CA3013253C

CA3013253C - Impeller fan blade angles

Info

Publication number: CA3013253C
Application number: CA3013253A
Authority: CA
Inventors: Xuefei LIANG; Yi Liu; Jiajie ZHOU; Zhongqun Mao; Yongding Zhu; Ge LIU
Original assignee: Ningbo Fotile Kitchen Ware Co Ltd
Current assignee: Ningbo Fotile Kitchen Ware Co Ltd
Priority date: 2016-02-01
Filing date: 2017-01-24
Publication date: 2020-12-01
Anticipated expiration: 2037-01-24
Also published as: CA3013253A1; CN107023509A; AU2017215225C1; AU2017215225B2; AU2017215225A1; WO2017133370A1; CN107023509B; US20190010955A1

Abstract

The present invention discloses an impeller for a fan consisting of blades, each having a top, bottom, outer edge, and inner edge; and a rear wheel disc with a surface, periphery surface, center, a first projection line of each outer edge projected on the peripheral surface and a second projection line of each inner edge projected on the peripheral surface. The outer edges are adjacent to the periphery surface and the inner edges are adjacent to the center. The angle between the first projection line of each outer edge projected on the peripheral surface and the peripheral surface's radial line is defined as a (-60°<=.alpha.<=60°). The angle between the second projection line of each inner edge projected on the peripheral surface and the peripheral surface's radial line is defined as .beta. (20°<=.beta.70°). The angle between a first connecting line connecting the outer edge and center and a second connecting line connecting the inner edge and center and is defined as .theta. (10°<=.theta.<=65°).

Description

IMPELLER FAN BLADE ANGLES
Field of the Invention [0001] The present invention relates to a fan, and in particular to an impeller for a fan and a fan using the same.
Description of the Prior Art

[0002] A fan is an important part of a range hood. An impeller for the fan realizes energy conversion, and the performance of the impeller directly influences the performance of the range hood. At present, conventional impellers for range hoods are usually formed by stamping flat plates which are then connected by buckling their two ends, and blades are generally machined into a circular arc in a uniform thickness. Since the rotation speed of the impeller generally exceeds 800 RPM, the actual fluid separation and reflux between blades is obvious.
Moreover, since the impeller functions to pre-whirl gas and the gas will gradually change its direction in the process of flowing into the impeller to change its direction by 90 , the simple consistence in angle of an inlet and an outlet is disadvantageous for the actual performance of the impeller. In order to improve the fan efficiency, many improvements have been made to the structure of the impeller. However, these improvements are still limited to the binary flow technology, so that the efficiency improvement of the fan is limited, and the technical level of ordinary binary impellers will significantly influence the performance of the fan. Therefore, the defects of the binary impellers cannot be fundamentally overcome at present.
In addition, if the structure of the impeller is not changed fundamentally, at the same air pressure, the overall structure of the fan is not compact enough and is relatively large in size.
Accordingly, it is necessary to further improve the structure of the existing impellers and fans.
Summary of the Invention

[0003] A first technical problem to be solved by the present invention is, in view of the prior art, to provide an impeller for a fan, which is novel in structure and good in aerodynamic performance.

[0004] A second technical problem to be solved by the present invention is, in view of the prior art, to provide a fan which is compact in structure and high in both fan efficiency and air pressure.
- I -

