Expansion Joints

Expansion joints are flexible pipe elements that absorb thermal expansion and other movement. They comprise an elastic bellows with a connecting element such as a flange.

An expansion joint reduces loads caused by expansion, mechanical vibration, acoustic vibration and stress. It may also reduce noise, accommodate installation inaccuracies within tolerances and seal pipe penetrations through walls.

Expansion joints are used in pipelines and at pumps, valves and equipment. Named fields include construction, plant engineering, water and wastewater, engine building, shipbuilding, and solar and wind power installations.

Define the movements and directions that must be accommodated. Then check nominal diameter, bellows material, flange connection, standard, pressure and temperature. Available installation length and correct fitting must also be considered.

Key attributes include elastic bellows, rotating flanges, multiple elastomer grades and, depending on type, DIN PN 10 and conformity with standards such as TÜV/DIN 4809.

Frequently asked questions

Expansion joints absorb thermal expansion, mechanical and acoustic vibration, and stress in pipework. Permitted displacement depends on the selected type and direction of movement.

They are fitted in pipelines and at pumps, valves and equipment. Available space, pipe alignment and the flange interface help determine the installation position.

An expansion joint may combine an elastic bellows with rotating flanges. For type 50, electro-galvanised steel flanges drilled to DIN PN 10 are stated as standard.

Bellows form and available installation length affect the expansion that can be accommodated. Select the version in relation to both movement and space in the pipeline.