Centrifugal fan and extractor hood

Abstract

The application relates to a centrifugal fan and a range hood. The centrifugal fan comprises: a wind box; a volute arranged in the wind box; and an impeller rotatably arranged in the volute; the impeller and the wind box satisfy the following relationship: wherein D is the diameter of the impeller; pi is the circular constant; the upper limit m1 of the width-height ratio L / H of the inner flow channel of the wind box is 1.05-1.15; the lower limit m0 of the width-height ratio L / H of the inner flow channel of the wind box is 0.85-0.95; and the width of the inner flow channel of the wind box is 380-420 mm.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of range hood, in particular to a centrifugal fan and a range hood. BACKGROUND

[0002] With the improvement of people's living quality, the range hood gradually becomes an indispensable electrical appliance in the kitchen, which is usually installed above the kitchen stove, can suck the oil fume generated in the cooking process, thereby purifying the kitchen environment and improving the comfort of people when cooking.

[0003] The core power system of the existing range hood generally adopts a multi-wing centrifugal fan, that is, the airflow first flows out through the impeller, and then is collected and pressurized by the volute, and is guided to the outdoor, so the design of the fan volute will directly affect the core indicators such as the air volume and the noise of the range hood. In the design of the traditional fan, the inlet and outlet angles and the pressure coefficient of the impeller are selected according to the total flow Q, static pressure P, and speed n of the range hood, and the related parameters such as the diameter and depth of the impeller are further determined, and then the volume and profile of the volute are determined according to the logarithmic spiral formula or the Archimedes spiral formula. If the centrifugal fan is installed in the wind box, it is limited by the size of the flow channel in the wind box, and usually adopts the form of one-side cutting or equal-proportion scaling to meet the size requirements of the flow channel in the wind box.

[0004] However, on the one hand, the ideal impeller size solved by the flow and pressure parameters without space limitation usually cannot well match the use scene of the range hood under the limited wind box, and there is usually the problem of too large impeller, and the volute is not left with sufficient pressure expansion space. On the other hand, the width and height of the flow channel in the range hood are limited by the installation conditions, and the width and height of the flow channel in the wind box may be quite different in different models, and the volute designed based on the traditional spiral line generally has similar length and width in the radial section, so when the fan is put into the wind box defined by the range hood, the volute volume and the wind box may not match; for example, when the volute is too large, the generated volute profile needs to be further processed, such as one-side cutting or overall scaling, to meet the size limitation of the wind box, which may cause performance problems such as reduced efficiency and increased noise. SUMMARY

[0005] In view of the problem that the existing fan impeller is not effectively associated with the size of the wind box in the limited space when designed based on the pressure and flow parameters, resulting in the mismatch between the impeller volume and the size of the wind box, the present application provides a centrifugal fan and a range hood, which can establish the association between the impeller diameter and the size of the wind box, fully utilize the wind box space to design a reasonable impeller volume, solve the mismatch between the two, and realize the optimal design of aerodynamic performance and noise.

[0006] According to one aspect of the present application, the present application provides a centrifugal fan, comprising: a wind box; a volute arranged in the wind box; and an impeller rotatably arranged in the volute; the impeller and the wind box satisfy the following relationship:

[0007] ; wherein D is the diameter of the impeller; k0 is a proportionality coefficient; L is the inner flow passage width of the wind box; H is the inner flow passage height of the wind box; π is the circular constant; m0 and m1 are the lower limit and the upper limit of the inner flow passage width-height ratio of the wind box, respectively.

[0008] In one embodiment of the present application, the upper limit of the inner flow passage width-height ratio of the wind box is between 1.05 and 1.15; the lower limit of the inner flow passage width-height ratio of the wind box is between 0.85 and 0.95.

[0009] In one embodiment of the present application, the inner flow passage width of the wind box is between 380 mm and 420 mm.

[0010] In one embodiment of the present application, the proportionality coefficient is between 0.25 and 0.4.

[0011] In one embodiment of the present application, the angle between the line connecting the uppermost point of the profile line corresponding to the volute and the center of the impeller and the positive direction of the Y-axis is between -10° and 20°; the angle between the line connecting the rightmost point of the profile line corresponding to the volute and the center of the impeller and the positive direction of the X-axis is between -25° and 30°; the angle between the line connecting the lowermost point of the profile line corresponding to the volute and the center of the impeller and the negative direction of the Y-axis is between -25° and 45°; the angle between the line connecting the leftmost point of the profile line corresponding to the volute and the center of the impeller and the negative direction of the X-axis is between -20° and 30°.

