Blades, fan wheels and injection molds

Abstract

This invention relates to blades, fan impellers, and injection molds for agricultural and livestock applications. The blade includes a plastic body extending from the blade root to the blade tip in the span direction. This plastic body has a concave-convex airfoil profile whose shape, size, and orientation vary along the span direction. The chord length of the concave-convex airfoil profile increases from a first chord length value at the blade root to a second chord length value at a first intermediate blade segment between the blade root and the blade tip, and decreases from the second chord length value at the first intermediate blade segment to a third chord length value at the blade tip, where the third chord length value is less than the first chord length value. The angle of attack of the concave-convex airfoil profile decreases from a first angle value at the blade root to a second angle value at the blade tip. Using this solution, the desired exact blade size can be obtained using only a modular injection mold, eliminating the need to first manufacture a larger blade and then cut it, which would result in waste.

Description

Technical Field

[0001] This utility model relates to a blade for a fan impeller used in agricultural and livestock applications. Background Technology

[0002] Existing fan impellers are used in environments requiring reliable airflow, such as agricultural and livestock facilities. Typically, these impellers consist of multiple blades arranged around a central hub, with the blades usually manufactured from polymeric materials through injection molding. Design considerations encompass aerodynamic efficiency, structural integrity, and the ability to withstand varying operating loads. In many installations, impeller performance has a direct impact on environmental control objectives, including temperature regulation, humidity management, and energy consumption. Therefore, blade geometry and manufacturing precision are critical factors in ensuring that the fan meets the volumetric flow rate and pressure characteristics required by the end user.

[0003] Market expectations for ventilation and air handling systems continue to evolve, driven by increasingly stringent ecological regulations and a global focus on energy efficiency. End users seek fan components capable of maintaining high volumetric airflow with minimal energy input under a wide range of operating conditions. Simultaneously, manufacturers pursue cost-effective production strategies aimed at reducing processing complexity and material waste. Challenges include meeting directional flow requirements under elevated pressures, maintaining stable performance under fluctuating loads, and adhering to lifecycle sustainability goals. A versatile solution would ideally harmonize aerodynamic performance with a streamlined manufacturing process, adapting to diverse installation environments without incurring excessive processing or operating costs.

[0004] Despite advancements in aerodynamic modeling and manufacturing techniques, many existing blade configurations exhibit significant sensitivity to changes in operating pressure. In fact, blade profiles optimized for a specific diameter and pressure range often become ineffective when conditions change, leading to reduced airflow or decreased efficiency. Furthermore, traditional blade sizing methods typically require different molds for each impeller diameter or trimming after the production of very large components, resulting in increased capital expenditure and material waste.

[0005] More specifically, agricultural and livestock applications place stringent demands on impeller assemblies, requiring reliable performance across diameters typically ranging from fifty to sixty inches. In such applications, even slight deviations in blade geometry can lead to suboptimal pressure profiles or reduced energy efficiency, undermining regulatory compliance and operational cost objectives. Manufacturers currently face a trade-off: either invest in multiple dedicated die-cutting tools to cover each size increment, or accept the inefficiencies and waste associated with trimming from larger blanks. This dilemma underscores the urgent need for blade solutions capable of addressing variable impeller diameters and pressure ranges without incurring excessive manufacturing complexity or aerodynamic performance losses. Utility Model Content

[0006] The purpose of this invention is to provide a blade for a fan impeller that can at least partially overcome the aforementioned disadvantages. Another purpose of this invention is to provide a mold for blade production that can at least partially overcome the aforementioned disadvantages.

[0007] These objectives have been achieved through a blade, a fan impeller for agricultural and livestock applications, comprising a plastic body extending from the blade root to the blade tip in the span direction, the plastic body having an airfoil profile whose shape, size, and orientation vary along the span direction, wherein the chord length of the airfoil profile increases from a first chord length value at the blade root to a second chord length value at a first intermediate blade segment between the blade root and the blade tip, and decreases from the second chord length value at the first intermediate blade segment to a third chord length value at the blade tip, the third chord length value being less than the first chord length value, wherein the angle of attack of the airfoil profile decreases from a first angle value at the blade root to a second angle value at the blade tip.

[0008] Preferably, the first intermediate leaf segment is positioned closer to the leaf root than to the leaf tip.

[0009] Preferably, the first chord length is between 166 mm and 206 mm, the second chord length is between 192 mm and 242 mm, and the third chord length is between 102 mm and 141 mm.

[0010] Preferably, the first angle value is between 32° and 46°, and the second angle value is between 11.5° and 15.5°.

