A front vane structure for an exhaust fan

Abstract

A front fan blade structure for exhaust fan, it includes: a spherical fan hub, and several pieces of blades, the blade is arranged on the fan hub and the cylinder of the lower end of the fan hub, the blade is radially arranged on the fan hub, wherein the blade is gradually reduced in size from top to bottom in the vertical direction, and plays a role of air compression, the hub ratio of the blade is gradually increased from top to bottom, wherein the hub ratio of the upper end of the blade is less than 0.4, and the hub ratio of the lower end of the blade reaches 0.7 at the outlet, the beneficial effects of the utility model are that the spherical fan hub, the blade is gradually reduced in size from top to bottom in the vertical direction, plays a role of air compression, and the blade is arranged on the spherical fan hub and the cylinder of the lower end thereof, so that the front fan blade structure can generate high-efficiency mixed flow.

Description

Technical Field

[0001] This utility model relates to the field of ventilation equipment technology, specifically a front blade structure for an exhaust fan. Background Technology

[0002] In modern industrial, commercial, and civil buildings, ventilation equipment plays a crucial role, serving multiple purposes such as air circulation, ventilation, smoke extraction, and heat dissipation. Axial fans, as a widely used type of ventilation equipment, are popular due to their simple structure and large air volume. Traditional axial fan blades are typically designed to generate airflow parallel to the fan axis to achieve rapid air exchange.

[0003] However, traditional axial fan blade structures face many limitations and drawbacks in practical applications, especially in scenarios with high requirements for wind pressure and energy efficiency. Specifically, the existing technology mainly suffers from the following problems:

[0004] 1. Poor air pressure performance, limiting applications: While traditional axial fan blade structures generate a large air volume, the static pressure they can provide is often low. This means that in complex ventilation environments requiring long air supply ducts, numerous duct bends, or the presence of external static pressure (such as backdraft from outdoors), traditional axial fans struggle to overcome significant system resistance, resulting in a substantial decrease in air volume and an inability to effectively guarantee ventilation. This greatly limits their use in applications requiring high static pressure delivery, such as exhaust systems in multi-story buildings, long-distance air supply, or complex duct layouts.

[0005] 2. Unsatisfactory energy efficiency: Existing axial fan blade structures often consume relatively high energy when increasing airflow or air pressure. Under the same conditions of motor energy consumption, blade size, and mounting hole diameter, traditional axial fans can only produce relatively limited airflow and air pressure, resulting in low energy utilization efficiency, which does not conform to the current environmental protection trend of energy conservation and emission reduction and the ever-increasing demand for energy saving.

[0006] 3. Optimization Potential of Technical Solutions: The design of traditional axial fan blades, such as the number of blades, hub structure, blade shape, and tilt angle, often lacks consideration for optimizing both airflow and air pressure. This results in acceptable performance in a single aspect (such as airflow), but difficulty in achieving optimal overall performance (such as the balance between airflow and air pressure, and overall energy efficiency). For example, the traditional rear fan blade structure has limited room for performance improvement, thus requiring further refinement. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a front blade structure for exhaust fans that is more compact, more aesthetically pleasing, and can effectively provide air volume, air pressure, and energy efficiency.

[0008] The purpose of this utility model is achieved through the following means: a front fan blade structure for an exhaust fan, comprising:

[0009] A spherical fan hub; and

[0010] Several blades are arranged on a hub and a cylinder at the lower end of the hub, and the blades are arranged radially on the hub.

[0011] The blades are designed to gradually decrease in size from top to bottom in the vertical direction, thereby compressing the air.

[0012] In one embodiment, the blade-to-hub ratio gradually increases from top to bottom, wherein the hub ratio at the upper end of the blade is less than 0.4, and the hub ratio at the lower end of the blade at the outlet is 0.7.

[0013] In one embodiment: the outer edge of the blade is inclined at an angle A between 40° and 46°;

[0014] The outer edge curvature of the blade is between R52 and R47.

[0015] The inclination angle B of the inner edge of the blade is between 45° and 55°.

[0016] The inner edge curvature of the blade is between R32 and R36.

[0017] The angle of attack of the outer edge of the blade is less than 15°.

[0018] The angle of attack of the inner edge of the blade is less than 15°.

[0019] In one embodiment: the inner edge endpoint of the blade and the outer edge endpoint of the blade are connected to the central axis at an angle of 0-8°, and the inner edge endpoint is located in front of the outer edge endpoint.