[0005] Certain embodiments can provide an impeller for a fan, comprising: a plurality of blades, each blade having a top, a bottom, an outer edge, and an inner edge; and a rear wheel disc with a surface, a periphery surface, and a center, the plurality of blades mounted on the rear wheel disc, a first projection line of each outer edge as projected on the peripheral surface of the rear wheel disc, a second projection line of each inner edge as projected on the peripheral surface of the rear wheel disc; wherein: the outer edge of each blade is placed adjacent to the periphery of the rear wheel disc and the inner edge of each blade is adjacent to a center of the rear wheel disc, the bottom of each blade stands on the surface of the rear wheel disc, and the plurality of blades are arranged one by one successively along a circumferential direction of the rear wheel disc; the outer edge of each blade is an air exit, and an angle a is defined between the first projection line of each outer edge projected on the peripheral surface of the rear wheel disc and a radial line of the peripheral surface of the rear wheel disc and satisfies the following condition: -60'<a<60';
the inner edge of each blade is an air intake, and an angle 13 is defined between the second projection line of each inner edge projected on the peripheral surface of the rear wheel disc and the radial line of the peripheral surface of the rear wheel disc and satisfies the following condition:
20 <13<70'; an angle 0 is defined between a first connecting line connecting the outer edge of a blade and the center of the rear wheel disc and a second connecting line connecting the inner edge of a blade and the center of the rear wheel disc and satisfies the following condition:
<0<65'; and a first vertical height (h1) of the top of each outer edge is less than a second vertical height (h2) of the top of each inner edge.

[0006] Preferably, the outer edge of each blade is disposed adjacent to the periphery of the rear wheel disc; the inner edge of each blade is slanted downwardly toward the center of the rear wheel disc; each blade has a bottom surface all of which are located in a same plane; and, each blade has a smooth top surface.

[0007] Preferably, a ratio of the first vertical height h 1 to the second vertical height h2 satisfies the following condition: 0.2<hl /h2<0.8.

[0008] In order to further improve the aerodynamic performance of the impeller, the angle a satisfies the following condition: -30'<a<30'; the angle 13 satisfies the following condition:
30 <13<60'; the angle 0 satisfies the following condition: 20 <0<45 ; and, the ratio of the first vertical height hl to the second vertical height h2 satisfies the following condition:
0.4<hl/h2<0.6.

[0009] According to the size of the impeller and different parameter ranges, the number of blades may be different. Preferably, the plurality of blades comprise 10 to 50 blades.

[0010] As a preferred solution of any one of the above solutions, the impeller for the fan further comprises a front cover covering the plurality of blades; a first arc segment and a second arc segment that are jointed with each other from inside to outside are formed at an intersection of the front cover with a meridian plane of a rotating shaft of the impeller; and, a ratio of the radius RI of the first arc segment to the radius R2 of the second arc segment satisfies the following condition: 0.1<R1/R2<0.6.

[0011] Further preferably, a linear segment, which is disposed on an outer side of the second arc segment and smoothly jointed with the second arc segment, is further formed at the intersection of the front cover with the meridian plane of the rotating shaft of the impeller; and, a ratio of the length L of the linear segment to the radius R2 of the second arc segment satisfies the following condition: 0.1<L/R2<0.4. By providing the linear segment, it is convenient for machining the front cover, and the formation of a boundary layer at an end wall of the front cover can also be controlled.

[0012] To solve the second technical problem, the A fan using the impeller for a fan, comprises a volute, a motor and a wind inlet ring; characterized in that, the impeller for the fan is disposed inside the volute; the rear wheel disc of the impeller for the fan is disposed on an output shaft of the motor, and the wind inlet ring is disposed at a wind inlet of the fan and fitted with a front cover of the impeller for the fan.

[0013] In order to improve the fan efficiency, a distance 8 between the rear wheel disc and the volute close to the rear wheel disc satisfies the following condition:
1 mm<6<10 mm.

[0014] In order to further improve the fan efficiency, the front cover is covered outside the wind inlet ring, and a vertical distance A between a front edge of the front cover and an outside wall of the wind inlet ring satisfies the following condition: 0.5 mm<A<5 mm.

[0015] Compared with the prior art, the present invention has the following advantages:
in the impeller for a fan, a plurality of blades are arranged one by one successively along a circumferential direction of a rear wheel disc; an angle defined between a projection line of the outer edge and the inner edge of a blade and the center of the rear wheel disc satisfies a certain parameter range; an angle defined between a first connecting line connecting the outer edge of a blade and the center of the rear wheel disc and a second connecting line connecting the inner edge of a blade and the center of the rear wheel disc and satisfies a certain parameter range; and, the inner edge of a blade is higher than the outer edge. The impeller for a fan is novel in structure and good in aerodynamic performance.
The fan using this impeller is compact in structure, small in size, high in both fan efficiency and air pressure. and large in gradient of the generated negative pressure. When the fan is applied to a range hood, the escape of oil smoke can be prevented effectively, and the oil smoke extraction rate of the range hood can be improved greatly.
Brief Description of the Drawings

