Flow collector for fan system, fan system and range hood

Abstract

The invention relates to a current collector for a fan system, the fan system and a range hood, the current collector comprises: an annular mounting part having a central axis and forming a first direction and a second direction opposite to each other along the central axis, the second direction being a lampblack flow path direction; the flow guide part comprises a radial flow guide part and an axial flow guide part extending from the inner side of the radial flow guide part in the second direction; the flow guide part comprises a first flow guide section and a second flow guide section which are sequentially connected in the circumferential direction; the air guide heights (H1 and H3) of the two flow guide sections, the flow guide lengths (H2 and H4) of the axial flow guide parts and the radial sizes (R1 and R2) are different, the problem of inlet leakage backflow is solved at the same time from the three dimensions of the axial direction, the radial direction and the circumferential direction, airflow can be better guided to enter the volute, the turbulence intensity of the lower portion in the volute is further effectively improved, and therefore the efficiency of the fan is improved, and the service life of the fan is prolonged. And noise is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fan systems, and in particular to a collector for a fan system, a fan system, and a range hood. Background Art

[0002] Range hoods utilize a fan system (typically a centrifugal fan) to extract oil-laden air from the kitchen and discharge it into a common flue or directly outdoors. To improve air inflow, increase fan efficiency, and reduce noise, a flow collector is typically installed at the fan inlet. This collector's function is to smoothly direct the airflow toward the impeller. Using a flow collector effectively improves fan performance, resulting in higher flow rates and, operating under designed conditions, lower noise levels.

[0003] Because the centrifugal fans commonly used in range hoods are multi-blade centrifugal fans, their volutes are asymmetrically shaped like logarithmic spirals, resulting in an asymmetrical flow field. Flow collectors are typically designed with a symmetrical, circular, rotational shape. For example, Chinese Patent Application No. 201110432232.0 discloses a multi-blade centrifugal fan with a multi-function flow guide. The multi-function flow guide comprises a flow collector and a fan body. The multi-function flow guide includes a flow collector and a flow guide, and is connected to the fan body via mounting edges on the flow collector. This type of collector is designed based on the assumption of circumferentially uniform air intake, similar to that of axial flow fans, and is generally a symmetrical structure. The multi-blade centrifugal fan used in range hoods is a radial fan in itself, and the fan is mostly installed in a box. Unlike axial flow fans, it does not have 360° circumferentially uniform air intake, and the airflow needs to be turned from axial to radial. From the external environment, the operating environment of the range hood is complex and is affected by the smoke pipe, public flue resistance, public flue back pressure, etc. Ordinary collectors designed in a traditional way will have severe inlet vortices and turbulence, and serious internal leakage and backflow, resulting in weak adaptability to working conditions, low overall efficiency, and high noise.

[0004] Therefore, the existing current collector needs to be further improved. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a flow collector that can effectively improve the inlet leakage backflow problem and thus better guide the airflow into the interior of the volute in response to the current status of the existing technology.

[0006] The second technical problem to be solved by the present invention is to provide a fan system that can effectively improve the inlet leakage backflow problem and thus better guide the airflow into the interior of the volute in response to the current status of the existing technology.

[0007] The third technical problem to be solved by the present invention is to provide a range hood using the above-mentioned fan system in view of the current status of the existing technology.

[0008] The technical solution adopted by the present invention to solve the first technical problem is: a collector for a fan system, which is used to be arranged at the air inlet of the fan system, comprising:

[0009] The annular mounting portion has a central axis, and forms a first direction and a second direction opposite to the central axis, wherein the second direction is the direction of the oil smoke flow path;

[0010] The guide portion includes a radial guide portion extending radially inward from the inner side of the annular mounting portion and bending and protruding in a first direction, and an axial guide portion extending from the inner side of the radial guide portion along a second direction;

[0011] The guide portion includes a first guide segment and a second guide segment connected in sequence in the circumferential direction thereof, wherein a central angle formed by the second guide segment relative to the central axis of the annular mounting portion is denoted as S, and a value range of S is: 30°<S<180°;

[0012] The protruding height of the radial guide portion of the first guide section relative to the annular mounting portion along the first direction is recorded as H1, the distance between the side edge of the axial guide portion of the first guide section away from the annular mounting portion and the annular mounting portion in the extension direction of the above-mentioned central axis is recorded as H2, the distance between the axial guide portion of the first guide section and the central axis of the above-mentioned annular mounting portion is recorded as R1, the protruding height of the radial guide portion of the second guide section relative to the annular mounting portion along the first direction is recorded as H3, the distance between the side edge of the axial guide portion of the second guide section away from the annular mounting portion and the annular mounting portion in the extension direction of the above-mentioned central axis is recorded as H4, and the distance between the axial guide portion of the second guide section and the central axis of the above-mentioned annular mounting portion is recorded as R2, wherein H3>H1, H4>H2, and R2 is smaller than R1.

