CN111878424B

CN111878424B - Large air volume volute fan

Info

Publication number: CN111878424B
Application number: CN202010866342.7A
Authority: CN
Inventors: 刘奕; 杨士豹
Original assignee: Zhongshan Gaotu Hardware Products Co ltd
Current assignee: Zhongshan Gaotu Hardware Products Co ltd
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2024-05-17
Anticipated expiration: 2040-08-25
Also published as: CN111878424A

Abstract

The invention relates to a large-air-volume spiral case fan which comprises a spiral case, a wind wheel and a motor, wherein an air channel is formed in the spiral case, a coaming of the spiral case is in an open ring shape, an air outlet is formed in an opening of the coaming, the wind wheel is arranged in the air channel and is in transmission connection with the motor, a first extraction plate and a second extraction plate are respectively arranged on two sides of the air outlet, the second extraction plate is connected with the other end of the opening of the coaming through an arc transition surface, the horizontal distance from the tangent point of the arc transition surface and a vertical line to the first extraction plate is 125-155mm, and an included angle between the second extraction plate and the vertical line is 20-70 degrees; the coaming corresponds to a first arc plate, a second arc plate and a third arc plate which are in tangential transition in sequence between the arc transition surface and the first leading-out plate; the blades of the wind wheel are formed by tangential transitional connection of an inner arc piece and an outer arc piece. According to the invention, through optimizing the structures and the sizes of the air outlet, the air duct and the wind wheel, the whole air outlet is reasonably and gradually increased from inside to outside, the increase of the air discharge quantity and the air discharge pressure is realized, and the discharged air can be transmitted to a more distant position.

Description

Large air volume volute fan

Technical Field

The invention relates to a volute wind wheel, in particular to a large-air-volume volute fan.

Background

The current spiral case fan wide application in trades such as smoke ventilator, it includes spiral case, wind wheel and motor, the spiral case is enclosed by front end housing, bounding wall and rear end cap, and the bounding wall is the opening cyclic annular, and front end housing and rear end cap set up respectively in the front and back both sides of bounding wall, and bounding wall, front end housing and rear end cap enclose into the air flue jointly, and the opening part of bounding wall is equipped with the air outlet, and front end housing and rear end cap surface are equipped with preceding air intake and rear air intake respectively, are equipped with the motor frame on the rear air intake, and the motor setting is in the motor frame, and the wind wheel setting is in the air flue to be connected with motor drive. The radius of the wind wheel for the smoke exhaust ventilator is generally 125mm to 155mm, and the left side and the right side of the air outlet of the corresponding volute are parallel, so that the discharged control is accumulated at the air outlet and cannot be discharged in time, the air outlet quantity is influenced, and meanwhile, the static pressure of the air inlet of the wind wheel is reduced, and the smoking effect is poor. In order to overcome this problem, the air outlet of some products is vertically arranged upwards, so that the width of the end, connected with the air duct, of the air outlet is increased as much as possible, and at this time, although the control in the air duct can be quickly discharged, the air flow rate of the air outlet is reduced due to the smaller pressure in the air duct. In addition, the coaming of above-mentioned structure is adopted two sections of non-concentric circular arc boards to connect between the both sides of corresponding air outlet to form, consequently, involute speed increase between coaming internal surface and the wind wheel centre of a circle is very fast, so that the air that the wind wheel throws away is not enough to the process pressure of air outlet through wind channel propelling movement, and the wind speed drops, and also, the air pressure that appears outside discharge flue easily is greater than fan blowout air pressure, and when smoke ventilator actual installation was used, because the exhaust passage is longer, because fan air outlet exhaust pressure is less, so external air flows backward.

In addition, the current wind wheel comprises a wheel hub, more than two supporting rings and a plurality of blades, wherein the blades are circularly and uniformly distributed around the center of the wheel hub and are connected with the periphery of the wheel hub, both ends of each blade are respectively connected with the supporting rings, the cross section of each blade is in an arc shape, and the arc shape is single, namely the radians of all the positions are consistent, and the periphery of the wind wheel which cannot be the wind wheel forms larger wind pressure, so that the problems of reduced suction and small air output are also caused.

Disclosure of Invention

The invention aims to provide a large-air-volume volute fan which is reasonable in structure and can increase static pressure and air volume during operation.

