Axial expansion joints

Axial expansion joints are expansion joints that absorb mainly longitudinal movements axially along a straight section of pipe.

HKS axial expansion joint with collar flanges

Advantages of axial expansion joints

  • Simple means of compensation
  • Smaller space requirements
  • No alteration of flow movement
  • Movement possible in any direction
  • No redirection of pipe work required
  • Low unit costs

Disadvantages of axial expansion joints

  • High axial forces at higher pressures
  • Strong fixed points and good axial pipe guides required
  • Small and medium movement absorption
  • For large expansion movements several axial expansion joints are required
  • On long stretches many fixed points and pipe guides are required
Axial expansion joint variants
Connection parts
  • Axial expansion joints can be manufactured with weld ends, fixed flanges or swivel flanges or combinations thereof, depending on customer requirements
Guide tubes
  • To avoid abrasion and turbulence (e.g. at high flow rates in pipe work systems), axial expansion joints can be equipped with inner guide tubes
Outer protection tube
  • To protect the metal bellows against mechanical effects from the outside, axial expansion joints can be equipped with outer protection tubes
One or two bellows
  • Axial expansion joints can be manufactures with one bellows or two bellows that are connected by a central tube (see also » Universal expansion joints)
Simplified graphic representation of a expansion joint in axial movement