1. Definition:

The universal expansion joint contains two bellows, which are joined by a middle pipe or connector for the purpose of absorbing any combination of the three basic movements: axial movement (x-axis), lateral movement (y-axis, z-axis) and angular rotation (θ). Universal expansion joint is usually designed with control rods to distribute the movement between the two bellows of the expansion joint and stabilize the middle pipe.

2. Advantages of universal expansion joint:

2.1 Absorb large amounts of lateral movement:
Each bellows separated by a middle pipe can absorb the offset & angular thermal movement. The amount of lateral movement capability can be increased or decreased by simply changing the length of the center pipe.

2.2 Tie rods can be designed to restrict and control motion, support weight:
Where these types are used it is necessary to consider and manage the resultant forces created by internal pressure using appropriate anchors, guides and supports.

3. Applications:
A universal expansion joint is used to absorb motion in multiple planes, and its application includes settling tank and seismic building separations. This is a very application for large diameter hot piping systems.

4. General safety recommendations:
Prior to installation and start-up, CDI-Bellows installation and start-up instructions must be read and observed.