CN114893422A

CN114893422A - Fan and range hood

Info

Publication number: CN114893422A
Application number: CN202210446442.3A
Authority: CN
Inventors: 任富佳; 李智宝; 于巍巍; 常莹; 周海昕; 王嘉明; 余国成; 黄文才
Original assignee: Hangzhou Robam Appliances Co Ltd
Current assignee: Hangzhou Robam Appliances Co Ltd
Priority date: 2022-04-26
Filing date: 2022-04-26
Publication date: 2022-08-12

Abstract

The invention relates to the technical field of range hoods, and particularly discloses a fan and a range hood. The arrangement enables circumferentially uneven airflow flowing out of the blades to be dispersed on the volute tongue surface along the direction perpendicular to the output shaft, namely, the phase of the pulse airflow acting on the volute tongue surface is staggered, so that the pulse force generated on the volute tongue surface is reduced, and the noise of the fan is greatly reduced.

Description

Fan and range hood

Technical Field

The invention relates to the technical field of range hoods, in particular to a fan and a range hood.

Background

At present, along with the improvement of living standard of people, the range hood is gradually popularized in common families. In the continuous development of the range hood, the range hood not only needs to meet the smoking effect, but also needs to consider the noise problem in the smoking process.

The lampblack absorber includes the shell and locates the fan in the shell, and the power piece that the fan is connected including fixing the spiral case on the shell and rotating the impeller that sets up at the spiral case inside and with impeller transmission, and the impeller takes place to rotate under the effect of power piece, and can flow to the spiral case at the inhomogeneous air current that rotates the in-process and produce, flows out from the export of spiral case under the guide effect of spiral case, but current fan structure can produce great noise at the course of the work.

Disclosure of Invention

The invention aims to provide a fan and a range hood, and aims to solve the problem that the fan in the prior art has high noise in the working process.

In order to achieve the purpose, the invention adopts the following technical scheme:

in one aspect, the present invention provides a fan comprising:

a volute;

the power part is arranged in the volute;

the impeller, the impeller with the output transmission of power spare is connected, just the blade of impeller is followed the width direction of spiral case with the axial of the output shaft of power spare is the contained angle setting and out of plumb.

Preferably, the included angle between the blades and the axial direction of the output shaft of the power member is 12-16 degrees.

Preferably, the fan further comprises a transition section, and the transition section is arranged at the outlet of the volute.

Preferably, the volute comprises a volute front plate, a volute rear plate and a volute side plate, and the volute side plate is connected between the volute rear plate and the volute front plate; the vanes are inclined to the transition section in a direction from the volute back plate to the volute front plate.

Preferably, the transition section comprises a front curved surface, a left curved surface, a rear curved surface and a volute tongue surface which are sequentially connected, the lower ends of the front curved surface, the left curved surface, the rear curved surface and the volute tongue surface are all linear, and the front curved surface and the rear curved surface are respectively used for being connected with a volute front plate and a volute rear plate; the volute tongue surface and the left curved surface are respectively used for being connected with the starting end and the tail end of the volute side plate; and/or

The volute tongue surface of the transition section is positioned in the shell, the distance between the front volute plate and the rear volute plate is B, the distance between the front plate surface and the rear plate surface of the shell is C, C is not less than 1.5B, and the upper ends of the front curved surface, the left curved surface, the rear curved surface and the volute tongue surface are in four non-concentric arc shapes.

Preferably, the volute tongue surface is an inward concave surface close to the outlet of the volute, and the volute tongue surface is a plane close to the starting point of the volute.

Preferably, the plane of the volute tongue surface and the output shaft form an included angle and are not perpendicular.

Preferably, the included angle between the plane of the volute tongue surface and the axial direction of the output shaft is 12-16 degrees.

Preferably, the fan further comprises an air outlet section, an inlet of the air outlet section is communicated with an outlet of the transition section, the shape of the inlet of the air outlet section is the same as that of the outlet of the transition section, and the shape of the outlet of the air outlet section is circular

On the other hand, the invention provides a range hood, which comprises a shell and the fan in any technical scheme.

