What are the various Expansion Joint add-ons?

An expansion joint can accommodate any axial, longitudinal, or angular movement in a pipeline, duct, or vessel. The addition of accessories to an expansion joint increases both the complexity and the capabilities of the joint. Expansion joint accessories include the following.



Liners or baffles are stainless steel sleeves that are fixed or flexible and are placed inside the bellows to extend the life of metallic expansion joints. Liners protect the convolutions from chemical and electrochemical erosion caused by flowing media. Because of the curved shaped convolution inner side of the bellows, turbulent flow of media occurs rather than laminar flow, which may cause an increase in pressure nearer to the expansion joint. High velocity flowing media also causes resonant vibration in bellows, which is why liners are recommended to provide smooth and laminar flow while reducing vibrations.


Where the pipe systems carry catalyst, abrasive, and other high temperature media, high gauge sleeves are required, as are high gauge sleeves for reverse flow of media.

Internal sleeves should not be used when transmitting high viscosity fluids such as heavy oil, tars, and so on, because these fluids cause packing and cooking, which leads to premature expansion joint failure. Internal liners are typically welded into the flanges of expansion joints.




The expansion joints are provided with beveled pipes for welding to compatible equipment or pipes.




The expansion joints' ends are fitted with flanges for bolting with the corresponding flanges of piping systems. Flanges are available in a variety of shapes, including squared, rounded, etc.




A ring formed of metal tube or metal strip that is used to weld flanges and is positioned in the end of bellows. Collars render the end of the bellows rigid, which may prevent the root from splitting.




Component with a "T"-shaped cross section that is attached to the roots of the convolution of bellows in expansion joints. The major role is to provide reinforcement against the internal pressure of the bellows, hence limiting the lateral deflection. These rings are constructed from tubing or solid round bars of carbon steel, stainless steel, or other suitable alloys, and are composed of these materials.


Click here to read more :  Control Rods / Limit Rods /  Tie Rods / Bellows /  Pantographic linkages /  Protective cover / Purge Connector.