[0013] In general, in order to ensure the air volume and avoid interference with other components, the above parameters H1, H2, H3, H4, R1, and R2 meet the following conditions:

[0014] H1<H3<1.5H1;

[0015] H4=H2+a,0mm<a<5mm;

[0016] 0.85R1<R2<0.95R1.

[0017] In order to ensure that the collector is compatible with the inner diameter of the impeller, the inner radius of the impeller of the fan system is R, and the above R1 and R meet the conditions:

[0018] R1=Rt, t=5~20mm.

[0019] In order to fit the air inlet of the volute, the distance between the inner edge of the annular mounting portion and the central axis of the annular mounting portion is recorded as R0, R0 = (1.1-1.4) * R1.

[0020] As an improvement, the value range of H1 is: 5mm≤H1≤15mm, and the value range of H2 is: 5mm≤H2≤20mm.

[0021] As an improvement, the distance that the axial guide portion of the first guide section extends from the radial guide portion thereof along the second direction is recorded as L1, and the value range of L1 is: 0mm<L1<6mm.

[0022] As an improvement, the contour line of the cross section of the radial guide portion of the first guide section is recorded as a first contour line, the point where the first contour line connects with the annular mounting portion is recorded as A, the point on the first contour line that is farthest from the annular mounting portion along the first direction is recorded as B, and a point on the arc segment formed between point A and point B on the first contour line is recorded as point M. The contour line of the cross section of the radial guide portion of the second guide section is recorded as a second contour line, the point where the second contour line connects with the annular mounting portion is recorded as A', the point on the second contour line that is farthest from the annular mounting portion along the first direction is recorded as B', and a point on the arc segment formed between point A' and point B' on the second contour line is recorded as point M'. The radius of curvature of the arc segment AM on the first contour line is the same as the radius of curvature of the arc segment A'M' on the second contour line, and the radius of curvature of the arc segment M'B' on the second contour line is greater than the radius of curvature of the arc segment MB on the first contour line.

[0023] The structural design in which the curvature radius of the arc segment AM on the first contour line is the same as the curvature radius of the arc segment A'M' on the second contour line can make the airflow more stable during the initial flow process, avoid serious flow separation problems caused by the large difference in the curvature radius between the first contour line and the second contour line, and ensure that the airflow can be guided into the volute more smoothly.

[0024] Generally speaking, the length ratio of the arc segment AM on the first contour line should be reasonably limited. If the arc length ratio of the arc segment AM on the first contour line is too large, the second air guide segment cannot effectively increase the turning radius, which is not conducive to improving the diversion effect. If the arc length ratio of the arc segment AM on the first contour line is too small, the overlapping area between the second air guide segment and the first air guide segment is small, the airflow is unstable during the initial flow process, and the airflow cannot be smoothly guided into the volute. For this reason, the arc length of the arc segment AM on the first contour line is recorded as L AM The arc length of the arc segment AB on the first contour line is recorded as L AB , where 0<L AM <0.5L AB .

[0025] The technical solution adopted by the present invention to solve the second technical problem is: a fan system, including a volute, the volute is provided with an air inlet, the air inlet is provided with a collector, and the collector adopts the above-mentioned collector for the fan system.

[0026] As an improvement, the volute also has an air outlet, the opening of the air outlet faces upward, and the vertical plane passing through the central axis of the annular mounting portion of the collector is used as a reference plane. The second guide section on the collector is located at the bottom, and the reference plane divides the second guide section into a left guide section and a right guide section. The central angle of the left guide section with the central axis of the annular mounting portion as the center is recorded as α, and the central angle of the right guide section with the central axis of the annular mounting portion as the center is recorded as β, wherein 90°≥α>β≥15°.

[0027] Because the left side below the collector is close to the volute outlet, the air flow at the collector inlet is larger than that on the right side. The larger the air flow, the larger the turning radius required for the collector, and the better its guiding effect. Therefore, the above setting is adopted: α>β.

[0028] The technical solution adopted by the present invention to solve the third technical problem is: a range hood, including a fan system, and the fan system adopts the above-mentioned fan system.

