![[How to read a positive displacement pump curve.jpg]] ## Slip slip = internal recirculation of low viscosity fluid from the discharge side of the pump back to the suction side of the pump > Once viscosity is over 1000 cPs, slip basically doesn’t occur in liquid sanitary pumps. If slip is not a factor, use the 0 PSI line to determine flow rate. > ![[_Users_isabelburgos_Documents_Obsidian_Notes_bin_Linked Files_How-to-read-a-positive-displacement-pump-curve-Figure-2.jpg]] ## Power Brake horsepower (BHP): power to overcome discharge pressure Work horsepower (WHP): power to achieve desired flow rate considering pressure drop from system componenets (valves, heat exchanges, filters, etc.) Viscous/internal horsepower (VHP): power to force internal parts of pump to turn, given fluid viscosities ![[_Users_isabelburgos_Documents_Obsidian_Notes_bin_Linked Files_How-to-read-a-positive-displacement-pump-curve-Figure-4.jpg]] ## NPSH Net Positive Suction Head required (NPSHr): miniminum pressure required on suction side to avoid cavitation Net Positive Suction Head available (NPSHa) is determined by process piping make sure **NPSHa > NPSHr** !