A blade assembly for a centrifugal fan

Abstract

This invention proposes a blade assembly for a centrifugal fan. The blade assembly includes a blade base and a blade body. The blade base is disposed within the inlet duct of the centrifugal fan and is connected to the fan's rotating shaft. The axial direction of the rotating shaft, the axial direction of the inlet duct, and the axial direction of the blade base coincide. The blade body is connected to the blade base and located on the side of the blade base adjacent to the inlet of the inlet duct. In a plane orthogonal to the axial direction of the rotating shaft, the first end of the blade body is flush with the edge of the blade base, and the second end of the blade body is spaced apart from the rotating shaft. There are multiple blade bodies, which are arranged circumferentially along the rotating shaft. The blade assembly for a centrifugal fan of this invention has the advantage of good anti-clogging effect.

Description

Technical Field

[0001] This invention belongs to the field of centrifugal fan technology, specifically, it relates to a blade assembly for a centrifugal fan. Background Technology

[0002] Retired wind turbine blades are mainly composed of glass fiber reinforced plastic (GFRP) and thermosetting resin (such as unsaturated polyester resin), with glass fiber accounting for approximately 60% to 70% and resin matrix accounting for approximately 25% to 35%. Related technologies often employ a combination of blade tearing and hammer crushing to break the long glass fibers in the blades into short glass fibers less than 20mm in length, generating other powdery substances. During the conveying process using ordinary centrifugal fans, these short, needle-like glass fibers easily bridge between the inlet blades of the centrifugal fan, forming a mesh structure. This leads to the continuous adhesion of powdery resin to the mesh structure, eventually completely clogging the centrifugal fan inlet, affecting the conveying of the broken wind turbine blades, and causing the production line to stop operating. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention provide a blade assembly for a centrifugal fan, which has the advantage of good anti-clogging effect.

[0005] The blade assembly for a centrifugal fan according to an embodiment of the present invention includes:

[0006] The centrifugal fan comprises a blade base and a blade body. The blade base is located within the inlet duct of the centrifugal fan and is connected to the rotating shaft of the centrifugal fan. The axial direction of the rotating shaft, the axial direction of the inlet duct, and the axial direction of the blade base coincide. The blade body is connected to the blade base and is located on the side of the blade base adjacent to the inlet of the inlet duct. In a plane orthogonal to the axial direction of the rotating shaft, the first end of the blade body is flush with the edge of the blade base, and the second end of the blade body is spaced apart from the rotating shaft. There are multiple blade bodies, which are arranged circumferentially along the rotating shaft.

[0007] In this embodiment of the invention, the second end of the blade body of the blade assembly for a centrifugal fan is spaced apart from the rotating shaft, forming a bladeless axial channel in the central region of the inlet duct. This avoids severe shearing and agitation at the blade tips, reducing the chance of glass fibers being forcibly entangled or hooked in the central region. It effectively prevents blockage at the centrifugal fan inlet, ensuring continuous and stable operation of the conveyor line and reducing unplanned downtime caused by blockages.

[0008] In some embodiments, a retaining ring is further included, the retaining ring being connected to the blade base, the rotating shaft passing through the blade base and connected to the retaining ring, and the second end of the blade body being arranged adjacent to the outer peripheral wall of the retaining ring.

[0009] In some embodiments, in a plane orthogonal to the axis of rotation, the projected area of ​​the retaining ring is approximately equal to the projected area of ​​the inlet of the inlet duct.

[0010] In some embodiments, the blade base and the inlet of the inlet duct are arranged axially spaced on the rotating shaft.

[0011] In some embodiments, the cross-sectional area of ​​the second end of the blade body gradually increases in the direction from the axis of rotation to the blade body.

[0012] In some embodiments, the second end of the blade body has a generally inclined sidewall away from the blade base.

[0013] In some embodiments, the second end of the blade body has a generally convex arc surface on the sidewall away from the blade base.

[0014] In some embodiments, the cross-sectional area of ​​the blade body gradually decreases along the direction from the blade base to the blade body.

[0015] In some embodiments, the blade body is welded to the blade base.