[0029] Compared with the prior art, the advantages of the present invention are as follows: for the fan system placed in the range hood casing, that is, to improve the airflow in a limited space from the box into the fan, the present invention designs the guide part of the collector as a first guide section and a second guide section connected in sequence in its circumferential direction, and the two guide sections have different air guide heights (that is, H1 and H3), guide lengths of the axial guide parts (that is, H2 and H4), and radial dimensions (that is, R1 and R2), which improve the inlet leakage backflow problem from the axial, radial and circumferential dimensions at the same time, can better guide the airflow into the interior of the volute, and further effectively improve the turbulence intensity below the interior of the volute, thereby improving the fan efficiency and reducing noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the three-dimensional structure of a fan system according to an embodiment of the present invention;

[0031] Figure 2 A front view of a fan system according to an embodiment of the present invention;

[0032] Figure 3 for Figure 2 A cross-sectional view of the fan system along the AA direction;

[0033] Figure 4 is a schematic diagram of the three-dimensional structure of a current collector according to an embodiment of the present invention;

[0034] Figure 5 This is a front view of a current collector according to an embodiment of the present invention;

[0035] Figure 6 for Figure 5 A cross-sectional view of the current collector in FIG. 1 taken along the AA direction;

[0036] Figure 7 for Figure 5 A cross-sectional view of the current collector in FIG. 1 taken along the BB direction;

[0037] Figure 8 for Figure 5 The main view of the cross section of the collector after being cut along the AA direction;

[0038] Figure 9 Schematic diagram comparing the turbulent kinetic energy of the flow field of the cross section at different axial positions of the fan system of the present invention and the existing fan system. DETAILED DESCRIPTION

[0039] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0040] In the present specification and claims, directional terms such as "front," "back," "up," "down," "left," "right," "side," "top," and "bottom" are used to describe various exemplary structural parts and components of the present invention. However, these terms are used herein for convenience of description only and are based on the exemplary orientations shown in the accompanying drawings. Because the embodiments disclosed herein can be arranged in various orientations, these directional terms are intended for illustrative purposes only and should not be construed as limiting. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0041] Figures 1-9 A preferred embodiment of the present invention's flow collector for a fan system, a fan system, and a range hood is shown. The range hood includes a housing and a fan system disposed within the housing. The fan system of this embodiment is a centrifugal fan. The housing generally includes a fan frame and a fume hood disposed at the bottom of the fan frame. The inner cavity of the fan frame is connected to the inner cavity of the fume hood. An air suction port is provided on the front side wall of the fume hood, through which external smoke can enter the fume hood. A centrifugal fan is disposed within the fan frame. When the centrifugal fan is in operation, negative pressure is generated, and external oil smoke can be sucked into the fume hood through the air suction port.

[0042] The centrifugal fan includes a volute 10, an impeller 14, and a motor 15 for driving the impeller 14 to rotate. The volute 10 includes a front cover plate 11, a rear cover plate 12, and an annular wall 13 connecting the front cover plate 11 and the rear cover plate 12. The two ends of the annular wall 13, together with the front cover plate 11 and the rear cover plate 12, define an air outlet 100 for the airflow of the volute 10 to flow out. An air inlet 110 is provided on the front cover plate 11 of the volute 10. The impeller 14 is arranged inside the volute 10, and the front end of the impeller 14 is opposite to the above-mentioned air outlet 100. A collector 2 is also provided at the air inlet 110 of the volute 10. For a centrifugal fan, the collector 2 plays a role in guiding the flow and plays a decisive role in the inlet airflow conditions of the impeller 14, thereby affecting the aerodynamic performance of the internal flow field of the impeller 14 and the actual operating performance of the fan.

[0043] Since the fan system is arranged in the range hood casing, in order to effectively improve the airflow in the limited space from the box into the fan, this embodiment has made adaptive improvements to the collector. Specifically, the collector 2 includes an annular mounting portion 21 and a guide portion, wherein the annular mounting portion 21 has a central axis, which is basically collinear with the axis of the impeller 14, and forms opposite first directions A1 and second directions A2 along the central axis, wherein the second direction A2 is the direction of the oil fume flow path.

[0044] The guide portion includes a radial guide portion 22 and an axial guide portion 23, wherein the radial guide portion 22 extends radially inward from the inner side of the annular mounting portion 21 and bends and protrudes in the first direction A1, as shown in FIG. Figure 6 As shown, the cross section of the radial guide portion 22 is an arc shape with its opening facing the inside of the volute 10. The axial guide portion 23 is a section extending from the inner side of the radial guide portion 22 along the second direction A2.