[0012] In one embodiment of the present application, the volute and the wind box satisfy the following relationship:

[0013] ; wherein: N2 is the distance between the leftmost point of the profile line corresponding to the volute and the center of the impeller; ɑ4 is the angle between the leftmost point of the profile line corresponding to the volute and the center of the impeller and the negative direction of the X-axis; k1 is a first distance coefficient; L is the inner flow passage width of the wind box; m1 is the upper limit of the inner flow passage width-height ratio of the wind box; H is the inner flow passage height of the wind box; D is the diameter of the impeller; s1 is the total value of the left and right side gaps between the volute and the wind box.

[0014] In one embodiment of the present application, the total value of the left and right side gaps between the volute and the wind box is between 0 mm and 40 mm; the first distance coefficient is between 0.65 and 0.8.

[0015] In an embodiment of the present application, the volute and the wind box satisfy the relationship:

[0016] ; wherein: N1 is the distance between the farthest point on the right end of the profile line corresponding to the volute and the center of the impeller; a2 is the included angle between the line connecting the farthest point on the right end of the profile line 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 passage of the wind box; N2 is the distance between the farthest point on the left end of the profile line corresponding to the volute and the center of the impeller; a4 is the included angle between the line connecting the farthest point on the left end of the profile line 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 left and right side gaps between the volute and the wind box.

[0017] In an embodiment of the present application, the volute and the wind box satisfy the relationship: ; wherein: M2 is the distance between the farthest point on the upper end of the profile line corresponding to the volute and the center of the impeller; k2 is the second distance coefficient; a0 is the volute tongue gap coefficient of the volute; D is the diameter of the impeller.

[0018] In an embodiment of the present application, the volute tongue gap coefficient is valued between 0.05 and 0.1; and the second distance coefficient is valued between 1.1 and 1.5.

[0019] In an embodiment of the present application, the centrifugal fan further comprises an air outlet plate fixed on the top of the wind box and connected with the air outlet of the volute; the distance between the farthest point on the upper end of the profile line corresponding to the volute and the air outlet plate is valued between 10 mm and 40 mm.

[0020] In an embodiment of the present application, the centrifugal fan further comprises an air outlet plate fixed on the top of the wind box and connected with the air outlet of the volute; the volute and the wind box satisfy the relationship:

[0021] ; wherein: M1 is the distance between the farthest point on the lower end of the profile line corresponding to the volute and the center of the impeller; a3 is the included angle between the line connecting the farthest point on the lower end of the profile line 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 passage of the wind box; m1 is the upper limit of the width-height ratio of the inner flow passage of the wind box; L is the width of the inner flow passage of the wind box; s2 is the minimum value of the distances between the farthest point on the lower end of the profile line corresponding to the volute and the bottom wall of the wind box and the position m1L below the air outlet plate, respectively; D is the diameter of the impeller.

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

[0023] According to another aspect of the present application, an embodiment of the present application provides a range hood, comprising: any one of the above centrifugal fan; and a smoke collecting cavity located below the centrifugal fan and in communication with the wind box of the centrifugal fan.

[0024] In summary, the centrifugal fan of the present application can reasonably limit the impeller volume based on the size of the wind box by establishing a relationship between the size of the impeller and the size of the wind box, to solve the problem of mismatch between the two, and to achieve optimal design of aerodynamic performance and noise. At the same time, the centrifugal fan of the present application also sets a range of width-height ratio of the inner flow passage. When the width-height ratio exceeds the range, the impeller volume will be considered in the direction of the smaller side, otherwise the volute opening in one direction will be limited, affecting the overall diffuser effect, and easily causing vortex inside the volute.

[0025] In addition, the volute based on the traditional spiral line design will also have the problem of mismatch between the volute volume and the wind box when placed in the inner flow passage of the wind box, such as the size of the volute radial section in one direction being appropriate, while the size in the other direction exceeding the wind box, which requires partial profile cutting or overall scaling, which will cause damage to the aerodynamic performance of the fan, or there is still a lot of space in a certain direction that is not utilized, and the performance potential cannot be fully utilized. The centrifugal fan of the present application can establish a design relationship based on the size of the inner flow passage of the wind box and the size of the impeller to select the characteristic position of the volute radial section in multiple directions to solve the problem of mismatch between the opening of the volute in each direction and the inner flow passage of the wind box, and to achieve optimal design of aerodynamic performance and noise. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A flowchart of the design method of the centrifugal fan according to an embodiment of the present application is shown;

