Bellows expansion joint accessories

Bellows Expansion Joint Accessories 

         For universal bellows expansion joint,it usually composite by middle bellows,flanges in two ends,inner sleeve, tie rods,ear plate. When customer require add the outer cover and shrouds , we can also design and produce . Now , we introduce the main accessories as follow :  

Liners(Internal Sleeves)

When any of the following conditions exist:

A. When pressure drop must be minimized and smooth flow is essential.

B. When turbulent flow is generated upstream of the expansion joint by changes in flow direction. 

C. When it is neccessary to protect the bellows from media carrying abrasive materials such as catalyst or slurry. 

D. In high temperature applications to reduce the temperature of the bellows.The liner is a barrier between the media and the bellows.

E. For Air,Steam and other Gases 

Flow liners can trap liquid if the expansion joint is installed with the flow vertical up.On this case the internal sleeve are provided with drain holes to prevent liquid buildup under the liner.For custom designs,flow direction should always be provided.

Protective Covers and Shrouds

Covers and shrouds can be provided either fixed or removable.Fixed types are used where high velocity external steam conditions exist such as in condenser heater connections. The removable type is the Fustar standard and permits periodic in service inspection.They are also used to prevent damage during installation and operation or when welding is going to be performed in the immediate vicinity.If the bellow expansion joint is going to be externally insulated,a cover should be considered.Fustar always recommends covers for any expansion joint.The small cost increase is just economical insurance when compared to a complete joint replacement. 

Tie Rods 

Ties rods are devices,usually in the form of bars or rods,attached to the expansion joint assembly and are designed to absorb pressure loads and other extraneous forces like dead weight.When used on a single or universal style expansion joint,the ability to absorb axial movement is lost.

Limit Rods

Limit rods are used to protect the bellows from movements in excess of design that occasionally occurs due to plant malfunction or the failure of an anchor.LIMIT RODS DO NOT CONTAIN THE PRESSURE THRUST DURING NORMAL OPERATION.Limit rods are designed to prevent bellows over-extension or over-compression while restraining the full pressure loading and dynamic forces generated by an anchor failure.During normal operation the rods have no function. 

Purge Connections 

Purge connections are used in conjunction with internal liners to lower the skin temperature of the bellows in high temperature applications such as catalytic cracker bellows.The purge media can be air or steam which helps flush out particulate matter between bellows and the liner.This also prevents the build up of harmful solids in the convolutions that may stop the bellows from performing.