CN116398468A

CN116398468A - Centrifugal fan and range hood with same

Info

Publication number: CN116398468A
Application number: CN202310495655.XA
Authority: CN
Inventors: 何立博
Original assignee: Ningbo Fotile Kitchen Ware Co Ltd
Current assignee: Ningbo Fotile Kitchen Ware Co Ltd
Priority date: 2023-04-28
Filing date: 2023-04-28
Publication date: 2023-07-07

Abstract

The invention discloses a centrifugal fan and a range hood with the same, wherein the centrifugal fan comprises an impeller, and the impeller comprises a disc and blades which are far away from an air inlet side; the centrifugal fan also comprises annular guide vanes which encircle the outlets of the blades and extend outwards along the radial direction of the centrifugal fan from the fixing positions of the guide vanes and the blades; along the axial direction of the centrifugal fan, at the same side of the disk far away from the air inlet side, the guide vanes are at least two arranged at intervals along the axial direction, and the height of the guide vanes gradually increases along with the increase of the distance from the disk far away from the air inlet side. Compared with the prior art, the invention has the advantages that: a series of guide vanes with different height and size are arranged at intervals at the outlets of the blades, the height of the guide vanes is unevenly matched with the axial airflow, the airflow is induced to flow towards the outlets, the lateral flow is reduced, the risk of developing into secondary flow and even back flow is reduced, the integral acting capacity of the impeller is improved, the air quantity and efficiency can be improved under the condition that the size or the rotating speed is unchanged, and the noise is reduced.

Description

Centrifugal fan and range hood with same

Technical Field

The invention relates to a power device, in particular to a centrifugal fan and a range hood using the centrifugal fan.

Background

The multi-wing centrifugal fan has the characteristics of high pressure, low noise and the like, so that a multi-wing centrifugal fan system is commonly used as a power source in the society at present, and the two functions of acting and filtering are completed in a volute by utilizing an impeller rotating at high speed. The multi-wing centrifugal fan comprises a volute, an impeller arranged in the volute and a motor for driving the impeller to rotate, when the impeller rotates, negative pressure suction is generated at the center of the fan, oil smoke below the range hood is sucked into the fan, and is collected and guided by the volute to be discharged outdoors after being accelerated by the fan.

In the prior art, a multi-wing centrifugal fan for a range hood is close to a middle disc area (for single suction of a short axial dimension, the multi-wing centrifugal fan is close to a rear disc) and is used as a main working area, and referring to fig. 6 and 7, an arrow in fig. 6 shows a gas flow path, and as can be seen from the figure, because air inflow along an axial direction is uneven, pressure difference is easily caused in the axial direction after air flows out of an impeller channel, the pressure difference is easy to cause the air flow to form a large secondary flow vortex 100 in a volute, and even the air flow is developed to flow back to an inlet area towards a front disc area and a rear disc area, so that the overall pneumatic efficiency is reduced, noise is increased, the effective working blade segment is low in proportion, and the real effective working blade segment only occupies a small segment close to the middle disc.

The conventional solution for improving the air quantity often depends on the rotation speed improvement or the size increase, the rotation speed improvement causes the noise to be further increased, and the size increase further invades the space of the cabinet.

Disclosure of Invention

The first technical problem to be solved by the invention is to provide a centrifugal fan aiming at the defects existing in the prior art, so that secondary flow vortex at an impeller outlet is reduced, the whole working capacity of the impeller is improved, and noise is reduced.

The second technical problem to be solved by the invention is to provide the range hood with the centrifugal fan.

The technical scheme adopted by the invention for solving the first technical problem is as follows: a centrifugal fan comprising an impeller, wherein the impeller comprises a disc far away from an air inlet side and at least two blades, and the blades are fixed with the disc far away from the air inlet side; the method is characterized in that:

the centrifugal fan also comprises annular guide vanes which encircle the outlets of the blades and extend outwards along the radial direction of the centrifugal fan from the fixing positions of the guide vanes and the blades;

along the axial direction of the centrifugal fan, on the same side of the disc far away from the air inlet side, the guide vanes are at least two arranged at intervals along the axial direction, and the height of the guide vanes gradually increases along with the increase of the distance from the disc far away from the air inlet side.