[0027] Figure 2 A flowchart of the volute design step in the design method of the centrifugal fan according to the above embodiment of the present application is shown;

[0028] Figure 3 A perspective view of the range hood according to an embodiment of the present application is shown;

[0029] Figure 4 A cross-sectional view of the range hood according to the above embodiment of the present application is shown;

[0030] Figure 5Fig. 1 shows a structural schematic diagram of a centrifugal fan in a range hood according to the above embodiment of the present application;

[0031] Figure 6 Fig. 2 shows a state schematic diagram of a down-shifted volute in a range hood according to the above embodiment of the present application.

[0032] Main element symbol explanation:

[0033] 10, centrifugal fan; 11, air bellow; 12, volute; 13, impeller; 14, air outlet plate; 20, smoke collecting cavity.

[0034] The above main element symbol explanation further details the present application in combination with the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0035] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application are described in detail below in combination with the accompanying drawings. In the following description, a lot of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, and therefore the present application is not limited to the specific embodiments disclosed below.

[0036] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0037] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features referred to. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0038] In the present application, unless specifically defined and limited otherwise, the terms "mounting", "connected", "connection", "fixed", and the like, should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements, unless specifically defined otherwise. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] In the present application, unless specifically defined and limited otherwise, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be the first feature directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "below", "below" and "below" the second feature can be the first feature directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0040] It should be noted that when an element is referred to as "fixed to" or "provided on" another element, it can be directly on another element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to another element or a middle element can exist at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only embodiment.

[0041] Considering that the size of the impeller designed based on the performance parameters cannot effectively match the inner flow passage space of the wind box, and most of the range hood fan system is placed in the wind box, the size of the wind box is limited by the user installation scene, which is the main influence on the size of the impeller, resulting in that the ideal impeller size solved based on flow and pressure parameters without space limitation usually does not match, and then the volute profile needs to be excessively compressed to meet the installation requirements, causing performance problems such as reduced efficiency and increased noise. Therefore, in order to solve this problem, the present application provides a centrifugal fan and a design method and a range hood, which can establish the correlation between the impeller diameter and the size of the wind box, fully utilize the wind box space to design a reasonable impeller volume, solve the mismatching problem, and realize the optimal design of aerodynamic performance and noise.

[0042] Specifically, as shown in Figure 1 An embodiment of the present application provides a design method of a centrifugal fan, which can include the steps of:

[0043] S100: correlation between impeller diameter and size of the wind box is established to obtain an impeller-wind box relationship model;

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

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

[0046] More specifically, the impeller-wind box relationship model is ; wherein D is the impeller diameter; k0 is the proportional coefficient; L is the width of the inner flow passage of the wind box; H is the height of the inner flow passage of the wind box; π is the circular constant; m0 and m1 are the lower limit and upper limit of the width-height ratio of the inner flow passage of the wind box, respectively.

[0047] It is worth noting that the size of the impeller in the wind box is too large or too small, which is not conducive, such as less than the limit value, the impeller is small, although the volute opening can be increased to reduce the flow rate in the volute, but the airflow cannot effectively fill the entire volute space, and the flow non-uniformity is even more serious; and greater than the limit value, the impeller is large, and the volute opening is limited, which cannot effectively convert the outlet flow pressure of the impeller into static pressure, resulting in serious energy loss. Since in the use scene of the range hood, the speed, flow and pressure of the range hood are variable, selecting a parameter to design the impeller can only represent a certain working condition, and in actual design, the increase of the impeller volume is beneficial to the improvement of noise control and starting performance; therefore, the design method of the centrifugal fan of the present application first establishes the relationship between the size of the impeller and the size of the wind box, and then obtains the optimal impeller size parameter through the size of the wind box, which can reasonably design the impeller volume based on the size of the wind box, solve the problem of mismatch between the two, and realize the optimal design of aerodynamic performance and noise.

[0048] In addition, the design method of the centrifugal fan of the present application also sets the interval range of the width-height ratio of the inner flow passage, when the width-height ratio exceeds the range, the impeller volume will be considered in the direction of the smaller side, otherwise the volute opening in a certain direction will be limited, affecting the overall pressure expansion effect, and easily causing vortex in the volute.

