DX3S DanOne
metal expansion joints

DX3S DanOne
metal expansion joints

DX3S DanOne<br/>
metal expansion joints
Item Description
1 Media/ line pipe
2 Bellows
3 Outer casing / shroud
4 Inner casing / shroud

DX3S DanOne
metal expansion joints


  • Untied metal expansion joints mainly for district heating.
  • External sealable shroud.
  • Can be installed in series.
  • One cycle / startup type expansion joint, for ease of installation.
  • Designed for large axial movements.


  • No significant pressure drop - reduced need for pumps and general power consumption for moving media, compared to pipe loops.
  • Less supporting structure or excavation required – Compared to pipe loops.
  • Lower erosion rate (for abrasive media lines – compared to pipe loops with elbows).
  • Multiply bellows with low spring rate and high cycle life.

Operating range

Diameter: DN 40 ... DN 600 (1.75" ... 24”)
Temperature: ... 120 °C (248 °F)
Pressure: 16 barg (232 PSIG), 25 barg (362 PSIG)


  • Bellows: 1.4541 (AISI 321)
  • Connections: 1.0345 – (P235GH)

Other materials are available on request.

Standards and approvals

Design code:
EJMA, (4-5) Cycles

NDT and documentation:
Can be provided per customer request e.g.,
material certificates and NDT test reports.


Custom designs and sizes are available on request. Untied metal expansion joints require guide and support. DX3S type expansion joints are used to ease installation by facilitating movement during the first startup. Once in operation, the expansion joint is fix (seal) welded.