[0016] In some embodiments, the blade body and the blade base are integrally formed. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a blade assembly for a centrifugal fan according to an embodiment of the present invention.

[0018] Figure 2 This is a partial structural schematic diagram of a blade assembly for a centrifugal fan according to an optional embodiment of the present invention.

[0019] Figure label: 100. Inlet air duct; 101. Inlet; 200. Rotary shaft. 1. Blade base, 2. Blade body, 21. First end, 22. Second end, 3. Fixing ring. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] like Figure 1 and Figure 2 As shown, the blade assembly for a centrifugal fan according to an embodiment of the present invention includes a blade base 1 and a blade body 2. The blade base 1 is disposed in the inlet duct 100 of the centrifugal fan and is connected to the rotating shaft 200 of the centrifugal fan. The axial direction of the rotating shaft 200, the axial direction of the inlet duct 100, and the axial direction of the blade base 1 coincide. The blade body 2 is connected to the blade base 1 and is located on the side of the blade base 1 adjacent to the inlet 101 of the inlet duct 100. In a plane orthogonal to the axial direction of the rotating shaft 200, the first end 21 of the blade body 2 is flush with the edge of the blade base 1, and the second end 22 of the blade body 2 is spaced apart from the rotating shaft 200. There are multiple blade bodies 2, which are arranged at intervals along the circumference of the rotating shaft 200.

[0022] Specifically, such as Figure 1 As shown, the center of the blade base 1 is directly connected to the shaft 200 of the centrifugal fan. That is, when the centrifugal fan motor drives the shaft 200 to rotate, the entire blade assembly (including the base and all blade bodies 2) will rotate at high speed. This connection ensures power transmission. Multiple blade bodies 2 are fixedly connected to the blade base 1 and located on the side of the base adjacent to the inlet 101 of the inlet duct 100. These multiple blade bodies 2 are designed to directly face the direction of material entry and are the first components to contact and act upon the material flow.

[0023] Understandably, when viewed in a plane perpendicular to the axis of rotation 200 (i.e., radial section), the design of each blade body 2 has two key features: the first end 21 of the blade body 2 is flush with the edge of the blade base 1. This allows the blade body 2 to maximize the utilization of the effective flow diameter of the air duct, transmitting the rotational disturbance effect to the entire annular area of ​​the air duct inlet; the second end 22 of the blade body 2 is spaced apart from the axis of rotation 200, meaning the blade body 2 does not extend to the center of the axis of rotation 200. This creates a circular open space free from blade disturbance in the central inlet region.

[0024] In other words, multiple blade bodies 2 are arranged circumferentially (i.e. radially) along the axis of rotation 200. This arrangement forms multiple "defense lines" to ensure that materials at different locations in the airflow direction are effectively stirred and guided, preventing the formation of a stable accumulation layer of materials in a certain cross section along the axial direction.

[0025] In this embodiment of the invention, the second end 22 of the blade body 2 of the blade assembly for a centrifugal fan is spaced apart from the rotating shaft 200, forming a bladeless axial channel in the central region of the inlet duct 100. This avoids severe shearing and agitation at the blade tips, reducing the chance of glass fibers being forcibly entangled or hooked in the central region. It effectively prevents blockage at the centrifugal fan inlet, ensuring continuous and stable operation of the conveyor line and reducing unplanned downtime caused by blockages.

[0026] In some embodiments, a fixing ring 3 is also included, which is connected to the blade base 1. The rotating shaft 200 passes through the blade base 1 and is connected to the fixing ring 3. The second end 22 of the blade body 2 is arranged adjacent to the outer peripheral wall of the fixing ring 3.

[0027] Specifically, such as Figure 1 As shown, the retaining ring 3, as an independent annular component, is directly connected to the blade base 1. The connection between the retaining ring 3 and the blade base 1 is typically a fixed connection, such as welding or bolt fastening, ensuring that the two form a rigid whole under high-speed rotation. Preferably, the retaining ring 3 and the blade base 1 are fastened together by bolts.

