Centrifugal Pump Handbook

304 Pages·2010·8.582 MB·English

by  Sulzer Pumps Ltd.

Centrifugal Pump
Handbook
Third edition
Sulzer Pumps Ltd
Winterthur, Switzerland
AMSTERDAM.BOSTON.HEIDELBERG.LONDON
NEWYORK.OXFORD.PARIS.SANDIEGO
SANFRANCISCO.SINGAPORE.SYDNEY.TOKYO
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Secondedition1998
Thirdedition2010
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Preface
This new edition of the Centrifugal Pump Handbook takes full account
of the recent progress that has been made in pump construction and
technology.
. Closecontactwiththemarkethasopenedupnewfieldsofapplication.
. Consistentevaluationofoperatingexperience,backedbycontinuous
collaborationwithpumpusers,hasledtoimprovedoperatingperfor-
manceandreliability.
. Intensified research and development using powerful computer
modelingtoolsinareassuchascavitation,rotordynamicsandmate-
rialstechnologyhaveledtosteeprisesinoutput.
TheaimoftheHandbookistoprovideanoverviewofthecurrentstate
oftheartinpumpconstruction.Itisintendedforplannersandoperating
companiesalike.Tomakethecontentaccessiblewehaveincludedthe
mostimportantinformationbutinsomeinstanceslimitedthedegreeof
detailprovidedtothatwebelieveismostcommonlyrequired.
Alltheexperiencegainedbyourselvesandothersintheindustryhas
been assembled and related to various common fields of application.
Problemaspectssuchascavitation,erosion,selectionofmaterials,rotor
vibration behavior, forces acting on pumps, operating performance in
various systems, drives, acceptance testing and many more are dealt
withindetail.
TheHandbook isthe productof collaboration bymany membersof
the Sulzer Pumps team and we take this opportunity to thank all our
personnelfortheirsupportinthisproject.
xiii
Contents
Preface ..............................................................xiii
1 PhysicalPrinciples...........................................1
1.1 Energyconversionincentrifugalpumps .......................1
1.2 Power,lossesandefficiency ..................................3
1.3 Totalheadofthepump .......................................5
1.4 Thetotalheadrequiredbyapumpingplant ...................6
1.5 Cavitationandsuctionbehavior ...............................7
1.5.1 Physicalprinciples.................................... 7
1.5.2 Netpositivesuctionhead(NPSH) ..................... 8
1.5.3 AvailableplantNPSH ................................ 12
1.5.4 Methodsofimprovingsuctionperformance .......... 14
1.5.5 Cavitationerosion ................................... 14
1.6 Modellawsandsimilaritycoefficients ....................... 15
1.7 Axialthrust ................................................. 16
1.8 Radialthrust................................................ 22
1.9 Rotordynamics............................................. 23
2 BehaviorofCentrifugalPumpsinOperation............... 27
2.1 Characteristicsofcentrifugalpumps ........................ 27
2.2 Controlofcentrifugalpumps ................................ 28
2.2.1 Pipingsystemcharacteristic ......................... 28
2.2.2 Pumpcontrol........................................ 28
2.2.2.1 Throttling ...................................30
2.2.2.2 Startingandstoppingpumps................32
2.2.2.3 Bypasscontrol..............................35
2.2.2.4 Speedcontrol...............................36
2.2.2.5 Impellerbladeadjustment...................38
2.2.2.6 Pre-rotationcontrol .........................38
2.2.2.7 Cavitationcontrol ...........................41
2.3 Matchingcharacteristicstoservicedata .................... 41
2.3.1 Reductionofimpellerdiameter(impellertrimming).... 41
2.3.2 Sharpeningofimpellerbladetrailingedges........... 43
2.4 Torque/speedcurves ....................................... 44
2.4.1 Startingtorqueofcentrifugalpumps ................. 44
2.4.2 Startup(excludingpressuresurge) ................... 46
2.4.2.1 Startupagainstclosedvalve ................46
2.4.2.2 Startupagainstclosednon-returnvalve
withthedischargevalveopen ...............46
2.4.2.3 Startupwithdischargevalveopenbutno
statichead..................................46
v
vi Contents
2.4.2.4 Startupwithdischargevalveopenand
pressurepipelinedrained ...................47
2.5 Startuptimeforacentrifugalpump.......................... 48
2.6 Rundowntimeforacentrifugalpump(disregarding
thepressuresurge) ......................................... 49
2.7 Pumpingspecialliquids..................................... 50
2.7.1 Viscousliquids ...................................... 50
2.7.1.1 Viscositydefinitions .........................50
2.7.1.2 Pumpingviscousliquids ....................52
2.7.1.3 Simplifiedinstructionsfordetermining
pumpperformanceonaviscousliquid
