纸机管理.docx

纸机管理.docx

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纸机管理

A.PAPERMACHINECLEANINGMANAGEMENT

ABSTRACTThispaperdiscussestheimportanceofpapermachinecleaningmanagement.Itexplainstheprocessofdeterminingcleaningmanagementstatusforexistingmachinesandsettingupgoalsforimprovements.Thisprocess,cleaningmanagementaudit,helpspapermakersdetectcleaningproblemsthatareaffectingthemachine’sefficiency,paperqualityandsafety.Apost-auditreportincludessuggestionsforimprovingthemill’scleaningmanagementpractices,whichafterimplementationneedtobefolloweduptoensuresustainablegains.Withthestate-of-the-artpapermachinescleaningmanagementistakenintoconsiderationbythedesignofthemachine.Papermillsimprovingtheircleaningmanagementprocesseshavebeenabletoincreaseproductivity.Thishasbeenachievedbyeliminatingbreaksincertainareas,shorteningdowntime,increasingrunnability,improvingpaperqualityandimprovingsafetyINTRODUCTIONPapermachinecleanlinesshasanimpactonpapermachineefficiency,paperqualityandsafety.Withrightpractices,equipmentandtrainingitispossibletopositivelyaffecttheseareas.Theimportanceofthisisacknowledgedinthepaperindustryandintherecentyearsalotofefforthasbeenputintodevelopingpapermachinecleaningmanagementprocesses.Thedevelopmentisongoingandnewtechnologyisdeliveredwithnewmachinesandassmallerprojectstohelpexistingmachines.CLEANINGAUDIT-THEKEYTOIMPROVEMENTWITHEXISTINGMACHINESThepurposeofpapermachinecleaningauditistodeterminethoseareasonanexistingpapermachinewherebettercleaningmanagementwillenhancethemachineproductivity.Theauditstartswithpre-studyandiscompletedonlywhenresultsofimprovementshavebeenrecorded,figure1.

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Figure1.Cleaningauditprinciple.Pre-StudyandGatheringofInformationInthepre-studyphaseallrelevantinformationregardingtheupcomingprojectisgathered.Thisincludesdrawingsofe.g.showerlocationsinwetendandotherrelatedequipmentsuchasmistcollectors,informationofmillcleaningmanagementpracticesincludinge.g.fabricchangeintervals,doctordata,machineandproductiondata,etc.Withthegathereddataitispossibletobeforehandmakeplansonhowtocarryouttheauditandwhatwouldbethepotentialareaswherespecialattentionneedstobepaidduringtheaudit.CarryingouttheAuditTheauditiscarriedoutwhilethemachineisinoperationandcompletedwhenthemachineisdown.Whilethemachineisoperatingthemachineisthoroughlychecked.Theequipmentisevaluatedasarethepracticesofthemilloperations.Functioningofshowers,doctors,trim-squirtsetc.isrecorded.Overallcleanlinessofthemachinewillbetakenintospecialconsideration.Anystructuregoingacrossthemachinehasapotentialofcausingrunnabilityandefficiencyhazardswhengatheringbuild-up.Alsostructuressuchascatwalksandwalkwayswillbeevaluatedfromsafetypointofview.Duringbreaksthemill’scleaningpracticeswillberecorded,andlateroncomparedtothemillinstructions.Itisimportanttocompletetheobservationswithphotos.Thesephotosaddedinthefinalreportwilllateronmakeiteasierforthereadertounderstandthesituation,figure2.

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Figure2.Photoshowingdefectednozzlesinhp-showerandbuild-uponmistcollectorcausingabreakhazard.Onadowndayasimilarfullmachineapproachistakenaswhenthemachineisrunning.Thistimetherearepossibilitiestolookintoplaceswhereitwasimpossibletogettoduringtheproduction:

insidesave-alls,airexhaustductwork,completecheck-upofdoctors,etc.Againthemilloperationpracticesaremonitoredandlatercomparedtomillinstructions.Theauditcanincludethewholemachineorforinstancejustthewetend,ifthat’stheplacewheremostimprovementisneeded.Beforeauditorleavesthemillameetingisheldwherethemillisupdatedwithpreliminaryresultsoftheaudit.ReportandBenchmarkAnimportantpartinpreparingthecleaningmanagementauditreportiscomparingandbenchmarkingthestudiedmillwiththeindustry.Withcomprehensivedatabasesitispossibletopositionthemillinrelationwithothersincludingthebest,whichhelpstheauditorinpointingoutthepotentialforthemillandsettingupgoals.Thesedatabasesareonlyusedbytheauditortohelphimguidingthemilltotherightdirection.Theinformationinthedatabasesincludese.g.:

_Production（t,t/d,kg/cm/d）_Averagebasisweight（g/m²）_Averagespeed（m/min）_Efficiency（%）_Shutdowns（%,interval,duration,planned,unplanned）_Breaks（%,#ofbreaks/d,wetend,dryend）_Broke（%）_Trimloss（%）_Wash-upproceduresduringshutdowns（interval,duration）_Machineclothingshockcleaningproceduresduringshutdowns（interval,duration）