The purpose of the invention is realized in the following way:

The utility model provides a big amount of wind spiral case fan, including spiral case, wind wheel and motor, the spiral case is enclosed by front end housing, bounding wall and rear end cap, and the bounding wall is the opening ring-shaped, and front end housing and rear end cap set up respectively in the front and back both sides of bounding wall, and bounding wall, front end housing and rear end cap enclose into the air flue jointly, and the opening part of bounding wall is equipped with the air outlet, and front end housing and rear end cap surface are equipped with preceding air intake and back air intake respectively, are equipped with the motor frame on the back air intake, and the motor setting is in the motor frame, and the wind wheel setting is in the wind channel, and is connected with motor drive, its characterized in that: the left side and the right side of the air outlet are respectively provided with a first extraction plate and a second extraction plate, the first extraction plate is in tangential transition with one end of an opening of the coaming, the second extraction plate is connected with the other end of the opening of the coaming through an arc transition surface, the horizontal distance D from the tangent point T of the arc transition surface and a vertical line to the first extraction plate is 125mm to 155mm, and the included angle alpha between the second extraction plate and the vertical line is 20 degrees to 70 degrees; the coaming is a first arc plate, a second arc plate and a third arc plate which are in tangential transition in sequence between the corresponding arc transition surface of the coaming and the first leading-out plate, the circle center of the first arc plate, the circle center of the second arc plate and the circle center of the third arc plate are distributed in a triangle, the first arc plate is in tangential transition with the arc transition surface, and the third arc plate is in tangential transition with the first leading-out plate; the blades of the wind wheel are formed by tangential transitional connection of an inner arc piece and an outer arc piece, the inner arc piece is close to the inner circle side of the wind wheel, and the outer arc piece is close to the outer circle side of the wind wheel.

The aim of the invention can be also solved by adopting the following technical measures:

As a more specific scheme, the horizontal distance D from the tangent point T of the arc transition surface and the vertical line to the first end tab is 130mm to 135mm, the included angle α between the second end tab and the vertical line is 40 degrees to 45 degrees, and the radius R1 of the arc transition surface facing to one side cambered surface in the air outlet is 8.0mm to 9.0mm.

As a further scheme, the second leading-out plate, the arc transition surface, the first arc plate, the second arc plate, the third arc plate and the first leading-out plate are formed by bending a sheet metal part; the arc radius R2 of the inner side surface of the first arc plate is 140-160 mm, and the arc radian of the inner side surface of the first arc plate is 100-110 degrees; the arc radius R3 of the inner side surface of the second arc plate is 175-195 mm, and the arc radian of the inner side surface of the second arc plate is 20-60 degrees; the inner side surface arc radius R4 of the third arc plate is 180-210 mm, and the inner side surface arc radian of the third arc plate is 130-170 degrees.

As a further proposal, the edge of the front end cover is riveted with the front side edge of the coaming, and the edge of the rear end cover is riveted with the rear side edge of the coaming.

As a further scheme, the wind wheel comprises a hub, more than two supporting rings and a plurality of blades, wherein the blades are circularly and uniformly distributed around the center of the hub and are connected with the periphery of the hub, and two ends of each blade are respectively connected with the supporting rings; the arc radius of the inner arc piece is 9.2mm to 18.6mm, and the arc radius of the outer arc piece is 18mm to 30mm. The arc radius of the inner arc piece and the arc radius of the outer arc piece take the center line between the respective outer arc surface and the inner arc surface as measurement references.

As a further scheme, the inner arc piece and the outer arc piece are integrally bent by a sheet metal part, the total length of the arc lines of the inner arc piece and the outer arc piece is 22.5mm to 34mm, and the arc line length of the inner arc piece is 1mm to 2mm longer than that of the outer arc piece. The total length of the inner arc and the total length of the outer arc take the center line between the outer arc surface and the inner arc surface as measurement references.

As a further scheme, the diameter of the circumference of the inner end of the blade is 185mm to 256mm, and the diameter of the circumference of the outer end of the blade is 256mm to 300mm; the front air inlet of the front end cover is provided with a cover ring, and the distance between the inner circumference of the cover ring and the circumference of the inner end of the blade is 4mm to 10mm.