Through setting up a series of guide vanes of not co-altitude size at blade export interval, the height of guide vane and the inhomogeneous matching of axial air current, induced air current flows to the export, reduces the lateral flow, reduces the risk of developing into secondary stream, even backward flow, promotes impeller holistic acting capacity, can promote amount of wind and efficiency under the unchangeable circumstances of size or rotational speed, noise reduction.

Preferably, along the axial direction of the centrifugal fan, on the same side of the disk far away from the air inlet side, the height difference between any two adjacent guide vanes is delta H, and the delta H is formed by

Determining that the value range of beta is [0.2 DEG, 25 DEG ]]L is the spacing between the two adjacent baffles.

Preferably, the height of the guide vane is H, the outer diameter of the impeller is D2, and the range of the value of H to D2 is 0.02,0.08. Too small H can result in poor installation of the deflector, too large frictional resistance and interference with the volute tongue on the volute.

For further adapting the axial uneven air flow to guide the air flow to the air outlet, the secondary flow is reduced, along the axial direction of the centrifugal fan, on the same side of the disk far away from the air inlet side, the guide vanes are at least three arranged at intervals along the axial direction, and the distance between every two adjacent guide vanes gradually decreases along with the increase of the distance from the disk far away from the air inlet side.

Preferably, in the axial direction of the centrifugal fan, in any three guide vanes which are sequentially arranged on the same side of the disc far away from the air inlet side, the distance between every two adjacent guide vanes is L1 and L2 respectively, and the value range of L2/L1 is [0.6,1 ].

Further, through holes are formed in the guide plates, and the through holes penetrate through the two axial sides of the guide plates. The through holes can play a role of vortex, enhance the flow guiding effect on the area far away from the main flow, and utilize the vortex generated by the through holes and the energy of the boundary layer near the flow guiding sheet to ensure that the air flow better maintains the original direction after flowing out of the flow guiding sheet, thereby further reducing the subsequent deflection and the friction loss between the air flow and the flow guiding sheet.

Preferably, the distance between the center of the through hole and the outer edge of the guide vane is H, the height of the guide vane is H, and the value range of H/H is [0.1,0.6].

Preferably, the impeller has an outer diameter D2, and the ratio of the distance between any two adjacent guide vanes to D2 is within a range of [0.015,0.15] on the same side of the disk far from the air inlet side along the axial direction of the centrifugal fan. If the ratio is too low, the flow guide plate is too dense, the friction resistance is too high, the weight is increased, and the impeller efficiency is reduced; too high results in too sparse, and the flow guiding effect is weakened or not obvious.

Preferably, the centrifugal fan further comprises a volute, an air inlet is formed in the volute, and the impeller is a single-suction impeller or a double-suction impeller;

when the impeller is a single suction impeller, the number of the air inlets is one, the impeller comprises a front disc and a rear disc, the blades are respectively fixed with the front disc and the rear disc, the front disc is close to the air inlets, and the disc far away from the air inlets is the rear disc;

when the impeller is a double-suction impeller, the number of the air inlets is two, the impeller comprises a front disc, a middle disc and a rear disc, the blades are respectively fixed with the front disc, the middle disc and the rear disc, the front disc and the rear disc are respectively close to one of the air inlets, and the disc far away from the air inlet side is the middle disc.

Preferably, the flow deflector is mainly used for air flow outside the main acting area, the flow deflector is arranged outside a main flow area at the outlet of the blade, the main flow area is positioned adjacent to the disc far away from the air inlet side, and the value range of the ratio of the axial height of the main flow area to the axial height of the impeller is [0.1,0.5] along the axial direction of the centrifugal fan.

The invention solves the second technical problem by adopting the technical proposal that: a range hood, characterized in that: the centrifugal fan as described above is applied.

