Understanding Ultrasonic Level Measurement · for general background information. They are too numerous to mention, but their enthusiasm for the technology and their efforts are much

Understanding

Ultrasonic Level

Measurement

third edition SIEMENS

Ives Equipment | 877-768-1600 | www.ivesequipment.com

http://www.ivesequipment.com

AcknowledgementsAsyoucanimagine,aprojectlikethisinvolvestheeffortsandcontributionsofmanypeople.Tobeginwith,theauthorswanttothankthegenerationsofengineers,designers,applicationspecialists,salespeople,supportstaff,andmanagementwhohavedevelopedthetechnologyandtheproductsovertheyears.Allofusalsooweahugedebtofgratitudetoourcustomerswhohaveallowedustogrowandtoshareintheirsuccessesbyparticipatinginourvision.Alltogether,theyhavecreatedtheSITRANSLUT400,therevolutionaryultrasoniccontrollerwithonemillimeteraccuracythemarketshavebeenwaitingfor.

Theauthorsalsowanttothankallofthewritersandphotographerswhohavecontributedmaterialusedinthisbook,bothinspecificcontentandforgeneralbackgroundinformation.Theyaretoonumeroustomention,buttheirenthusiasmforthetechnologyandtheireffortsaremuchvalued.TheartisticcontributionsofPeterFroggattarealsoappreciated.Overtheyears,hisdrawingsandphotoshavehelpeddefinetheproductline,andhisworkgracesmanyofthepagesinthishumbletome.Thosewhotookthetimetoeditandprovidecommentsandotherinputalsohaveourgratitude.

Specifically,wewanttothanktheeditingandorganizationalskillsofJamieChepeka.Herdedicationtotheprojectwasunwavering,eveninthefaceofloomingdeadlinesandcreativeangst.Withouthermanagementguidance,wewouldstillbestaringatourscreens.

Lastly,theauthorsapologizeinadvanceforanyandallmistakes,inaccuracies,andomissions.Wetakefullresponsibilityandassureyouthatwewilldobetternexttime.



Contents

ChapterOneHistoryofultrasonicsUltrasonicsandlevelmeasurementProductdevelopmentmapUltrasonictheorySoundUsingsoundFrequencyandwavelengthMeasurementprincipleThemediumandthemessageSoundintensitySoundvelocityandtemperatureSoundvelocityandgasSoundvelocityandpressureSoundvelocityandvacuumSoundvelocityandattenuationSoundreflectionSounddiffractionSoundpressurelevel(SPL)Soundintensitychanges

Summary

ChapterTwoUltrasonicinstrumentationThetransducerTransducerenvironmentsTransduceraccuracyTransducerresolutionandaccuracyImpedancematchingAxisoftransmissionBeamwidthBeamspreadingRingdownThecontrollersDigitalfilteringAveragingechoesEchoextractionalgorithms

Summary



ChapterThreeThesoundandtheslurryTopicsTransducersandultrasonicsystemsSinglesystemsCompoundsystems

TransducersTemperatureandtransducermaterialTemperaturesensors

SoundanddifferentialamplifiersSingle-endedreceiverDifferentialreceiverApplicationtemperatureHousingmaterialRangeandpowerConditionsTransducerselectionBlankingdistanceandheightplacementTemperatureInstallationTransducerdesign:theheartofthematter

Summary

ChapterFourEchoprocessingTopicsEchoprocessing-intelligenceUnderstandingechoprocessingShotsandprofilesFindingthetrueechoEchoqualityFigureofmeritEchoparameterfinetuningEchoprofilesProfilecomponentsEchoprofileRingdownTVTcurve(TimeVaryingThreshold)EchomarkerEcholockwindowEchoprocessingparametersEchoconfidenceTheechoEchostrength



NoiseNoiseinterferenceDeterminingthenoisesource

Non-transducernoisesourcesCommonwiringproblemsReducingelectricalnoiseAcousticnoiseReducingacousticnoise

Summary

ChapterFiveInstallationTopicsSelecttherighttransducerLocationObstructionsClosedvesselsTanksTankaccessOpenvesselsOpenchannelmeters:weirsandflumesFlumesTransducerlocationLiftstationsPositioncontrolHazardousapprovalsApprovalsControllerinstallation

Summary

ChapterSixApplicationsApplicationsTopicsCementMiningChemicalstorageAggregateBlendingsilosandstoragebunkers

EnvironmentalCollectionsystem:liftstation/pumpstation/wetwellWastewatertreatmentplantEnvironmentalapplicationsFoodindustryChemicalindustry



Otherindustries

ChapterSevenBestinclass–theultrasonicproductlineSITRANSLUT400Keybenefits

SITRANSProbeLUKeybenefits

TheProbeKeybenefits

MultiRanger100/200Keybenefits

SITRANSLU10Keybenefits

HydroRanger200Keybenefits

EchomaxTransducersXRS-5Keybenefits

XPS/XCTSeriesKeybenefits

XLTSeriesKeybenefits

ST-HKeybenefits

Conclusion

GlossaryWorksCited



ChapterOne

HistoryofultrasonicsHowsweetthatjoyoussound,wheneverwemeet.1

SiemensMilltronicsProcessInstrumentshasalongandsuccessfulhistoryspecializinginthemanufactureofequipmentforindustrialprocessmeasurement.BasedinPeterborough,Canada,SiemensMilltronics(PI2)isnowakeymemberoftheSensorsandCommunicationdivisionwithintheSiemensIndustrydivision,supplyinginstrumentationacrosstheglobe.

Foundedin1954byStuartDaniel,aformeremployeeofCanadianGeneralElectric,thecompanybeganasMilltronicsandengineeredelectronicballmillgrindingcontrolsforthecementandminingindustry.Fromthis,thecompanyexpandedanddiversifieditsproductlinetodevelopawiderangeofprocessmeasurementdevices.Ithasbecomealeaderinlevelmeasurementtechnology.TheSiemensMilltronicsrangeofinstrumentationnowincludesultrasonic,radar,andcapacitancetechnologies,butthefoundationofitsinnovationandsuccessfuldesignandtechnicalexpertiseliesinitsultrasonicecho-rangingtechnology.

SiemensMilltronicsultrasonicecho-rangingtechnologycompriseshighlysophisticatedinstrumentationapplyingdigitalcircuitrytoultrasonicecho-ranging.Thisinnovationhasproducedarangeoftechnologicallyadvancedproductscapableofmonitoringliquidandsolidslevelsfromafewcentimeterstoover60meters(200ft).Todate,over1,000,000pointsoflevelonadiverserangeofmaterial,includingsolids,liquids,slurries,andresins,aremonitoredacrosstheglobebySiemensMilltronics,manyinhostileandhazardousenvironments.

TheSiemensMilltronicsultrasonicproductlineisconstantlyimprovingastechnologicaladvancesareimplemented,newproductsaredeveloped,andnewapplicationsaretackledandwonover.Complementedbyateamofhighlyskilledapplicationsengineers,servicepersonnel,andadedicatedSiemenssalesforce,SiemensMilltronicscontinuestoprovide



reliableandinnovativelevelsolutionstoindustryacrosstheglobe.

UltrasonicsandlevelmeasurementThemeasurementoflevelhasbeenintegraltohumandevelopmentsincepre-industrialtimes.

“Egypt,”Herodotusremarkedmorethan2000yearsago,referringtothevastirrigationprojectthatsustainsthatcountry’sagriculture,“isthegiftoftheriver.”EveryJune,assnowmeltsfromtheTanzanianHighlandsandspringrainfromtheCongobeginaccumulatingintheNile,itselevationbeginstorise.ItrisesgentlytoacrestinlateSeptemberorearlyOctober,thensubsidesbylateDecember.Seedgoesintotherich,freshlydepositedsiltassoonasthefloodrecedes.

Egyptianengineersbegancapturingtheriverforirrigationprojectsabout7,000yearsago.Becausethesystemreliesonacomplicatedsystemofgatestodistributewateracrossabroad,relativelyflatarea,it’svitalthatengineersknowtheheightoftheriverinadvanceofitsarrival.Thefirstsolutionwastosimplymarktheriverbanksandconveyinformationbacktoheadquartersviarunners.Later,engineersdevelopedalargevarietyof“nilometers,”devicesusedto



measuretheriverheight.Most,however,consistedofordinarygraduatedscalesthatprojectedverticallyupwardfromtheriverbedandwerereaddirectly.

Today,theU.S.GeologicalSurveyandtheNationalOceanicandAtmosphericAdministrationusesimilardevices:graduatedpolesstuckintothewater.Techniciansreadmostofthemmanually,buttherearesomeinflood-proneareasthattransmitinformationdirectlytotheagencyviaradio.Thoughmillennia-oldsolutionsformeasuringriverlevelarestillinuse,therearethousandsoflevel-determinationproblemsinindustrythatdemandmuchmoresophisticatedsolutions.Liketheirforebears,contemporaryengineershaverespondedwithimpressiveingenuity.2

IngenuityisalsothekeytothesuccessofSiemensMilltronicsultrasonictechnologyasitmeetsthedemandsoflevelmeasurementintheprocesssystemsmarket.TheneedforprocessmeasurementdatesbacktotheIndustrialRevolutionwhenthedevelopmentofthesteamenginecreatedarequirementfortheaccuratemeasurementoftemperature,pressure,andflow.

Bytheearlytwentiethcentury,processengineersweredeterminingprocessmeasurementsusingavarietyofmechanicaldevicesincludingfloats,sightglasses,thermometers,gauges,andarmatures.Accuracywasoftenelusive,andthesedevicesweresupplementedbyhumanexperience.Processengineersoftenreliedontheirsensestocomplementthetechnology:usingsight,sound,touch,smell,andeventexture,engineerswouldexamineprocesssmoke,liquidclarity,texture,andsmelltodetermineproductquality.However,chemicalcompounds,safetyrestrictions,systemcomplexity,andawarenessnowmakethistypeoftactileverificationimpossible,requiringmeasurementtobemadebytheinstrumentalone.

Processmeasurementincorporatesavarietyofsolutions,frompressureandtemperaturetoflowandlevel.WhileSiemensSCPIoffersinstrumentationtomeasureallofthese,SiemensMilltronicsspecializesinthecalculationoflevel.



Levelmeasurementinstrumentationcurrentlyemploysavarietyofsophisticatedtechnologies,withultrasonicmeasurementasthecornerstone.Theoriginsofultrasonicmeasurementtechnologylieinearlyusebysubmarinesofsonarfordepthgaugingandmarinedetection,butitwasn’tuntil1949thattheseprincipleswereappliedtolevelmeasurement.BobRedding,ofEvershedandVignoles,developedanultrasonicinstrumentwithservocontrolthatautomaticallymeasuredoillevelandthentransferredthatinformationtoaremoteindicator.

OthertechnologieswerealsoappliedtoremotelevelmeasurementbycompanieslikeMagnetrol,whichapplieditsmagneticswitchingtechnologytothecontrolofpumpsandotherdevicesforuseinwaterlevelalarming.Thedevicetransmittedlevelchangestotheswitchmechanismwithoutanymechanicalorelectricalconnectionandeliminatedmechanicaldevicessuchasdiaphragmsandstuffingboxes.

In1963,MagnetrolintroducedModulevel©3,thefirstmagneticallycoupledpneumaticproportionallevelcontrol.Thefirstsignificantsensinginstrument,itledthewaytonewmarketsincontinuousprocesslevelcontrol.Bythe1970s,ultrasonictechnology,alreadyusedinshipandplanedetection,wasdevelopedforthemeasurementindustries.Sonarprincipleswereappliedtouseinair,usingmodifiedlowfrequencysonarequipmentwithpiezoelectriccrystalstogenerateechoranging.Thesenewsensorswereappliedtoprocesscontroltaskssuchaspointlevel,continuouslevel,concentration,andfullpipeapplications.Inthemid-1980s,analoginstrumentationwentdigitalandoffered4to20mAsignal,openingupcommunicationpossibilities,andgreatlyincreasingitsvalueascontrolinstrumentation.

Milltronicsenteredthemarketintheseearlydaysofultrasonicdevelopment.In1973,afterbeingthemainRaytheon®4distributorinCanadaandtheUSA,MilltronicsacquiredtheRaytheonUltrasonicRangingbusinesssegmentandtheAiRangerIIproduct.Overthenext30years,Milltronics®5hasbecomethemarketleaderandthemosttrustednameinultrasonicslevelmeasurement.AftertheSiemensacquisitionin



2000,theMilltronicsbrandhascombinedwiththeTotallyIntegratedAutomationvisionofSiemenstoofferultrasoniclevelmeasurementequipmentasanintegralcomponentofcompletesystemdesign.

Productdevelopmentmap

Ultrasonictheory



Ultrasonicmeasuringtechnologyoperatesonthesimpleprincipleofmeasuringthetimeittakessoundtotraveladistance.Whiletheideaissimple,theprocessofcreating,controlling,andmeasuringthesoundtravelisnot.

SoundSoundistheinterpretationofelectricalsignals.Thesesignalsarederivedfromacousticpressurewavesthatactivateatransducersimilartothehumanear.Thisorganictransducerinterpretstheelectricalsignalschanneledintotheearcanal.

Thesoundsignalsarecausedbythemechanicalvibrationoftheobject.Thevibrationistransferredtothegasmodulesinthesurroundingmediumwithinwhichitiscontained.Thetransferoccursasthevibrationsalternatelycompressanddecompressthemoleculesnexttotheobject,spreadingoutwardliketheringsinapondintowhichastonehasbeenthrown.Astheobjectmovesintothegas,itsmoleculescompressintoasmallerspace.

Astheobjectmovesoutofthegas,itsmoleculesdecompressintoalargerspace.Thispatternorwaveofcompressionanddecompressiontravelsoutwardfromthevibratingobjectthroughthegasandmanifeststhephenomenoncalled“sound.”Ifthereisnogas,asinaperfectvacuum,thentherewillbenopropagationofsound.



Soundlevelsintheeverydayworld

Thesound,ornoise,ofeverydaylifesurroundsusfromourbreakfasttohouseholdchores,work,andtravel.Soundiseverywhereanditsoccurrenceseemsanaturalpartofourenvironment.Sound,however,canalsobeused,notjustfordirectcommunicationasinspeechormusic,butalsoasaresourcetobeharnessedandthenappliedtoamethodofmeasurement.

UsingsoundSoundcanbeusedasameasurementtoolbecausethereisameasurabletimelapsebetweensoundgenerationandthe“hearing”ofthesound.Thistimelapseisthenconvertedintousableinformation.Ultrasonicsensingequipmenthastheabilitytogenerateasoundandthenthecapacitytointerpretthetimelapseofthereturnedecho.Itusesatransducertocreatethesoundandsensetheecho,andthenaprocessortointerpretthesoundandconvertitintoinformation.



Frequencyandwavelength



Vibrationofthesoundwavesisrelatedtotimeandiscalled“frequency.”FrequencyismeasuredinHertz(Hz)andreferstothenumberofcyclespersecond.Apuresoundwaveofaparticularfrequencyexertssoundpressurewhichvariessinusoidallywithtime.Onewavelengthorcycleisdefinedasthedistancefromonecompressionpeaktothenext.Thewavelengthofaspecificfrequencyisrelatedtothevelocityatwhichthesoundtravels:

ThenumberofcyclesthatoccurinoneseconddefinesthefrequencyinHertzatwhichthesoundisbeinggenerated.Forourpurpose,thefrequencyisconstant.Atbest,thehumanearcandetectsoundsrangingfrom20to20,000Hertz.Thesoundrangeabovethisfrequencyisknownasultrasonics.

MeasurementprincipleApiezoelectriccrystalinsidethetransducerconvertsanelectricalsignalintosoundenergy,firingaburstofsoundintotheairwhereittravelstothetarget,afterwhichitisreflectedbacktothetransducer.Thetransducerthenactsasareceivingdeviceandconvertsthesonicenergybackintoanelectricalsignal.Anelectronicsignalprocessoranalyzesthereturnechoandcalculatesthedistancebetweenthetransducerandthetarget.Thetimelapsebetweenfiringthesoundburstandreceivingthereturnechoisdirectlyproportionaltothedistancebetweenthetransducerandthematerialinthevessel.Thisverybasicprincipleliesatthemeasurementheartofthetechnologyandisillustratedinthisequation:



Thespeedofsoundthroughairisaconstant:344meterspersecondwithinanambientairtemperatureof20°C.Therefore,ifittakes58.2millisecondsfortheechotobedetected,wehavethisresult:

ThemediumandthemessageForanultrasonicmeasuringsystemtohaveanyvalue,itmustprovideaconsistentoutputvalueforthesamephysicallevelconditionsoveralongperiodoftime.Thisrepeatabilitydependsmostlyonconditionsofthesoundmediaandthetargetmaterial.Thevelocityofsound(344m/sec)isdeterminedthroughthestandardmediumofairandattheidealtemperatureof20°C.However,oftentheconditionsunderwhichultrasonicmeasurementoccurarenotidealastherecanbenumerousfactorsinfluencingthemedium,therebyalteringthesoundtransmissionspeedandaffectingmeasurement:

temperaturemediumtype(gas)mediumstratificationvacuum

SoundintensitySoundintensitydescribeshowmuchenergythereisinawaveofsound.Theunitsofsoundintensityarewattspersquaremeter(W/m2).Whensoundintensitiesarecomparedtooneanother,itisusualtousethedecibelasaunitofmeasure.TheratiooftwosoundintensitiesI1,andI2isgivenbythisequation:



Forsoundinair,theusualreferenceintensitychosenasthe0dBpointis0dB=10-12W/m2.Usingthatreferencepoint,120dBdescribesasoundintensitythatis120dBlargerthanthe0dBreferenceintensity,whichisanintensityof1W/m2.120dBisconsideredthethresholdofpainforthehumanear.Thedecibelscaleisusedbecauseofitsabilitytoeasilycomparesoundintensitieswhichmayvaryoveranenormousrangeofvalues.

SoundvelocityandtemperatureTemperaturechangesaffectthevelocityofsoundinair,andthevariationsintemperaturerequirecompensationtocalculateaccuratemeasurement.Ifthetemperatureoftheairbetweenthetransducerandthetargetisuniform,thencompensationisachievedandanaccuratemeasurementcanbemade.

Thetemperatureoftheapplication,orthemediumthroughwhichthesoundtravels,isrequiredtocalculatethevelocity.However,SiemensMilltronicstransducershavebuilt-intemperaturesensors,andatemperaturereadingistakeneachtimethetransducerisfiredtocompensatefortemperaturefluctuations.



Thischarttrackstheincreaseinthevelocityofsoundasthetemperatureincreases.

SoundvelocityandgasThevelocityatwhichsoundpropagatesinagasisconstant,aslongastherearenochangesinthegas.Thefollowingformulacalculatesthevelocityforagas:

Example

At(20Celsiusor293Kelvin),thevelocityofsoundis:



Notethatthespeedofsoundvarieswithabsolutetemperature.Inairatnormalambienttemperatures,whichisabout300K,achangeof1KorC(to301K)causesthespeedofsoundtoincrease:

SoundvelocityandpressureSoundvelocityinamediumexperiencingvariablepressuresiscalculatedusingthefollowingformula:

Thisformulasuggeststhatthespeedofsoundvarieswithpressureasitdoeswithtemperature.

Thevaporsaturationinairofvariouschemicalsmustalsobeaccountedfor.Thesaturationlevelisrelevanttothedifferentvaporpressuresofeachchemicalasillustratedinthenextchart.Notethatthecurvedlinesarefor100%saturationandthetruesoundvelocityisinbetweentheapplicablecurveandthatshownforair.



SoundvelocityandvacuumIfatreefallsinavacuum,doesitmakeanynoise?No.Soundrequiressomethingtovibrate,andinavacuum,thereisnomediumtovibrate.Thusanapplicationthatoperatesinavacuumhastorelyonanalternatetechnologyforlevelmeasurement.

SiemensMilltronicshasacomprehensivelineofradarinstrumentsfornon-contactingmeasurement,andathoroughrangeofcapacitanceinstrumentsandguidedwaveradarforlevelandinterfacecontactmeasurement.Allthesetechnologiesoperateperfectlywellinavacuum.

SoundvelocityandattenuationAttenuationreferstoadecreaseofsignalstrengthasitmovesfromonepointtoanother.Forsoundsignals,ahighdegreeofattenuationgenerallyoccurswheretherearehighlevelsofdust,humidity,orsteam.Attenuationalsooccurswheretargetmaterialsarehighlyabsorbentto



sound,foamforexample.Insuchapplications,impedanceandfrequencyselectionareessentialinordertotransferasmuchpoweraspossiblefromthetransducerintotheairandviceversa.

Wherethemediumbetweenthetransducerandthetargetisotherthanthenaturalcompositionofair,thevelocityofsoundcanalsochange.Ifthemediumishomogeneous,compensationcanbeachieved.If,however,themediumisstratifiedsothepropagationofsoundundergoeschangesinvelocityatvariouslevels,thenonlyanapproximationcanbemadebyusingtheaveragevelocityofthemediumtocalculatethedistancethatthesoundhastraveled.

SoundreflectionWhenasoundwavearrivesataninterfacebetweenmediaofdifferentdensity(e.g.airandwater),someofthesoundenergyisreflectedandsomeofitistransmittedthroughthesecondmedium.Theratioofenergyreflectedtoenergytransmittedisdependentupontheacousticimpedancesofeachmedia.Thegreatertheratioordifference,thegreatertheamountofenergythatwillbereflected.



Theangleofthereflectedsoundwave(onasmoothsurface)isequaltotheangleoftheincidentsoundwave,buttotheoppositesideofthenormaltotheplaneofthesurface.Ideally,formeasuringlevel,thisangleiskepttoaminimum.

Asurfaceisconsideredsmoothiftheroughness,expressedasthepeaktovalleydifference,is1/8orlessoftheincidentwavelength.Anyabsorptionofthesonicenergyisignoredforthisexample.

SounddiffractionDiffractionoccurswhenthesoundwavebendsaroundanobjectsuchthatthereislittleornoreflection.Foragivensizeobject,diffractiondecreaseswithadecreaseinwavelength(increaseinfrequency).

Soundpressurelevel(SPL)Soundpressurelevel(SPL)isthepressureofsoundincomparisonwiththereferencepressurelevelwherePrefisthereferenceforsoundpressureinair(20.4mPaat1KHz).TheSPLcanbemeasuredbyamicrophone.

SoundintensitychangesWhensoundpropagateswithinagas,itspreadsoutsothattheenergyitcarriesisdiffusedoveranincreasingareaasthewavetravelsfurtherfromitssource.Excludinglossescausedbyotherfactorsdescribedlater,soundintensitydecreasesataratethatisinverselyproportionaltothesquareofthechangeindistance.



Thatistosay,iftheintensityofsoundisXatapointlfromthesource,thentheintensitywillbeX/4atadistanceof2lfromthesource.

SummaryThesoundwavesareaffectedbymanyfactorswithintheapplicationenvironment,andtheapplicationengineermustalwaysverifythatalltheseconditionsareknownbeforesettinguptheapplication:

temperaturemediumabsorbency(dust,steam)mediumtypepressuremediumstratificationvacuumreflectivityofmaterial

SiemensMilltronicsultrasonicinstrumentationtacklesapplicationsthatinvolveoneormoreoftheseconditions.Ourexperiencedsalesapplicationengineerswilldesignaninstrumentconfigurationthatwillprovidereliableandaccuratemeasurement.

1VanMorrison,“JoyousSound.”APeriodofTransition,1977.2Felton,Bob.“LevelMeasurement:AncientChore,ModernTools.”ISA,August2001.3ModulevelisaregisteredtrademarkofMagnetrol.4®RaytheonisaregisteredtrademarkoftheRaytheoncompany.5®MilltronicsisaregisteredtrademarkofSiemensMilltronicsProcessInstruments.



ChapterTwo

UltrasonicinstrumentationStop,children,what’sthatsound1

Measurementrepeatabilityisdependentonthesignalprocessorbeingused.Thespecifiedaccuracyvaluestakeintoaccountsuchfactorsaslossofresolution,supplyvoltagevariation,operatingtemperature,circuitlinearity,andloadresistance.Thesefactorsdependontheinstrumentationhardwareandsoftware,nottheapplicationconditions.

Ultrasoniclevelmeasurementinstrumentationrequirestwocomponents,onetogeneratethesoundandreceivetheecho(transducer),andonetointerpretthedata,deriveameasurement,andaffectareactionofthecontroller.Eventhoughsomeultrasonicinstrumentscombinethecomponentsinoneunit(SITRANSProbeLU,PointekULS200),theindividualfunctionalityremainsdistinct.Theoperationandtechnicalspecificationsregardinginstrumentperformancewillbediscussedindetailinsubsequentchapters.

ThetransducerAdvancesinthedesignofultrasonictransducershavesignificantlycontributedtothesuccessofultrasonicsasalevelmeasurementtechnology.Transducersarethevocalchordsandearsofanultrasoniclevelmeasurementsystem.Thesoundpulseiscreatedbythetransducerwhichconvertstheelectricaltransmitpulseintosonicenergy,effectivelyradiatingthatsonicenergyintotheairandtowardsatarget.



Afterthetransmissionprocessiscomplete,thetransducerthenactsasthereceivingdeviceforthereturningechosignal.Thisinformationisthenprocessedandturnedintoameasurementvalue.

Theeffectiveacousticenergyisgeneratedfromthefaceofthetransducerandisradiatedoutward,decreasinginamplitudeatarateinverselyproportionaltothesquareofthedistanceastheunitenergyisdissipatedoveralargerarea.Maximumpowerisradiatedaxially(perpendicular)tothefaceinalinereferredtoasthe“axisoftransmission.”Whereoff-axispowerisreducedbyhalf(-3dB)withrespecttoanon-axispointequidistantfromthetransducer,aconicalboundaryisestablished.Thediametricalmeasurementoftheconeindegreesdefinesthehalf-powerbeamangle.Althoughthebeamangleforaroundfacetransducercanbederivedempirically,itcanbepredictedbythefollowingformula:

TransducerenvironmentsTransducerscarryafullrangeofhazardousapplicationapprovalsfromCSAandFMtoATEX(EuropeanUnionExplosiveAtmospheresprotection).Constructedfromthemostadvancedmaterialcompounds,transducersareavailableforsomeoftheharshestindustrialenvironments:

Forcorrosiveapplications,transducersarefabricatedwithmaterialssuchasPVDForPTFE,allowingultrasonicstobeusedwithacidsandsolvents.Industyapplications,acousticimpedancematchingmaterialssuchaspolyurethaneandpolyethylenefoamareusedbecausetheirelasticpropertiesamplifythecrystal’svibration.



Forlong-rangesolidsapplications,long-rangetransducersdeliverhighpoweroutputtomeasuresolidmaterialsaccuratelytodistancesover200feet.Theflexuralmodetransducerdeliversmorepowerbydrivingalargecentraldiscwiththecentralpiezoelectriccrystal.Thelargemetaldiscismadetovibratealongwiththepiezoelectriccrystal,producingastandingwaveonitssurface.Holespunchedinconcentricringsalloweveryotherantinodetobedelayedtothepointthattheybecomeinphasewiththeothers.Theneteffectisanintensesoundpressurewavewhichistransmittedintotheair.Thistypeoftransducerisverywellsuitedfordustyenvironments.

TransduceraccuracyTheaccuracyofanyinstallationisdependentonthecaretakentoensuretheelectronicsagreewiththephysicalmeasurementandtheaccuracyofthiscalibration.Duetothedesignoftheelectronics,insitucalibrationiseasyandhighaccuracyisreadilyobtainable.Traceabilitytoknownstandardsisdependentonthemethodandequipmentusedasthereference.

TransducerresolutionandaccuracyTheminimumchangeorincrementofdistancethatcanbedetectedisreferredtoastheresolutionofthemeasurementsystem.Resolutionisdependentonthewavelengthandthetimingresolutionoftheelectronics.Theshorterthewavelength,thesmallertheincrementthatcanberesolvedgivenaspecificsignalprocessor.TheSITRANSLUT400,hasadesignresolutionoflessthanonemillimeter(0.078")andaonemillimeteraccuracyspecification.