whenperformanceonwaterisknown .......54
2.7.2 Gas/liquidmixtures .................................. 56
2.7.3 Pumpinghydrocarbons .............................. 58
2.7.3.1 Influenceonsuctioncapacity(NPSH)........58
2.7.4 Handlingsolid–liquidmixtureswith
centrifugalpumps ................................... 59
2.8 Minimumflowrate .......................................... 64
2.8.1 Determiningtheminimumflowrate .................. 64
2.8.1.1 Admissibletemperaturerise.................64
2.8.1.2 Poorhydraulicbehaviorinthepartloadrange 67
2.8.1.3 Influenceofaxialandradialthrust ...........68
3 AcceptanceTestswithCentrifugalPumps ................ 69
3.1 Preliminaryremarks......................................... 69
3.2 Pumptests ................................................. 69
3.2.1 Acceptancerules .................................... 70
3.2.2 ComparisonofISO,API610andHydraulic
InstituteStandardswithregardtoguarantee
pointsandmeasuringuncertainties .................. 71
3.2.3 Testbeds ........................................... 72
3.2.4 Conversionoftestresults ............................ 75
3.2.5 Measuringinstrumentuncertainty .................... 76
3.2.6 Fulfillmentofguarantee .............................. 78
3.2.6.1 Allowingforthemeasuringuncertainties
inthetestevaluation ........................78
3.2.6.2 Fulfillingguaranteeswithradial,mixed
andaxial-flowpumpsaccordingtoISO......78
3.2.7 Testbedsandmeasuringinstruments................ 80
3.3 Axialthrustmeasurements.................................. 80
3.3.1 Reasonsformeasuringtheaxialthrust ............... 81
3.3.2 Axialforcetransducersemployed .................... 82
3.4 Radialthrustmeasurements ................................ 84
3.5 Efficiencydeterminationbythethermometric
measurements.............................................. 84
3.5.1 Methodsofmeasuringtemperature .................. 85
Contents vii
3.5.1.1 Measuringwithsamplingprobesand
quartzthermometer .........................86
3.5.1.2 Measuringtheoutsidepipetemperature.....87
4 SpecialDataforPlanningCentrifugal
PumpInstallations ......................................... 89
4.1 Intakedesignforverticalpumps ............................ 89
4.1.1 Flowconditions...................................... 89
4.1.1.1 Velocitydistribution .........................89
4.1.1.2 PlantNPSH .................................89
4.1.1.3 Formationofvortices........................89
4.1.1.4 Preventingpre-swirlinthepumpinlet........90
4.1.2 Designguidelines.................................... 91
4.1.2.1 Intakedesign ...............................91
4.1.2.2 Wetpitinstallations .........................92
4.1.2.3 Drypitinstallation ...........................93
4.2 Guidelinesforinletpipelines ................................ 98
4.2.1 Connectionofpipetosuctionreservoir............... 98
4.2.2 Designinginletpipelines ............................ 102
4.2.2.1 Preliminaryremarks ........................102
4.2.2.2 Designguidelines ..........................103
4.3 Pressuresurgesinpipelinesystems........................ 110
4.3.1 Causesofapressurechange ....................... 110
4.3.2 Fundamentals ...................................... 112
4.3.3 Calculatingthepressuresurge ...................... 114
4.3.4 Necessityforpressuresurgecalculation ............ 115
4.3.5 Protectivemeasures................................ 116
4.3.6 Flaphammer ....................................... 120
4.3.7 Examples .......................................... 120
4.3.8 Guaranteeandacceptancetest..................... 122
4.4 Monitoringandinstrumentationforcentrifugalpumps ...... 124
4.5 Noiseemissionfromcentrifugalpumps .................... 125
4.5.1 Basicacousticterminology ......................... 125
4.5.1.1 Acousticquantities.........................125
4.5.1.2 Levels .....................................126
4.5.1.3 Frequencyspectrum .......................127
4.5.1.4 Weightingcurves ..........................127
4.5.1.5 Summationofsoundlevels.................127
4.5.1.6 Correlationbetweensoundpower,sound
pressureandsoundintensity ...............128
4.5.2 Originsofnoisefrompumps ........................ 129
4.5.3 Measuringnoise .................................... 129
4.5.4 Sounddatafrommeasurements .................... 130
4.5.5 Methodsofabatingnoise ........................... 131
4.5.5.1 Pumpdrive ................................132
4.5.5.2 Structure-bornenoise ......................133
4.5.5.3 Piping .....................................133
viii Contents
4.5.5.4 Reducedemissionfromthepump..........133
4.5.6 Listofstandardsandguidelines..................... 134
4.6 Vibrationoncentrifugalpumps............................. 136
