A variable cross-section turbulent flow fan blade for large-scale industry

Abstract

The present invention discloses a variable cross-section turbulent flow fan blade for large-scale industry. The blade includes a hollow main body having an internal cavity, and further includes a solid turbulent flow wing connected to the rear side edge of the blade and extending along the root-tail direction of the rear side edge. At the rear side edge of the turbulent flow wing, there are turbulene teeth continuously distributed periodically along the root-tail direction. Each turbulene tooth at least includes a turbulent flow side extending along the root-tail direction and gradually narrowing towards the main body side. The blade of the present invention takes into account the large wind force gap between the root and the tail of the industrial fan and the discomfort problem of continuous wind blowing on people. It uses turbulent flow to simulate natural wind and balance the wind force gap inside and outside the center, truly solving the application pain points of industrial large fans, improving the large environment of the factory, and enhancing the comfort of the staff under the fan.

Description

Technical Field

[0001] The present invention belongs to the technical field of large fans, and particularly relates to a variable cross-section turbulent flow fan blade for large industrial use. Background Art

[0002] Fans are very common in daily life. However, the common ones in daily life are small household fans, which are small in size. The length of a single blade is usually about 20 - 60 cm, and basically does not exceed 80 cm, which can meet the needs of household use. Since the fan blade is short in length and the use distance is close, the blade design is usually relatively "thick and wide". A typical example is the type described in Patent CN201930400024.X, which is a common fan type among ordinary social residents.

[0003] Another type of large fan is usually used in factory environments and is not commonly seen by the public but can be seen in factories. For example, an industrial fan structure described in Patent CN201821670252.5. The length of such large fan blades can reach 2 m - 10 m. Due to the large length, they are usually hoisted to cover a large range and improve the ventilation environment in the factory.

[0004] Existing large fan blades generally have the following deficiencies. Since the fan operates in a circular motion, the linear speeds of the head and tail of the blade during the operation of the fan are different. Moreover, due to the relatively long blade length, the difference in linear speeds is relatively large, even several times. For a wind blade with a uniform cross-section, since the cross-sectional shapes of the head and tail are the same, the difference in linear speeds causes a large difference in the air volume between the center and the edge of the fan: the air volume at the center of the fan is small, and the air volume at the edge of the fan is large, and the wind diffusion range is small, resulting in a poor user experience.

[0005] To solve the above problems, there is no solution in the field of industrial large fans. In the field of small fans, there is an inconspicuous design solution. For example, a blade formed by injection molding described in the existing Patent CN201820382904.9 has a width that smoothly decreases from the root to the tail. This smoothly decreasing solution in the technical solution of its original document is mainly to solve the problem of insufficient plastic rigidity, so the width of the root is designed to be larger. The problem solved by this design method is the rigidity problem. Since the length of the blade of a small fan is small and the wind pushed out by the fan blade is in a diffused form, the change in wind force between the root and the tail of the blade is not obvious. However, if this solution is applied to the above problems, it can be regarded as a solution, that is, at the root where the linear speed is relatively small, the width of the fan blade is designed to be larger, so that the root blade can increase the wind force when the linear speed is relatively small.

[0006] However, all of the above solutions have another problem. That is, the wind of traditional industrial large fans blows continuously. In large industrial workshops, especially on sweltering days, the fans need to work continuously to blow air. Due to the relatively continuous and stable wind direction and force, workers working under the fans for a day will be blown by the continuous wind all day, which is definitely uncomfortable. Under normal circumstances, in ordinary household fans, family members will not blow themselves continuously all day long. In addition, the exhaust fans commonly seen in some factories will work continuously, but they are used for exhausting air and will not directly blow on people. Summary of the Invention

[0007] The object of the present invention is to solve the above-mentioned existing technical problems, and provide a variable cross-section turbulent flow fan blade for large-scale industry. At the same time, considering the large wind force gap between the root and the tail of industrial fans, and the discomfort caused by continuous blowing of people, the turbulent flow is used to simulate natural wind and balance the wind force gap inside and outside the center, truly solving the application pain points of industrial large fans, improving the large environment of factories, enhancing the comfort of workers under the fans, and being beneficial to improving their production and work efficiency; further, enabling industrial large fans to be truly widely applied.

