An axial flow pump, or AFP, is a common type of water pump that essentially consists of a propeller in a tube. The propeller can be driven directly by a sealed motor in the tube or by a right-angle drive shaft that pierces the tube.
The main advantage of an AFP is that it can easily be adjusted to run at peak efficiency at low-flow/high-pressure and high-flow/low-pressure by changing the pitch on the propeller.
These pumps have the smallest of the dimensions among any of the conventional pumps and are more suited for low heads and higher discharges.
Figure 2 : Characteristic curve of an axial flow pump. Red lines show the different performance at varying blade pitch, blue lines the absorbed power.
An application example of an AFP would be transfer pumps used for sailing ballast. In chemical industry, they are used for the circulation of large masses of liquid, such as in evaporators and crystallizers.
