The choice of an agitator is sometimes a question rather complex to solve.

 Indeed, on the one hand, problems's data are essentially variable:

• nature of product to be mixed (liquids, solids, gas)
• physical characteristics of thee product (density, viscosity, unctiousness)
• capacity and shape of the tank …

 Of the other hand, the required aims are obviously not always the same ones: sometimes it is to ensure a low speed mixing to avoid a light sedimentation, sometimes an important turbulence will be absolutely necessary to generate and maintain the contact of two or several fluids.