[0008] In order to achieve the above invention object, the technical solution adopted by the present invention is as follows: A variable cross-section turbulent flow fan blade for large-scale industry, the blade includes an extruded hollow main body, the main body has an internal cavity along the direction from the root to the tail of the blade, and the cavity is surrounded by the upper and lower surfaces of the main body; the upper and lower surfaces of the main body are arc-transitioned at the front side of the blade movement and gradually converge at the rear side of the blade movement;

[0009] The upper surface of the main body is an arc surface from the front side to the rear side of the movement direction. Between the upper surface and the lower surface, the vertical distance in the middle is high, and the vertical distance on both sides is low. The upper surface and the lower surface gradually bend downward and converge at the rear side.

[0010] It also includes a solid turbulent flow wing connected to the rear side of the blade and extending along the root-tail direction of the rear side. The upper and lower surfaces of the turbulent flow wing are smoothly transitioned along the tangent direction with the upper and lower surfaces of the main body at the connection.

[0011] At the rear side of the turbulent flow wing, there are turbulences continuously distributed periodically along the root-tail direction. Each turbulence includes at least a turbulent flow edge extending along the root-tail direction and gradually narrowing towards the main body side.

[0012] Preferably, the distance between each turbulence and the main body is the same, gradually decreases or decreases stepwise along the root-tail direction;

[0013] The stepwise decrease means that each turbulence is divided into several continuous groups along the root-tail direction. The distance between the turbulences within the group is the same, and the distance between the turbulences in the group in the tail direction is less than the distance between the turbulences in the group in the root direction and the main body.

[0014] Preferably, the point where each flocculation tooth is farthest from the main body is the tooth tip, and the side of the tooth tip facing the tail direction is the flocculation flow edge.

[0015] Preferably, the side of the tooth tip facing the root direction is the flow rectifying edge, and the flow rectifying edge extends towards the root direction and gradually narrows towards the main body side or is flush; the flow rectifying edge flush with the main body side and the corresponding flocculation flow wing part form a flow rectifying plate.

[0016] Preferably, the flocculation teeth are large teeth in an arc shape or a stepped shape, or the flocculation teeth are small teeth in a toothed shape.

[0017] Preferably, a support column connecting the upper and lower surfaces of the main body is provided inside the cavity, and the column divides the cavity into a front chamber and a rear chamber in the front-back direction of the movement, and the lower surface of the main body starts to bend downward from the corresponding part of the rear chamber.

[0018] Preferably, the flocculation flow wing extends linearly or arcuately towards the rear side from the connection with the main body.

[0019] Preferably, the blade is made of aluminum or its alloy.

[0020] Preferably, the flocculation flow wing and the main body are integrally formed and fixed or assembled and fixed to each other.

[0021] Preferably, the length of the blade is 2m to 10m. Description of the Drawings

[0022] Figure 1 is a perspective view of the blade in the first embodiment of the present invention;

[0023] Figure 2 is Figure 1 the enlarged view of part A in

[0024] Figure 3 is Figure 1 the enlarged view of part B in

[0025] Figure 4 is a cross-sectional view of the blade in the first embodiment of the present invention;

[0026] Figure 5 is a top view of the blade in the first embodiment of the present invention;

[0027] Figure 6 is a top view of the blade in the second embodiment of the present invention;

[0028] Figure 7 is a perspective view of the blade in the second embodiment of the present invention;

[0029] Figure 8 is Figure 7 the enlarged view of part C in

[0030] Figure 9 Stereoscopic view of the three - blade of the embodiment of the present invention;

[0031] Figure 10 Top view of the three - blade of the embodiment of the present invention;

[0032] Figure 11 Top view of the four - blade of the embodiment of the present invention;

[0033] Figure 12 Stereoscopic view of the four - blade of the embodiment of the present invention;

[0034] Figure 13 Stereoscopic view of the five - blade of the embodiment of the present invention;

[0035] Figure 14 Top view of the five - blade of the embodiment of the present invention;

[0036] Figure 15 Wind power density distribution diagram of a blade with a constant cross - section in the prior art;

[0037] Figure 16 Wind power density distribution diagram of the variable - cross - section blade of the present invention;

[0038] Figure 17 Schematic diagram of the principle of the turbulent flow wing of the fan blade of the present invention cutting the air flow;

[0039] Figure 18 Another schematic diagram of the principle of the turbulent flow wing of the fan blade of the present invention cutting the air flow; Detailed implementation manners

[0040] To facilitate the understanding of the present invention, the present invention will be described in more detail below with reference to the relevant drawings.