Inscience,engineering,industryandstatistics,accuracyisdefinedashowclosethemeasurementsystemquantityistothemeasurementofthatquantity’sactualvalue.

Impedancematching



Thevibrationofthetransducerfaceactsuponthesurroundingairtoproduceasoundwave.However,forefficienttransferofpowerfromthecrystaltotheair,impedancematchingmaterialsmustbeused.Matchingmaterialstepsdownthehighimpedanceofthecrystaltothelowimpedanceofair.OnSiemensMilltronicstransducers,aspeciallowdensitymaterialisusedasaninterface.

Theimpedancematchingcanbefurtherenhancedbyanadditionalfacingmaterial.However,thisisnotalwaysrequirednorpracticalfromanapplicationstandpoint.

Acousticimpedancematchingisimprovedbythesematerialsastheirelasticpropertiesamplifymagnitude(D)ofthecrystal’svibration.Asexpressedbythisformula:

Moreamplitudeisnowpossiblewithagivenforcebyincreasingthedistancethevibrationhastraveledthroughthetransducerface.

AxisoftransmissionSoundenergyisgeneratedfromthefaceofthetransducerandradiatesoutward.



Theenergygeneratedatthefaceofthetransducerdecreasesinamplitudeatarateinverselyproportionaltothesquareofthedistancetraveled.Maximumpowerisradiatedaxially(perpendicular)tothefaceinalinereferredtoasthe“axisoftransmission.”

BeamwidthBeamwidthisdefinedas“twicetheangleatwhichoff-axistransmissionis3dBlessthanthetransmissionaxisacousticpressurelevels(asmeasuredequidistantfromthetransducerface).”Therefore,adiametricalpowermeasurementoftheconeindegreesdefinesthehalf-powerbeamangle.



Beamwidthisafunctionofthetransducerradiatingsurfacearea,frequency,andplane.

Forultrasoniclevelmeasurement,widedispersionisundesirable.Thenarrowerthebeamwidth,thelesslikelyvesselobstructionswillbedetected.

Forshortandwidevessels,a12°beamwidthisidealtosimplifyaiming.Fortall,narrowvessels,a5°to6°beamwidthwillavoidvesselwallseamorcorrugationdetectionformaximumreliability.

BeamspreadingAswellasthemainbeam,sidelobesofamuchlowerintensitymayradiateintheformofaconicalshell,concentrictothemaincomponent.Themaincomponentandthesidelobesmaybedepictedonapolarplotinordertovisualizethepatternofsound.Itisdesirabletohaveasmuchenergyaspossibleconcentratedinthemainbeaminordertoreduceunwantedechoesgeneratedfromthesidelobes.Similarly,itisnecessarythatenergybepreventedfromradiatingfromtheendoppositethetransducerface.Aswellasgoodoutputpower,thetransducermustbesensitivetotheweakreturnechoesasnoamountofelectronicscan



compensatefornon-detectionofanecho.Thus,propertransducerdesignisfundamentallyimportantinputtingthetheoryofultrasonicechorangingintopractice.

RingdownTheprimaryactivecomponentofthetransducerisapiezoelectriccrystalthatexhibitsanexpansionandcontractionofitslengthwhensubjectedtoalternatingvoltage.Whenthevoltageisremoved,thecrystalisnolongerexcitedanditsmechanicalvibrationbeginstodecay.Theinherentnatureofthecrystalandthesurroundingtransducermassistocontinuevibrating.Thisvibrationiscalled“ringing.”Thetimeittakesforthisringtostopisoftencalled“ringdown.”

Thelevelofringingdependsnotonlyonthecrystalitselfbutalsoonthematerialsandconstructionoftheentiretransducer.Moderntransducershavesignificantlylessringdownthanearlierversions.Duetoresearchintothelatestconstructionmaterialsandtechniques,theblankingdistanceofthenewestultrasonicinstrumentsliketheSITRANSProbeLUisnowonly0.25meters(10").

Thecontrollers



Thetransducerscanbelikenedtothescoutsofalevelmeasurementsystem.Theygooutandgettheinformationandbringitback.Thecontrollersanalyzethatinformationandthenturnitintosomethinguseful.

Sinceitsinception,ultrasoniclevelmeasurementtechnologyhasimprovedgreatlywithadvancesinelectronicsignalprocessors.Digitalsystemstransmitinthesamemannerasanalogsystems,butdigitizetheanalogreceivedsignalofthereturnechoandstorethecompleteechoasaprofile.

Theprocessor,insidethecontroller,thenanalyzestheprofileusingsoftwarealgorithms,extractingoneechofromtheprofileasthemostprobabletobethetargetecho.Then,thesignalprocessorconvertsthetimedifferentialbetweenthetransmitandthetimeoftheselectedtargetechointodistance.

Digitalultrasonicmeasurementalsohastheabilitytousesoftwarefilteringtechniquesandintelligentechoextractionalgorithmstodeterminedistance.Themicroprocessorgivesthesignalprocessortheabilitytoperformhighspeedmanipulationofthedatagatheredfromanechoprofile.Usinganalog-to-digitalconversion,echoprofilesreceivedbythetransduceraredigitizedbythereceivingdeviceandstoredinmemoryforfutureevaluation.Storingtheechoprofileinmemorymakesitpossibletoperformthemanytestsonthedatanecessarytodeterminethetruematerialecho.



DigitalfilteringDigitalfilteringremovesunwantednoisefromtheechoprofile,includingelectricalnoisealwayspresentinanindustrialenvironment.

Forexample,variablespeedmotordrivesproducehighlevelsofelectricalnoisethatareusuallyveryhighinamplitudeyetveryshortindurationwhencomparedtothedatabeinggatheredfortheechoprofile.Therefore,digitalfilteringisusedtoremoveanydatafromtheprofilebelowagivenlimitinduration,significantlyreducingtheeffectofthenoiseontheoverallmeasurementquality.

AveragingechoesInapplicationsthatcreatehighlevelsofdustoracousticnoise,highspeeddatamanipulationpermitstheaveragingofmanyechoprofilestodevelopacompositethatcanbemoreaccuratelyanalyzed.Averagingofechoprofilesperformsseveralusefultasks:randomsourcesofinterferencesuchasacousticnoiseoraircurrentsareaveragedoutoftheechodataandechoesareenhancedindustyandotherwisechallengingapplications.

EchoextractionalgorithmsEchoextractionalgorithmsaresoftware-basedfunctionsusedtoevaluateanechoprofile.Anechoprofilecanbeevaluatedinmanyways,witheachmethodhavingparticularadvantagesindifferentapplications.Beforemicroprocessors,analogsignalprocessorsevaluatedtheechoprofileasitreturnedandthenthereceiverlookedforanyechoaboveasetthreshold.Onceanechoofsufficientamplitudewasdetected,thedistancewascalculatedandtheoutputwasgenerated.Unfortunately,analogsignalprocessorswereunabletodifferentiatebetweenrealbuterroneousreturnsandthetrueechoindifficultapplications.

Digitalsignalprocessorsapplyechoextractionalgorithmsaftertheentireechoprofilehasbeenreceived,andthenusemanytechniquestodeterminewhichechorepresentsthetruemateriallevel.



Onemethodofechoextractioninvolvesstoringaprofileoftheemptybin.Thisstoredprofileisthenusedasatemplate,allowingtheprocessortoignoreobstructionsinthebin.Forexample,inabinfabricatedwithbracingaroundtheinsidesurface,thereturnechoescanindicatebracingandnotlevel.Whentheechoprofilefortheemptybiniscaptured,theprofileshowsechoreturnsindicatingthebracings.Inordertodiscriminateagainsttheseerroneousechoes,thesignalprocessorcompareseachechoprofiletothetemplateprofileinitiallytakenandstoredinmemory.Thistemplateprofilecontainstheechoesproducedbythebracing.Thus,usingthiscomparison,theechoesfromthebracingareignoredandthetruematerialechoisselected.Anothermethodevaluatestheechoprofilebasedonthecharacteristicsoftheechoanditslocationintheechoprofile.Thismethodfirstselectsthemostlikelyechointheprofilebyusingathresholdsimilartothatusedbytheanalogsignalprocessor.Oncethemostlikelycandidateshavebeenselected,thealgorithimsbegintoevaluateeachechobasedonthetypeofmaterialbeingmeasured.Ifthematerialisliquid,thentheprogramevaluatestheechoonamplitudeanditslocationintheechoprofile.Forexample,whenmeasuringaliquidsurfacethecharacteristicechoisnarrowandhighinamplitude.Liquidisveryreflectivetoultrasonicfrequencies;therefore,thetrueliquidlevelwillusuallybethefirstechoreceived;andinaliquidapplication,thealgorithmwouldselectthefirstechoreceivedwiththehighestamplitude.Forsolidsmeasurement,theprocessorselectsthemostlikelyechoesinthesamemanner,onlyusingdifferedselectioncriteriabasedonthedifferingcharacteristicsofthatsolidmaterial.Inthiscase,theprogramlooksforanechowhichisoflesseramplitudeandwiderthanthatofaliquidecho.Theechoiswiderbecausemostsolidmaterialshaveanangleofreposewhichreflectsmanydifferentechoesfromdifferingpointsontheangleofrepose.Thealgorithmmustnowlookfortheselectedechowhichisthehighestinamplitudeandthewidest.Therefore,theprocessorwillselecttheechowiththegreatestarea.



SummaryDigitalsignalprocessingandadvancedechoextractionalgorithmsmakeultrasonicsareliableandaccuratemethodofmeasuringsolidsandliquids.Ultrasonicinstrumentationisthusavaluableadditiontomanyoperations,providinglongtermandcost-effectivemeasurement.Thisbookprovidesathoroughlookatultrasonicleveltechnology,attheinstrumentation,andatthewidevarietyofapplicationsbestsuitedforitsuseasthisproventechnologycontinuestobeapreferredsolutiontomanymeasurementneeds.

1BuffaloSpringfield,“ForWhatIt’sWorth.”BuffaloSpringfield,1967.



ChapterThree

ThesoundandtheslurrySomebody'sshoutingUpatamountain

Onlymyownwordsreturn1

Thetransduceristhespeakerandmicrophoneintheultrasoniclevelsystem,producingtheultrasonicwavesandthensensingtheechoesastheyreturnsothecontrollercanrespondasprogrammed.SiemensMilltronicstransducershaveaprovenandextensiveapplicationhistory,andarethereliableeyesandearsofthousandsofapplicationsaroundtheworld.

Thischapterexaminestheroleofthetransducerinanultrasonicsensingsystem,howitismade,andhowitworks.

Topicsultrasonicsystemstransducersblankingdifferentialamplifiersechoprocessingreducingnoisebeamangleprofiles

TransducersandultrasonicsystemsTheultrasonicsensingsystemisavailableintwoformats:

singlesystems:thetransducerandthecontrollerelectronicsareintegratedintooneenclosure



compoundsystems:thetransducerandthecontrollerareseparateentities

SinglesystemsAsingleunitsystemisoftenreferredtoasa“leveltransmitter.”TheSiemensSITRANSProbeLUleveltransmittercombinestheelectronicsandtransducerinacompactsystemideallysuitedforliquidlevelmeasurementupto12meters(40ft).

ThetransducerportionoftheSITRANSProbeLUisinthelowerhalfofthedevice;thecontroller,electronicsandwiringareaareintheupperhalf.Leveltransmittersareversatileandaresuitableformanyapplications,includingbothgeneralpurposeuseinsafeareasanduseinhazardousareas,dependingonapprovals.

CompoundsystemsCompoundsystemsseparatetheultrasonictransducerfromthecontroller.Thetransducerismountedonthevesselwhilethecontrollerisinasafeareaawayfromtheapplicationinacontrolroomorafieldmountedelectricalpanel.Siemensoffersawidevarietyofcontrollersandtransducers,liketheSITRANSLUT400andEchomaxXRS-5,thatcanbematchedtosuitmanyapplications.



Transducerscarrymanysafetyapprovalsformountingandforuseinhazardousareas,andtheyaredesignedtowithstandruggedindustrialenvironments.Thetransducerisconnectedtothecontrollerbycable(eitherco-axialortwistedpair),receivestheelectricaltransmitpulse,andthensendsthereturnechopulsealongthesamewire.Thetransducerandcontrollercanbeseparateduptoadistanceof365meters(1200ft).

TransducersAtransducerissimplyadevicethatconvertsoneformofenergyintoanother.Thus,devicessuchasthespeakersconnectedtoanentertainmentsystemaretransducersbecausetheyconvertelectricalsignalsgeneratedbytheamplifierintothemusicyouhear.Amicrophoneisthereverseofaspeaker:atransducerconvertingsoundintoelectricalsignals.

Thetimerequiredtochangefromtransmittoreceivemodeisfinite.See“Blanking."

Theultrasonictransducerperformsbothfunctions.Likeaspeaker,itconvertsthehighfrequencyelectricalpulsefromthecontrollerintohighfrequencysound,andthenprojectsthesoundintothevessel.Andlikeamicrophone,itconvertsthesoundechobackintoanelectricalpulse,transmittingthissignalbacktothecontrollerforprocessing.Thetransducerdoesnottransmitandreceivesimultaneously,butconstantlychangesfromtransmitmodetoreceivemodemanytimespersecond.

Theheartoftheultrasonictransducerisapiezoelectricceramiccrystalthatvibrateswhenahighvoltagepulseisapplied,sendingoutsoundwaves.Conversely,whenthesoundwavesreturn,thevibrationscausethepiezoelectriccrystaltoproduceanelectricalsignalwhichisthensentbacktothecontrollerforinterpretation.Thedifferencebetweenthe



transmittedsignalandreceivedsignal,issignificant,andtheoutgoingtransmitcanbeseveralhundredvolts,whilethereceivedsignalisinthemicrovolttomillivoltrange.

Becausethereturnsignalissoslight,itcanbeaffectedbyanynumberofsituationalinfluences:mediumtemperatures,attenuation,andobstructions.Toachievemaximumperformancebenefitfromtheultrasonicsystem,alltheapplicationconditionsneedtobeconsideredwhendesigninganultrasoniclevelsystem.

TemperatureandtransducermaterialThetemperatureoftheapplicationcanaffecttheperformanceofthetransducer,asdoesitsconstancy,becausefluctuationsalsoaffectthereadingreliability.Transducerscompensatefortheseconditionsbyincorporatingtemperaturesensorsandbyusingtemperatureresistantmaterialsintheirconstructionsothatthereadingsareunaffectedbytheseconditions.Thetemperaturevariationeffectisgenerally0.17%foreverydegreecentigrade;soforeverydegreetheapplicationtemperaturefluctuates,thelevelmeasurementisaffectedby0.17%.

TemperaturesensorsWhentransducerswerefirstdeveloped,temperaturevariationsweremediatedbytheuseofanexternalsensorwhichtransmitteddatatothecontroller,whichthencompensatedforfluctuationsbyadjustingthereadingaccordingly.Theneedfortheexternalsensorwaseliminatedwhenanambientairtemperaturesensorwasincorporatedintothebodyofthetransducer.Makingthesensorpartofthetransducercircuitryalso



allowsthesensortousethesamewiresettotransmittemperaturedatatothecontroller.Siemensaddedtothisconveniencebyplacingthetemperaturesensorinapocketjustbehindthetransducerfaceandbyimprovingthecircuitry,enhancingsensorfunctionbyacceleratingthetemperatureprocessing.

Built-intemperaturecompensationimprovestheaccuracyofthesystemandreducesinstallationcost.

SoundanddifferentialamplifiersWhilenoisecanaffectthesystemfromoutside,itmayalsooccurwithinthesystemitself.Thisinfluenceisaconsequenceofthesystem'selectricalfunctionalityandthecablingrequirementsthatcreateoramplifynoise.Siemenshasdevelopedadifferentialreceiverinterfacethateliminatesorgreatlyreducesinducednoiseonboththepositiveandnegativewiresofatwistedpaircable.2

Transmissionandreceiptofbothelectricalandultrasonicsignals



Figure1:Theelectricalpulsesreceivedbythetransceivertendtobesmallerthantheinitialpulsesoutputbythedevice.

Therefore,accuratedistancemeasurementrequiresamplificationoftheelectricalsignals.

Forthedevicetocalculateadistanceaccurately,itmustamplifythereturningelectricalpulsesandanalyzethereturneddatausingechoprocessingalgorithms.Unfortunately,theamplificationprocedureusedonthereturningsignalsissensitivetotheeffectsofnoiseandthisiswherethedifferentialreceiverinterfacehasanumberofadvantagesoverthecommonsingle-endedreceiverinterface.

Single-endedreceiverTheamplifierwithinthecontrollerisresponsibleformagnifyingthereturningelectricalpulsesexistingbetweentheamplifier’spositiveandnegativeinputs.Forthecommonsingle-endedreceiverinterface(seeFigure2),thepositiveinputoftheamplifierisconnectedtothepositiveterminalofthetransducer,andthenegativeinputisconnectedtoground.Whenthedevicereceivessignalsfromthetransducer,itamplifiesthesignalexistingatthepositiveterminalwithrespecttoground.Fornow,ifthegroundisassumedtobeideal,theoutputoftheamplifierwillsimplybeamagnifiedversionofthesignalreturningalongthepositiveterminal.

Commonsingle-endedreceiverconnection



Figure2:Inacommonsingle-endedreceiverconnection,thepositiveinputoftheamplifierisconnectedtothepositiveterminalofthetransducerandthenegativeinputisconnectedtoground.

Intheeventwherethesignalalongthepositiveterminaliscontaminatedbynoise(i.e.environmentalnoiseproducedbymotors,near-byantennae,wirelessdevices,etc.),sincethegroundisassumedtobeideal,theamplifierwouldmagnifythisnoise(seeFigure3).Thisnoisecouldleadtoinaccuratedistancecalculationsbythedevice.

Theeffectsofnoiseonacommonsingle-endedconnection

Figure3:Theeffectofnoiseonacommonsingle-endedconnectionismagnifiedandmayleadtoinaccuratedistancecalculationsbythetransceiver.

DifferentialreceiverInthedifferentialreceiverconnection,thevoltageexistsbetweenthepositiveandnegativewiresofthecable.Thepositiveinputoftheamplifierconnectstothepositiveterminalofthetransducerandthenegativeinputconnectstothenegativeterminal.

Differentialreceiverconnection



Figure4:Inadifferentialreceiverconnection,thepositivewireisconnectedtothepositiveterminalofthetransducersandthenegativeinputisconnectedtothenegativeterminal.

Wherethepositiveandnegativewiresareinverycloseproximitytoeachother(common),anyenvironmentalnoiseoccurringononewirewillalsoexistontheother.Sinceadifferentialamplifiermagnifiesthedifferencebetweenthetwowires,anynoisecommontobothwires(hencetheterm“common-mode”noise)willnotappearattheoutputoftheamplifier(seeFigure5).

Theeffectsofnoiseonadifferentialconnection

Figure5Becauseadifferentialamplifiermagnifiesthedifferencebetweenthetwowires,anynoisecommontobothwireswillnotappearattheoutputoftheamplifier.

WhenaconnectionbetweenadevicewithadifferentialreceiverinterfaceliketheSITRANSLUT400andatransduceristobemade,ashieldedtwisted-paircableshouldbeused.Inthiscase,thepositivewireconnectstothepositiveterminalofthetransducer,thenegativewireconnectstothenegativeterminal,andtheshieldconnectstoground.Notethatneitherthepositivenorthenegativeterminalsarelinkedtoground.Sincethepositiveandnegativewiresaretwistedtogether,thereisahighlikelihoodthattheenvironmentalnoiseexistingonbothwireswillbe



essentiallythesame.Therefore,environmentalnoisewillbepresentintheformofcommon-modenoise,whichtheamplifierwillbeabletoeffectivelyremove.Alsovoltagesinducedontheshieldduetogroundloopswillhavenoeffect,sincethesignalexistsacrossthepositiveandnegativewires.

Differentialinterfacecombinedwiththephysicaltwistingofthewiresinthetwistedshielded-paircableenhancesthecommon-modenoiserejectionability,helpingtonegatenoiseinterference.

Applicationtemperature3

Ultrasonicinstrumentshaveahightemperaturetolerance.Formostapplications,hightemperatureisnotanissue,butinhotprocessapplicationswherethematerialcomesfromakilnordryer,thetransducerrequiresahightemperaturetolerance.Tomeetthesedemands,designadvanceshaveextendedthemaximumtemperaturerangeofmanytransducersto150°C(300°F).

Ultrasonictransducersremainextremelystableovertheiroperatingrangebecauseoftheiron-boardsensorsandtwo-wiredatatransmission,evenduringextremetemperaturefluctuationscommontomanyoperations.

HousingmaterialChemicalcompatibilityisanimportantapplicationconsideration;thetransducerhastobecompatiblewiththematerialbeingmeasured.Transducersareavailableinavarietyofmaterials,includingPTFE,ETFE,PVDF,CPVC,andCFM,andcanbematchedwithavarietyofapplicationmaterialconditions.

Attenuationisthedecreaseinthesoundsignalasitpassesthroughvariousmediaandtheinitialpower/vibrationofthesoundisabsorbedbyotherinfluences.



Theusershouldalwaysverifymaterialsuitabilitybycontactingthetransducermanufacturerorbyusingachemicalcompatibilitychartprovidedbythetransducermaterialmanufacturer.ChemicalcompatibilitychartsarealsoreadilyavailableontheInternet.

RangeandpowerThemaximumrangeofatransducerisnormallyproportionaltotheamountofpoweravailableandthefrequencyoftransmission.Thehighertheinitialtransmitpower,thebetterthechanceofgettinganecho.Thethickerthemediumthroughwhichthesoundtravels,themoreforceisrequiredtopushthesoundthroughit.Lowerfrequenciesarelessattenuatedwhentheypassthroughair,whichiswhyfoghornsaresolow-pitched.

Rangesquotedinthespecificationsheetsandinstructionbooksshouldbetakenasamaximum.Donotexceed!



Thematerialspresentinthemediumabsorb(attenuate)thesoundandaffectperformance.Thisgraph4showstheattenuationindecibelsofvarioussoundfrequencieswhenthetemperatureandhumiditylevelsareconstant:

Soat41kHz,theroundtripattenuationisapproximately55dBatarangeof15meters(50ft).Anechoof30dBatthemaximumratedrangeofatransducerisstrongenoughtoprocessandexceedthenoiselevelsinherentinmanyapplications;however,insomeinstances,echoesasweakas5dBcanbeprocessedwithhighconfidence.Knowingthis,thecontrollermustsendoutapulsetothetransducerthatisstrongenoughsothatintheafter-round-tripattenuationof55dBat41KHzata15meterrange,thereissufficientreturnechostrengthtoprocessthesignal.

Long-rangetransducersaredesignedtooperateatlowerfrequenciestotakeadvantageoflowerattenuationratesthatprovideastrongerechotothetransceiverforprocessing.Inexchangefortheextrapower,however,someresolutionislost.Butinlong-rangeapplicationsofgrains,powders,orpellets,thisgenerallydoesnotpresentaproblemasaccuracyrequirementsmaynotbeasstringent.

ConditionsConditionsaffectperformancebecausethesoundwavesneedtogothroughthemediumandareinfluencedbyotheroccupantsofthatspace.Dust,steam,andhighhumidityattenuatesoundandtherequireddistanceformeasurementmaynotbemet.Withoutanecho,thereisnothingfortheelectronicstoworkwith.Conversely,withaverysmallstainlesstank,itmaybebettertogotoalowerpowertransducerbecausemultipleechoesmayrequirechangingthealgorithm,aninconveniencetothecustomer.

Rule:iftheapplicationisonthelimitofthetransducer’srange,stepuptothenexttransducerforbetterreliability!

Dust



Mostsolidapplicationsaredusty.Inareaswheredustisextremelyheavy,keepingthetransducercleaniscriticalbecausematerialbuildupreducesthetransducer’sabilitytotransmitandreceive.Siemenstransducersusematerialswithgoodreleasecharacteristicswhich,combinedwithpulsatingdisplacement,oftenpreventbuild-upfrombeginning.

StillingwellsIfanapplicationisveryagitated,dusty,orhasalotofsurfacefoam,theseconditionsmaybeneutralizedusingastillingwell.Thestillingwellisasecondarypipeaccessingthetankcontentsandreflectingthesamecontentlevel.

Inaverysmallstainlesstank,gotoalowerpowertransducerbecausemultipleechoesmayrequirechangingthealgorithm.

Withstillingwells,lowerpowermaybebettersincethereisnospreadinglossbecausethesonicenergyiscontainedwithinthepipe.Inlaboratoryconditionsequivalenttoanemptywarehouse,oroutsideonacalmday,echoeshavebeenobtainedatmuchgreaterdistancesthanthenominalratingofthetransducers.However,inreal-worldapplications,usetheguidelinesdetailedabove.

Foamfacing



Impedancematchingfoamfacingcanimproveatransducer’spowerandrange.Impedancematchingprovidesgreateracousticpoweroutputandisveryusefulindustysituationswheretheparticlesintheaircauseattenuation.

Animpedancematchingpolypropyleneclosed-cellfoamfaceisdesignedforEchomaxXPStransducers.Theclosedcellpolypropylenehasahightemperatureratingof95°C(203°F)andisnotbotheredbydustormoisturegettingintothefoam.

MoistureontransducerfaceThefaceoftheXPStransducersisactiveandwillultrasonicallyevaporatethedroplets.Ifthereisabitofaslopetothetransducer(mountadegreeortwooffvertical),theextravibrationwillcausethedropletstomovetotheedgeandfalloff.

TransducerselectionSelectingtherighttransduceraffectsperformance,andthecriteriashouldbebasedonrange(distance)andpower.Forexample,insomepowderandplasticpelletapplications,ashorterrangeEchomaxXPS-15(operatingat44KHz)ismoreappropriatethanalong-rangeEchomaxXPS-40(operatingat21KHz)becausethehigherfrequencyyieldsabetterreflectionfromthematerialsurface.Alltheapplicationconditionsneedtobeconsidered,notjustdistance.

BlankingdistanceandheightplacementThelocationofthetransduceralsoinfluencesperformance.Theheartofatransducerisapiezoelectriccrystal;whenatransducerissentatransmitpulse,thepiezoelectriccrystalexpandsandcontractslengthwisetoproducetheultrasonicsoundsignal.Whenthetransmitpulsestops,thecrystalisnolongerexcitedanditsmechanical



vibrationbeginstodecay.Thisdecayhasafinitetimeperiodandisoftenreferredtoas“transducerringdown”duringwhichthetransducercannotreceiveanecho.

Properaiming,location,andmountingareotherimportantfactors.

Thetimeoftheringingisthenconvertedtodistance(D=VT)andrepresentsthespaceinfrontofthetransducerfacewheremeasurementisnotpossible.Thisspace,alsoknownasthe“blankingdistance”or“deadzone,”hasdecreaseddramaticallyovertheyearsastechnologyandresearchadvancedultrasonicmeasurementtechnology.Initially,theblankingdistancewasameterorevenmore,butithasbeenreducedto25centimeters(0.82ft)inthemostrecentsystems.

Otherfactorsliketemperatureandinstallationtechniquesalsoaffecttheblankingdistance:

Theringdownquantitydependsonthecrystalitselfaswellasthematerialsandconstructionoftheentiretransducer.

TemperatureHightemperaturetransducershavealongerblankingdistance.Whileringdowntakesthesameamountoftimeregardlessofthetransducer’stemperature,thespeedofsoundincreaseswithtemperature.ThereforewhenusingD=VT,agreatervelocityresultsinanincreaseddistance.Theblankingdistanceisstatedatthemaximumtransducertemperaturerating.

InstallationIfthetransducerisconnecteddirectlytoametalcouplerorifthemountingthreadsaretorquedtootightly,themountingarrangementactsaspartofthetransducerandwill“ring”witheachtransmitpulse.Toreduceringingonly,hand-tightenthetransducerintoablindflangeorontoaconduitadapter.Ifpossible,useaplasticconduitadapterratherthanametalone.



