Axial fans are one of the oldest fan designs and are widely used in our lives.
This article will introduce the relevant knowledge and selection points about axial fans
If you are looking for the right axial fan to start your business, hopefully this will solve your problem.
1.What is an axial fan?
Axial fans are the oldest fan design. The early use of axial fans can be seen in man's earliest wooden windmills.
Today you can see him almost anywhere, such as the cooling fan of the computer around you.
Axial fans flow air axially or parallel to the axis to which the fan blades are attached. Axial fans are used to move heated or cooled air or for ventilation applications.
2.What are the characteristics of using an axial flow fan?
Axial fans are designed for specific operating points.
The operating point consists of the amount of air (CFM, liters/sec) produced at static pressure (in/HG, Pascals).
Axial fans are typically used to move large volumes of air, but with lower static pressure. Centrifugal fans move less air but have higher static pressure.
Fans are designed to run at a specific speed, while wingtip speeds are used using larger diameter wind turbines.
Axial fans have areas in the performance curve where they cannot operate and will stall.
Electric axial fans have been around for a long time, and the fan blades are attached to an AC motor that turns the fan. Recent changes have resulted in electric external motor rotors.
The fan blades of these fans are attached to the outside of the rotating motor housing. In both cases, due to the rotation of the fan, it can create an imbalance or wobble, which can cause the fan to fail.
Most of the fans used are balanced during manufacture by static or dynamic balancing, which allows the fan to run at maximum speed without wobbling.
3.Why are axial fans worth investing in?
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Efficient airflow
Axial fans ensure efficient airflow, which is why they are used as cooling towers and exhausts. If the airflow is not suitable, the cooling tower will not be able to dissipate heat. Due to the consistent airflow from the cooler fans (axial fans), the water system and fill material inside these fans function properly. Axial fans can generate a lot of air on a regular basis, and they also ensure even air circulation thanks to the airfoil blades.
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Shift
The speed of the axial fan can be easily changed to suit the needs of a cooling tower or exhaust fan. The fan continues to generate high airflow even when the speed is reduced. Conversely, reducing the speed has a direct effect on the airflow of the centrifugal fan.
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Durable Construction
Most industrial axial fans are made of aluminum, which makes them durable, reliable, lightweight and user-friendly at the same time. Sometimes they are also made of stainless steel, which improves their performance in harsh environments.
Axial fans from many manufacturers are equipped with spark-resistant and cast aluminum propellers to ensure their safety in high temperature applications. Their durable construction is one of the main reasons for using these fans in ships, aircraft, helicopters and hydrofoils.
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Quick maintenance
Axial fans have a simpler design than other industrial fan types. The design of these fans is simple and open. Therefore, any operational problems that arise can be easily identified and corrected. This is one of the reasons why these fans are widely used in industrial cooling and exhaust applications.
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Increase the service life of mechanical components
Compared to their earlier counterparts, these fans have a compact footprint and lightweight design, which helps increase the lifespan of the different mechanical components within. In general, axial fans have a longer service life than other industrial fans due to their high mechanical strength and optimized design.
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Quieter than most other industrial fans
Industrial axial fans produce lower mechanical noise than conventional fans. This makes it ideal for applications where noise can be a big concern.
4.What types of axial fans are there?
There are three basic types of axial fans: propeller, tubular and vane. Propeller fans are most commonly used for dilution ventilation or cooling. These fans are usually mounted on the wall or ceiling. Common examples are your car radiator fan or a freestanding room fan. The essential features of these fans include:
Can move a lot of air if there is little resistance, and
Not suitable for local exhaust ventilation as they do not provide enough suction to draw air into the system.
Axial and vane axial fans are essentially propeller fans installed in a duct. They are generally limited to "clean air" applications, such as exhaust pipes that run through the roof.
5.What conditions need to be considered when using an axial fan?
Axial fans are available in various standard designs. Here are a few requirements:
Fans can be duct mounted or wall mounted.
Ducted fans have a duct going through for seamless airflow.
Ring mounted fans allow airflow from one sufficiently large area to another; therefore, it is suitable for large spaces.
Circulation fans have rotating impellers and are typically used in ceiling fans.
Due to their working principle, axial fans provide large airflow rates at low pressure. The blades of these fans draw in air parallel to their axis and move forward in the same direction within the axis of the fan.
6.What are the applications of axial fans?