[0041] Embodiment 1

[0042] As Figures 1 to 5 shown, it is a schematic structural diagram of a variable - cross - section turbulent flow fan blade for large - scale industrial use in this embodiment.

[0043] The blade 1 of this embodiment includes a hollow main body 10 formed by extrusion molding. The main body 10 has an internal cavity 11 along the direction from the root to the tail of the blade. The cavity is surrounded by the upper surface 101 and the lower surface 102 of the main body. The upper and lower surfaces of the main body are in arc transition at the front side of the blade movement and gradually converge at the rear side of the blade movement.

[0044] The upper surface 101 of the main body 10 is an arc - shaped surface from the front side to the rear side of the movement direction. Between the upper surface and the lower surface, the vertical distance in the middle is high, and the vertical distance on both sides is low. The upper surface and the lower surface gradually bend downward and converge at the rear side.

[0045] Inside the cavity 11, there is a support column 12 connecting the upper and lower surfaces of the main body. The column 12 divides the cavity 11 into a front chamber 111 and a rear chamber 112 in the front-back direction of the movement. The lower surface 102 of the main body starts to bend downward from the corresponding part of the rear chamber 112.

[0046] It also includes a solid flocculation wing 20 connected to the rear side edge of the blade and extending along the root-tail direction of the rear side edge. The upper and lower surfaces of the flocculation wing 20 are smoothly transitioned along the tangent direction with the upper and lower surfaces of the main body at the connection; the flocculation wing extends linearly backward from the connection with the main body, and in other embodiments, it can also be arc-shaped extension.

[0047] At the rear side edge of the flocculation wing 20, there are flocculation teeth 21 continuously distributed periodically along the root-tail direction. The maximum distance between each flocculation tooth 21 and the main body 10 is the tooth tip. The side of the tooth tip facing the tail direction is the flocculation flow side 211, and the flocculation flow side 211 extends along the blade tail direction and gradually narrows toward the main body 10 side.

[0048] The side of the tooth tip facing the root direction is the rectifying side 212, and the rectifying side 212 extends toward the root direction and gradually narrows toward the main body 10 side.

[0049] The flocculation teeth 21 are small tooth-shaped teeth, and the distance between each flocculation tooth 21 and the main body 10 is the same.

[0050] The blade 1 is made of aluminum or its alloy.

[0051] The flocculation wing 20 and the main body are integrally formed and fixed.

[0052] Embodiment 2

[0053] As Figures 6 to 8 shown, it is a schematic structural diagram of the variable cross-section flocculation fan blade for large industrial use in this embodiment.

[0054] The blade of this embodiment includes an extruded hollow main body 10a. The main body 10a has an internal cavity along the root-to-tail direction of the blade. The cavity is surrounded by the upper and lower surfaces of the main body; the upper and lower surfaces of the main body are arc-transitioned at the front side of the blade movement and gradually converge at the rear side of the blade movement.

[0055] The upper surface of the main body 10a is an arc-shaped surface from the front side to the rear side of the movement direction. Between the upper surface and the lower surface, the vertical distance in the middle is high, and the vertical distance on both sides is low. The upper surface and the lower surface gradually bend downward and converge at the rear side.

[0056] Inside the cavity, there is a support column connecting the upper and lower surfaces of the main body. The column divides the cavity into a front chamber and a rear chamber in the front-back direction of the movement. The lower surface of the main body starts to bend downward from the corresponding part of the rear chamber.

[0057] It further includes a solid flocculent flow wing 20a connected to the rear side edge of the blade and extending along the root-tail direction of the rear side edge. The upper and lower surfaces of the flocculent flow wing 20a are smoothly transitioned along the tangential direction with the upper and lower surfaces of the main body at the connection. The flocculent flow wing extends linearly backward from the connection with the main body, and in other embodiments, it can also extend in an arc.

