of the inner flow channel of the air bellow ranges from 0.85 to 0.95; and the width of the inner flow channel of the air bellow ranges from 380 mm to 420 mm.

Description

Technical Field

[0001] This application relates to the field of range hood technology, and in particular to a centrifugal fan and a range hood. Background Technology

[0002] As people's living standards improve, range hoods have gradually become an indispensable appliance in the kitchen. They are usually installed above the kitchen stove and can extract the fumes generated during cooking, thereby purifying the kitchen environment and improving people's comfort while cooking.

[0003] The core power system of existing range hoods generally uses multi-blade centrifugal fans. This means that the airflow first passes through the impeller and then is collected, pressurized, and guided outdoors by the volute. Therefore, the quality of the fan volute design directly affects the range hood's core performance indicators such as airflow and noise. Traditionally, the design of a range hood involves selecting the impeller inlet / outlet angle and pressure coefficient based on the range hood's overall flow rate Q, static pressure P, and rotational speed n. Further, it determines related parameters such as impeller diameter and depth, and then uses the logarithmic spiral formula or Archimedes' spiral formula to determine the volute's volume and profile. If the centrifugal fan is installed inside the air box and is limited by the size of the airflow channel within the air box, it is usually achieved by cutting one side or proportionally scaling down to meet the requirements of the airflow channel size.

[0004] However, on the one hand, the ideal impeller size, calculated based on parameters such as flow rate and pressure without spatial constraints, often cannot well match the usage scenarios under the limited air box of a range hood. This usually results in an impeller that is too large, and insufficient space is left for the volute to diffuse pressure. On the other hand, the width and height dimensions of the flow channel inside the range hood air box are limited by installation conditions. Different models may have significant differences in the width and height of the flow channel inside the air box. Traditional volutes based on a spiral design generally have similar length and width dimensions in their radial cross-section. Therefore, when the fan is placed inside the limited air box of the range hood, there will be a mismatch between the volute size and the air box. For example, if the volute is too large, the generated volute profile needs further processing, such as cutting one side or scaling the entire volute to meet the air box size limitations. This will lead to performance problems such as reduced efficiency and increased noise. Summary of the Invention

[0005] The existing fan impellers, when designed based on parameters such as pressure and flow rate, do not effectively correlate with the size of the air box within a limited space, resulting in a mismatch between the impeller size and the air box size. This application provides a centrifugal fan and a range hood that can solve the mismatch problem by establishing a correlation between the impeller diameter and the air box size, making full use of the air box space to design a reasonable impeller size, thereby achieving the optimal design of aerodynamic performance and noise.

[0006] According to one aspect of this application, a centrifugal fan is provided, comprising: a wind box; a volute disposed within the wind box; and an impeller rotatably disposed within the volute; wherein the impeller and the wind box satisfy the following relationship:

[0007] Where D is the diameter of the impeller; k0 is the proportionality coefficient; L is the width of the inner flow channel of the wind box; H is the height of the inner flow channel of the wind box; π is pi; m0 and m1 are the lower limit and upper limit of the width-to-height ratio of the inner flow channel of the wind box, respectively.

[0008] In one embodiment of this application, the upper limit of the width-to-height ratio of the inner flow channel of the bellows is between 1.05 and 1.15; the lower limit of the width-to-height ratio of the inner flow channel of the bellows is between 0.85 and 0.95.

[0009] In one embodiment of this application, the width of the inner flow channel of the bellows is between 380 mm and 420 mm.

[0010] In one embodiment of this application, the scaling factor takes a value between 0.25 and 0.4.

[0011] In one embodiment of this application, the angle between the line connecting the farthest upper point of the profile corresponding to the volute and the center of the impeller and the positive Y-axis is between -10° and 20°; the angle between the line connecting the farthest right point of the profile corresponding to the volute and the center of the impeller and the positive X-axis is between -25° and 30°; the angle between the line connecting the farthest lower point of the profile corresponding to the volute and the center of the impeller and the negative Y-axis is between -25° and 45°; and the angle between the line connecting the farthest left point of the profile corresponding to the volute and the center of the impeller and the negative X-axis is between -20° and 30°.

[0012] In one embodiment of this application, the volute and the bellows satisfy the following relationship:

[0013] Wherein: N2 is the distance between the farthest left end of the profile corresponding to the volute and the center of the impeller; a4 is the angle between the connection between the farthest left end of the profile corresponding to the volute and the center of the impeller and the negative X-axis; k1 is the first distance coefficient; L is the width of the inner flow channel of the bellows; m1 is the upper limit of the width-to-height ratio of the inner flow channel of the bellows; H is the height of the inner flow channel of the bellows; D is the diameter of the impeller; s1 is the total value of the gap between the volute and the left and right sides of the bellows.

[0014] In one embodiment of this application, the total gap between the volute and the left and right sides of the bellows is between 0 mm and 40 mm; the first distance coefficient is between 0.65 and 0.8.