As a further scheme, the height of the blade is 105mm to 163mm, the upper end and the lower end of the blade are respectively provided with a buckling lug, and the buckling lugs penetrate through the surface of the supporting ring and then are bent so as to be buckled on the outer end face of the supporting ring; the upper and lower both ends of the inner arc piece of blade all are equipped with drag reduction chamfer, and drag reduction chamfer's orthographic projection is right triangle, and drag reduction chamfer's horizontal side length is 2mm to 3mm, and drag reduction chamfer's vertical side length is 10mm to 15mm. The drag reduction chamfer can reduce the resistance of air inlet and noise.

As a further scheme, in two adjacent blades, the vertical distance from one end of the inner cambered surface of the outer cambered surface of one blade close to the excircle of the wind wheel to the outer cambered surface of the adjacent blade is 2.7mm to 7mm. The greater the density of the blade distribution, the smaller the distance.

As a further scheme, the included angle between the connecting line of one end of the blade, which is close to the outer circle of the wind wheel, to the center of the wind wheel and the connecting line of one end of the blade, which is close to the inner circle of the wind wheel, to the center of the wind wheel is 6-8 degrees.

The beneficial effects of the invention are as follows:

(1) According to the invention, the size of one end of the air outlet, which is connected with the air duct, is adjusted, and the sectional area between the inner end and the outer end of the air outlet is adjusted, so that the whole air outlet is reasonably and gradually increased from inside to outside, the increase of the air discharge quantity and the air discharge pressure is realized, and the discharged air can be transmitted to a farther position;

(2) The inner wall of the air channel is in tangent smooth transition through the three sections of arc surfaces, so that air flows more smoothly in the air channel, noise is smaller, the distance between the outer arc surface of the air channel from the inner end to the outlet end and the center of the wind wheel is increased linearly, the pressure of the air thrown out by the wind wheel is sufficient in the process of pushing the air from the wind channel to the air outlet, the wind speed is higher, and the static pressure and the wind volume of the air blown out by the fan are increased;

(3) The blades of the wind wheel adopt a design of integrally connecting the tangential transition of the double arc sheets, and the parameters such as the radius of the inner arc sheet close to the inner circle, the radius of the outer arc sheet close to the outer circle and the like are reasonably designed, so that the static pressure and the wind volume can be increased when the wind wheel works.

(4) The invention is mainly suitable for the smoke exhaust ventilator, has stronger smoke exhausting capability due to the increase of the air exhaust quantity and the static pressure, and can avoid the backward flow of the smoke in the flue during the working.

(5) According to the invention, the edge of the front end cover is riveted with the front side edge of the coaming, and the edge of the rear end cover is riveted with the rear side edge of the coaming, so that the structure of the volute fan is convenient to process and install, and the structure manufacturing cost of the volute fan is lower.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the present invention.

FIG. 2 is a schematic view of another angle structure of the present invention.

Fig. 3 is a schematic left-view structure of the present invention.

Fig. 4 is a schematic view of the cross-sectional A-A structure of fig. 3.

Fig. 5 is a schematic view of the contour structure of the inner side of the coaming in fig. 4.

Fig. 6 is a schematic view of a three-dimensional structure of a coaming plate in the present invention.

FIG. 7 is a schematic view of the cross-sectional B-B structure of FIG. 3.

Fig. 8 is an enlarged schematic view of fig. 7 at C.

Fig. 9 is a schematic diagram of a front view structure of the present invention.

Fig. 10 is a schematic view of the D-D cross-sectional structure of fig. 9.

Fig. 11 is a schematic view of a cross-sectional structure of a wind turbine according to the present invention.

FIG. 12 is a schematic view of a cross-sectional view of a blade according to the present invention.

Fig. 13 is an enlarged schematic view of the structure at E in fig. 11.

FIG. 14 is a schematic view of an angle structure of a blade according to the present invention.

Fig. 15 is an enlarged schematic view of the structure at F in fig. 14.

Fig. 16 is a schematic view showing the front view of the vane according to the present invention.

FIG. 17 is a schematic view of an angle configuration of a wind turbine according to the present invention.

Fig. 18 is a schematic view of another angle structure of the wind wheel in the present invention.