[0049] Optionally, the upper and lower limits of the inner flow passage width-height ratio of the wind box satisfy: 0.85≤m0≤0.95, 1.05≤m1≤1.15; that is, the upper limit m1 of the inner flow passage width-height ratio of the wind box is valued between 1.05 and 1.15; the lower limit m0 of the inner flow passage width-height ratio of the wind box is valued between 0.85 and 0.95. Preferably, m0=0.9; m1=1.1. It can be understood that the upper and lower limit intervals of the inner flow passage width-height ratio mentioned in the present application are set with reference to the ratio of the conventional volute in the width and height directions; when the width-height ratio exceeds this interval, the impeller diameter cannot be constrained in two dimensions at the same time, because it is easy to cause the impeller diameter to be too large, causing the size of the volute in the smaller dimension to be limited.

[0050] Optionally, the proportionality coefficient k0 mentioned in the present application satisfies: 0.25≤k0≤0.4; that is, the proportionality coefficient k0 is valued between 0.25 and 0.4, so as to control the noise while avoiding the limitation of the volute opening, facilitating the reduction of pressure loss. It can be understood that when the proportionality coefficient k0 is less than 0.25, the impeller volume is small relative to the size of the wind box, the outflow velocity of the impeller is fast under the same air volume, which is not conducive to controlling the noise; when the proportionality coefficient k0 is greater than 0.4, the space left for the volute is limited, causing the volute opening to be limited, which cannot effectively convert the outflow dynamic pressure of the impeller into static pressure, causing serious pressure loss.

[0051] It is worth noting that the volute based on the traditional spiral line design will also have the problem of mismatch between the volute volume and the wind box when placed in the inner flow passage of the wind box, such as the size of the volute radial section in one direction being appropriate, while the size in the other direction exceeding the wind box, which requires local profile cutting or overall scaling, which will cause the aerodynamic performance of the fan to be damaged, or there is still a lot of space in a certain direction that is not utilized, and the performance potential cannot be fully utilized. In order to solve this problem, the design method of the centrifugal fan of the present application can select the characteristic positions of the volute radial section in multiple directions based on the size of the wind box inner flow passage and the size of the impeller to establish a design relationship, so as to solve the problem of mismatch between the volute opening in each direction and the wind box inner flow passage, and realize the optimal design of aerodynamic performance and noise.

[0052] Specifically, as shown in Figure 2 and Figure 5 the step S300 in the design method of the centrifugal fan of the present application can include the steps of:

[0053] S310: establishing a reference coordinate system O-XY based on the radial section of the volute, wherein the origin O coincides with the center of the impeller, the X-axis is perpendicular to the height direction of the wind box and takes the direction away from the outlet of the volute as the positive direction, and the Y-axis is parallel to the height direction of the wind box and takes the direction close to the outlet of the volute as the positive direction;

[0054] S320: Select the two farthest points of each point on the volute profile projected on the X-axis and Y-axis to obtain the uppermost point P1, the rightmost point P2, the lowermost point P3 and the leftmost point P4 of the volute profile;

[0055] S330: Construct the correlation between each farthest point on the volute profile and the impeller center to obtain the uppermost point distance model, the rightmost point distance model, the lowermost point distance model and the leftmost point distance model;

[0056] S340: Based on the inner flow passage width and the inner flow passage height of the wind box and the impeller diameter obtained, the size of the volute profile in the width direction and the height direction is solved through the multiple farthest point distance models.

[0057] It is worth noting that, as shown in Figure 5 , although the uppermost point P1, the rightmost point P2, the lowermost point P3 and the leftmost point P4 of the volute profile are not necessarily on the X-axis or Y-axis, in order to avoid serious flow channel mutation, the angle a1 between the line connecting the uppermost point P1 and the impeller center and the positive direction of the Y-axis is preferably between -10° and 20°; the angle a2 between the line connecting the rightmost point P2 and the impeller center and the positive direction of the X-axis is preferably between -25° and 30°; the angle a3 between the line connecting the lowermost point P3 and the impeller center and the negative direction of the Y-axis is preferably between -25° and 45°; the angle a4 between the line connecting the leftmost point P4 and the impeller center and the negative direction of the X-axis is preferably between -20° and 30°. It can be understood that the angles mentioned in the present application are positive angles in the clockwise direction and negative angles in the counterclockwise direction; for example, as shown in Figure 5 , the angles a1, a2, a3 and a4 are all positive angles.