Compared with the prior art, the invention has the advantages that: through arranging a series of guide vanes with different height and size at intervals at the outlets of the blades, the height of the guide vanes is unevenly matched with the axial airflow, the airflow is induced to flow towards the outlets, the lateral flow is reduced, the risk of developing into secondary flow and even back flow is reduced, the integral acting capacity of the impeller is improved, the air quantity and efficiency can be improved under the condition that the size or the rotating speed is unchanged, and the noise is reduced; the flow guide plates are arranged at variable intervals, so that the axial uneven air flow can be further adapted to guide the air flow to the air outlet to flow, and secondary flow is reduced; the through holes are formed in the guide vane, the guide effect on the guide vane far away from the main flow area is enhanced, and vortex generated by the through holes and energy of a boundary layer near the guide vane are utilized, so that the original direction of airflow is better maintained after the airflow flows out of the guide vane, and the subsequent deflection and friction loss between the airflow and the guide vane are further reduced.

Drawings

FIG. 1 is a cross-sectional view of a centrifugal fan according to an embodiment of the invention;

FIG. 2 is an enlarged schematic view of part I of FIG. 1;

FIG. 3 is an enlarged schematic view of part II of FIG. 1;

FIG. 4 is a schematic diagram of a centrifugal fan hiding volute and motor (double suction impeller) of an embodiment of the present invention;

FIG. 5 is a schematic view of a centrifugal fan hiding volute and motor (single suction impeller) of an embodiment of the present invention;

FIG. 6 is a cross-sectional view of a centrifugal fan of the prior art;

fig. 7 is a flow field simulation schematic diagram of a centrifugal fan of the prior art.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for purposes of describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and because the disclosed embodiments of the present invention may be arranged in different orientations, these directional terms are merely for illustration and should not be construed as limitations, such as "upper", "lower" are not necessarily limited to orientations opposite or coincident with the direction of gravity. Furthermore, features defining "first", "second" may include one or more such features, either explicitly or implicitly.

Referring to fig. 1 to 4, a centrifugal fan includes a scroll 1, an impeller 2 disposed in the scroll 1, and a motor 3 for driving the impeller 2 to rotate. The volute 1 comprises two cover plates 11 which are arranged at intervals, an annular wall 12 which is formed between the cover plates 11, and an air inlet 13 is formed in the cover plates 11.

The impeller 2 comprises a front disc 21, a rear disc 22, a middle disc 23 and blades 24, wherein the middle disc 23 and the blades 24 are arranged between the front disc 21 and the rear disc 22, the two cover plates 11 are provided with air inlets 13, and the front disc 21 and the rear disc 22 are close to the corresponding air inlets 13. The blades 24 extend in the axial direction of the centrifugal fan, pass through the front plate 21, the middle plate 23, and the rear plate 22 described above, and are fixed to the front plate 21, the middle plate 23, and the rear plate 22, respectively. The number of the blades 24 is not less than 2, preferably about 60, to form a double suction impeller, and the centrifugal fan is a double air inlet fan. The impeller 2 alternatively does not comprise a middle disc 23 and forms a single suction impeller, see fig. 5, wherein only one cover plate 11 is provided with an air inlet 13, the front disc 21 is close to the air inlet 13, and the rear disc 22 is far away from the air inlet 13. The above structure is the same as that of the centrifugal fan in the prior art, and will not be described here again.

The centrifugal fan further comprises a guide vane 4, wherein the guide vane 4 is annular and is arranged at the outlet of each blade 24 (the outlet is the outer edge of the blade 24). The guide vanes 4 may have one or at least two, and when there are at least two, the guide vanes 4 are arranged at intervals along the axial direction of the centrifugal fan. Since the axial non-uniformity of the air flow in the main flow area is not obvious, the flow deflector 4 is preferably arranged outside the main flow area of the outlet of the blades 24 of the impeller 2, so that the cost can be reduced, and the main flow area is defined by the following modes: the main flow area is positioned at the position adjacent to the disc far away from the air inlet side, and the axial height of the main flow area is relative to the axial height of the impeller 2 along the axial direction of the centrifugal fan, and the ratio of the main flow area to the impeller 2 is [0.1,0.5]. When the impeller 2 is a single suction impeller, the disk far from the air intake side is the rear disk 22, and the main flow area is located between the rear disk 22 and the front disk 21 and extends from the rear disk 22 to the front disk 21, and the baffle 4 is disposed between the front disk 21 and the rear disk 22; when the impeller 2 is a double suction impeller, the disk far from the air intake side is a middle disk 23, and the main flow area is located at two axial sides of the middle disk 23, so that the overall axial height is kept as described above, and the ratio of two sides of the middle disk 23 is not strictly limited, and the flow guide 4 is arranged between the front disk 21 and the middle disk 23 and between the rear disk 22 and the middle disk 23. Of course, the guide vane 4 may be provided in the main flow region.