[0058] At the rear side edge of the flocculent flow wing 20a, there are flocculent teeth 21a, 22a that are continuously distributed periodically along the root-tail direction. The maximum distance between each flocculent tooth 21a, 22a and the main body 10a is the tooth tip. The side of the tooth tip facing the tail direction is the flocculent flow side 211a, 221a, and the flocculent flow side 211a, 221a extends along the blade tail direction and gradually narrows towards the side of the main body 10a.

[0059] The side of the tooth tip facing the root direction is the rectifying side 212a, 222a, and the rectifying side 212a, 222a extends towards the root direction and gradually narrows towards the side of the main body 10a.

[0060] The flocculent teeth 21a, 22a are small tooth-shaped teeth, and the distance between each flocculent tooth and the main body gradually decreases along the root-tail direction, that is, the distance between the flocculent tooth 21a in front of the root and the main body 10a is greater than the distance between the flocculent tooth 22a in the tail direction and the main body 10a.

[0061] The blade is made of aluminum or its alloy.

[0062] The flocculent flow wing and the main body are integrally formed and fixed to each other.

[0063] Embodiment III

[0064] As Figure 9 and Figure 10 shown, it is a schematic structural diagram of the variable cross-section flocculent flow fan blade for large industrial use in this embodiment.

[0065] The blade of this embodiment includes a hollow main body 10b formed by extrusion. The main body 10b has an internal cavity along the root-to-tail direction of the blade, and the cavity is surrounded by the upper and lower surfaces of the main body. The upper and lower surfaces of the main body are arc-transitioned at the front side edge of the blade movement and gradually converge at the rear side of the blade movement.

[0066] The upper surface of the main body 10b is an arc-shaped surface from the front side to the rear side in the movement direction. Between the upper surface and the lower surface, the vertical distance in the middle is high, and the vertical distance on both sides is low. The upper surface and the lower surface gradually bend downward and converge at the rear side.

[0067] A support column connecting the upper and lower surfaces of the main body is provided inside the cavity. The column divides the cavity into a front chamber and a rear chamber along the front-rear direction of the movement. The lower surface of the main body starts to bend downward from the corresponding part of the rear chamber.

[0068] It also includes a solid flocculation flow wing 20b connected to the rear side edge of the blade and extending along the root-tail direction of the rear side edge. The upper and lower surfaces of the flocculation flow wing 20b are smoothly transitioned along the tangent direction with the upper and lower surfaces of the main body at the connection. The flocculation flow wing extends linearly backward from the connection with the main body. In other embodiments, it can also be arc-shaped extension.

[0069] At the rear side edge of the flocculation flow wing 20b, there are flocculation teeth 21b, 22b, 23b that are periodically and continuously distributed along the root-tail direction. The maximum distance between each flocculation tooth 21b, 22b, 23b and the main body is the tooth tip. The side of the tooth tip facing the tail direction is the flocculation flow side 211b, 221b, 231b. The flocculation flow sides 211b, 221b, 231b extend along the blade tail direction and gradually narrow towards the main body 10b side.

[0070] The side of the tooth tip facing the root direction is the rectifying side 212b, 222b, 232b. The rectifying sides 212b, 222b, 232b extend towards the root direction and gradually narrow towards the main body 10b side.

[0071] The flocculation teeth 21b, 22b are tooth-shaped small teeth. The distance between each flocculation tooth and the main body gradually decreases step by step along the root-tail direction. That is, each flocculation tooth is divided into several continuous groups along the root-tail direction. The distance between the flocculation teeth 21b, 22b within the group is the same. The distance between the flocculation tooth 23b in the group in the tail direction and the main body is less than the distance between the flocculation tooth 22b in the group in the root direction and the main body.

[0072] The blade is made of aluminum or its alloy.

[0073] The flocculation flow wing and the main body are integrally formed and fixed with each other.

[0074] Embodiment 4

[0075] As Figure 11 and Figure 12 shown, it is a schematic structural diagram of the variable cross-section flocculation flow fan blade for large industrial use in this embodiment.

[0076] The blade of this embodiment includes an extruded hollow main body 10c. The main body 10c has an internal cavity along the blade root to tail direction. The cavity is surrounded by the upper surface and the lower surface of the main body. The upper and lower surfaces of the main body are arc-transitioned at the front side edge of the blade movement and gradually converge at the rear side of the blade movement.