Axial fans move large volumes of air effectively and efficiently and are often used to cool small and large spaces. They can cool electronic equipment or computer rooms. They can be used for local cooling in HVAC operations, AC condensers, heat exchange units or in industrial systems. Axial fans can also operate as exhaust fans.
The motor regulates the speed of the axial fan and provides feedback on fan performance. Axial fans are used in many fields, including HVAC, ventilation, automotive and aircraft, to name a few.
7.What is the working principle of an axial fan?
Axial fans work like an airplane wing, where the pressure difference creates lift. The simplest axial fans have one-piece blades made of many different materials that connect to a motor to turn the blades. Larger axial fans have blades that are added to a hub attached to the motor shaft. The blades of an axial fan propeller are like wings, and they push the air forward, creating lift. Due to this lift, the air is pushed and pushed back. Even after the air leaves the fan, the speed of the air continues to increase.
Larger industrial axial fans attach the blades to the hub by rivets or welding, which is then mounted on the drive motor to turn the fan. The pitch of the blades can be from fixed to adjustable.
8.Factors Affecting the Flow of Axial Fans
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Axial fan speed
The rotational speed of the axial fan is determined by the number of coil turns in the motor, the operating frequency, the shape of the fan blades and the axial fan bearing.
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Axial impeller blade shape
The shape of the blades also affects the speed of the airflow to some extent. In axial fans, these blades can be tilted forward, backward or curved.
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Number of Axial Impeller Blades
The number of blades can vary from 2 to 20, and the power or motor capacity required to drive these fans depends on the number of blades, the speed and volume of the airflow, and other application requirements.
9.Are axial fans loud?
Generally speaking, in scenarios suitable for axial fans, the noise generated by axial fans is not large.
So in general, the sound of an axial fan will be smaller than that of a centrifugal fan.
Most axial fan manufacturers publish sound ratings for their products, which should be considered when selecting a fan.
10.What is the standard of axial flow fan?
The selection of centrifugal fans must pay attention to whether they meet relevant standards and certifications.
You should ask the centrifugal fan manufacturer to provide relevant certificates when you choose related products:
- AMCA
- CRAA
11.What is the difference between an AC axial fan and a DC axial fan?
The working principle of DC axial fans is based on Ampere's theorem. A conductor passes an electric current to generate a magnetic field around it. If a conductor is placed in another fixed magnetic field, an attractive or repulsive force is created, causing the object to generate kinetic energy. When the repulsive force is greater than the static friction of the cooling fan, the fan blades will start to run.
The working principle of the AC axial fan is to directly provide the AC power to work. Through a fixed AC frequency, the silicon steel sheet produces a magnetic field switch, which causes the cooling fan blades to generate kinetic energy and rotate. The higher the power frequency, the faster the magnetic field switching speed, and the higher the rotational speed of the AC axial fan.
The power consumption of a DC axial fan is much smaller than that of an AC axial fan, and the maximum speed that a DC fan can achieve is also higher than that of an AC fan.
Secondly, the fan blades of DC axial fans have magnets, while AC axial fans do not; DC axial fans have PCB boards, but AC axial fans do not; the appearance of AC and DC will be slightly different, and the general AC silicon steel sheet will A bit thicker than DC.
Generally speaking, as far as axial fans of the same brand are concerned, general DC fans are more expensive than AC fans.
12.What type of axial fan should be used in HVAC?
In HVAC systems, axial fans are used for cooling or dilution ventilation. These can be AC/DC powered.
Two types of fans are selectively used in HVAC systems.
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Tubular Axial Fan
In these fans, the fan blades are enclosed in the tube from the outer tip. This creates a consistent airflow. These fans are used for consistent cooling and even air output.
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Blade Axial Fan
These fans consist of blades/pockets between the blades. This helps direct airflow without creating swirling motion. These fans are ideal for variable flow cooling and ventilation applications.
13.How to choose the right axial fan for the job?
Choosing the right fan can be complicated and should be done by a ventilation or fan specialist. However, you can make the following observations to determine if the selected fan is suitable:
Material of Axial Fan
If the exhaust air contains a small amount of smoke and dust, a backward-inclined centrifugal or axial fan should be used.
If the exhaust air contains a small amount of dust, smoke or moisture, it is best to use a backward tilt or radial centrifugal fan.
Radial centrifugal fans are usually chosen if the particle load in the exhaust gas is high or when handling materials.
