Centrifugal fan casing, centrifugal fan, range hood and range hood control method

Abstract

This invention relates to a centrifugal fan casing, a centrifugal fan, a range hood, and a range hood control method. The centrifugal fan casing includes: a front cover plate with an inlet; a rear cover plate; and an annular wall disposed between the front and rear cover plates. It is characterized by further including: an atomizer disposed at the inlet, having multiple through holes for airflow and multiple nozzles for ejecting charged gas particles into the inner cavity of the casing; and an airflow adjustment assembly including an airflow adjustment unit disposed on the outer surface of the front cover plate. The airflow adjustment unit includes a magnetic field band and an airflow detection band. The airflow adjustment assembly is configured to: control the magnetic field band to generate a corresponding magnetic field based on the airflow detected by the airflow detection band, and utilize the magnetic field to coordinate with the charged gas particles to adjust the airflow. The advantages are: it can achieve real-time optimization and adjustment of the airflow direction under different fume conditions, making the airflow in the casing smoother and improving the fan performance.

Description

Technical Field

[0001] This invention relates to the field of fan technology, and in particular to a volute for a centrifugal fan, a centrifugal fan, a range hood, and a control method for a range hood. Background Technology

[0002] A range hood is a kitchen appliance designed to purify the kitchen environment. It works on the principle of fluid dynamics, using a centrifugal fan installed inside to draw in and exhaust cooking fumes. The centrifugal fan consists of a casing, an impeller housed within the casing, and a motor that drives the impeller. As the impeller rotates, a negative pressure is generated at the center of the fan, drawing in the cooking fumes from below. After being accelerated by the fan, the fumes are collected by the casing and guided outwards, thus purifying the kitchen environment. As the core component of the range hood, the fan system's performance significantly impacts its effectiveness.

[0003] Currently, most centrifugal fans on the market have a spiral volute profile. This type of centrifugal fan features large air volume and low noise. However, spiral centrifugal fans are designed and tested for non-oil fume environments. Since the properties of oil fume gas in users' homes are different from ordinary air, the performance of the spiral centrifugal fan's volute deteriorates during use, preventing it from achieving its ideal performance. Furthermore, because oil fume particles are heavier and more viscous than air particles, they have stronger inertia. This causes the oil fume particles to fail to turn in time during cooking, constantly colliding with the volute ring wall, greatly reducing the fan's performance and limiting its operating conditions.

[0004] To address the aforementioned technical problems, Chinese invention patent ZL201910871490.5 (application publication number CN110608194B) discloses a centrifugal fan steering volute. This volute includes a collecting section and a steering section. The collecting section is formed by an annular wall surface, a front helical surface, and a rear helical surface. The lower edge and upper edge of the annular wall surface are designed according to a profile. Both the front and rear helical surfaces are perpendicular to the annular wall surface and are connected to its lower and upper edges, respectively. The steering section is an elbow-shaped flow channel formed by a large arc surface, a small arc surface, an annular wall side plane, and a volute tongue side plane. The large arc surface, small arc surface, and annular wall side plane are tangent to the ends of the front helical surface, rear helical surface, and annular wall surface, respectively. The volute tongue side plane connects the large arc surface and the small arc surface and is parallel to the annular wall side plane. Although this volute can achieve airflow deflection in a specific direction within the volute by integrating the deflecting section into the volute and using an integrated curvature design for the collection and deflecting sections, resulting in a compact structure, small size, and minimal flow loss, the aforementioned volute has the following limitations: Since the volute guides airflow by altering its structure, different fume conditions during the operation of the range hood will cause the airflow to exhibit different flow patterns, rather than a fixed flow path. Therefore, the aforementioned airflow adjustment effect is ineffective. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a centrifugal fan casing that can adjust the airflow direction in real time according to different oil fume conditions to improve the fan effect, in contrast to the above-mentioned prior art.

[0006] The second technical problem to be solved by the present invention is to provide a centrifugal fan using the above-mentioned volute.

[0007] The third technical problem to be solved by the present invention is to provide a range hood that uses the above-mentioned centrifugal fan.

[0008] The fourth technical problem to be solved by the present invention is to provide a control method for the above-mentioned range hood.

[0009] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a volute casing for a centrifugal fan, comprising:

[0010] The front cover has an air inlet that extends through its wall thickness;

[0011] The rear cover plate is disposed at a distance from the front cover plate;

[0012] The annular wall is located between the front cover plate and the rear cover plate, and the annular wall, the front cover plate and the rear cover plate together limit the inner cavity of the volute and the air outlet located at the top.

