外文翻译原文-超声波密封容器液位测量的仪器开发

DevelopmentofaUltrasonicInstrumentfortheSealedContainersLiquidLevelMeasurementLeiChen,XinminDongandJieHanPingYeInstituteofVibrationEngineeringCollegeofMechanicalandElectricalEngineeringZhengzhouUniversityChinaUniversityofMiningandTechnologyZhengzhou,Henan450002,ChinaXuzhou,Jiangsu221008,CAbstract-Ultrasonicisoneoftheeffectivemethodsinthefieldofliquidlevelmeasurement.Intheprocessofultrasonicpropagation,reflectionandrefractionwilloccurontheinterfaceofthetwodifferentmediums.Thereflectanceratiodependsontherelativeacousticimpedanceofthetwomediums.Thischaracteroftheultrasonicisusedinthemeasurementofthesealedcontainersliquidlevelandaninstrumentsystembasedonprogrammedsoftwareisdeveloped.Firstlythestructureandtheprincipleofworkofthesystemarepresented.Thenthetransmittingandreceivingcircuitisdesigned.Afterthatthesoftwareisdevelopedbythesecondarydevelopmentofthedataacquisitioncard.Andatlastthedevelopedinstrumentisappliedtotheliquidlevelmeasurementoftheair-conditioncompressorusedinthepassengertraincar.Thedevelopedinstrumentprovidesaneffectivemethodfortheliquidlevelmeasurementofthesealedcontainer.Andbecauseofitsmodularstructure,theinstrumentcanbeeasilytransplantedtootherrelativefields.IndexTerms-Ultrasonic,LiquidLevelMeasurement,TransmittingandReceivingCircuit,SecondaryDevelopmentINTRODUCTIONTheair-conditioncompressorusedinthepassengertraincarinChinaisusuallyasealedcontainer,anditsbreakdownmaybecausedbymechanicalfailureelectricalfailureorotherkindsoffailures.Butthefeedbacksfromthemaintenanceshopindicatethatmostofthebreakdownstookplacebecausetherefrigerantoilinthecontainerreducedtoalevelunderthedefiniteline1.Soitisimportanttokeeptheliquidlevelhighenoughtoensurethattheair-conditionrunproperly.Inthispaper,theultrasonictestingmethodisadoptedtoaccomplishtheliquidlevelmeasurement.InthetraditionalultrasonictestingsystemthediagnosisconclusionswereusuallydrawnbytheobservationoftheechowavedisplayedintheCRToftheflawdetector.Tomakefurtheranalysisoftheechowaveanddrawamoreaccurateconclusion,aninstrumentbasedonprogrammedsoftwareisdeveloped.Thesignaldatacanbenotonlydisplayedinthescreenofinstrument,butalsostoredforfurtheranalysistoenhancethereliabilityofthemeasurement.SYSTEMSTRUCTUREAsshowninfigure1,ThedevelopedinstrumentismainlycomposedofatransduceratransmittingandreceivingcircuitaDAQ(DAQ:DataAcquisition)cardandanotebookPC.Highvoltageelectricalpulsesproducedbythetransmittingcircuitareactedontheultrasonictransducertoexciteitemittingtheultrasonicwaves.TheechowavesaremagnifiedbythereceivingcircuitandacquiredbytheDAQcard.Andtheanalysisoftheseacquireddataarecarriedoutwiththedevelopedprogramsinthecomputer2.Theultrasonictransducerisareversibleelement.Itworksaccordingtothepiezoelectriceffect,whichincludespositiveeffectandconverseeffect34.ThetransmittingoftheultrasonicwaveactsinaccordancewiththeconverseeffectandthereceivingoftheechowaveactsinaccordancewiththeFig.1ThesystemstructureUltrasonictransducerTransmittingandReceivingCircuitDAQcardNotebookPCThisworkispartiallysupportedbytheOriginalityInnovationFoundforDistinguishedscholarsofHenanProvinceofChinaGrant#0621000500toJieHan.1-4244-0332-4/06/$20.002006IEEE4972Proceedingsofthe6thWorldCongressonIntelligentControlandAutomation,June21-23,2006,Dalian,Chinapositiveeffect.Figure2showstheprincipleofthepiezoelectriceffect.Ifitselectrodeisloadedwithelectricvoltage,thepiezocrystalwillvibrateinthedirectionofthicknessaccordingtothepositiveornegativeofthevoltage.Couplethisvibrationtotheworkpiece,theparticleofthematerialwillvibrateconsequently,andthusintheworkpiecetheultrasonicwavespreads.Thereceivingoftheechowaveisquiteanoppositeprocess.Theechowavebringsonthevibrationofthepiezocrystal.Thentheelectricalsignalgeneratedbythevibrationofthepiezocrystalisamplifiedandacquired.Theelectric-acoustictransformationisexcitedbythetransmittingcircuit.Intheprocessofultrasonicpropagation,reflectionandrefractionwilloccurontheinterfaceofthedifferentmediums.Thereflectanceratioisdeterminedbytherelativeacousticimpedanceofthetwomediums.Becauseoftheacousticimpedanceofthegas(Zgas=0.408h103kg/m2sec)ismuchdifferentwiththatoftheoil(Zoil=1288h103kg/m2sec),thereflectionacousticintensityofthesteel-gasinterfaceandthatofthesteel-liquidinterfacearemuchdifferent,especiallyaftermultiplereflection1.Sobyanalyzingoftheechowaves,theliquidlevelcanbedetermined.TRANSMITTINGANDRECEIVINGCIRCUITTriggeredbythecontrolimpulse,thetransmittingcircuitproduceslargescopenarrowpulsetoexcitethetransduceremittingtheultrasonicwave.Highvoltagethatthetransmittingcircuitneededischargedonalargevaluecapacitorandafieldeffecttransistor(IRF830).Figure3showstheworkingprincipleofthetransmittingcircuit.WhenG(Gate)isinhighlevel,D(Drain)andS(Source)willbeconnected,andthecapacitorwilldischarge.Sincethechargeinthecapacitycannotchangeabruptly,thehighvoltagenegativepulsewillbegenerated.Andthecrystalwillemitultrasonicwaveactuatedbythisnegativepulse.Afterbeingconvertedintoelectricalsignalbythepiezocrystal,theechowavewasputintothereceivingcircuit.Althoughitiseasytodesignwhenusingintegratedoperationalamplifierinthereceivingcircuit,theoutputisnotgoodbecausethesignaltobeamplifiedisfaintandhaswidefrequencyband.Sointhispaper,thediscretecomponent(diodetriode)isusedtorealizethefirsttwostageamplification.Afterthistwostageamplification,thesignalwasamplifiedelectrodeextendcontractFig.2Piezoelectriceffect(piezocrystal)Fig.4Schematicdiagramofthereceivingcircuit620ohmR2647uF/25VC133.8KR193.3KR1610-ohmR1727-ohmR1827KR15100-ohmR210.47uFC12IN4148D9IN4148D101.5KR2510-ohmR281KR231uFC111KR2023647185LF357NAR1C945Q5A733Q41KR240.01uFC1010uFC9+0.01uFC1510uFC14+10-ohmR27ToDAQCard510-ohmR22+IN4148D8IN4148D7L2L1T1T2FromTransducer+9-9Fig.3WorkingprincipleofthetransmittingcircuitHVpiezocrystal4973additionallybytheintegratedoperationalamplifierLF357N.Seenfromtheoutcomeofthetesting,thedevelopedreceivingcircuithasasteadyperformance,andtheamplificationreachesto60dB.Figure4showstheschematicdiagramofthereceivingcircuit.Sothehardwarestructureoftheinstrumenthasthefollowingcharacters:(1)Itisnotexpensivetobuild.ThehardwareismainlycomposedofatransduceratransmittingandreceivingcircuitaDAQcardandanotebookPC.TheanalogsignalisconvertedintodigitalsignalwiththeDAQcard,whichcommunicateswiththecomputerthroughparalleledport.(2)Thefieldworkscanbedonebytheinstrumentbecauseofitspowersupplymode.ThepowersupplyoftheDAQcardandthetransmittingandreceivingcircuitisprovidedbyaleadaccumulator.AndthenotebookPChasitsownrechargeablepowersupply.Sotheinstrumentcanworkatthecircumstancewithoutcommercialpower.(3)Thesystemcanbeintegratedintoaportableinstrument.Andmanyanalysescanbedonebythedevelopingsoftware.SECONDARYDEVELOPMENTOFTHEDAQCARDTheDAQcard,whichcommunicateswiththecomputerthroughtheEnhancedParallelPort,iscomposedofthemultiplexertheamplifierthesamplingandholdtheanalogtodigitalconverteretc.Thesoftwarefirstlyinitializestheportbaseaddress.ThebuffersintheDAQcardandthememorylinkthedataacquisitionandstorage5.ThedriveroftheDAQcardaccomplishesthecontrolandcommunicationbetweenandDAQcardandthecomputer.Figure5showsthestructureofthedataacquisition.ThemaintaskofthesecondarydevelopmentoftheDAQcardistodevelopanapplicationwithfriendlyuserinterface.TheDLLs(DynamicLinkLibrary)arecalledintheapplicationtodrivethehardwareofthecardandthedatainthememoryareacquiredanddisplayedonthescreenofthecomputer.Theapplication,whichisobtainedbythesecondarydevelopmentoftheDAQcard,canaccomplishdataacquisitionautomaticallyandhassomespecialanalysisfunctions.Whentesting,thedevelopedinstrumentcannotonlyacquirethesourcematerial,butalsomakereal-timeanalysisoftheechowaveandgiveaconclusionoftherelativepositionbetweenthetransducerandtheliquidlevel.Thusthemeasurementoftheliquidlevelismadeeasilyandautomatically.TheinstrumentsoftwareisdevelopedwithVisualBasic6.0andMeasurementStudio6.0.TheComponentWorksforVBoftheMeasurementStudio6.0softwarepackageprovidesActiveXcontrolsforuseintheVisualBasicdevelopmentenvironment.Thesecontrolsincludeinterfacecontrol,dataanalysisandsignalprocessingfunctions,I/Olibrariesfordataacquisitionandinstrumentcontroletc.TheuseofthesecontrolsextendsthedevelopmentenvironmentofVisualBasicandmakesiteasiertodevelopthesoftware.Figure6istheuserinterfaceofdataacquisitionsection.ThemainstepsofthesecondarydevelopmentoftheDAQcardwithVisualBasic6.0andMeasurementStudio6.0areasfollows:SignalExternaltriggerA/DBuffer(FIFO)DriverApplicationDisplayMemoryBufferHardwareDAQCardFig.5Structureofthedataacquisition49741.TocalltheDLLstodrivethehardwareintheVisualBasicandsettheglobalparametersandtheportbaseaddress;2.Todevelopthedataacquisitionprogramthatachievesthefunctionsofthedigitaloscilloscope.Thismodulecanstorethesignalanddisplayitonthescreenofthecomputer,besidesithassomefunctionsofdataprocessing.3.Toprogramthefunctionsofsignalanalysisandprocessing.Thesefunctionsareprogrammedbythedemandsandcananalyzethesignalsatreal-timeandafterwards.4.Todesignfilemanagementanddatamaintenancemodules.Thismodulesincludereportgenerationandprintingpartdatastoragepartandmeasurementrecorddatabase.5.Topackagethedevelopedprogramsintoamountingprocedure.Tosumup,thedevelopedsoftwareoftheinstrumenthasthefollowingadvantages:1)Itcanrealizethefunctionsofthedigitaloscilloscope;2)Ithasfriendlyuserinterfacesandcanbeeasilyoperated;3)Itcananalyzedataatreal-timeandtransducercompressorcontainervaporliquidFig.7Thecompressorandtheplacementofthetransducer(a)placementofthetransducer(b)theunpackedcompressorcontainerFig.6Dataacquisitionmodule4975Fig.8Ultrasonictransducerafterwardsandindicatetherelativepositionbetweenthetransducerandliquidlevel;3)ItcanstorethetestingdatainASCIIformatandgeneratethetestreportautomatically;4)Itismadeupofseveralseparatemodulesandcanbeeasilytransplantedtootherrelativefields.APPLICATIONOFTHEINSTRUMENTINTHELIQUIDLEVELMEASUREMENTDirectcontactmeasurementmethodisnotsuitablefortheliquidlevelmeasurementofthesealedconditioncompressor.Sothenoncontactmeasurementmethodusingultrasonicisadopted.Intheprocessofultrasonicpropagation,reflectionandrefractionwilloccurontheinterfaceofthetwodifferentmediums.Thereflectanceratiodependsontherelativeacousticimpedanceofthetwomediums.Theamplitudeofthemultiechoofthesteal-vaporinterfaceismuchhigherthanthatofthesteal-liquidinterface.Sowhenmovingthetransducerupanddown,theliquidlevelcanbefoundoutbyreal-timeanalyzingoftheechowave.Figure7(a)showstheplacementofthetransducer.Figure7(b)isanunpackedcompressorcontainer.Inordertoenhancetheprecisionofthemeasurement,theintersectedtransducerisadoptedasshowninfigure8.Itislinefocusing;thefocallengthis5mm,whichisthesameasthewallthicknessofthecontainer.Thetypeofthetransduceris1.25P12F5.Thetransducerisfixedinashifter,whichcanmoveupanddownalongthewallofcontainer.Thesurveyorsstafffixedonthetransducerindicatesitsheight;simultaneitytheinstrumentanalyzestheacquiredsignalatreal-timeandindicatesthepositionbetweenthetransducerandtheliquidlevel.Inthiswaythemeasurementisaccomplished.Figure9showstheechowavesbelowanduppertheliquidlevel.CONCLUSIONInallusiontotheliquidlevelmeasurementoftheairconditioncompressorssealedcontainer,afeasibletestmetho