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.