[0015] In one embodiment of this application, the volute and the bellows satisfy the following relationship:

[0016] Wherein: N1 is the distance between the farthest right end of the profile corresponding to the volute and the center of the impeller; a2 is the angle between the line connecting the farthest right end of the profile corresponding to the volute and the center of the impeller and the positive direction of the X-axis; L is the width of the inner flow channel of the bellows; N2 is the distance between the farthest left end of the profile corresponding to the volute and the center of the impeller; a4 is the angle between the line connecting the farthest left end of the profile corresponding to the volute and the center of the impeller and the negative direction of the X-axis; s1 is the total value of the gap between the left and right sides of the volute and the bellows.

[0017] In one embodiment of this application, the volute and the bellows satisfy the following relationship: Where: M2 is the distance between the farthest point of the upper end of the profile corresponding to the volute and the center of the impeller; k2 is the second distance coefficient; α0 is the volute tongue clearance coefficient; D is the diameter of the impeller;

[0018] In one embodiment of this application, the cochlear tongue gap coefficient is between 0.05 and 0.1; the second distance coefficient is between 1.1 and 1.5.

[0019] In one embodiment of this application, the centrifugal fan further includes an air outlet plate fixed to the top of the air box and connected to the air outlet of the volute; the distance between the farthest point of the upper end of the profile corresponding to the volute and the air outlet plate is between 10mm and 40mm.

[0020] In one embodiment of this application, the centrifugal fan further includes an air outlet plate fixed to the top of the air box and connected to the air outlet of the volute; the volute and the air box satisfy the following relationship:

[0021] Wherein: M1 is the distance between the farthest point of the lower end of the profile corresponding to the volute and the center of the impeller; a3 is the angle between the line connecting the farthest point of the lower end of the profile corresponding to the volute and the center of the impeller and the negative direction of the Y-axis; k3 is the third distance coefficient; H is the height of the inner flow channel of the wind box; m1 is the upper limit of the width-to-height ratio of the inner flow channel of the wind box; L is the width of the inner flow channel of the wind box; s2 is the minimum value among the distances between the farthest point of the lower end of the profile corresponding to the volute and the bottom wall of the wind box and the distance from the position m1L below the air outlet plate; D is the diameter of the impeller.

[0022] In one embodiment of this application, the minimum value of the distance between the farthest point of the lower end of the profile corresponding to the volute and the bottom wall of the wind box and the distance from the m1L position below the air outlet plate is between 20mm and 70mm; the third distance coefficient is between 0.5 and 0.7.

[0023] According to another aspect of this application, one embodiment of this application provides a range hood, including: any of the centrifugal fans described above; and a smoke collection chamber located below the centrifugal fan and communicating with the air box of the centrifugal fan.

[0024] In summary, the centrifugal fan of this application establishes a relationship between the impeller size and the bellows size, enabling reasonable limitation of the impeller volume based on the bellows size to solve the mismatch problem and achieve optimal aerodynamic performance and noise reduction. Furthermore, the centrifugal fan of this application also sets a range for the width-to-height ratio of the internal flow channel. When the ratio exceeds this range, the impeller volume is considered based on the smaller aspect ratio; otherwise, the volute opening in a certain direction will be limited, affecting the overall diffusion effect and easily causing vortices inside the volute.

[0025] Furthermore, when a volute based on a traditional helical design is placed inside the air box's flow channel, a mismatch between the volute's size and the air box's dimensions can occur. For example, if the volute's radial cross-section is suitable in one direction but exceeds the air box's dimensions in another, local profile cutting or overall scaling is required. This can impair the fan's aerodynamic performance or leave a significant amount of unused space in one direction, preventing the fan from fully realizing its performance potential. The centrifugal fan of this application, however, can establish design relationships based on the air box's flow channel dimensions and impeller dimensions, selecting characteristic positions of the volute's radial cross-section in multiple directions. This addresses the mismatch between the volute's opening degree in various directions and the air box's flow channel, achieving optimized aerodynamic performance and noise reduction. Attached Figure Description

[0026] Figure 1 This is a schematic flowchart illustrating a design method for a centrifugal fan according to an embodiment of this application;

[0027] Figure 2 A flowchart illustrating the volute design steps in the centrifugal fan design method according to the above embodiments of this application is shown.

[0028] Figure 3 This is a perspective view of a range hood according to an embodiment of this application;

[0029] Figure 4 A cross-sectional schematic diagram of a range hood according to the above embodiments of this application is shown;

[0030] Figure 5A schematic diagram of the centrifugal fan in the range hood according to the above embodiments of this application is shown;

[0031] Figure 6 A schematic diagram showing the downward displacement of the volute in the range hood according to the above embodiment of this application is shown.

[0032] Explanation of key component symbols:

[0033] 10. Centrifugal fan; 11. Air box; 12. Volute; 13. Impeller; 14. Air outlet plate; 20. Smoke collection chamber.

