A Universal Expansion Joint consist of a universal bellow with two pairs of hinges. This type of expansion joint is used to accommodate large amount of lateral deflection in one plane. By providing a special arrangement of hinge box, the Universal Hinge Expansion Joint can also accommodate angular movement and lateral deflection in more than one plane.
Un- Restrained Universal expansion joint:
Unrestrained Universal Expansion Joints can absorb large amount of lateral deflections in addition to axial and angular movements. The applications which has large amount of lateral deflection, the length of the centre piece can be increased to accommodate it. Usually Universal expansion joints are provided with control rods to distribute the movement equally between the two bellows. Control rods are not designed to withstand pressure thrust.
Restrained Type Universal expansion joint:
It is same as unrestrained type expansion joint, but with addition of tie-rods. These tie rods are designed to withstand the pressure thrust and so the external movement of the expansion joint is constrained even if the pressure thrust is increased. If the expansion joint has to accommodate angular movement, in one plane only two tie rods are provided 180 degree apart. To restrict this angular movement, four tie rods are provided at in interval of 90 degrees, around the circumference of the expansion joint.
- Lateral motion in one/or more than one plane.
- Eliminates pressure thrust as it is restrained by the hinge pins.
- Prevents torsional movement of the expansion joint.
- Eliminates requirement of the main anchors.
- Requires minimum guiding supports.
- Reduces forces on the piping arrangement.
- Designed to restrain extraneous forces like wind loads, dead loads, weight of machinery, etc.
- Movement can be controlled.
- Angular deflection, if designed.