Fig. 19 is an exploded view of another embodiment of the scroll casing according to the present invention.

Fig. 20 is an enlarged schematic view of the structure at G of fig. 19.

Fig. 21 is an enlarged schematic view of the structure at I of fig. 19.

Fig. 22 is an enlarged schematic view of the structure at J of fig. 19.

Fig. 23 is an enlarged schematic view of the structure at K in fig. 19.

Fig. 24 is a schematic view of another angularly exploded construction of fig. 19.

Fig. 25 is a schematic view of another angular configuration of the scroll casing of fig. 19 after assembly.

Fig. 26 is a schematic front view of fig. 25.

Fig. 27 is a schematic view of the P-P cross-sectional structure of fig. 26.

Fig. 28 is an enlarged schematic view of the structure at Q of fig. 27.

Fig. 29 is an enlarged schematic view of the structure at U of fig. 27.

Detailed Description

The invention is further described below with reference to the drawings and examples.

Referring to fig. 1 to 10, a large-air-volume volute fan comprises a volute 20, a wind wheel 10 and a motor 8, wherein the volute 20 is formed by enclosing a front end cover 4, a surrounding plate 5 and a rear end cover 7, the surrounding plate 5 is in an open ring shape, the front end cover 4 and the rear end cover 7 are respectively arranged on the front side and the rear side of the surrounding plate 5, the front end cover 4 and the rear end cover 7 jointly enclose an air channel 58, an air outlet 51 is arranged at the opening of the surrounding plate 5, a front air inlet 41 and a rear air inlet 71 are respectively arranged on the surfaces of the front end cover 4 and the rear end cover 7, a motor 8 frame 72 is arranged on the rear air inlet 71, the motor 8 is arranged on the motor 8 frame 72, and the wind wheel 10 is arranged in the air channel 58 and is in transmission connection with the motor 8. The left and right sides of the air outlet 51 are respectively provided with a first extraction plate 55 and a second extraction plate 56, the second extraction plate 56 is connected with one end of the opening of the coaming 5 through an arc transition surface 57, the coaming 5 corresponds to a first arc plate 52, a second arc plate 53 and a third arc plate 54 which are in tangent transition between the arc transition surface 57 and the first extraction plate 55 in sequence, the circle centers O2 of the first arc plate 52, the circle centers O3 of the second arc plate 53 and the circle centers O4 of the third arc plate 54 are distributed in a triangle shape and are positioned on the inner side of the coaming 5, the first arc plate 52 is in tangent transition with the arc transition surface 57, and the third arc plate 54 is in tangent transition with the first extraction plate 55. In fig. 5: the point a is the outer end of the second end tab 56, the point b is the junction of the second end tab 56 and the arc transition surface 57, the point c is the junction of the arc transition surface 57 and the first arc plate 52, the point d is the junction of the first arc plate 52 and the second arc plate 53, the point e is the junction of the second arc plate 53 and the third arc plate 54, the point f is the junction of the third arc plate 54 and the first end tab 55, and the point g is the outer end of the first end tab 55.

The arc radius R2 of the inner side surface of the first arc plate 52 is 148mm to 152mm, and the arc radian of the inner side surface of the first arc plate 52 is 105 degrees to 110 degrees; the arc radius R3 of the inner side surface of the second arc plate 53 is 180-190 mm, and the arc radian of the inner side surface of the second arc plate 53 is 28-42 degrees; the radius R4 of the inner side arc of the third arc plate 54 is 190mm to 200mm, and the radian of the inner side arc of the third arc plate 54 is 145 degrees to 160 degrees.

The horizontal distance D from the tangent point T of the arc transition surface 57 and the vertical line L to the first end tab 55 is 130mm to 135mm, and the second end tab 56 is inclined outward and has an included angle alpha with the vertical line L of 40 degrees to 45 degrees.

The radius R1 of the arc transition surface 57 facing the arc surface on one side in the air outlet 51 is 8.0mm to 9.0mm. The circle center O1 of the arc transition surface 57 is located outside the coaming 5.

The first end tab 55 is inclined toward the inner side of the air outlet 51, and the angle β between the first end tab 55 and the vertical line L is smaller than the angle α between the second end tab 56 and the vertical line L.

