The head of the pump is the unit weight that the pump is pumping from the inlet of the pump (pump inlet flange) to the pump outlet (pump outlet flange). Which is the efficient energy that a Newtonian liquid gets through the pump. The unit is N, m/N = m, the height of the liquid column pumping the liquid, which is referred to as rice.

By definition, the pump head can be written as

                              H = Ed - Es

The Ed- energy of the liquid at the outlet of the pump (m);

       Es - energy of liquid at the pump inlet (m)。