pumps & pumping systems

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  • *Pumps & Pumping Systems

    By SUDHIR REDDY S.V.R M.TECH(CAD/CAM)

  • * UNEP 2006Training Agenda: PumpsIntroductionType of pumpsAssessment of pumpsEnergy efficiency opportunitiesElectrical Equipment/Pumps

  • * UNEP 2006Introduction20% of worlds electrical energy demand25-50% of energy usage in some industriesUsed forDomestic, commercial, industrial and agricultural servicesMunicipal water and wastewater servicesWhat are Pumping SystemsElectrical Equipment/Pumps

  • * UNEP 2006IntroductionObjective of pumping systemWhat are Pumping SystemsElectrical Equipment/Pumps(US DOE, 2001)Transfer liquid from source to destinationCirculate liquid around a system

  • * UNEP 2006IntroductionMain pump componentsPumpsPrime movers: electric motors, diesel engines, air systemPiping to carry fluidValves to control flow in systemOther fittings, control, instrumentationEnd-use equipmentHeat exchangers, tanks, hydraulic machinesWhat are Pumping SystemsElectrical Equipment/Pumps

  • * UNEP 2006IntroductionHeadResistance of the systemTwo types: static and friction

    Static headDifference in height between source and destinationIndependent of flow Pumping System CharacteristicsElectrical Equipment/Pumps

  • * UNEP 2006IntroductionStatic head consists ofStatic suction head (hS): lifting liquid relative to pump center lineStatic discharge head (hD) vertical distance between centerline and liquid surface in destination tankStatic head at certain pressurePumping System CharacteristicsElectrical Equipment/PumpsHead (in feet) = Pressure (psi) X 2.31 Specific gravity

  • * UNEP 2006IntroductionFriction headResistance to flow in pipe and fittingsDepends on size, pipes, pipe fittings, flow rate, nature of liquidProportional to square of flow rateClosed loop system only has friction head (no static head)Pumping System CharacteristicsElectrical Equipment/Pumps

  • * UNEP 2006IntroductionIn most cases:Total head = Static head + friction headPumping System CharacteristicsElectrical Equipment/Pumps

  • * UNEP 2006Training Agenda: PumpsIntroductionType of pumpsAssessment of pumpsEnergy efficiency opportunitiesElectrical Equipment/Pumps

  • * UNEP 2006Type of PumpsClassified by operating principlePump ClassificationElectrical Equipment/Pumps

  • * UNEP 2006Type of PumpsPositive Displacement PumpsElectrical Equipment/PumpsFor each pump revolutionFixed amount of liquid taken from one endPositively discharged at other endIf pipe blockedPressure risesCan damage pumpUsed for pumping fluids other than water

  • * UNEP 2006Type of PumpsPositive Displacement PumpsElectrical Equipment/PumpsReciprocating pumpDisplacement by reciprocation of piston plungerUsed only for viscous fluids and oil wellsRotary pumpDisplacement by rotary action of gear, cam or vanesSeveral sub-typesUsed for special services in industry

  • * UNEP 2006Type of PumpsDynamic pumpsElectrical Equipment/PumpsMode of operationRotating impeller converts kinetic energy into pressure or velocity to pump the fluidTwo typesCentrifugal pumps: pumping water in industry 75% of pumps installedSpecial effect pumps: specialized conditions

  • * UNEP 2006Type of PumpsCentrifugal PumpsElectrical Equipment/PumpsHow do they work?(Sahdev M)Liquid forced into impellerVanes pass kinetic energy to liquid: liquid rotates and leaves impellerVolute casing converts kinetic energy into pressure energy

  • * UNEP 2006Type of PumpsCentrifugal PumpsElectrical Equipment/PumpsRotating and stationary components(Sahdev)

  • * UNEP 2006Type of PumpsCentrifugal PumpsElectrical Equipment/PumpsImpellerSahdev)Main rotating part that provides centrifugal acceleration to the fluidNumber of impellers = number of pump stagesImpeller classification: direction of flow, suction type and shape/mechanical constructionShaftTransfers torque from motor to impeller during pump start up and operation

  • * UNEP 2006Type of PumpsCentrifugal PumpsElectrical Equipment/PumpsCasingsVolute Casing (Sahdev)FunctionsEnclose impeller as pressure vesselSupport and bearing for shaft and impellerVolute caseImpellers inside casingsBalances hydraulic pressure on pump shaftCircular casingVanes surrounds impellerUsed for multi-stage pumps

  • *Impeller Mechanism Pump

  • *Diaphragm Pump

  • *Gear Pump

  • *Gear Pump Balanced

  • *Vane Pump

  • *Piston Pump

  • *Bent Axis Piston Pump

  • *Swash Plate Piston Pump

  • * UNEP 2006Training Agenda: PumpsIntroductionType of pumpsAssessment of pumpsEnergy efficiency opportunitiesElectrical Equipment/Pumps