The outer end face of the air outlet 51 is provided with a frame 6, the surfaces of the front end cover 4 and the rear end cover 7 are respectively provided with a front air inlet 41 and a rear air inlet 71, and the rear air inlet 71 is provided with a motor frame 72.

The wind channel 58 is equipped with wind wheel 10, be equipped with motor 8 on the motor frame 72, motor 8 and wind wheel 10 transmission connection, the radius of wind wheel 10 is 125mm to 155mm.

The front air inlet 41 of the front end cover 4 is provided with a cover ring 42. The cross section of the cover ring 42 is in a circular arc flanging shape. The rear end cover 7 is also provided with a volute bracket 73.

The first arc plate 52, the second arc plate 53 and the third arc plate 54 are sequentially arranged between the arc transition surface 57 corresponding to the coaming 5 and the first draw-out plate 55, and the second draw-out plate 56, the arc transition surface 57, the first arc plate 52, the second arc plate 53, the third arc plate 54 and the first draw-out plate 55 are formed by bending a sheet metal part.

A plurality of blades 1 are annularly distributed on the wind wheel 10, and the difference value between the radius R6 from the circumference of the inner end of each blade 1 to the circle center O5 of the wind wheel 10 and the radius R5 from the inner circumference of the cover ring 42 to the circle center O5 of the wind wheel 10 is 4mm to 10mm.

Referring to fig. 11 to 18, the wind wheel 10 includes a hub 3, two support rings 2, and a plurality of blades 1, wherein the plurality of blades 1 are circularly and uniformly distributed around the center of the hub 3 and are connected with the periphery of the hub 3, two ends of each blade 1 are respectively connected with the support rings 2, the blades 1 are formed by connecting inner arc pieces 11 and outer arc pieces 12 in a tangential transitional manner, the inner arc pieces 11 are close to the inner circle side of the wind wheel 10, and the outer arc pieces 12 are close to the outer circle side of the wind wheel 10.

The arc radius RN of the inner arc 11 is 9.2mm to 18.6mm and the arc radius RW of the outer arc 12 is 18mm to 30mm. The arc radius RN of the inner arc piece 11 and the arc radius RW of the outer arc piece 12 are preferably measured with the center lines L1 and L2 between the outer arc surface and the inner arc surface thereof as measurement references: the arc radius RN of the inner arc 11 is 12mm to 13mm and the arc radius RW of the outer arc 12 is 24mm to 25mm.

The inner arc piece 11 and the outer arc piece 12 are formed by integrally bending a sheet metal part, and the total arc length of the inner arc piece 11 and the outer arc piece 12 is 22.5mm to 34mm, preferably: the total arc length of the inner arc piece 11 and the outer arc piece 12 is 26mm to 30mm. The arc length LN of the inner arc 11 is 1mm to 2mm longer than the arc length LW of the outer arc 12.

The inner diameter DN of the circumference of the blade 1 is 185mm to 256mm, the outer diameter DW of the circumference of the blade 1 is 256mm to 300mm, and the following steps are preferable: the inner diameter DN of the circumference of the blade 1 is 220mm to 225mm, and the outer diameter DW of the circumference of the blade 1 is 260mm to 270mm.

The height H of the blade 1 is 105mm to 163mm, the upper end and the lower end of the blade 1 are respectively provided with a buckling lug 13, and the buckling lugs 13 penetrate through the surface of the support ring 2 and then are bent so as to be buckled on the outer end face of the support ring 2; the upper end and the lower end of the inner arc piece 11 of the blade 1 are respectively provided with a drag reduction chamfer 14, orthographic projection of the drag reduction chamfer 14 is formed by enclosing right-angled triangles m1, m2 and m3, the horizontal side length D1 of the drag reduction chamfer 14 is 2mm to 3mm, and the vertical side length D2 of the drag reduction chamfer 14 is 10mm to 15mm. Wherein, the extending surface of the upper end of the blade 1, the extending surface of the inner end of the blade 1 and the extending surface of the drag reduction chamfer 14 jointly enclose the right triangle m1, m2 and m3.

In the two adjacent blades 1, the vertical distance S1 between one end O7 of the inner cambered surface of the outer cambered surface 12 of one blade 1, which is close to the outer circle of the wind wheel 10, and the outer cambered surface of the outer cambered surface 12 of the adjacent blade 1 is 2.7mm to 7mm.