The beneficial effects of the invention are as follows:

the invention provides a fan, namely a range hood, which comprises a volute, a power part and an impeller, wherein the power part is arranged in the volute, the impeller is in transmission connection with the output end of the power part, and blades of the impeller are arranged along the width direction of the volute and form an included angle with the axial direction of an output shaft of the power part and are not vertical. The arrangement enables circumferentially uneven airflow flowing out of the blades to be dispersed on the volute tongue surface along the direction perpendicular to the output shaft, namely, the phase of the pulse airflow acting on the volute tongue surface is staggered, so that the pulse force generated on the volute tongue surface is reduced, and the noise of the fan is greatly reduced.

Drawings

FIG. 1 is a schematic structural diagram of a range hood in an embodiment of the invention;

FIG. 2 is a schematic structural diagram of a blower in an embodiment of the present invention;

FIG. 3 is an exploded view of the blower of the embodiment of the present invention;

FIG. 4 is a schematic diagram of a spiral configuration for forming a volute in an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a transition section in an embodiment of the present invention;

FIG. 6 is a schematic view of a blade according to an embodiment of the present invention;

FIG. 7 is a schematic top view of a transition section in an embodiment of the present invention;

FIG. 8 is a first perspective view of the tongue surface of the volute of the present invention;

FIG. 9 is a second perspective view of the tongue surface of the volute of the present invention;

FIG. 10 is a schematic top view of a blower according to an embodiment of the present invention;

FIG. 11 is a schematic side view of a fan according to an embodiment of the present invention;

fig. 12 is a schematic front view of a fan according to an embodiment of the present invention.

In the figure:

100. a housing; 200. a power member; 300. an impeller; 301. a blade;

1. a volute front plate; 2. a volute back plate; 3. a volute side plate;

s1, a first volute curve; s2, a second volute curve; l1, volute straight line; s3, a third volute curve; s4, a fourth volute curve; s5, transition outer contour arcs; s6, a first outer contour arc line; s7, a second outer contour arc; s8, volute tongue profile arc;

4. a transition section; 41. a front curved surface; 411. a front first face; 412. a front second face; 413. a front third face; 42. a left curved surface; 43. a back curved surface; 44. snail tongue surface;

5. an air outlet section; 51. a first curved surface; 52. a second curved surface; 53. a third curved surface; 54. a fourth curved surface; 501. and (4) clustering curves.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Where the terms "first position" and "second position" are two different positions, and where a first feature is "over", "above" and "on" a second feature, it is intended that the first feature is directly over and obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

Example one

As shown in fig. 1 to 12, the present embodiment provides a scroll casing including a scroll casing rear plate 2, a scroll casing front plate 1, and a scroll casing side plate 3, the scroll casing side plate 3 being connected between the scroll casing rear plate 2 and the scroll casing front plate 1. The inner side wall of the volute side plate 3 is formed by sequentially connecting a first volute curve S1, a second volute curve S2, a volute straight line L1, a third volute curve S3 and a fourth volute curve S4, the opening degrees of the volutes at the first volute curve S1, the second volute curve S2, the third volute curve S3 and the fourth volute curve S4 are gradually increased along the outlet direction, the volute straight line L1 is a horizontal line of the bottom of the volute, and the opening degree of the volute at the volute straight line L1 is kept constant along the outlet direction. In the volute, as the volute curve is gradually increased along the outlet direction of the volute as a whole, the opening degree of the volute at the bottom of the volute is far larger than the outer diameter of the impeller 300, and only the volute straight line L1 arranged at the bottom of the volute does not influence the outer diameter of the impeller 300, so that the arrangement does not need to reduce the outer diameter of the impeller 300 on the basis of reducing the height H of the whole volute, and the volute does not cause the power reduction of the impeller 300 on the basis of adapting to the casing 100 with a slightly smaller height. Compared with the scheme of reducing the overall size of the volute and further reducing the outer diameter of the impeller 300 in the prior art, the arrangement of the embodiment is beneficial to improving the power of the impeller 300 when the rotating speed is the same, and is beneficial to reducing noise when the power is the same.