[0020] In one embodiment, the air inlet end of the blade is designed with rounded corners.

[0021] In one embodiment, the blades are configured to be 9 to 11.

[0022] The beneficial effects of this utility model are: 1. Simple structure, low production cost, and improved market competitiveness.

[0023] 2. The spherical hub and the blades, whose dimensions gradually decrease from top to bottom vertically, compress the air. The blades, mounted on the spherical hub and its lower cylindrical end, enable the front fan blade structure to generate highly efficient mixed airflow. This mixed-flow characteristic cleverly combines the large air volume advantage of axial fans with the high air pressure advantage of centrifugal impellers, thus producing greater air volume and air pressure than traditional axial fan blades under the same motor energy consumption, blade size, and installation aperture conditions.

[0024] 3. By using a reasonable number of blades, an optimized blade-to-hub ratio, and carefully designed blade outer edge tilt angle, outer edge curvature, inner edge tilt angle, inner edge curvature, and blade angle of attack, the aerodynamic efficiency of the entire fan blade structure is maximized. Experimental data shows that, under the same test conditions, the energy efficiency of this invention is 13.6% higher than that of the traditional rear fan blade structure, the air volume is increased by 16.6%, and the air pressure is increased by 87.4%.

[0025] 4. The spherical hub design promotes centrifugal force in the airflow, further enhancing wind pressure. Meanwhile, the blades are mounted on the spherical hub and the lower cylinder, ensuring structural stability and airflow guidance. Attached Figure Description

[0026] Figure 1 , 2 This is a schematic diagram of the structure of this utility model.

[0027] Figure 3 In this utility model Figure 2 A cross-sectional view of the AA structure.

[0028] Figure 4 This is a schematic diagram of the fan hub structure in this utility model.

[0029] Figure 5 This is a schematic diagram of the blade structure in this utility model.

[0030] Figure 6 This is a schematic diagram showing the inclination angle A of the outer edge of the blade in this utility model.

[0031] Figure 7 This is a schematic diagram of the inner edge structure of the blade in this utility model.

[0032] Figure 8 This is a fan blade airflow tester for this utility model. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings. A front fan blade structure for an exhaust fan includes:

[0034] A spherical fan hub 1; and:

[0035] Several blades 2 are arranged on the fan hub 1 and the cylinder 3 at the lower end of the fan hub 1. The blades 2 are arranged radially on the fan hub 1.

[0036] The blade 2 has a gradually decreasing size from top to bottom in the vertical direction, which compresses the air.

[0037] In this embodiment: the spherical fan hub 1 design can guide the airflow along its arc surface when the fan is running, generating a certain centrifugal component, which provides a basis for increasing the pressure of the airflow.

[0038] Meanwhile, the blades 2 are radially arranged on the spherical hub 1 and the lower cylindrical part 3, forming unique inlet and outlet shapes. When the motor drives the fan blades to rotate, the blades 2 cut and accelerate the air.

[0039] Furthermore, the vertical dimension of blade 2 gradually decreases. This blade 2 shape causes the cross-sectional area of ​​the airflow channel to gradually shrink from top to bottom as air passes through blade 2, forcing the gas to be compressed. According to the continuity equation and Bernoulli's principle, the channel contraction causes the airflow velocity to increase, accompanied by an increase in pressure. This compression effect is one of the key mechanisms for achieving high wind pressure.

[0040] Through the synergistic effect of the above structural elements, the front fan blade structure can effectively accelerate and initially pressurize the air, laying the foundation for forming a mixed flow that takes into account both air volume and air pressure.

[0041] Unlike traditional axial fan blades that primarily focus on airflow, this invention utilizes a unique spherical hub and blade 2 compression design to pressurize the airflow from the source, laying the foundation for achieving high air pressure later. Furthermore, the combination of the spherical hub and blade 2 optimizes the airflow pattern entering the blade 2 region, reducing inlet losses.

[0042] Compared to traditional rear fan blade structures or solutions that require longer flow guide sections to achieve high pressure, the front fan blade structure of this invention, due to its own efficient pressurization capability, allows the rear cylinder length of the entire exhaust fan to be designed to be shorter.

