Design and Application for Multi-Ply Bellows

Multi-Ply bellows has been used widely due to the consideration of safety and the efficiency of reducing thrust.

Comparing with single ply bellow, Multi-Ply bellows has the advantages of small rigidity, large compensation quantity and good security. Although multiple bellows has many merits, decide to choose it or not should be based on the specific working condition and production costs.

When the total thickness of Multi-Ply bellows is same as single ply one, the advantage of using Multi-Ply bellows is that its fatigue life would be longer, the rigidity and elastic reaction would be reduced. However, it is also subject to the shortcomings like declining bearing capacity, reducing pillar stability and plane stability, complicated manufacturing techniques and higher manufacturing costs.

By considering the corrosion factors, different materials are required to make up the inner layer and outer one of the bellows to adapt the different environments of the pipeline. High-end materials can be used in the inner layer as to avoid occurring of corrosion, while other layers can use some materials with lower costs. It can reduce the production costs by such compensator with anti-corrosion inner layer and high-rigidity outer layer.

It is capable to monitor if compensation is leaking or not in the annular space between layers. Discovering the damage of the inner layer in time helps to avoid the sudden stop of the system and economic loss.

Multi-Ply bellows are mostly used in: 1. Pipeline that with corrosion media, such as gas duct, hot air duct and flue gas duct in metallurgy industry; 2. Situation that requires reducing the rigidity and elastic reaction of the bellows, like overhead pipeline. 3. Situation that requires improving design margins.