[0013] Its features also include:

[0014] An atomizer is provided at the front air inlet. The atomizer has multiple through holes for airflow and multiple nozzles that can spray charged gas particles toward the inner cavity of the volute.

[0015] An airflow adjustment assembly includes an airflow adjustment unit disposed on the outer surface of the front cover plate. The airflow adjustment unit includes a magnetic field band for forming a magnetic field and an airflow detection band for detecting airflow. The airflow adjustment assembly is configured to: control the magnetic field band to generate a corresponding magnetic field based on the airflow result detected by the airflow detection band, and use the magnetic field to cooperate with charged gas particles to adjust the airflow.

[0016] To ensure smoother airflow within the volute, preferably, the airflow adjustment unit on the outer surface of the front cover is two: an inner airflow adjustment unit and an outer airflow adjustment unit located around the inner airflow adjustment unit. The inner airflow adjustment unit is arranged around at least a portion of the outer periphery of the front cover adjacent to the forward air inlet, and the outer airflow adjustment unit is arranged around at least a portion of the outer periphery of the front cover adjacent to its outer edge.

[0017] Preferably, the centrifugal fan includes an impeller disposed within a volute, and the profile of the volute includes a first straight line segment, a spiral line segment, a volute tongue line segment, and a second straight line segment that are sequentially arranged and smoothly connected in the circumferential direction. The starting point of the first straight line segment and the ending point of the second straight line segment correspond to the two ends of the air outlet of the volute, respectively.

[0018] In order to make the initial adjustment of the airflow, preferably, the center of rotation of the impeller is taken as the origin of the coordinate system, and the horizontal line passing through the origin is taken as the X-axis. The magnetic field zone of the internal airflow adjustment unit is denoted as the internal magnetic field zone. The internal magnetic field zone is annular and has a width of d1. The starting point of the internal magnetic field zone is located on the X-axis near the end point of the spiral segment, and the end point of the internal magnetic field zone is located on the line connecting the end point of the first straight line segment and the center of rotation of the impeller.

[0019] Preferably, the closest distance between the internal magnetic field belt and the impeller is d4, d4 = d5 * g1, where d5 is the shortest distance between the impeller and the volute tongue segment, g1 is a first preset value, and the value range of g1 is: 1.5 ≤ g1 ≤ 2.

[0020] In order to make a second adjustment to the airflow, the magnetic field zone of the external airflow adjustment unit is referred to as the external magnetic field zone. The external magnetic field zone is annular and has a width of d2. The starting point of the external magnetic field zone starts from the opening A1 of the spiral line segment, and the end of the external magnetic field zone is located on the horizontal line of the lowest tangent point of the first straight line segment and the volute tongue-shaped line segment.

[0021] Preferably, the value of A1 is: A1 = A3 * g2, where A3 is the maximum opening of the spiral segment, g2 is a second preset value, and 1 / 3 ≤ g2 ≤ 1 / 2.

[0022] Preferably, the distance between the outer side of the external magnetic field band and the volute profile is d3, where d3 = A1 * g3, g3 is a third preset value, and the range of g3 is 0.1 ≤ g3 ≤ 0.3.

[0023] In order to achieve real-time adjustment of airflow within the volute and enhance precise control of airflow within the volute, the airflow detection strip of the inner airflow adjustment unit is set against the outer side of the inner magnetic field strip and is in the same direction of extension of the inner magnetic field strip; and / or the airflow detection strip of the outer airflow adjustment unit is set against the outer side of the outer magnetic field strip and is in the same direction of extension of the outer magnetic field strip.

[0024] Furthermore, the aforementioned airflow adjustment unit is also provided on the outer surface of the rear cover.

[0025] To minimize disruption to the flow of cooking fumes, the atomizer includes a cross-shaped support rod, the end of which is constrained to the front cover plate. The nozzles are multiple and spaced apart on the support rod.

[0026] Preferably, the atomizer further includes a plurality of rings arranged sequentially at intervals between the inner and outer rings, each ring being constrained on the support rod and arranged concentrically with the support rod, and each ring and the support rod together defining the aforementioned through hole.

[0027] The technical solution adopted by the present invention to solve the second technical problem mentioned above is: a centrifugal fan, characterized in that: it includes a centrifugal fan volute as described above.

[0028] The technical solution adopted by the present invention to solve the third technical problem mentioned above is: a range hood, characterized in that: it includes the centrifugal fan as described above.

