资源预览需要最新版本的Flash Player支持。
您尚未安装或版本过低,建议您
毕业设计（外文翻译）题目标准筛振筛机的总体及夹紧装置的设计系别专业名称机械设计制造及其自动化班级学号学生姓名指导教师二O一一年三月COALPREPARATIONTABLE714EFFECTOFGEOMETRYANDCONCENTRATIONOFFEEDSOLIDSONTHROUGHPUTFORA1/6IN,DIAMHYDROCYCLONECLEANING1/4INVARYINGTHEDISTANCEBETWEENTHEBOTTOMOFTHEVORTEXFINDERANDTHEHYDROCYCLONECONEBOTTOMFOREXAMPLE,THEWASHEDCOALASHCANBEREDUCEDBYDECREASINGTHEDIAMETEROFTHEVORTEXFINDER,DECREASINGTHELENGTHOFTHEVORTEXFINDER,ORINCREASINGTHEDIAMETEROFTHEUNDERFLOWORIFICEINCREASINGFEEDSOLIDSCONTENTINCREASESTHESPECIFICGRAVITYOFSEPARATIONAND,THEREFORE,WASHEDCOALYIELDANDASH,WHICHINDICATESTHEIMPORTANCEOFMAINTAININGACONSTANTFEEDSOLIDSCONTENTTOPRESERVEWASHEDCOALQUALITYCAPACITYISINFLUENCEDBYCYCLONEGEOMETRY,IE,THESIZESOFTHEOVERFLOW,UNDERFLOW,ANDINLETOPENINGS,ANDBYFEEDSOLIDSCONTENTTHEEFFECTSOFTHESEPARAMETERSISGIVENINTABLE714INCREASINGINLETPRESSUREISASIMPLEMETHODOFINCREASINGCAPACITYWITHOUTCHANGINGHYDROCYCLONEGEOMETRY,ANDWASHEDYIELDANDASHARENOTSIGNIFICANTLYAFFECTEDHOWEVER,THEPENALTYISINCREASEDPUMPINGCOST,ANDDEGRADATIONOFTHECOALFLOWSHEETSSOONAFTERTHEHYDROCYCLONEWASDEVELOPED,ITBECAMEEVIDENTTHATPERFORMANCEWASINFERIORTONEARLYALLOTHERCLEANINGDEVICESCONSEQUENTLY,INANEFFORTTOIMPROVEPERFORMANCE,THREETWOSTAGECIRCUITS,SHOWNINFIG764,WEREDEVELOPEDINTHEEARLIESTTWOSTAGECIRCUIT,CALLEDTWOSTAGERELEARNORTSR,THEREFUSEFROMAPRIMARYHYDROCYCLONEISSIMPLYRELEARNEDINASECONDARYHYDROCYCLONE,THEOVERFLOWSFROMTHETWOHYDROCYCLONESARERECOMBINEDASTHEWASHEDCOALPRODUCT,ANDTHEUNDERFLOWSFROMTHESECONDARYHYDROCLONECONTAINSTHEFINALREFUSEINMORERECENTINSTALLATIONS,ONEOFTHEPRODUCTSFROMTHESECONDARYHYDROCYCLONEISRECIRCULATEDTOTHEFEEDOFTHEPRIMARYHYDROCYCLONEINTHETWOSTAGEOVERFLOWRECIRCULATIONCIRCUIT,TSOR,THEPRIMARYORFIRSTSTAGEHYDROCYCLONEISADJUSTEDTOPRODUCEANACCEPTABLECLEANCOALANDTHESECONDARYHYDROCYCLONEISADJUSTEDTOPRODUCEAREFUSEESSENTIALLYFREEOFMISPLACEDCOALTHEOVERFLOWFROMTHESECONDARYHYDROCYCLONE,WHICHCONTAINSTHEMISPLACEDCOALINTHEUNDERFLOWSOFTHEPRIMARYHYDROCYCLONE,ISRETURNEDTOTHEFEEDOFTHEPRIMARYHYDROCYCLONEFORREPROCESSINGINTHETWOSTAGEUNDERFLOWRECIRCULATIONCIRCUIT,TSUR,ANDTHEOVERFLOWISRELEARNEDINTHESECONDARYHYDROCYCLONETHEUNDERFLOWFROMTHESECONDARYHYDROCLONEISRECALCULATEDTOTHEFEEDOFTHEPRIMARYHYDROCYCLONETHEOVERFLOWFROMTHESECONDARYHYDROCYCLONECONTAINSTHEWASHEDCOALEACHOFTHESECIRCUITSHASADVANTAGESTHATDEPENDUPONTHESIZEANDSPECIFICGRAVITYCOMPOSITIONSOFTHEFEED,ASWELLASTHEREQUIREDWASHEDCOALQUALITYTHETSORCIRCUITISMOREEFFECTIVEINRECOVERINGWASHEDCOALWHEREASTHETSURCIRCUITISMOREEFFECTIVEINREJECTINGHEAVYIMPURITYTHETSRCIRCUITISMOSTEFFECTIVEWHENTHESPECIFICGRAVITYOFSEPARATIONOFTHETWOHYDROCYCLONESISSIMILARCONVERSELY,THEPERFORMANCEOFTSORANDTSURISIMPROVEDBYDIVERGINGTHESPECIFICGRAVITYOFSEPARATIONOFTHETWOCYCLONESATTHEPRESENTTIME,THETSORISTHEMOSTCOMMONCIRCUITAVARIATIONOFTHETSRCIRCUITHASBEENPROPOSEDWHEREBYUNDERFLOWFROMTHEPRIMARYCYCLONEISRELEARNEDONACONCENTRATINGTABLERATHERTHANASECONDARYHYDROCYCLONESOMEPLANTSUSINGJIGSTOCLEANTHECOARSECOALUTILIZEHYDROCYCLONESTOIMPROVEPERFORMANCEONTHEFINERSIZESONEMETHODISTORELEARNTHEUNDERFLOWOFTHEWASHEDCOALSCREEN,COMMONLYTHE1/4INMATERIAL,WITHHYDROCYCLONESANOTHERMETHODISTOSCREENTHERAWCOALATABOUTTHISSIZEANDCLEANTHEUNDERSIZEWITHHYDROCYCLONESHYDROCYCLONESHAVEBEENUSEDAHEADOFDENSEMEDIUMCYCLONESTOREMOVESOMEOFTHELOWSPECIFICGRAVITYCOALANDTHEREBYREDUCETHEAMOUNTOFMATERIALSENTTOTHEDENSEMEDIUMPLANTTHEHYDROCYCLONESAREADJUSTEDTOSEPARATEATASPECIFICGRAVITYOFABOUT135TO140THEADVANTAGEISTHATTHECAPACITYOFTHEDENSEMEDIUMCYCLONEPLANTCANBESMALLER,THUSREDUCINGCAPITALANDOPERATINGCOSTSHYDROCYCLONEPERFORMANCEASMENTIONEDPREVIOUSLY,THEQUALITYOFTHEWASHEDCOALANDREFUSEPRODUCTSCANBEREGULATEDBYCHANGINGTHEDIAMETERSOFTHEOVERFLOWANDUNDERFLOWORIFICESHOWEVERFROMAPERFORMANCESTANDPOINT,ARATIOOFOVERFLOWDIAMETERTOUNDERFLOWDIAMETERINARANGEOFABOUT17TO2GIVESTHEBESTRESULTSPERFORMANCEATLOWERRATIOSISINFERIORALSO,THESOLIDSCONTENTINTHEFEEDTOPRIMARYANDSECONDARYHYDROCYCLONESSHOULDRANGEFROM8TO15BYWEIGHTOUTSIDETHISRANGE,EITHERABOVEORBELOW,PERFORMANCEISADVERSELYAFFECTEDSEPARATIONSOBTAINEDINASINGLEHYDROCYCLONEANDTWOSTAGECIRCUITSTSRARESHOWNBYTHEDISTRIBUTIONCURVESINFIG765THESHARPNESSOFSEPARATIONOFTHETWOSTAGECIRCUITISSIGNIFICANTLYSUPERIORTOTHATOFASINGLEHYDROCYCLONEALSO,THESHARPNESSOFSEPARATIONOFTHETWOSTAGECIRCUITISNOTNEARLYASSHARPASTHESEPARATIONSCHARACTERISTICOFADENSEMEDIUMCYCLONEITFOLLOWSTHENTHATHYDROCYCLONESARENOT
