Limiters / Length limiters / Tie rods
Rubber expansion joints should be considered as elastic elements in the pipelines in Design A (without tie rods), the rubber expansion joint creates reaction forces in the direction of expansion when subject to pressure (effective area x operating pressure), and reaction forces in the direction of compression when subject to negative pressure. These forces must be absorbed by the closest fixed points, radial plain bearings or the valve flange.
If this is not possible, there are a number of different length limiters that absorb the corresponding reaction forces but do not limit the expansion joint’s freedom of movement (with the exception of axial movement absorption). In the case of a design with tie rods, only the stiffness rates from the rubber bellow and the frictional force from the bearings need to be taken into account for the fixed points.