Foraflangedtransducer,usethesuppliedplasticboltsanddonotover-tighten.Useagasketbetweenthevesselflangeandthetransducerflange.

Transducerdesign:theheartofthematterThephysicaldesignoftoday’stransducerhousesdecadesofresearchandenhancements,distinguishingSiemensfromtherestoftheplayers.ThesetransducerdevelopmentshavemadeSiemensthebestinthebusinessandtheworldleaderinthefield.

Measuringdistanceisnotassimpleastimingthesoundwhenitbouncesback.Italsorequiresintelligencebecausesoundisindiscriminate.Itbouncesfromanythingandeverything,andsincemostapplicationsarefilledwithobstructionsandotherclutterthatinterfereswiththepathofsound,itrequiressophisticatedequipmenttodistinguishthereallevelechofromtherestofthebouncebacks.

Siemensultrasonicinstrumentationhasthesophisticatedtechnologythatevaluatestheechoesanddetermineswhichonesaretrueandwhicharefalse.

SummaryThetheoreticalprincipleofsoniclevelmeasurementissimple.Atransducerlocatedatthetopofabinorwelltransmitsapulseofsoundenergy.Thesoundreflectsfromthematerialsurfaceandtravelsbacktothetransducerwhereitisconvertedintoanelectricalpulse.Thetimedelayfromtransmissiontoreceivedechoisconvertedintodistanceandthemateriallevelisdetermined.

Inpractice,soniclevelmeasurementisabitmorecomplicatedasthereisnotjustasingleechofromthematerial,butmanyechoesreflectingfrombinwalls,beams,pipes,andwiresinthesoundpath.Furthermore,theactualechoqualitiescanvarygreatlyforthefollowingreasons:



soundattenuateswithdistance;thus,thedesiredechofromthematerialsurfacemaybeweakerthantheundesiredechoesthematerialsurfaceofsolidsisusuallyinclined,andthisspreadsandweakenstheechoelectricalnoisefrommotorsorcontrollerscaninterfereorbestrongerthantheecho

Distinguishingamongthemanyechoescanthusbeverydifficult,butitiscrucialforthesystemtobeeffectiveandtherealechoneedstobefound.Thehistoricalprogressionofthetechnologyisbasedonthissearchforthetrueecho.

1DeepPurple,"PicturesofHome."MachineHead,1972.2Thissectionwasfirstpublishedas,Ausder“Klemme”Füllstandmessung-intelligenteSchaltungstechnikvergrößertRauschabstand.GordonLi.MSRMagazin(Messen,Steuern,RegelnundAutomatisieren).Issue1-2(January/February2005)pages:16-17.3DougDuncan.“Ultrasonicsensors:Nowanevenbetterchoiceforsolidmaterialdetection,”InstrumentationandControlSystems.November1998.4From“TheTheoryofUltrasonicsandEchoRanging.”



ChapterFour

EchoprocessingMakinggooddecisionsisacrucialskillatanylevel.1

Ultrasonicstechnologyhasbeenusedforindustrialbinlevelmeasurementsincethe1940s.Sincethen,thetoolshaveevolvedtoovercometheacousticproblemsfacedinrealworldapplications.Complexcircuitrywithtimevaryinggain,automaticgaincontrol,rangetrackinggates,nearandfarblanking,noisesuppressionfilters,phaselockedloops,andotheradvanceshaveexpandedthecapabilitiesofsoniclevelmeasurement.Thesedevelopmentsallhaveonethingincommon:real-timeanalogprocessingofthesignalasitwasreceived.

Whileanalogprocessinggreatlyadvancedultrasonictechnologyaslevelmeasurementinstrumentation,italsohadtwomaindisadvantages:

First,askilledtechnicianwithascrewdriverandanoscilloscopewouldcarefullyadjusttheinstalledelectronicsforeachapplication,andthishadtobedonewhilethebinlevelwascycledupanddownseveraltimes.Thisisacostlyandtime-consumingprocess.Second,sincethesignalisprocessedasitisreceived,thereisnoopportunitytoanalyzeandcomparetheinformationstatisticallytoseeifitisevenpossibleorcorrect.Thusdataloggingwasnot



possible.

Siemensrecognizedthatanalog-basedinstrumentswouldneverbesufficientandfocuseditseffortsonmovingawayfromreal-timeprocessing.Engineerssoonrealizedthatplacingtheentirestreamofechoesintoastoredechoprofileinacomputer’smemorygavetheunittheopportunitytoexamineitsshots.Thecomputerthenprocessesandanalyzesthestoredechoprofiletoselectthetrueechoinamorereliablefashion.ThefirstproducttousethisrevolutionarytechniquewastheMilltronicsAiRangerIV,introducedin1984,andthissystemhasbeenineveryinstrumentsincethen,includingSITRANSLUT400andSITRANSProbeLU.Asaresult,echo-processingadjustmentsarenotgenerallyrequiredinmostapplications.

ThischapterpresentsSonicIntelligencefunctionalityandhowitrefinestheanalyticprocessdeterminingtrueechoandlevel.

TopicsEchoprocessingShotsandprofilesFiltersTimevaryingthreshold(TVT)EchoselectionFigureofmeritEchoprofilesEchoprocessingparametersNoise

Echoprocessing-intelligenceThepatentedecho-processingtechnologyembeddedinultrasoniclevelmeasurementproductsfromSiemensisknownasSonicIntelligence™2.SonicIntelligencedifferentiatesbetweentrueechoesfromthematerialbeingmeasuredandfalseechoesgeneratedbyobstructionsorelectricalnoise.Theresultisrepeatable,fast,andreliablemeasurement.



SonicIntelligenceisfield-proveninover1,000,000applicationsworldwide.

Thistechnologicaladvancementwasdevelopedinconsultationwithfieldserviceengineersandsupportedbyfielddatagainedfromdecadesofexperiencewithapplicationsinmanyindustriesandcontinuestoevolvetoday.Usinghigherordermathematicaltechniquesandalgorithmstoprovideintelligentprocessingofechoprofiles,this“knowledge-based”techniqueproducessuperiorperformanceandreliability.

SITRANSLUT400usesnextgenerationSonicIntelligenceforechoprocessing,providingadaptivedigitalfilteringofthetransducersignal.Forexample,whennoiselevelsarehigh,filtersareadjustedtomaximizethesignaltonoiseratio.ThisadvancedSonicIntelligencenotonlyallowsforbetterfiltering,butprovidesimprovedtrackingofechoes,andmoresophisticatedechopositioningalgorithms.

UnderstandingechoprocessingEchoprocessingisasimpleconceptandacomplexrealityastheinstrumentlooksateachgroupingofechoes(ashot)andprocessesthereturntodeterminethetrueecho.

Theshortshotusesanarrowtransmitpulsewhichreducestransducerringingtoprovideimprovedreliabilityforthedetectionofneartargets.Thelongshotusesawidetransmitpulsetoprovideastrongerreturnechotodetectmoredistanttargets.Bothshortandlongshotsareprocessed,andthenthebestisselectedwithabiasinfavoroftheshortshot.Onceanechoisselected,variousfiltersareappliedtostabilizethereading.



EventhoughSonicIntelligencewillselectthecorrectechoaftereverymeasurement,thereadingitselfmayfluctuateasaresultofchangingconditionswithinthebin.Averagingthereadingsreducesthefluctuationsbutcausesalaginresponsewhenthemateriallevelchanges.SonicIntelligenceusespowerfulstatisticaltechniques,togivestablereadingswhilestillallowingrapidresponsetoactualchangesinthemateriallevel.

ShotsandprofilesSolet’slookathowthesoftwarereadstheshotsandwhatitseesasthefollowingareimplemented:

filtersTimeVaryingThreshold(TVT)application



echoanalysis

TheechoprofileThecompleteprofileincludingtransmitandringdownisdisplayedandtheamountofblankingindexedinthesoftwareisshownonthebottomtrace.Theecholockwindow(orwindow)locksontotheselectedechoinordertoignorespuriousechoesfromagitatorbladesorrandomelectricalinterference.ATimeVaryingThreshold(TVT)curveprovidesareferenceforcomparingechoes.

SITRANSLUT400usesnextgenerationSonicIntelligenceforechoprocessing,providingadaptivedigitalfilteringofthetransducersignal.Forexample,ifnoiselevelsarehigh,filtersareadjustedtomaximizethesignaltonoiseratio.ThisadvancedSonicIntelligencenotonlyallowsforbetterfiltering,butprovidesimprovedtrackingofechoesandmoresophisticatedechopositioningalgorithms.

WhattheLUT400sees(or,moreaccurately,“hears”)fromatransmitpulseinanapplicationisstoredinadigitalformatandisreferredtoasan“echoprofile.”Thisprofileisadigitalrepresentationofthereturnedechoenergyversustime.

Findingthetrueecho



Astheechoesbouncebackfromthesurface,SonicIntelligencesoftwareparsestheinformationinitsgoaltofindthetrueecho.Theprocesscomprisesthreeactivecomponentsworkingtogetherintheselectionprocess:

1. Filters: enhancing the echoes and using Time Varying Threshold(TVT)toselect.

2. Trueecho:selection.

3. Selectedecho:verification.

One:FiltersFiltersarealgorithmprocessesinthesoftwarethattuneoutoutsideinterferencesandenhancetheechoesreturnedfromtheapplication.

ClippingfilterRemovesthehighspikesinthetimedomain,resultinginlessringinginthefilterandreducingtheimpactofhighnoiseontheprobabilityofpickingtherightecho.

DigitalbandpassfilterThismethodpermitsthedesignoftheoptimummatchedfilter,creatingthehighestprobabilityofselectingtherightechoovernoise.Eachtransducerhasabandpassfilterbasedonitstransmissionfrequency.

KalmanfilterThisalgorithmsmoothesandappliesdampingtoreadings,removingjitterandinstability.

TemperaturefilterAKalmanfilteralgorithmthatremovesjitterofthereportedtemperaturevaluecontributestoaccuratecalculationofthesoundvelocity.

SpikefilterElectricalnoiseproducesfalseechoeswhicharenarrowandhighcomparedtowiderechoesfromthematerialbeingmeasured.ThespikefilterinSonicIntelligenceusesthisdifferencetoidentifyandremove



electricalnoise.

Thespikefiltermeasuresthewidthofeachspikeandcutsoffanyspiketoonarrowtobeanecho.Theecholockwindowisthefirstlineofdefenseagainstrandomelectricalnoise,butthespikefiltereffectivelycorrectsforelectricalinterferencefrommachinerysuchasvariablefrequencydrives(VFDs).Thespikefilterwillneverremoveavalidecho.

NarrowechofilterManybinshavetargetsinthepathofthesoundwavethatproducefalseechoesthatcouldinterferewiththemeasurement.Thesemaybepipes,cables,orevenseamsinthebinwall.Inanarrowbin,itmaybeimpossibletomovethetransducerfarenoughawaytoavoidthesetargets.Thesetargetsproduceechoeswhichmakeitdifficulttoselectthecorrectechofromthematerialsurfaceinareliablemanner.



Insolids,theNarrowEchoFiltercanremoveundesiredechoesfromhardtargetssuchaspipes,beams,windows,orseams.That’sbecausetheseechoesarenarrowerthanthetrueechofromaninclinedsolidmaterialsurface.Inuse,thefilterisincreasedbysmallamountsuntiltheundesiredechoesareeliminated.Itisadvisabletomonitoroperationoveracompletefillandemptycycletoavoidsettingtoohighafiltervaluethatcouldwipeoutthetrueechoaswell.Thistechniquedoesnotapplytoliquidmeasurementwherethetrueechoisasnarrowastheundesiredecho.

ReformechoIndeepbins,thesoundwavefacesmanyobstaclesinitsjourneyfromtransducertomaterialsurfaceandbackagain.Theseobstaclesincludereflectionfromthebinwall,dust,aircurrents,changesinairdensity,andirregularitiesatthematerialsurface.Alltheseobstructionscombinetocreateafragmentedorsplinteredecho.Reformechobuildsthefragmentedechobackintoasingle,strong,well-definedechopulse.

Byincreasingreforminsmallamounts,theoperatorcanjointhepeaksofafragmentedechotoproducealarge,smoothecho.Usethisfeaturewithcautionbecauseifthereformistoolarge,thepeaksofunrelatedechoeswillbejoinedtogether.



EchoselectionalgorithmsAftertheechoprofilehasbeenenhanced,thefinaltaskisselectingthebestecho,ataskdeterminedbythebinconditions.

Two:Trueechoselection(selectionofechoreflectedbytheintendedtarget)ThisselectionoccurswhentheportionoftheechoprofileabovetheTimeVaryingThresholdmeetstheevaluationcriteriaofSonicIntelligence.Insignificantportionsoftheechoprofileoutsideofthemeasurementrange(e.g.FarRange)andbelowtheTVTcurveareautomaticallydisregarded.Theremainingportionsoftheechoprofileareevaluatedusingtheechoselectalgorithmandtheechoprofileportionprovidingthebestecho(confidence)isselected.

NOTE:Aconfidencevalueisastatictestofasinglesnapshotprofiletomaintainavalidreading;itrequiresthateachindividualprofilemaintainsitspeakabovethethreshold.Thewindowmaybelockedontheprofileforhoursorevendays,soiftheprofiledropsbelowtheTVTcurvejustonce,lossofechomayoccur.

TimeVaryingThreshold(TVT)Thetimevaryingthreshold(TVT)isusedasareferencetocompareechoesatdifferentpositionsintime.Afarechowillbeweakerbecausethesoundhastraveledagreaterdistance,butnearandfarechoesmust



becomparedinordertoselectthetrueecho.

Foragivenconditionofdust,temperature,orhumidity,theattenuationofsoundisusuallyuniformthroughoutthebin;therefore,theidealTVTisalinewithaslopeequaltotheattenuationofsoundindB/m.Thisslopeiscalculatedfromthedecliningportionoftheechoprofile.

TVTshaper(manualadjustment)TheshaperdividestheTVTcurveintoequalsegments,eachofwhichcanbeadjustedupordown.AnundesiredechocanbeignoredbyliftingtheTVTcurveatthepositionoftheecho.IftheTVTcurveisraisedtoomuch,however,thetrueechowillnotbedetectedwhenitisinthisregion.ItisnotnecessaryfortheTVTtocleartheundesiredecho,justcuttingitinhalfisusuallyenoughtode-emphasizetheundesiredecho.



TheadjustmentsrideupanddownwiththeTVTandmovehorizontallywhenthevelocitychanges.Allcalibrationpointsandrangesshouldbesetbeforeusingtheshaper.

Theshapercannotbeusedonechoesfromreflectionsofmaterialhang-upsbecausethefalseechopositionwillchangeifthematerialfallsoutofitshungupposition.

Autofalse-echosuppression(automaticTVTshaping)Thisfeatureautomaticallydetectsandsuppressesechoesfromvesselobstructions.PriortoactivatingtheAutoFalse-EchoSuppression,emptythetankasmuchaspossible.Ifthereisanagitator,itshouldbeoperating.DuringtheTVTLearnsession,thecontrollerfirespulsesandshapestheTVTaroundanyechofromanobstructionliketheagitator.ThisshapingiseasytoperformanddoesnotrequireaPC.

TheTVTwillthennotdroplowerthanthelearnedposition.

SITRANSLUT400hasadvancedtrackingabilityandcanfindtherealechoamongststationaryclutterechoes.Therefore,eveniftheechodropsbelowtheTVTcurve,itcanbeidentifiedwithnearcertaintyforapproximately30seconds.ThiscapabilityismeasuredbytheFigureofMerit(FoM)setting.

Therearefourselectionmethods:

measuretheareaofeachechomeasuretheheightofeachecho



measurethefirstmovingechoselectthefirstsignificantecho

FortheMultiRanger,LargestorFirstarethepreferredalgorithms.FortheAiRanger,togetherit’sALF.

ThesemethodscanbereferredtoasArea,Largest,andFirstalgorithms(ALF).AnothermethodusesTrackerwheretheuserselects/deselectsthealgorithmstandardsettings.SonicIntelligenceusesallfouralgorithmsoneachmeasurement.Foreachalgorithm,ascoreorconfidenceiscalculatedforeachechothatcrossestheTVTcurve,thenthescoresareaddeduptogiveatotalscoreforeachecho.Theechowiththehighesttotalscoreisdeemedtobethetrueechofromthematerialsurface.Thenetechoconfidenceistheconfidenceofthechosenechominustheconfidenceoftheechowiththenexthighestconfidencelevel;i.e.netconfidenceofthefirstchoiceisfirstchoiceminussecondchoice.

Occasionally,onealgorithmwillgivealowscoretothetrueechoandabetterscoretoafalseecho,buttheotheralgorithmswillpullthetotalscoreofthetrueechoup,andpushthetotalscoreofthefalseechodown.ThefinalselectedechoiscorrectbecauseSonicIntelligenceincorporatesadiversifiedportfolioofapplicationexperience.Foragivenbincondition,asinglealgorithmwillgivehigherechoconfidencebut,asbinconditionschange,anotheralgorithmmayberequired.Generally,usingallfouralgorithmsprovidesformorereliableoperationovertime.However,trainedoperatorscanadjustthedeviceparametersandfine-tunethealgorithmstosuittheirapplication.

SiemensMilltronicsequipmentalsocontainsanechoprocessingalgorithmcall“bLF,”alsoknownas“BestofLargestatFirst.”ThisalgorithmrunstheLargestalgorithmandFirstalgorithmandselectstheechowiththehighestconfidencevalue.ItdoesnotsumthevaluesasintheALFalgorithm.bLFisthebestchoiceforshortrangeliquidapplications.



AnotheralgorithmisTrueFirst(TF).ThisalgorithmselectsthefirstechothatcrossestheTVTcurve.Useinliquidsapplicationsfreeofobstructionswhenconfidenceoffirstechoishigh.

TheTR(TR)Trackeralgorithmselectstheechothatclosesttothetransducerandismoving.AnechothatisbelowtheTVTlineandmovingcanbedetectedbythisalgorithmandwhenitisnottrackinganecho,itbehavesthesameasbLF.

NOTE:OnlyuseTRalgorithminprocessapplicationswitheitherofthesetwoconditions:

continuouslevelchangesariskoffixedobstructionsthatcouldinterferewithtruelevelresultinginlowconfidence.

Three:SelectedechoverificationThisverificationisautomatic.Theposition(relationintimeaftertransmit)ofthenewechoiscomparedtothatofthepreviouslyacceptedecho.WhenthenewechoiswithintheEchoLockWindow,itisaccepted,updatingdisplays,outputs,andrelays.Ifthenewechoisoutsideofthewindow,itisnotaccepteduntilecholockrequirementsaresatisfied.

ThesethreeprocessesworkawayinthebackgroundastheSonicIntelligencesoftwaredeterminesthebestecho.However,theechoescanbefurthertunedshoulditbenecessary.

EchoqualityEchoqualityandconfidencecanbefurthertunedusingtheinformationprovidedbythedevicefromthefollowingfeatures.

Figureofmerit



FigureofMerit(FOM)measuresthequalityofthereportedprocessvalue:highervaluesrepresentbetterquality.Evenwhenalowconfidencevalueexists,ahighFOMwillensurethetrueechohasbeenselected.Approximately20readingsareusedtosupporttheFOMvalue.

EXAMPLEFOMgreaterthan75%=goodqualityFOMlessthan50%=poorqualityContributionstotheFoM:

successofthetracking(howcloselycanthenextlevelversustheactualnextlevelbepredicted)levelofnoiseconfidenceofthelastechotimeintervalsincelastvalidechospeedatwhichtheprocessismovingqualityoftheechoshapeandhowithelpsthecalculationoftheechoposition

NOTE:IfFoMislow,reducethenoiseintheprocess,orchecktheinstallationtoincreasesignalquality.



EchoparameterfinetuningSonicIntelligencesoftwareeliminatestheneedforecho-processingadjustmentsinallbutthemostdifficultapplications(lessthan1%).Iffinetuningisrequired,operatorscanusethemoreadvancedadjustmentparametersavailableinSiemenstransceivers.

Onlyoneortwoecho-tuningparametersshouldbeadjustedatatime,sothattheimpactofeachadjustmentcanbecarefullymonitoredforacompletefillandemptycycle.Adjustmentsmadetoreachaconfidencefigureatacertainbinlevelmaynotholdunderchangingbinlevels.Donotrelysolelyontheconfidencefigure,butlookattheechoprofileanddecideiftheechoiswelldefinedundervariousconditionsandwillprovidereliabletrackingoflevelsfromemptytofull.Thisisespeciallyimportantduringaimingandmounting.

EchoprofilesTheechoprofile,agraphicrepresentationofthereflectedechoreceivedbythetransducer,isanimportantdiagnostictool.Digitallygenerated,theprofileisstoredbythetransceiverandcanbeviewedusingseveraltypesofconfigurationsoftware,includingSIMATICPDM(ProcessDeviceManager),AMS,FDTs,DolphinPlus,andSuperSonex.

Theechostartsoutasananalogsignal:

Thissignalisdigitizedbythetransceiver’sA/Dconverterandchangedintoanechoprofile,whichisameasurementoftheechoenergyversustime.



Toreadtheprofile,startattheleftside,whichrepresentsthetanktop,andmoveacross.Thefartherright,thefartherdownintothetanktheshotgoes,readingthedistance.Theupwardspikesindicateechoesandthestrengthindecibels.

ProfilecomponentsThereareseveralcomponentstoanechoprofile,eachrevealingasignificantaspectoftheecho.Theechoprofilecomponentsareshowninthefollowingdiagrams:

Echoprofile



Ringdown



Theleadingedgeoftheechoprofileisthedecayofthetransmitpulse,alsoknownasthe“transducerringdown.”Thisistheportionoftheechoprofileshowingthegradualrecoveryofthecrystalafterashothasbeentaken.

TVTcurve(TimeVaryingThreshold)

TheTVTcurveisadigitallygeneratedthresholdlevelthatactsasavalidationpointforthereceivedechoes.Itisadynamicthresholdlevel;anypartoftheprofileabovethecurvewillbeincludedintheechovalidationprocess.

Echomarker



Theechomarkerrepresentswhatthecontrollerhasprocessedasthecorrectecho(ormateriallevel)forthatparticularechoprofile.Itmayormaynotpresentthisasthelevelreading.TheEchoLockWindowcontrolsthelevelreadingoutput.Theheightofthemarkerrepresentstheechoconfidence;thelargertheheight,thebettertheconfidencethatthisistheechothatmostrepresentsthetruelevelforthisparticularprofile.

Echolockwindow



TheEchoLockWindow(orsimplytheWindow)controlshowfarthelevelcanchangebetweenshots.Fromshottoshot,thelevelchangecannotexceedthewidthoftheecholockwindow.Iftheechomarkerfallswithinthewidthofthewindow,thecontrollerwilloutputthelevelasindicatedbytheechomarkerandre-centerthewindowontheecho.Iftheechomarkerfallsoutsidethewindow(e.g.marksanechofromabladeofanagitator),thenthecontrollerwillignorethemarkedechoandoutputalevelrepresentedbythewindow(whichalsorepresentsthelastvalidreading).

Thewidthofthewindowissetbythemeasurementresponse(ordamping)parameter.Iftheapplicationlevelchangesrapidly(aprocessvessel),programafastmeasurementresponseandthewindowwidthwillbequitewide.Iftheapplicationhasaslowmovinglevel(astoragevessel),thensetthemeasurementresponseparametertoslowandthewindowwidthwillbequitenarrow.

Ifthereisasuddenchangeinlevelandtheechomarker(thistimerepresentingthetruelevelandnotafalseechofromanagitatorblade)isoutsidethewidthofthewindow,thecontrollermaintainstheleveloutput



atthelevelrepresentedbythewindow,thelastvalidreading.Italsobeginstowidenthewindowatthemeasurementresponserate.Iftheechomarkerpointsatthesameechooutsidethewindowforfiveshotsinarow,thecontrolleracceptsthatthisisnowtruelevelandchangestheleveloutput(thedisplay,mAoutput,ordigitaloutput)atthemeasurementresponserateinthedirectionofthetruelevel.Thewindowcontinuestowidenatthemeasurementresponserateandoncethetrueechoiswithinthewindowwidth,thewindowwillshrinkbacktoitsnormalsizeandre-centeritselfonthetrueecho.

Echoprocessingparameters

Thevaluesofsomeoftheadvancedechoprocessingparametersareplacedontheechoprofileasaconvenienceandcanbeusedasareferencewhensubsequentlyviewingtheprofiles.

Includedarethevaluesforthefollowing:

echoalgorithmspikefilter



narrowechofilterechoreformTVTtypeconfidencethresholdshortshotrangeshortshotbiaswindowsillpercentagenearTVTdB

Echoconfidence

Echoconfidencerepresentsthecertainty,orconfidence,thatthechosenechoisthecorrectecho.ThevalueisgeneratedfromoneoftheechoprocessingalgorithmslikeALForbLF(seeSonicIntelligence).Confidenceisshownintwoareas:attheselectedechoandbesidetheechomarker.Thevaluesbesidetheechoshowtheconfidencevaluesgeneratedbyindividualalgorithms.IntheaboveprofileitshowsL:20and



F:20–meaningthattheLargestalgorithmandtheFirstalgorithmeachgeneratedaconfidencevalueof20.Theconfidencevaluebesidetheechomarkerisshownas:

Thisindicatestheshortshotconfidenceis0,thenetlongshotconfidenceis20,andthebracketsaroundthe20indicatethatthelongshotwasusedtoprocessandoutputthelevelmeasurementreading.

Theecho

Thisgraphshowsanecho,withspikesthataresharporgradual(dependingonthematerial)risingintheechoprofile.Sharpechoesarisefromflatmaterialsurfaceslikeliquids,asintheaboveprofile.Gradual,widerechoescomefromsolidmaterial;clinker,coal,orgrains,aremoregradualintheirrise,andoftenlookliketheechobelowfromplasticpellets:



EchostrengthThestrengthoftheselectedechoindBabove1microvoltRMSiscalculatedasechostrength.

Theechoprofilesareaninvaluableassetwhentroubleshooting,andatechniciancandeterminethefollowingfromtheprofilebasedontheechoes:

goodechostrengthandlowconfidencemeansmultipleechoestogetthelevelreadinglowechostrengthandlowconfidencecanmeantheechoisweak,theresultofpooraiming,orhighattenuationfromdust,steam,orC02.Thesurfacemayalsobefoamyorpoorlyreflectivefromextremeturbulence.



NoiseNoiseinanultrasonicsystemcanalsobegeneratedbyelectricalinterferencereceivedfromthetransducercables.Thisinterfereswiththeechoreadingandentersthecontrollerfrommanysources:

mainpowermAoutputexternaltemperaturesensor(ifused)radiatedfromnearbyelectricaldevices

Theelectricalnoiseispickedupontheprofile.Thetwolinesatthebottomleftrepresentthenoiseparameter.ThetopoftheboldverticallineisthepeaknoiseindB;thesmallhorizontallineindicatestheaveragenoise.Inthisexample,thepeaknoiseis5dBandtheaveragenoiseis-3dB.

Thebestmethodforensuringthelowestnoisepossibleistousetherecommendedtransducercable.ThenewerSiemensMilltronicscontrollers(SITRANSLUT400,MultiRanger100/200,HydroRanger200)useshieldedtwistedpaircablewhileestablishedmodels(SITRANSLU)



useRG62A/Ucoaxialcable.Theshieldsmustbeproperlyconnected,andusegroundedmetalconduittoshieldthecablefromelectricalnoiseandtophysicallyprotectthecablefromdamage.

Ingeneral,averagenoiselevelsabove30dBarecauseforconcernandnoiseshouldbereduced.

ThelevelsofnoisepresentatthereceiverinputcanbeviewedonthedeviceLocalUserInterfaceastheaveragenoiseandthepeaknoise.Ingeneral,themostusefulvalueistheaveragenoisebecausethepeaknoiseisaspikethatcanbefilteredout.Averagenoise,however,istheoverallbaselinenoise.Iftheechostrengthdoesnotexceedthebaselinenoise,therewillbeproblemsdiscerningtheechofromtheambientnoise.