[0028] It is understandable that one end of the rotating shaft 200 passes through the blade base 1 and is connected to the fixed ring 3 through the bearing. The fixed ring 3 is located on the side of the blade base 1 near the inlet 101. After long-term use, the material entering the centrifugal fan may stick to the fixed ring 3. Since the fixed ring 3 is connected to the blade base 1 by bolts, after long-term use, the material accumulation on the blade assembly can be reduced by replacing the fixed ring 3, thus ensuring the normal operation of the centrifugal fan.

[0029] In some embodiments, in a plane orthogonal to the axial direction of the rotating shaft 200, the projected area of ​​the retaining ring 3 is approximately equal to the projected area of ​​the inlet 101 of the inlet duct 100.

[0030] It is understandable that, such as Figure 1 As shown, the fixed ring 3 matches the projected area of ​​the inlet 101 of the inlet duct 100, which helps ensure that the airflow can enter the duct smoothly and unobstructed, reducing airflow separation and vortex formation. The design of matching the area of ​​the fixed ring 3 with the inlet 101 of the inlet duct 100 helps to optimize the structure of the blade assembly, making it more in line with the aerodynamic design requirements of the fan.

[0031] In some embodiments, the blade base 1 and the inlet 101 of the inlet duct 100 are arranged axially on the rotating shaft 200 at intervals.

[0032] Specifically, such as Figure 1As shown, the blade base 1 and the inlet 101 of the inlet duct 100 are spaced apart, creating a certain space between the inlet 101 and the blade assembly. Depending on the centrifugal fan's structure, the distance between the blade base 1 and the inlet 101 can be appropriately adjusted to ensure stable and smooth airflow through the inlet 101. In other words, this spacing establishes an effective labyrinth seal or airflow seal between the rotating components and the duct, helping to prevent material backflow or maintain negative system pressure, while also increasing operational safety.

[0033] Understandably, the spacing between the blade base 1 and the inlet 101 of the inlet duct 100 optimizes the airflow distribution within the inlet duct 100, reducing turbulence and eddies as the airflow enters the fan, thereby improving fan efficiency. This spacing also facilitates maintenance of the blade base 1 and blade body 2, allowing for easier access and replacement of individual blades or blade bases 1. Furthermore, this design can accommodate different types of fan designs, including inlet ducts 100 of varying sizes and shapes, and different numbers of blades.

[0034] Optionally, the blade base 1 is moved rearward relative to the inlet 101 of the inlet duct 100, providing valuable axial space for the installation of observation windows, maintenance doors, foreign object cleaning ports, and sensors (such as level gauges and blockage detectors) that may be needed at the inlet end, without worrying about interference with the rotating components.

[0035] In some embodiments, the cross-sectional area of ​​the second end 22 of the blade body 2 gradually increases along the direction from the rotation axis 200 to the blade body 2.

[0036] Specifically, such as Figure 1 As shown, the cross-sectional area of ​​the second end 22 of the blade body 2 gradually increases along the direction from the rotating shaft 200 to the blade body 2, so that the space formed between the blade body 2 at the second end 22 and the fixing ring 3 gradually increases, avoiding the blade body 2 from extending directly to the position of the rotating shaft 200, thereby optimizing the flow path of the airflow on the blade body 2.

[0037] Understandably, the gradual increase in the cross-sectional area of ​​the second end 22 of the blade body 2 helps to guide the airflow to flow more smoothly on the blade body 2, reduce airflow separation and vortex formation, thereby improving the aerodynamic efficiency of the fan.

[0038] In some embodiments, the second end 22 of the blade body 2, away from the blade base 1, is generally inclined (not shown in the figure).

[0039] Understandably, the second end 22 of the blade body 2, away from the sidewall of the blade base 1, is designed as an inclined surface. This inclined surface can be uniform or gradually changing. With multiple inclined surfaces at the second end 22 of multiple blade bodies 2 around the rotation shaft 200, the design of multiple inclined surfaces forms an airflow channel. When the airflow passes through this channel, it will be guided and accelerated by the inclined surfaces.

[0040] In other words, the thickness of the inner tip of the blade gradually increases radially outward from its thinnest or sharpest point, eventually transitioning smoothly to the thickness of the main body of the blade. The inner tip of the blade can be machined into a streamlined blunt nose similar to the leading edge of an airfoil, or a trapezoidal or teardrop-shaped cross-section, with the smallest cross-sectional area at its innermost point, rapidly expanding radially.

