Description: Distance of the absolute static energy level above the energy level of the vapor pressure at the associated material temperature, referred to the (NPSH) reference plane.; Name: NPSH
Description: amount of the absolute value of the total head above the head, equivalent to the vapour pressure of the liquid at the particular temperature, with reference to the NPSH datum plane; Name: net positive suction head
Description: variable quantity, which is not influenced by the control but is introduced into the control system from outside with the aim of making the final controlled variable follow it in a given relationship; Name: command variable