In the following, a double air intake fan is taken as an example, and a single air intake fan is similar to the double air intake fan, and the middle plate 23 is replaced by the rear plate 22. For easy processing and installation, the guide vane 4 and the vane 24 can be fixed by clamping, welding, bonding and the like, and the fixing part of the guide vane and the vane 24 extends outwards along the radial direction of the impeller 2. Along the axial direction of the centrifugal fan, on the same side of the middle disc 23 (i.e. between the front disc 21 and the middle disc 23 or between the middle disc 23 and the rear disc 22, hereinafter the same meaning is the same), the distance between adjacent guide vanes 4 gradually decreases with the gradual distance from the main flow area, i.e. the guide vanes 4 gradually encrypt, increasing the guide effect. Preferably, on the same side of the middle disc 23, three guide vanes 4 are arranged in any order, the spacing between two adjacent guide vanes 4 is respectively L1 and L2, wherein L1 is the spacing between the guide vane 4 closest to the middle disc 23 and the middle guide vane 4, and L2 is the spacing between the middle guide vane 4 and the guide vane 4 farthest from the middle disc 23, and the axial change rule is as follows: the value range of L2/L1 is [0.6,1 ].

The outer diameter of the impeller 2 is recorded as D2, the ratio value range of the interval between two adjacent guide vanes 4 and D2 on the same side of the middle disc 23 is selected as [0.015,0.15], the impeller is too dense if too low, the friction resistance of the guide vanes 4 is too large, and the weight is increased, so that the efficiency of the impeller 2 is reduced; too high results in too sparse, and the flow guiding effect is weakened or not obvious.

The height of the guide vane 4 is H, and the range of the value of H to D2 is [0.02,0.08]]Too small H can result in poor installation of the baffle 4, too large frictional resistance and interference with the volute tongue on the volute 1. The height is defined here as the height of the cross section of the deflector 4 in the radial direction of the centrifugal fan, which cross section is a section through the axis of the centrifugal fan and perpendicular to the radial plane of the centrifugal fan, as shown in fig. 1 as the plane of the paper. As can be seen from fig. 2 or 3, the deflector 4 has a shape of a sheet of uniform thickness and a substantially rectangular cross section. On the same side of the middle disc 23, the height difference between any two adjacent guide vanes 4 is deltah, wherein the height of the guide vane 4 close to the middle disc 23 is smaller than the height of the guide vane 4 far from the middle disc 23, according to

Obtaining delta H, wherein the value range of beta is [0.2 DEG, 25 DEG ]]L is the distance between any two adjacent baffles 4.

The guide vane 4 is provided with through holes 41, the through holes 41 are preferably cylindrical, the diameter range is [1, 10] mm, and the through holes 41 are preferably provided with at least two groups and are arranged at intervals along the height direction of the guide vane 4. The ratio of the distance H of the center of the through hole 41 relative to the outer edge (the side away from the blades 24) of the deflector 4 to the height H of the deflector 4 ranges from [0.1,0.6].

Referring to fig. 3 again, the arrow indicates a gas flow path, the airflow flowing out from the vane 24 completes deflection adjustment after passing through the guide vane 4, through the through hole 41 formed on the guide vane 4, the vortex effect on the area far away (far away in radial direction) from the main flow is enhanced, and the vortex (shown by a circle in the figure) generated by the through hole 41 and the energy of the boundary layer near the guide vane 4 are utilized, so that the original direction of the airflow is better maintained after the airflow flows out of the guide vane 4, and the subsequent deflection and the friction loss between the airflow and the guide vane 4 are further reduced.