4.6.1 Introduction ........................................ 136
4.6.2 Measuringbearinghousingandshaftvibration ...... 137
4.6.3 Vibrationlimits...................................... 139
5 MechanicalComponents ................................. 145
5.1 Shaftcouplings............................................ 145
5.2 Bearings .................................................. 149
5.2.1 Rollingcontactbearings ............................ 149
5.2.2 Slidingcontactbearings ............................ 149
5.2.3 Hydrostaticradialandthrustbearings............... 151
5.3 Seals...................................................... 153
5.4 Pipeforces ................................................ 155
6 Pipelines,ValvesandFlanges ............................ 159
6.1 Pressurelosses............................................ 159
6.1.1 Pipelinenetworks................................... 159
6.1.1.1 Branchednetwork,comprisingpipelines
connectedinseriesandparallel ............159
6.1.2 Seriesandparalleloperationofpumps.............. 159
6.1.3 Establishingpressurelosscurves ................... 160
6.1.3.1 Establishingpressurelosscurves ..........162
6.1.4 Pipelinesingeneral ................................. 162
6.1.4.1 Selectionofthepipeinsidediameter .......162
6.1.4.2 Approximatevaluesforflowvelocitiesin
pipelinesupstreamanddownstream
ofthepump................................163
6.1.4.3 Calculatingpressurelossesin
straightpipelines ......................... 164
6.1.4.4 Pressurelossesinbranchloops ............171
6.1.4.5 Pressurelossesinbends...................172
6.1.4.6 Pressurelossesforpipeintakes ............175
6.1.4.7 Pressurelossesduetochanges
incross-section............................176
6.1.4.8 Pressurelossesinvalves...................180
6.2 Pipedimensions........................................... 182
6.3 Bibliography............................................... 183
7 CentrifugalPumpDrives .................................. 185
7.1 Electricmotors ............................................ 185
7.1.1 Characteristicsofthevariouselectricmotors........ 185
7.1.2 Three-phasemotors ................................ 185
7.1.2.1 General ....................................185
Contents ix
7.1.2.2 Applicationsforthree-phaseasynchronous
squirrel-cagemotors .......................185
7.1.2.3 Applicationsforthree-phaseasynchronous
motorswithslip-ringrotors.................186
7.1.2.4 Applicationsforthree-phase
synchronousmotors .......................186
7.1.3 Boundaryconditionsaffectingmotorsizing.......... 187
7.1.3.1 Requirementsimposedbythecentrifugal
pumponthemotor ........................187
7.1.3.2 Ambientconditions ........................187
7.1.3.3 Gridconnectiondetails.....................188
7.1.3.4 Specialspecifications ......................188
7.1.4 Startingcharacteristics ............................. 188
7.1.4.1 General ....................................188
7.1.4.2 Startingcharacteristicsofthree-phase
squirrel-cagemotors .......................189
7.1.4.3 Startingcharacteristicsofthree-phase
slip-ringinductionmotors ..................189
7.1.4.4 Startingcharacteristicsofthree-phase
synchronousmotors .......................189
7.1.5 Possiblestartingprocedures........................ 190
7.1.5.1 General ....................................190
7.1.5.2 Startingthree-phasesquirrel-cagemotors ..191
7.1.5.3 Startingthree-phaseslip-ring
inductionmotors ......................... 191
7.1.5.4 Starting three-phase synchronous
motors .................................. 192
7.1.6 Choiceofstartingmethodforthree-phasemotors... 193
7.1.6.1 General ....................................193
7.1.6.2 Provenstartingmethodsforsquirrel-cage
andsynchronousmotors ...................193
7.1.6.3 Comparisonofvariousstartingmethods....194
7.1.7 Speedcontrol/regulationofthree-phasemotors..... 194
7.1.7.1 Speedcontrolofthree-phase
squirrel-cagemotors .......................194
7.1.7.2 Speedcontrolofthree-phaseslip-ring
inductionmotors...........................195
7.1.7.3 Speedcontrolofthree-phase
synchronousmotors .......................196
7.1.8 Somefeaturesrelevanttothechoiceofinduction
motorsfordrivingcentrifugalpumps ................ 197
7.1.8.1 Three-phasecurrentorthree-phase
networkgrid ...............................197
7.1.8.2 Operatingvoltagesandgridfrequencies....198
7.1.8.3 Variationsofgridvoltageatconstant
gridfrequency .............................198
x Contents
7.1.8.4 Variationsofgridfrequencyatconstant
gridvoltage ................................198
7.1.8.5 Variationsofgridvoltageandgrid
frequencyoccurringsimultaneously ........199
7.1.8.6 Speedsofthree-phasemotorsatfrequencies
of50/60Hzforvariousnumbersofpoles ...200