[0011] The aforementioned objective has also been achieved by a fan impeller for agricultural and livestock applications, comprising an impeller hub and a plurality of blades extending from the impeller hub, wherein each of the plurality of blades comprises a plastic body extending radially from the blade root to the blade tip, the plastic body having an airfoil profile whose shape, size, and orientation vary radially, wherein the chord length of the airfoil profile increases from a first chord length value at the blade root to a second chord length value at a first intermediate blade segment between the blade root and the blade tip, and decreases from the second chord length value at the first intermediate blade segment to a third chord length value at the blade tip, the third chord length value being less than the first chord length value, wherein the angle of attack of the airfoil profile decreases from a first angle value at the blade root to a second angle value at the blade tip.

[0012] Preferably, the first intermediate leaf segment is positioned closer to the leaf root than to the leaf tip.

[0013] Preferably, the first chord length is between 166 mm and 206 mm, the second chord length is between 192 mm and 242 mm, and the third chord length is between 102 mm and 141 mm.

[0014] Preferably, the first angle value is between 32° and 46°, and the second angle value is between 11.5° and 15.5°.

[0015] The aforementioned objective has also been achieved by an injection mold for producing blades according to the present invention, wherein the injection mold includes a first mold component and a second mold component, the first mold component and the second mold component being configured to be connected to each other to define a main mold cavity therebetween conforming to the blade to be produced, the main mold cavity being configured to be filled with molten plastic material, wherein a first seat is formed in the first mold component for receiving a first insert component, and a second seat is formed in the second mold component for receiving a second insert component, wherein the first insert component and the second insert component are configured to be connected to each other to define an end mold cavity therebetween, fluidly connected to the main mold cavity and conforming to the end portion of the blade to be produced.

[0016] This solution allows for the precise blade size to be obtained using only modular injection molds, eliminating the need to manufacture a larger blade first and then cut it, which would otherwise result in waste. Attached Figure Description

[0017] Further features and advantages of the blade according to the present invention will become clearer from the following detailed description of embodiments of the present invention with reference to the accompanying drawings, which are provided for illustrative and non-limiting purposes only, in which:

[0018] Figure 1a This is a perspective view of one embodiment of the fan;

[0019] Figure 1b This is a perspective view of the fan impeller of the fan in Figure 1;

[0020] Figure 2 yes Figure 1b A side view of the blades of the fan impeller in the image;

[0021] Figures 3 to 8 These are intercepts taken along lines III-III, IV-IV, VV, VI-VI, VII-VII, and VIII-VIII, respectively. Figure 2 A cross-sectional view of the blades;

[0022] Figure 9 and Figure 10These are perspective views of a first mold component and a second mold component, respectively, configured to be connected to each other to form an injection mold for producing blades according to the present invention.

[0023] Figure 11 and Figure 12 They are to be installed to Figure 9 and Figure 10 Perspective view of the insert component of the mold part in the assembly configuration and the separation configuration. Detailed Implementation

[0024] Figure 1a A fan is shown, typically comprising a fan impeller 20 rotatably supported within a housing or shroud 30, and driven to rotate by an electric motor 40. The axis of rotation of the impeller 20 is... Figure 1b The 'z' symbol is used in Chinese.

[0025] The fan may also include a duct 50 connected to the housing 30. The housing 30 defines an airflow passage having an inlet and an outlet located upstream and downstream of the fan impeller 20, respectively. The fan may also include a shutter 60. According to other embodiments, the fan may include a damper or other mechanical means operable to regulate or control airflow.

[0026] The fan impeller 20 includes an impeller hub 21 and a plurality of blades 22 extending radially outward from the impeller hub 21.

[0027] Figures 2 to 8 One of the plurality of blades 22 is shown. The blade 22 includes a plastic body 23 extending in a span direction r, which corresponds to a radial direction relative to the axis of rotation z of the fan impeller 20 when the blade 22 is mounted in the fan impeller 20.

[0028] The plastic body 23 extends from the blade root 23a to the blade tip 23b in the span direction r. The plastic body 23 includes a shank 23c at the blade root 23a, configured for connection to the impeller hub 21. The plastic body 23 has a concave-convex airfoil profile 24 whose shape, size, and orientation vary along the span direction r. "Concave-convex" means that the airfoil profile is defined between a recessed front surface profile 24a and a convex rear surface profile 24b. Figures 3 to 8 In the middle, the direction of movement of blade 22 is parallel to the horizontal direction.