[0029] The technical solution adopted by the present invention to solve the fourth technical problem mentioned above is: a control method for a range hood as described above, characterized by comprising the following steps:

[0030] Step 1: Start the centrifugal fan and set the initial value of the airflow adjustment number w to 1;

[0031] Step 2: Obtain the air volume q1 of the centrifugal fan in its current state;

[0032] Step 3: Calculate the required gas-mixture flow rate q2. The formula for calculating q2 is:

[0033]

[0034] Where e1 is the preset average charge per unit of oil fume, and e2 is the charge per unit of mixed gas;

[0035] Step 4: Control the nozzle of the atomizer to spray charged gas particles into the inner cavity of the volute at a flow rate of q2;

[0036] Step 5: Monitor the airflow angle at the airflow detection zone of the inner airflow adjustment unit and the airflow angle at the airflow detection zone of the outer airflow adjustment unit respectively, and calculate the inner flow coefficient m1 based on the airflow angle at the airflow detection zone of the inner airflow adjustment unit and the outer flow coefficient m2 based on the airflow angle at the airflow detection zone of the outer airflow adjustment unit.

[0037] Step 6: Determine if the following conditions are met: m1≤M1 and m2≤M2, where M1 is the first preset threshold and M2 is the second preset threshold. If yes, the range hood is operating normally and the process ends; otherwise, proceed to step 7.

[0038] Step 7: Adjust the airflow in the current centrifugal fan for the wth time, and determine whether the current airflow adjustment is successful. If yes, proceed to step 9; otherwise, proceed to step 8.

[0039] Step 8: Determine if w is greater than or equal to W, where W is the preset number of times. If yes, proceed to step 9; otherwise, add 1 to the value of w and update the value of w, increase e1 to k3*e1, where k3 is the preset value and k3>1, and then proceed to step 3 again.

[0040] Step 9: Run the magnetic field bands of the internal airflow adjustment unit and the external airflow adjustment unit according to the magnetic field after the current airflow adjustment.

[0041] Preferably, the formula for calculating m1 is:

[0042]

[0043] Where k1 is the first speed coefficient, r 1i r is the airflow angle monitored at the i-th position in the internal airflow adjustment unit. a This is the preset airflow angle threshold for the internal airflow adjustment unit.

[0044] Preferably, the formula for calculating m2 is:

[0045]

[0046] Where k2 is the second speed coefficient, r 2j r is the airflow angle monitored at the j-th position in the external airflow adjustment unit. b This is the preset airflow angle threshold for the external airflow adjustment unit.

[0047] Preferably, the range of values ​​for k3 in step 8 is: To calculate the Wth root of 2.

[0048] As an improvement, the specific steps for adjusting the airflow in the current centrifugal fan in step 7 are as follows:

[0049] Step 7-1: Set the initial value of the airflow adjustment operation number n1 to 1;

[0050] Step 7-2: Determine if m1 is greater than M1. If yes, proceed to step 7-3; otherwise, proceed to step 7-7.

[0051] Step 7-3: Determine whether the magnetic field adjustment time t1 of the internal airflow adjustment unit is greater than the preset time t2. The preset time t2 is related to the impeller speed fluctuation. If yes, proceed to step 7-6; otherwise, proceed to step 7-4.

[0052] Step 7-4: Calculate and generate the magnetic induction intensity distribution map G1 of the internal magnetic field induction zone based on the airflow angle data of each point on the airflow detection zone of the internal airflow adjustment unit.

[0053] Step 7-5: Activate the magnetic field band of the internal airflow adjustment unit according to the distribution map G1, and proceed to step 7-2;

[0054] Step 7-6: Let t1 = 0;

[0055] Step 7-7: Set the initial value of the external magnetic field adjustment number n3 to 0;

[0056] Step 7-8: Determine if m2 is greater than M2. If yes, proceed to step 7-9; otherwise, proceed to step 7-11.

[0057] Step 7-9: Determine whether the number of external magnetic field adjustments n3 is greater than the first preset threshold n4. If yes, proceed to step 7-13; otherwise, add 1 to the value of n3, update n3, and proceed to step 7-10.

[0058] Steps 7-10: Calculate and generate the magnetic induction intensity distribution map G2 of the external magnetic field induction zone based on the airflow angle data of each point on the airflow detection zone of the external airflow adjustment unit, start the magnetic field zone of the external airflow adjustment unit based on the distribution map G2, and proceed to step 7-8.

[0059] Steps 7-11: Calculate the internal flow coefficient m1 based on the airflow angle at the airflow detection zone of the internal airflow adjustment unit and the external flow coefficient m2 based on the airflow angle at the airflow detection zone of the external airflow adjustment unit.

[0060] Step 7-12: Determine if the following conditions are met: m1≤M1 and m2≤M2. If yes, the adjustment is successful; otherwise, proceed to step 7-13.