And an included angle gamma between a connecting line from one end O7 of the blade 1, which is close to the outer circle of the wind wheel 10, to the circle center O5 of the wind wheel 10 and a connecting line from one end O6 of the blade 1, which is close to the inner circle of the wind wheel 10, to the circle center 05 of the wind wheel 10 is 6-8 degrees.

As a further solution, as shown in fig. 19 to 29, the edge of the front end cover 4 is provided with a front flanging 43, the front side edge of the coaming 5 is provided with a front flanging 59, the rear side edge of the coaming 5 is provided with a rear flanging 50, the edge of the rear end cover 7 is provided with a rear flanging 74, the front flanging 43 is riveted with the front flanging 59, and the rear flanging 50 is riveted with the rear flanging 74.

The forward bent edge 59 sequentially comprises a first transverse edge 591, a first longitudinal edge 592, a second transverse edge 593 and a second longitudinal edge 594, the inner walls of the first transverse edge 591, the first longitudinal edge 592, the second transverse edge 593 and the second longitudinal edge 594 enclose a first clamping groove 595, and the first clamping groove 595 is clamped and riveted with the front outer edge 43.

The backward bending edge 50 sequentially comprises a third transverse edge 501, a third longitudinal edge 502, a fourth transverse edge 503 and a fourth longitudinal edge 504, wherein the inner walls of the third transverse edge 501, the third longitudinal edge 502, the fourth transverse edge 503 and the fourth longitudinal edge 504 enclose a second clamping groove 505, and the second clamping groove 505 is clamped and riveted with the backward external edge 74.

The rear end cover 7 and the motor frame 72 are integrally formed.

Claims

1. The utility model provides a big amount of wind spiral case fan, including spiral case (20), wind wheel (10) and motor (8), spiral case (20) are enclosed by front end housing (4), bounding wall (5) and rear end housing (7), bounding wall (5) are the opening cyclic annular, front end housing (4) and rear end housing (7) set up respectively in the front and back both sides of bounding wall (5), front end housing (4) and rear end housing (7) enclose jointly into wind channel (58), the opening part of bounding wall (5) is equipped with air outlet (51), front end housing (4) and rear end housing (7) surface are equipped with preceding air intake (41) and rear air intake (71) respectively, be equipped with motor (8) frame (72) on rear air intake (71), motor (8) set up on motor (8) frame (72), wind wheel (10) set up in wind channel (58) and with motor (8) transmission connection, its characterized in that: the left side and the right side of the air outlet (51) are respectively provided with a first extraction plate (55) and a second extraction plate (56), the first extraction plate (55) is in tangential transition with one end of an opening of the coaming (5), the second extraction plate (56) is connected with the other end of the opening of the coaming (5) through an arc transition surface (57), the horizontal distance D from the tangential point T of the arc transition surface (57) and a vertical line to the first extraction plate (55) is 125mm to 155mm, and the included angle alpha between the second extraction plate (56) and the vertical line is 20 degrees to 70 degrees; the coaming (5) is a first arc plate (52), a second arc plate (53) and a third arc plate (54) which are in tangent transition in sequence between a corresponding arc transition surface (57) and a first leading-out plate (55), the circle centers of the first arc plate (52), the second arc plate (53) and the third arc plate (54) are distributed in a triangle, the first arc plate (52) is in tangent transition with the arc transition surface (57), and the third arc plate (54) is in tangent transition with the first leading-out plate (55); the blades of the wind wheel (10) are formed by tangential transition connection of inner arc sheets and outer arc sheets, the inner arc sheets are close to the inner circle side of the wind wheel (10), and the outer arc sheets are close to the outer circle side of the wind wheel (10);

The inner arc piece and the outer arc piece are formed by integrally bending a sheet metal part, the total arc length of the inner arc piece and the outer arc piece is 22.5mm to 34mm, and the arc length of the inner arc piece is 1mm to 2mm longer than the arc length of the outer arc piece;

The diameter of the circumference of the inner end of the blade is 185mm to 256mm, and the diameter of the circumference of the outer end of the blade is 256mm to 300mm; the front air inlet (41) of the front end cover (4) is provided with a cover ring (42), and the distance between the inner periphery of the cover ring (42) and the circumference of the inner end of the blade is 4mm to 10mm;