[0034] The above description of the main component symbols, together with the accompanying drawings and specific embodiments, provides a further detailed explanation of this application. Detailed Implementation

[0035] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0036] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0039] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0041] Considering that traditional impeller sizes designed based on performance parameters cannot effectively match the internal flow space of the air box, and that most of the range hood fan system is placed inside the air box, the air box size is limited by the user's installation scenario, which is the main factor affecting the impeller size. This leads to a mismatch between the ideal impeller size calculated from parameters such as flow rate and pressure under unrestricted space conditions, necessitating excessive compression of the volute profile to meet installation requirements, resulting in reduced efficiency, increased noise, and other performance issues. Therefore, to solve this problem, this application provides a centrifugal fan, its design method, and a range hood. By establishing a correlation between the impeller diameter and the air box size, it fully utilizes the air box space to design a reasonable impeller volume, solving the mismatch problem and achieving optimal aerodynamic performance and noise reduction.

[0042] Specifically, such as Figure 1 As shown, one embodiment of this application provides a design method for a centrifugal fan, which may include the following steps:

[0043] S100: Construct the relationship between the impeller diameter and the wind box size to obtain the impeller-wind box relationship model;

[0044] S200: Based on the width and height of the inner flow channel of the wind box, the impeller diameter is obtained through this impeller-wind box relationship model;

[0045] S300: Based on the obtained impeller diameter, the volute is designed.

[0046] More specifically, the impeller-box relationship model is as follows: Where D is the impeller diameter; k0 is the proportionality coefficient; L is the width of the inner flow channel of the bellows; H is the height of the inner flow channel of the bellows; π is pi; m0 and m1 are the lower and upper limits of the width-to-height ratio of the inner flow channel of the bellows, respectively.

[0047] It is worth noting that both excessively large and excessively small impeller dimensions within the air box are detrimental. If the impeller is smaller than a certain limit, although the volute opening can be increased to reduce the flow velocity within the volute, the airflow cannot effectively fill the entire volute space, exacerbating flow unevenness. Conversely, if the impeller is larger than the limit, the volute opening is limited, failing to effectively convert the outflow pressure into static pressure, resulting in significant energy loss. Since the speed, flow rate, and pressure of a range hood vary during operation, selecting a single parameter for impeller design only represents a specific operating condition. Furthermore, in actual design, increasing the impeller size is beneficial for noise control and improved start-up performance. Therefore, the centrifugal fan design method of this application first establishes the relationship between the impeller size and the air box size, then obtains the optimal impeller size parameters based on the air box size. This allows for a reasonable impeller size design based on the air box size, resolving the mismatch between the two and achieving optimal aerodynamic performance and noise reduction.

[0048] In addition, the design method of the centrifugal fan in this application also sets a range of width-to-height ratio of the internal flow channel. When the width-to-height ratio exceeds the range, the impeller volume will be considered according to the direction of the smaller side. Otherwise, the opening of the volute in a certain direction will be limited, affecting the overall diffusion effect and easily causing vortices inside the volute.

[0049] Optionally, the upper and lower limits of the width-to-height ratio of the inner flow channel of the bellows satisfy the following: 0.85≤m0≤0.95, 1.05≤m1≤1.15; that is, the upper limit m1 of the width-to-height ratio of the inner flow channel of the bellows is between 1.05 and 1.15; the lower limit m0 of the width-to-height ratio of the inner flow channel of the bellows is between 0.85 and 0.95. Preferably, m0=0.9; m1=1.1. It is understood that the upper and lower limit ranges of the width-to-height ratio of the inner flow channel mentioned in this application are set with reference to the ratio of the width and height of a conventional volute. When the width-to-height ratio exceeds this range, the impeller diameter cannot be constrained according to two dimensions at the same time, because this is because it is easy to cause the impeller diameter to be too large, resulting in the volute being limited in the smaller dimension.

[0050] Optionally, the proportionality coefficient k0 mentioned in this application satisfies: 0.25 ≤ k0 ≤ 0.4; that is, the proportionality coefficient k0 takes a value between 0.25 and 0.4 to control noise while avoiding restriction of the volute opening, thus facilitating the reduction of pressure loss. It is understandable that when the proportionality coefficient k0 is less than 0.25, the impeller volume is smaller relative to the bellows size, resulting in a faster outflow velocity for the same air volume, which is detrimental to noise control; when the proportionality coefficient k0 is greater than 0.4, the space left for the volute is limited, leading to restricted volute opening and an inability to effectively convert the outflow dynamic pressure of the impeller into static pressure, resulting in severe pressure loss.

[0051] It is worth noting that when a volute based on a traditional helical design is placed inside the air box flow channel, a mismatch between the volute's size and the air box can still occur. For example, if the radial cross-section of the volute is suitable in one direction but exceeds the air box size in another, local profile cutting or overall scaling is required. This can impair the aerodynamic performance of the fan, or leave a large amount of unused space in one direction, preventing the full realization of its performance potential. To address this issue, the centrifugal fan design method of this application can establish design relationships based on the flow channel dimensions and impeller dimensions within the air box, selecting characteristic positions of the volute's radial cross-section in multiple directions. This resolves the mismatch between the volute's opening degree in various directions and the flow channel within the air box, achieving optimized aerodynamic performance and noise reduction.

