Axial fans play a decisive role in ventilation systems when it comes to transporting air or process gases over long distances (axially). Compared to centrifugal fans, they are characterized by a high air flow rate combined with a low pressure increase. These fans are primarily used in areas where a continuous air flow is essential – including in air conditioning systems, cooling and heating systems and in various industrial processes.
Axial fan definition
An axial fan is the most widely used type of fan in ventilation technology. Its primary task is to transport air in order to exchange heat or cold. In contrast to other fans, the axis of rotation of the axial impeller is aligned with the direction of the air flow, which results in a high air flow rate at low pressure. Axial fans are present in a variety of environments, including offices, public facilities, industrial halls and processes and private residential areas, where they are used to move large volumes of air at low pressure.
Advantages of axial fans
- Compact design: Ideal for confined installation situations.
- Direct intake and discharge: Enables efficient air routing.
- Simple design: Reduces complexity and susceptibility to errors.
- Cost-efficient development and production: Reduces production costs.
- High efficiency: Ensures optimum energy utilization.
- Flexible controllability: Customizable through various regulation techniques.
- Wide range of applications: Can be used in numerous industries and applications.
- Long service life: Depends on the quality of the bearing selected.
Functionality of axial fans
Axial fans convey air by means of a rotating impeller that is aligned along its axis of rotation, which generates an axial air flow. This type of movement is comparable to the way airplane propellers or ship propellers work. As soon as the fan is activated, the impeller rotates and draws in air, which is then transported along the axis of rotation in the desired direction – forwards or backwards.
The rotation of the impeller creates a vacuum that draws in air and guides it through the fan. The speed and volume of this air flow is controlled by a speed controller that adjusts the fan’s rotational speed.
Axial fans are primarily used where high air volumes with low resistance are required. They are available in different configurations, for example as models without a housing or as versions with a stainless steel housing and internal drive motor. Whether they are wall fans, axial tube fans or other axial fans, models with a housing can have problems with hub dead water collecting behind the hub of the impeller. However, this challenge can be largely avoided by using a suitable diffuser, such as an internal diffuser.
Features of axial fans
Axial fans are characterized by their compact design and straight air flow, which makes them ideal for direct intake and discharge, for example in wall or window fans. Their simple design enables cost-effective development and production. Due to their steep characteristic curve, it is important to calculate the system pressure accurately when they are used in ventilation systems. Although high speeds can increase the available pressure and air volume, they also contribute significantly to noise generation.
Axial fans can be controlled by various methods, including throttling, adjusting the blades of the impeller or speed control on variable speed motors. The versatility, high performance and ease of control make them a popular choice in various applications.
Axial fan Areas of application
Axial fans are used in a variety of areas, including offices, industrial halls and processes, public spaces and private households, especially when it comes to moving large volumes of air at low pressure. Their flexible dimensions make them suitable for various applications, such as in cooling systems, water cooling of computer systems and compact cooling systems. Due to their large capacity, axial fans are also ideal for ventilating large spaces such as factory halls and workshops.
They are also frequently used in the agricultural sector, for example in pigsties, where special forward-curved blades are used to transport extra large volumes of air.
Comparison of axial and centrifugal fans
Axial fans draw in the ambient air parallel to the axis of rotation at an angle of 180° and discharge it in the same direction. They generate only a small increase in pressure, which makes them ideal for applications that require a high air flow rate with low resistance, such as room ventilation. Their flexible size facilitates installation. In contrast, centrifugal fans draw in air along their motor axis and blow it out at a 90° angle. This results in a higher pressure increase, which makes them particularly suitable for applications that have to overcome high resistance, such as flow through filters. Despite their larger footprint, they often offer more efficient performance and operate more quietly.
Differences between axial and centrifugal fans at a glance
Axial fans:
- Suck in air at a 180° angle parallel to the axis of rotation and expel it
- Lower pressure increase, suitable for high air flow rates with low resistance
- Easy installation thanks to flexible dimensions
Centrifugal fans:
- Draw in air via the motor shaft and blow it out at a 90 degree angle
- Higher pressure increase, ideal for applications with high resistances
- Better efficiency and lower noise level despite larger space requirements
Important decision factors:
- System requirements
- Advantages and disadvantages of the designs
- Specific applications
Serafima: Your expert for axial fans
If you are considering the installation, overhaul, modification, optimization or maintenance of an axial or centrifugal fan – either at your site or in our factory – or need spare parts for your process plant, Serafima is your ideal partner. With over 70 years of experience, we supply customized solutions for fans and compressors worldwide. Our experienced sales team will support you in the selection, procurement, installation and maintenance of your machines and industrial fans. Rely on Serafima as your trusted expert for expertise, quality and excellent service. Contact us today and help your company achieve the success it deserves!
Frequently asked questions (FAQ)
What characterizes an axial fan?
An axial fan is technically designed in such a way that it moves the air parallel to the axis of rotation of its impeller. It is often used for large air volume flows at low pressure. In addition, axial fans are often space-saving due to their design and can be used in various applications, including air conditioning systems, ventilation systems in buildings, cooling and heating applications and industrial processes.
What are the advantages and disadvantages of radial and axial fans in comparison?
Centrifugal fans generate higher pressure increases and are more efficient at overcoming resistance. Axial fans, on the other hand, offer more flexible dimensions and are less expensive to develop and produce. Centrifugal fans are ideal for applications where high static pressure is required, such as HVAC systems, air filters and industrial processes.
In contrast, axial fans are characterized by their ease of installation and maintenance and are therefore often the preferred choice for ventilation systems in residential buildings, offices and other environments where large volumes of air need to be moved with low pressure requirements.
What areas of application do axial fans cover?
Axial fans are used in offices, public spaces, private households