How Maintaining Concentricity Ensures Performance in Low-Pressure Fan Manufacturing

Many low-pressure fan manufacturers face serious problems due to insufficient fan housing roundness: uneven impeller clearance, unstable airflow, increased vibration, loud noise, low efficiency, and poor stability.

What Happens When Concentricity Is Lost in a Low-Pressure Fan?

Uneven Impeller Clearance

If the center of the impeller and the housing of the axial low-pressure fan are not on the same central axis, after the impeller is installed, the clearance on one side will be very small, and the clearance on the other side will be very large.

In severe cases, the impeller will rub against the inner wall of the fan, resulting in equipment damage.

Increased Vibration and Noise

Uneven clearance directly leads to severe instability when the impeller rotates, causing vibration.

Vibration will further shorten bearing life and increase noise.

Reduced Airflow Efficiency

Uneven clearance results in uneven airflow distribution through the axial low-pressure fan, with excessive air volume in some areas and insufficient in others, eventually leading to low fan efficiency.

So, how to ensure concentricity?

Where Concentricity Errors Begin in Low-Pressure Fan Manufacturing

As mentioned earlier, concentricity depends on whether the centers of the housing and impeller of the axial low-pressure fan are on the same axis.

Therefore, the roundness of the housing is critical, and the accuracy during assembly is equally important.

Housing Rolling Accuracy

High precision is required for the housing rolling process. If the housing is not perfectly round after rolling, the impeller will still be off-center, no matter how carefully you assemble it. This is the foundation of ensuring fan quality.

Welding Deformation

How Manufacturing Errors Affect Low-Pressure Fan Performance

• Unstable airflow
• Increased airflow turbulence
• Higher mechanical vibration
• Lower overall fan efficiency

How Altron’s Machines Maintain Concentricity in a Low-Pressure Fan

To maintain concentricity in fan manufacturing, the primary requirement is to achieve high roundness accuracy during the casing rolling process. The four-roll bending machine can precisely control the rolling pressure, ensuring consistent roundness after the casing is formed.

Compared with traditional three-roll bending machines and manual rolling, the four-roll system reduces alignment errors and improves repeatability in mass production. Furthermore, four-roll bending machines do not leave straight ends like three-roll machines do.

This precision rolling equipment is widely used in low-pressure fan production lines, where consistent housing geometry is critical.

 

After forming, maintaining accuracy during the welding process is equally important.

 

Automated welding systems help control heat input, welding speed, and torch position, thereby reducing thermal deformation and ensuring structural consistency.

Compared with manual welding, automated systems offer higher repeatability, which is critical for preserving the roundness and concentricity of the casing.

The Altron straight seam welding machine can be equipped with an oscillator to realize small-range welding torch oscillation, suitable for different materials, with adjustable height. The main machine adopts PLC control, stable and reliable in operation, supporting both continuous full welding and segmented welding.

 

Altron also provides a complete rolling and welding production line to solve your shell manufacturing problems in one stop.

When Low-Pressure Fan Manufacturers Should Upgrade Their Production Process

With the increasing requirements for product performance and quality, traditional manual rolling & welding or semi-automatic manual production can no longer meet modern production needs, which has become the biggest bottleneck restricting the improvement of enterprise capacity and product quality.

When Production Quality Is Inconsistent

Manufacturers’ biggest fear is: Customers get a good product the first time, but receive defective ones when reordering. This huge gap directly leads to customer complaints. As complaints increase, brand reputation suffers, old customers are lost, and potential clients turn to other suppliers.

Coupled With Frequent Repairs

If you often need to adjust a part to achieve basic functions, it means that sufficient precision was lacking in the previous processes.

Rising labor costs and a shortage of experienced workers

Manual welding, forming, and calibration processes require skilled operators, making production both labor-intensive and difficult to scale.

FAQ: Low-Pressure Fan

Q: What is a low-pressure axial fan?

A: Low-pressure axial fans are designed to deliver large volumes of air at relatively low pressures. In these fans, air flows parallel to the fan axis, similar to how air flows through a propeller. They are commonly used in applications requiring high airflow with low system resistance, such as building ventilation, cooling systems, and industrial exhaust.

Q: What is the typical pressure range for low-pressure axial fans?

A: Low-pressure axial fans typically operate at pressures below 1000 Pa.

Q: What are the advantages of low-pressure axial fans?

• High airflow capacity
• Simple structure
• Lower energy consumption in low-resistance systems
• Compact installation

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