Calculation and calculation formula of minimum inlet pressure NPSH for stainless steel vertical multistage pump
If the pressure in the stainless steel vertical multistage pump is lower than the vapor pressure of the conveying liquid, cavitation may occur. To avoid cavitation, ensure that there is a minimum pressure on the inlet side of the pump. The maximum suction stroke H[m] can be calculated by the following formula:
H-Pbx 10.2-NPSH-Hf-Hv-Hs
Pb=Atmospheric pressure [bar] (Atmospheric pressure can be set to 1bar)
In a closed system, Pb is the system pressure [bar]
NPSH=Net positive suction head [m] (can be read from the maximum possible flow of the pump on the NPSH curve)
Hf=piping loss at the inlet [m]
Hv=steam pressure [m]
Hs=safety margin-minimum 0.5m head
If the calculated H is a positive value, the pump can run at the maximum suction lift H.
If the calculated H is negative, there must be a minimum inlet pressure H head.