[0041] In other words, the design with a gradually increasing cross-sectional area results in a smooth, blunt, streamlined surface with a large radius of curvature at the inner end of the blade, rather than a sharp edge. When material entering from inlet 101 encounters this smooth convex surface, it is more likely to be deflected or slide along the surface, rather than being hooked or pierced. Even if a small number of fibers attempt to adhere, because the surface is a continuously changing curved surface with an increasing cross-sectional area, the fibers cannot find a stable point of attachment to form a strong entanglement, and are more easily peeled off under the action of airflow and centrifugal force.

[0042] Optionally, the sidewall of the second end 22 of the blade body 2 away from the blade base 1 is generally a convex arc surface.

[0043] It is understandable that, such as Figure 1 As shown, the sidewall away from the blade base 1 refers to the leading edge surface or inlet surface of the second end 22 of the blade. In the direction of rotation, this is the side of the blade that first faces the airflow and incoming material (non-driving surface). That is, the convex arc surface is one of the most hydrodynamically optimal shapes among all the windward surfaces facing the incoming flow. It can separate the oncoming fluid (including airflow carrying fibers and powder) to both sides with minimal resistance and in the smoothest manner.

[0044] In other words, when material clumps or dense fiber flows rush towards the blade, the convex surface prevents them from "colliding" with a flat surface. Instead, it guides them to slide naturally along the curved surface towards both sides of the blade (i.e., the channel between adjacent blades). Smooth convex surfaces (especially streamlined shapes with continuously varying curvature) can most effectively adhere to the airflow, delaying or eliminating flow separation. The streamlines at the blade leading edge become extremely smooth, generating almost no low-speed eddies. This makes it difficult for fine resin powder and short fibers to remain there, achieving surface self-cleaning and suppressing the risk of gradual thickening of deposits on the blade body 2 surface.

[0045] In some embodiments, the cross-sectional area of ​​the blade body 2 gradually decreases along the direction from the blade base 1 to the blade body 2.

[0046] It is understandable that, such as Figure 2 As shown, the direction from the blade base 1 to the blade body 2 refers to the direction extending from the root of the blade to the base, along the blade towards the outer edge (or tip) of the air duct. This is usually the spanwise direction of the blade (radially outward). Along this outward extending direction, the cross-sectional area of ​​the blade body 2 gradually decreases, that is, the thickness of the blade body 2 gradually decreases from the root to the tip.

[0047] In other words, when the blade rotates at high speed, the centrifugal force accumulates linearly from the root to the tip, with the root bearing the greatest tensile stress. The blade body 2 adopts a structure with a cross-section that gradually decreases from the inside to the outside, which perfectly matches the distribution of centrifugal force. The root cross-section is the largest to withstand the greatest stress, while the tip cross-section is the smallest to match the smaller stress.

[0048] This achieves an approximately uniform stress distribution, avoiding material redundancy or localized overload, and enabling structural lightweighting while ensuring strength and safety factor. It also reduces the risk of fatigue fracture at the blade root or center due to stress concentration, making it suitable for handling applications involving impact-sensitive materials.

[0049] Of course, the tapered streamlined anti-adhesion structure of the blade body 2 enhances the anti-adhesion optimization capability of the entire blade surface, ensuring long-term structural integrity under harsh operating conditions. From the central open area at the inlet and the flow guide of the fixed ring 3 to the streamlined design of the blade body 2 itself, a low-resistance, efficient, and stable pneumatic conveying environment is formed.

[0050] In some embodiments, the blade body 2 is welded to the blade base 1.

[0051] Understandably, the crushed material may contain incompletely broken hard glass fiber blocks or foreign objects, which can cause random impacts on the blades. At the same time, the blades rotate at high speed and are subjected to enormous centrifugal forces, with the root connection experiencing the greatest stress. The continuous, full-penetration weld formed by welding can achieve a connection with the base material of equal or even greater strength, providing stiffness and fatigue resistance far exceeding that of bolted or riveted connections.