With respect to the specific structure of the first volute curve S1, optionally, the first volute curve S1 is represented by the equation

Determining; wherein the angle range of the first volute curve S1 is 38-205 degrees, D is the outer diameter of the impeller 300, e is the natural number base number, t1 is a curve control parameter, t1 is more than 0 and less than or equal to 0.1,

is the angle between the connecting line of the point on the first volute curve S1 and the center O and the initial ray. The equation is simpler, and the adjustment is more flexible and convenient.

With respect to the specific structure of the fourth volute curve S4, optionally, the fourth volute curve S4 is represented by the equation

Determining; wherein the angle range of the curve S4 of the fourth volute is 265-360 degrees, D is the outer diameter of the impeller 300, e is the natural number base number, t2 is a curve control parameter, t2 is more than 0 and less than or equal to 0.1,

is the angle between the connecting line of the point on the second volute curve S2 and the center O and the initial ray. The equation is simpler, and the adjustment is more flexible and convenient.

Regarding the opening degree of the volute at each place, in the present embodiment, preferably, the opening degree of the volute at the first volute curve S1 is

The opening degree of the volute at the curve S4 of the fourth volute is

Wherein t2 is more than or equal to t 1. Preferably, t1 is t1 ═ 0.0439, and t2 is t1 ═ 0.0445. Of course, in other embodiments, t1 and t2 may be other values, and in particular, may be determined according to the height dimension of the housing 100. The spiral line of the volute can be widened close to the outlet side by the arrangement, and the area of the air exhaust channel is increased. The matching of the equations can realize the change of the opening degree of the volute on one hand, and divide the spiral line of the volute into five pieces, thereby realizing the segmented control and being easier to adjust; the first volute curve S1 is facilitated to be perpendicular to the line between the point and the circle center 0 at 205 degrees, the fourth volute curve S4 is facilitated to be perpendicular to the line between the point and the circle center 0 at 265 degrees, drawing of the second volute curve S2 and the third volute curve S3 is facilitated, the second volute curve S2 and the third volute curve S3 are tangent to the first volute curve S1 and the fourth volute curve S4 respectively, and integral sudden change is reduced.

In order to achieve smooth connection of the volute, in the present embodiment, preferably, the second volute curve S2 is a circular arc, and two ends of the second volute curve S2 are tangent to the first volute curve S1 and the volute straight line L1 respectively. The third volute curve S3 is a circular arc, and both ends are tangent to the fourth volute curve S4 and the volute straight line L1. Of course, in other embodiments, an elliptical arc may be used for the connection, and the connection is not limited to this.

Example two

The present embodiment further provides a blower, which includes a transition section 4 and the volute casing in any of the above embodiments, wherein the transition section 4 is disposed at an outlet of the volute casing. The volute of the fan is also provided with a power part 200 and an impeller 300, the power part 200 is preferably a motor, wherein the impeller 300 is in transmission connection with the output end of the motor fixed on the casing 100. By means of the structure of the volute, the fan can adapt to the shell 100 with a slightly lower height, the working efficiency of the impeller 300 cannot be reduced, and the noise in the air duct cannot be increased.

Specifically, the transition section 4 comprises a front curved surface 41, a left curved surface 42, a rear curved surface 43 and a volute tongue surface 44 which are connected in sequence, the lower ends of the front curved surface 41, the left curved surface 42, the rear curved surface 43 and the volute tongue surface 44 are all linear, and the front curved surface 41 and the rear curved surface 43 are respectively used for being connected with the volute front plate 1 and the volute rear plate 2; the volute tongue surface 44 and the left curved surface 42 are respectively used for connecting with the starting end and the tail end of the volute side plate 3; and/or

The volute tongue surface 44 of the transition section 4 is positioned in the shell 100, the distance between the volute front plate 1 and the volute rear plate 2 is B, the distance between the front plate surface and the rear plate surface of the shell 100 is C, C is not less than 1.5B, and the upper ends of the front curved surface 41, the left curved surface 42, the rear curved surface 43 and the volute tongue surface 44 are in four non-concentric arc shapes. Wherein, B is more than or equal to 90mm and less than or equal to 120mm, and C is 180 mm. Because of the limitation of the height of the shell 100, the width dimension of the outlet of the volute and the diameter dimension of the outlet of the transition section 4 are ensured to be in smooth transition, and the transition section 4 cannot be in a circular shape in the shell 100 to avoid sudden change caused by a flow channel.

