Special Products · Witzenmann
Flexible Joints
Witzenmann HYDRA® metal expansion joints — multi-ply stainless steel bellows that absorb thermal expansion, vibration and misalignment in piping. Axial, lateral, angular and universal designs from Witzenmann, Pforzheim, Germany.
HYDRA® expansion joints · standard and custom designs
By movement
Which expansion joint for your pipe?
Choose by the movement the joint has to absorb. Not sure? Send us the pipe data and our engineers will select the type.
Axial
Movement along the pipe axis.
- Axial movement up to approx. 200 mm
- Small lateral and angular movement
- Unrestrained: the pipe anchors carry the pressure thrust
Lateral
Movement across the pipe axis.
- One plane with hinge bracing
- All planes with gimbal bracing
- Bracing carries the pressure thrust (no axial movement)
Angular
Angular movement, usually 2 or 3 joints working as a hinge system.
- One plane with hinge bracing
- All directions with tie rod or gimbal bracing
- Bracing carries the pressure thrust
Universal
Two bellows joined by a centre pipe.
- Axial, lateral and angular movement in one unit
- Unrestrained: the pipe anchors carry the pressure thrust
- Low-pressure versions for exhaust gas
Product range · 01
Axial expansion joints
Multi-ply stainless steel bellows in three movement ranges per pressure stage and nominal diameter. Also available as low-pressure versions.
Type ABN
Axial expansion joint with swivel flanges — bolt holes align freely during installation.
Movement: axial · Ends: swivel flanges
Type AFN
Axial expansion joint with smooth fixed flanges.
Movement: axial · Ends: fixed flanges
Type ARN
Axial expansion joint with welding ends for welded pipelines.
Movement: axial · Ends: welding ends
Product range · 02
Special axial expansion joints
For apparatus construction, corrosive media and lines where the pressure thrust must not reach the anchors.
Type AON
Single-ply expansion joint for apparatus construction.
Movement: axial · Single-ply bellows
Type ABT
Axial expansion joint with PTFE lining for corrosive media.
Movement: axial · PTFE-lined
Type ARH
Axial expansion joint with an automatic release mechanism.
Movement: axial · Automatic release
Type DRD
Pressure-balanced axial expansion joint: no pressure thrust on the anchors.
Movement: axial · Pressure-balanced
Product range · 03
Lateral expansion joints
Absorb movement across the pipe axis. The bracing carries the pressure thrust.
Type LBR
Lateral expansion joint with swivel flanges, for movement in all planes.
Movement: lateral, all planes · Ends: swivel flanges
Type LFR
Lateral expansion joint with smooth fixed flanges, movable in all directions.
Movement: lateral, all planes · Ends: fixed flanges
Type LRR
Lateral expansion joint with swivel flange, for movement in all planes.
Movement: lateral, all planes · Ends: swivel flange
Type LRK / LRN
Lateral expansion joint with welding ends.
Movement: lateral · Ends: welding ends
Type LBS
Noise-insulated lateral expansion joint with swivel flanges.
DN 50–2000 · Ends: swivel flanges
Product range · 04
Angular expansion joints
Single-plane (hinge) or all-direction (gimbal) designs, usually installed in sets of two or three.
Type WBN / WBK
Angular expansion joint with swivel flanges.
Movement: angular · Ends: swivel flanges
Type WFN / WFK
Angular expansion joint with plain fixed flanges.
Movement: angular · Ends: fixed flanges
Type WRN / WRK
Angular expansion joint with welding ends.
Movement: angular · Ends: welding ends
Product range · 05
Universal expansion joints
Two bellows and a centre pipe absorb axial, lateral and angular movement. Also available for low pressure (exhaust gas).
Type UBN
Universal expansion joint with swivel flanges.
Movement: axial, lateral, angular · Ends: swivel flanges
Type UFN
Universal expansion joint with plain fixed flanges.
Movement: axial, lateral, angular · Ends: fixed flanges
Type URN
Universal expansion joint with welding ends.
Movement: axial, lateral, angular · Ends: welding ends
Product range · 06
Building services (HVAC)
Standard expansion joints for steel, stainless steel and copper pipes in water, heating and gas installations — DN 15 to DN 250.
Axial expansion joints
Axial expansion joints with screw connections, threaded ends, flanges or welding ends.
DN 15–250 · water, heating, gas
Sound insulation expansion joints
Sound-insulating expansion joints for building services piping.
Building services
Downloads (PDF, Witzenmann): Product overview HYDRA® expansion joints · Expansion joints manual · Operating and installation instructions · Enquiry form for expansion joints
Product images and data: Witzenmann GmbH, Pforzheim · witzenmann.com
Talk to an engineer
Send us your pipe data
Nominal diameter, pressure, temperature, medium and the movements to absorb — we select the right HYDRA® type and quote from Bangkok.