[0043] The advantage of a short rear cylinder is that when the exhaust fan needs to be installed on the ceiling, but the existing ceiling height is short, such as when there is insufficient ceiling space, traditional long-cylinder exhaust fans cannot be installed. This invention reduces the reliance on a long rear cylinder by improving the pressurization efficiency of the front fan blades, thereby making the overall size of the fan more compact. It can be easily installed in narrow ceiling spaces, greatly expanding the product's application scenarios and market competitiveness, and improving the user experience.

[0044] In one embodiment, the ratio of the blade 2 to the hub gradually increases from top to bottom, wherein the hub ratio at the upper end of the blade 2 is less than 0.4, and the hub ratio at the lower end of the blade 2 at the outlet is 0.7.

[0045] In this embodiment, the hub ratio refers to the ratio of the hub diameter to the outer diameter of the blade 2. Specifically, the hub ratio at the upper end of blade 2 is small (less than 0.4): at the inlet end (upper end) of blade 2, a smaller hub ratio means that the area of ​​the blade 2 near the hub is relatively small. This facilitates smooth airflow and ensures a larger effective flow area, thereby obtaining a larger air volume.

[0046] Large hub ratio at the lower end of blade 2 (0.7): At the outlet end (lower end) of blade 2, the larger hub ratio, combined with the design of blade 2, promotes the airflow to accelerate further radially outward (centrifugal direction), thereby converting kinetic energy into static pressure and increasing wind pressure.

[0047] This gradually changing hub ratio design allows the airflow to be continuously compressed and accelerated inside the fan blades, and further pressurized through centrifugal force, thereby achieving an optimized balance of airflow and air pressure throughout the entire working process of the blade 2.

[0048] In this embodiment, by controlling the hub ratio at different radial positions, the present invention can ensure a large air volume at the air inlet and achieve high air pressure at the air outlet, taking into account the advantages of both axial and centrifugal fans, and is one of the key designs to achieve the mixed flow effect.

[0049] At the same time, it effectively converts and enhances the kinetic and static pressure energy of the airflow, improving the aerodynamic efficiency of the entire fan blade structure. This allows the fan blade to maintain high performance under different operating conditions, especially better adapting to scenarios that require balancing airflow and air pressure.

[0050] In one embodiment: the inclination angle A of the outer edge 21 of the blade 2 is between 40-46°, preferably 43.55°, ±1.5°;

[0051] The outer edge curvature of the blade 2 is between R52 and R47, preferably R49, ±2;

[0052] The inclination angle B of the inner edge of the blade 2 is between 45-55°, preferably 51.46°, ±2.5°;

[0053] The inner edge curvature of the blade 2 is between R32 and R36, preferably R34, ±2.

[0054] In this embodiment:

[0055] The outer edge tilt angle A and the inner edge tilt angle B determine the effective area of ​​air cutting by blade 2 and the direction of airflow guidance. A reasonable tilt angle can maximize the working efficiency of blade 2, ensure that the airflow flows smoothly along the surface of blade 2, and reduce energy loss.

[0056] Among them, the curvature of the outer edge line: The curvature (radius) of blade 2 directly affects the speed and pressure changes of airflow passing through blade 2. By precisely controlling the curvature of the outer edge line and the inner edge line 22, the pressure difference distribution on the surface of blade 2 can be optimized, thereby generating greater lift and more effective pressure boost.

[0057] The limits of these parameters were obtained through extensive experiments and optimizations, ensuring that when the blade 2 rotates, it can effectively cut the air to generate airflow and also achieve pressurization by guiding and accelerating the airflow, while avoiding airflow self-interference and the generation of eddies.

[0058] In this embodiment, the precise tilt angles A and B, as well as the arc design, ensure that blade 2 operates with optimal efficiency, increasing the effective shear area and thus effectively improving airflow and air pressure. Furthermore, it avoids the airflow self-interference problem between blades 2 that may occur in traditional designs, preventing airflow from decreasing instead of increasing, and effectively improving energy efficiency.

[0059] In addition, the optimized blade geometry helps to achieve a smoother airflow, reduce the generation of turbulence and eddies, and thus reduce the noise of the fan during operation to some extent.

[0060] In one embodiment, the angle of attack of the outer edge of the blade 2 is less than 15°, preferably 12°, ±1.5°.

