Axial Expansion Joint

Axial expansion joints are designed to accept movements of extension and compression in the longitudinal direction.  When the expansion joint compresses or extends, it causes the whole length to either increase or decrease.  If in a piping system, axial expansion joints are designed without restraining bars, the pipeline will require fixed points and proper anchors to overcome the reaction forces generated by the bellows.  The length of an expansion joint in a neutral position is called a free length.  In order to achieve more cycle life, axial expansion joints should be installed under pre-tense condition also known as cold pull.

Types of axial expansion joints:

  • Axial expansion joint with fix flanges


  • Axial expansion joint with free flanges


  • Axial expansion joint with pipe ends

bellows with pipe ends