[0029] The chord length of the concave-convex airfoil profile 24 is defined as the distance measured from the leading edge 24c to the trailing edge 24d of the concave-convex airfoil profile 24. The chord length is derived from... Figure 3 The first chord length CL1 at the leaf root 23a shown increases to, as... Figure 4The second chord length CL2 is shown at the first intermediate leaf segment 23e between the leaf root 23a and the leaf tip 23b. Furthermore, the chord length CL decreases from the second chord length CL2 at the first intermediate leaf segment 23e to... Figure 8 The third chord length CL3 at the blade tip 23b is shown. The third chord length CL3 is less than the first chord length CL1. Figures 5 to 7 The figure shows additional intermediate segments located between the first intermediate leaf segment 23e and the leaf tip 23b. In these additional intermediate segments, the chord lengths are indicated by chord length values ​​CL4, CL5, and CL6, respectively. Preferably, the first intermediate leaf segment 23e is positioned closer to the leaf root 23a than to the leaf tip 23b. The first intermediate leaf segment 23e can be located at a distance from the leaf root 23a, between approximately one-quarter and one-sixth of the leaf span length SL. In the figure, the first intermediate leaf segment 23e and... Figures 5 to 7 The other intermediate segments shown are roughly equidistant from each other.

[0030] The angle of attack of the concave-convex airfoil profile 24 is defined as the angle between the chord line on the concave-convex airfoil profile 24 and the relative wind direction. Figures 3 to 8 The angle between the horizontal direction (as shown in the image). Angle of attack from... Figure 3 The first angle value α1 at the leaf root 23a shown is reduced to, as Figure 8 The second angle value α2 is shown at the blade tip 23b. Figures 4 to 7 In the intermediate section shown, the angle of attack is indicated by values ​​α3, α4, α5, and α6 respectively.

[0031] For an impeller diameter of 55'' (corresponding to 139.7 cm), the chord length and angle values ​​can be:

[0032] CL1 (leaf base) = 187 ± 19 mm α1 (leaf base) = 42° ± 4°

[0033] CL2 (first intermediate lobe segment) = 220±22 mm α3 = 30°±3°

[0034] CL4 = 185±19 mm α4 = 22°±2°

[0035] CL5 = 149±15 mm α5 = 17°±1.5°

[0036] CL6 = 132±13 mm α6 = 15°±1.5°

[0037] CL3 (blade tip) = 123 ± 12 mm α2 (blade tip) = 14° ± 1.5°

[0038] Typically, the first chord length CL1 can be between 166 mm and 206 mm, the second chord length CL2 can be between 192 mm and 242 mm, and the third chord length CL3 can be between 102 mm and 141 mm. The first angle value α1 can be between 32° and 46°, and the second angle value α2 can be between 11.5° and 15.5° (the extreme values ​​of the above ranges are also covered by this invention). Through these measures, the size of the fan impeller 20 can cover a diameter range from 50'' to 60'' (i.e., from 127 cm to approximately 152.4 cm). The blades 22 are made of plastic polymer and are produced by injection molding technology.

[0039] The blade shape can be developed using computational fluid dynamics (CFD) analysis, with the center dimension (55'') of the series of sizes as the design focus, and other dimensions optimized at the design level based on the following variations:

[0040] - For larger diameters, extend the span length of the blades;

[0041] - For smaller diameters, cut the blade at the base or tip.

[0042] This allows for the retention of a "central core" that is universal across all sizes, from which all other forms can be derived using removable "accessories." With this solution, the exact desired blade size can be obtained using only modular injection molding, eliminating the need to first manufacture a larger blade and then cut it, which would otherwise result in waste.

[0043] Figure 9 and Figure 10 A first mold component 100 and a second mold component 200 are shown, together forming an injection mold for producing a blade according to the above description. The first mold component 100 and the second mold component 200 are configured to be coupled to each other to define a main mold cavity therebetween, which conforms to the blade to be produced. Thus, the first mold component 100 carries, for example, a first mold surface 101 corresponding to the front surface profile 24a of the blade, while the second mold component 200 carries, for example, a second mold surface 201 corresponding to the rear surface profile 24b of the blade. The main mold cavity defined between the first mold surface 101 and the second mold surface 201 is configured to be filled with molten plastic material, which cools and hardens to form the structure of the main mold cavity.

[0044] The first seat portion 102 is formed in the first mold component 100 for receiving the first insertion component 103, such as Figures 11 to 12 As shown. The second seat portion 202 is formed in the second mold component 200 for receiving the second insertion component 203, as shown. Figures 11 to 12 As shown. When the first mold component 100 and the second mold component 200 are assembled together to form an injection mold, the first insert component 103 and the second insert component 203 are configured to connect with each other to define an end mold cavity 300 therebetween. The end mold cavity 300 is fluidly connected to the main mold cavity and conforms to the end portion of the blade to be produced. Thus, the first insert component 103 carries, for example, a first end mold surface 104 corresponding to the front surface profile 24a of the blade end, while the second insert component 203 carries, for example, a second end mold surface 204 corresponding to the rear surface profile 24b of the blade. The end mold cavity 300, defined between the first end mold surface 104 and the second end mold surface 204, is configured to be filled with molten plastic material together with the main mold cavity. Based on the desired length of the blade, the first insert component 103 and the second insert component 203 can be replaced with other first insert components and second insert components with end mold cavities of different sizes.

Claims

1. A blade for fan impellers for agricultural and livestock applications, characterized in that, The blade includes a plastic body (23) extending from the blade root (23a) to the blade tip (23b) in the span direction, the plastic body (23) having a concave-convex airfoil profile (24) whose shape, size and orientation vary along the span direction. The chord length of the concave-convex airfoil profile (24) increases from a first chord length value (CL1) at the blade root (23a) to a second chord length value (CL2) at the first intermediate leaf segment (23e) between the blade root (23a) and the blade tip (23b), and decreases from the second chord length value (CL2) at the first intermediate leaf segment (23e) to a third chord length value (CL3) at the blade tip (23b), wherein the third chord length value (CL3) is less than the first chord length value (CL1). The angle of attack of the concave-convex airfoil profile decreases from a first angle value (α1) at the root of the blade (23a) to a second angle value (α2) at the tip of the blade (23b).

2. The blade of claim 1, wherein The first intermediate leaf segment (23e) is positioned closer to the leaf root (23a) rather than the leaf tip (23b).

3. The blade of claim 2, wherein, The first chord length (CL1) is between 166 mm and 206 mm, the second chord length (CL2) is between 192 mm and 242 mm, and the third chord length (CL3) is between 102 mm and 141 mm.

4. The blade according to any one of claims 1 to 3, characterized in that The first angle value (α1) is between 32° and 46°, and the second angle value (α2) is between 11.5° and 15.5°.

5. A fan impeller for agricultural and livestock applications, characterized in that, The fan impeller includes an impeller hub (21) and a plurality of blades (22) extending from the impeller hub (21), wherein each of the plurality of blades includes a plastic body (23) extending in a radial direction (r) from the blade root (23a) to the blade tip (23b), the plastic body (23) having an airfoil profile (24) whose shape, size and orientation vary along the radial direction (r). The chord length of the concave-convex airfoil profile (24) increases from a first chord length value (CL1) at the blade root (23a) to a second chord length value (CL2) at the first intermediate leaf segment (23e) between the blade root (23a) and the blade tip (23b), and decreases from the second chord length value (CL2) at the first intermediate leaf segment (23e) to a third chord length value (CL3) at the blade tip (23b), wherein the third chord length value (CL3) is less than the first chord length value (CL1). The angle of attack of the concave-convex airfoil profile (24) decreases from a first angle value (α1) at the root of the blade (23a) to a second angle value (α2) at the tip of the blade (23b).

6. The fan wheel of claim 5, wherein, The first intermediate leaf segment (23e) is positioned closer to the leaf root (23a) rather than the leaf tip (23b).

7. The fan wheel of claim 6, wherein, The first chord length (CL1) is between 166 mm and 206 mm, the second chord length (CL2) is between 192 mm and 242 mm, and the third chord length (CL3) is between 102 mm and 141 mm.

8. The fan wheel of any one of claims 5 to 7, wherein, The first angle value (α1) is between 32° and 46°, and the second angle value (α2) is between 11.5° and 15.5°.

9. An injection mold for producing the blade according to claim 1, characterized in that, The injection mold includes a first mold component (100) and a second mold component (200), the first mold component and the second mold component being configured to be connected to each other to define a main mold cavity therebetween, the main mold cavity conforming to a blade to be produced, the main mold cavity being configured to be filled with molten plastic material, wherein a first seat (102) is formed in the first mold component (100) for receiving a first insert (103), and a second seat (202) is formed in the second mold component (200) for receiving a second insert (203), wherein the first insert (103) and the second insert (203) are configured to be connected to each other to define an end mold cavity (300) therebetween, the end mold cavity being fluidly connected to the main mold cavity and conforming to the end portion of the blade to be produced.

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