[0061] Step 7-13: Determine whether n1 is greater than or equal to the second preset threshold n5. If yes, the adjustment fails; if no, add 1 to the value of n1 and update n1, then proceed to step 7-2.

[0062] Compared with existing technologies, the advantages of this invention are as follows: Charged gas particles are ejected into the inner cavity of the volute via an atomizer. Furthermore, by incorporating an airflow adjustment unit, which includes a magnetic field band for generating a magnetic field and an airflow detection band for detecting airflow, the magnetic field band can be controlled to generate a corresponding magnetic field based on the airflow detection results. The interaction between the magnetic field and the charged gas particles ensures that the Lorentz force on the charged particles always has a positive component in the impeller rotation direction, thus adjusting the airflow. Therefore, this volute can achieve real-time optimization and adjustment of the airflow direction under different oil fume conditions, resulting in smoother airflow within the volute and improved fan performance. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the structure of the range hood in an embodiment of the present invention;

[0064] Figure 2 This is a schematic diagram of the volute structure in an embodiment of the present invention;

[0065] Figure 3 This is a schematic diagram of the volute structure from another perspective in an embodiment of the present invention;

[0066] Figure 4 This is a cross-sectional view of the volute in an embodiment of the present invention;

[0067] Figure 5 This is a partial installation diagram of the magnetic field strip and the airflow detection strip in an embodiment of the present invention;

[0068] Figure 6 for Figure 2 A schematic diagram of the atomizer. Detailed Implementation

[0069] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0070] like Figure 1 As shown, the range hood in this embodiment includes a centrifugal fan. The centrifugal fan in this embodiment includes a volute, an impeller 4 installed inside the volute, and a motor for driving the impeller 4 to rotate.

[0071] like Figures 2-6 As shown, the volute in this embodiment includes a front cover plate 11, a rear cover plate 12, an annular wall 13, an atomizer 2, and an airflow adjustment assembly 3. The front cover plate 11 has a forward air inlet 10a extending through its wall thickness; the rear cover plate 12 is spaced apart from the front cover plate 11; the annular wall 13 is located between the front cover plate 11 and the rear cover plate 12, and the annular wall 13, the front cover plate 11, and the rear cover plate 12 together define the volute cavity 14 and the air outlet 10b located at the top. Figure 4 As shown, the profile of the volute includes a first straight line segment HG, a spiral line segment CG, a volute tongue-shaped line segment BC, and a second straight line segment AB that are arranged and smoothly connected in the circumferential direction. The starting point of the first straight line segment HG and the ending point of the second straight line segment AB correspond to the two ends of the air outlet 10b of the volute 10, respectively.

[0072] The atomizer 2 is located at the front air inlet 10a. The atomizer 2 has multiple through holes 21 for airflow and multiple nozzles 22 that can eject charged gas particles towards the inner cavity 14 of the volute. Figure 6As shown, the atomizer 2 in this embodiment includes a cross-shaped support rod 20 and a plurality of rings 23 arranged sequentially at intervals between the inner and outer sides. The end of the support rod 20 is constrained on the front cover plate 11 (or constrained on the air guide ring at the front air inlet 10a). There are a plurality of nozzles 22, which are spaced apart on the support rod 20. Each ring 23 is constrained on the support rod 20 and arranged concentrically with the support rod 20. Each ring 20 and the support rod 20 together limit the above-mentioned through hole 21.

[0073] The airflow adjustment assembly 3 includes an airflow adjustment unit disposed on the outer surface of the front cover 11. The airflow adjustment unit includes a magnetic field band for forming a magnetic field and an airflow detection band for detecting airflow. The airflow adjustment assembly 3 is configured to: control the magnetic field band to generate a corresponding magnetic field based on the airflow result detected by the airflow detection band, and utilize the magnetic field to cooperate with charged gas particles to adjust the airflow. Figure 2 As shown, in this embodiment, there are two airflow adjustment units on the outer surface of the front cover plate 11: an inner airflow adjustment unit 31 and an outer airflow adjustment unit 32 disposed around the inner airflow adjustment unit 31. The inner airflow adjustment unit 31 is disposed around at least a partial outer periphery of the front cover plate 11 adjacent to the front air inlet 10a, and the outer airflow adjustment unit 32 is disposed around at least a partial outer periphery of the front cover plate 11 adjacent to its outer edge. Of course, as... Figure 3 As shown, the airflow adjustment unit is also provided on the outer surface of the rear cover plate 12, and the installation position of the airflow adjustment unit corresponds one-to-one with the installation position of the airflow adjustment unit on the front cover plate 12.