[0052] Specifically, such as Figure 2 and Figure 5 As shown, step S300 in the centrifugal fan design method of this application may include the following steps:

[0053] S310: Based on the radial section of the volute, establish a reference coordinate system O-XY, where the origin O coincides with the impeller center, the X-axis is perpendicular to the height direction of the bellows and takes the direction away from the volute outlet as the positive direction, and the Y-axis is parallel to the height direction of the bellows and takes the direction closer to the volute outlet as the positive direction.

[0054] S320: Select the farthest points at both ends of the projection of each point on the volute profile onto the X-axis and Y-axis respectively, so as to obtain the farthest point P1 at the top end, the farthest point P2 at the right end, the farthest point P3 at the bottom end, and the farthest point P4 at the left end of the volute profile.

[0055] S330: Construct the relationship between each farthest point on the volute-shaped line and the impeller center to obtain the distance model of the farthest point at the top, the farthest point at the right, the farthest point at the bottom, and the farthest point at the left.

[0056] S340: Based on the width and height of the inner flow channel of the bellows and the obtained impeller diameter, the dimensions of the volute profile in the width and height directions are solved by multiple farthest point distance models.

[0057] It is worth noting that, such as Figure 5 As shown, although the furthest points P1 at the top, P2 at the right, P3 at the bottom, and P4 at the left of the volute profile are not necessarily on the X-axis or Y-axis, to avoid severe abrupt changes in the flow channel, the angle α1 between the line connecting the furthest point P1 at the top and the impeller center and the positive direction of the Y-axis is preferably between -10° and 20°; the angle α2 between the line connecting the furthest point P2 at the right and the impeller center and the positive direction of the X-axis is preferably between -25° and 30°; the angle α3 between the line connecting the furthest point P3 at the bottom and the impeller center and the negative direction of the Y-axis is preferably between -25° and 45°; and the angle α4 between the line connecting the furthest point P4 at the left and the impeller center and the negative direction of the X-axis is preferably between -20° and 30°. It is understood that the angles mentioned in this application are positive in the clockwise direction and negative in the counterclockwise direction; for example, as... Figure 5 The included angles α1, α2, α3 and α4 shown are all positive angles.

[0058] Furthermore, within the limited space of the bellows, after determining the impeller diameter, the remaining space constitutes the volute space. The dimensions of the volute profile in the width and height directions are then designed based on this remaining space, such as... Figure 5 As shown, the dimensions of the volute profile in the width direction include the distance N2 between the farthest point P2 at the right end of the volute profile and the center of the impeller, and the distance N2 between the farthest point P4 at the left end of the volute profile and the center of the impeller; the dimensions of the volute profile in the height direction include the distance M1 between the farthest point P3 at the lower end of the volute profile and the center of the impeller, the distance M2 between the farthest point P1 at the upper end of the volute profile and the center of the impeller, and the distance M3 between the farthest point P1 at the upper end of the volute profile and the outlet plate of the centrifugal fan.

[0059] It should be noted that since the farthest point P4 on the left end of the volute profile is close to the volute outlet and the main flow area of ​​the fan inlet, the volute profile is generally designed with the maximum opening side in the width direction first. That is, the distance N2 between the farthest point P4 on the left end and the impeller center is determined first, and then the distance N2 between the farthest point P2 on the right end and the impeller center is determined.

[0060] For example, in one example of this application, the distance model of the farthest left point can be implemented, but is not limited to: ;

[0061] Where: N2 is the distance between the farthest left end point P4 of the volute profile and the impeller center; α4 is the angle between the connection between the farthest left end point P4 and the impeller center and the negative X-axis direction; k1 is the first distance coefficient; L is the width of the inner flow channel of the bellows; m1 is the upper limit of the width-to-height ratio of the inner flow channel of the bellows; H is the height of the inner flow channel of the bellows; D is the impeller diameter; s1 is the total value of the gap between the volute and the left and right sides of the bellows. It can be understood that min mentioned in this application refers to the minimum value, such as min(L, m1H) refers to the minimum value among the product of the upper limit of the width-to-height ratio of the inner flow channel of the bellows and the height of the inner flow channel of the bellows, m1H, and the width L of the inner flow channel of the bellows.

[0062] It is worth noting that although the distance N2 between the farthest point P4 on the left and the impeller center is in the width direction of the volute profile, it is inappropriate to consider the limitation of the volute size in only one direction when the size of the volute in one direction is larger than that in another direction. The farthest point distance model in this application uses min(L, m1H) to consider the size limitations in two directions (including the width and height directions), which can improve the final diffusion effect of the volute and avoid creating a local high-speed airflow zone.

[0063] Furthermore, the total gap s1 between the left and right sides of the volute and the bellows refers to the sum of the horizontal distance between the farthest point P4 on the left end of the volute profile and the left wall of the bellows, and the horizontal distance between the farthest point P2 on the right end of the volute profile and the right wall of the bellows. Preferably, the total gap s1 between the left and right sides of the volute and the bellows is between 0 mm and 40 mm. It is understood that if noise reduction material is provided inside the bellows, the total gap s1 between the left and right sides of the volute and the bellows is usually taken as the maximum value.

