Expansion Joint


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.


INTERNAL LINERS:


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 joint. 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.


2. WELDED ENDS:


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

pipes.


3. FLANGES:


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.


4. CORSETS:


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.


5. HOLLOW REINFORCING RING:


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.


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