[0016] Fig. 1 is a perspective view of an impeller for a fan according to Embodiment 1 of the present invention;

[0017] Fig. 2 is a top view of the impeller for a fan shown in Fig. 1;
[00] 8] Fig. 3 is a side view of the impeller for a fan shown in Fig. 1;
[0019] Fig. 4 is a schematic structure view of backward inclination of an air exit of each blade according to Embodiment 1 of the present invention;
[0020] Fig. 5 is a schematic structure view of forward inclination of the air exit of the each blade according to Embodiment 1 of the present invention;
[0021] Fig. 6 is a schematic view of the projection of an air intake of each blade on a meridian plane of the impeller according to Embodiment 1 of the present invention;
[0022] Fig. 7 is a sectional view of the impeller for a fan shown in Fig. 1;
[0023] Fig. 8 is another sectional view of the impeller for a fan shown in Fig. 1;
[0024] Fig. 9 is a schematic view of the projection of each blade on the meridian plane of the impeller according to Embodiment 1 of the present invention;
[0025] Fig. 10 is a perspective view of a fan using the impeller according to Embodiment 1 of the present invention;
[0026] Fig. 11 is an exploded view of the fan shown in Fig. 10;
[0027] Fig. 12 is a sectional view of the fan shown in Fig. 10; and [0028] Fig. 13 is as perspective view of an impeller for a fan according to Embodiment 2 of the present invention.
Detailed Description of the Preferred Embodiment [0029] To enable a further understanding of the present invention content of the invention herein, refer to the detailed description of the invention and the accompanying drawings below:
[0030] Fig. I - Fig. 3 show a preferred Embodiment 1 of an impeller for a fan according to the present invention. In this embodiment, the impeller for a fan is a closed impeller.
The impeller comprises a plurality of blades 2, each blade 2 has a top, a bottom, an outer edge 21, and an inner edge 22; a rear wheel disc 1 with a surface, a periphery, and a center, the plurality of blades mounted on the rear wheel disc 1, a first projection line being defined on the rear wheel disc 1 and by the outer edge 21 of each blade 2, a second projection line being defined on the rear wheel disc 1 and by the inner edge 22 of each blade 2; and a front cover 3 covering the plurality of blades 2. The plurality of blades 2 are disposed between the rear wheel disc 1 and the front cover 3. The bottom of each blade 2 stands on the surface of the rear wheel disc I.
[0031] In this embodiment, the plurality of blades 2 comprise 10 to 50 blades.
The bottom of each blade 2 stands on the surface of the rear wheel disc 1 and the plurality of blades 2 are arranged one by one successively along a circumferential direction of the rear wheel disc 1. The surface of the rear wheel disc 1 is of a planar structure, and each blade 2 has a bottom surface 23 all of which are located in a same plane. The outer edges 21 of each blade 2 disposed adjacent to the periphery of the rear wheel disc 1, that is, the outer edge 21 of each blade is not slanted inward or outward relative to the rear wheel disc 1, and the inner edge 22 of each blade 2 is slanted downwardly toward the center of the rear wheel disc 1.
[0032] The outer edge 21 of each blade 2 is an air exit, and an angle a is defined between the first projection line 21a of each outer edge 21 projecting on the peripheral surface of the rear wheel disc 1 and a radial line of the peripheral surface of the rear wheel disc 1 and satisfies the following condition: -60'<a<60 , preferably -30'<a<30 . The direction shown by the arrows in Figs. 4 and 5 is a direction of rotation of the impeller. As shown in Fig. 4, the angle a of the outer edge 21 is positive (from radial line la to projection line 21a); and, as shown in Fig. 5, the angle a of the outer edge 21 is negative (from radial line la to projection line 21a). In this embodiment, a=0 , that is, the angle of the air exit of each blade is 00. As shown in Fig. 6, the inner edge 22 of each blade 2 is an air intake, and an angle 13 is defined between the second projection line 22a of each inner edge 22 projected on the peripheral surface of the rear wheel disc 1 and the radial line of the peripheral surface of the rear wheel disc 1 and satisfies the following condition: 20 13<70 . In order to further improve the aerodynamic performance, the included angle p satisfies the following condition: 30 13.<60 . In addition, as shown in Fig. 7, an angle 0 is defined between a first connecting line LI connecting the outer edge of a blade and the center of the rear wheel disc I and a second connecting line L2 connecting the inner edge of a blade and the center of the rear wheel disc 1 and satisfies the following condition: 10 <0<65 , preferably 20 <0<45 .
[0033] As shown in Fig. 8, the front cover 3 is of a trumpet mouth structure which expands outward from the middle. Specifically, a first arc segment 31, a second arc segment 32 and a linear segment 33 that are smoothly jointed with each other from inside to outside are formed at an intersection of the front cover 3 with a meridian plane of a rotating shaft of the impeller. A
ratio of the radius R I of the first arc segment 31 to the radius R2 of the second arc segment 32 satisfies the following condition:
0.1<R1/R2<0.6;

and a ratio of the length L of the linear segment 33 to the radius R2 of the second arc segment 32 satisfies the following condition: 0.1<L/R2<0.4. After the above structural parameters are used in the front cover 3, the aerodynamic performance of the impeller may be better. In addition, by the linear segment 33, it is convenient for machining the front cover, and the formation of a boundary layer at an end wall of the front cover can also be controlled.
[0034] As shown in Fig. 8 and Fig. 9, a first vertical height hl of the top P1 of each outer edge 21 is less than a second vertical height h2 of the top P2 of each inner edge 22, and a ratio of the first vertical height hl to the second vertical height h2 satisfies the following condition: 0.2<h 1/h2<0.8, preferably 0.4<h1/h2<0.6. Furthermore, each blade 2 has a smooth top surface 24 which is sunken inward in its center, and the top surface 24 is between the top of the inner edges 22 and the top of the outer edges 21.
[0035] Fig. 10 - Fig. 12 show a preferred embodiment of a fan using the impeller for a fan according to Embodiment 1 of the present invention. In this embodiment, the fan comprises a volute 4, a motor 5 and a wind inlet ring 6. The impeller for the fan is disposed inside the volute 4. The rear wheel disc 1 of the impeller for the fan is disposed on an output shaft of the motor 5 and locked by a nut 7. The wind inlet ring 6 is disposed at a wind inlet of the fan. The front cover 3 is covered outside the wind inlet ring 6, and a wind outlet hood 8 is disposed at the wind outlet of the fan.
[0036] In order to improve the fan efficiency, in this embodiment, a distance 5 between the rear wheel disc 1 and a wall 41 close to the rear wheel disc 1 satisfies the following condition: 1 mm<o<10 mm; and, a vertical distance A between a front edge of the front cover 3 and an outside wall of the wind inlet ring 6 satisfies the following condition: 0.5 mm<4<5 mm. The tests show that the fan efficiency is maximized after the structural parameters of the fan are within the above numerical ranges.
[0037] Embodiment 2:
[0038] Fig. 13 shows Embodiment 2 of the impeller for a fan according to the present invention. In this embodiment, the impeller for a fan is an open impeller. The impeller comprises a rear wheel disc 1 and a plurality of blades 2. Compared with the impeller for a fan in Embodiment 1, in this impeller, the front cover is omitted. The remaining structure is the same as the structure in Embodiment 1 and will not be repeated here.
[0039] The foregoing description merely shows preferred embodiments of the present invention. It should be noted that various modifications or improvements may be made to the present invention by a person of ordinary skill in the art without departing from the principle of the present invention, for example, the blades of the impeller may be of a planar structure, and these modifications or improvements shall fall into the protection scope of the present invention.

Claims

1. An impeller for a fan, comprising:
a plurality of blades, each blade having a top, a bottom, an outer edge, and an inner edge; and a rear wheel disc with a surface, a periphery surface, and a center, the plurality of blades mounted on the rear wheel disc, a first projection line of each outer edge as projected on the peripheral surface of the rear wheel disc, a second projection line of each inner edge as projected on the peripheral surface of the rear wheel disc; wherein:
the outer edge of each blade is placed adjacent to the periphery surface of the rear wheel disc and the inner edge of each blade is adjacent to the center of the rear wheel disc, the bottom of each blade stands on the surface of the rear wheel disc, and the plurality of blades are arranged one by one successively along a circumferential direction of the rear wheel disc;
the outer edge of each blade is an air exit, and an angle .alpha. is defined between the first projection line of each outer edge projected on the peripheral surface of the rear wheel disc and a radial line of the peripheral surface of the rear wheel disc and satisfies the following condition: -60°<=.alpha.<=60°;
the inner edge of each blade is an air intake, and an angle .beta. is defined between the second projection line of each inner edge projected on the peripheral surface of the rear wheel disc and the radial line of the peripheral surface of the rear wheel disc and satisfies the following condition:
20°<=.beta.70°;
an angle .theta. is defined between a first connecting line connecting the outer edge of a blade and the center of the rear wheel disc and a second connecting line connecting the inner edge of a blade and the center of the rear wheel disc and satisfies the following condition:
10°<=.theta.<=65°; and a first vertical height of the top of each outer edge is less than a second vertical height of the top of each inner edge.

2. The impeller according to claim 1, wherein:
the outer edge of each blade is disposed adjacent to the periphery of the rear wheel disc ;
the inner edge of each blade is slanted downwardly toward the center of the rear wheel disc;
each blade has a bottom surface all of which are located in a same plane; and, each blade has a smooth top surface.

3. The impeller according to claim 1, wherein a ratio of the first vertical height to the second vertical height satisfies the following condition:
0.2<=h1/h2<=0.8.

4. The impeller according to claim 3, wherein:
the angle .alpha. satisfies the following condition: -30°<=.alpha.<=30°;

the angle .beta. satisfies the following condition:
30°<=.beta.<=60°;
the angle .theta. satisfies the following condition:
20°<=.theta.<=45°; and the ratio of the first vertical height to the second vertical height satisfies the following condition: 0.4<=h1/h2<=0.6.

5. The impeller according to claim 1, wherein the plurality of blades comprise 10 to 50 blades.

6. The impeller according to claim 1, further comprising:
a front cover covering the plurality of blades;
a first arc segment and a second arc segment that are jointed with each other from inside to outside are formed at an intersection of the front cover with a meridian plane of a rotating shaft of the impeller; and a ratio of the radius (R1) of the first arc segment to the radius (R2) of the second arc segment satisfies the following condition: 0.1<=R1/R2<=0.6.

7. The impeller according to claim 6, wherein:
a linear segment, which is disposed on an outer side of the second arc segment and smoothly jointed with the second arc segment, is formed at the intersection of the front cover with the meridian plane of the rotating shaft of the impeller; and, a ratio of the length (L) of the linear segment to the radius (R2) of the second arc segment satisfies the following condition: 0.1<=L/R2<=0.4.

8. A fan using the impeller according to claim 6, comprising a volute, a motor and a wind inlet ring, wherein:
the impeller for the fan is disposed inside the volute;
the rear wheel disc of the impeller for the fan is disposed on an output shaft of the motor; and the wind inlet ring is disposed at a wind inlet of the fan and fitted with a front cover of the impeller for the fan.

9. The fan according to claim 8, wherein a distance (.delta.) between the rear wheel disc and a wall of the volute close to the rear wheel disc satisfies the following condition:
1 mm<=.delta.<=10 mm.

10. The fan according to claim 8, wherein the front cover is covered outside the wind inlet ring, and a vertical distance (.DELTA.) between a front edge of the front cover and an outside wall of the wind inlet ring satisfies the following condition: 0.5 mm<=.DELTA.<=5 mm.