[0074] like Figure 4 As shown, with the rotation center of impeller 4 as the origin and the horizontal line passing through the origin as the X-axis, the magnetic field zone of the internal airflow adjustment unit 31 is denoted as the internal magnetic field zone 31a. The internal magnetic field zone 31a is annular with a width of d1. The starting point of the internal magnetic field zone 31a is located on the X-axis near the end point of the spiral line segment CG. The end point of the internal magnetic field zone 31a is located on the line connecting the end point of the first straight line segment HG and the rotation center of impeller 4. The closest distance between the internal magnetic field zone 31a and impeller 4 is d4, where d4 = d5 * g1. d5 is the shortest distance between impeller 4 and volute tongue line segment BC, and g1 is the first preset value. The value range of g1 is: 1.5 ≤ g1 ≤ 2.

[0075] The magnetic field band of the external airflow adjustment unit 32 is denoted as the external magnetic field band 32a. The external magnetic field band 32a is annular with a width of d2. The starting point of the external magnetic field band 32a is from the opening A1 of the spiral segment CG. The end of the external magnetic field band 32a is located on the horizontal line of the lowest tangent point of the first straight segment HG and the volute tongue segment BC. The value of A1 is: A1 = A3 * g2, where A3 is the maximum opening of the spiral segment CG, and g2 is the second preset value, 1 / 3 ≤ g2 ≤ 1 / 2. The distance from the outer side of the external magnetic field band 32a to the volute shape is d3, where d3 = A1 * g3, and g3 is the third preset value. The value range of g3 is: 0.1 ≤ g3 ≤ 0.3.

[0076] Other examples Figure 5 As shown, the airflow detection strip 31b of the inner airflow adjustment unit 31 is set to fit against the outer side of the inner magnetic field strip 31a and is in the same direction of extension of the inner magnetic field strip 31a; and / or the airflow detection strip 32b of the outer airflow adjustment unit 32 is set to fit against the outer side of the outer magnetic field strip 32a and is in the same direction of extension of the outer magnetic field strip 32a. Figure 5 The arrows in the diagram indicate the airflow direction, and the airflow angle r is detected by the airflow detection strip.

[0077] The control method for the range hood in this embodiment includes the following steps:

[0078] Step 1: Start the centrifugal fan and set the initial value of the airflow adjustment number w to 1;

[0079] Step 2: Obtain the air volume q1 of the centrifugal fan in its current state;

[0080] In this embodiment, the air volume q1 can be determined based on the impeller speed and the pressure at the volute outlet 10b under the current conditions;

[0081] Step 3: Calculate the required gas-mixture flow rate q2. The formula for calculating q2 is:

[0082]

[0083] Where e1 is the preset average charge per unit of oil fume, and e2 is the charge per unit of mixed gas;

[0084] Step 4: Control the nozzle of the atomizer to spray charged gas particles into the inner cavity of the volute at a flow rate of q2;

[0085] Step 5: Monitor the airflow angle at the airflow detection zone of the inner airflow adjustment unit and the airflow angle at the airflow detection zone of the outer airflow adjustment unit respectively, and calculate the inner flow coefficient m1 based on the airflow angle at the airflow detection zone of the inner airflow adjustment unit and the outer flow coefficient m2 based on the airflow angle at the airflow detection zone of the outer airflow adjustment unit.

[0086] The formula for calculating m1 is:

[0087]

[0088] Where k1 is the first speed coefficient, r 1i r is the airflow angle monitored at the i-th position in the internal airflow adjustment unit. a The preset airflow angle threshold for the internal airflow adjustment unit;

[0089] The formula for calculating m2 is:

[0090]

[0091] Where k2 is the second speed coefficient, r 2j r is the airflow angle monitored at the j-th position in the external airflow adjustment unit. b The preset airflow angle threshold for the external airflow adjustment unit;

[0092] The actual values ​​of the first and second speed coefficients mentioned above are determined based on the impeller speed; the higher the impeller speed, the smaller the value.

[0093] Step 6: Determine if the following conditions are met: m1≤M1 and m2≤M2, where M1 is the first preset threshold and M2 is the second preset threshold. If yes, the range hood is operating normally and the process ends; otherwise, proceed to step 7.

[0094] Step 7: Adjust the airflow in the current centrifugal fan for the wth time, and determine whether the current airflow adjustment is successful. If yes, proceed to step 9; otherwise, proceed to step 8.

[0095] In this embodiment, the specific steps for adjusting the airflow within the centrifugal fan are as follows:

[0096] Step 7-1: Set the initial value of the airflow adjustment operation number n1 to 1;

[0097] Step 7-2: Determine if m1 is greater than M1. If yes, proceed to step 7-3; otherwise, proceed to step 7-7.