The maximum distance W1 between the two arcs at the upper ends of the front curved surface 41 and the rear curved surface 43 is more than or equal to the opening degree A2 of the fourth volute curve S4 at the position of 360 degrees,

in this example t2 is 0.0445,

the radian of the left curved surface 42 extends along the volute side plate 3 formed by the fourth volute curve S4, and the maximum distance W2 between the arc formed by the upper end of the left curved surface 42 and the arc formed by the upper end of the volute tongue surface 44 is close to W1. The purpose of the transition end is to enable a quadrangle at the end section of the side face of the volute to be in a nearly circular arc connection structure, ensure that the sizes of the diffusion sections are close, and prevent sudden change loss.

The volute tongue surface 44 is enclosed based on a Bezier curve, an outlet of the volute tongue surface 44, which is close to the volute, is of an inward concave surface structure, a starting point of the volute is of a plane structure, the outlet of the volute is 360 degrees, namely 0 degree, and the starting point of the volute is 38 degrees. The upper part and the lower part of the volute tongue surface 44 at the concave surface structure are closer to the impeller 300, which is beneficial to improving outlet static pressure and fan efficiency, the air flow speed at the middle part of the impeller 300 is higher, and the concave surface structure can reduce flow resistance and eliminate outlet eddy.

Specifically, the two-dimensional curve type line equation of the volute tongue surface 44 is as follows,

the expression may be expressed as a bezier curve n times to change the shape of the curve by changing the position of the control points, where P is the control point coordinates and n is the number of control points. The shape of the Bezier curve can be changed by changing the position of the control point, the curve generation mode is more intuitive and flexible, and any curve shape can be generated.

First column number: n-4, P0-28.5, P1-43.4, P2-47.6, P3-51.7, P4-42.8, i.e.

The second column count: n-4, P0-151.6, P1-146.0, P2-144.7, P3-154.4, P4-167.9, i.e.:

the first column number represents the coordinates of all X-axis vectors corresponding to the curve, and t is any number within the range of 0-1. The second column number represents the coordinates of all the corresponding Y-axis vectors on the curve, and t is any number within the range of 0-1. The positions of all points on the spline curve can be represented by B1(t) and B2(t), and the shape and size parameters of the curve are determined.

In this embodiment, the impeller 300 includes a vane 301 and an output shaft, and the vane 301 is disposed along the width direction of the volute and forms an included angle with the output shaft, and is not perpendicular. As shown in fig. 2, the width direction of the volute is the direction from the volute front plate 1 to the volute back plate 2 or from the volute back plate 2 to the volute front plate 1. Wherein the included angle theta can be any degree between 12 degrees and 16 degrees. The arrangement enables the circumferential uneven airflow flowing out of the blades 301 to be dispersed on the volute tongue surface 44 along the direction perpendicular to the output shaft, namely the phase of the pulse airflow acting on the volute tongue surface 44 is staggered, and further the pulse force generated on the volute tongue surface 44 is reduced, so that the noise of the fan is greatly reduced.

Preferably, the vanes 301 are inclined to the transition section 4 in the direction of the volute back plate 2 to the volute front plate 1. This arrangement facilitates the transport of the air flow towards the volute front plate 1 and thus adapts to the configuration where the exit end of the transition section 4 is located in front of the volute back plate 2.

