Type:
untied universal expansion joint
Untied universal expansion joints and pantograph linkages untied universal
expansion joint can absorb large amount of lateral deflections in addition to axial
and angular movements. Usually these type of 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.
tied universal expansion joint
Tied universal expansion joint is same as untied universal expansion joints, 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. Angular movement can be accommodated only if
two tie rods are provided 180 degree apart. To restrict this angular movement, four
tie rods are provided at interval of 90 degrees, around the circumference of the
expansion joint.
Feature:
Absorbs large amounts of lateral deflection
Simple and robust construction
Eliminates pressure thrust load
Low maintenance
Application:
Universal expansion joints can absorb movements in all directions, and are used
in uncritical, low pressure installations like ventilation ducts, exhaust gas systems,
fresh air ventilation and process equipment.