[0061] In this embodiment, the angle of attack refers to the angle between the chord line of blade 2 and the direction of incoming flow. According to Bernoulli's principle and airfoil theory, within a certain range, the larger the angle of attack, the greater the lift generated by blade 2 (corresponding to wind pressure and airflow). However, an excessively large angle of attack (exceeding the critical angle of attack) will cause the airflow to separate from the surface of blade 2, resulting in stall, which in turn causes a sharp decrease in lift and a sharp increase in drag. Limiting the angle of attack of the outer edge of blade 2 to less than 15° ensures that the outer edge of blade 2 is always in the high-efficiency lift zone during operation, avoiding stall.

[0062] In this embodiment: the outer edge of blade 2 is always kept in optimal aerodynamic condition to maximize lift generation, thereby effectively increasing airflow and air pressure. Simultaneously, it avoids increased resistance caused by airflow separation, improving fan operating efficiency. Furthermore, it avoids performance fluctuations caused by blade 2 stall, ensuring stable fan operation.

[0063] In one embodiment, the angle of attack of the inner edge of the blade 2 is less than 15°, preferably 4°, ±1.5°.

[0064] In this embodiment, the inner edge of blade 2 is close to the hub and is mainly responsible for pressurizing and guiding the airflow. The angle of attack of the inner edge is also limited to less than 15°, especially considering that the airflow velocity in this area is relatively low but the pressure change is significant. This ensures that the inner edge can efficiently pressurize while avoiding airflow separation and vortices, and ensures that the airflow is smoothly guided radially outward.

[0065] In one embodiment: the inner edge endpoint of the blade 2 and the outer edge endpoint of the blade 2 are connected to the central axis at an angle of 0-8°, and the inner edge endpoint is located in front of the outer edge endpoint.

[0066] In this embodiment, there is an angle between the endpoints of the inner and outer edges of blade 2 and the line connecting it to the central axis 4, which causes blade 2 to have a certain tilt in both the axial and radial planes. This design guides the airflow to acquire a radial (centrifugal) component in addition to the axial motion when passing through blade 2.

[0067] The inner edge endpoint is located in front of the outer edge endpoint: This relative position further strengthens the radial movement tendency of the airflow, causing the airflow to form a spiral flow inside the blade 2, thereby effectively converting energy into static pressure and enhancing wind pressure.

[0068] In one embodiment, the air inlet end of the blade 2 is designed with rounded corners. The air inlet end of the blade 2 is the first contact point where the airflow enters the working area of ​​the blade 2. Designing the air inlet end with rounded corners allows for a smoother and more continuous transition of the airflow as it enters the surface of the blade 2. This helps to prevent airflow separation, the generation of eddies and turbulence at sharp edges, thereby reducing flow resistance. At the same time, the smooth air inlet end effectively reduces the impact and frictional resistance of the airflow, reducing the energy consumption during fan operation. In addition, reduced airflow separation means more effective airflow guidance, thereby increasing the lift generated by the blade 2 and helping to increase the air volume.

[0069] In one embodiment, the blade 2 is configured to have 9 to 11 blades.

[0070] In this embodiment: the number of blades 2 is large (compared to traditional axial flow fans): within a certain range, increasing the number of blades 2 can increase the frequency and contact area of ​​the interaction between the blades 2 and the air, thereby improving the energy transfer efficiency of the airflow and helping to generate greater wind pressure and more stable airflow.

[0071] The 9-11 blade design, a range proven through testing, achieves an optimized balance of airflow, air pressure, and energy efficiency within this blade structure. Too few blades may result in insufficient air pressure, while too many blades may exacerbate airflow interference between blades, increase drag, and raise noise levels, ultimately reducing efficiency.

[0072] Therefore, this design ensures that the number of blades 2 provides sufficient energy transfer surface to effectively increase airflow pressure. At the same time, while maintaining high wind pressure, it avoids airflow interference and noise problems caused by an excessive number of blades 2, achieving a performance balance.

[0073] In summary, the core working principle of the front fan blade structure of the present invention lies in the efficient integration of the advantages of axial flow and centrifugal fans through a unique multi-element collaborative design, generating a mixed airflow that balances large air volume and high air pressure.

[0074] Based on the applicant's testing:

[0075] 1. The maximum airflow of the traditional rear fan blade structure is 78.35 m³ / min, power is 8.9W, maximum pressure is 26.39Pa, and energy efficiency is 0.147 m³ / min*W.

[0076] 2. The maximum air volume of this structure is 91.32 m³ / min, the power is 9.12 W, the maximum pressure is 49.45 Pa, and the energy efficiency ratio is 0.167 m³ / min*W.

