Pipe expansion bellows, otherwise known as pipe expansion joints or pipe compensators are used in piping where the movement in the pipe exceeds the natural flexibility of the piping. Pipe expansion bellows increase the flexibility in the piping to reduce loads on the system and connected equipment to safe levels.
When a pipeline is subject to a change in temperature it will expand or contract in direct proportion to that change. Expansion joints are primarily designed to compensate for thermal expansion but it is not the only movement being imposed on the pipeline system.
Other types of movements can occur that need to be taken into account when providing a pipework flexibility solution such as building settlement, wind loading, vibration from rotating and reciprocating machinery.