[0098] Step 7-3: Determine whether the magnetic field adjustment time t1 of the internal airflow adjustment unit is greater than the preset time t2. The preset time t2 is related to the impeller speed fluctuation. The greater the impeller speed fluctuation, the smaller t2 is. If yes, proceed to step 7-6; otherwise, proceed to step 7-4.

[0099] Step 7-4: Calculate and generate the magnetic induction intensity distribution map G1 of the internal magnetic field induction zone based on the airflow angle data of each point on the airflow detection zone of the internal airflow adjustment unit.

[0100] The calculation method for the magnetic induction intensity distribution map G1 of the aforementioned internal magnetic field induction zone is existing technology and will not be elaborated further here;

[0101] Step 7-5: Activate the magnetic field band of the internal airflow adjustment unit according to the distribution map G1, and proceed to step 7-2;

[0102] Step 7-6: Let t1 = 0;

[0103] Step 7-7: Set the initial value of the external magnetic field adjustment number n3 to 0;

[0104] Step 7-8: Determine if m2 is greater than M2. If yes, proceed to step 7-9; otherwise, proceed to step 7-11.

[0105] Step 7-9: Determine whether the number of external magnetic field adjustments n3 is greater than the first preset threshold n4. If yes, proceed to step 7-13; otherwise, add 1 to the value of n3, update n3, and proceed to step 7-10.

[0106] Steps 7-10: Calculate and generate the magnetic induction intensity distribution map G2 of the external magnetic field induction zone based on the airflow angle data of each point on the airflow detection zone of the external airflow adjustment unit, start the magnetic field zone of the external airflow adjustment unit based on the distribution map G2, and proceed to step 7-8.

[0107] Steps 7-11: Calculate the internal flow coefficient m1 based on the airflow angle at the airflow detection zone of the internal airflow adjustment unit and the external flow coefficient m2 based on the airflow angle at the airflow detection zone of the external airflow adjustment unit.

[0108] Step 7-12: Determine if the following conditions are met: m1≤M1 and m2≤M2. If yes, the adjustment is successful; otherwise, proceed to step 7-13.

[0109] Step 7-13: Determine whether n1 is greater than or equal to the second preset threshold n5. If yes, the adjustment fails; if no, add 1 to the value of n1 and update n1, then proceed to step 7-2.

[0110] Step 8: Determine if w is greater than or equal to W, where W is the preset number of times. If yes, proceed to step 9; otherwise, add 1 to the value of w and update the value of w, increase e1 to k3*e1, where k3 is the preset value and k3>1, and then proceed to step 3 again.

[0111] In this embodiment, the range of values ​​for k3 is: To calculate the Wth root of 2;

[0112] Step 9: Run the magnetic field bands of the internal airflow adjustment unit and the external airflow adjustment unit according to the magnetic field after the current airflow adjustment.

[0113] In this embodiment, the charge (positive / negative) of the gas ejected by the atomizer is related to the direction of the magnetic field formed by the magnetic field bands on the front and rear covers of the volute. This relationship ensures that the Lorentz force on the charged particles always has a positive component in the impeller rotation direction. Therefore, this method achieves real-time optimization and adjustment of the airflow direction through non-contact control, enhancing the precise control of airflow within the volute and making the airflow smoother. It ensures the stability of airflow within the volute in real time, regardless of the operating conditions of the centrifugal fan, and allows the centrifugal fan to achieve optimal performance, greatly expanding its application scenarios. Furthermore, this method breaks through traditional volute design methods, compensating for flow differences caused by changes in fluid properties, and expanding new performance optimization methods for fan volutes. Additionally, the use of a two-stage airflow angle adjustment method makes the adjustment process smoother and more convenient.

Claims

1. A volute for centrifugal fan, comprising: a front cover plate (11) provided with a front air inlet (10a) penetrating through a wall thickness thereof; a rear cover plate (12) oppositely spaced apart from the front cover plate (11); a ring wall (13) provided between the front cover plate (11) and the rear cover plate (12), and the ring wall (13), the front cover plate (11) and the rear cover plate (12) jointly delimit a volute inner cavity (14) and an air outlet (10b) at a top portion; characterized in further comprising: an atomizer (2) provided at the front air inlet (10a), the atomizer (2) is provided with a plurality of through holes (21) for airflow to pass through, and a plurality of nozzles (22) for spraying charged gas particles into the volute inner cavity (14) are formed on the atomizer (2); an airflow adjusting assembly (3) comprising airflow adjusting units (31, 32) provided on an outer surface of the front cover plate (11), the airflow adjusting units (31, 32) comprise magnetic field bands (31a, 32a) for forming magnetic fields and airflow detection bands (31b, 32b) for detecting airflow, and the airflow adjusting assembly (3) is configured to control the magnetic field bands (31a, 32a) to generate corresponding magnetic fields according to the airflow detected by the airflow detection bands (31b, 32b), and to adjust the airflow by cooperating the magnetic fields with the charged gas particles.