[0077] The upper surface of the main body 10c is an arc-shaped surface from the front side to the rear side in the movement direction. Between the upper surface and the lower surface, the vertical distance in the middle is high, and the vertical distance on both sides is low. The upper surface and the lower surface gradually bend downward and converge at the rear side.

[0078] Inside the cavity, there is a support column connecting the upper and lower surfaces of the main body. The column divides the cavity into a front chamber and a rear chamber along the front-rear direction of the movement. The lower surface of the main body starts to bend downward from the corresponding part of the rear chamber.

[0079] It also includes a solid flocculation flow wing 20c connected to the rear side edge of the blade and extending along the root-tail direction of the rear side edge. The upper and lower surfaces of the flocculation flow wing 20c are smoothly transitioned along the tangent direction with the upper and lower surfaces of the main body at the connection; the flocculation flow wing extends linearly backward from the connection with the main body. In other embodiments, it can also be arc-shaped extension.

[0080] At the rear side edge of the flocculation flow wing 20c, there are flocculation teeth 21c that are periodically and continuously distributed along the root-tail direction. The maximum distance between each flocculation tooth 21c and the main body 10c is the tooth tip. The side of the tooth tip facing the tail direction is the flocculation flow side 211c, and the flocculation flow side 211c extends along the blade tail direction and gradually narrows toward the main body 10c side.

[0081] The side of the tooth tip facing the root direction is the rectifying side 212c, and the rectifying side 212c extends toward the root direction and gradually narrows toward the main body 10c side.

[0082] The flocculation teeth 21c are large arc-shaped teeth, and the distance between each flocculation tooth and the main body gradually decreases along the root-tail direction, that is, the distance between the flocculation teeth in front of the root and the main body is greater than the distance between the flocculation teeth in the tail direction and the main body.

[0083] The blade is made of aluminum or its alloy.

[0084] The flocculation flow wing and the main body are integrally formed and fixed with each other.

[0085] Embodiment Five

[0086] As Figure 13 and Figure 14 shown, it is a schematic structural diagram of the variable cross-section flocculation flow fan blade for large industrial use in this embodiment.

[0087] The blade of this embodiment includes an extruded hollow main body 10d. The main body 10d has an internal cavity along the root-to-tail direction of the blade. The cavity is surrounded by the upper and lower surfaces of the main body; the upper and lower surfaces of the main body are arc-transitioned at the front side edge of the blade movement and gradually converge at the rear side of the blade movement.

[0088] The upper surface of the main body 10d is an arc-shaped surface from the front side to the rear side in the movement direction. Between the upper surface and the lower surface, the vertical distance in the middle is high, and the vertical distance on both sides is low. The upper surface and the lower surface gradually bend downward and converge at the rear side.

[0089] Inside the cavity, there is a support column connecting the upper and lower surfaces of the main body. The column divides the cavity into a front chamber and a rear chamber in the front-back direction of the movement. The lower surface of the main body starts to bend downward from the corresponding part of the rear chamber.

[0090] It also includes a solid flocculation flow wing 20d connected to the rear side edge of the blade and extending along the root-tail direction of the rear side edge. The upper and lower surfaces of the flocculation flow wing 20d are smoothly transitioned along the tangent direction with the upper and lower surfaces of the main body at the connection. The flocculation flow wing extends linearly backward from the connection with the main body. In other embodiments, it can also be arc-shaped extension.

[0091] At the rear side edge of the flocculation flow wing 20d, there are flocculation teeth 21d that are periodically and continuously distributed along the root-tail direction. The maximum distance between each flocculation tooth 21d and the main body 10d is the tooth tip. The side of the tooth tip facing the tail direction is the flocculation flow side 211d. The flocculation flow side 211d extends along the blade tail direction and gradually narrows toward the main body 10d side.

[0092] The side of the tooth tip facing the root direction is the rectifying side 212d. The rectifying side 212d extends toward the root direction and is flush with one side of the main body 10d. The rectifying side 212d that is flush with one side of the main body and the corresponding part of the flocculation flow wing 20d form a rectifying plate.

[0093] The flocculation teeth 21d are stepped large teeth. The distance between each flocculation tooth and the main body gradually decreases along the root-tail direction, that is, the distance between the flocculation teeth in front of the root and the main body is greater than the distance between the flocculation teeth in the tail direction and the main body.

