Air Bellow Working Principle And Failure Prevention

The Working Principle of the Air Bellow

An air bellow is a device that uses compressed gas in a sealed container to perform spring-like functions by exploiting the gas compressibility. Therefore, the air bellow can automatically adjust its stiffness in response to changes in load, thus exhibiting ideal operating characteristics.

When an air bellow is in operation, it is filled with compressed air, forming a column of compressed air that provides support.

When the external vibration load increases, the air bellow is compressed, the spring bellow height decreases, and the internal cavity volume decreases.

At the same time, the compression of air increases the stiffness of the air bellow, increases the effective bearing area of ​​the air column inside the cavity, and enables the spring to withstand greater loads.

When the vibration load on the air bellow decreases, the height of the spring bellow gradually recovers, and the internal cavity area increases.

As the supporting effect of the compressed air inside the air bellow weakens, the stiffness of the bellow also decreases, and its load-bearing capacity diminishes.

Because the air bellow can adaptively adjust its stiffness and load-bearing capacity according to changes in vibration load within its effective stroke range, it always maintains good support performance.

Therefore, the air bellow is widely used in applications such as equipment vibration reduction, buffering, and improving operational stability.

Proper Installation to Prevent Air Bellow Failures

In actual industrial production, the working environment is far more complex than imagined.

Therefore, for the application of the air bellow, it is necessary to design a limiting device at the highest and lowest positions of its stroke to reserve a certain distance space.

Minimum Height Limit of the Air Bellow

The minimum height of the air bellow under compressed conditions is usually designed to be slightly higher than the height of the spring bellow when it is fully compressed.

This is because prolonged compression of the air spring bellow causes continuous stress on the rubber material, which may result in fatigue damage and accelerate the premature failure of the air bellow.

Therefore, a lower limit device needs to be set during the design process to prevent the air bellow from exceeding the minimum allowable compression height.

Usually, there are two ways to set the lower limit of the air bellow.

One approach is to set an external lower limit.

For example, steel limit blocks can be placed around the air bellow, with their limiting height slightly higher than the minimum height of the air bellow, to limit its further compression.

Another method is to install an internal cushioning pad inside the air bellow.

So the compression stroke of the air bellow is limited by the internal structure to prevent the spring bellow from being over-compressed.

Maximum Extension Limit of the Air Bellow

During the use of the air bellow, when they approach their maximum extension distance, a length limit device should also be installed to prevent the spring bellow from being damaged due to overextension.

This is because the air bellow is typically composed of metal parts and a rubber air bladder.

If the air bellow is stretched beyond the maximum allowable elongation of the airbag, it will cause a series of problems.

First, the air bellow itself has limited tensile strength. Long-term exposure to excessive tensile force will cause fatigue of the rubber material, accelerate the aging of the bellow, and thus seriously affect the service life of the air bellow.

Secondly, the air bellows are typically connected to the end caps using a rolled-edge design.

When the air bellow is subjected to excessive tensile force, stress concentration is likely to occur in the connection area, causing the rubber bellow to tear at the connection with the end cap, ultimately leading to the failure of the air bellow.