[0045] The air outlet 100 of the volute 10 faces upward, and the air inlet 110 faces forward. Taking the vertical plane of the central axis of the annular mounting portion 21 of the collector as the reference plane, the air outlet 100 is set to the left relative to the reference plane. The guide portion of this embodiment includes a first guide section 241 and a second guide section 242 that are sequentially connected in the circumferential direction thereof, wherein the second guide section 242 is located at the bottom, and the central angle formed by the second guide section 242 relative to the central axis of the annular mounting portion 21 is recorded as S, and the value range of S is: 30°<S<180°. The reference plane divides the second guide section 242 into a left guide section and a right guide section, and the central angle of the left guide section corresponding to the central axis of the annular mounting portion 21 is recorded as α, and the central angle of the right guide section corresponding to the central axis of the annular mounting portion 21 is recorded as β, wherein 90°≥α>β≥15°. Because the left side below the collector is close to the outlet of the volute 10, the air flow at the collector inlet is larger than that on the right side. The larger the air flow, the larger the turning radius required for the collector, and the better its guiding effect. Therefore, the above setting is adopted: α>β.

[0046] See also Figure 8 , the protruding height of the radial guide portion 22 of the first guide section 241 relative to the annular mounting portion 21 along the first direction A1 is recorded as H1, the distance between the side edge of the axial guide portion 23 of the first guide section 241 away from the annular mounting portion 21 and the annular mounting portion 21 in the extension direction of the above-mentioned central axis is recorded as H2, the distance between the axial guide portion 23 of the first guide section 241 and the central axis of the above-mentioned annular mounting portion 21 is recorded as R1, the protruding height of the radial guide portion 22 of the second guide section 242 relative to the annular mounting portion 21 along the first direction A1 is recorded as H3, the distance between the side edge of the axial guide portion 23 of the second guide section 242 away from the annular mounting portion 21 and the annular mounting portion 21 in the extension direction of the above-mentioned central axis is recorded as H4, and the distance between the axial guide portion 23 of the second guide section 242 and the central axis of the above-mentioned annular mounting portion 21 is recorded as R2, wherein H3>H1, H4>H2, and R2 is smaller than R1. Specifically, under normal circumstances, in order to ensure the air intake volume and avoid interference with other components, the above parameters H1, H2, H3, H4, R1, and R2 meet the conditions: H1<H3<1.5H1; H4=H2+a, 0mm<a<5mm; 0.85R1<R2<0.95R1, the value range of H1 is: 5mm≤H1≤15mm, and the value range of H2 is: 5mm≤H2≤20mm.

[0047] The inner radius of the impeller 14 of the fan system is R, then the above R1 and R meet the condition: R1 = Rt, where t = 5 to 20 mm. The distance between the inner edge of the annular mounting portion 21 and the central axis of the annular mounting portion 21 is recorded as R0, R0 = (1.1 to 1.4) * R1. The distance that the axial guide portion 23 of the first guide section 241 extends from its radial guide portion 22 along the second direction A2 is recorded as L1, and the value range of L1 is: 0 mm < L1 < 6 mm. The distance that the axial guide portion 23 of the second guide section 242 extends from its radial guide portion 22 along the second direction A2 is recorded as L2, and the value of L2 is basically the same as L1.