2. The volute for a centrifugal fan according to claim 1, characterized by: The airflow adjusting units (31, 32) on the outer surface of the front cover plate (11) are two, which are an inner airflow adjusting unit (31) and an outer airflow adjusting unit (32) provided on the periphery of the inner airflow adjusting unit (31), the inner airflow adjusting unit (31) is provided around at least a part of the outer periphery of the front cover plate (11) adjacent to the front air inlet (10a), and the outer airflow adjusting unit (32) is provided along at least a part of the outer periphery of the front cover plate (11).

3. The volute for a centrifugal fan according to claim 2, characterized by: The centrifugal fan comprises an impeller (4) provided in the volute, and a profile line of the volute comprises a first straight line segment (HG), a spiral line segment (CG), a volute tongue profile line segment (BC) and a second straight line segment (AB) sequentially arranged and smoothly connected in a circumferential direction, and starting points and ending points of the first straight line segment (HG) and the second straight line segment (AB) correspond to two ends of the air outlet (10b) of the volute (10) respectively.

4. The volute for a centrifugal fan according to claim 3, characterized by: Taking a rotation center (o) of the impeller (4) as a coordinate origin, a horizontal line passing through the origin as an X-axis, the magnetic field band of the inner airflow adjusting unit (31) is recorded as an inner magnetic field band (31a), the inner magnetic field band (31a) is annular and has a width of d1, a starting point of the inner magnetic field band (31a) is on the X-axis and close to a side of an ending point of the spiral line segment (CG), and an ending point of the inner magnetic field band (31a) is on a line connecting the ending point of the first straight line segment (HG) and the rotation center of the impeller (4).

5. The volute for a centrifugal fan of claim 4, wherein: A nearest distance of the inner magnetic field band (31a) to the impeller (4) is d4, d4=d5*g1, d5 is a shortest distance between the impeller (4) and the volute tongue profile line segment (BC), and g1 is a first preset value, and a value range of g1 is 1.5≤g1≤2.

6. The volute for a centrifugal fan of claim 4, wherein: The magnetic field band of the outer airflow adjusting unit (32) is denoted as an outer magnetic field band (32a), the outer magnetic field band (32a) is annular and has a width of d2, the starting point of the outer magnetic field band (32a) is from the opening A1 of the spiral segment (CG), and the terminal of the outer magnetic field band (32a) is located on the horizontal line of the lowest tangent point of the first straight segment (HG) and the volute segment (BC).

7. The volute for a centrifugal fan of claim 6, wherein: The A1 is A1=A3*g2, A3 is the maximum opening of the spiral segment (CG), g2 is a second preset value, and 1 / 3≤g2≤1 / 2.

8. The volute for a centrifugal fan of claim 7, wherein: The outer side of the outer magnetic field band (32a) is away from the volute distance d3, d3=A1*g3, g3 is a third preset value, and 0.1≤g3≤0.

3.

9. The volute for a centrifugal fan of claim 8, wherein: The airflow detection band (31b) of the inner airflow adjusting unit (31) is arranged on the outer side of the inner magnetic field band (31a) and has the same extension direction as the inner magnetic field band (31a); and / or the airflow detection band (32b) of the outer airflow adjusting unit (32) is arranged on the outer side of the outer magnetic field band (32a) and has the same extension direction as the outer magnetic field band (32a).

10. The volute for a centrifugal fan according to any one of claims 2 to 9, characterized in that: The outer surface of the rear cover plate (12) is also provided with the airflow adjusting unit.

11. The volute for a centrifugal fan of claim 10, wherein: The atomizer (2) comprises a cross-shaped support rod (20), the end of the support rod (20) is constrained on the front cover plate (11), and the plurality of nozzles (22) are respectively and separately arranged on the support rod (20) at intervals.

12. The volute for a centrifugal fan of claim 11, wherein: The atomizer (2) further comprises a plurality of circular rings (23) arranged in sequence and at intervals, each circular ring (23) is constrained on the support rod (20) and arranged with the same center as the support rod (20), and each circular ring (23) and the support rod (20) jointly limit the through hole (21).

13. A centrifugal fan characterized by: The volute for a centrifugal fan comprises the volute according to any one of claims 2-12.