Optionally, the plane of the lower end of the volute tongue face 44 is disposed at an angle to the output shaft. The arrangement can disperse the airflow flowing out of the blades 301 on the volute tongue surface 44 along the axial direction of the output shaft, further reduce the pulse force generated on the volute tongue surface 44, and further reduce the noise of the range hood. Optionally, the angle between the straight line at the lower end of the volute tongue face 44 and the output shaft is the same as the angle between the blade 301 and the shaft. I.e. the angle between the plane of the volute tongue surface 44 and the axial direction of the output shaft is 12-16 deg..

Regarding the arrangement of the transition section 4, in this embodiment, the front curved surface 41 protrudes forward from the front plate 1 of the volute, the horizontal distance between the arc line formed by the upper end of the front curved surface 41 and the front plate 1 of the volute is greater than 0, the rear curved surface 43 protrudes forward from the rear plate 2 of the volute, and the horizontal distance between the arc line formed by the upper end of the rear curved surface 43 and the rear plate 2 of the volute is greater than or equal to 0; both the left curved surface 42 and the volute tongue surface 44 are inclined in a direction towards the volute front plate 1. The above construction results in the projection of the exit of the transition section 4 in the horizontal plane being located in front of the projection of the volute backplate 2 in the horizontal plane. And then will be equipped with the lampblack absorber of this spiral case and install behind the wall, do not interfere between changeover portion 4 and the wall.

Specifically, the front curved surface 41 includes a front first surface 411, a front second surface 412 and a front third surface 413 which are sequentially connected from left to right, wherein the front first surface 411 protrudes forwards from the volute front plate 1, a horizontal distance between an arc line formed at the upper end of the front first surface 411 and the volute front plate 1 is greater than 0, the rear curved surface 43 includes a rear first surface, a rear second surface and a rear third surface which are sequentially connected from left to right, wherein the rear first surface protrudes forwards from the volute rear plate 2, and the horizontal distance between the arc line formed at the upper end of the rear first surface and the volute rear plate 2 is greater than or equal to 0. The lower ends of the front second surface and the rear second surface are respectively connected to the tail ends, close to the volute side plate 3, of the volute front plate 1 and the volute rear plate 2; the upper ends of the front second surface and the rear second surface are respectively connected with the front side edge and the rear side edge of the snail tongue surface 44; the upper ends of the front third surface and the rear third surface are respectively connected to the initial ends of the volute front plate 1 and the volute rear plate 2 close to the volute side plate 3.

The oil smoke needs to be transmitted continuously after coming out of the transition section 4, in this embodiment, preferably, the fan further includes an air outlet section 5, the fan further includes the air outlet section 5, an inlet of the air outlet section 5 is communicated with an outlet of the transition section 4, an inlet shape of the air outlet section 5 is the same as an outlet shape of the transition section 4, and an outlet shape of the air outlet section 5 is circular. Specifically, the air outlet section 5 includes a first curved surface 51, a second curved surface 52, a third curved surface 53 and a fourth curved surface 54 which are connected in sequence, the first curved surface 51, the second curved surface 52, the third curved surface 53 and the fourth curved surface 54 are four non-concentric arcs at the lower end of the air outlet section 5, and the first curved surface 51, the second curved surface 52, the third curved surface 53 and the fourth curved surface 54 are four concentric arcs at the upper end of the air outlet section 5. In the arrangement, the air outlet section 5 is in a circular shape in a smooth transition from the inlet to the outlet, so that the air outlet section can be smoothly connected into a circular smoke exhaust pipe, the circulation resistance is reduced, and the loss of airflow in the volute caused by curvature mutation is reduced.

Preferably, the smooth transition of the air outlet section 5 from the inlet to the outlet is realized by a control curve cluster 501, wherein in computer graphics, the dimensional relationship in the space of the curve cannot be controlled only by constructing a spline curve by side lines, the curve cluster 501 is a series of circular arcs, the space curve cluster 501 which is uniform in density and gradually transits is formed in space according to a certain contour control line, and the space curve cluster 501 is scanned by a plane to form a smooth-transiting and full flow channel space.