[0058] In addition, within the limited wind box, after the impeller diameter is determined, the remaining space is the volute space, and then the size of the volute profile in the width direction and the height direction is designed according to the remaining space, wherein as shown in Figure 5 , the size of the volute profile in the width direction includes the distance N2 between the rightmost point P2 of the volute profile and the impeller center and the distance N2 between the leftmost point P4 of the volute profile and the impeller center; the size of the volute profile in the height direction includes the distance M1 between the lowermost point P3 of the volute profile and the impeller center, the distance M2 between the uppermost point P1 of the volute profile and the impeller center, and the distance M3 between the uppermost point P1 of the volute profile and the outlet plate of the centrifugal fan.

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

[0060] Exemplarily, in one example of the present application, the left end farthest point distance model can be but is not limited to being implemented as: ;

[0061] wherein: N2 is the distance between the left end farthest point P4 of the volute profile and the center of the impeller; a4 is the included angle between the left end farthest point P4 and the center of the impeller and the negative direction of the X axis; k1 is the first distance coefficient; L is the width of the inner flow passage of the wind box; m1 is the upper limit of the width-height ratio of the inner flow passage of the wind box; H is the height of the inner flow passage of the wind box; D is the diameter of the impeller; s1 is the total value of the left and right side gaps between the volute and the wind box. It can be understood that the min mentioned in the present application refers to the minimum value, for example, min (L, m1H) refers to the minimum value between the product m1H of the upper limit of the width-height ratio of the inner flow passage of the wind box and the height of the inner flow passage of the wind box and the width L of the inner flow passage of the wind box.

[0062] It is worth noting that, although the distance N2 between the left end farthest point P4 and the center of the impeller is in the width direction of the volute profile, when the size of the wind box in a certain direction is larger than that in another direction, it is not appropriate to only consider the size limitation of the wind box in a single direction; and the left end farthest point distance model of the present application simultaneously considers the size limitations in two directions (including the width direction and the height direction) by using min (L, m1H), which can improve the final diffusing effect of the volute and avoid causing local high-speed areas of the airflow.

[0063] In addition, the total value s1 of the left and right side gaps between the volute and the wind box refers to the sum of the horizontal distance between the left end farthest point P4 of the volute profile and the left wall of the wind box and the horizontal distance between the right end farthest point P2 of the volute profile and the right wall of the wind box. Preferably, the total value s1 of the left and right side gaps between the volute and the wind box is valued between 0 mm and 40 mm. It can be understood that, if the wind box is provided with noise reduction material, the total value s1 of the left and right side gaps between the volute and the wind box is generally the maximum value.

[0064] Optionally, the first distance coefficient k1 is between 0.65 and 0.8, so as to reasonably balance the distance N2 between the left end farthest point P4 of the volute profile and the center of the impeller and the distance N1 between the right end farthest point P2 of the volute profile and the center of the impeller. It can be understood that when the first distance coefficient k1 is less than 0.65, the distance N2 between the left end farthest point P4 of the volute profile and the center of the impeller will be too small to affect the final diffusing effect of the volute; when the first distance coefficient k1 is greater than 0.8, the distance N1 between the right end farthest point P2 of the volute profile and the center of the impeller will be too small to easily cause a local high-speed area of the airflow, which is not conducive to noise control.

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

[0066] wherein N1 is the distance between the right end farthest point P2 of the volute profile and the center of the impeller; a2 is the included angle between the line between the right end farthest point P2 and the center of the impeller and the positive direction of the X axis; L is the width of the inner flow passage of the wind box; N2 is the distance between the left end farthest point P4 of the volute profile and the center of the impeller; a4 is the included angle between the line between the left end farthest point P4 and the center of the impeller and the negative direction of the X axis; and s1 is the total value of the gaps between the volute and the two sides of the wind box.

[0067] It is worth noting that although the size of the volute profile in the height direction is composed of three sections (M1, M2 and M3), the distance M2 between the upper end farthest point P1 of the volute profile and the center of the impeller is located near the volute tongue position, so this position is a key position affecting noise. Therefore, the design method of the centrifugal fan of the present application preferably considers the size design at this position according to the volute tongue gap t, wherein the volute tongue gap t can be determined according to the empirical formula t = a0D, wherein 0.05 ≤ a0 ≤ 0.1.

[0068] Specifically, the upper end farthest point distance model can be implemented as: ;

[0069] wherein M2 is the distance between the upper end farthest point P1 of the volute profile and the center of the impeller; k2 is a second distance coefficient; a0 is a volute tongue gap coefficient; and D is the diameter of the impeller.