[0077] All the above data were obtained using the same testing equipment and under the same testing conditions. (National standard for energy efficiency of ventilation fans: Type A, Level 1: 0.13 m³ / min*W (shaded pole); Type B, Level 1: 0.08 m³ / min*W, GB32049-2015)

[0078] Comparing the above data, under the same motor parameters, the SN and SM front fan blade structure increases air volume by 16.6%, air pressure by 87.4%, and energy efficiency by 13.6% compared to the traditional rear fan blade structure.

[0079] Specifically, its working principle is mainly reflected in the following aspects:

[0080] High-efficiency pressurization and centrifugal action:

[0081] The spherical fan hub 1 generates a centrifugal component while guiding the airflow.

[0082] The vertical dimension of blade 2 gradually decreases, which increases the airflow speed and pressure by compressing the airflow.

[0083] The precise tilt angles A and B, as well as the radian, of the inner and outer edges of blade 2, along with the angle of attack and a design of less than 15°, ensure that blade 2 efficiently cuts through the air and generates maximum lift while minimizing drag.

[0084] The angle design (0-8°) between the inner and outer edge endpoints of blade 2 and the central axis 4 further enhances the centrifugal effect and pressure boost of the airflow by guiding the airflow to generate a clear radial component.

[0085] These structures work together to effectively increase the speed of airflow as it passes through the fan blades, and also significantly increase its static pressure, thereby overcoming the high system resistance that traditional axial fans struggle to handle.

[0086] In addition, the gradually changing hub ratio (<0.4 at the top to 0.7 at the outlet) optimizes the airflow acquisition at the inlet and the air pressure conversion at the outlet, ensuring efficient energy conversion throughout the airflow path.

[0087] The optimization of the number of blades 2 from 9 to 11 ensures that blades 2 interact with the air at a sufficient frequency, effectively transferring energy.

[0088] The rounded corner design at the air inlet minimizes airflow resistance loss, ensuring smooth airflow and improving air volume and energy efficiency.

[0089] These ingenious structural designs enable the front fan blades to achieve highly efficient energy conversion within a limited space, generating significantly higher air pressure and greater air volume than traditional axial fans. This highly efficient mixed-flow pressurization characteristic allows for a shorter rear cylinder structure to achieve the same or even better ventilation effect, thus solving the problem of installing exhaust fans in low-ceilinged spaces. At the same time, it achieves energy conservation and emission reduction while ensuring air volume, air pressure, and reducing noise.

[0090] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A front blade structure for an exhaust fan, characterized in that, include: A spherical fan hub (1); as well as Several blades (2) are arranged on the fan hub (1) and the cylinder (3) at the lower end of the fan hub (1). The blades (2) are arranged radially on the fan hub (1). The blade (2) has a gradually decreasing size from top to bottom in the vertical direction, which compresses the air.

2. The front blade structure for an exhaust fan according to claim 1, characterized in that: The ratio of the blade (2) to the hub gradually increases from top to bottom, wherein the hub ratio at the upper end of the blade is less than 0.4, and the hub ratio at the lower end of the blade at the outlet is 0.

7.

3. A front blade structure for an exhaust fan according to any one of claims 1 to 2, characterized in that: The inclination angle A of the outer edge (21) of the blade (2) is between 40-46°; The outer edge (21) of the blade (2) has an arc between R52 and R47; The inclination angle B of the inner edge line (22) of the blade (2) is between 45° and 55°. The inner edge (22) of the blade (2) has an arc between R32 and R36.

4. The front blade structure for an exhaust fan according to claim 3, characterized in that, The angle of attack of the outer edge of the blade (2) is less than 15°.

5. The front fan blade structure for an exhaust fan according to claim 3, characterized in that, The angle of attack of the inner edge of the blade (2) is less than 15°.

6. The front blade structure for an exhaust fan according to claim 1, characterized in that: The inner edge endpoint of the blade (2) and the outer edge endpoint of the blade are connected to the central axis (4) at an angle of 0-8°, and the inner edge endpoint is located in front of the outer edge endpoint.

7. The front blade structure for an exhaust fan according to claim 1, characterized in that: The air inlet end of the blade (2) is designed with rounded corners.

8. The front blade structure for an exhaust fan according to claim 1, characterized in that: The blades (2) are set to 9 to 11.

Images