The impeller is a disk with blades that makes a liquid flow by aspirating it from a pipe and pushing it into another pipe through the centrifugal force. The impeller is a rotating component that is moved by the axis of the motor and increases the prevalence, pressure and flow of the liquid (depending on the characteristics of the impeller, such as thickness or diameter). The impellers can be made of different material, metal (cast iron, bronze, steel) or technopolymer (eg Noryl or Ultem); the impeller differ for uses (low / high temperatures, corrosion resistance, different pH, etc.). The presence of several impellers increases the prevalence and pressure.