AdaptiveprofileblendingWhennotinahighnoiseapplication,theLUT400processeseveryshotindividually.Ifnoiselevelsincreaseaboveathresholdof35dB,theSITRANSLUT400blendsmultipleprofilestogether,increasingthereliabilityofechoselectionandpositiondetection.Thisreplacesthepreviousprocessofaveraginganumberofshotsandrespondsmorequicklytofastchangingmateriallevels.

NoiseinterferenceWithnotransducerattached,thenoiseisunder5dB,whichiscalledthenoisefloor.Ifthevaluewithatransducerattachedisgreaterthan5dB,thensignalprocessingproblemscanoccurbecausethegreaterthenoise,thelessthedistancethatcanbemeasured.Anyaveragenoiselevelgreaterthan30dBisgenerallycauseforconcernunlessthedistanceismuchshorterthanthemaximumspecifiedforthetransduceranditpowersitswaythroughthenoise.

Determiningthenoisesource



Noisecanbefromeitherelectricalinterferenceorfromanacousticobstructionthatintervenesanddistortstheintendedecho.Thus,thefirststepistodeterminethenoisesource.

Startbydisconnectingthetransducerfromthetransceiver.Ifthemeasurednoiseisabove5dB,gotoNon-transducernoisesourcesbelow.Fornoiselevelsbelow5dB,proceedwiththefollowing:

1. Connectonlytheshieldwireofthetransducertothecontroller.Ifthemeasured noise is below 5 dB, continuewith the next step. If thenoiseisabove5dB,gotoCommonwiringproblems.

2. Connect the white and black transducer wires to the controller.Recordtheaveragenoise.

3. Remove the positive wire of the transducer. Record the averagenoise.

4. Reconnect thepositivewireand remove thenegativewire.Recordtheaveragenoise.

UsetheNoiseModificationtabletodeterminetheappropriatenextstep.Thetermshigher,lower,andunchangedrefertothenoiserecordedintheprevioussteps.

Noisemodificationtable

noise -removed +removed Goto:

higher higher

unchanged

lower

Reducingelectricalnoise

Commonwiringproblems

Reducingacousticnoise

unchanged higher

unchanged

lower

Reducingelectricalnoise

ContactSiemens


lower higher

unchanged

lower






Non-transducernoisesourcesRemoveallinputandoutputcablesfromthecontrollerindividuallywhilemonitoringthenoise.Ifremovingacablereducesthenoise,thatcablemaybepickingupnoisefromadjacentelectricalequipment.Althoughcontrollersaredesignedtoworknearheavyindustrialequipmentsuchasvariablespeeddrives,donotlocatethemnearhighvoltagewiresorswitchgear.

Becauseofhighcosts,filteringcablesarenotrecommendedunlessallotheroptionshavebeenexhausted.

Ensurethatlowvoltagecablesarenotbeingrunadjacenttohighvoltagecablesorneartoelectricalnoisegeneratorssuchasvariablespeeddrives.

Movingtheelectronicsafewmetersawayfromthesourceofnoisewillfixtheproblem.Shieldingtheelectronicsisanotheroption,albeitexpensiveanddifficulttoinstallproperly;theshieldingboxmustenclosethecontrollerelectronicscompletely,andallwiresmustbebroughttotheboxthroughgroundedmetalconduit.

CommonwiringproblemsTheinstallationwiringcanalsopresentnoiseproblems.

makesurethatthetransducershieldwireisconnectedattheelectronicsendonly.Donotgrounditatanyotherlocation.donotconnectthetransducershieldwiretothewhitewire.(AppliesonlytotheSITRANSLUT400,MultiRanger100/200,HydroRanger200,andSITRANSLUC500)theexposedtransducershieldwiremustbeasshortaspossible.connectionsbetweenthewiresuppliedwiththetransducer,andanycustomerinstalledextensionwireshouldbedoneingroundedmetaljunctionboxes.



ForSITRANSLUT400,LUC500,MultiRanger100/200,andHydro-Ranger200,thetransducerextensionwiremustbeshieldedtwistedpair.ForSITRANSLUseries,AiRangerseries,HydroRangerPlus,andMiniRangerPlus,useRG-62A/Uco-axialcablefornoisereductionpurposes.Seetheinstallationsectionofthecontrollermanualforcorrectcablespecifications.

NOTE:OnSiemenstransducers,thewhitewireisnegativeandtheblackwireispositive.Iftheextensionwireiscoloreddifferently,makesurethatitiswiredconsistently.

Reducingelectricalnoiseensurethatthetransducercabledoesnotrunparalleltoothercablescarryinghighvoltageorcurrentmovethetransducercableawayfromnoisegeneratorssuchasvariablespeeddrivesputthetransducercableingroundedmetalconduitfilterthenoisesource

AcousticnoiseToconfirmthattheproblemisacoustical,placeseverallayersofcardboardoverthefaceofthetransducer.Ifthenoiseisreduced,thenoiseisdefinitelyacoustical.

Reducingacousticnoisemovethetransducerawayfromthenoisesourceuseastillingwellinstallarubberorfoambushingorgasketbetweenthetransducerandthemountingsurfacerelocateorinsulatethenoisesourcechangethefrequencyofthenoise.Thecontrollerisonlysensitivetonoisebetween25KHzand65KHz



SummarySonicintelligencebeatsattheheartofSiemensultrasonictechnology.Derivedfromthecumulativeexperienceofoveramillionultrasonicapplications,thissophisticatedechoprocessingfocusesalasersharpeyeonthetruelevelintheapplication.

1Drucker,Peter.1909-2005.2™SonicIntelligenceisatrademarkofSiemensMilltronicsProcessInstruments.



ChapterFive

InstallationThereisjoyinrepetition,

thereisjoyinrepetition,thereisjoyinrepetition.1

Ultrasoniclevelmeasurementinstrumentationoffersnon-contactingtechnologythatisvirtuallymaintenancefreeandcosteffectiveinmanyapplications,fromthewaterandwastewaterindustriestosolidsandliquidsmeasurementinavarietyofindustrialsettings.

Ultrasonicsystemsuseatransducertosendelectronicpulsestoacontrollerwhichinterpretsthemanddeterminesleveldistance.IntegratedsystemsliketheSITRANSProbeLUhousethetransducerandcontrollertogetherandcanalsofunctionastransmitterswithinanetwork,usingthelatestincommunicationhardwareandsoftwaretotransmitdatabacktoitssourceforimmediateprocessing.Theycanoperatepumpsandalarmsdirectlyorsenddatathroughcommunicationsystems.



Othersystemsseparatethetransducerfromthecontroller,andonlythetransducerisactuallyattheapplication.Thecontrollercanbeasfaras365meters(1200ft)away.Theapplicationcanbeconfiguredandmanagedfromadistance;thusindangerousorawkwardsituations,nooneneedstoreturntothesiteaftertheinitialinstallation.

Ultrasonictransducersareveryeasytoinstallandmaintain,ensuringmanyyearsofreliableoperation.Thischapterdiscussesinstallationrequirementsandbestpracticestomaximizethebenefitsofanultrasonicapplication.

Topicstransducerselectionlocationandobstructionsvesselstanksandaccessnozzles,standpipes,stillpipescablingopenvessels,flumes,weirsliftstationspositioncontrolapprovals

InstallationconditionsarethesameforthetransducersensorsonlyorfortransmittersliketheSITRANSProbeLU.Thecontrollersaregenerallymountedawayfromtheapplicationswheretheycanbeconfiguredin



comfortandsafety.

SelecttherighttransducerTheEchomaxXRS-5isapopulartransducerchoice.Withameasurementrangeof0.3meters(oneft)toeightmeters(26ft)onliquidsandslurries,itissuitableformostshorttomid-rangeapplicationsinthewaterandwastewaterindustries.

Forshort-rangesolidsapplications,theEchomaxXPS-10providesahighpoweroutputsuitablefordustyapplications.

Forapplicationsbeyondeightmeters(26ft)andupto15meters(50ft),EchomaxXPS-15transduceroffersthemostaccurateperformanceforsolids,liquids,andslurryapplications.

Applicationsbeyond15meters(50ft)requiretheXPS-30orXPS-40transducerswithlowerfrequenciesandmorepowerfuloutput.

Manyconditionscanaffecttheperformanceofyourultrasonicsystem,andtheyneedtobenotedwhenchoosingatransducer.Theapplicationenvironmentalsoinfluencestheperformance,andinthischapterwediscusstheactualinstallationcriteriaforthetransducersafteryouhavedecidedwhichtransducerisappropriateforyourapplicationandiscompatiblewiththecontroller.



LocationTheactualphysicallocationofthetransducerisveryimportantforoptimalperformance,andthereareanumberoffactorsthatmustbeconsidereddependingontheapplicationtype.Thusthetransducermountingformeasuringopenchannelflowisdifferentfrommeasuring



liquidsinavesselanddifferentagainfrommeasuringsolids.However,regardlessoftheapplicationtype,theonecommonconditiontoavoidinanyapplicationistheobstruction.

Keepobjectsoutoftheultrasonicconetoreducefalseechoes.

ObstructionsObstructionsarethemostimportantapplicationelementstobeawareofastheyblockthesoundsignalpath.Typicalvesselobstructionsincludeladders,pumps,braces,lights,agitators,walkways,andloadingchutes.Ifobstructionsareunavoidable,choosethelocationwheretherearetheleastnumberofobstructions.Thetransducermustbeableto“see”thematerialbeingmeasured,andabeam,pipe,orstructuralbracewillblocktheviewandaffectthereading.Obviously,theclearertheaccesstothematerial,thebettertheperformance.

Becausetheultrasonicpulseradiatesinaconeshapefromthefaceofthetransducer,keepingobjectsoutsideofthissignalconereducesthechanceoffalseechoesbeingrecorded.Thetransducerbeamanglespecifiesthedegreeofthecone(seeillustrationbelow)wheretheultrasonicpulse’spowerislowerbythreedB(decibels).



ClosedvesselsInclosedvessels,locatethetransduceronastandpipeorstillpipe,oranyaccessportornozzlethatoffersanunobstructedviewofthesurfacetobemonitored.Thestandpipeorstillpipecannegatetheblankingrequirementsbydistancingthetransducerfromthematerial.

TanksThevarietyofvesselsmeasuredbyultrasonicsisextensive,fromsmallonemeterhigh(3.3ft)plasticcontainersofwoodglueresinstothreemeterhigh(10ft)stainlesssteeltanksfulloficecreambaseto60meter(200ft)concretegrainsilos.Ultrasonicmeasurementhasveryfewlimitationswhenitcomestovesselsizeorgeometry;itsimplyneedsaclearpathforthesoundtotraveltothematerialbeingmeasured.Theshapeofthetankmatterslittle.

Althoughtankorvesselsizescanvary,themajorityarevariationsononlyafewstandardshapes.Transducerlocationcanchangeslightlydependingupontheshapeofthevessel.

Theseshapesinclude:

FlatbottomtanksCommonapplicationsincludewastewaterwetwells.Locatethetransducerasclosetothecenteraspossibleandawayfromobstructionsinthebeampath.Ifmountinginthecenterisnotpossible,maintaina10:1ratiowhenmountingclosetothesideofthevessel.

NOTE:Foreverytenmetersverticalmeasurement,locatethetransduceronemeterfromthesidetopreventanyinterferingechoes.



Conebottom/parabolicbottomtanksFortanksusedinliquidmaterialapplications,mountthetransducerinthecentersothatmeasurementtothebottomoftheconeispossible.Ifthisisnotpossible,programthecontrollersothatthebottomofthetankisthetopofthecone.

Ifthematerialisasolid(i.e.grain),thenatransducerwithanaimingdeviceshouldbeusedandthetransduceraimedtowardsthebottomoftheconetoensuremeasurementintothedrawpoint.

HorizontaltanksMountthetransducerasclosetothetopcenterofthevesselaspossibletomakeuseofalltheavailablespan.

NOTE:Echoprocessingsoftwarecanignorereflectionsfromsupportbeams,weldbeads,ladder,ormaterialbuildupalongthevesselsides.



TankaccessTherearemanywaystoaccessasealedtankorvessel:

cutholeand/orEasyAimernozzlesstandpipesstillpipessidepipes

Cuthole/EasyAimer:sometanksorvesselshavenoentryroutes,butcanbeaccessedbycuttingaholeorusinganexistingtrapdoortomountthattransducer.TheSiemensMilltronicsEasyAimerassistsinaimingthetransducerthroughanaccessportintothevesselatananglerequiredtogettheaccuratereading.Attachthetransducertotheaimingkitusingthecouplingprovidedwiththekitandthenaimpastthetransducersothatthesoundpathisperpendiculartothematerialsurface.

NOTE:Besuretolocatetheaccessportsothatnoobstructionsareinthebeampath.

TheEasyAimeraimsthetransducertothelowleveldrawpoint.Thetransducercanberevolvedthrough360°andangledat0to27°offvertical.Itcanwithstand100kPa(onebaror15psigauge)pressurewithaggressiveenvironments.



Nozzles:aprotrudingaccesspipelocatedonthesurfaceofthevessel.Ashortoutlet,orinlet,pipeprojectingfromtheendorsideofahollowvessel.



Standpipe:anaccesspipethatprotrudesthroughavesselwallandispresentonboththeoutsideandtheinsideofthetank,andmaybeusedasamountingplatform.



Beawareofthefollowingwhenusinganozzleorstandpipe.Whenmountingflangedtransducerstoclosedtopvessels:



besurenobuildupformsinsidethestandpipe(maycreatefalsereadings)eliminateweldsandseamsastheyhavethesameeffectasbuildupheightshouldbelessthanthreemultiplesofthediameter(H<3D)minimumdiameteris76millimeters(3")ifheightislessthan150millimeters(6"),factoryblankingcanbeused.Ifheightisgreaterthan150millimeters,increaseblankingto150millimetersbeyondthebottomofstandpipe,orextendstandpipeintotankandcuttheendata45°angle.

StandpipeinstallationCuttheendofthestandpipeona45°angleandremoveanyburrsfromcutting.Thisanglewillhelpmatchtheimpedanceoftheairinsidethepipewiththerestoftheapplicationenvironment.A90°cutcouldcreate



aninterferingechoattheendofthestandpipeandreducetheconfidencevalueoftherealecho.

Forstandpipeinstallations,useafactorybondedflangedtransducerorsplitflangekitthatwillreadilymatetotheflangedstandpipe.Anotheroptionistohangthetransducerfromablindflange.

Thestandpipeshouldbeasshort,andthediameteraslarge,aspossible.The-3dBconeofthesoundbeamshouldnotintersectthestandpipewallinapplicationsopeningintoavesselorlargerarea.Otherwise,additionalblankingwillberequiredtocompensatefortheinterferencezonecreatedbytheopening.

Stillpipes/StillingtubesAstillpipe(essentiallyanextendedstandpipe)maybeusedforturbulentliquidapplicationsasitextendsfurtherdownintothevessel,andisalsohelpfulinfoamyconditionsbyisolatingthesurface.



Astillpipeissimplyasmoothwalledpipethatextendsfromthetopofthevesseltothebottom.Thelowerendofthepipeisopentoallowthecleanfreeflowingliquidtomoveupthepipe.Inanapplicationwherethevesselisemptiedcompletely,itmaybepossibleforthefoamtoenterthebottomofthestillpipe.Inthiscase,aJ-tubeisrecommended.TheJ-tubeisastillpipewithan180°elbowatthebottom.Whenthevesselisemptiedtherewillalwaysbeasmallamountofliquidintheelbow,anditwillnotallowanyofthefoamtopassintothestillpipe.

Thesameconsiderationsforastandpipeshouldbeappliedtostillpipe:

donotperforateordrillholesalongthelengthofthestillingwellweldsandcouplingscanaffectthereliabilityoflevelmeasurementavoidbuilduporotherdebrisontheinsideofthewellwallensurethereisaventholeatthetopofthestillingwell

SidepipesSidepipesaresimilartostillpipesbutareontheoutsideofthevesselandiscomparabletoasightglass.Thelevelisreflectedinthejoinedpipe.Sidepipeseliminatefalseechoesfromobstructionsandfillstreams,and



areoftenusedinsumpsandwells.Thefollowingmustbenoted:

pipesshouldbeseamlesswithaminimum150millimeter(6")diameterpipeshouldbeventedatthetoppipemustbekeptcleanofbuildup

FlangesTransducerscanbemountedwithavarietyofflanges:

bondedflangesfornon-corrosiveapplicationsPTFE–facedflangesforcorrosiveapplicationssplitflangesforfieldretrofitformountingonaflangedstandpipe

Overtighteningthemountinghardwarecanleadtotransducerringing.



Tightentheflangeboltsevenlytoensureagoodsealbetweenthematingflanges,butdonotovertighten.Thiscanadverselyaffectperformance.Handtighteningshouldbesufficient.

LiquidapplicationsForbestresultsinliquidlevelmeasurement,thetransducermustbeperpendiculartothematerialsurface.Whetheritisthroughastandpipe,nozzle,orpositionedinthevesselusinganexistingopeningoranewlycutone.



Solidsapplications



Notethefollowingwheninstallingthetransduceronatank:

Inmosttanks,thetransducershouldbecenteredasmuchaspossible(withoutinterferencefrominlet)foroptimumreadingrange.Whetherthetankisemptyorfull,itmustcontainitsnormalvaporconditions.Whetherthetankisemptyorfull,itshouldbeatitsnormaltemperature.Thetransducershouldbeperpendiculartotheangleofreposeofthematerial,whichusuallymeansmountingittoonesideandatanangle.



Inconebottomtanks,aimthetransduceratthedrawpointatthecenterofthecone.Aimthetransducerawayfromseams,structuresandirregularitiesinthebinwall.Locatethetransducerawayfromthematerialinflow.Onfluid-likesolids,aimthetransducerperpendiculartothematerialsurface.Ondualdischargebins,aimthetransduceratthedrawordischargepointtoensureaccuratereadingsonemptying.UseEasyAimer.Keeptransducerawayfromfillpoints,asthematerialenteringthevesselcouldreflectthesoundpulseandgiveanincorrectlevelreading.Lookoutforratholingwherethedischargehascreatedadrainholethatcangiveincorrectlevelreadings.Bridging,wherethedischargedmaterialdoesnotshow,alsoleadstoincorrectlevelreadings.

ProtectionForsolidsapplicationswherethetransducercancomeincontactwithmaterial,suchasinarockboxorcrusher,protectthetransducerfromflyingrocksbysurroundingitwithawirecage.Securetheinstallationby



connectingasafetychainfromthetransducertothemountingsurface.

UsepropercablingCableselectionisaveryimportanttoensureproperfunctioningofthetransducer.Allwiring,conduit,andjunctionboxesaretobeinstalledaccordingtoalllocallaws,rules,andregulationsand/orinsurancecompanyrequirements.Refertoproductmanualsforwiretypeandconnectionsforspecifictransducermodels.

Installametaljunctionboxandtwoconductorterminalstripsataneasilyaccessiblelocation.Terminatecablesperthetransducerinstallationmanual.Ensurethatthecableshieldsareisolatedfromtheground.Failuretoproperlyinsulatethetransducershieldcancauseashorttotheground.



Groundedmetalconduitisrequiredbetweenthetransducerandthemetaljunctionbox.Groundedflexconduitisacceptable.Rigidmetalconduitshouldbeinstalledfromthejunctionboxtotheelectronicspackage.InthecaseofmultiplepointsystemsliketheSITRANSLU10,asingleconduitcanbeusedforalltransducercables.Iftransducercablesruninthesameconduitorincloseproximitytoeachother,besuretosynchronizethetransceivers(seedeviceinstructionmanual)topreventcrossinterference.

Transducersallhaveintegralcableswith“pigtail”leadsattheend.Thelengthofintegralcablecanbeselectedwhenorderingandareavailableinlengthsofupto100meters(328ft);however,thefivemeter(16.5ft)andtenmeter(32ft)lengthsaremostpopular.

Thepigtailendscanbedirectlyconnectedtothecontroller’sterminalblocks,orthecablecanbeextendedusingafield-mountedjunctionboxandadditionalcable,uptoatotallengthof365meters(1200ft).Theadditionalcabletypedependsonthecontroller,notthetransducer.Forextendedrunsbeyondthetransducer’sintegralcablealwayschecktheproductmanualforrecommendedcabletype.Somecontrollers,likethe



SITRANSLUT400andMultiRanger200,use18AWGshielded,twistedpaircable;othermodels,liketheSITRANSLU10,useRG62Ucoaxcabletoextendthelengthofthetransducercable.

Alltransducercableshouldbemountedingroundedmetalconduittoprovidethebestelectromagneticnoiseshieldingandphysicalprotectionofthecableitself.Donotruncablesnearhighvoltageorcurrentruns,contractors,orSCRcontroldrives.

DiagnosticsoftwareFordifficultinstallationsinvolvingexcessivedust,turbulence,obstructions,orverynarrowwells,diagnosticsoftwareisavailabletohelpfine-tunethetransducer’saimandtosetparameters.SiemensMilltronicsusesSIMATICPDMforviewingechoprofilesandtodiagnoseechoproperties.SupportforDTMsandothertypesofconfigurationsoftwareisavailableforsomemodels.

MatchenvironmenttemperatureIfatransducerbecomessignificantlywarmerorcoolerthantheaverageairtemperatureintheapplicationenvironment,itmayaffectaccuracybecausethespeedofsoundchangeswithtemperature.Althoughsome



transducershavebuilt-intemperaturecompensationfeatures,it’salwaysbesttomountatransducerwhereitwillsharethesameairtemperatureastherestoftheapplicationenvironment.

Fortransducersmountedoutdoorsindirectsunlight,provideasunshield.Ifthereisasignificanttemperaturedifferencebetweenthemediumandthesensorsurface,connectanexternaltemperaturesensortothecontrollerforincreasedaccuracy.

OpenvesselsLocatethetransducerascloseaspossibletothemaximumheightofthematerialbeingmeasuredwithoutinfringingontheblankingdistance.Theblankingdistancevariesamongmodels,sochecktheproductmanualforblankingdistanceinstructionsrelatedtoyourtransducer.

MountingbracketsTheseversatilebracketsprovidesturdyplatformsforopenvesselsandforopenchannelmonitoring.Manufacturedfrom304stainlesssteel(1.4301),thesebracketscomeinavarietyofshapestofitanyapplication.

Openchannelmeters:weirsandflumesOpenchannelflowoccurswhenliquidflowsinachannelwithafreesurfaceopentoatmospheresuchasstreams,rivers,irrigationcanals,andditches.Non-pressurizedpartiallyfilledpipes,includingstormsewers,sanitarysewers,andculvertsalsoqualify.Openchannelflowconditionsarecommonlyfoundinwastewatertreatmentsystems,industrialwastesystems,andirrigationsystems.



Inanopenchannel,pressureisnottransmittedfromoneendtotheotherendofthefluidlikethatinafullyflowingpipe,andonlytheforceofgravityonthefluidcausestheopenchannelflow.

Oneofthetime-provenandcommonmethodsofmeasuringflowusesaprimarydevicetorestricttheflowofliquidsothatamathematicalrelationshipexistsbetweentheliquiddepth(headlevel)andtheflowrateorvelocityofthewater.

Therearetwotypesofprimarydevices:weirsandflumes.

WeirsWeirsarethemostcommontypeofprimarydevicesusedtomeasureopenchannelflow.Aweirisadambuiltacrossachannelandtheliquidflowsoverit,oftenthereisacutoutornotch,andtheweirisgenerallynamedfortheshapeofthenotch.Aweiristhesimplestandoldesttypeofchannelflowmeasuringdevice.



Amathematicalrelationshipcanbederivedtocalculatethedischargethroughthesharp-crestedweirs.



FlumesAflumeisaventuridevice2placedwithinachanneltorestricttheflowandproduceahead(level)/flowraterelationship.TheflowinducedisbetweencriticalandsupercriticalflowlevelssoonlyoneheadmeasurementisrequiredtomeasureflowQ.

Mostflumesaredesignedtopasstheflowsthroughacriticalstateforaspecifiedheadrange,providedflumesareinstalled,maintained,andoperatedwithinthespecifiedrange.

Commonflumesinclude:

ParshallflumeRectangularflumePalmer-Bowlusflume

Ultrasoniclevelmeasurementdevicesareideallysuitedtomeasuringwaterlevelinprimarydevices.Thenon-contactingnatureofultrasonicsallowsformeasurementwithoutdisruptingtheflow;contactdevicesusedformeasuringheadlevelwouldactuallydisruptthelaminarflowandaffectthehead/flowrelationshipandtheoverallaccuracyoftheflowmeasurement.Thesurfaceofthewaterissmooth(ideallythereisnoturbulence)andthisprovidesaperfectreflectingsurfaceforsoundwaves.Ultrasonicdevicescanalsoprovideintegrationoftheinstantaneousflowratetoatotalizedamount.



Theoverallaccuracyofopenchannelflowmeasurementisdependentonthefollowing:

theprimaryelementselectionanddesignproperinstallationoftheprimarydevicetheeffectoftheapproachflowtheeffectsofthedischargeflowtheliquidbeingmeasuredthesecondarymeasuringdevicefieldcalibrationoftheprimaryelement(provingthatitdoesperformasintended)fieldcalibrationofthesecondarydevice

Thissectionfocusesonthesecondarydevice,theultrasonicopenchannelmeter,andthefield-mountedtransducer.Manytextsandguidelinesareavailablethatfocusontheprimarydeviceanditsinstallationcriteria;pleaserefertotheseforselectingandinstallingaflumeorweirproperly(seeISCOHandbook)orwww.usbr.gov/pmts/hydraulics_lab/pubs/wmm/cover.html

Theprimaryrequirementforaccuratemeasurementisthattheapproachingflowintoaflumeoroveraweirmustbetranquilandnon-turbulent.Thisisperhapsthemostimportantcriteriawheninstallingaprimarydeviceandalsohasaneffectontheaccuracyofthesecondarydevice.Iftheflowisturbulentintheapproachchannelthenthelevelwillnotbestable,causingdifficultiesforthesecondarydevicetolockontoalevelthatisrepresentativeoftheactualflowrate.

TransducerlocationThelocationofthetransducer,eveniftheflowissmoothandtranquil,isimportantiftheheadversusflowrelationshipistobemaintained.Forstandardweirs,thetransducershouldbelocatedupstreamminimumthreetimesthemaximumheadlevelasshownbelow:


http://www.usbr.gov/pmts/hydraulics_lab/pubs/wmm/cover.html


BS-3680V-notchweirISO1438/1(BS-3680)thinplateV-notchweirrequiresthatthetransducerbelocatedfourtofivetimesthemaximumheadlevelbackfromtheweirplate:



ParshallflumesForflumes,thelocationofthetransducerdependsupontheflumetype.CommoninNorthAmerica,Parshallflumeshavetheheadmeasuredat2/3thelengthoftheconvergingsectionfromthebeginningofthethroatsection:



BS-3680/ISO4359rectangularflumeAnISO4359(BS-3680)rectangularflumeheadlevelmeasuresfourtofivetimesthemaximumheadlevelupstreamasshowninthefollowingdiagram:



PipelineflumesTwotypesofflumesaredesignedtofitdirectlyinpipelinesinmanholes:Palmer-BowlusflumesandLeopoldLagcoflumes,andtheyaresizedaccordingtothepipediameter.Thetransducerlocationsdifferbetweenthesetypes;however,bothdependuponthepipediameter.TheupstreamlocationofthetransducerinaPalmer-Bowlusflumeisthepipediameter‘D’dividedbytwo,asshown:



TheLeopoldLagcoFlumeheadlevelmeasurementrequiresthetransducertobelocatedasshowninthefollowingtable:

Flumesize(pipediameter

ininches)

Pointmeasurement

centimeters inches

12 2.5 115 3.2 1.25

18 4.4 1.75

21 5.1 224 6.4 2.530 7.6 342 8.9 3.548 10.2 454 11.4 4.560 12.7 566 14.0 5.572 15.2 6



Tipsforeffectiveopenchannelflowmeasurement

Ensuretheprimarydevice(weirorflume)istherighttypeandsizefortheexpectedflowrate,andensureitisinstalledproperly.Discrepanciesfromthestandarddesign,dimensions,orsetupwilladverselyaffecttheaccuracyofflowmeasurementdevices.Ensurethatitisproperlycleanedandmaintained.Anybuildupofsedimentorvegetationcaninfluenceflowandflowmeasurement.Checkupstreamconditionsthatmaycreatewavesorsurging.Hydraulicjumps,flowpipes,ordropsinapproachpipeslocatedclosetotheflumecaninterferewithmeasurement.Wheninstallingflowmeasurementdevices,followtheinstallationguidelinesintheinstructionmanualtoensurecorrectsetupandtobeawareofanylimitations.Fieldcalibrationoftheprimaryelementwilltellyouiftheactualheadcorrespondstothehead-to-flowcalibrationinformationsuppliedbythemanufacturer.Ifnot,anewcurvecanbedeterminedthrough



fieldtesting.Thisisessentialonspecialapplicationsornon-standardweirsandflumes.Installtheheadmeasuringdeviceinarelativelycalm,stableportionofthechannel.Itshouldnotbepositionedinachannelapproachthathashighvelocityofwater,turbulence,gates,valves,pumps,orasuddenchangeinsection.Makesurethemeasurementdevicehasbeenproperlyzeroedinreferencetotheprimarydevice.Whentheflumeisempty,yourlevelsensorshouldreadzero.