  • *Assessment of pumpsPump shaft power (Ps) is actual horsepower delivered to the pump shaft

    Pump output/Hydraulic/Water horsepower (Hp) is the liquid horsepower delivered by the pumpHow to Calculate Pump PerformanceElectrical Equipment/PumpsHydraulic power (Hp):Hp = Q (m3/s) x Total head, hd - hs (m) x (kg/m3) x g (m/s2) / 1000

    Pump shaft power (Ps):Ps = Hydraulic power Hp / pump efficiency Pump

    Pump Efficiency (Pump): Pump = Hydraulic Power / Pump Shaft Power UNEP 2006hd - discharge headhs suction head, - density of the fluidg acceleration due to gravity

  • * UNEP 2006Assessment of pumpsAbsence of pump specification data to assess pump performanceDifficulties in flow measurement and flows are often estimatedImproper calibration of pressure gauges & measuring instrumentsCalibration not always carried outCorrection factors usedDifficulties in Pump AssessmentElectrical Equipment/Pumps

  • * UNEP 2006Energy Efficiency OpportunitiesSelecting the right pumpControlling the flow rate by speed variationPumps in parallel to meet varying demandEliminating flow control valveEliminating by-pass controlStart/stop control of pumpImpeller trimming Electrical Equipment/Pumps

  • * UNEP 2006Energy Efficiency Opportunities1. Selecting the Right PumpElectrical Equipment/PumpsPump performance curve for centrifugal pumpBEE India, 2004

  • * UNEP 2006Energy Efficiency Opportunities1. Selecting the Right PumpElectrical Equipment/PumpsOversized pumpRequires flow control (throttle valve or by-pass line)Provides additional headSystem curve shifts to leftPump efficiency is reducedSolutions if pump already purchasedVSDs or two-speed drivesLower RPMSmaller or trimmed impeller

  • * UNEP 2006Energy Efficiency Opportunities2. Controlling Flow: speed variationElectrical Equipment/PumpsExplaining the effect of speedAffinity laws: relation speed N andFlow rate Q NHead H N2Power P N3Small speed reduction (e.g. ) = large power reduction (e.g. 1/8)

  • * UNEP 2006Energy Efficiency OpportunitiesElectrical Equipment/PumpsVariable Speed Drives (VSD)Speed adjustment over continuous rangePower consumption also reduced!Two typesMechanical: hydraulic clutches, fluid couplings, adjustable belts and pulleysElectrical: eddy current clutches, wound-rotor motor controllers, Variable Frequency Drives (VFDs)2. Controlling Flow: speed variation

  • * UNEP 2006Energy Efficiency OpportunitiesElectrical Equipment/PumpsBenefits of VSDsEnergy savings (not just reduced flow!)Improved process controlImproved system reliabilityReduced capital and maintenance costsSoft starter capability2. Controlling Flow: speed variation

  • * UNEP 2006Energy Efficiency Opportunities3. Parallel Pumps for Varying DemandElectrical Equipment/PumpsMultiple pumps: some turned off during low demandUsed when static head is >50% of total headSystem curve does not changeFlow rate lower than sum of individual flow rates(BPMA)

  • * UNEP 2006Energy Efficiency Opportunities4. Eliminating Flow Control ValveElectrical Equipment/PumpsClosing/opening discharge valve (throttling) to reduce flowHead increases: does not reduce power useVibration and corrosion: high maintenance costs and reduced pump lifetime(BPMA)

  • * UNEP 2006Energy Efficiency Opportunities5. Eliminating By-pass ControlElectrical Equipment/PumpsPump discharge divided into two flowsOne pipeline delivers fluid to destinationSecond pipeline returns fluid to the sourceEnergy wastage because part of fluid pumped around for no reason

  • * UNEP 2006Energy Efficiency Opportunities6. Start / Stop Control of PumpElectrical Equipment/PumpsStop the pump when not neededExample: Filling of storage tankControllers in tank to start/stopSuitable if not done too frequentlyMethod to lower the maximum demand (pumping at non-peak hours)

  • * UNEP 2006Energy Efficiency Opportunities7. Impeller TrimmingElectrical Equipment/PumpsChanging diameter: change in velocityConsiderationsCannot be used with varying flowsNo trimming >25% of impeller sizeImpeller trimming same on all sidesChanging impeller is better option but more expensive and not always possible

  • *Pumps & Pumping Systems

    THANK YOUFOR YOUR ATTENTION

    *TO THE TRAINERThis PowerPoint presentation can be used to train people about the basics of pumps and pumping systems. The information on the slides is the minimum information that should be explained. The trainer notes for each slide provide more detailed information, but it is up to the trainer to decide if and how much of this information is presented also.

    Additional materials that can be used for the training session are available on www.energyefficiencyasia.org under Energy Equipment and include:Textbook chapter on this energy equipment that forms the basis of this PowerPoint presentation but has more detailed informationQuiz ten multiple choice questions that trainees can answer after the trai

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