The height of the blade is 105mm to 163mm, the upper end and the lower end of the blade are respectively provided with a buckling lug, and the buckling lugs penetrate through the surface of the supporting ring and then are bent so as to be buckled on the outer end face of the supporting ring; the upper end and the lower end of the inner arc piece of the blade are respectively provided with a drag reduction chamfer, the orthographic projection of the drag reduction chamfer is a right triangle, the horizontal side length of the drag reduction chamfer is 2mm to 3mm, and the vertical side length of the drag reduction chamfer is 10mm to 15mm;

The edge of the front end cover (4) is provided with a front flanging (43), the front side edge of the coaming (5) is provided with a front bending edge (59), the rear side edge of the coaming (5) is provided with a rear bending edge (50), the edge of the rear end cover (7) is provided with a rear flanging (74), the front flanging (43) is riveted with the front bending edge (59), and the rear bending edge (50) is riveted with the rear flanging (74);

The front bending edge (59) sequentially comprises a first transverse edge (591), a first longitudinal edge (592), a second transverse edge (593) and a second longitudinal edge (594), wherein the inner walls of the first transverse edge (591), the first longitudinal edge (592), the second transverse edge (593) and the second longitudinal edge (594) enclose a first clamping groove (595), and the first clamping groove (595) and the front outer edge (43) are clamped and riveted;

The backward bending edge (50) sequentially comprises a third transverse edge (501), a third longitudinal edge (502), a fourth transverse edge (503) and a fourth longitudinal edge (504), wherein the inner walls of the third transverse edge (501), the third longitudinal edge (502), the fourth transverse edge (503) and the fourth longitudinal edge (504) enclose a second clamping groove (505), and the second clamping groove (505) is clamped and riveted with the backward external edge (74).

2. The large air volume scroll fan of claim 1, wherein: the horizontal distance D from the tangential point T of the arc transition surface (57) and the vertical line to the first extraction plate (55) is 130-135 mm, the included angle alpha of the second extraction plate (56) and the vertical line is 40-45 degrees, and the radius R1 of one side cambered surface of the arc transition surface (57) facing the air outlet (51) is 8.0-9.0 mm.

3. The large air volume scroll fan of claim 1, wherein: the second extraction plate (56), the arc transition surface (57), the first arc plate (52), the second arc plate (53), the third arc plate (54) and the first extraction plate (55) are formed by bending a sheet metal part; the arc radius R2 of the inner side surface of the first arc plate (52) is 140-160 mm, and the arc radian of the inner side surface of the first arc plate (52) is 100-110 degrees; the arc radius R3 of the inner side surface of the second arc plate (53) is 175-195 mm, and the arc radian of the inner side surface of the second arc plate (53) is 20-60 degrees; the inner side surface arc radius R4 of the third arc plate (54) is 180-210 mm, and the inner side surface arc radian of the third arc plate (54) is 130-170 degrees.

4. A large volume volute fan according to claim 3, wherein: the edge of the front end cover (4) is riveted with the front side edge of the coaming (5), and the edge of the rear end cover (7) is riveted with the rear side edge of the coaming (5).

5. The large air volume scroll fan of claim 1, wherein: the wind wheel (10) comprises a hub, more than two supporting rings and a plurality of blades, wherein the blades are circularly and uniformly distributed around the center of the hub and are connected with the periphery of the hub, and two ends of each blade are respectively connected with the supporting rings; the arc radius of the inner arc piece is 9.2mm to 18.6mm, and the arc radius of the outer arc piece is 18mm to 30mm.

6. The large air volume scroll fan of claim 1, wherein: in the two adjacent blades, the vertical distance from one end of the inner cambered surface of the outer cambered surface of one blade close to the outer circle of the wind wheel (10) to the outer cambered surface of the adjacent blade is 2.7mm to 7mm.

7. The large air volume scroll fan of claim 1, wherein: the included angle between the connecting line of one end of the blade, which is close to the outer circle of the wind wheel (10), to the center of the wind wheel (10) and the connecting line of one end of the blade, which is close to the inner circle of the wind wheel (10), to the center of the wind wheel (10) is 6-8 degrees.