If the exhaust gas contains explosive or flammable substances, a spark-proof construction (or an explosion-proof motor if the motor is in the airflow) should be selected to comply with National Fire Protection Association standards and provincial government regulations.
If the exhaust air contains corrosive contaminants, it may be necessary to use a fan with a protective coating or made of special materials (stainless steel, fiberglass, etc.).
Airflow temperature
Fans that handle high-temperature exhaust air must be made of materials and components that are resistant to high temperatures.
Capacity and Physical Constraints
You may or may not know how much air the fan needs to move. You also may not know the amount of resistance in the exhaust system that the fan has to overcome and what the fan efficiency is. However, the following general information may be helpful:
Fan size should be determined based on performance requirements.
Air intake size and location, fan weight and ease of maintenance must also be considered. The most efficient fan size may not fit the available physical space.
On packaged fans, the motor is supplied and installed by the manufacturer (direct drive). On larger units, the motor is mounted separately and connected directly to the fan or indirectly via a belt drive.
Direct drive fans provide more compact components and ensure constant fan speed. Fan speed is limited by the available motor speed. The capacity is set during construction.
Belt drive fans provide flexibility in adjusting fan speed. The speed can be changed by changing the gear ratio. This flexibility may be important in some applications where changes in system capacity or pressure requirements need to be provided depending on modifications to the process, fume hood design, equipment location or air cleaning equipment.
It is common practice to choose a fan that can provide the desired airflow (volume and pressure) at no more than 80% of its full rated speed.
However, the motor chosen should be able to handle the horsepower required to reach that rated speed.
Safety
Safety guards are required at all hazardous points, such as entrances, exits, shafts, drives and cleaning doors. Construction shall comply with applicable safety requirements.
14.Common faults of axial fans
There are many common faults of axial fans, because axial fans have been in a high-load working environment, so there are many possible faults.
Rotor failure is a common failure of axial flow fans. The specific failures include rotor bending, running vibration, or the connection between the rotor and the impeller, etc., resulting in the rotor shaft idling and the impeller and the rotor slipping.
Blade failure, the blade is subjected to a lot of force during long-term work, so cracks and breakage accidents are prone to occur. At the same time, such failures are difficult to detect. Since the axial fan is always running at high speed, it is impossible to predict by any method. Impeller failure. Therefore, impeller breakage is the most common production accident of axial flow fans.
Damage to the fan bearing will cause the stator casing to lock the rotor, which will have a huge impact on the fixation of the stator casing, causing the axial fan to fall off as a whole. When the circuit is too large, the copper wires in the circuit can burn out the stator or rotor, causing huge damage to the motor, while the lack of grease can cause the components inside the fan to dry-grind, eventually locking up the bearings and rotor. Therefore, attention should be paid to adding grease in daily maintenance.
15.Why purchase axial fan manufacturers from China?
Axial fan manufacturers in China have the following advantages, which make your business fully guaranteed:
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high-quality workforce
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Young and ample high-skilled population
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Always keep costs down.
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Infrastructure and Geography
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Stable Supply Ability
16.How to find axial fan manufacturers from China?
Ways to find an axial fan manufacturer in China include
Google, Bing search
Most of the good manufacturers of axial fans have their own websites to advertise their products.
However, many excellent Chinese manufacturers do not pay attention to this or start late, but this does not mean that they cannot provide excellent products.
So it might be hard to find them on the first few pages, but you can check out a few pages with many good axial fan manufacturers to choose from.
Or you can add "China" to your keyword to see more Chinese manufacturers.
Purchasing agent
Many purchasing agents in China know the different manufacturers of axial fans in China.
They understand the production capacity and pricing of these manufacturers.
These are the important specifications your purchasing agent can help you with when searching for an axial fan
Sourcing agents can also save you the trouble of finding reliable manufacturers, as they usually have a ready list for you to choose from.
The main limitation of using a purchasing agent is the high cost of finding a manufacturer.
There's no way to compare what you pay here with what you might lose if you bet on finding a manufacturer.
Trade shows and trade shows.
Whenever a Chinese trade show is held in your country or China, you should expect Chinese manufacturers to showcase their products.
This allows you to interact with different manufacturers and ask them about different aspects of their manufacturing process.
The advantage of this method is that you can meet face-to-face with a specific manufacturer.
This allows you to negotiate different specifications with the manufacturer.
Common trade shows and fairs in China include: Canton Fair, etc.
Crucially, once you have an agreement with a specific manufacturer, you need to visit their premises before starting production.
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