Transcription of Centrifugal Pump Vibrations - The Causes
1 Centrifugal Pump Vibrations :The CausesbySteven J. Hrivnak, Mechanical EngineerTennessee EastmanEastman Chemical CompanyEASTMANFAULTSREPORTEDOVER 3 YEARSV ibration: vibration :a measure of reliability!a measure of reliability!Poorlyinstalled and operated pumps in/secoverall vibrationand have6 months pumps in/secoverall vibrationand have60 months Basic Causes of PumpThree Basic Causes of PumpVibrations: Vibrations : Mechanically InducedMechanically Induced System InducedSystem Induced Operation InducedOperation InducedMechanically InducedMechanically Induced Bad bearingsBad bearings Bent ShaftBent Shaft Unbalanced RotorUnbalanced Rotor Check Valve Installed BackwardsCheck Valve Installed Backwards MisMis-Alignment-Alignment LoosenessLooseness Soft FootSoft Foot Maximum Size ImpellerMaximum Size ImpellerSystem InducedSystem Induced Partially/Plugged StrainerPartially/Plugged Strainer Clogged Impeller or Suction LineClogged Impeller or
2 Suction Line InstallationInstallationPIPING?Foundatio nsFoundationsandandBaseplatesBaseplatesT he mass ratio must be 3:1 toThe mass ratio must be 3:1 tominimize vibrationminimize vibrationOperationally InducedOperationally Induced CavitationCavitation FlowFlow SpeedSpeed Insufficient Immersion of Suction Pipe orInsufficient Immersion of Suction Pipe orBellBellCavitation and FlowCavitation and FlowOperating Off The can t run a pump with suctionYou can t run a pump with suctionand discharge valves closed!and discharge valves closed!Minimum FlowMinimum Flow1750 rpm 15-20% BEP Flow1750 rpm 15-20% BEP Flow3500 rpm 30-50% BEP Flow3500 rpm 30-50% BEP FlowMaximum FlowMaximum Flow110-115% BEP Flow110-115% BEP FlowSpeedSpeedSuction Pipe ImmersionSuction Pipe ImmersionEASTMANA void Max Size ImpellersAvoid Max Size ImpellersConclusionsConclusionsEASTMANA void Max Size ImpellersAvoid Max Size ImpellersKeep speed to 1750 maxKeep speed to 1750 maxConclusionsConclusionsEASTMANA void Max Size ImpellersAvoid Max Size ImpellersKeep speed to 1750 maxKeep speed to 1750 maxKeep flow in
3 Design rangeKeep flow in design rangeConclusionsConclusionsEASTMANA void Max Size ImpellersAvoid Max Size ImpellersKeep speed to 1750 maxKeep speed to 1750 maxKeep flow in design rangeKeep flow in design rangeGrout your baseplatesGrout your baseplatesConclusionsConclusionsEASTMANA void Max Size ImpellersAvoid Max Size ImpellersKeep speed to 1750 maxKeep speed to 1750 maxKeep flow in design rangeKeep flow in design rangeGrout your baseplatesGrout your baseplatesUse proper pipingUse proper pipingConclusionsConclusionsEASTMANA void Max Size ImpellersAvoid Max Size ImpellersKeep speed to 1750 maxKeep speed to 1750 maxKeep flow in design rangeKeep flow in design rangeGrout yourGrout yourbaseplatesbaseplatesUse proper pipingUse proper pipingAvoid hydraulically induced problems likeAvoid hydraulically induced problems likecavitation, and suction and discharge re-circulation,cavitation, and suction and discharge re-circulation, pumps - 6 YR.
4 MTBF8 pumps - 5 YR. MTBF15 pumps - 4 YR. MTBF5 pumps - 6 YR. MTBF8 pumps - 5 YR. MTBF15 pumps - 4 YR. MTBF
