DH1S Danmuff
metal expansion joints

DH1S Danmuff
metal expansion joints

DH1S Danmuff<br/>
metal expansion joints
Item Description
1 Bellows
2 Outer casing / shroud
3 Internal liner
4 Cone section
5 Stop ring
6 Guide ring
7 Torsion protector
8 Media / line pipe

DH1S Danmuff
metal expansion joints


  • Untied metal expansion joints mainly for district heating applications.
  • External shroud with torsion protection, for district heating.
  • Can be installed in series.
  • 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 space required around the joint - compared to pipe loops.
  • Less supporting structure 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.


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 und Freigaben

Design code:
EJMA, 1,000 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. DH type expansion joints are delivered 100 % preset (extended) using shear bolts, which are activated during startup / first cycle.