灰份儀進口灰份儀灰份在線測量裝置廣州瑞發公司供應高質量灰份儀、灰份在線測量裝置。進口灰份儀其精度和穩定性均表現十分優越。同時提供相似的國產灰分儀，品質好，價格低?；曳輧x其主要原理特點用英文介紹如下： Continuousdeterminationofashincoalandincoalturbid MEASURINGPRINCIPLE灰份儀測量原理 Electro-magneticwaveslikeX-raysorgamma-raysareabsorbedinmaterialbydifferentways.Thereforeitdependsontheenergyoftheradiationandonthematerialitselfinwhichwayitisabsorbed.Highenergywavesandlowatomicnumbersareabsorbedaccordingtothedensity(orbulkdensity)ofthematerial.Ofcoursetheabsorption alsoisdependingonthelayerthickness.Thatmeanstheabsorptionisdependingontheweightofthematerial theradiationhaspassedthrough(Theweightincreasesifthewaybecomeslongerorifthedensitybecomeshigher).Densityandthicknesscanbemeasuredbymeansofradiations:Ifoneisconstanttheothercanbecalculated. Lowerenergyradiationandhigheratomicnumbersareabsorbedinthesamewaybutadditionalaccordingtothe atomicweight.Ashighertheatomicweightandaslowertheenergyashighertheabsorption. Foranalysispurposesaweakenergyisneededtodeterminetheatomiccomposition.Butalsotheweightisinfluencing theabsorption.Soahigherenergyradiationalsomustbeappliedtogetasignalwhichisinfluencedbytheweightonlybutnotbytheatomiccomposition.Bothsignalscanbeusedmathematicallytodeterminethecomposition. THETECHNIC灰份儀技術要點 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灰份儀實際應用 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灰份儀精度 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.