項(xiàng)目八：常規(guī)物理常數(shù)與性能分析任務(wù)一：粒徑的測(cè)定粒徑的測(cè)定課程：工業(yè)分析中文Scenario8:PhysicalconstantsandperformancetestingTask1:DeterminationofparticlesizeDeterminationofparticlesizeCourse:IndustrialAnalysisEglish定義：粒徑是指固體物質(zhì)顆粒的大小

。粒徑的測(cè)定方法有多種，根據(jù)測(cè)定要求的不同，可選擇不同的方法，一般有篩分法、微粒度測(cè)定法等。

只能測(cè)定粒徑范圍可以測(cè)粒徑分布和平均粒徑中文Definition:Particlesizereferstothesizeofsolidmaterialparticles.Therearevariousmethodsformeasuringparticlesize,anddifferentmethodscanbeselectedaccordingtodifferentmeasurementrequirements,generallyincludingsievingmethod,particlesizemeasurementmethod,etc.CanonlymeasureparticlesizerangeCanmeasureparticlesizedistributionandaverageparticlesizeEglish1、方法原理利用系列篩孔尺寸不同的篩網(wǎng)來(lái)測(cè)定顆粒粒度的分布，將篩網(wǎng)按孔徑大小依次疊好，把被測(cè)試樣從頂上倒入，蓋好篩蓋，置于振篩器上振蕩（或人工振篩），使試樣通過(guò)一系列的篩網(wǎng)，然后在各層篩網(wǎng)上收集，通過(guò)稱量各篩網(wǎng)中留存的試樣的質(zhì)量，以粒度來(lái)表示一定的粒徑范圍的顆粒質(zhì)量占總試樣質(zhì)量的百分?jǐn)?shù)。一、篩分法測(cè)定粒徑中文1、MethodprincipleThesievingmethodusesscreenswithdifferentmeshsizestodeterminethedistributionofparticlesize.Whenmeasuring,stackthesievemeshinorderofporesize,pourthetestedsamplefromthetop,coverthesievecover,andplaceitonthevibratingscreentoshake(ormanuallyshake),sothatthesamplepassesthroughaseriesofsievemeshes,andthencollectoneachlayerofsievemesh.Byweighingthemassoftheretainedsampleineachsievemesh,thepercentageofparticlemasswithinacertainparticlesizerangetothetotalsamplemassisrepresentedbyparticlesize.一、DeterminationofparticlesizebysievingmethodEglish2、儀器孔徑分別為1.0mm、2.0mm、2.8mm、4.0mm等的篩網(wǎng)一套，并附有篩蓋和底盤，如圖所示，振篩器（沒(méi)有振篩器則采用人工振篩）及托盤天平。篩網(wǎng)篩蓋和底盤中文2、InstrumentAsetofscreenswithaperturesof1.0mm,2.0mm,2.8mm,4.0mm,etc.,equippedwithscreencoversandchassis,asshowninthefigure.Thevibratingscreen(ifthereisnovibratingscreen,manualvibratingscreenwillbeused)andatraybalancewillbeused.screenmeshscreencoverandchassisEglish3、篩網(wǎng)目數(shù)與尺寸對(duì)應(yīng)關(guān)系

中文3、TherelationshipbetweenthenumberofsievemeshanditssizeMeshcountmicronEglish4、測(cè)定步驟稱取試樣適量（一般200g），精確到1g。將篩網(wǎng)按孔徑大小依次疊好（若僅測(cè)定規(guī)定粒度范圍的測(cè)定，只在用兩個(gè)確定孔徑的篩網(wǎng)），孔徑大（4.0mm）的在上層，小的在下層。試樣置于孔徑最大的篩網(wǎng)上，蓋好篩蓋。將篩網(wǎng)置于振篩器上，夾緊，振蕩5min。稱量未通過(guò)4.0mm孔徑篩網(wǎng)的試樣及底盤上的試樣（通過(guò)所有篩網(wǎng)的小顆粒物），精確到1g。

中文4、MeasurementstepsWeighanappropriateamountofthesample(usually200g),accurateto1g.Stackthesievesinorderofporesize(ifonlymeasuringthespecifiedparticlesizerange,onlytwosieveswithdeterminedporesizesareused),withthelargerporesize(e.g.4.0mm)ontheupperlayerandthesmalleroneonthelowerlayer.Placethesampleonthesievewiththelargestporesizeandcoveritwiththesievecover.Placethesieveontheshaker,clampit,andoscillatefor5minutes.Weighthesamplethatdidnotpassthe4.0mmaperturesieveandthesampleonthechassis(smallparticlespassingthroughallsieves),accurateto1g.Eglish5、數(shù)據(jù)處理

中文5、Resultcalculation

Theparticlesizeofthesampleisexpressedasthefractionofparticleswithamassof1-4mmtothetotalmassofthesample：D--Theparticlesizeofthesample；m--Massofthesample,g；m’--Thesumofthelargeparticlesamplethatdidnotpassthe4mmaperturesieveandthesmallparticlesamplethatpassedallsieves,gEglish1、方法原理

固體質(zhì)點(diǎn)在液體介質(zhì)中的沉降速度因質(zhì)點(diǎn)直徑大小不同而不同，通過(guò)離心力的作用，加速固體質(zhì)點(diǎn)的沉降速度，固體質(zhì)點(diǎn)按粒徑大小先后到達(dá)儀器的光束位置而被檢測(cè)器檢測(cè)。二、微粒度儀法（離心沉降法）中文1、Methodprinciple

Thesettlingspeedofsolidparticlesinliquidmediavariesdependingontheparticlediameter.Throughtheactionofcentrifugalforce,thesettlingspeedofsolidparticlesisaccelerated.Solidparticlesreachthebeampositionoftheinstrumentinorderofparticlesizeandaredetectedbythedetector.二、Particlesizeanalyzermethod(centrifugalsedimentationmethod)Eglish2、操作要點(diǎn)（1）試樣的分散選擇合適分散劑如乳化劑制成穩(wěn)定的懸浮液（2）沉降液的選擇密度、黏度合適，密度應(yīng)低于固體密度且不使固體顆粒溶脹，常用水、甘油水、蔗糖水為沉降液中文2、Operationpoint(1)DispersionofsamplesChooseappropriatedispersantssuchasemulsifierstocreatestablesuspensions(2)SelectionofsettlingsolutionThedensityandviscosityofthesettlingsolutionareappropriate,andthedensityshouldbelowerthanthesoliddensitywithoutcausingthesolidparticlestoswell.Water,glycerolwater,andsucrosewaterarecommonlyusedassettlingsolutionsEglish（3）緩沖液的選擇緩沖液是為了使沉降液產(chǎn)生適當(dāng)?shù)拿芏忍荻瘸Ｓ眉状妓芤?、乙醇水溶液、蒸餾水中文(3)Sel