The first outer contour arc line S6 of the curve cluster 501 is a concave arc line, and is smoothly connected with the transition outer contour arc line S5 of the transition section 4, so that premature flow separation of air flow is inhibited, the speed reduction and pressurization of the air flow at the outlet of the air outlet section 5 can be realized, premature flow separation of air from the wall surface of the air outlet section 5 is inhibited, and pneumatic noise is reduced.

And a second outer contour arc S7 of the curve cluster 501 is an outward convex arc which is smoothly connected with the volute tongue contour arc S8 of the volute tongue surface 44 and plays a role in gathering air flow.

Based on the combined action of the first outer contour arc S6 and the second outer contour arc S7, the airflow transition is smooth, the airflow is released first and then received, the airflow separation noise is reduced, and the sudden change loss of a larger shape is avoided. The outlet airflow of the air outlet section 5 can be uniformly distributed, and the problems of large-scale vortex and flow dead zones existing in the outlet area of the air outlet section 5 are solved.

Optionally, the distance between the circular shape O of the upper end of the air outlet section 5 and the bottom plate of the volute is L2, the distance between the front plate 1 of the volute and the rear plate 2 of the volute is B, and B/2 < L2 < B. This setting can guarantee to be equipped with the lampblack absorber of this spiral case and install behind the wall, does not interfere between air outlet section 5 and the wall.

EXAMPLE III

The embodiment also provides a range hood, which comprises a shell 100 and a fan arranged in the shell 100, wherein the fan is arranged in the shell 100.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A fan, comprising:

a volute;

the power piece (200), the said power piece (200) locates in the said spiral case;

the impeller (300), impeller (300) with the output transmission of power spare (200) is connected, just blade (301) of impeller (300) are followed the width direction of spiral case with the axial of the output shaft of power spare (200) is the setting of contained angle and is out of plumb.

2. The fan according to claim 1, wherein the angle between the blades (301) and the axial direction of the output shaft of the power member (200) is 12-16 °.

3. The fan according to claim 2, further comprising a transition section (4), the transition section (4) being provided at an outlet of the volute.

4. The fan according to claim 3, wherein the volute comprises a volute front plate (1), a volute back plate (2) and a volute side plate (3), the volute side plate (3) being connected between the volute back plate (2) and the volute front plate (1); the vanes (301) are inclined to the transition section (4) in the direction from the volute back plate (2) to the volute front plate (1).

5. The fan according to claim 4, wherein the transition section (4) comprises a front curved surface (41), a left curved surface (42), a rear curved surface (43) and a volute tongue surface (44) which are connected in sequence, the lower ends of the front curved surface (41), the left curved surface (42), the rear curved surface (43) and the volute tongue surface (44) are all linear, and the front curved surface (41) and the rear curved surface (43) are respectively used for being connected with the volute front plate (1) and the volute rear plate (2); the volute tongue surface (44) and the left curved surface (42) are respectively used for being connected with the starting end and the tail end of the volute side plate (3); and/or

The volute tongue surface (44) of the transition section (4) is located in the shell, the distance between the volute front plate (1) and the volute rear plate (2) is B, the distance between the front plate surface and the rear plate surface of the shell is C, the C is larger than or equal to 1.5B, and the upper ends of the front curved surface (41), the left curved surface (42), the rear curved surface (43) and the volute tongue surface (44) are in four non-concentric arc shapes.

6. The fan of claim 5 wherein the volute tongue surface (44) is concave adjacent the outlet of the volute and the volute tongue surface (44) is flat adjacent the start of the volute.

7. The fan of claim 6 wherein the plane of the volute tongue surface (44) is disposed at an angle to the output shaft that is not perpendicular.

8. The fan of claim 7 wherein the angle between the plane of the volute tongue surface (44) and the axial direction of the output shaft is between 12 ° and 16 °.

9. The fan according to claim 5, further comprising an outlet section (5), wherein an inlet of the outlet section (5) is in communication with an outlet of the transition section (4), wherein an inlet shape of the outlet section (5) is the same as an outlet shape of the transition section (4), and wherein an outlet shape of the outlet section (5) is circular.

10. A range hood comprising a housing (100), characterized in that it further comprises a fan according to any of claims 1-9.