Axial fans play a vital role in ventilation, cooling, and HVAC applications across various industries. As a leading manufacturer of industrial ventilation solutions in China, Zhejiang Shuangyang Fans Holding Co., Ltd provides high-efficiency axial fans engineered for metro tunnel systems, factories, commercial buildings, and more. Understanding of the structure of axial fan is essential to assess its performance, durability, and adaptability for different applications.

Core Components of an Axial Fan

An axial fan moves air along the axis of the fan shaft. The key components of its structure include:

• Fan Impeller (Blades + Hub)

• Motor

• Housing or Casing

• Inlet Cone or Bellmouth

• Mounting Frame or Support Bracket

• Protective Grilles or Louvers

• Optional: Sound Attenuators, Guide Vanes

Each component is engineered for optimal aerodynamic performance, reliability, and noise control. The integration and arrangement of these parts determine the fan’s airflow capacity and pressure generation.

Fan Impeller: Blade and Hub Design

The impeller is the heart of the axial fan, composed of blades connected to a central hub. The blade profile, material, and pitch angle significantly affect airflow performance.

Blade Types: 

Flat, airfoil, and sickle-shaped blades are commonly used. Airfoil blades offer high efficiency and low noise.

Blade Pitch: 

Fixed or adjustable pitch blades allow customization of airflow and static pressure. Adjustable pitch is ideal for large-scale applications like tunnel ventilation or high-rise building exhaust.

Materials: 

Carbon steel, aluminum, stainless steel, or reinforced plastic are selected based on corrosion resistance, strength, and weight.

Connection:

Blades are attached to the hub using riveting, welding, or bolted connections. In heavy-duty models, bolted adjustable-pitch blades are preferred for maintenance flexibility.

Motor and Drive Mechanism

Axial fans can be direct-drive or belt-drive:

Direct-drive axial fans have the motor directly connected to the impeller shaft. This ensures compact structure, low maintenance, and high efficiency, commonly used in HVAC and industrial applications.

Belt-drive designs allow speed variation and reduce vibration transmission, but they require more maintenance.

For high-performance applications, EC motors (Electronically Commutated) and variable frequency drives (VFD) are used to enhance energy efficiency and control.

Fan Housing and Casing

The fan casing not only protects internal components but also influences airflow pattern and noise levels. It can be:

Cylindrical: 

Typical for duct-mounted or inline axial fans.

Square or Rectangular with Flanges: 

Common for wall-mounted exhaust fans or unitary ventilation systems.

Acoustic Enclosures: 

Found in cabinet axial fans, which reduce operational noise using internal lining materials.

Premium casings include anti-corrosion coatings and vibration-damping structures, essential in coastal, chemical, or underground environments.

Installation Options

Axial fans are versatile in installation:

• Wall-mounted (sidewall exhaust fan)

• Ceiling-mounted

• Roof-mounted

• Duct-connected inline axial fans

• Free-standing for large-scale industrial use

Structural supports include mounting feet, anti-vibration pads, and shock mounts.

Accessories and Enhancements

These structural enhancements help axial fans meet specific noise, safety, or aerodynamic standards required by local codes.

Conclusion

The structure of an axial fan is more than a sum of its parts—it’s a carefully engineered system designed for aerodynamic efficiency, mechanical strength, and adaptability to diverse environments. Whether it’s a tunnel, metro project, industrial workshop, or HVAC system, selecting the right structure is key to achieving optimal ventilation performance and energy savings.

At SHUANGYANG FAN, we provide axial fans with customizable structures to meet the demanding technical requirements. With advanced production and testing capabilities, we deliver quality you can rely on.

Note: The content of the article cannot avoid omissions and errors. Welcome to propose corrections.