7.1.8.7 Influenceofambienttemperatureand
locationaltitude............................200
7.1.8.8 Insulationclassification,operatinglife
ofwindings ................................201
7.1.8.9 Structuralconfigurationsof
three-phasemotors ...................... 202
7.1.8.10 Typesofprotectionforthree-phase
motorsaccordingtoIEC
Recommendation34–5andDIN40050.....202
7.1.8.11 Typesofcoolingforthree-phasemotors
(seeIECRecommendation34–6)...........203
7.1.8.12 Poweruptakebythree-phasemotors ......205
7.2 Dieselengines............................................. 206
7.2.1 General ............................................ 206
7.2.2 Operatingdataandoperatingfeatures .............. 206
7.2.2.1 Rotationspeed ............................206
7.2.2.2 Power .....................................207
7.2.3 Conditionsforinstallation ........................... 207
7.2.3.1 Fuel(dieseloil) .............................207
7.2.3.2 Disposalofexhaustgases .................207
7.2.3.3 Freshairrequirement ......................207
7.2.3.4 Coolingwaterrequirement .................208
7.2.3.5 Enginestartingmethods ...................208
7.2.3.6 Preheatingtheengine ......................208
7.2.3.7 Noiseemission ............................208
7.2.3.8 Torsionalvibrations ........................208
7.2.4 Applications ........................................ 209
7.3 Gasturbines............................................... 209
7.3.1 Introduction ........................................ 209
7.3.2 Thermodynamicprincipleandfeatures .............. 209
7.3.2.1 Workingprinciple ..........................209
7.3.2.2 Constructiontypes.........................211
7.3.3 Ratings............................................. 212
7.3.4 Fuels ............................................... 213
7.3.5 Environmentalprotection ........................... 214
7.3.5.1 Noiseemission ............................214
7.3.5.2 Exhaustgasemissions .....................215
7.3.6 Gasturbinesupportsystems ....................... 215
7.3.6.1 Startingsystem ............................215
7.3.6.2 Lubricatingoilsystem ......................215
Contents xi
7.3.6.3 Intakeairfiltration ..........................215
7.3.6.4 Monitoringandcontrolsystem .............215
7.3.7 Applicationaspumpdrive .......................... 216
7.3.7.1 Pipeline....................................216
7.3.7.2 Injection ...................................216
7.3.7.3 Loadingstations ...........................217
7.3.7.4 Applicationconsiderations .................217
7.4 Speedconverters.......................................... 218
7.4.1 Preliminarynotes ................................... 218
7.4.2 Variable-speedgearings/speedconverters
forcentrifugalpumps ............................... 218
7.4.2.1 Hydrodynamicspeedconverters
(alsocalledfluidorhydrauliccouplings).....218
7.4.2.2 Electromagneticspeedconverters .........224
8 MaterialsandCorrosion .................................. 227
8.1 Introduction ............................................... 227
8.2 Factorsaffectingcorrosion................................. 227
8.2.1 Thermodynamicsofthecorrosionprocess .......... 228
8.2.2 Kineticsofthecorrosionprocess ................... 229
8.2.2.1 Concentration..............................230
8.2.2.2 Temperature ...............................230
8.2.2.3 Masstransfer ..............................230
8.2.2.4 Potential ...................................231
8.2.2.5 Time.......................................231
8.3 Generalconsiderationsaffectingthechoiceofmaterial ..... 232
8.4 Formsofcorrosion ........................................ 233
8.4.1 General ............................................ 233
8.4.2 Uniformattack...................................... 235
8.4.3 Pittingcorrosion .................................... 235
8.4.4 Crevicecorrosion................................... 236
8.4.5 Intercrystallinecorrosion............................ 237
8.4.6 Galvaniccorrosion(contactcorrosion) .............. 239
8.4.7 Selectivecorrosion ................................. 239
8.4.8 Stresscorrosioncracking(SCC)and
corrosionfatigue.................................... 239
8.4.9 Erosioncorrosion................................... 240
8.4.10 Cavitationcorrosion ................................ 241
8.5 Corrosivepropertiesofliquidsbeingpumped .............. 243
8.6 Corrosionproblemsinhydraulicmachines ................. 246
8.7 Conclusions ............................................... 250
9 PrincipalFeaturesofCentrifugalPumps
forSelectedApplications ................................. 251
9.1 Oilandgas ................................................ 252
9.1.1 Injectionpumps .................................... 252