MaintenanceIfsignificantperformancechangesareobserved,shutdownthelevelmeasurementsystemandinspectit,startingwiththetransducer.Ensurethetransducerisstillfirmlymounted,wipethefaceifithasbecomesoiled,andcheckthewiringconduittoensureitisallsound.Ifthetransducerworksproperly,checkthevesselsidesfornewobstructionsormaterialbuildup.

Ifthesoundpathisclear,performdiagnosticsatthecontroller.Troubleshootinginformationisclearlymarkedintheinstructionmanual,andotherproceduresincludeanalyzingtheechoprofileforechoquality(strength,confidence,andnoise).

Generally,lowmaintenanceisakeyadvantageofultrasonictransducers.Thepowerfulpulsingactionmakesthefaceself-cleaning.Becausetransducersarenon-contacting,thereisnomaterialbuildup,avoidingthenuisance,danger,andexpenseinvolvedincleaning,adjusting,andrepairingcontactingdevices.

LiftstationsLiftstations,alsoknownaspumpstationsorwetwells,areessentiallyverticallymounted,flatbottomvesselsthathappentobebuiltintotheground.Theyarepartofgravityfedsewagecollectionsystemsandareusedtocollectsewageatonepointandthenpumpit(orliftit)toahigherelevationtoeventuallyendupatthewastewatertreatmentfacility.



Liftstationsarealsofoundattheinlettothewastewatertreatmentfacilityitself.Thewetwelldiffersfromasimpleverticallymountedflatbottomvesselbythepresenceofequipmentinsidethewell:pumps,chains,inletanddischargepipes,back-upfloats,powerlinestothepumps,andladderrungs.Liftstationenvironmentsarealsoverycorrosiveanddirty,andthewatercancontainsolids;thuscontactdevices,likefloats,canprovetobeunreliableovertimeasmaterialbuildupandconstantcontactwearsonthesedevices.Ultrasonictransducers,anon-contactingtechnology,aremountedabovethesewageandonlycomeincontactwithsewageduringabnormalfloodconditions.Thusultrasoniclevelmeasurementprovidesnearmaintenance-freeoperationformanyyears.

Installthetransduceronasturdybracketorhangfrommetalconduit.Themountingheightshouldatleast30centimeters(12”)abovetheexpectedmaximumlevel;locatethetransducerasfarawayaspossiblefromtheinletpipe,pumps,ladderrungs,floats,thewetwellwall,andotherobstructions.Ifextremelyturbulentorfoamy,useastillingwellandfollowtheinstallationguidelines.

Wetwelltransducerselection:

shortrangewetwells[0to8m(0to26ft)]:XRS-5shortrangewellswithobstructedbeampath:XPS-15deeperwells:XPS-15verynarrowwetwells:XPS-30

Floodalert



Ifthetransducerissubmerged,especiallyinapplicationssuchasafloodedwetwell,useatransducerwithasubmergenceshieldthatmaintainsanairpocketinfrontofthetransducer.Thecontrollerrecognizestheuniqueechocreatedbytheairpocket,andthecontrolleroutputsahighlevelreading.

Wheninstallingasubmergenceshield,ensureitisproperlyseatedandevenacrossthetransducer.Checkforleaksbyplacingtheassembledunitinabucketofwaterandseeifanybubblesleakout.Leaksindicatetheshieldhasnotbeenpulleddownfarenoughtoproperlyseatthepressureclips.

NOTE:Asyouselectthetransducer,youalsoneedtoselectacompatiblecontrollertoprocessthesignalfromthetransducertoprovidethefollowing:

levelmonitoringdataloggingadvancedecho-processingtechnologypumpcontrolfunctionsremotemonitoring

Allcontrollermodelsofferbacklitdisplaysforeasyreadabilityandotheradvancedfeaturesthatcanimproveplantefficiency.Consideryourspecificapplicationneedsagainstthemanyfeaturesthatareavailable.

Positioncontrol



Ultrasonicsensingtechnologyhasotherusesthatareoutsideoflevelmeasurementbutthatoperateonsimilarprinciples.Thetransducersactasdistancesensors,indicatingproximityandactivatingalarmsormotorsorswitches.Thisultrasonicpositioningcontrolrequiresthetransducertobemountedhorizontallyandisveryeffectiveintheshippingindustryforoperatingoverheadcargocranesandintheminingindustryformanagingcoalloadingconveyors.

HazardousapprovalsTransducerandtransmittersareinstalledinpotentiallyexplosiveenvironments.Greatcareandeffortistakenduringthedevelopmentoftransducerstoensuretheyaresafeforuseandmeetorexceedtheapprovalrequirementsnecessaryforinstallationintheseenvironments.Notonlymusttheyperformtothedistanceandtemperaturerangesspecified,theymustalsodososafelyinhazardousorexplosiveenvironments.

Undermostgoverningelectricalcodes,itisuptotheusertoensurethatthetransducerortransmitterbeinginstalledhasthenecessaryapprovalstomeettheminimumareaclassificationoftheapplication.TransducersfromSiemensMilltronicscomewithawiderangeofapprovalstomeetthedemandsoftheapplicationsthathaveexplosiveenvironments.Theyvaryslightlyfromcountrytocountryastheworldhasnotadoptedaschemeforglobalapprovals.

ApprovalsSiemensultrasonictransducersaredesignedtomeettherequirementstobeusedinbothgasanddustatmospheresandarecertifiedbyvariousagenciesaroundtheworld.Itisimportantwhenspecifyingandinstalling



anyequipmentinalocationthatisclassifiedashazardoustofollowalllocalelectricalcodesandguidelinesandtopayparticularattentiontothespecifiedratings.

NOTES:Thefiretriangleorcombustiontriangleillustratestheconditionsrequiredformostfires.Threeelementsareneeded:heatorspark,fuel,andanoxidizingagent(usuallyoxygen).Fireispreventedorextinguishedwhenanyoftheconditionsareremoved.

Intheworldofelectricalengineering,ahazardouslocationiswhenconcentrationsofflammablegases,vapors,ordustsoccur.Electricalequipmentinstalledintheselocationsisespeciallydesignedandtestedtoensureitdoesnotinitiateanexplosionthrougharcingcontactsorhighsurfacetemperature.

ControllerinstallationWhilethetransducer/compoundinstrumentinstallationmustbecarefullyplannedbecauseofitsproximitytotheapplication,thecontrollerinstallationcanbedeterminedbytheoperator’srequirements.Thus,iftheoperatorisneartheapplication,thecontrollercanbeplacedcloseby.However,becausethecontrollercanbeinstalledasfarawayas365meters(1200ft),itcanalsobeplacedindoorsandawayfromtheelementswhereitmaybeinstalledindependentlyorinarackasoneofanumberofinstruments.



Whethertheunitiswallmountedorinstalledinarackorpanelwithotherinstrumentsdoesnotaffectperformance.Theyarethesame,regardlessofmountingdesigns.

MountinginstructionsThewallmountandpanelmountunitsinstalldifferentlyandthemanualscontainthespecificinstructions.

Wallmountedunitsmustbemounteddirectlytoawallortoelectricalcabinetbackpanel.Alternatesurfacesmustbestrongenoughtosupportfourtimestheweightoftheunit.

Rackandpanelmountedunitswillfitintoexistingslotsor,aswiththeSITRANSLUT400,willrequiremakingacutouttoaccommodatetheunit.Afullsizecutouttemplateisprovidedwithyourunitormaybedownloadedfromwww.siemens.com/level.

WiringCableisbroughtineitherdirectlythroughthecableglandsorthroughconduit,dependingontheinstallationrequirements:

Cableglands:ifthepurchasedunitdoesnothavepre-drilledcableglandholesorknockout,youneedtodrilltheentryholes.Makesureyouremovethemainboard,beingcarefulnottodamagetheelectronicswithstaticelectricity.Makesurecableglandholesdonotinterferewiththelowerareasontheterminalblock,circuitboard,orcommunicationcard.



http://www.siemens.com/level

Afterlooselyattachingtheglandstotheenclosure,threadthecablesthrough,keepingthepowercableseparatefromthesignalcables.Thentightenglandtoaensurewaterproofsealwhenwiringiscompleted.

Conduit:youneedtodrilltheentryholesorremovetheknockouts,somakesureyouremovethemainboard,beingcarefulnottodamagetheelectronicswithstaticelectricity.Makesureconduitholesdonotinterferewiththelowerareasontheterminalblock,circuitboard,orcommunicationscard.Attachtheconduittotheenclosureusingonlyapprovedsuitablesizehubsforwatertightapplication.Reinstallthemainboardwiththemountingscrews.

NOTES:

PerforminstallationonlybyqualifiedpersonnelandinaccordancewithlocalgoverningregulationsFollowpropergroundingprocedures.Thisproductissusceptibletoelectrostaticshock.Allfieldwiringmusthaveinsulationsuitableforatleast250V.HazardousvoltageispresentontransducerterminalsduringoperationSupplyACandDCterminalsfromapprovedsourcesUsegroundingtypebushingsandjumperssothenon-metallicenclosuredoesnotprovidegroundingbetweenconduitconnectionsEnsureambienttemperatureisalwayswithinitsapprovedrange.Typically-20to50°C(-5to122°F)Mountunitsodisplaywindowisatshoulderlevelandeasyaccessforprogrammingisprovided.MakesuremountingsurfaceisfreefromvibrationLeavesufficientroomtoswingunitlidopenforclearaccessAvoidexposuretodirectsunlight(Provideasunshieldtoavoiddirectsunlight.)Avoidproximitytohighvoltage/currentruns,contacts,SCR,orvariablefrequencymotorspeedcontrollers



SummaryUltrasonicsisaversatileandfriendlytechnologyformanylevelapplications,buttheinstallationrequirementsmustbemetforoptimalperformance.Situatingthesensorortransducerinthepropervessellocation,followingallthesafetyregulationsandapprovalrequirements,andaccountingfortemperatureandpressureconditionswillallensurereliable,accurateperformance.Alwaysaccountfortheconditionswhenchoosingaleveltechnology,andthosewhicharemoreproblematicforultrasonics–dust,vacuum,interference–canbehandledbytheSITRANSradarline.

1Prince,“JoyInRepetition.”GraffitiBridge,1990.2Anydevicethatrestrictstheflowandregulatesitthroughameasurablepoint.



ChapterSix

ApplicationsI’macosmopolitansophisticateofculture

andintelligence.Theculminationoftechnologyandcivilizedexperience.1

Ultrasoniclevelinstrumentsarenotexclusivetoanyoneindustryandarewidelyusedacrossmanybusinessesandapplications.However,therearecertainapplicationswhereSiemensMilltronicsultrasoniclevelinstrumentsoperateparticularlyeffectivelyandaccurately.Acrosstheglobeandoveramillionstrong,theseultrasonicleveldevicesarefoundinthewater/wastewater(W/WW)industry;inmining,aggregate,andcement(MAC)applications;andinthechemicalmarkets.

Regardlessofthetypeofapplication,however,theprimaryrequirementforallindustriesistobeabletomeasurelevelaccurately,consistently,andcosteffectively.Ultrasoniclevelmeasurementmeetstheseneeds



andhasbecometheselectedsolutionformanyindustriessincethe1970s.

ApplicationsMarketslikewater/wastewaterandmining,aggregate,andcementemploylevelmeasurementformanydifferentpurposes,includingprocesscontrolandinventorymonitoring.Eachindustryhasarichhistoryofinstrumentationdevelopment.Ascompetitiongrowsandresourcesarestrained,controllingprocessesandinventoriesisincreasinglycrucialtothebottomline.Accuracyandreliabilitybecomeparamountandcloserattentionispaidtotheinstrumentsusedtomeasureinventoryandcontrolprocesses.Measuringandcontrollingthelevelofmaterialscontainedinstorageandprocessvessels,suchastanks,wells,reservoirs,ponds,bins,andhoppersisoneofthemostcommonproceduresofindustrialinstrumentation.

Inalltheseapplications,ultrasonicsprovidestwotypesoflevelmeasurement:

pointmeasurementcontinuous

Thepointlevelcanalsobecombinedwiththecontinuousleveltoprovidesafetyredundancy.

Notthatlongago,binsandsilosweremeasuredbyknottedropesorbysightlines,withemployeesclimbingtothetopofthecontainerorinsomecasesintothecontaineritself.Thistypeofmeasurementbecameimpractical,andoccasionallydangerous,andcompaniessoughtoutinstrumentationwhichwasaccurateandreliable,andcouldbemonitoredincontrolroomsoractivatedfromremotelocations.Plumbbobsandcontactswitchescouldnotstanduptothestrenuousdemandsofmanyoftheapplications,sonon-contactingultrasoniclevelmeasurementasdevelopedbySiemensMilltronicsinthe1970sand1980swasintroduced



tothemarket.TheruggedreliabilityofSiemensMilltronicsinstrumentslikeTheProbeandtheMultiRangerquicklyproveditselfinvaluableforthefollowing:

reducespillage(overflow)–environmental,losscontrol,legislationcostaccounting–inventoryqualitycontrol–processcontrolbylevelreductionofinventoryinprocess–smallervesselspumpprotection–protectfromrunningdry

TopicsThischapterdiscussestheseapplications,focusingonthefollowingindustries:

cementminingwater/wastewaterfoodchemical

Cement





Thecementindustry,similartomining,reliedonrudimentarylevelmeasurementsystemsformanyyears.Plumbbobsoryo-yos,tiltswitches,andmanualdipsprovidedmostoftheinventoryandprocessinformation.Inthe1970sand1980s,ultrasonicmeasurementappearedonthescenewithsomeoftheearlyMilltronicsAiRangersandLRtransducers,findingmanyusesinthecementindustry.

Theproductionoffinishedcementrequiresnumerouslevelinstrumentsalongtheway,operatingintwocapacities:

asprocesscontrollers,activatingpumps,belts,alarms,andotheractionsasinventorymanagers,monitoringmateriallevelsinsilosandbins

Thecementprocesschartindicatesthemanyareaswhereultrasonicinstrumentsoperateinthecementproductionprocess.OtherSiemensMilltronicsequipment,likebeltscales,weighfeeders,andprocessprotectioninstrumentsalsoplayvitalrolesintheproductionofcement,reinforcingSiemens’roleasatotalsolutionprovider.

PrimarycrushersGyratoryconecrushersarethemostcommon,andtherearegenerallytwomainapplicationsattheprimarycrusher.



Truckpositioning–thetransducerishorizontallymountedinthepathofthereversingtruckandiswiredintoacircuitwhichcontrolsredandgreenlights.Asthetruckapproaches,theultrasonicsystemcontinuouslymonitorsitsposition.Whenitistheproperpositionfordumping,analarmrelayclosesandthegreenlightisactivated,signalingtothedriverthattheloadmaybesafelydumpedintothecrusher.



Rockbox–locatedbelowthecrusher,theultrasonicsystemmonitorsthelevelofthecrushedrock.Alarmsaresettoindicateaclogintheoutfeedandtoindicatewhenaloadcanbesafelydumpedintothecrusher.Alowlevelalarmcanbeprogrammedtomaintainaprotectivelayeroforeintherockboxtopreventfeederdamage.



QuarrystockpilesThecrushedlimestoneistransportedfromthecrushertoastockpilebyastackerconveyor.Theultrasonictransducermonitorsstackoutprofilesandprovidesinventoryestimatesinstockpilestoensureuniformstackout.

Anultrasonictransducermountedontheheadoftheconveyormonitorsthedistancefromthedischargetothetopofthestockpile.Whenthedistancebetweenthetworeachestheprogrammedsetpoint,analarmtriggers,signalingtheneedtoraiseorrotatetheconveyortoanewposition.Thisinventorymanagementisacommonapplicationforultrasonicssystemswheretheruggeddesignandremotepositioningofthecontrollermakeitanidealtechnologyfortheseconditions.

SecondarycrusherInthesetypicallynoisy,wet,anddirtyapplications,ultrasonictransducerssensethelevelofmaterialinthesurgebins.Ultrasonicsystemsarealsousedatin-feedchutestocrushers,monitoringforpluggedchutes.



Here,thePointekULS200monitorsthechuteattheendofaconveyor.Ifthechuteplugs,arelayintheULS200closesimmediately,notifyingtheuserthataproblemexistsandshuttingdowntheconveyor.

RawmillfeedsilosCrushedoreistransportedfromthesecondarycrusherstotherawmillfeedstoragesilo.Hereanultrasonicsystemmonitorstheleveloforeinthesilo.



Thisapplicationisstrictlyinventorymanagement,astheultrasonicsystemmonitorsthecontentlevelsonly.

RawmillTherawmillistypicallyarollermillthatpulverizesrawmaterial,includingadditives,intoafinepowderwhichisthentransportedtothekilnfeed.Blendedrawmaterialsarecontinuouslyfedintotherawmill.

Theultrasonicsystemmonitorstheheightofthemillrollersabovethetable,essentiallymonitoringbeddepth.Operatorsintegratematerialfeedratewiththerollerheighttomaintainaconsistentbeddepth,improvingmillingefficiencyandpreventingtherollersfromstrikingthemilltable.

KilnfeedsiloCrushedmaterialfromtherawmillistransportedtothekilnfeedsilo(sometimescalledContinuousFeedSiloasmaterialisconstantlyfedinandoutofthissilo)whereitisstoredandpreheatedinpreparationfordeliveryintothekilnitself.Ultrasonicsmonitorsthelevelwithinthesesilos,butwithonlyalimitedrangeduetotheextremelydustyandturbulentenvironment.

Inrecentyears,manykilnfeedsiloshavebeenoutfittedwithSiemensSITRANSLR560radarleveltransmitterswithgreatsuccessatovercomingtheharshenvironments.Ultrasonicsmaywork,however,



dependingonthedustlevels,andisacost-effectivealternativetoradarinappropriateapplications.

Clinkerstorage

Thematerialleavingthehotkilniscalledclinker.Ranginginsizefromdusttofistsizedclumps,theclinkerisstoredinsilosbeforebeinggroundintoafinepowder.Becauseithascomeoutofthekiln,theclinkerisquitehot.

Toworkeffectively,powerfulhightemperaturetransducersliketheXLT-60measurethelevelintheclinkersilos.Becauseclinkerapplications,althoughdusty,arenotasdustyaskilnfeedsilosorfinishedcementsilos,ultrasonicsisaviablechoiceforthisapplication;however,moreusersareswitchingtoSITRANSLR560radarbecauseofitsimprovedperformance.



AdditivebinsandcoalstoragesilosThesebinscontainmaterialsthatareaddedtotherawmillprocessandaremixedwiththecrushedlimestonebeforethekiln.Theyalsoholdthematerialsthatareaddedduringthefinalgrindingoftheclinker.Thesebinscontainsand,ironore,flyash,gypsum,plaster,orothermaterialsusedtoadjustthecompositionofthecement.



Thecoalsilosstorethecoalthatisburnedinthekiln–theheatfromtheburningcoalisresponsibleforthechemicalchangesoftherawfeedintoclinker.Ultrasonicsystemsmonitorthelevelinthesebinsforinventorypurposes.

FinishedcementsilosThesesiloscontainfinishedcement.Oncetheclinkerandotheradditiveshavegonethroughtheballmills,thematerialisreducedtoaveryfinepowderandisconveyedtostoragesiloswhereitwaitsforbulkshippingviatrainortrucking,orforfurtherproductionintobagged,finishedcement.



Finishedcementisextremelyfineandthereisverylittlemoisture,whichmakesthisapplicationverydusty.Theperformanceofultrasonicsystemsonthisapplicationisinconsistent–itdependsonmanyfactorsincludingsiloheight,dustcollectionsystem,transducerlocation,transduceraiming,andmethodoffilling.Likethekilnfeedsilos,thisapplicationwastraditionallymonitoredbyanultrasoniclevelsystem.Incaseswherethedustistoogreat,aSITRANSLR560radarleveltransmitteroperateswithgreatsuccess.

MiningInventorymanagementandprocesscontrolintheminingindustrywasaroughbusiness.Thenatureoftheproductmadeitdifficulttoassessvolumeaccuratelyandmostofthecontrolwasdonemanually.Mechanicalmeasurementreliedonyo-yos,oroccasionallynuclearmeasurementforpointlevelcontrol.However,nucleartechnologyisveryexpensiveandhasitsownsafetyconcernsandyo-yosarepronetobreakdown.Processeswerealsovisuallymonitoredbutoftenbrokedownwhenthemonitorwasnotwatchingorawayfromhispost.Crushersjammedupfromtoomuchloadorranemptywhenbinsdrained



early.Efficiencywasthusdifficulttomaintain.Safetywasalsoaproblemasworkersoftenhadtoenterstoragebinstochecklevelsortorepairjammedequipment.

Theimplementationofultrasonicmeasurementhasgreatlyimprovedoperationalefficiencyandsafetyinmining.Thenon-contactingtechnologyallowsforinventoryandprocessmanagementfromthesafetyofacontrolbooth.Crushersandfeedbeltsoperatewithoutinterruptionandloadsareaccuratelyandefficientlyprocessed.Ultrasoniclevelmeasurementoperatesinvariouslocationsthroughoutmining.Someofthem,liketheprimaryandsecondarycrushers,areidenticaltothoseusedinthecementindustry.Otherapplications,asshownintheprocessdiagrambelow,requiretheuseofultrasoniclevelequipmentforprocesscontrolandinventorymanagement.







CrusherOrelevelsinsurgebinsaremeasuredbyultrasonicsystemstomonitorthefeedintoacrusher.Thetransducers,althoughruggedindustrialdevices,mustbemountedfarenoughawayfromthefeedtoreducerepeatedcollisionsfromtheoreitself.

Thecrusherreducestheoretoamuchfinerconsistencysoitcanbeaddedtoanotherprocess.

FineorebinsTheXPStransducerseriesareidealformeasuringfineorelevels,atypicallydustyenvironment.ThemultipointSITRANSLU10controllercanmonitorlevelinthebinsandcanbeprogrammedforpriorityscanningtomonitorbinsthatarefillingatahigherratethanstaticbins.



FlotationcellsTheflotationprocessusedinmineralprocessingbeginsbyinjectingafrothingagentintomineralslurry,thenitpumpsthematerialintoanagitatedopentankoranaeratedflotationcell.



Thevaluablemineralsclingtothefroth,whichisthenscrapedfromthetopoftheslurry,afterwhichthefrothingagentisremovedfromthemineral-richconcentrate.Theconcentratesaredewateredandthewasteisdiscardedastailings.Foranefficientextractionprocess,itisessentialtomonitortheleveloftheslurryandtheleveloffroth.

Duringtheflotationprocessboththeheightandthicknessofthefrothmustbecalculatedtodeterminethedosageoftheexpensivechemicalreagents.Accuracyisimportantasitsavesmoneybyusingonlytherequiredamountofreagentsandbyremovingthemaximumamountofmineralsfromthefroth.

TwotransducersorSITRANSProbeLUsaremountedovertheflotationcell.Thefirstmeasuresthelevelofthefroth;thesecondmeasuresthelevelofthepulp.Thepulplevelisdeterminedbyusingafloatball/targetplateassembly:thefloatballfloatsontopofthepulp,arodwithatargetplateisattachedtotheballandthetransducermonitorsthelevelofthetargetplate.Thelevelofthetargetplateisdirectlyproportionaltothelevelofthepulp.Thesignalsfromthetransducersaresenttoaprocesscontrolsystemwhichcalculatesthefroththicknessandcontrolsthedosageofthechemicalreagentsaccordingly.



ChemicalstorageManychemicalsareusedaspartofmineralprocessingandarestoredonsite.Ultrasonicsystemsareusedforinventorymonitoringofthesechemicals.Non-contactingmeasurementisidealforthistypeofinventorymonitoring,astheaggressivenatureofmanychemicalsmakecontactdangerousorimpossible.



Slurrytanks

Shortrangeultrasonictransducersareflange-mountedaboveslurrytankstomeasuretheamountofliquid.ThePVDFenclosuresprotectthetransducersfrommostchemicalsfoundinslurrytanks.

SumppumpwellsManysumpwellsataminingsitecanbemeasuredbyshortrangeultrasonictransducersformorereliableperformance,especiallywhencomparedtosimplefloatsorothercontactswitches.Themanagementofwater,whetheritbetocontrolfloodingoraspartoftherefinementprocess,iscrucialtothemineoperation.

Orestoragebinsorstockpiles



Oftenoreisstoredinbinsorstockpilesbetweenprimaryandsecondarycrushingstages.Ultrasonicsystemsmonitorlevelinthebinsorstockpiles.Thisapplicationissimilartothequarrystockpilingofmaterialusedforcementproduction.

DiskfiltersAftertheconcentratehaspassedfromtheflotationcellsandthethickeners,diskfiltersdewatertheconcentratebeforeitproceedstothesmelterprocessing.Ultrasonicsystemsmonitorthelevelwithinthefilters



andactivatealarmsifthefilteredcake(thedewateredconcentrate)backsup,thuspreventingaspill.

Applicationone:measuringlevelinflotationcellsOneoftheworld’sleadingproducersofcopperandmolybdenumoperatesacoppermineinthewesternUSA.Theoperationusesaseriesofconecrushersandballmillstoreducecopperoretoveryfineparticleswhicharepulped(mixedwithwater)tocreateaslurry.Smallamountsofspecialreagentsareadded,includingafrotherandacollectorchemicalthatcausesthecoppermineralstosticktothebubbles.Thismaterialispumpedtoaseriesoffrothflotationcellstoconcentratethecopperwhereairisblownintotheflotationcelltank,andthepulpmixtureisvigorouslyagitatedlikeinahigh-speedblender.Risingbubblescarrythecopperparticlesupandovertheedgeoftheflotationtankwherethebubblesbreaksoonaftertheyflowovertheedge.Thecopperisthengroundevenfinerandpurifiedbyadditionalflotationprocesses.

Conditions

needtomeasurethelevelofboththepulpandthefrothtoensureoptimumcopperconcentrateproduction.Thoselevelsprovidefeedbacktotheplant’sprocesscontrolsystemsooperatorscanmakeappropriatechangestovariableslikepulpandairflowaswellastheadditionofchemicalreagents



difficultforlevelmeasurementbecauseofmaterialbuild-upandpluggingthatoccursonmosttypesofleveltechnologiesnarrowmeasurementrequirements:spanforthepulpmeasurement(usingtheProbeLUwithtargetandfloatassembly)is25.5centimeters(10")andthefrothlevelProbeusesaspanofonlyfivecentimeters(2")harshconditionsrequireaveryrobustdevice

SolutionTheSITRANSProbeLUultrasoniclevelmonitorcombinessensorandelectronicsinasinglepackageforeffectiveliquidlevelmeasurementinopenorclosedvessels.ThepatentedSonicIntelligenceecho-processingfiltersoutfalseechoesfromacousticalorelectricalnoisesandagitatorbladesinmotion,givingsuperiormeasurementreliability.