[0070] Preferably, the second distance coefficient k2 is between 1.1 and 1.5, so that the upper end farthest point P1 near the volute tongue position of the volute profile is controlled within a reasonable range of increase, so as to prevent the airflow after being divided through the volute tongue from flowing back into the volute while reducing noise. It can be understood that when the second distance coefficient k2 is greater than 1.5, the airflow after being divided through the volute tongue is easy to flow back into the volute, affecting the efficiency of the fan; when the second distance coefficient k2 is less than 1.1, there will be a relatively long narrow passage near the volute tongue position of the volute profile, resulting in a large turbulence intensity and causing noise to increase.

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

[0072] wherein: M1 is the distance between the lower end farthest point P3 of the volute profile and the center of the impeller; a3 is the included angle between the line connecting the lower end farthest point P3 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 passage of the wind box; m1 is the upper limit of the width-height ratio of the inner flow passage of the wind box; L is the width of the inner flow passage of the wind box; s2 is the minimum value of the distance between the lower end farthest point P3 of the volute profile and the bottom wall of the wind box and the position m1L below the outlet plate; and D is the diameter of the impeller. It can be understood that the min mentioned in the present application means to take the minimum value, for example, min(H, m1L) means the minimum value of the product m1L of the upper limit of the width-height ratio of the inner flow passage of the wind box and the width of the inner flow passage of the wind box and the height H of the inner flow passage of the wind box.

[0073] It is worth noting that the distance M1 between the lower end farthest point P3 of the volute profile and the center of the impeller is usually large, and the size limitation of the wind box needs to be considered; and in the case that the size of the wind box in one direction is larger than that in another direction, it is not appropriate to only consider the size limitation of the wind box in one direction. Therefore, the lower end farthest point distance model of the present application considers the size limitation in both directions (including the height direction and the width direction) by using min(H, m1L), which can reduce the influence of vortex and backflow and improve the performance of the fan.

[0074] Further, the minimum value s2 of the distance between the lower end farthest point P3 of the volute profile and the bottom wall of the wind box and the position m1L below the outlet plate means the minimum value of the vertical distance between the lower end farthest point P3 of the volute profile and the bottom wall of the wind box and the vertical distance between the lower end farthest point P3 of the volute profile and the position m1L below the outlet plate. Preferably, the minimum value s2 of the distance between the lower end farthest point P3 of the volute profile and the bottom wall of the wind box and the position m1L below the outlet plate is between 20 mm and 70 mm, so as to keep a certain distance from the lower inlet or for the arrangement of noise reduction materials.

[0075] Preferably, the third distance coefficient k3 is in the range of 0.5 to 0.7, so that the lower end farthest point P3 of the volute profile is controlled within a reasonable reduced proportion, so as to prevent the self-flow direction profile from changing too fast in curvature, reduce the risk of vortex, so as to leave enough space for the distance M3 between the upper end farthest point P1 of the volute profile and the outlet plate of the fan. It can be understood that when the third distance coefficient k3 is less than 0.5, the bottom opening degree of the part of the volute profile corresponding to the lower end farthest point P3 as the main flow inlet area of the fan will be seriously insufficient and affect the performance of the fan; when the third distance coefficient k3 is greater than 0.7, the opening degree of the bottom area of the volute will be expanded more than other parts, the self-flow direction profile changes too fast in curvature, and vortex is easily generated, and the distance M3 between the upper end farthest point P1 of the volute profile and the outlet plate of the centrifugal fan is limited, which seriously affects the outlet section flow conversion efficiency.

[0076] It is worth noting that the distance M3 between the upper end farthest point P1 of the volute profile and the outlet plate of the centrifugal fan corresponds to the extension height of the volute outlet section, and the length of this section will affect the outlet section flow conversion efficiency; 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 is easy to cause backflow; if the distance M3 is too long, it will affect the design of the main body profile of the volute under the condition that the height of the volute is limited. Preferably, the distance M3 between the upper end farthest point P1 of the volute profile and the outlet plate of the centrifugal fan is in the range of 10mm to 40mm.

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

[0078] Specifically, as shown in Figures 4 to 6 , the centrifugal fan 10 can include a wind box 11, a volute 12 arranged in the wind box 11, and an impeller 13 rotatably arranged in the volute 12.

