In vertical shaft flocculator, impeller is attached to a vertical shaft.
The shaft is rotated by an external gear reducer powered by an electric
motor capable of running at various speeds using a variable frequency drive.
The impellers are broadly classified as radial flow impeller and axial flow
impellers, depending upon the flow pattern. Radial flow impeller directs flow
outward from the impeller blades in horizontal direction. Axial flow impeller
directs the flow parallel to the vertical shaft. Axial flow impellers can be
upward pumping or downward pumping type.
The vertical shaft flocculators with axial flow impeller are generally used
for flocculation process in water treatment. They can be classified based on
the design of the blade: