Bellows

Features
The bellows is the thin walled flexible element that allows growth in a piping system while containing the pressure and medium flowing through it. Each bellows has a unique working pressure spring rate, and cycle life that are entirely dependent on its geometry and material.
Manufactures Associations standards.

The EJMA standard ensures that the bellows is designed and manufactured to a set of minimum requirements developed from empirical data and years of experience. All customers should insist that their bellows be manufactured in accordance with these standards The bellows has several corrugations called convolutions that allow movement in axial, lateral and angular directions.

A bellows is defined by the following terms used in the industry

• Pitch(q)
  
• Convolution height (w)
  
• Thickness (t)
  
• Number of plies(n)
  
• Bellows convoluted length(lb)
  
• Skirt length(lt)
  
• Bellows inside diameter (db)
  
• Design pressure (pi)
  

The following equations define some of the bellows geometry properties

• Mean diameter (Dm)=Db + w + tn
  
• Effective area, (Ae) = (pi x Dm²)/4