Pump Performance curvePump performance curves are the least used, least consulted, least appreciated, and least understood aspect of the world of industrial pumps.In reality, the performance curve is easy to understand. It isnt rocket science.The performance curve indicates that the pumpwill discharge A certain volume or flow (m3/hr) of a liquid, At a certain pressure or head (H). 4E4O4CO C 4E M4E Q4 4 4O4MOEE+4 4 EM CE+4 4ME4OO*O4CO+4 Q4 +M4 444O 4E OE4 M 4 4 E4Q4 M+4 OMC4 E CEM+4E By definition, the pump is a machine designed to add energy to a liquid with the purpose of elevating it or moving it through a pipe. The pump can elevate a liquid in a vertical tube up to a point where the weight of the liquid and gravity will permit no more elevation.Theres a language barrier between the pump manufacturers and the pump users.They use different terminology. Pump users, operators and mechanics, use pressure gauges that read in bar, kg/cm2 etc.The pump manufacturer denotes pressure in meters of head ( mlc).mlc : meters of liquid columnTherefore when we operate a centrifugal pump we have to calculate the Total head of the pump.Using the following formulaManometric pressure is the difference of discharge and suction manometers.Keep in mind always :If suction gauge is below zero (vacuum)Manometric pressure = Discharge + suctionIf suction gauge is above zero (positive suction)Manometric pressure = Discharge - suctionEasy formulasBut in LPGs things are WORSE[ (PD - PT) + PL] x 10,2SG+ HM - HLTotal head calculation in LPG shipPump discharge pressure calculation in LPG ship[ (TH - HM) + HL] x SG10,2+ PT - PLGiven :PD= Discharge gauge pressure ( bar ) = 7,5 barPT= Tank pressure ( bar ) = 0,03 barPL= Pump column losses ( bar ) = 0,2 barSG = Specific gravity ( kg/dm3 ) = 0,6815 @ -33,2 CHM = Discharge pressure gauge height ( mtrs ) = 18,3 mtrsHL = Tank Sounding level ( mtrs ) = 13,5 mtrsRequired :TH = 120 mlc TH= Total Head ( mlc ) [ (PD - PT) + PL] x 10,2SGTH = + HM - HL[ (7,5 0,03) + 0,2] x 10,20,6815TH = + 18,3 13,5BEPQ= m3 /hrTH= mlcThe pump is designed for a discrete value of flow rate, differential head, and speed.This is the Best Efficiency Point of operation.B E PHowever,in practical applications, the pumps are rarely operated at the operating parameters for which the pump has been designed.Given :TH= Total Head ( mlc ) = 120 mlcPT= Tank pressure ( bar ) = 0,03 barPL= Pump column losses ( bar ) = 0,2 barSG = Specific gravity ( kg/dm3 ) = 0,6815 @ -33,2 CHM = Discharge pressure gauge height ( mtrs ) = 18,3 mtrsHL = Tank Sounding level ( mtrs ) = 13,5 mtrs[ (TH - HM) + HL] x SG10,2+ PT - PLRequired :PD = PD= Discharge gauge pressure ( bar )[ (120 18,3) + 13,5] x 0,6815+ 0,03 0,2 PD = 10,2PD = 7,53 bar In the final analysis,Pumps should be operated at or near their BEP.These pumps will run for years without giving problems. The pump curve is the pumps control panel, and it should be in the hands of the personnel who operate the pumps and understood by them.In case you have understand what we just saidThen you can use my application to calculate the Total head and required gauge pressure. Thank you