EachflotationcellisequippedwithaProbeLUtomonitorthefrothlevelwhileasecondProbeLUmeasuresthepulplevelbasedonametaltargetattachedtoamechanicalfloatassembly.The4to20mAanalogoutputfromtheProbeLUfeedsflotationcelllevelinformationintotheplant’scontrolsystem.

BenefitsTheSITRANSProbeLUsareveryeasytoprogramandtheyrequirenomaintenance.Theonlysetuprequiredisprogrammingthespanfortheanalogoutputwhichisreadilyaccomplishedintheinstrumentshoporduringinstallation.



AggregateTheaggregateindustryissimilartocementandmininginthatitinvolvesmanyofthesameprocessesandmuchofthesamematerial.Thedifferenceisthatitoccupiesthemediumstage,andwhiletherearesomeprocessesinvolved(seediagram),muchoftherequirementisforinventorymanagementandtransfercontrol.Applicationsrequiringprimaryandsecondarycrushers,aswellasorestoragebinsorstockpiles,areverysimilar,ifnotidentical,totheapplicationsinthecementindustry.Others,likethetertiarycrusher,arethesameasthosefoundintheminingindustry.Therearesomeapplicationsuniquetotheaggregateindustry,andtheseareshownintheprocessdiagram.

Blendingsilosandstoragebunkers



Theselargebunkersstorethecrushedore.LongrangetransducerswithEasyAimersprovidemaximumperformance.Loadingisoftendonebytrippercars,unmanneddevicesthatmovealongatrackoverthebunkers.Thetrippercarspositionthemselvesoveremptybunkersandloadtheore.

Screeningstation



Atthescreeningstation,amultipointultrasonicleveldeviceliketheSITRANSLU10measurestheindividualinventoryofbinsbasedonmaterialsize.

SummaryUltrasoniclevelinstrumentsplayanimportantroleintheMining,Aggregate,andCement(MAC)industries.Therugged,non-contactingtechnologyiscost-effective,accurate,andreliable;andcanbeusedforprocesscontrol,inventorymanagement,andevenasdistancelocatorsforcraneoperators.

EnvironmentalTheenvironmentalindustryisthebiggestmarketforultrasonicsensors.Fromwater/wastewatersystemstocleanwatersystems,sensorsmeasureflow,runpumps,activatealarms,andcontroladditiveinventories.

Collectionsystem:liftstation/pumpstation/wetwellInmunicipalitiesandcitieswithwatertreatmentfacilities,anunderground,gravity-fedcollectionsystemtransportsrawsewagefromresidentialandindustrialuserstothesewagetreatmentplant.Pumpstations(aka:liftstations)aredistributedthroughoutthesysteminplaces



wheregravityneedsahelpinghand.Insidethepumpstation,sewageiscollectedinthewetwell,atransitionpointfromwhichitispumpedout,orlifted,untilitreachesthetreatmentfacility.











Ultrasonicsystemsmonitorandcontrolthelevelofsewagewithintheliftstation.Asyoucanseefromthephotosoftheinsideofaliftstation,therearemanyobstructionsinthewells–thenarrowbeamangleandthenon-contactingnatureofultrasonicsmakeitanidealtechnologyformonitoringwetwelllevels.

AdvancedfeaturesincorporatedintoSiemensMilltronicscontrollersprovidemorethansimplepumpcontrol.TheSITRANSLUT400canmonitorpumpruntime,pumpfaults,pumpstarts,androtatepumpstoeventhewearonthepumpsorwearonepumppreferentially.

TheLUT400hasuniquetimingfeaturesthatadduptogreatbenefits.PumpON/OFFsetpointscanbechangedautomaticallybasedonthetimeofday,avoidingpumpingduringpeakelectricitypriceperiodsandgeneratingenergysavings.TheLUT400realtimeclockcontrolallowspumpsetpointstoalteraccordingtothetimeofday.Inatypicalwetwellinstallation,thiscouldmeanpumpingoutthewellbeforepeakrateandthendeferringpumpinguntilaftertheexpensiveperiod.Penaltiesimposedbyelectricitysuppliersforusageduringpeakhourscanbeavoidedinmostinstances.

TheLUT400pumpcontrolandlevelmeasurementsystemprovidestheoptimumsolutiontomanagecollectionnetworks.Pumpstatusandpumpedvolumearemonitoredusingtheprimaryleveldevice.Digital



inputscapturesiteandpumpdataprovidingacompletelyintegratedsystem.

Pumpingstationsaredesignedtohandlespecificflowrates–establishedbypopulationserved–butdemographicchangesalterrequirementsovertimesodesignvolumecannotbeassumed.Pumpedvolumeprovidesrealtrendingdataforcollectionsystemefficiencymonitoring.

Itisimpossibletomaintaincompletelysealedpipeworkfrompumpingstationtotreatmentworks.Groundwaterinfiltrationisinevitable.Pumpedvolumemonitoringcanprovidenetworkinformationtodetermineinfiltrationlocations.

NetworkcapacitycanbeeffectivelyusedbymonitoringcollectionflowsandtransmittingdataviatelemetrytoaSCADAsystem.Thisallowseffectiveassetmanagementandhelpstodiagnosestructuralproblems.

Combinedseweroverflows(CSO)Combinedsewagesystemscollectindustrial,residential,andstorm(rainwater)inthesamesewernetwork.Undernormalconditions,allofthesewageispipedtothesewagetreatmentfacilityfortreatmentanddischargedbackintotheenvironment.However,duringstormconditions,flowsincreasedramaticallyduetorunoffandoverflowsoftenoccur.Whenthishappens,thesewageandrainwateroverflowsaredischargedwithouttreatmentintotheenvironment–stream,ponds,orrivers.Theseoverfloweventsmustbeloggedforregulatorycompliancewiththetime,amount,andlocationrecorded.Ultrasonicsystems,liketheLUT400,canmonitorCSOsandrecordoverflowswhichcanbeusedforregulatorycompliance.

StormwaterpondsInsomecaseswhereoverflowsoftenoccur,stormwaterretentionpondsareinstalledtocollectthesewageandrainwaterandpreventrunofftoneighboringstreams.Oncethestormhassubsided,thewaterispumped



backintothecollectionsystemfortreatment.Ultrasonicsystemsareinstalledtomonitorthelevelinthesepondsandalertuserstothepresenceofstormwaterandofpossibleoverfillingofthepond.

Wastewatertreatmentplant

MainliftstationThemainstationisalargeliftstationlocatedatthesewagetreatmentfacility–alltheremoteliftstationswithinacityeventuallypumptheirsewagetothiscentralstation.Thisapplicationissimilartotheremoteliftstation;however,thewetwellismuchlargerandtherearegenerallyfewerobstaclesorobstructions.Ultrasonicsystemsmonitorthelevelandcontrolthepumpsthatconveythesewageintotheplantaswellasthesewageholdingsandprocessesintheplantitself.

Overflow/stormtankThisoverflowtanklocatedatthesewagetreatmentfacilityprovidesthesamefunctionasstormwaterponds.Actingasholdingfacilities,theycollectthecombinedsewageandstormrainwaterwhenthetreatmentplantisworkingatitsmaximumcapacity.Oncetheincomingflowtotheplantdropsbelowmaximumcapacity,theoverflowispumpedintothetreatmentworksforprocessing.



Intakeflow(influentflume)Flowtothefacilityneedstobemonitoredandcontrolledtomaintainplantefficiency.Ifinletflowexceedstheratedcapacity,itisdivertedtostormholdingtanks(seeabove)andlaterpumpedbackthroughtheinletonceflowsreturntonormal.

InletflowisoftenmonitoredusinganopenchannelprimarymeasuringdevicelikeaflumeorweirandSITRANSLUT400,asecondarymeasuringdeviceprovidinghighaccuracylevelmeasurementusingultrasonictechnology.

Flowdatamustbeloggedtoensurethefollowing:

thatthetreatmentplantoperateswithintolerancescompliancereportingforlocalenvironmentalregulationsisaccurate

BarscreenInorganicdebrisandmaterialiskeptfromenteringthetreatmentplantbybarscreensplacedintheinletchannel.Abuildupofdebrisontheupstreamsidecausesareducedlevelonthedownstreamsideofthe



screen.Whenenoughdebrisaccumulates,arakeisactivatedtoclearthescreenandmaintainflow.Thedebrisismaceratedanddriedbeforedisposal.

ASiemensHydroRanger200usestwoultrasonictransducerslocatedateithersideofthescreentomeasuretheupstreamanddownstreamlevels.ArelayonboardtheHydroRanger200activatestherakeatauser-defineddifferentialleveltocleardebris.Theuseofnon-contactingultrasonictransducersensuresyearsofmaintenancefreeoperation.

Solidslevelmeasurement



Sandanddebrisremovedbytherakeandgritchambersiscollectedinavessel(oragarbagedumpster)monitoredbyanultrasonicsystem.Oncefull,theultrasonicsystemprovidesanalarmtotheusersothatthevesselcanbereplacedwithanemptyone.

ChemicaltanksChemicals,likethealumusedasaflocculentinclarifiersorthechlorinethatdisinfectsthewaterbeforefinaldischarge,arestoredon-sitefordailyuse.Ultrasonicsystemsmonitorthelevelinthesevesselsforinventorypurposes.

Finaleffluent/dischargeflow



Alltreatmentplantdischargestotheenvironmentmustconformtodistrictlegislationregardingquantityandquality,soaccuracyiscriticalatthisstage.Primarydevicessuchasweirsorflumesthroughwhichtheflowischanneledprovidehighaccuracymeasurementandareoftenused.Thequalityofthedischargemustbemonitoredandistypicallydonewithasampler.

Toachieveaccurateflowmonitoringandcomplywithlegislationrequirements,aprimarymeasuringdevicecombinedwiththeLUT400openchannelmonitorcanbeused.TheLUT400convertshighaccuracyultrasoniclevelmeasurementtoaflowvalueusingknownheadversusflowformulaorBritishandISOStandards.Fulldataloggingcapabilitiesareavailabletologdailyflowtotalsandflowrates.

SludgetreatmentThesludgethatisleftafterthewaterhasbeenremovedisatoxicsoupofwasteproductsthatmustbetreatedverycarefully.Itshandlingishighlyregulatedandallprocessesarecarefullyscrutinized.Measurementofinventorythusplaysanimportantroleinsludgemanagement.

Digestergas



Biogases(methane)fromthedigesterareoftenstoredinagasholderwitha“floating”roof.Thesegasesarere-usedtoprovideheatingfortheplantorforlocalpowergeneration.Ultrasonicsystemsareappliedtomonitortheheightoftheroofandthustheamountofgaspresent.

DigesterlevelThisapplicationwasoftendonewithultrasonicswithlimitedaccuracyduetheeffectsofmethaneonthespeedofsound.Currently,radardevicesliketheSITRANSLR200andProbeLRprovideamoreaccurate,cost-effectivereadingandarereplacingultrasonicsasthefirstchoicetechnologyforthisapplication.

Dewatering/vacuumfilterThelevelofsludgeinthevacuumfilterismonitoredbyultrasonicsandcontrolsapumpthatwillcallformoresludgetothefilterfromthesludgetankwhenthelevelistoolow.



Environmentalapplications

Applicationone:liftstationcontrolAmunicipaldistrictinEuropeneededtoupgradeitswatertreatmentsystemandturnedtoSiemenstorenewthelocalmeasurementdevices,andcontrolequipmentandautomationsystem.Theyalsowantedtoincreaseremotemonitoringcapacity.

ConditionsTheprojectneededtointegrateexistinglevelmeasurementsolutionssuchashydrostaticpressuresensorswithanewultrasoniclevelmeasurementsystems,liftpumpcontrolmonitoring,anddataacquisition.

116pumpingstations18associatedcommunitiespopulationof140,000

SolutionSiemensinstalledthefollowingsystem:



SITRANSLUT400–thehighlyaccurateultrasoniccontrollerfromSiemenswaschosenforthepumpstationmonitoringandequipmentcontrol.EchomaxXRS-5ultrasonictransducerswereinstalledtomeasurelevel.

WithpatentedSonicIntelligenceecho-processingtechniques,theLUT400monitorsandcontrolsliquidlevelsinwellsand/orliquidflowinflumes,weirs,oropenchannels.ItsthreerelayscontrolalarmsorpumpsThesystemmonitorsliftstationsandcollectsdatasuchasstateofoperationandpumpruntime.Ateachliftstation,anLUT400controllerprocessessignalsreceivedfromlevelmeasurementtransducers.

DataistransmittedvialandlineusingSITRANSRD500tothecontrolroomatthedistrictheadoffice.TheSITRANSRD500hasabuilt-inwebserver,FTP,andemailclientwhichallowstheprocesstobemonitoredremotely.AlarmnotificationsarecommunicatedthroughemailandSMStextmessagestooneormorerecipientstoensurethatappropriateactionsaretakenbypersonnel.

BenefitsTheSITRANSLUT400provedareliableandcost-effectivesolutionforpumpcontrol,requiringlessmaintenancethanthepressuresensors.SITRANSLUT400increasedefficiencyandreducedmaintenancecosts.

InstallingSITRANSLUT400alsooptimizedspaceintheelectricalcabinetbyrationalizingcomponentsandreducingwiringtimes.ExistingequipmentwaseasilyintegratedwithLUT400andithooksseamlesslyintothecentralcontrolsystem.

Applicationtwo:wastewaterplantcontrolAmajorCanadiancitywithapopulationexceeding300,000neededtoupgradeitswastewaterplantsandpumpstations.

Allthelocationsweretolinkintoanewhigh-speeddatacommunicationsnetwork,integratingthemintoaSCADAsystem.Toensureaccuratedatagathering,thecityrequiredreliablefieldinstrumentsthatcouldintegrate



intothenetwork.Afterconductingaseriesofrigoroustestsonultrasonicleveltechnologiesfromseveralsuppliers,thecitychoseSITRANSLUT400withitsonemillimeteraccuracyandSiemensreliability.

Conditions

sixwastewatertreatmentplantshandlingatotalof208millionliters(55milliongallons)perdaythirty-eightpumpingstationswithcapacitiesrangingfrom0.75–21millionliters(0.2millionto21milliongallons)perday.twenty-fiveofthe38areduplexpumpingstations;therestarecomplexpumpingstationswithhugevariablefrequencydrive(VFD)pumps

SolutionSiemensinstalledtheLUT400inthe25duplexpumpingstationsforcontinuouslevelmonitoringandpumpcontrolandputSiemensEchomaxtransducers©2intothewetwells.

TheuniquepanelmountdesignoftheSITRANSLUT400madeforquickinstallation,andforeasyaccess.ThecontrollerswerenetworkedintoaPROFIBUScommunicationsystem.TheSCADAsystemreceivesinformationfromallstations,aswellasotherplantinformation,onthenetwork.AtthemorecomplexpumpingstationsemployingVFDpumps,theLUT400measureslevel,andtheanalogoutputisfedintoaPLCforpumpcontrolandremotetelemetry.



BenefitsTheultrasonicsystemsperformreliably,anddatacollectionfromthemanysitesisnowfastandaccurate.Operatorscanmonitorandcontroltheplantsitesfromthecentrallocation.Theautomatedsystemismoreefficient,andhasgeneratedsavingsinenergyandmaintenancecosts.StandardizingonLUT400simplifiedinstallationandtraining,savingstafftimeandmoney.

Applicationthree:smallcityoperatesatahighlevelAsmallbutgrowingCanadiancityneededtoincreaseitsfreshwateroutputduetoasteadilygrowingpopulation.Thisneedwascombinedwitharequirementtocontrolcostsandimproveefficiency,allthewhileimplementingnewregulationsrequiringenhancedsafety,training,andenvironmentalprotection.

Conditions

Populationof74,000andgrowingThesystembringswaterfromariver,cleansandtreatsit,thendistributesittoresidentsApproximately400kilometers(250miles)ofwatermainsPumpsanaverageof45millionliters(12millionUSgallons)ofwateraday

SolutionThewaterplantembracesfullyautomatedoperations.AllprocesspointsareintegratedfullyintoacentralSCADAsystemforcontinuousmonitoringandcontrol.Levelmonitoringisacriticalneedforawaterplant,andSiemensinstalledmorethan40pointsoflevelinthemainplantovertheyears.Theymonitortheriverlevel,gatepositionintheriver,aswellaslevelintheflocculationtanks,sedimentationbasins,settledwatertrough,filterbeds,finishedwaterstoragereservoirs,chemicaltanks,andotherapplications.Anultrasonicdevicemonitorsthefloorasasafeguardtodetectanyspillagefromaleakorrupturedpipe.



Atthecity’svariousstations,reservoirs,andelevatedwatertanks,thereareanother20pointsoflevelbeingconstantlymonitored.Signalsfromremotesitesaretransmittedbyradiolinktotheplantcontrolcenter.

BenefitsTheaccurateandresponsiveSiemenssensorsconstantlymonitortheriverrateofchange,acriticalmeasurement.Theyalsoprovedtheirpreventativevaluewhenoneoftheinteriortanksdevelopedaleakandanalarmwasimmediatelytriggered,preventingaseriousproblem.BecauseSiemenshasbeenthevendorofchoiceforquitesometime,theplantactuallyhasanumberofolderinstrumentmodelsoperating.Theseinstrumentsstillperformreliablyandaccurately,keepingmaintenancecostsdown.TheplantoperatorscreditSiemensultrasonicsystemswithhelpingthemintheireffortstodeliverqualitywaterefficientlytocityresidents.

Applicationfour:protectingwaterqualityAUKwatercompanyoperatesalargesubmergedmicrofiltrationplantthatservicesanentirecitywithpotablewater:

Theplantcapacityis84megalitresadaySixfiltrationcellsthatremoveparticlesassmallas0.2microns,includingbacteria,algae,andmicroorganisms.

ConditionsTwotypesoflevelmonitoringisrequired:



monitoringwaterlevelsiscrucialbecausethefltersrequireperiodicbackwashingwithfiltrateandair,andwithchemicalswhenthemaximumtransmembranepressureisreached.Afilterblockagemakesthewaterlevelrise,signalingtheneedforabackwash.monitoringthelevelsofthechemicalsonsite,includingsodiumhypochlorite,sulphuricacid,sodiumbisulphate,andsodiumhydroxide(causticsoda).Reliablelevelmeasurementofthechemicalstoragetanksiscrucialtosuccessfulprocesscontrol,inventorymanagement,andoverflowprevention.Levelsmustalsobemeasuredintheclean-in-placetank(CIP)andthewashwatertank.

Solution

SiemensEchomaxXRS-5ultrasonictransducersareinstalledona“tophat”sectionofeachchemicaltankusingaflangemounting.Thesetransducersarehermeticallysealedinchemicallyresistantenclosuresforreliableoperationinharshenvironmentsorchemicalapplications.ThetransducersarewiredtotheSITRANSLUT400controllerswhichfeedthe4to20mAoutputdirectlyintotheSCADAcontrolsystem.

Operatorscannoweffectivelymonitorthelevelineachofthestoragetanks.Theultrasonicsystemsworkeffectivelywithoutthecomplexityofhigherpricedsolutionsandwithouttheproblemsofcontactingandmechanicaldevices.PatentedSonicIntelligenceadvancedecho-processingtechnologyisbuilt-intoprovidesuperiorreliability.

Benefits



Non-contactingultrasonictechnologyrequiresalmostnomaintenance,andeliminatesworriesaboutchemicalcompatibility.Thereisnodriftfrommechanicalwear,andtheyarenotaffectedbydensitychangessothereisnoneedforrecalibration.

Theyareeasytoinstallandreplace,withnoneedtodrainthetank.Topmountingeliminatestheneedforisolationvalvesrequiredforside-mountedpressuretransmitters.

FoodindustryLikemanyotherindustries,foodapplicationscanbedividedintotwotypes,storageandprocess.Furthermore,storagecanbedividedintosolidsandliquids.Theseapplicationsarequitedifferentandeachpresentsitsownunique,butnotinsurmountable,challengesforlevelmeasurement.Forexample,a30meter(100ft)silofullofcornstarchisverydifferentthana1.5meter(5ft)stainlesssteelcookervesselfullofspaghettisauce.

SolidsSolidstorageapplicationsarecommon;mostfoodfactoriesneedtostorealargesupplyofrawmaterials.Cerealmillingcompanies,grainshipping,petfood,andbreweriesstorerawgrains(wheat,corn/maize,barley)inlargetallsilosorconcretebunkers;anXPS-30mountedwithanEasyAimerIImeasuringgrainatabrewingcompanyisshownhere.



Generally,longerrangetransducersareusedastheapplicationsareusuallygreaterthan15meters(50ft)andtheextrapoweroflongrangetransducersovercomesattenuationduetodust(evenondustyapplicationsthatmaybelessthan15meters(50ft)).EasyAimersarerecommendsothetransducersaremountedperpendiculartothematerialsurfacesthatoftenhaveasteepangleofrepose.Onexcessivelydustyapplications,theSITRANSLR560radaristherecommendedinstrument.

Often,manyofthesametypeofvesselsarefoundtogether,acerealmanufacturerstoringalargeinventoryofgrain,forexample,anditisbeneficialtouseamulti-pointsystemliketheten-pointSITRANSLU10tomeasureinventoryoftenvesselswithonecontroller.

SanitaryconnectionFoodprocessingvessels,whetherblendingfruitjuices,cookingsauces,ormixingicecreamflavours,aremuchsmaller,aremadeofstainlesssteel,andarecleanedregularly.Asanitarymountingprocessconnectionisrequiredtoensurecleanliness.TheProbeleveltransmitterandtheXCT-8transducerareavailablewitha4-inchsanitaryclampstyleprocessconnection.

Temperature



Thetransducerhastobeabletowithstandthecleaningtemperaturesduringthesanitizingprocess.Inmostcasesthetemperatureisintherangeof80°Candamildcausticsolutionissprayedontheinsideofthetank.Iftheleveldevicecannotwithstandthecleaningtemperaturethenitmustberemovedandsanitizedseparately;ifthecleaningtemperatureiswithintherangeofthetransducerthenitcanbecleanedinplace(oftenreferredtoasCIP).

ObstaclesTheinsideofaprocesstankhasnumerousobstaclesthatthelevelsystemhastotakeintoaccount.Theroundballisacleaningballandthesanitizingsolutionissprayedintothetankfromthisball.Whenmountingatransduceronafoodprocessvessel,makesurethatthecleaningballisnotwithinthebeampath.

LiquidsLiquidstoragevesselsarethemoststraightforwardmeasurementsforultrasonicsystemsinthefoodindustry.Thevesselsaregenerallylessthanfivemeters(16.5ft)inheightandhavelittleornoagitation.Theycontainfoodoils(vegetableoils),sugarsyrups(glucose,molasses),cleaningsolutions,water,acids,orfats.

Chemicalindustry



Applicationswiththechemicalindustryaregenerallylimitedtorawmaterialstoragevesselsorfinishedgoodsstorage–theprocess/reactorvesselsareusuallytoohotortoohighpressureforultrasonictechnology.However,otherancillaryapplicationsinthechemicalindustryrequireultrasonictechnology.Forexample,thesemaybethevesselsstoringlubeoilsforon-sitemachinerymaintenanceorcontainingthepre-treatmentwastewaterbeforeflowingitintothemunicipalwastewatertreatmentsystem.

Storagevesselsaretypicallybulkstorageofliquidchemicals,hydrochloricacid,orsulfuricacid.Storedinvesselstenmeters(33ft)orless,theypresentnochallengestotheultrasonicsystemotherthanrequiringthatthewettedmaterialofthetransducerhousingiscompatiblewiththematerialinthevessel.

Ultrasonicsisalsousedforinventorycontrolonfinishedgoodsstoragesilos.Apopularapplicationisthecontainmentofplasticpelletsinsilos.TheSITRANSLR560isalsoverysuitableforthisapplication.

Thesilosaretallandnarrowandthepelletsarepneumaticallyfed.Aimingisrequiredbecausethepelletshaveaslightangleofreposeandproperaimingincreasesthereceivedechostrengthandprovidesamorereliablesignal.

Applicationone:monitoringfluidlevelofdrillingmudpitsandtanksAsupplierofcontrolandinformationsystemsforhighqualityoilandgasdrillingequipmentwaslookingforatechnologytomonitorfluidlevelsindrillingrigmudpitsortanks.Drillingmudisanessentialcomponentindrilling,andprecisemonitoringofthetotalmudvolumeinarig’sdrillingfluidcirculatingsystemisessentialforsafe,efficientoperation.Varioustechnologies,includingmechanicalfloats,hadfailed.



Drillingfluidor“mud”ispumpeddownthroughthedrillpipewhereitblowsoutthroughnozzlesinthedrillbit.Themudthenflowsbackuptheholetothesurface,clearingtheholebycarryingtheformationcuttingsalongwithit.Themudlubricatesthedrillpipeandcoolsthedrillbit.Theweightofthemudcolumnpreventsformationfluidsfromenteringthewellbore,preventinga“blowout.”Throughhydrostaticpressure,italsohelpspreventcaving.Anincreaseinfluidlevelsmayindicategas,oil,orotherfluidshaveenteredthewellbore.Ifdrillingfluidlevelsdecrease,circulationisbeinglosttotheformation.Leftunchecked,eithersituationcouldresultinablowout.

Conditions

Mudtanksaregenerallysquareorrectangularinterconnectedsteeltanksusedonoffshoreoilrigstocontainthelargevolumesofdrillingmudflowingthroughthedrillingfluidcirculatingsystem.Onlandrigs,thesetanksarecalledmudpits,athrowbacktothedayswhenearthenpitsweredugtocontaindrillingmud.

SolutionThecompanyinstalledSITRANSProbeLUs.Thenon-contactingultrasonictechnologydoesnotbecomefouledwithmaterialnoraretheremovingpartstowearout,makingitpracticallymaintenancefree.TheProbeLU’sadvancedechoprocessingignoresmovingagitatorbladesandlocksontothetargetedmateriallevelinsteadofobstructions.Withits2-inchNPTconnection,itissimpletomount.Itcanbeinstalledandcalibratedregardlessofmateriallevelswithinavessel.Oneunitworkswithallvesselsizes.Itsrangegoesfromlessthan30centimeters(oneft)tomorethanfivemeters(16ft).ThereisanIntrinsicallySafeversionavailableforFMClassI,Division1applications.

BenefitsThecompanynowhasareliablenon-contactlevelmeasurement,avoidingelectromechanicaldevicesthataresubjecttowearandtear.Thesavingsfromreducedmaintenanceorreplacementcostsaresignificant.



Bothsafetyanddrillingefficiencyarealsoincreasedasthecompanyprovidesprecisemonitoringofacriticaldrillingvariable.

Applicationtwo:inventorycontrolOneofthelargestby-productsrecoveryfirmsinNorthAmericaneededtomeasurelevelintheirholdingtanks.Thetanks,indoorandoutdoor,holdavarietyofchemicalandoilwasteproductsreadyfortreatment.Governmentenvironmentalregulationsinsuchafacilityarenecessarilyverystringent.

BeforecontactingSiemens,thecompanyusedfloatswithexternalsightboardindicators.Thesemechanismsoftenstuckorfroze,andthemalfunctionsmademeasurementunreliable.Plantpersonnelhadtoconductfrequentvisualcheckstoverifythatthereadingswereaccurate,andtodetectandfixequipmentproblems.Unreliablereadingsalsomadeinventorymanagementproblematic.