[0064] Optionally, the first distance coefficient k1 is taken between 0.65 and 0.8 to reasonably balance the distance N2 between the farthest point P4 on the left end of the volute profile and the impeller center, and the distance N1 between the farthest point P2 on the right end of the volute profile and the impeller center. It is understood that when the first distance coefficient k1 is less than 0.65, the distance N2 between the farthest point P4 on the left end of the volute profile and the impeller center will be too small, affecting the final diffusion effect of the volute; when the first distance coefficient k1 is greater than 0.8, the distance N1 between the farthest point P2 on the right end of the volute profile and the impeller center will be too small, easily creating a local high-speed airflow zone, which is detrimental to noise control.

[0065] Optionally, the distance model of the farthest point on the right is implemented as follows: ;

[0066] Where: N1 is the distance between the farthest point P2 on the right end of the volute profile and the center of the impeller; a2 is the angle between the line connecting the farthest point P2 on the right end and the center of the impeller and the positive direction of the X-axis; L is the width of the inner flow channel of the bellows; N2 is the distance between the farthest point P4 on the left end of the volute profile and the center of the impeller; a4 is the angle between the line connecting the farthest point P4 on the left end and the center of the impeller and the negative direction of the X-axis; s1 is the total value of the clearance between the volute and the bellows on both sides.

[0067] It is worth noting that although the volute profile is composed of three segments (M1, M2, and M3) in the height direction, the distance M2 between the farthest point P1 at the top of the volute profile and the impeller center is located near the volute tongue position, making this a critical location affecting noise. Therefore, the centrifugal fan design method of this application preferably considers the dimension design at this location based on the volute tongue clearance t, where the volute tongue clearance t can be calculated using the empirical formula t=ɑ0D, where 0.05≤ɑ0≤0.1.

[0068] Specifically, the distance model of the farthest point at the top can be implemented as follows: ;

[0069] Where: M2 is the distance between the farthest point P1 at the top of the volute profile and the center of the impeller; k2 is the second distance coefficient; α0 is the volute tongue clearance coefficient; and D is the impeller diameter.

[0070] Preferably, the second distance coefficient k2 is between 1.1 and 1.5, ensuring that the furthest point P1 on the upper end of the volute profile near the volute tongue is controlled within a reasonable range of increase. This prevents the airflow after being diverted by the volute tongue from flowing back into the volute while reducing noise. It is understood that when the second distance coefficient k2 is greater than 1.5, the airflow after being diverted by the volute tongue is more likely to flow back into the volute, affecting the fan efficiency; when the second distance coefficient k2 is less than 1.1, a long, narrow channel will exist on the volute profile near the volute tongue, resulting in high turbulence intensity and increased noise.

[0071] Furthermore, in one example of this application, the distance model to the farthest lower point can be implemented, but is not limited to: ;

[0072] Where: M1 is the distance between the farthest point P3 at the bottom of the volute profile and the center of the impeller; α3 is the angle between the line connecting the farthest point P3 at the bottom and the center of the impeller and the negative direction of the Y-axis; k3 is the third distance coefficient; H is the height of the inner flow channel of the bellows; m1 is the upper limit of the width-to-height ratio of the inner flow channel of the bellows; L is the width of the inner flow channel of the bellows; s2 is the minimum value among the distances between the farthest point P3 at the bottom of the volute profile and the bottom wall of the bellows and the distance from the m1L position below the outlet plate; D is the impeller diameter. It can be understood that min mentioned in this application refers to the minimum value, such as min(H, m1L) which refers to the minimum value among the product of the upper limit of the width-to-height ratio of the inner flow channel of the bellows and the width of the inner flow channel of the bellows, m1L, and the height H of the inner flow channel of the bellows.

[0073] It is worth noting that the distance M1 between the farthest point P3 at the bottom of the volute profile and the impeller center is usually large, requiring consideration of the wind box size limitations. However, when the wind box dimension is larger in one direction than in another, it is inappropriate to consider only the wind box size limitation in one direction. Therefore, the farthest point distance model in this application uses min(H, m1L) to simultaneously consider the size limitations in two directions (including the height and width directions), which can reduce the influence of eddies and backflow, and improve the fan performance.

[0074] Furthermore, the minimum value s2 among the distances between the farthest point P3 at the bottom of the volute profile and the bottom wall of the air box, and the distance m1L below the air outlet plate, refers to the minimum value among the vertical distances between the farthest point P3 at the bottom of the volute profile and the bottom wall of the air box, and the vertical distances between the farthest point P3 at the bottom of the volute profile and the distance m1L below the air outlet plate. Preferably, the minimum value s2 among the distances between the farthest point P3 at the bottom of the volute profile and the bottom wall of the air box, and the distance m1L below the air outlet plate, is between 20mm and 70mm, so as to maintain a certain distance from the lower inlet, or for the arrangement of noise reduction materials.

