PURPOSE: To suppress vibrations in the direction of a shell axis and in the direction rectangular to the shell axis by assembling vibration inhibitors of the pressure vessel such as a heat exchanger, a moisture separator or the like, independently in the direction of a shell axis and the direction rectangular to the shell axis in the inner part of a shell support base.

CONSTITUTION: A vibration inhibitor for inhibiting vibrations in the direction a shell axis comprises a vibration inhibitor cylinder part 5, a piston shaft 6 and a piston 7 mounted thereon. The inside of the cylinder part 5 is filled with oil, and oil is movable between both sides of the piston 7 through an orifice 8. Therefore, the cylinder part 5 does not permit the moving of oil due to viscosity and acts as a vibration inhibitor with respect to the abrupt variation of force such as earthquake. Similarly, the vibration inhibitor for inhibiting vibrations in the direction rectangular to the axis comprises a shell supporting part 12, a piston 13, and a cylinder 14, and a coil spring 15 mounted on a support part 12. Thus, by assembling vibration inhibitors independently in the axial direction of the shell and in the direction perpendicular to the axis of the shell, it is possible to prevent softly the thermal elongation in the direction of the shell axis, and at the same time, it is possible to softly suppress the thermal deformation of a pipeline by the displacement of the vibration inhibitor in the direction rectangular to the axis.