Conditions

Outdoortanksfortreatingandstoringsolvents,wasteoils,andcausticsIndoortanksforhazardousprocesswaterMandatoryhigh-levelalarmstoguardagainstspills

SolutionSiemensinstalledacompleteultrasoniclevelmeasurementsystemthatoffersbothcontinuouslevelmonitoringaswellashigh-pointleveldetection.Eachofthe19tanksisequippedwithanEchomaxultrasonictransducer,connectedtooneofthreeSITRANSLU10transceivers.ThesystemusespatentedSonicIntelligencesoftwareforenhancedreliability.LeveldataisfedtoanHMI(Human-MachineInterface)locatedinsidethetestinglab.ASmartLinxinterfacecardconvertsthesignalstoModbusRTUprotocolusedbytheHMI.MaterialleveldataisroutedtothreeSAM-20devicesthatcontrolthehigh-levelalarmindicators,identifythetanks,andconnecttoaPLCthattriggersbothlightandsoundalarmsifhighlevelsoccur.



BenefitsWithautomated,reliablelevelmeasurementinplace,personnelnolongerneedtowastetimewithfrequentmanualinspections.Non-contactingultrasonictechnologyrequiresalmostnomaintenanceand,withnomorefloatmechanicalproblems,thecompanyhasgreatlyreduceditsmaintenancecosts.

Tanklevelsaremonitoreddirectlyinrealtime.Withexactcontentandstoragedataalwaysavailableattheclickofabutton,thelabcanscheduledeliveriesknowingstoragespaceisavailable.Reliablecontinuousmonitoringallowsforeffectiveschedulingandaccurateinventorycontrol.Thehigh-pointlevelalarmseliminatetheriskofspillage,andhelpenhanceplantsafety.

Otherindustries

Applicationone:ultrasonicsystemforPeterboroughLiftLockThePeterboroughLiftLockNationalHistoricSiteofCanadaisoneof40locksontheTrent-SevernWaterway,anationalhistoriccanaloperatedbyParksCanada.



Originallybuiltformarinecommerce,thewaterwaystretches386kmfromLakeOntario’sBayofQuintetoGeorgianBay.Today,itisaworld-famoustouristdestinationforrecreationalboatersandisregardedasoneofthefinestinterconnectedsystemsofnavigationintheworld.ThehistoriclockstationsoftheTrent-Severnarecentraltonumeroustownsandvillagesinthewaterwaycorridor.ThePeterboroughLiftLock(150kmnortheastofToronto,Canada)istheworld’shighesthydraulicliftlockandanengineeringmarvelthatattracts160,000visitorsannually.

ConditionsTheLiftLockisamassiveconcretestructuresupportingtwochamberswithramsconnectedinaclosedwaterhydraulicsystemwithacrossovervalve.Operatorsfloodtheupperchamberwithanextra30centimeters(12")ofwater,thenopenthecrossovervalvesothattheheavyupperchamberpushesdown,forcingthelowerchamberup.Boatsinthechambersareliftedorloweredabreathtaking19.8m(65ft)inonlyminutes.Smoothoperationdependsonensuringadifferentialof30centimetersofwater.Theweightdifferentialoftheextrawaterintheupperchamberdrivesthesystemthatraisesandlowersboats.

Throughoutitshistory,theLiftLockhasreliedonmanualwaterlevelmeasurementbut,whentheLiftLockcelebratedits100thanniversaryinJuly2004,itreceivedahightechbirthdaypresentfromSiemens



Milltronicswhoprovidedanewultrasoniclevelmeasurementsystem.“ThelevelmeasurementsystemisourbirthdaypresenttotheLiftLockasitturns100andourgifttothecommunityasSiemensMilltronicscelebratesits50thanniversarythisyear,”saidDaveBignell,PresidentandCEOofSiemensMilltronicsin2004.“We’reproudtohaveourtechnologyinstalledinthislandmarkstructure.”

SolutionEchomaxXRS-5transducersarenowmountedupstreamanddownstreaminABStubesandenclosedinaluminumpipe.Thisprotectstheultrasonicdevicesfrombeingbumpedordamagedbyboatsinthelock.ThetransducersarewiredintoaMultiRangertransceiverlocatedinthecontroltoweranditprocessesthesignalsandprovidesadigitalreadoutofthewaterlevels.MultiRangerisknownforitsreliable,accuratecontinuouslevelmeasurement.It’salsocompact,whichisimportantinthetightquartersoftheLiftLock’ssmallcontroltower.

Benefits“Thenewsystemhelpsensureproperoperationofthelock,”saysBruceKitchen,WaterControlEngineerfortheTrent-SevernWaterway.“Theultrasoniclevelsystemenablesthelockmastertotellataglancetheelevationsofthewaterupstreamanddownstream.Accuratelymonitoringandcoordinatingtheselevelshelpourstaffachievetheoptimumelevationdifferentialfortheworkingofthisheritagemachine.”

1BillyJoel,“RunningonIce.”TheBridge,1986.2©Copyright2004SiemensMilltronicsProcessInstruments.EchomaxandSITRANSLUT400areregisteredtrademarksofSiemensMilltronicsProcessInstruments.



ChapterSeven

Bestinclass–theultrasonicproductlineYou’resimplythebest,betterthanalltherest.1

TheSiemensMilltronicslineofsophisticatedultrasonicinstrumentsisdesignedtomeetlevelmeasurementchallengeswithaccuracy,reliability,andlongevity.Theinstrumentsrepresenttheexperiencegatheredfromanexcessofamillionapplications2andreflectthecollecteddedicationandinnovationofoverahalfacenturyofservicebyourenthusiasticandimaginativepeople.

Fromtransistorstochips,frommilliampstoPROFIBUS,frommetaltoPVDF,fromaconvertedgaragetoamultinationalcompany,SiemensMilltronicshaspushedtheboundariesofultrasonictechnologytotakealeadershiproleinthewater/wastewaterindustryonaglobalscale.

Ourultrasonicinstrumentsmeetthechallengeofmanytypesofapplications,andtheSiemensMilltronicscatalogcontainsinstrumentsforthemall.Inthefollowingpages,weofferbriefdescriptionsofbothourlatestandgreatest,aswellasthetriedandtrue.Combined,theyformagroupreadytotakeonthemeasurementchallenge,atanylevel.

SITRANSLUT400SITRANSLUT400isahighaccuracysystemthatexcelsatcontinuouslevelmonitoringandcontrolinliquid,solid,orslurryapplicationsinawiderangeofindustries.



Threemodelsmakeuptheseries:

SITRANSLUT420LevelControllerSITRANSLUT430Level,Pump,andFlowControllerSITRANSLUT440HighAccuracyOpenChannelMonitor(OCM),whichalsoprovidesafullsuiteofadvancedlevel,volume,andpumpcontrols

Thesecontrollersareaflexiblesolutionforaworldofapplications:water/wastewatermonitoringandpumping,inventorymanagement,crushercontrol,truckload-outs,oranythinginbetween.

Thesystemiseffectiveinwetwells,weirs,andflumeswherebuildupandturbulencearetypicaloperatingconditions.Itcanbecustomizedtomeetyourspecificapplicationneeds—frommeasuringflowrateinanarrowflumetovolumeinaferricchloridestoragebank.

Inadditiontomonitoringflowrateinsewageworks,SITRANSLUT400canmonitorindustrialdischargeandproviderainfall/stormwaterstudies,inflow/infiltrationstudies,andsewersystemevaluations.Theprogrammableheadversusflowcurveaccuratelydefinesflowrateonuniqueornon-standardweirsandflumes.

TheLUT400hasdataloggingandisadjustable,rangingfromonceperminutetoonceadayasitrecordstheaverageflowrateforthattimeperiod.Dailyrecordingincludesmin/maxoftemperatureandflowrates,



thetimetheyoccurred,andthedailytotal.Advancedfunctionsincludevariableratelogging.Itcanbepre-programmedtologatahigherratewhenneeded.

TheSITRANSLUT400featuresawall,pipe,orDINrailmountedenclosure,housingelectronicswithahermeticallysealed,corrosion-resistantEchomaxtransducer.Componentscanbeseparatedasfaras365meters(1200ft).

Keybenefitsindustry-leadingaccuracyof±1mm(0.04")givesyouconfidenceinyourmeasurementseasytouse–localuserinterfacewithfour-buttonprogramming,menu-drivenparameters,andWizardsupportforkeyapplicationsoptionalsubmergenceshieldstoprotectthetransducerduringflooding.Patenteddetectionsoftwarecandifferentiatebetweenasubmergedconditionandahighlevel.wall,pipe,andDINrailmountingconfigurationswith¼-turnfastenersforquickaccessandhassle-freewiringwithremovableterminalstripsoutputsforalarms,chartrecorders,controllers,andintegrationofexistingsystemsenergysavingfunctionswithbuilt-inreal-timeclockreal-timeclockcontrolallowspumpsetpointstoalteraccordingtothetimeofday.Inatypicalwetwellinstallation,thiscouldmeanpumpingoutthewellbeforepeakrateandthendeferringpumpingduringtheexpensiveperiod.Penaltiesimposedby‘triads’andsimilarelectriccompanyincentivescanbeavoidedautomaticallyinmostinstances.specialcontrolmodetoreducegreaseringsandotherdepositswithapumpvolumesystemusingpatentedalgorithms,theLUT400continuouslymonitorsinflowpriortoapumpstarting,thuscalculatinganaccurateandtimelyinflowrate.Wheneachpumpstarts,itscurrentcapacityiscalculatedandstored,givingaccuratecalculation



ofpumpedvolumethroughput,unaffectedbyvariableinflow.Theunitdoesnotrequireanydiscreteinputsfromthepumps,oranyformofin-lineflowmonitoring.

Keyapplications

wetwells

flumes/weirs

chemicalstorage

liquidstorage

bulksolidsstorage(gravel,flourbins,grains,cereals)

plasticpellets

crushercontrol

SITRANSProbeLUSITRANSProbeLUisa2-wirelooppoweredultrasonictransmitterforlevel,volume,andflowmonitoringofliquidsinstoragevessels,simpleprocessvessels,andinopenchannels.SITRANSProbeLUisdesignedtomonitorlevelinthewaterandwastewaterindustryandinchemicalstoragevessels.

SITRANSProbeLUfeaturesfield-provenSonicIntelligencesignalprocessingthatincorporatesnewechoprocessingcapabilitiesandthelatestmicro-processorandcommunicationstechnology,providingacontinuouslevelmeasurementrangeofeithersixortwelvemeters(20or40feet),dependingonapplicationrequirements.

SITRANSProbeLUoccupiesauniqueplaceintheultrasoniclandscape.WithitsAutoFalse-EchoSuppression,iteffectivelyeliminatesvesselobstructions,negatinganyinterferencecausedbyextraneousvessel



clutter.Furthermore,itsadvancedsignal-to-noiseratioallowsforclearechoesandamarket-leadingaccuracyfortransmittersof0.15%ofrange.

OtherapplicationconditionslikechemicalcontentsandprocesstemperaturevariationsareeasilydealtwithbecausethetransducerisavailableasETFE3orPVDF4,andaninternaltemperaturesensorcompensatesfortemperaturechanges.

Keybenefitseasyinstallationandsimplestartupprogrammableusinginfraredintrinsically-safehandheldprogrammer,SIMATICPDM,orHART®CommunicatorcommunicationusingHARTorPROFIBUSPApatentedSonicIntelligencesignalprocessingextremelyhighsignal-to-noiseratioAutoFalse-EchoSuppressionforfixedobstructionavoidance

Keyapplications

Storagevessels Waterindustry

acid

lubeoils

juices

vegetableoils

resins

cleanwatertowers

liquidsugars/cornsyrup

fueloils

charcoalfilters

flocculants

stormwaterholdingtanks

chlorinestorage



Sulfuricacidstorage Waterstorage

TheProbeTheProbeisashort-rangeintegratedultrasonicleveltransmitter,idealforliquidsandslurriesinopenorclosedvessels.ThetransducerisavailableinPVDF,makingthedevicesuitableforuseinawidevarietyofapplicationsfromwater/wastewatertopizzasauce.Itisidealforthefoodandpharmaceuticalindustriesasitcanbequicklyremovedforcleaning.

TheProbeisaworkhorse,providingreliableleveldatabasedonSonicIntelligenceechoprocessingalgorithms.Ithasanonboardfilterthatdiscriminatesbetweentrueandfalseechoesfromacousticalorelectricalnoisesandagitatorbladesinmotion,aswellastemperaturecompensation.Italsoprovidesdistancereadingsconvertedfordisplay,analogoutput,andrelayactuation.

Keybenefitseasytoinstall,program,andmaintainaccurateandreliable



transducersavailableinPVDFsanitarymodelavailablepatentedSonicIntelligence®echo-processingintegraltemperaturecompensationuptofivemeter(16.5ft)measurementrange

Keyapplications

chemicalstoragevessels

filterbeds

mudpits

liquidstoragevessels

MultiRanger100/200MultiRangerisaversatile,shorttomedium-rangeultrasonicsingleandmulti-vessellevelcontroller.MultiRangerofferstruedual-pointmonitoring,digitalcommunicationswithbuilt-inModbus®RTUviaRS-485,aswellascompatibilitywithSIMATICPDM,allowingPCconfigurationandsetup.MultiRangercontainsSonicIntelligenceadvancedecho-processingsoftwareforincreasedreadingreliability.

MultiRangerfeaturesthefollowing:

cost-effectivelevelalarming



ON/OFFandalternatingpumpcontrolupto15meters(50ft)measuringrangemonitorsopenchannelflowconvertslevelreadingtovolumemeasuresdifferentialleveloverabarscreenadvancedrelayalarmingadvancedpumpcontrolfunctions

MultiRangeriscompatiblewithchemical-resistantEchomaxtransducersthatcanbeusedinhostileenvironmentsattemperaturesashighas145°C(293°F).

Keybenefitsdigitalinputforback-upleveloverridefrompointleveldevicecommunicationusingbuilt-inModbusRTUviaRS-485compatiblewithSmartLinxsystemandSIMATICPDMconfigurationsoftwaresingleordual-pointlevelmonitoringAutoFalse-EchoSuppressionforfixedobstructionavoidancedifferentialamplifiertransceiverforcommonmodenoisereductionandimprovedsignal-to-noiseratiowallandpanelmountingoptions

Keyapplications

water/wastewater

fueloil

municipalwaste

acids

woodchips

materialswithhighanglesofrepose

bulksolidsstorage



MultiRangermonitoringandstoragevessel

TwoMultiRangersmeasuringammoniatanks

MultiRangermeasuringcanallevelsatPeterboroughLiftLock,Ontario,Canada

SITRANSLU10SITRANSLU10isalong-rangelevelmonitoringsystemforliquidsandsolids,offeringten-pointmonitoringinasingleunitforawiderangeofapplicationstoscanliquids,solids,oracombinationofbothcontainedinvesselsofdifferingsizes,shapes,andconfigurations.



UsingthepatentedSonicIntelligenceecho-processingsoftwaretomeasurelevel,space,distance,volume,oraverage/differential,theLU10providessuperiorreliabilityandaccuratemeasurementinvesselsupto60metersinheight(200ft).Furthermore,transducerscanbemountedupto365meters(1200ft)fromthemonitor.Readingsaredisplayedinuser-selectablelinearengineeringunitsonthebacklitLCD.

KeybenefitsconnectiontoaDCSorPLCusingSiemensMilltronicsSmart-Linx®interfacemodulesforremotetwo-waycommunicationandfullparameteraccess5ten-point,long-rangelevelmonitoringautomaticlevel-to-volumeconversionforstandardorcustomtankshapesDolphinPluscompatibleeasytoinstall,easytoprogramwithremovableinfraredkeypadtenmAoutputsareavailablethroughexternalmoduleSITRANSLUAOtwentyrelaysforalarmsareavailablethroughexternalmoduleSITRANSLUSAM

Keyapplications



chemicalstorage

liquidstorage

bulksolidsstorage(sugar,flourbins,grains,cereals)

plasticpellets

tankfarms

SITRANSLU10monitoringcoalbunkers

HydroRanger200HydroRanger200isalevelcontrollerforuptosixpumps,andprovidescontrol,differentialcontrol,andopenchannelflowmonitoring.



Forwaterauthorities,municipalwater,andwastewaterplants,HydroRanger200isaneconomical,low-maintenancesolutiondeliveringcontrolefficiencyandproductivityneededtomeettoday’sexactingstandards.

HydroRanger200usesprovencontinuousultrasonicechorangingtechnologytomonitorwaterandwastewaterofanyconsistencyupto15meters(50ft)indepth.Achievableresolutionis0.1%withaccuracyto0.25%ofrange.Unlikecontactingdevices,HydroRanger200isimmunetoproblemscausedbysuspendedsolids,harshcorrosives,greaseorsiltintheeffluent,reducingdowntime.

Keybenefitssingleordual-pointmonitoringdigitalcommunicationswithbuilt-inModbusRTUviaRS-485SIMATICPDMcompatible,allowingforPCconfigurationandset-up.SonicIntelligenceadvancedecho-processingsoftwareprovidesincreasedreadingreliabilitywallorpanelmountingversions



sixrelaysonboardasstandardmonitorswetwells,weirs,andflumescompatiblewithSmartLinxsystemanti-greaseringfunctiondifferentialamplifiertransceiverforcommonmodenoiserejectionandimprovedsignal-to-noiseratioMCERTSapprovedforopenchannelflow

Keyapplications

wetwells flumes/weirs barscreencontrol

EchomaxTransducersEchomaxtransducersfireultrasonicpulsesandmeasurethereturnechoestodeterminethedistancefromthetransducertothematerial,whetheritbeawiderangeofliquidsorbulksolidsapplications.Designsareavailablewithdifferentmeasuringranges,processconnections,andambienttemperaturespecifications.Thetransducersaresuitableforuseinmanyapplicationsfromthebenigncleanwaterfacilitiestotheaggressivechemicalplantsordustygrainapplications.

Toselectthepropertransducerfortheapplication,chooseaccordingtoapplicationrequirementsthatincludedistance,temperature,andvesselconfiguration.Thechartbelowindicateswhichtransducersaresuitablefortheapplications.



XRS-5EchomaxXRS-5ultrasonictransducerprovidesreliable,continuousnon-contactinglevelmonitoringofliquidsandslurriesinnarrowliftstations/wetwells,flumes,weirs,andfilterbeds.Withabeamangleofjust10°andaCSMrubberface,ithasameasuringrangefrom0.3to8meters(1to26ft).Advancedechoprocessingensuresreliabledataeveninconditionswithobstructions,turbulence,andfoam.

Thepre-molded,hermeticallysealedrubberfaceandthePVDFenclosurearedesignedformaximumresistancetomethane,saltwater,caustics,andharshchemicalscommontowastewaterinstallations.With



anIP68degreeofprotection,thisruggedsensorisfullysubmersibleintheeventoffloodconditions.Iffullsubmergenceispossibleintheapplication,useasubmergenceshieldtomaintainahighlevelreadingoutputduringsubmergedconditions.

Keybenefitsbasicsystemforhigh/lowalarmordualpumpcontrollow-costtransducercompatiblewithafullrangeofSiemensMilltronicstransceiversconnectstoadvancedcontrolsystemswithcommunications,telemetry,andSCADAintegrationcapabilitieschemicallyresistantPVDFcopolymerenclosureandCSMrubberfacemeasuringrange:eightmetersformeasurementofliquidsandslurriesfullysubmersible:IP68degreeofprotectioneasyinstallationwith1"NPTor1"BSPconnection

Monitoringlevelinsewagewetwell

XPS/XCTSeries



EchomaxXPS/XCTtransducersmeasurelevelinawiderangeofliquidsandsolids.Thetransducerscanbefullyimmersed,areresistanttosteamandcorrosivechemicals,andcanbeinstalledwithoutflanges.

TheXPSseriesoffersversionsforvariousmeasuringrangesupto40meters(130ft),anduptoamaximumtemperatureof95°C(203°F).TwomodelshaveFMClass1,Div.1approvalsforapplicationswithameasuringrangeuptofifteenmeters(50ft).

TheXCTseriescanbeusedinapplicationsathighertemperaturestomeasureleveluptoadistanceoftwelvemeters(40ft)andatamaximumtemperatureof145°C(293°F).

Duringoperation,Echomaxtransducersemitacousticpulsesinanarrowbeam,sotheyareidealtransducersfordustyapplicationsandforthosewithalotofobstructions.

Keybenefitsintegraltemperaturecompensationlowringingeffectreducesblankingdistanceself-cleaningandlowmaintenanceconnectusingonlytwowires



XPS-15measuringaggregate XPS-30smeasuringminingsilos

chemicallyresistantPVDFenclosureCSA,FM,ATEXandotherglobalapprovalshermeticallysealed

XLTSeriesEchomaxXLTtransducersoperateinawiderangeofbulksolids.UsingaSiemensMilltronicscontroller,theymeasurefrom0.9to60meters(1.8to200ft)inconditiontemperaturesupto150°C(300°F).Abeamangleofjust5°providesaccuratereadingsindeep,narrowtanks.

Withitshighlydevelopedsignalsensitivity,theXLTtransduceroperatesinavarietyofdifficultapplicationsincludinglimestone,cementclinker,andhotstone.Allmodelshaveasealedaluminumfacetowithstandharshestenvironments,andtemperaturevariationsareautomaticallycompensatedforbytheintegraltemperaturesensor.

Keybenefitssealedaluminumfaceintegraltemperaturesensorself-cleaningandlowmaintenancetwo-wireconnection



easy-to-install1”threadedconnection

ST-HST-Htransducersmeasurelevelinchemicalstorageandliquidtanks.ThenarrowdesignoftheST-Hallowsthetransducertobemountedona2"standpipe.Whenmountedcorrectly,itiscompletelyprotectedfromtheprocess,andcanevenbeusedinharsh,corrosiveenvironments.

Keybenefitscanbemountedona2"standpipeimmunetocorrosiveandharshenvironmentseasytoinstallintegraltemperaturesensor

ST-Hmonitoringasmallammoniatank

Conclusion



TheSiemensMilltronicsultrasonicinstrumentsoffercustomersathoroughlevelmeasurementsolution,regardlessofapplication.Fromsmallfoodtankstoten-storeysilos,ultrasonicmeasurementisreliableandcost-effective.Itremainsavibrantmeasurementpartner,alongwithagrowingnumberoftechnologiesofferedbySiemens.Oncethecenteroftheindustry,itisnowjoinedbyradar,frequencybasedcapacitance,andTDRtoofferafullcomplementoflevelapplicationsolutions.LevelmeasurementinturnisanintegralcomponentoftheSiemensTotallyIntegratedSolutionsapproachtocustomerrequirementsforprocessinstruments,promotingaunifiedinstrumentationstrategy.Flowmeters,valvepositioners,temperaturetransmitters,pressuretransmitters,andgasanalyzersopenuppossibilitiesforapplicationsolutionsotherthanthoserequiringultrasoniclevelmeasurement.

ThisfullarmamentofinstrumentsandtechnologiesisthestrengthofwhatSiemenscanofferitscustomers,andultrasonicsbeatsstronglyatitscore.Thetechnologyhasbeenhardatworkforseveraldecadesandshowslittlesignoflosingitspopularity.Industrialdevelopmentslikedigitalcommunications,trending,datalogging,andsoftwareconfigurationpackageskeepitcurrentandviable,alongsidethewholeoftheinstrumentationcatalog.

SiemensMilltronicsisdeterminedtodevelopultrasonictechnologytoitsutmostcapacity,andrecentproductsliketheSITRANSLUT400illustratethedeploymentofthetechnologytoitsmaximumbenefitbycombiningthebestoftheoldwiththebestofthenew.

ThesimplicityandprecisionoftheSITRANSLUT400exemplifieshowultrasonictechnologyisstillaviableandvibrantplayerinthelevelmeasurementfield.Whileothertechnologieslikeradar,capacitance,andTDRhavetheirplace,ultrasonicsremainsacost-effectiveworkhorsethatoffersreliableandlongtermservice.Whencoupledwiththelatestadvancesincommunicationsandsoftwareconfiguration,ultrasonicinstrumentationremainsmadeofsternerstuffandasignificantplayeronthelevelmeasurementstage.

1TinaTurner,SimplytheBest.1989(originallydonebyBonnieTyler,1988).



2SiemensMilltronicshasinstalledoveramilliontotalapplications,combiningalltechnologies,includingultrasonics,radar,capacitance,andmechanicallevelmeasurement.Allofthisexpertiseisincorporatedineveryproductdesignedandproduced.3EthyleneTetrafluoroethylene4PolyvinylideneFlouride5Modulesforpopularindustrialbusescanbefactoryinstalledoraddedlatertomeetchangingneeds.Noexternalgatewayisrequired,reducinghardwareandcablingcosts.



GlossaryEntriesinthisglossaryarefromtheOperationofMunicipalWastewaterTreatmentPlantstextbook,fromtheIEEEdefinitionbook,andfromthecontributionsprovidedbySiemensMilltronicsProcessInstrumentsproductandapplicationspecialists.

A

Accuracy Theabsolutenearnesstothetruth.Inphysicalmeasurements,itisthedegreeofagreementbetweenthequantitymeasuredandtheactualquantity.

Aeration 1)Thebringingaboutofintimatecontactbetweenairandaliquidbyoneormoreofthefollowingmethods:a)sprayingtheliquidintheairb)bubblingairthroughtheliquidc)agitatingtheliquidtopromotesurfaceabsorptionofair.

2)Thesupplyingoftheairtoconfinedspacesundernappes,downstreamfromgatesinconduits,andsoon,torelievelowpressuresandtoreplenishairentrainedandremovedfromsuchconfinedspacesbyflowingwater.

3)Reliefoftheeffectsofcavitationbyadmittingairtotheaffectedsection.

AerationTank Atankinwhichwastewaterorotherliquidisaerated.

AerobicDigestion

Thebreakdownofsuspendedanddissolvedorganicmatterinthepresenceofdissolvedoxygen.Anextensionoftheactivated-sludgeprocess,wastesludgeisstoredinanaeratedtankwhereaerobicmicro-organismsbreakdownthematerial.

Agitator Mechanicalapparatusformixingoraerating.Adeviceforcreatingturbulence.

Algorithm Aprescribedsetofwell-definedrulesorprocessesforthesolutionofaprobleminafinitenumberofsteps.

Allen-Bradley®RIOorAB®Rio

Allen-BradleyRIOprotocolisanoldprotocolforcommunicatingtoremoteI/O.ItisonlyusedbyAllen-BradleyPLCs.

Alum,Aluminum

Usedasacoagulantinfiltration.Dissolvedinwater,ithydrolysesintoAl(OH)2Sulfateandsulfuricacid(H2SO4).Toprecipitatethehydroxide,asneededfor[Al2(SO4)3•18H2O]coagulation,thewatermustbealkaline.

Ambient Generallyreferstotheprevailingdynamicenvironmentalconditionsinagivenarea.

AmbientTemperature

Thetemperatureofthesurroundingairthatcomesincontactwiththeequipment.

AnaerobicDigestion

Thedegradationofconcentratedwastewatersolids,duringwhichanaerobicbacteriabreakdowntheorganicmaterialintoinertsolids,water,carbondioxide,andmethane.

AnalogSignal Asignalwherethevaluecanbeinarangeofvalues(example:from4mAto20mA).

Antenna Anaerialwhichsendsoutandreceivesasignalinaspecificdirection.Therearefourbasictypesofantennainradarlevelmeasurement.SeeHorn,Parabolic,Rod,andWaveguide.

Attenuation Atermusedtodenoteadecreaseinsignalmagnitudeintransmissionfromonepointtoanother.Attenuationmaybeexpressedasascalarratiooftheinputmagnitudetotheoutputmagnitudeorindecibels.

AutoFalse-Echo

Suppression

AtechniqueusedtoadjustthelevelofaTVTcurvetoavoidthereadingoffalseechoes.(SeeTVT).



AutoFalse-Echo

SuppressionDistance

DefinestheendpointoftheTVTdistance(SeeTVT).Thisisusedinconjunctionwithautofalse-echosuppression.

