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

Abstract

A suppressing device shifts a structural natural frequency of a pump, the pump including a pumping unit with an inlet and an impeller, a discharge unit with an outlet, 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 includes at least one rib extending essentially in a radial direction, and is perpendicular to an axial direction of the suppression device. The suppression device has an extension extending in the axial direction of the suppressing device, is at least half the axial length of the column element, and is configured to closely fit around an entire circumference of the column element.

1 . 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.   
     
     
         2 . The suppressing device in accordance with  claim 1 , wherein the extension in the axial direction is equal to the axial length of the column element around which the suppressing device is capable of fitting in the assembled state. 
     
     
         3 . The suppressing device in accordance with  claim 1 , further comprising a plurality of stiffening members curved in a circumferential direction and being connectable to each other and complementing one another in the assembled state so as to form a tubular structure for closely fitting around the entire circumference of the column element. 
     
     
         4 . The suppressing device in accordance with  claim 3 , wherein each stiffening member of the plurality of stiffening members has two lateral ribs extending in the radial direction, each rib of the two lateral ribs forming an end of a respective stiffening member with respect to the circumferential direction. 
     
     
         5 . The suppressing device in accordance with  claim 4 , wherein the plurality of stiffening members includes four stiffening members, each of stiffening members having a middle part with a quadrant shaped cross section, the middle part extending between the two lateral ribs. 
     
     
         6 . The suppressing device in accordance with  claim 4 , wherein each lateral rib of the two lateral ribs includes a plurality of holes configured to receive a fixing device to rigidly connect adjacent stiffening members. 
     
     
         7 . The suppressing device in accordance with  claim 4 , wherein at least one stiffening member of the plurality of stiffening members has an intermediate rib extending in the radial direction and being arranged between the two lateral ribs. 
     
     
         8 . A vertical pump for conveying the fluid, the vertical pump comprising:
 the pumping unit with the inlet and the impeller configured to convey the fluid;   the discharge unit with the outlet for the fluid;   the drive unit for rotating the impeller;   the column pipe extending in the axial direction and having the at least one column element with the axial length, the column pipe connecting the pumping unit with the discharge unit;   the line shaft extending within the column pipe and operatively connecting the drive unit with the pumping unit; and   the suppressing device designed according to  claim 1 , the suppressing device being configured to closely fit around the entire circumference of at least one column element, and having the extension in the axial direction at least half the axial length of the at least one column element.   
     
     
         9 . The vertical pump in accordance with  claim 8 , wherein the suppressing device is configured to be releasably connected to the at least one column element. 
     
     
         10 . The vertical pump in accordance with  claim 8 , wherein the extension of the suppressing device in the axial direction is equal to the axial length of the at least one column element. 
     
     
         11 . The vertical pump in accordance with  claim 8 , wherein the at least one column element includes a plurality of column elements, and the suppressing device is one of first and second suppressing devices, and the first and second suppressing devices are configured to couple to first and second column elements of the plurality of column elements, respectively. 
     
     
         12 . A method of retrofitting the vertical pump comprising the pumping unit with the inlet and the impeller for conveying the fluid, the discharge unit with the outlet for the fluid, the drive unit for rotating the impeller, the column pipe extending in the axial and having the at least one column element with the axial length, the column pipe connecting the pumping unit with the discharge unit, and the line shaft extending within the column pipe and operatively connecting the drive unit with the pumping unit, the method comprising:
 providing the suppressing device for shifting a structural natural frequency of the vertical pump, the suppressing device being designed in accordance with  claim 1 ,   selecting the at least one column element, and   mounting the suppressing device to the at least one column element in a closely fitting manner around the entire circumference of the column element.   
     
     
         13 . The method in accordance with  claim 12 , wherein the suppressing device includes an extension in the axial direction equal to the axial length of the at least one column element. 
     
     
         14 . The method in accordance with  claim 12 , wherein the suppressing device includes a plurality of stiffening members, and the stiffening members are disposed around the column element and fixed to each other so as to enable the suppressing device to closely fit around the entire circumference of the column element. 
     
     
         15 . The method in accordance with  claim 12 , wherein the at least one column element includes a plurality of column elements and the suppression device is one of a plurality of suppression devices, and each of the column elements is provided with a separate suppressing device of the plurality of suppression devices. 
     
     
         16 . The method in accordance with  claim 14 , wherein the plurality of stiffening members includes four stiffening members.