Claims

1. A centrifugal fan comprising an impeller (2), the impeller (2) comprising a disc remote from an air intake side and at least two blades (24), the blades (24) being fixed to the disc remote from the air intake side; the method is characterized in that:

the centrifugal fan further comprises annular guide vanes (4), wherein the guide vanes (4) encircle the outlet of each blade (24) and extend outwards along the radial direction of the centrifugal fan from the fixing position of the guide vanes with the blades (24);

along the axial direction of the centrifugal fan, on the same side of the disc far away from the air inlet side, the guide vanes (4) are at least two arranged at intervals along the axial direction, and the height of the guide vanes (4) is gradually increased along with the increase of the distance from the disc far away from the air inlet side.

2. The centrifugal fan according to claim 1, wherein: along the axial direction of the centrifugal fan, on the same side of the disk far away from the air inlet side, the height difference between any two adjacent guide vanes (4) is delta H, and the delta H is formed by

Determining that the value range of beta is [0.2 DEG, 25 DEG ]]L is the distance between the two adjacent guide vanes (4).

3. The centrifugal fan according to claim 1 or 2, wherein: the height of the guide vane (4) is H, the outer diameter of the impeller (2) is D2, and the range of the value of H to D2 is [0.02,0.08].

4. The centrifugal fan according to claim 1, wherein: along the axial direction of the centrifugal fan, on the same side of the disc far away from the air inlet side, the guide vanes (4) are at least three arranged at intervals along the axial direction, and the distance between every two adjacent guide vanes (4) gradually decreases along with the increase of the distance from the disc far away from the air inlet side.

5. The centrifugal fan according to claim 4, wherein: along the axial direction of the centrifugal fan, in the same side of the disc far away from the air inlet side, in any three guide sheets (4) which are sequentially arranged, the distance between every two adjacent guide sheets (4) is L1 and L2 respectively, and the value range of L2/L1 is [0.6,1 ].

6. The centrifugal fan according to claim 1 or 2, wherein: the guide vane (4) is provided with a through hole (41), and the through hole (41) penetrates through the two axial sides of the guide vane (4).

7. The centrifugal fan according to claim 6, wherein: the distance between the center of the through hole (41) and the outer edge of the guide vane (4) is H, the height of the guide vane (4) is H, and the value range of H/H is [0.1,0.6].

8. The centrifugal fan according to claim 1 or 2, wherein: the outer diameter of the impeller (2) is D2, and the value range of the ratio of the interval between any two adjacent guide vanes (4) and D2 is [0.015,0.15] on the same side of the disc far away from the air inlet side along the axial direction of the centrifugal fan.

9. The centrifugal fan according to claim 1 or 2, wherein: the centrifugal fan further comprises a volute (1), an air inlet (13) is formed in the volute (1), and the impeller (2) is a single-suction impeller or a double-suction impeller;

when the impeller (2) is a single suction impeller, the number of the air inlets (13) is one, the impeller (2) comprises a front disc (21) and a rear disc (22), the blades (24) are respectively fixed with the front disc (21) and the rear disc (22), the front disc (21) is close to the air inlets (13), and the disc far away from the air inlets is the rear disc (22);

when impeller (2) are double suction impeller, the quantity of air intake (13) is two, impeller (2) are including front disc (21), middle dish (23) and back dish (22), blade (24) are fixed with front disc (21), middle dish (23) and back dish (22) respectively, front disc (21) and back dish (22) are close to one of them air intake (13) respectively, keep away from the dish of air inlet side and be middle dish (23).

10. The centrifugal fan according to claim 9, wherein: the guide vane (4) is arranged outside a main flow area at the outlet of the vane (24), the main flow area is positioned adjacent to the disc far away from the air inlet side, and the value range of the ratio of the axial height of the main flow area to the axial height of the impeller (2) along the axial direction of the centrifugal fan is 0.1 and 0.5.

11. A range hood, characterized in that: use of a centrifugal fan according to any of claims 1-10.