[0048] Continue to see Figure 6 and Figure 7, the contour line of the cross section of the radial guide portion 22 of the first guide section 241 is recorded as the first contour line, the point where the first contour line connects with the annular mounting portion 21 is recorded as A, the point where the first contour line connects with the axial guide portion 23 is recorded as C, the point on the first contour line farthest from the annular mounting portion 21 along the first direction A1 is recorded as B, the point on the first contour line corresponding to the end position of the axial guide portion is recorded as D, and a point on the arc segment formed between point A and point B on the first contour line is recorded as point M. Correspondingly, the contour line of the cross section of the radial guide portion 22 of the second guide section 242 is recorded as the second contour line. The second contour line is set based on the wind guide characteristics of the first contour line and has a certain relationship to ensure the best guide and backflow prevention effect. The second contour line and the annular mounting portion 21 are connected in the first direction A1 and the axial guide portion 23 ... A point connected to the annular mounting portion 21 is recorded as A', a point connected to the axial flow guide portion 23 is recorded as C', a point on the second contour line that is farthest from the annular mounting portion 21 along the first direction A1 is recorded as B', a point on the second contour line corresponding to the end position of the axial flow guide portion is recorded as D', and a point on the arc segment formed between point A' and point B' on the second contour line is recorded as point M', wherein the curvature radius of the arc segment AM on the first contour line is the same as the curvature radius of the arc segment A'M' on the second contour line, the curvature radius of the arc segment M'B' on the second contour line is larger than the curvature radius of the arc segment MB on the first contour line, and the curvature radius of the arc segment B'C' on the second contour line is also larger than the curvature radius of the arc segment BC on the first contour line. The above structural design makes the air-guiding characteristics of the second air-guiding section different from those of the first air-guiding end in both axial and radial directions. The air-guiding height of the second air-guiding section is higher (i.e., H1 is smaller than H3), which increases the turning radius and enhances the air-guiding effect. The second air-guiding section has a smaller inner diameter (i.e., R2 is smaller than R1) and a deeper insertion depth (i.e., H4 is greater than H2), which enhances the anti-backflow effect of the leading edge of the impeller 14. The collector of this embodiment improves the inlet leakage backflow problem from three dimensions: axial, radial, and circumferential. It can better guide the airflow into the interior of the volute 10 and further effectively improve the turbulence intensity below the interior of the volute 10, thereby improving the efficiency of the fan and reducing noise. On this basis, the structural design in which the curvature radius of the arc segment AM on the first contour line is the same as the curvature radius of the arc segment A'M' on the second contour line can make the airflow more stable during the initial flow process, avoid serious flow separation problems caused by the large difference in curvature radius between the first contour line and the second contour line, and ensure that the airflow can be guided more smoothly into the interior of the volute 10.

[0049] Generally speaking, the length ratio of the arc segment AM on the first contour line should be reasonably limited. If the arc length ratio of the arc segment AM on the first contour line is too large, the second air guide segment cannot effectively increase the turning radius, which is not conducive to improving the diversion effect. If the arc length ratio of the arc segment AM on the first contour line is too small, the overlapping area between the second air guide segment and the first air guide segment is small, the airflow is unstable during the initial flow process, and the airflow cannot be smoothly guided into the interior of the volute 10. For this reason, the arc length of the arc segment AM on the first contour line is recorded as L AM , the arc length of the arc segment AB on the first contour line is recorded as L AB , where 0<L AM <0.5L AB .

[0050] Continue to see Figure 8 The angle formed by the intersection of the straight line segment corresponding to the axial guide portion 23 on the first contour line of the first guide section 241 and the plane where the annular mounting portion 21 is located is recorded as ω1, and the angle formed by the intersection of the straight line segment corresponding to the axial guide portion 23 on the second contour line of the second guide section 242 and the plane where the annular mounting portion 21 is located is recorded as ω2, where the value ranges of ω1 and ω2 are both: 90°~110°.

[0051] Figure 9 The figure shows a schematic diagram comparing the flow field turbulent kinetic energy of the cross-sections of the fan system of this embodiment and the existing fan system at different axial positions, where Z is the axial direction of the impeller 14, and the origin is located on the rear cover 12 of the volute 10. Affected by the airflow turning radius and the leakage between the collector and the impeller 14, the middle end Z = 85mm is the main air intake area of ​​the impeller 14. It can be seen from the figure that the red high-intensity turbulent kinetic energy TKE inside the lower edge of the volute 10 of this embodiment (corresponding to the double-diameter section of the collector) and at the outlet is significantly reduced. Even in the non-mainstream area, the cross-section of the Z = 150 area near the collector and other cross-sections, the red high-intensity turbulent kinetic energy inside the volute 10 is somewhat reduced. This shows that the double-force collector is helpful in improving the turbulence intensity inside the volute 10. The low turbulence intensity means that there are fewer vortices in the volute 10, and the fan work efficiency can be improved.