Normalmachinecleaningproceduresduringrun（interval,duration）_Doctormaintenance（bladechangeintervals,wash-upprocedures）_Clothingchange（interval,duration）Whenthereportisreadyitispresentedatthemillandplansforimprovementsaremadebasedonthereport.ImprovementsThereportidentifiestwodifferentareasofimprovements:

thoseunderdirectcontrolofmillmaintenanceandoperatingpersonnel,andthoseaffectedbydesignandequipment.Improvingtheareasunderdirectcontrolofmaintenanceandoperationscanbeachievedbypropertrainingandimplementingcorrectprocedures.Thiscanbeverycosteffectiveyetyieldinggoodresults.Forexamplewashingthedoctorsfromfrontsidetobackandneglectingthebacksidecancauseaccumulatedbuild-upwhichwilleventuallycreateproblems;quiteoftenthecaseinthemills.Theequipmentandthedesignwillaffectcleanlinessofthemachine.Inthenewmachineandcomponentdesignspecialemphasishasbeenputonthepreventionofbuild-upaccumulationandtakingcareoftheproblemsatthesource.Therearealsocaseswherenewequipmentisnotneededonlyrelocatingandreadjustingthecurrentisenough.Forinstanceinsomecasesrelocatinghighpressureshowersintheformingsectioncancuremistandbuildupproblems.TrainingTrainingisanessentialpartofplantingtheimprovements.Toensuregoodresultsalllevelsoftheorganizationshouldbeincludedinthetraining.Partofthetrainingisclassroomtypetrainingandpartofitishandsonatthemachine.RecordingtheResultsItisimportanttofollowupwiththeimprovementsandrecordtheresults.Thiswayitcanbemadesurethegoalsaremet.Thiswillalsohelpdeterminingwhetherfurtherstudiesincleaningmanagementareaorotherareaswillbeneeded.NEWMACHINES-CLEANINGMANAGEMENTBYDESIGNThischapterwillveryshortlyintroducesomedesignfeaturesinthenewmachinesaffectingcleaningmanagement.Withnewhighspeedmachinesthespeedaloneisnotthekeytohighproduction.Highefficiencyisneeded,whichinturniscreatedbygoodrunnabilityandminimumshutdowntime.Cleaningmanagementhasasignificantimpactonthesefactorswhichhasbeentakenintoconsiderationforexampleinthedesignofnewformer,figure3.Inthisdesignforinstanceallthewaterdrainedisdirectedintoclosedchannelshelpingtokeeptheformercleanbyavoidingsplashingandmistingonthesave-allpans.Theventilationhasevolvedfromoverallventilationintotargetventilationthuseliminatingsoilingpoints.Formingrollasthefirstdrainageelementprovideshighretention,whichenhanceswetendcleanliness.Themaindesignissuchthatmaintainingandkeepingitcleaniseasyincludingquickfabricchange.

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Figure3.Newformerdesignwithfeatureshelpingtokeepitclean.Theideaofremovingmoistureandmistatthelocation,whereitisbornisappliedalsointhenewpresssectiondesign.Inthedryersectionforinstancetheframeleghasbeendesignedtohidehydraulic,pneumaticandelectricpipingbehindacoverplate.Thatmakestheconstructionroomyandeasytokeepclean.Alsootherequipmentsuchasdryerfeltcleanersarelocatedsothatbuild-uponthemisavoided.EXAMPLESOFPROCESSIMPROVEMENTSWITHEXISTINGMACHINESIntheformingsectionhighpressureshowerscancreatemistwhichaccumulatesasbuild-uponstructures.Themistcanalsopreventvisualinspectionofthemachinewhilethemachineisrunning.Thesewillcreatebreakandsafetyhazardsunlesstakencareof.Insuchacaseamisteliminationsystemcangivegoodbenefits.AnewsprintmillinNorwayinstalledmisteliminationsystemfortopandbottomfabricwhichreducedthewetendbreaks50%,from3breaksperdayto1.5breaksperday.Withthehighspeedmachinesproducinglightergradesitisimportanttocompletethemisteliminationsystemwithfeltdryingequipment.Studieswiththepilotmachinehaveshownthatasmuchas90g/m²/sofwatercanberemovedfromthefabricwiththefabricdryingequipment.Thiswouldequal70m³/hremovedwaterona10mwidemachineinproductionrunningat22m/s（1320m/min）.Ifnotremovedthiswaterincludinge.g.fillersandfineswillpartiallygetthrownintothestructuresandaccumulatebuild-up.Asseeninfigure4thewetstreakscausedbyhighpressureshowerswillalsobeeliminatedwiththissystem,whichisimportantwithlightergradesasthesteakswillshowinthepapermoistureprofile.

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Figure4.Innerfabricconditioningsysteminformingsectionwithmistremovalandfabricdrying.Doctoringispartofthepapermachine’scleaningmanagement.Theareawithlotofpotent