[0075] Preferably, the third distance coefficient k3 is between 0.5 and 0.7, ensuring that the farthest point P3 at the lower end of the volute profile is controlled within a reasonable reduction range. This ensures sufficient opening at the bottom of the volute while preventing excessively rapid curvature changes in the self-flow direction profile, reducing the risk of vortex generation, and allowing sufficient space for the distance M3 between the farthest point P1 at the upper end of the volute profile and the outlet plate of the fan. It is understandable that when the third distance coefficient k3 is less than 0.5, the area corresponding to the farthest point P3 at the lower end of the volute profile, as the main air intake area of ​​the fan, will have insufficient bottom opening, affecting fan performance. When the third distance coefficient k3 is greater than 0.7, the opening of the bottom area of ​​the volute will expand significantly compared to other areas, resulting in excessively rapid curvature changes in the self-flow direction profile, easily generating vortices. Furthermore, the limited distance M3 between the farthest point P1 at the upper end of the volute profile and the outlet plate of the centrifugal fan severely impacts the flow conversion efficiency at the outlet section.

[0076] It is worth noting that the distance M3 between the farthest point P1 at the top of the volute profile and the outlet plate of the centrifugal fan corresponds to the extension height of the volute outlet section. The length of this section affects the flow conversion efficiency of the outlet section. If the distance M3 is too short, i.e., the extension height of the volute outlet section is too short, the velocity gradient is large, and the volute outlet is closer to the volute tongue, which can easily cause backflow. If the distance M3 is too long, it will affect the design of the volute body profile when the volute height is limited. Preferably, the distance M3 between the farthest point P1 at the top of the volute profile and the outlet plate of the centrifugal fan is between 10mm and 40mm.

[0077] It is worth mentioning that, in one embodiment of this application, a centrifugal fan 10 is further provided, which can be obtained by the above-described centrifugal fan design method.

[0078] Specifically, such as Figures 4 to 6 As shown, the centrifugal fan 10 may include a wind box 11, a volute 12 disposed within the wind box 11, and an impeller 13 rotatably disposed within the volute 12.

[0079] More specifically, such as Figures 4 to 6 As shown, the impeller 13 and the bellows 11 satisfy the following relationship: Where D is the diameter of impeller 13; k0 is the proportionality coefficient; L is the width of the inner flow channel of wind box 11; H is the height of the inner flow channel of wind box 11; π is pi; m0 and m1 are the lower limit and upper limit of the width-to-height ratio of the inner flow channel of wind box 11, respectively.

[0080] Optionally, such as Figure 4 As shown, the centrifugal fan 10 also includes an air outlet plate 14 fixed to the top of the air box 11 and connected to the air outlet of the volute 12.

[0081] It is worth noting that the inner flow channel width L mentioned in this application refers to the distance between the inner surfaces of the left and right sides of the air box when facing the air inlet of the fan. Figure 4 As shown. Optionally, the width L of the inner flow channel of the fan box 11 is between 380mm and 420mm. It is understandable that as range hoods are increasingly trending towards thinner and smaller designs to meet the needs of kitchen space coordination and aesthetics: when the inner flow channel width L exceeds 420mm, although the diameter of the impeller 13 can be increased to improve the fan performance, the overall size of the fan structure will increase accordingly. In cases where the installation space is limited or needs to be embedded in a cabinet, it may lead to the inability to install or difficulty in installation; conversely, when the inner flow channel width L is less than 380mm, although the installation space limitation can be met, the diameter of the impeller 13 is limited, which will cause a significant decrease in fan performance, thereby affecting the smoke extraction effect.

[0082] Furthermore, the internal flow channel height H mentioned in this application refers to the unobstructed flow channel height that the range hood can provide, specifically the distance between the top plane and the ultimate lower plane parallel to the top plane. The top plane typically refers to the plane where the air vent plate 14 is located; the ultimate lower plane typically refers to the plane where the lowest point of the volute 12 is located when the volute 12 moves downwards in its original posture and first rigidly contacts any other component of the range hood (such as the smoke collection chamber 20). Figure 6 As shown. It is understood that, for lift-type range hoods, the internal flow channel height H mentioned in this application is the distance between the top plane and the lower limit plane when the range hood is in a non-working state.

[0083] Optionally, the upper limit m1 of the width-to-height ratio of the inner flow channel of the wind box 11 is between 1.05 and 1.15; the lower limit m0 of the width-to-height ratio of the inner flow channel of the wind box 11 is between 0.85 and 0.95.

[0084] Optionally, the proportionality coefficient k0 takes a value between 0.25 and 0.4.