[0094] The blade is made of aluminum or its alloy.

[0095] The flocculation flow wing and the main body are integrally formed and fixed.

[0096] Principle and effect description.

[0097] As Figure 15 and Figure 16 shown, Figure 15 is the wind force density distribution diagram of the equal cross-section blade in the prior art, Figure 16 is the wind force density distribution diagram of the variable cross-section blade of the present invention. From the two figures, it can be seen that the wind force in the center of the blade in the prior art is relatively sparse, and the wind force is much weaker than that of the surrounding area and is uneven. The blade of the present invention improves the above problems, the wind force in the center has been improved, and the wind force distribution is relatively balanced.

[0098] As Figure 17 and Figure 18As shown in the figure, this is a wind force cutting schematic diagram of the variable cross-section turbulent flow wing of the present invention (this is a simplified schematic diagram). From the trend of the cross-sectional dimensions of the turbulent flow wing, overall, the root direction of the fan is larger and the tail direction is smaller, or it changes periodically, thus balancing the disadvantage of insufficient linear velocity and weak wind force at the root of the fan, making the wind force difference between the root and tail of the blade smaller. In addition, the turbulences on the turbulent flow wing cut the wind force and disrupt it regularly. The turbulences are arranged periodically, forming periodic wind force fluctuations behind the blade. The diffusion of the wind force fluctuations interferes with the wind force fluctuations of other turbulences to form a turbulent flow, which will form a gust effect with changes in strength and direction within a large range below the fan, thus simulating natural wind; the blowing of natural wind will be more comfortable than that of a fan.

[0099] As described above, the above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims. According to the disclosure and teachings of the above specification, those skilled in the art of the present invention can also make changes and modifications to the above implementation manner. Therefore, the present invention is not limited to the specific implementation manner disclosed and described above, and some modifications and changes to the invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A variable cross-section turbulent flow fan blade for large industrial use, the blade comprising a hollow main body formed by extrusion, the main body having an internal cavity along the direction from the blade root to the tail, the cavity being surrounded by the upper and lower surfaces of the main body; the upper and lower surfaces of the main body are arc-transitioned at the front side of the blade movement and gradually converge at the rear side of the blade movement; characterized in that, the upper surface of the main body is an arc surface from the front side to the rear side of the movement direction, and between the upper surface and the lower surface, the vertical distance in the middle is high and the vertical distance on both sides is low, and the upper surface and the lower surface gradually bend downward and converge at the rear side; it further comprises a solid turbulent flow wing connected to the rear side of the blade and extending along the root-tail direction of the rear side, and the upper and lower surfaces of the turbulent flow wing are smoothly transitioned along the tangent direction with the upper and lower surfaces of the main body at the connection; at the rear side of the turbulent flow wing, there are turbulator teeth continuously distributed periodically along the root-tail direction, each turbulator tooth at least comprising a turbulent flow edge extending along the root-tail direction and gradually narrowing towards the main body side; the distance between each turbulator tooth and the main body gradually becomes smaller along the root-tail direction; the position with the largest distance between each turbulator tooth and the main body is the tooth tip, and the side of the tooth tip towards the tail direction is the said turbulent flow edge; the side of the tooth tip towards the root direction is the rectifying edge, and the rectifying edge extends towards the root direction and is flush with one side of the main body; the rectifying edge flush with one side of the main body and the corresponding turbulent flow wing part form a rectifying plate.

2. The blade according to claim 1, wherein, The turbulator teeth are stepped large teeth.

3. The blade according to claim 1, characterized in that, A support column connecting the upper and lower surfaces of the main body is arranged inside the cavity, and the column divides the cavity into a front chamber and a rear chamber along the front-rear direction of the movement, and the lower surface of the main body starts to bend downward from the corresponding part of the rear chamber.

4. The blade according to claim 1, characterized in that, The turbulent flow wing extends linearly or in an arc from the connection with the main body towards the rear side.

5. The blade according to claim 1, characterized in that, The blade is made of aluminum or its alloy.

6. The blade according to claim 1, wherein The turbulent flow wing and the main body are integrally formed and fixed or assembled and fixed with each other.

7. The blade according to claim 1, characterized in that, The length of the blade is 2m to 10m.

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