[0052] In other words, the joint surface between the blade body 2 and the blade base 1, which is bolted or riveted, will have minute gaps, bolt heads, or nut protrusions. These areas are highly susceptible to becoming starting points for fiber entanglement and "nests" for resin powder accumulation. Simultaneously, high-speed dust can cause severe erosion and wear on these protrusions. High-quality welding allows the weld area to be ground to a smooth transition with the base material, forming a continuous, smooth, and uninterrupted fluid contact surface. This ensures that the blade root area (one of the most prone to bridging) has no mechanical interface gaps that allow fibers to hook or powder to penetrate, thus fully realizing the anti-sticking effects of the aforementioned "convex arc surface" and "smooth surface" designs. The smooth surface reduces localized turbulence and particle impact, improving the area's resistance to erosion and wear.

[0053] Optionally, the blade body 2 and the blade base 1 are integrally formed.

[0054] It is understandable that the integral molding of the blade body 2 and the blade base 1 means that the blade body 2 and the blade base 1 are not two independent parts connected in some way, but rather a single part with a complete and continuous material structure directly formed from the same raw material during the manufacturing process through processing (such as casting, forging, integral CNC milling, 3D printing additive manufacturing). This means that there is no physical connection interface or seam between the blade body 2 and the blade base 1; they are completely continuous in terms of material and structure.

[0055] In other words, a one-piece molded surface (especially one obtained through precision machining or forging) can achieve a completely smooth transition from the leading edge of the blade's convex arc to the root and then to the base surface, without any steps, gaps, or material discontinuities. Fibers and powder encounter an "absolutely smooth and seamless wall," with no physical "breakthrough" to form initial adhesion or entanglement. This pushes all previous claims about smooth surfaces, convex arc designs, and gap elimination to a theoretically achievable physical peak. The completely uniform material properties of the surface result in more even wear, avoiding grooved selective wear caused by differences in hardness / wear resistance between the weld and the base material.

[0056] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0058] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0060] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A blade assembly for a centrifugal fan, characterized in that, include: The centrifugal fan comprises a blade base and a blade body. The blade base is located inside the centrifugal fan and is connected to the rotating shaft of the centrifugal fan. The axial direction of the rotating shaft, the axial direction of the inlet duct, and the axial direction of the blade base coincide. The blade body is connected to the blade base and is located on the side of the blade base adjacent to the inlet of the inlet duct. In a plane orthogonal to the axial direction of the rotating shaft, the first end of the blade body is flush with the edge of the blade base, and the second end of the blade body is spaced apart from the rotating shaft. There are multiple blade bodies, which are arranged circumferentially along the rotating shaft.

2. The blade assembly for a centrifugal fan according to claim 1, characterized in that, It also includes a fixing ring, which is connected to the blade base. The rotating shaft passes through the blade base and is connected to the fixing ring. The second end of the blade body is arranged adjacent to the outer peripheral wall of the fixing ring.

3. The blade assembly for a centrifugal fan according to claim 2, characterized in that, In a plane orthogonal to the axis of the rotating shaft, the projected area of ​​the fixed ring is approximately equal to the projected area of ​​the inlet of the inlet air duct.

4. The blade assembly for a centrifugal fan according to claim 2, characterized in that, The blade base and the inlet of the inlet air duct are arranged axially on the rotating shaft at intervals.

5. The blade assembly for a centrifugal fan according to claim 1, characterized in that, Along the direction from the axis of rotation to the blade body, the cross-sectional area of ​​the second end of the blade body gradually increases.

6. The blade assembly for a centrifugal fan according to claim 5, characterized in that, The second end of the blade body has a generally inclined sidewall away from the blade base.

7. The blade assembly for a centrifugal fan according to claim 5, characterized in that, The second end of the blade body, away from the blade base, has a generally convex arc surface on its sidewall.

8. The blade assembly for a centrifugal fan according to claim 5, characterized in that, Along the direction from the blade base to the blade body, the cross-sectional area of ​​the blade body gradually decreases.

9. The blade assembly for a centrifugal fan according to claim 1, characterized in that, The blade body is welded to the blade base.

10. The blade assembly for a centrifugal fan according to claim 1, characterized in that, The blade body and the blade base are integrally formed.

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