[0085] Optionally, such as Figure 5 As shown, the angle α1 between the line connecting the farthest point P1 at the top of the profile corresponding to the volute 12 and the center of the impeller 13 and the positive direction of the Y-axis is between -10° and 20°; the angle α2 between the line connecting the farthest point P2 at the right end of the profile corresponding to the volute 12 and the center of the impeller 13 and the positive direction of the X-axis is between -25° and 30°; the angle α3 between the line connecting the farthest point P3 at the bottom of the profile corresponding to the volute 12 and the center of the impeller 13 and the negative direction of the Y-axis is between -25° and 45°; and the angle α4 between the line connecting the farthest point P4 at the left end of the profile corresponding to the volute 12 and the center of the impeller 13 and the negative direction of the X-axis is between -20° and 30°.

[0086] In one example of this application, such asFigures 4 to 6 As shown, the volute 12 and the bellows 11 can satisfy the following relationship: Where: N2 is the distance between the farthest left end point P4 of the profile corresponding to the volute 12 and the center of the impeller 13; α4 is the angle between the connection between the farthest left end point P4 and the center of the impeller 13 and the negative X-axis direction; k1 is the first distance coefficient; L is the width of the inner flow channel of the bellows 11; m1 is the upper limit of the width-to-height ratio of the inner flow channel of the bellows 11; H is the height of the inner flow channel of the bellows 11; D is the diameter of the impeller 13; s1 is the total value of the gap between the volute 12 and the left and right sides of the bellows 11.

[0087] Optionally, the total gap s1 between the left and right sides of the volute 12 and the bellows 11 is between 0 mm and 40 mm; the first distance coefficient k1 is between 0.65 and 0.8.

[0088] In one example of this application, such as Figures 4 to 6 As shown, the volute 12 and the bellows 11 can also satisfy the following relationship: Where: N1 is the distance between the farthest point P2 on the right end of the profile corresponding to the volute 12 and the center of the impeller 13; a2 is the angle between the line connecting the farthest point P2 on the right end and the center of the impeller 13 and the positive direction of the X-axis; L is the width of the inner flow channel of the bellows 11; N2 is the distance between the farthest point P4 on the left end of the profile corresponding to the volute 12 and the center of the impeller 13; a4 is the angle between the line connecting the farthest point P4 on the left end and the center of the impeller 13 and the negative direction of the X-axis; s1 is the total value of the gap between the volute 12 and the bellows 11 on both sides.

[0089] In one example of this application, such as Figure 5 As shown, the volute 12 and the bellows 11 can also satisfy the following relationship: Where: M2 is the distance between the farthest point P1 at the top of the profile corresponding to the volute 12 and the center of the impeller 13; k2 is the second distance coefficient; α0 is the volute tongue clearance coefficient; and D is the diameter of the impeller 13.

[0090] Optionally, the volute tongue gap coefficient α0 is between 0.05 and 0.1; and the second distance coefficient k2 is between 1.1 and 1.5.

[0091] Optionally, the distance M3 between the farthest point P1 at the top of the profile corresponding to the volute 12 and the air outlet plate 14 is between 10mm and 40mm.

[0092] In one example of this application, such as Figures 4 to 6 As shown, the volute 12 and the bellows 11 can also satisfy the following relationship: Where: M1 is the distance between the farthest point P3 at the bottom of the profile corresponding to the volute 12 and the center of the impeller 13; a3 is the angle between the line connecting the farthest point P3 at the bottom and the center of the impeller 13 and the negative direction of the Y-axis; k3 is the third distance coefficient; H is the height of the inner flow channel of the wind box 11; m1 is the upper limit of the width-to-height ratio of the inner flow channel of the wind box 11; L is the width of the inner flow channel of the wind box 11; s2 is the minimum value among the distances between the farthest point P3 at the bottom of the profile corresponding to the volute 12 and the bottom wall of the wind box 11 and the distance from the position m1L below the outlet plate 14; D is the diameter of the impeller 13.

[0093] Optionally, the minimum value s2 of the distance between the farthest point P3 at the lower end of the profile corresponding to the volute 12 and the bottom wall of the wind box 11 and the position m1L below the air outlet plate 14 is between 20mm and 70mm; the third distance coefficient k3 is between 0.5 and 0.7.

[0094] It is worth mentioning that in another embodiment of this application, such as Figures 3 to 6 As shown, this application further provides a range hood, which may include the aforementioned centrifugal fan 10 and a smoke collection chamber 20 located below the centrifugal fan 10 and communicating with the air box 11 of the centrifugal fan 10. It is understood that the range hood of this application may also include, but is not limited to, a control panel, a water tank, or a water collection box to assist in completing the smoke extraction function; these will not be elaborated upon here.

[0095] In addition, the range hood of this application may also include a control box communicatively connected to the centrifugal fan 10, which can be controlled by a voice module. The control box is equipped with a controller, a voice receiving module, and a voice parsing module. The voice receiving module receives user commands, and the voice parsing module parses the commands. Based on the parsed commands, the controller controls the range hood to perform corresponding operations, thereby realizing intelligent control of the range hood and improving the user experience.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are quite specific and detailed. However, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A centrifugal fan, characterized in that, include: bellows; The volute is located inside the bellows; as well as The impeller is rotatably disposed within the volute. The impeller and the bellows satisfy the following relationship: Where D is the diameter of the impeller; k0 is the proportionality coefficient; L is the width of the inner flow channel of the wind box; H is the height of the inner flow channel of the wind box; π is pi; m0 and m1 are the lower limit and upper limit of the width-to-height ratio of the inner flow channel of the wind box, respectively. The upper limit of the width-to-height ratio of the inner flow channel of the wind box is between 1.05 and 1.15; the lower limit of the width-to-height ratio of the inner flow channel of the wind box is between 0.85 and 0.95; and the width of the inner flow channel of the wind box is between 380mm and 420mm.

