Turbine refers to a wide range of impellers without regard to design, direction of discharge, or character of flow. Turbines include both axial and radial designs. A turbine is an impeller with two or more blades at a constant blade angle over its entire length. Blades may be either vertical or set at an angle less than 90°. Blades can be flat or curved.
Unlike the turbine, these blades do not maintain a constant blade angle over their length. These blades which include propellers and hydrofoils are considered axial flow impellers. The profile and angle of these blades vary across their length.
While basically a turbine-type blade, the paddle draws its distinction from its large Diameter/Tank Ratio. These impellers are run in the laminar flow region, or in the transition and turbulent regions, paddles are run without baffles. In high viscosities, paddles are run in conjunction with other blades.
These impellers are extremely effective at powder dispersion and emulsion. They are characterized as low-flow high-velocity impellers. These impellers are primarily radial discharging. The high operating speed of the dispersion blade results in high power input. As limited flow is induced power input results in high shear.