灰分仪进口灰分仪灰分在线测量装置广州瑞发公司供应高质量灰分仪、灰分在线测量装置。进口灰分仪其精度和稳定性均表现十分优越。同时提供相似的国产灰分仪，品质好，价格低。灰分仪其主要原理特点用英文介绍如下： Continuousdeterminationofashincoalandincoalturbid MEASURINGPRINCIPLE灰分仪测量原理 Electro-magneticwaveslikeX-raysorgamma-raysareabsorbedinmaterialbydifferentways.Thereforeitdependsontheenergyoftheradiationandonthematerialitselfinwhichwayitisabsorbed.Highenergywavesandlowatomicnumbersareabsorbedaccordingtothedensity(orbulkdensity)ofthematerial.Ofcoursetheabsorption alsoisdependingonthelayerthickness.Thatmeanstheabsorptionisdependingontheweightofthematerial theradiationhaspassedthrough(Theweightincreasesifthewaybecomeslongerorifthedensitybecomeshigher).Densityandthicknesscanbemeasuredbymeansofradiations:Ifoneisconstanttheothercanbecalculated. Lowerenergyradiationandhigheratomicnumbersareabsorbedinthesamewaybutadditionalaccordingtothe atomicweight.Ashighertheatomicweightandaslowertheenergyashighertheabsorption. Foranalysispurposesaweakenergyisneededtodeterminetheatomiccomposition.Butalsotheweightisinfluencing theabsorption.Soahigherenergyradiationalsomustbeappliedtogetasignalwhichisinfluencedbytheweightonlybutnotbytheatomiccomposition.Bothsignalscanbeusedmathematicallytodeterminethecomposition. THETECHNIC灰分仪技术要点 Tomeasureradiationitmustbeabsorbed.Theabsorptionishigherasmoredenstheabsorbermaterialis.There aregasfilledionisationchambersorGeigertubesavailablebutthemostsensitiveisacrystalofNaJwitha densityof3.7g/cm3.Thiscrystalproducesasmalllightflasheswhenexposedtoradiationwhichmust bedetectedbyalightamplifiercalledphoto-multiplier.Thewholedetectormustbebuildinamechanicalprotectionandlighttighthousingandalsostabelizedagainstanychanges. Thetwosourcesofradiationhavetobeshieldedinleadcontainerstopreventtheraystotravellinalldirections.Byathinchannelitisensuredthatonlyinonedirectiontheworkingbeamisallowedtocomeout.Theradiationismeasuredbyascintillationcounterwhichisthemostsensitivedetectoravailableforindustrialapplications. Both,sourceanddetector,iscalledmeasuringpath.Twomeasuringpathesarenecessaryforashdetermination. Itwouldbepossibletouseonlyonedetectorforbothradiationsbutbecausephysicallyinthedetectoreachradiations influencestheotheritismorereliabletouseseparateones. Eithersourceordetectorcanbeinstalledaboveorunderneeththebelt.Themeasuringpathesshouldhaveadistanceof1mminimumtoeachother.Afirmmechnicalframeisneededtopreventchangesofthedistancebetweensourceanddetector:Itmustbeabsolutellyconstanttoavoidmeasuringerrors. PRACTICALAPPLICATION灰分仪实际应用 AradiationsourcewithCaesium-137isanemitterofrelativelyhighenergyradiation.Theenergyishighenough tobeindependentonthecompositionandlowenoughtohandleitinasecureway.Itisabletodeteminetheweightofthematerialwhichithaspassedthroughwithahighprecitionsothatforinstanceradiometricbeltscales areusingit. AnothermaterialemmitingradiationisAmericium-241.Thisenergyisquietelow:Asheetofsteelof0.8mmthickness isweakeningtheintensitytothehalf.IncoalthepartwhichiscalledashabsorbstheradiationoftheAm-241 muchmorethenthecarbon.Soahigherashcontentgivesanrelativlystrongincreaseoftheabsorption.Unfortunatellythereisnopracticalwaythatthisabsorptionisnotinfluencedbydensityorlayerthicknesse.g.loadingonabelt.Thereforebothsignalsareneededtogethertocalculatemathematicallythepercentageofash. THEEVALUATION Aprogramjustusinghighlysophisticatedmathematicsisnothelpingtheuser:Itmustbeappliable.Theashanalysermustbeabletobecalibratedwithoutextendedmathematicalbackground.Therforatableisstoredinthe evakuationunitwherelaboratoryvaluescanbestoredandusedascomparison.Aautomaticalroutinefordetermination ofthecalibrationcurvefindsthecoeffcientsandshowsimmidiatellyhowgoodthefitwas. Butnotonlythesimpledisplayofthemeasuringresultsisimportant.Theallreadymentionedtablecanbeused asadatastorage.Allmeasuringvaluesareshownoveratimeperiodof1hour,1shiftand1daybackfor30days. Intheservicemenuthesoftwareisabletochangethewiringterminalssothatarelayorananalogueoutput canbeswitchedfromoneterminaltoanother. Thereforetheevakuationunitisnotonlyandisplayofashbutfitsintotheprocessandcanhelpthocontroll it. ACCURACY灰分仪精度 Afewinfluencesareresponsibleforpossibleerrorsandgoodorbadaccuracy. Thecoalcommingfromonemineonlynormallyanaccuracyofbetterthen 0.5%standarderrorforabout10%ashalsowithcorsecoal.Forashcontentslowerthen10%evenbetterresultsareachieved.Forhigherashcontentstheerrorisbiggerbutnotbecauseoftheprinciplebutrelatedtothehighererrorofthelaboratories. Thesystemmustbecalibratedwithanerrorof0.3%causedbythelaboratotiesandthereforehasarestrictedaccuracy. Themostimportantpossibleerroriscausedbythecoalitself:Themeasuringprincipleisbasedondistinguishingtwocomponents.Inrealityitissomethingliketen.Anychangeofthecompositionoftheashcausesaslighterror.Becausethetwomaincomponentsdohavenearlythesameabsorptioncoefficientthisratiodoesnotcauseawrong indication.Theattentionmustbeputonchangeslikesuchinironcontent.Thetheoreticalerrorcanbeverybigbutisnotveryimportantinpractice.Neverthelessithastobeconsidered. Anothererrorcanbecausedbythemoisturecontent.Onlywhentheashcontentisabout5-10%isdoesnotcauseanerrorbecausewaterismeasuredascoal.Forhighercontentsiscancauseanerror.FortunatellythiscanbecompensatedforwithanRGImicrowavemoisturemeter.