Angular movement is the rotational displacement of the longitudinal axis of the bellows toward a point of rotation or flexion of the expansion joint along its center line.
Angular expansion joints are those that are equipped with hinges or cardan that allow absorbing the angular movement for which they are designed and restrict the internal pressure thrust. They absorb angular movement in a single plane when equipped with hinges and angular movement in several planes when equipped with a cardan system.
The most commonly used expansion joints to absorb angular movements are the following:
This model is designed to absorb lateral and angular movements in only one plane.
It is made up of two bellows joined together by a linking pipe and fitted with welding ends or flanges plus a double articulated system.
The hinge mechanisms are designed to contain pressure thrust.
Gimbal Expansion Joints are designed to allow angular movement in any plane by the use of two pairs of hinges affixed to a common floating gimbal ring. The gimbal ring, hinged and pins are designed to restrain the pressure thrust due to internal pressure and shear forces.
A gimbal ring is either round or square. For round gimbals the torsional moment shall be considered and for square gimbals the instability due to the bending shall be considered.
Designed to absorb lateral and angular movements in any direction. This model is made up of two bellows joined together by a linking pipe and a double cardan system.
A double gimbal expansion joint is basically a two single gimbal expansion joints and an intermediate pipe that joins them. This type of Expansion Joint can absorb a large lateral movement in any plane and angular movement in any direction.