2. The centrifugal fan according to claim 1, characterized in that, The proportionality coefficient ranges from 0.25 to 0.

4.

3. The centrifugal fan according to claim 1, characterized in that, The angle between the line connecting the farthest upper point of the profile corresponding to the volute and the center of the impeller and the positive Y-axis is between -10° and 20°; the angle between the line connecting the farthest right point of the profile corresponding to the volute and the center of the impeller and the positive X-axis is between -25° and 30°; the angle between the line connecting the farthest lower point of the profile corresponding to the volute and the center of the impeller and the negative Y-axis is between -25° and 45°; and the angle between the line connecting the farthest left point of the profile corresponding to the volute and the center of the impeller and the negative X-axis is between -20° and 30°.

4. The centrifugal fan according to any one of claims 1 to 3, characterized in that, The volute and the bellows satisfy the following relationship: Where: N2 is the distance between the farthest left end of the profile corresponding to the volute and the center of the impeller; α4 is the angle between the connection between the farthest left end of the profile corresponding to the volute and the center of the impeller and the negative X-axis; k1 is the first distance coefficient; L is the width of the inner flow channel of the bellows; m1 is the upper limit of the width-to-height ratio of the inner flow channel of the bellows; H is the height of the inner flow channel of the bellows; D is the diameter of the impeller; s1 is the total value of the gap between the volute and the left and right sides of the bellows. The total gap between the volute and the left and right sides of the bellows is between 0 mm and 40 mm.

5. The centrifugal fan according to claim 4, characterized in that, The first distance coefficient takes a value between 0.65 and 0.

8.

6. The centrifugal fan according to any one of claims 1 to 3, characterized in that, The volute and the bellows satisfy the following relationship: Wherein: N1 is the distance between the farthest right end of the profile corresponding to the volute and the center of the impeller; α2 is the angle between the line connecting the farthest right end of the profile corresponding to the volute and the center of the impeller and the positive direction of the X-axis; L is the width of the inner flow channel of the bellows; N2 is the distance between the farthest left end of the profile corresponding to the volute and the center of the impeller; α4 is the angle between the line connecting the farthest left end of the profile corresponding to the volute and the center of the impeller and the negative direction of the X-axis; s1 is the total value of the gap between the left and right sides of the volute and the bellows. The total gap between the volute and the left and right sides of the bellows is between 0 mm and 40 mm.

7. The centrifugal fan according to any one of claims 1 to 3, characterized in that, The volute and the bellows satisfy the following relationship: Where: M2 is the distance between the farthest point of the upper end of the profile corresponding to the volute and the center of the impeller; k2 is the second distance coefficient; α0 is the volute tongue clearance coefficient; and D is the diameter of the impeller.

8. The centrifugal fan according to claim 7, characterized in that, The cochlear tongue gap coefficient is between 0.05 and 0.1; the second distance coefficient is between 1.1 and 1.

5. The centrifugal fan also includes an air outlet plate fixed to the top of the air box and connected to the air outlet of the volute; the distance between the farthest point of the upper end of the profile corresponding to the volute and the air outlet plate is between 10mm and 40mm.

9. The centrifugal fan according to any one of claims 1 to 3, characterized in that, The centrifugal fan further includes an air outlet plate fixed to the top of the air box and connected to the air outlet of the volute; the volute and the air box satisfy the following relationship: Where: M1 is the distance between the farthest point of the lower end of the profile corresponding to the volute and the center of the impeller; a3 is the angle between the line connecting the farthest point of the lower end of the profile corresponding to the volute and the center of the impeller and the negative direction of the Y-axis; k3 is the third distance coefficient; H is the height of the inner flow channel of the wind box; m1 is the upper limit of the width-to-height ratio of the inner flow channel of the wind box; L is the width of the inner flow channel of the wind box; s2 is the minimum value among the distances between the farthest point of the lower end of the profile corresponding to the volute and the bottom wall of the wind box and the distance from the position m1L below the air outlet plate; D is the diameter of the impeller; The minimum value of the distance between the farthest point of the lower end of the profile corresponding to the volute and the bottom wall of the wind box and the distance from the m1L position below the air outlet plate is between 20mm and 70mm.

10. The centrifugal fan according to claim 9, characterized in that, The third distance coefficient takes a value between 0.5 and 0.

7.

11. A range hood, characterized in that, include: Centrifugal fan as described in any one of claims 1 to 10; and The smoke collection chamber is located below the centrifugal fan and is connected to the air box of the centrifugal fan.

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