For limited material volume BATCH mixing is used
For large material volume CONTINOUS mixing is preferred
The flow pattern during mixing may be Radial (perpendicular), Axial (parallel ) to the shaft or Tangential ( tangential to the circle of rotation around the shaft)
Based on the flow pattern they produce, on shape and pitch of the blades , the are classified into 3 types:
Propellers
Turbines
Paddles