January 20, 2021
What are Single Ply Metal Bellows and where are they used?
Single ply bellows are made up of a single tube (or ply) of sheet metal of a defined thickness.
Why are they better than multi-ply bellows?
- The Expansion joint offers a simple construction and lower manufacturing.
- They offer a higher pressure capacity compared to multi-ply expansion joints of a similar combined thickness
- They more stable and less susceptible to in-plane and column squirm.
- They are more resilient to corrosion due to their thicker wall.
What are the drawbacks?
- They are generally stiffer than multi-ply bellows, which means they need more axial force per unit compression.
- They have lower cycle life compared to a multi-ply bellows of similar wall thickness.
- Preventive leak detection is not possible in many cases.
- Longer convoluted lengths / taller convolutions are required compared to multi-ply bellows to provide similar movement compared to multi-ply bellows.