14. A range hood characterized by: The centrifugal fan comprises the centrifugal fan according to claim 13.

15. A control method for a range hood as set forth in claim 14 wherein The method comprises the following steps: Step 1, starting the centrifugal fan, and setting the initial value of the airflow adjustment frequency w as 1; Step 2, obtaining the air volume q1 under the current state of the centrifugal fan; Step 3, calculating the required mixed air volume q2, the calculation formula of q2 is: Wherein, e1 is the preset average unit oil fume charge, and e2 is the unit charge of the mixed air; Step 4, controlling the nozzles of the atomizer to spray the charged gas particles into the inner cavity of the volute at the flow rate q2; Step 5, respectively monitoring the airflow angles at the airflow detection bands of the inner airflow adjusting unit and the outer airflow adjusting unit, calculating the inner flow coefficient m1 according to the airflow angle at the airflow detection band of the inner airflow adjusting unit, and calculating the outer flow coefficient m2 according to the airflow angle at the airflow detection band of the outer airflow adjusting unit; Step 6, judging whether the following conditions are met: m1≤M1 and m2≤M2, M1 is a first preset threshold, M2 is a second preset threshold, if yes, the current range hood is running normally, and the method ends; if not, the method proceeds to step 7. Step 7, adjust the airflow in the centrifugal fan for the wth time, and determine whether the current airflow adjustment is successful, if yes, go to step 9; if no, go to step 8; Step 8, determine whether w is greater than or equal to W, W being a preset number of times, if yes, go to step 9; if no, update the value of w by adding 1 to it, increase e1 to k3*e1, k3 being a preset value and k3>1, and go to step 3 again; Step 9, run the magnetic field bands of the inner airflow adjustment unit and the outer airflow adjustment unit according to the magnetic field after the current airflow adjustment.

16. The control method according to claim 15, characterized in that: The calculation formula of m1 is: wherein k1 is a first rotational speed coefficient, r 1i is an airflow angle monitored by the i-th position of the inner airflow adjustment unit, r a is a preset airflow angle threshold value of the inner airflow adjustment unit.

17. The control method according to claim 16, characterized in that: The calculation formula of m2 is: wherein k2 is a second rotational speed coefficient, r 2j is the airflow angle monitored by the jth position of the outside airflow adjustment unit, r b is a preset airflow angle threshold value of the outside airflow adjustment unit.

18. The control method according to claim 17, characterized by: The value of k3 in step 8 is in the range of: To calculate the Wth root of 2.

19. The control method according to any one of claims 15 to 18, characterized in that: The specific steps of adjusting the airflow in the centrifugal fan in step 7 are as follows: Step 7-1, set the initial value of the airflow adjustment running number n1 to 1; Step 7-2, determine whether m1 is greater than M1, if yes, go to step 7-3; if no, go to step 7-7; Step 7-3, determine whether the magnetic field band adjustment time t1 of the inner airflow adjustment unit is greater than a preset time t2, the preset time t2 being related to the impeller speed fluctuation; if yes, go to step 7-6; if no, go to step 7-4; Step 7-4, calculate and generate the inner magnetic field induction band magnetic induction intensity distribution graph G1 according to the airflow angle data of each point on the airflow detection band of the inner airflow adjustment unit; Step 7-5, start the magnetic field band of the inner airflow adjustment unit according to the distribution graph G1, and go to step 7-2; Step 7-6, set t1=0; Step 7-7, set the initial value of the outer magnetic field adjustment number n3 to 0; Step 7-8, determine whether m2 is greater than M2, if yes, go to step 7-9; if no, go to step 7-11; Step 7-9, determine whether the outer magnetic field adjustment number n3 is greater than a first preset threshold n4, if yes, go to step 7-13; if no, update n3 by adding 1 to it, and go to step 7-10; Step 7-10, calculate and generate the outer magnetic field induction band magnetic induction intensity distribution graph G2 according to the airflow angle data of each point on the airflow detection band of the outer airflow adjustment unit, start the magnetic field band of the outer airflow adjustment unit according to the distribution graph G2, and go to step 7-8; Step 7-11, calculate the inner flow coefficient m1 according to the airflow angle at the airflow detection band of the inner airflow adjustment unit, and calculate the outer flow coefficient m2 according to the airflow angle at the airflow detection band of the outer airflow adjustment unit; Step 7-12, determine whether the following conditions are met: m1≤M1 and m2≤M2, if yes, the adjustment is successful; if no, go to step 7-13; Step 7-13, determine whether n1 is greater than or equal to a second preset threshold n5, if yes, the adjustment fails; if no, update n1 by adding 1 to it, and go to step 7-2.

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