AutomaticSampling

Collectingofsamplesofprescribedvolumeoveradefinedtimeperiodbyanapparatusdesignedtooperateremotelywithoutdirectmanualcontrol.Seecompositesample.

AverageFlow Arithmeticaverageofflowsmeasuredatagivenpoint.

AverageVelocity

Theaveragevelocityofastreamflowinginachannelorconduitatagivencrosssectionorinagivenreach.Itisequaltothedischargedividedbythecross-sectionalareaofthesectionortheaveragecross-sectionalareaofthereach.Alsocalledmeanvelocity.

B

BarScreen Ascreencomposedofparallelbars,eitherverticalorinclined,placedinawaterwaytocatchdebris.Thescreeningsarerakedfromiteithermanuallyorautomatically.Alsocalledbarrack,rack.

BeamAngle Anglediametricallysubtendedbytheone-halfpowerlimits(-3dB)ofthesoundbeam.

BeamSpreading

Thedivergenceofabeamasittravelsthroughamedium.(http://www.ndt.net/article/az/ut_idx.htm)

Bias InSiemenslevelequipment,thereisaconfidencebiasvalueaddedindBtotheshortshotconfidencevalue.Thisisforcomparisononly.Itallowstheshortdistancetobechosenoverthelongshotdistancewiththesameconfidencevalue.PresetMilltronicsequipmentto20dB.

Biosolids Theorganicproductofmunicipalwastewatertreatmentthatcanbebeneficiallyused.

Blanking Zoneextendingdownwardfromthetransducerfaceinwhichitisreceived.

Bus Network.

BypassPipe Apipethatismountedperpendiculartoavesselwallandisopentothevesselatthetopandbottom.Thisistypicallyusedonvesselsthathavealotofturbulenceorfoam.Thebypasspipeprovidesacalmliquidsurfacelevelequaltothelevelinthevessel.

C

Cavitation 1)Theaction,resultingfromforcingaflowstreamtochangedirection,inwhichreducedinternalpressurecausesdissolvedgasestoexpand,creatingnegativepressure.Cavitationfrequentlycausespittingofthehydraulicstructureaffected.

2)Theformationofacavitybetweenthedownstreamsurfaceofamovingbody(forexample,thebladeofapropeller)andaliquidnormallyincontactwithit.

3)Describingtheactionofanoperatingcentrifugalpumpwhenitisattemptingtodischargemorewaterthansuctioncanprovide.

CentrifugalPump

Apumpconsistingofanimpellerfixedonarotatingshaftandenclosedinacasinghavinganinletandadischargeconnection.Therotatingimpellercreatespressureintheliquidbythevelocityderivedfromcentrifugalforce.

cfs(cuft./sec.) Therateofflowofamaterialincubicfeetpersecond;usedformeasurementofwater,wastewater,orgas;equals2.832x10-2m3/s.

Chlorination Theapplicationofchlorineorchlorinecompoundstowaterorwastewater,generallyforthepurposeofdisinfection,butfrequentlyforchemicaloxidationandodorcontrol.

Chlorinator Anymeteringdeviceusedtoaddchlorinetowaterorwastewater.



http://www.ndt.net/article/az/ut_idx.htm

ChlorineContact

Chamber

Adetentionbasinprovidedtodiffusechlorinethroughwaterorwastewaterandtoprovideadequatecontacttimefordisinfection.Alsocalledachlorinationchamberorchlorinationbasin.

Clarification Anyprocessorcombinationofprocesseswhoseprimarypurposeistoreducetheconcentrationofsuspendedmatterinaliquid;formerlyusedasasynonymforsettlingorsedimentation.Inrecentyears,thelattertermsarepreferablewhendescribingsettlingprocesses.

Clarifier Anylargecircularorrectangularsedimentationtankusedtoremovesettleablesolidsinwaterorwastewater.Aspecialtypeofclarifier,calledanupflowclarifier,usesflotationratherthansedimentationtoremovesolids.

CollectionSystem

Inwastewater,asystemofconduits,generallyundergroundpipes,thatreceivesandconveyssanitarywastewaterorstormwater;inwatersupply,asystemofconduitsorcanalsusedtocaptureawatersupplyandconveyittoacommonpoint.

CombinedSewer

Asewerintendedtoreceivebothwastewaterandstormorsurfacewater.

CONF. CONF.istheconfidenceofsignalvaluegeneratedbythecomputer.Itisbasedonalloftheechoprocessingalgorithms.ItcanbereadinRun(key#8)andprogrammodeP805.

Confidence Describesthequalityofanecho.Theechoconfidenceisbasedonhowwellthetransducerismountedandaimed,andthenoisefloorassociatedwiththeechoprofile.Transceiversdisplayboththeshortandlongechoconfidence.IfanechoisbelowaspecificconfidencethresholditisignoredbytheSonicIntelligence®softwareroutines.

ConfidenceThreshold

Thisistheminimumconfidencevalueofanechotoberecognizedasavalidecho(Parameter805).

D

DaisyChained Connectedinseries,oneaftertheother.Cableisconnectedtothefirstdevice,thencomesoutofthefirstdeviceandisconnectedtotheseconddeviceandsoon.

Damping Termappliedtotheperformanceofaninstrumenttodenotethemannerinwhichthemeasurementsettlestoitssteadyindicationafterachangeinthevalueofthelevel.

dB(decibel) Aunitusedtomeasurethelevelofsound.

Dechlorination Thepartialorcompletereductionofresidualchlorinebyanychemicalorphysicalprocess.Sulfurdioxideisfrequentlyusedforthispurpose.

Defoamer Amaterialhavinglowcompatibilitywithfoamandalowsurfacetension.Defoamersareusedtocontrol,prevent,ordestroyvarioustypesoffoam,themostwidelyusedbeingsiliconedefoamers.Adropletofsiliconedefoamercontactingabubbleoffoamwillcausethebubbletoundergoalocalanddrasticreductioninfilmstrength,therebybreakingthefilm.Unchanged,thedefoamercontinuestocontactotherbubbles,thusbreakingupthefoam.Avaluablepropertyofmostdefoamersistheireffectivenessinextremelylowconcentration.Inadditiontosilicones,defoamersforspecialpurposesarebasedonpolyamides,vegetableoils,andstearicacid.

DeviceDescription

AprogramfilewrittenintheHARTorPROFIBUSDeviceDescriptionLanguage

(DD) (DDL)thatcontainsanelectronicdescriptionofallofadevice’sparametersandfunctionsneededbyahostapplicationtocommunicatewiththedevice.

DeviceNetTM Aprotocoldevelopedbyagroupofcompaniesasanopenstandard,usedtoestablishmaster-slave/client-servercommunicationsbetweenintelligentdevices.ItisbasedontheCAN(ControlAreaNetwork)protocolandisdesignedforconnectingupintelligentdevicessuchaslimitswitchesandphoto-electricsensors.Seewww.odva.org.

Dewater Toextractaportionofthewaterpresentinasludgeorslurry.



http://www.odva.org

DifferentialFrequency

ThefrequencydeterminedbycalculatingthedifferencebetweenthetransmittedandreceivedfrequencyoftheFMCWradar.

DigestedSludge

Sludgedigestedundereitheraerobicoranaerobicconditionsuntilthevolatilecontenthasbeenreducedtothepointatwhichthesolidsarerelativelynonputrescibleandinoffensive.

Digester Atankorothervesselforthestorageandanaerobicoraerobicdecompositionoforganicmatterpresentinthesludge.SeealsoAerobicDigestion.

DigitalSignal Asignalwherethevaluecaneitherbealogical1oralogical0.

DissolvedOxygen(DO)

Theoxygendissolvedinliquid,usuallyexpressedinmilligramsperlitre(mg/L)orpercentsaturation.

DomesticWastewater

Wastewaterderivedprincipallyfromdwellings,businessbuildings,institutionsandthelink.Itmayormaynotcontaingroundwater,surfacewater,orstormwater.

DopplerBeatFrequency

Thefrequencydeterminedduringtheprocessofbouncingacontinuouswaveradarsignalfromamovingtarget.

“Dumb”AnalogInput/Output

Card

AninputoroutputcardthatdoesnothaveHARTcommunicationprotocolonit.

E

Echo Asignalthathasbeenreflectedwithsufficientmagnitudeanddelaytobeperceivedinsomemannerasasignaldistinctfromthatdirectlytransmitted.Echoesarefrequentlymeasuredindecibelsrelativetothedirectlytransmittedsignal.

EchoConfidence

Therecognitionofthevalidityoftheechoasindustrylevel.Ameasureofechoreliability.

EchoLockWindow

Awindowcenteredonanechoinordertolocateanddisplaytheecho’spositionandtruereading.

EchoMarker Amarkerthatpointstotheprocessedecho.

EchoProcessing

Theprocessbywhichtheradarunitdeterminestheecho.

EchoProfile Agraphicaldisplayofaprocessedecho.

EchoStrength DescribesthestrengthoftheselectedechoindBabove1mVrms.

ElectronicDevice

Description(EDD)

AnothernameforDeviceDescription(DD).SeedefinitionforDeviceDescription.

ElectronicDevice

DescriptorLanguage

(EDDL)

ThelanguagethattheDeviceDescription(DD)iswrittenin.

F

FalseEcho Anechocausedbytheinternalstructureofacontainer.Obstructionsandincorrectunitplacementwillreturnechoesthatdonotreflectlevel.



FigureofMerit Aquantitycharacterizingperformanceofadevice,system,ormethodinrelationorcomparisontosimilaralternatives.Engineeringfrequentlydefinesfiguresofmeritformaterialsordevicestodeterminetheirrelativeutility.

FloatSwitch Anelectricalswitchoperatedbyafloatinatankorreservoirandusuallycontrollingthemotorofapump.

Flocculant Water-solubleorganicpolyelectrolytesthatareusedaloneorinconjunctionwithinorganiccoagulants,suchasaluminumorironsalts,toagglomeratethesolidspresenttoformlarge,denseflocparticlesthatsettlerapidly.

Flocculatingtank

Atankusedfortheformationofflocbythegentleagitationofliquidsuspensions,withorwithouttheaidofchemicals.

Flotation 1)Separationofsuspendedparticles,oroilandgrease,fromsolutionbynaturallyorartificiallyraisingthemtothesurface,usuallywithair.

2)Thickeningofwasteactivatedsludgebyinjectingairintoitandintroducingthemixtureintoatankwheretheairbuoysthesludgetothesurface.

Flow 1)Themovementofastreamofwaterorotherfluidfromplacetoplace;themovementofsilt,water,sand,orothermaterial.

2)Thefluidthatisinmotion.

3)Thequantityorrateofmovementofafluiddischarge;thetotalquantitycarriedbyastream.

4)Toensureforthordischarge.

5)Theliquidoramountofliquidperunittimepassingagivenpoint.

FlowRate Thevolumeormassofagas,liquid,orsolidsmaterialthatpassesthroughacrosssectionofconduitinagiventime;measuredinsuchunitsaskilogramsperhour(kg/h),cubicmetrespersecond(m3/s),litresperday(L/d),orgallonsperday(gpd).

Flume Aprimarymeasuringdeviceusedtomeasureliquidflow(Forexample,seeParshallflume).

FMCW(Frequencymodulatedcontinuous

wave)

Indirectradarlevelmeasurementtechniqueinwhichtheradardevicemodulatesthefrequencyofthetransmittedsignal.Levelismeasuredbycalculatingthedifferencebetweenthetransmittedsignalandthereturnsignal.

Frequency Thenumberofperiodsoccurringperunittime.Frequencymaybestatedincyclespersecond.

G

Gain Measuresoftheabilityofacircuittoincreasethepoweroramplitudeofasignalfromtheinputtotheoutput.

GritChamber Adetentionchamberoranenlargementofasewerdesignedtoreducethevelocityofflowoftheliquidtopermittheseparationofmineral(grit)fromorganicsolidsbydifferentialsedimentation.

H

HART® HighwayAddressableRemoteTransducer.Anopencommunicationprotocolusedtoaddressfieldinstruments.HARTisaregisteredtrademarkofHARTCommunicationFoundation.Seewww.hartcomm.orgformoredetails.

Head Theheightofthefreesurfaceoffluidaboveanypointinahydraulicsystem;ameasureofthepressureorforceexertedbythefluid.

HeadLevel Thetermusedforthelevelofwaterinaweir.



http://www.hartcomm.org

I

IndustrialWastewater

Wastewaterderivedfromindustrialsourcesorprocesses.

Influent Water,wastewater,orotherliquidflowingintoareservoir,basin,treatmentplant,ortreatmentprocess

Inlet 1)Asurfaceconnectiontoadrainpipe.

2)Astructureathediversionendofaconduit.

3)Theupstreamendofanystructurethroughwhichwatermayflow.

4)Aformofconnectionbetweenthesurfaceofthegroundandadrainorsewerfortheadmissionofsurfaceorstormwater.

5)Anintake.

IntermediateFrequency

Afrequencytowhichasignalwaveisshiftedlocallyasanintermediatestepintransmissionorreception.

IntrinsicallySafe

IntrinsicSafetyisaprotectionmethod,usedforcertifyingelectricalequipmenttobeusedexplosiveatmospheres(flammablegasorcombustibledust),inwhichanysparkorthermaleffectproducedbytheequipmentisnotcapableofcausingignition.

J,K,L

LaminarFlow Non-turbulentflow.

LongShot Describesalengthofmeasurementbeyond1m(3ft.).

M

Manningformula

Aformulaforopen-channelflowpublishedbyRobertManningin1890.

Margin Thedifferencecalculatedbetweentheconfidenceandthethreshold.

MasterDevice Adeviceinamaster-slavesystemthatinitiatesalltransactionsandcommands(e.g.centralcontroller).

MasterSlaveProtocol

Communicationsysteminwhichalltransactionsareinitiatedbyamasterdeviceandarereceivedandrespondedtobyaslavedevice.

Measurement Eachtimeatransmitpulseorsetnumberofpulsesissenttothetransducer.

Microwaves Thetermfortheelectomagneticfrequenciesoccupyingtheportionoftheradiofrequencyspectrumabove1GHz.

MicrowaveFrequency

Microwaveradarbeamsrangeinfrequencybetween5.8GHzand26GHz.

Modbus® Aprotocolusedtoestablishmaster-slave/client-servercommunicationbetweenintelligentdevices.Itisatrulyopen,defactostandard,andthemostwidelyusednetworkprotocolintheindustrialmanufacturingenvironment.ModbusisaregisteredtrademarkofSchneiderElectric.Seewww.modbus.org.

Modem Adevicethattransmitsdataoveraphonelinebymodulatingthedigitalsignalsintoanalogsignalsatonesideandtransmittingthatanalogsignaloveraphoneline.Atthereceivingend,itdemodulatestheanalogsignalbackintoadigitalsignal.

MotorController

Aspecializedtypeofcontrollerwhosetypicalfunctionsperformedbyamotorcontrollerinclude:starting,accelerating,stopping,reversing,andprotectingmotors.



http://www.modbus.org

Multi-master Morethanonemasterdeviceonthebus.

MultipleEchoes

Echoescausedbytheparaboliceffectofradartransmissioninsideadishedtopvesselorahorizontalcylindricaltank.Thesetypesofechoessurpassthereallevelwithinatank.

Multi-slave Morethanoneslavedeviceonthebus.

N

Nappe Thesheetorcurtainofwateroverflowingaweirordam.Whenfreelyoverflowinganygivenstructure,ithasawell-definedupperandlowersurface.

NearBlanking Ablindzonethatiscreatedinfrontofatransducerorantennatoblocktheunitfromreadingfalseechoes.

Nozzle Alengthofpipemountedontoavesselthatsupportstheflange.

O

OpenChannel Anynaturalorartificialwaterconduitinwhichwaterflowswithafreesurface.

OpenChannelFlow

Flowofafluidwithitssurfaceexposedtotheatmosphere.Theconduitmaybeanopenchanneloraclosedconduitflowingpartlyfull.

P

Parameters Inprogramming,variablesthataregivenconstantvaluesforspecificpurposesorprocesses.

ParshallFlume AcalibrateddevicedevelopedbyRalphParshallformeasuringtheflowofliquidinanopenconduitconsistingessentiallyofacontractinglength,athroat,andanexpandinglength.AtthethroatisasilloverwhichtheflowpassesatBelanger’scriticaldepth.Theupperandlowerheadsareeachmeasuredatadefinitedistancefromthesill.Thelowerheadneednotbemeasuredunlessthesillissubmergedmorethan67%.

Peer-to-PeerProtocol

Communicationsysteminwhichalltransactionscanbeinitiatedbyanydeviceonthenetworktoanyotherdeviceonthenetwork.

Primaryeffluent

Theliquidportionofwastewaterleavingtheprimarytreatmentprocess.

PrimarySedimentation

Tank

Thefirstsettlingtankfortheremovalofsettleablesolidsthroughwhichwastewaterispassedinatreatmentworks.Sometimescalledaprimaryclarifier.

PrimarySludge Sludgeobtainedfromaprimarysedimentationtank.

PrimaryTreatment

1)Thefirstmajortreatmentinawastewatertreatmentfacility,usedforthepurposeofsedimentation.

2)Theremovalofasubstantialamountofsuspendedmatter,butlittleornocolloidalanddissolvedmatter.

3)Wastewatertreatmentprocessesusuallyconsistingofclarificationwithorwithoutchemicaltreatmenttoaccomplishsolid-liquidseparation.

ProcessDeviceManager(PDM)

AprogrammadebySiemensthatisusedtoconfigure,maintain,andtrouble-shootfielddevicesonHARTandPROFIBUSnetworks.

ProcessTemperature

Thetemperatureofthegas,vapour,orairlocatedabovethematerialbeingprocessed.



PROFIBUS Acommunicationprotocolusedtoaddressfieldinstruments.DifferenttypesincludeFMS(FieldbusMessagingSystem),DP(DecentralizedPeriphery),PA(ProcessAutomation).Seewww.profibus.comformoredetails.

Profile See“EchoProfile.”

ProgrammableLogic

Controller(PLC)

Anindustrialcomputerthatacceptsinputsfromtherealworld,runsaprogram,thengeneratesoutputstotherealworldthatisusedtocontrolprocesses.

Protocol Asetofrulesthatgoverntheexchangeofinformationbetweentwoormoredevices.

PumpingStation

1)Afacilityhousingrelativelylargepumpsandtheirappurtenances.Pumphousesistheusualtermforsheltersforsmallwaterpumps.

2)Afacilitycontainingliftpumpstofacilitatewastewatercollectionorreclaimedwaterdistribution.

PTFE AnacronymforPolytetrafluoroethylene.

Q,R

Radar RadarisanacronymforRAdioDetectionAndRanging.Adevicethatradiateselectromagneticwavesandusesthereflectionofsuchwavesfromdistantobjectstodeterminetheirexistenceorposition.

Range Distancebetweenatransmitterandatarget.

RangeExtension

Thedistancebelowthezeropercentoremptypointinavessel.

Relay Anelectricaldevicethatisdesignedtointerpretinputconditionsinaprescribedmannerandafteraspecifiedconditionsaremet,torespondtocauseelectricaloperationorsimilarabruptchangeinassociatedcontrolcircuits.Themostcommonformofrelayusesacoilandsetofcontacts.Whencurrentflowsinthecoil,contactsareopenedorclosed,dependingontheirarrangement.Relaysaresaidtobenormallyclosed.

Ringing Theinherentnatureofthetransducertocontinuevibratingafterthetransmitpulsehasceased.SeeBlanking.

S

Sampler Adeviceusedwithorwithoutflowmeasurementtoobtainaportionofliquidforanalyticalpurposes.Maybedesignedfortakingsinglesamples(grab),compositesamples,continuoussamples,orperiodicsamples.

Scum 1)Theextraneousorforeignmatterthatrisestothesurfaceofaliquidandformsalayerorfilmthere.

2)Aresiduedepositedonacontainerorchannelatthewatersurface.

3)Amassofsolidmatterthatfloatsonthesurface.

SecondaryEffluent

1)Theliquidportionofwastewaterleavingsecondarytreatment.

2)Aneffluentthat,withsomeexceptions,containsnotmorethan30mg/Leach(ona30-dayaveragebasis)ofBOD5andsuspendedsolids.

SecondarySedimentation

Tank

Asettlingtankfollowingsecondarytreatmentdesignedtoremovebygravitypartofthesuspendedmatter.Alsocalledasecondaryclarifier.

SecondaryTreatment

1)Generally,aleveloftreatmentthatproducessecondaryeffluent.



http://www.profibus.com

2)Sometimesusedinterchangeablywiththeconceptofbiologicalwastewatertreatment,particularlytheactivated-sludgeprocess.Commonlyappliedtotreatmentthatconsistschieflyofclarificationfollowedbyabiologicalprocesswithseparatesludgecollectionandhandling.

Sedimentation 1)Theprocessofsubsidenceanddecompositionofsuspendedmatterorotherliquidsbygravity.Itisusuallyaccomplishedbyreducingthevelocityoftheliquidbelowthepointatwhichitcantransportthesuspendedmaterial.Alsocalledsettling.Itmaybeenhancedbycoagulationandflocculation.

2)Solid-liquidseparationresultingfromtheapplicationofanexternalforce,usuallysettlinginaclarifierundertheforceofgravity.Itcanbevariouslyclassedasdiscrete,flocculent,hindered,andzonesedimentation.

SedimentationTank

Abasinortankinwhichwastewatercontainingsettleablesolidsisretainedforremovalofthesuspendedmatterbygravity.Alsocalledasedimentationbasin,settlingbasin,settlingtank,orclarifier.

SettlingTank Atankorbasininwhichwater,wastewater,orotherliquidscontainingsettleablesolidsareretainedforasufficienttime,andinwhichthevelocityofflowissufficientlylowtoremovebygravityapartofthesuspendedmatter.

ShortShot Describesalengthofmeasurementwithin1m(3ft.).

Shot Onetransmitpulseormeasurement.

SlaveDevice Adevice(e.g.transmitterorvalve)inamaster-slavesystemthatreceivescommandsfromamasterdevice;aslavedevicecannotinitiateatransaction.

Sludge 1)Theaccumulatedsolidsseparatedfromliquidsduringthetreatmentprocessthathavenotundergoneastabilizationprocess.

2)Theremovedmaterialresultingfromchemicaltreatment,coagulation,flocculation,sedimentation,flotation,orbiologicaloxidationofwaterorwastewater.

3)Anysolidmaterialcontaininglargeamountsofentrainedwatercollectedduringwaterorwastewatertreatment.

SludgeBlanket Accumulationofsludgehydrodynamicallysuspendedwithinandenclosedbodyofwaterorwastewater.

Slurry Athickwaterymudoranysubstanceresemblingit,suchaslimeslurry.

SmartProcessInstrumentation

Microprocessor-basedinstrumentationthatcanbeprogrammed.Ithasmemory,andiscapableofperformingcalculationsandself-diagnosticsandreportingfaults,andcanbecommunicatedwithfromaremotelocation.

Stillpipe Apipethatismountedinsideavesselperpendiculartothevesselwall,andisopentothevesselatthebottom.Thisistypicallyusedonvesselsthathavealotofturbulenceorfoam.Thestillpipeprovidesacalmliquidsurfaceequaltothelevelinthevessel.

Submergence 1)Theconditionofaweirwhentheelevationofthewatersurfaceonthedownstreamsideisequaltoorhigherthanthatoftheweircrest.

2)Theratio,expressedasapercentage,oftheheightofthewatersurfacedownstreamfromaweirabovetheweircresttotheheightofthewatersurfaceupstreamabovetheweircrest.Thedistancesupstreamordownstreamfromthecrestatwhichsuchelevationsaremeasuredareimportant,buthavenotbeenstandardized.

3)Inwaterpowerengineering,theratiooftailwaterelevationtotheheadwaterelevationwhenbotharehigherthanthecrest.Theoverflowcrestofthestructureisthedatumofreference.Thedistancesupstreamordownstreamfromthecrestatwhichheadwaterandtailwaterelevationsaremeasuredareimportant,buthavenotbeenstandardized.

4)Thedepthoffloodingoverapumpsuctioninlet.

SuppressedWeir

Aweirwithoneorbothsidesflushwiththechannelapproach.Thispreventscontractionofthenappeadjacenttotheflushside.Thesuppressionmayoccurononeendorbothends.



T

TimedRelay Arelaywhoseopeningorclosingisdelayedforaspecifiedamountoftimeaftertheoccurrenceofatriggerevent.

Totalizer Adeviceusedtocountpulses.Typicallyusedtocountthenumberofrelayclosures.

TotallyIntegrated

Automation(TIA)

ASiemensconceptforhavingallcomponentsofanautomationsystemtiedtogetherusingadvancedcommunicationprotocolsandtotallyintegratedtogether.

Turbidity 1)Aconditioninwaterorwastewatercausedbythepresenceofsuspendedmatterandresultinginthescatteringandabsorptionoflight.

2)Anysuspendedsolidsimpartingavisiblehazeorcloudinesstowaterthatcanberemovedbyfiltration.

3)Ananalyticalquantityusuallyreportedinturbidityunitsdeterminedbymeasurementsoflightscattering.

Turbulence 1)Thefluidpropertythatischaracterizedbyirregularvariationinthespeedanddirectionofmovementofindividualparticlesorelementsoftheflow.

2)Astateofflowofwaterinwhichthewaterisagitatedbycrosscurrentsandeddies,asopposedtolaminar,streamline,orviscousflow.

TVT(timevarying

threshold)

Atime-varyingcurvethatdeterminesthethresholdlevelatwhichtheechoisprocessed.

U,V,W,X,Y,Z

Ullage Amountofspaceleftinavesselinorderforittobefilled.Asopposedtothevolumeofmaterialinavessel.



WorksCitedBoyes,Wait.“TheChangingStateoftheArtofLevelmeasurement,”FlowControlMagazine,February1999.

Carlson,Al.“OpenChannelFlowmetering,”June1998.

Carlson,Al.“TheRightTransducerfortheJob,”June1999.

Crabtree,Mick.PressureandLevel,CrownPublications(Pty)Ltd.,1998,pg39–48.

Duncan,Doug.“UltrasonicSensors:Nowanevenbetterchoiceforsolidmaterialleveldetection,”Instrumentation&ControlSystems.November1998.

Evans,Jack.“Ultrasonicscomesofageforsolidsandliquids,”inTech.April1997,pg39–42.

Felton,Bob.“Levelmeasurement:AncientChore,moderntools,”InTech,August2001.

Grant,DouglasM.andBrianD.Dawson.IscoOpenChannelFlowMeasurementHandbook.FifthEdition,ISCOInc.,1997.

Hughes,ThomasA.LevelMeasurementandControl,ISAPress,2002.

Li,Gordon.“AdvancedCircuitryImprovesSignal-to-NoiseRatio,”2003.

Massa,Frank.“Somepersonalrecollectionsofearlyexperiencesonthenewfrontierofelectroacousticsduringthelate1920sandearly1930s,”TheJournaloftheAcousticalSocietyofAmerica.April1985.pg1296–1302.

MassaProductsCorp.“FundamentalsofElectroacoustics,”

www.massa.com/fundamentals.htm

Milligan,Stephen.“HowtoInstallUltrasonicTransducers,”2003.

Sirlty,PaulA.“AnIntroductiontoUltrasonicSensing,”Sensors,Nov.1989.



http://www.massa.com/fundamentals.htm

Copyright©SiemensMilltronicsProcessInstruments2012.

Allrightsreserved.

Noportionofthisbookmaybereproducedinanyformwithoutpermissioninwritingfromthepublisher.

FirstEdition,2006.SecondEdition,2008.ThirdEdition,2012

ISBN-10:ISBN0-9782495-0-X

ISBN-13:ISBN978-0-9782495-0-2

PrintedandboundinCanadaforSiemensMilltronicsProcessInstrumentsPeterborough,ONK9J7B2

www.siemens.com/processautomation



http://www.siemens.com/processautomation

Documents

Understanding Ultrasonic Level Measurement · for general background information. They are too numerous to mention, but their enthusiasm for the technology and their efforts are much