Claims

1. A flow collector for a fan system, for being arranged at an air inlet (110) of the fan system, comprising: The annular mounting portion (21) has a central axis, and forms a first direction (A1) and a second direction (A2) opposite to each other along the central axis, wherein the second direction (A2) is the direction of the oil smoke flow path; The guide portion comprises a radial guide portion (22) extending radially inward from the inner side of the annular mounting portion (21) and bending and protruding in a first direction (A1), and an axial guide portion (23) extending from the inner side of the radial guide portion (22) along a second direction (A2); The invention is characterized in that: the guide portion comprises a first guide section (241) and a second guide section (242) connected in sequence in the circumferential direction thereof; the central angle formed by the second guide section (242) relative to the central axis of the annular mounting portion (21) is denoted as S, and the value range of S is: 30°<S<180°; The protruding height of the radial guide portion (22) of the first guide section (241) relative to the annular mounting portion (21) along the first direction (A1) is recorded as H1, the distance between the side edge of the axial guide portion (23) of the first guide section (241) away from the annular mounting portion (21) and the annular mounting portion (21) in the extension direction of the central axis is recorded as H2, the distance between the axial guide portion (23) of the first guide section (241) and the central axis of the annular mounting portion (21) is recorded as R1, and the distance between the radial guide portion (22) of the first guide section (241) and the annular mounting portion (21) is recorded as R2. ) relative to the annular mounting portion (21) along the first direction (A1) is recorded as H3, the distance between the side edge of the axial guide portion (23) of the second guide section (242) away from the annular mounting portion (21) and the annular mounting portion (21) in the extension direction of the above-mentioned central axis is recorded as H4, and the distance between the axial guide portion (23) of the second guide section (242) and the central axis of the above-mentioned annular mounting portion (21) is recorded as R2, wherein H3>H1, H4>H2, and R2 is smaller than R1.

2. The current collector for a fan system according to claim 1, characterized in that: The above parameters H1, H2, H3, H4, R1, and R2 meet the following conditions: H1<H3<1.5H1; H4=H2+a,0mm<a<5mm; 0.85R1<R2<0.95R1.

3. The current collector for a fan system according to claim 2, characterized in that: The inner radius of the impeller (14) of the fan system is R, and the above R1 and R meet the conditions: R1=Rt, t=5~20mm.

4. The current collector for a fan system according to claim 2, characterized in that: The distance between the inner edge of the annular mounting portion (21) and the central axis of the annular mounting portion (21) is recorded as R0, R0 = (1.1-1.4) * R1.

5. The current collector for a fan system according to claim 2, characterized in that: The value range of H1 is: 5mm≤H1≤15mm, and the value range of H2 is: 5mm≤H2≤20mm.

6. The current collector for a fan system according to claim 2, characterized in that: The distance that the axial flow guide portion (23) of the first flow guide section (241) extends from its radial flow guide portion (22) along the second direction (A2) is recorded as L1, and the value range of L1 is: 0mm<L1<6mm.

7. The current collector for a fan system according to any one of claims 1 to 6, characterized in that: The contour line of the cross section of the radial guide portion (22) of the first guide section (241) is recorded as a first contour line, a point where the first contour line meets the annular mounting portion (21) is recorded as A, a point on the first contour line that is farthest from the annular mounting portion (21) along the first direction (A1) is recorded as B, a point on the arc segment formed between point A and point B on the first contour line is recorded as point M, and the contour line of the cross section of the radial guide portion (22) of the second guide section (242) is recorded as a second contour line. A point where the contour line meets the annular mounting portion (21) is marked as A', a point on the second contour line that is farthest from the annular mounting portion (21) along the first direction (A1) is marked as B', a point on the arc segment formed between point A' and point B' on the second contour line is marked as point M', a curvature radius of the arc segment AM on the first contour line is the same as a curvature radius of the arc segment A'M' on the second contour line, and a curvature radius of the arc segment M'B' on the second contour line is greater than a curvature radius of the arc segment MB on the first contour line.

8. The current collector for a fan system according to claim 7, characterized in that: The arc length of the arc segment AM on the first contour line is denoted as L AM The arc length of the arc segment AB on the first contour line is recorded as L AB , where 0<L AM <0.5L AB .

9. A fan system, comprising a volute (10), wherein the volute (10) is provided with an air inlet (110), and a flow collector is provided at the air inlet (110), characterized in that: The current collector is the current collector for a fan system according to any one of claims 1 to 8.

10. The fan system according to claim 9, characterized in that: The volute (10) further comprises an air outlet (100), the opening of the air outlet (100) faces upward, and a vertical plane passing through the central axis of the annular mounting portion (21) of the collector is used as a reference plane. The second guide section (242) on the collector is located at the bottom, and the reference plane divides the second guide section (242) into a left guide section and a right guide section. The central angle of the left guide section with the central axis of the annular mounting portion (21) as the center is recorded as α, and the central angle of the right guide section with the central axis of the annular mounting portion (21) as the center is recorded as β, wherein 90°≥α>β≥15°.

11. A range hood, comprising a fan system, characterized in that: The fan system adopts the fan system according to claim 9 or 10.

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