Suppressing device for a vertical pump, vertical pump and method for retrofitting a vertical pump

A suppressing device for shifting a structural natural frequency of a vertical pump, the pump including a pumping unit with an inlet and an impeller for conveying a fluid, a discharge unit with an outlet for the fluid, a drive unit for rotating the impeller, a column pipe extending in an axial direction and having at least one column element with an axial length, the column pipe connecting the pumping unit with the discharge unit, and a line shaft extending within the column pipe operatively connecting the drive unit with the pumping unit, the suppressing device comprising

• at least one rib extending essentially in a radial direction, and being perpendicular to an axial direction of the suppression device,
• the suppression device having an extension extending in the axial direction of the suppressing device, being at least half the axial length of the at least one column element, and being configured to closely fit around an entire circumference of the at least one column element.