Expansion joints play a crucial part in many different systems. You’ll find them in piping systems, exhaust systems, and even in aeronautics. They are widespread and help to protect sensitive systems from undue strain caused by high temperature fluctuations and severe or constant vibrations.
Find out more about the components that create this ubiquitous device in this guide to expansion joint assembly terminology.
Bellows
The bellows is the flexible element of the expansion joint.
Control Rods
Control rods distribute movement between the two bellows of a universal expansion joint.
Convolution
A convolution is the smallest element of the bellows; its movement relates to the number of convolutions.
Reinforcing Rings
Reinforcing rings are sometimes used to reinforce the bellows from internal pressure.
Flanged Ends
Both ends of a joint have flanges to bolt the piece to the mating flanges of the piping or equipment it is attaching to.
Internal Sleeve
An internal sleeve reduces contact from the inner surface of the bellows and the fluid going through.
Limit Rods
Limit rods are responsible for restricting the bellows range of movement to prevent overextension or over-compression.
Purge Connections
Purge connections are located at sealed end of internal sleeve to allow for injections of liquid or gas.
Shipping Devices
Shipping devices are installed to maintain the joint length during shipping. They shouldn’t be used for testing.
Slotted Hinges
Slotted hinges are used in pairs to allow axial and one plane angular movement.
Stabilizer
A stabilizer’s main function is to make the joint more stable and is attached either internally or externally.
Tangents
Tangents are the straights parts at bellows’ ends.
Tie Rods
Tie rods restrain the bellows pressure continuously during operation.
Weld Ends
Weld ends are the ends of the joints used for welding to piping and other equipment.
Assembling expansion joints properly is vital to the success of any system. This guide to expansion joint assembly terminology will help you with installation and maintenance throughout the lifespan of the bellows. Learn more about custom bellows installation by exploring our blogs at Triad Bellows.
