DH1S Danmuff
metal expansion joints

DH1S Danmuff<br/>
metal expansion joints For a larger view, please mouseover the image.
For a larger view, please mouseover the image.
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
  • 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.
Design code:
EJMA, 1,000 Cycles

NDT and documentation:
Can be provided per customer request e.g.,
material certificates and NDT test reports.
  • Power plant technology
  • Building services industry
  • District heating & cooling
  • Water cooling systems
  • Air and steam transport lines
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.