[0079] More specifically, as shown in Figures 4 to 6 , the impeller 13 and the wind box 11 satisfy the relationship: ; wherein D is the diameter of the impeller 13; k0 is a proportion coefficient; L is the inner flow passage width of the wind box 11; H is the inner flow passage height of the wind box 11; π is the circular constant; m0 and m1 are the lower limit and the upper limit of the width-height ratio of the inner flow passage of the wind box 11, respectively.

[0080] Optionally, as shown in Figure 4 , the centrifugal fan 10 further includes an outlet plate 14 fixedly arranged at the top of the wind box 11 and connected with the outlet of the volute 12.

[0081] It is worth noting that the inner channel width L mentioned in the present application refers to the distance between the left and right inner surfaces of the air baffle 11 when facing the direction of the air inlet of the fan, as shown in Figure 4 Alternatively, the inner channel width L of the air baffle 11 is between 380mm and 420mm. It can be understood that, as the range hood tends to be lighter, thinner and smaller in design to meet the needs of kitchen space coordination and aesthetics: when the inner channel width L exceeds 420mm, although the diameter of the impeller 13 can be increased to improve the performance of the fan, the overall size of the fan structure is correspondingly increased, which may cause installation difficulties or even failure in the case of limited installation space or embedded cabinet. Conversely, when the inner channel width L is less than 380mm, although the installation space is limited, the diameter of the impeller 13 is limited, which will cause a significant decrease in the performance of the fan, thereby affecting the oil fume extraction effect.

[0082] In addition, the inner channel height H mentioned in the present application refers to the clear flow channel height provided by the range hood, specifically the distance between the top plane and the limit lower plane parallel to the top plane, wherein the top plane usually refers to the plane where the air outlet plate 14 is located; the limit lower plane usually refers to the lowest point of the volute 12 when the volute 12 is moved downward in the original posture and first comes into rigid contact with any other component (such as the smoke collecting cavity 20) of the range hood, as shown in Figure 6 It can be understood that, for the lifting type range hood, the inner channel height H mentioned in the present application is the distance between the top plane and the limit lower plane when the range hood is in a non-working state.

[0083] Alternatively, the upper limit m1 of the width-height ratio of the inner channel of the air baffle 11 is between 1.05 and 1.15; and the lower limit m0 of the width-height ratio of the inner channel of the air baffle 11 is between 0.85 and 0.95.

[0084] Alternatively, the proportion coefficient k0 is between 0.25 and 0.4.

[0085] Alternatively, as shown in Figure 5 The angle a1 between the line connecting the uppermost point P1 of the corresponding profile of 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 a2 between the line connecting the rightmost point P2 of the corresponding profile of 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 a3 between the line connecting the lowermost point P3 of the corresponding profile of 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 a4 between the line connecting the leftmost point P4 of the corresponding profile of 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 an example of the present application, as shown inFigures 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: ; wherein: M1 is the distance between the lowermost point P3 of the corresponding profile line of the volute 12 and the center of the impeller 13; ɑ3 is the included angle between the line connecting the lowermost point P3 of the corresponding profile line of the volute 12 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 passage of the wind box 11; m1 is the upper limit of the width-height ratio of the inner flow passage of the wind box 11; L is the width of the inner flow passage of the wind box 11; s2 is the minimum value of the distance between the lowermost point P3 of the corresponding profile line of the volute 12 and the bottom wall of the wind box 11 and the position m1L below the air outlet plate 14; and D is the diameter of the impeller 13.

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

[0094] It is worth mentioning that, in another embodiment of the present application, as shown in Figures 3 to 6 the present application further provides a range hood, which can include the above-mentioned centrifugal fan 10 and a smoke collecting cavity 20 located below the centrifugal fan 10 and in communication with the wind box 11 of the centrifugal fan 10. It can be understood that the range hood of the present application can also include, but is not limited to, a control panel, a water tank or a water receiving box to assist in completing the oil fume extraction function, which will not be described here.

[0095] In addition, the range hood of the present application can further include a control box communicatively connected with the centrifugal fan 10, which can be controlled by a voice module, and the control box is installed with a controller, a voice receiving module and a voice analysis module. The voice receiving module receives the instructions of the user, and the voice analysis module analyzes the instructions. According to the analyzed instructions, the controller controls the range hood to perform corresponding operations, so as to realize the intelligent regulation and control of the range hood and improve the user's experience.

[0096] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0097] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present 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: Wherein: 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 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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