保养您的杨克烘缸.doc

保养您的杨克烘缸86福伊特新的烘缸研磨方案确实与众不同00.0050.01.0.0150.020.0250.030.0354812162024Monthsfromprofilegrind表面发生研磨的月份LookafteryourYankeeVoithSnewgrindingprogrammecouldmakearealdifference近福伊特薄页纸烘缸服务集团开发出一种研磨扬克取赫磨方法方面进行了革新.通过将激光扫描和研磨力电脑控制相互结合,VRG能现场对烘缸表面轮廓的研磨情况建立一个快速而精确的新标准.该项技术已经引起了对杨克烘缸表面研磨设计方面的实践进行重新检测.表面轮廓维护程序(PMP)就是一个新范例.PMP$1J用其它损耗维修方案在2432小时内来完成轮廓研磨的维护.采用该方案,薄页纸厂非常满意该方法在维护性能上的可预防性.这正好与现在大多工厂的很多重要设备都被用到不能用为止的现实情况形成Pulp&PaperTechnology?纸业技术opmentbyVoithPaperSTissueCylinderofitsVirtualReferenceGrinding(VRG】trulyrevolutionisedthewayYankeeandMGcylindersareground.BycornbiningseanningIaserswithcornputerisedcontroIofqrindinqforces.theVRGhassetanewstandardforspeedandaccuracyinthearindinqofcrownedorprofiIedcylindersinthefield.ThetechnoloqvhasIeadtoareexaminationofthepracticesconcerningtheplanningofYankeeprofilegrinding.ThenewparadigmistheProfileMaintenanceProgram(PMP】_PMPtakesadvantaqeofotherplannedmaintenaneeoutaqestocompleteaprofiIemaintenaneeqrindin2432hours.Byadoptingthisprogramme.tissuecompaniesareembracingthephiIosophyofpreventivemaintenanee.ThiSiSincontrasttotheruntofailurepracticeCUrrentlyusedbymanyintheindustry.withregardtotheconditionoftheirmostimportantassets.cQcc一o一一0斟v水亲棼保养您的杨克烘缸杨克烘缸是传统薄页纸机的核心.它的辊型和轮廓非常关键,因为压榨脱水辊和杨克烘缸之间合适的几何关系由前两者确定,并且它们还承担着全冷凝负荷.杨克烘缸的表面轮廓会由于工艺过程不稳定造成的影响El积月累而退化.杨克烘缸具有自身的运行周期,这个周期是通过长时间的经验得到的.正常情况下,这个周期是指纸机产生如水分控制,边缘断纸等问题对纸机效率产生重大影响之前纸机总的正常运行时间.关注的焦点是如何尽可能的延长纸机运行时间,这样可以避免烘缸表面进行全面研磨所需的23天停机时间.典型研磨平均将磨掉o075cm厚的烘缸表层.通常工厂过高估计了在杨克烘缸表面情况恶化所产生的纸机问题点之前的纸机正常运行时间.这会导致在最后的几周甚至几个月里,纸机生产效率低,产品质量不合格.随着VRG研磨方案的诞生,辊型表面能由直接安装在现有刮刀架上BgVRG系统来研磨.这种直接安装不需要把压力辊和其它很沉的机械设备挪开.与其成鲜明对比的是,早期的切线研磨机(TG)技术必须利用重达63吨的平台床!利用VRG技术可以为工厂节省12-24dx时的前期研磨机准备工作.VRG另外的一个优势是其软件包中含有高水平的纪录技术.VRG系统能对烘缸研磨前,研磨中以及研磨后的表面情况进行全面扫描.这就使得工厂在研磨前能够正确估价烘缸的情况,以及测定任何不正常的损坏情况,这些不正常的情况可能会间接说明冷凝物去除系统或喷雾涂布系统等所存在的问题.实际经验表明杨克烘缸的磨损比和时间不呈线性关系.当压力辊和杨克烘缸之间的错位情形增加以及操作员调整刮浆刀以便应付高/低湿度区域时,磨损率将加速升高.从图中可以看出,当烘缸半径损耗超过oOl2英寸(3mm)时,磨损率将加速增加.在进行研磨操作之前的最后六个月,薄页纸厂通常要遇到更多的断纸和产品质量问题,这个问题是逐渐增加但并不持久.这段时间的效率损失对纸厂的最终经济效益会产生重大影响.由于这种磨损是逐渐增加的,因此可能一直到纸机运行受到影响以至于工厂再不能拖延所需的研磨为止才会被发现.很多工厂在延长研磨周期的最后阶段对烘缸表面施涂大量有机涂料以维持保证纸机正常运行,从而达到延长研磨周期的目的.与经研磨提高使用率相比,这里面所用的额外化学品成本能达到好几千美元/天.通过采用表面维护程序(PMP),工厂可避免抵达纸机磨损曲线的加速磨损部位.从图中可以得知,研磨时间应该在1819个月之间或稍微提前一些,而早先实际时间是24个月.实际的磨损曲线会由于每个纸机的不同而有些变化.但是,有一个规则是:需要研磨的时间大多数是历史研磨周期892/3.表中列出了采用PMP实践带来的潜在节约情况.从该事例可以看出,短周期高频率的研磨使得停机时间大大降低,除去额外的研磨成本,能净节约868;5美元(人民币6717).传统研磨周期最后3个月中由于断纸,使用化学品,纸机车速问题以及质量问题所导致的效率损失估计为每天2400美元(90天共计18617人民币).这些节约数字并不是企图把价值放在由于对杨克烘缸采用PMP使其材料留下来的额外研磨价值的节约之上由于烘缸表明金属材料磨除率降低,从而能延长杨克烘缸的使用寿命.总的来说,对您的传统杨克烘缸采用福伊特的表面维护程序(PMP),您可以充分的降低由表面研磨所引起的停机时间,避免由干燥DngTheYankeedryeristheheartoftheconventionaltissuemachine.1tscrownorprofileiscriticalwhenitcomestoestablishingthepropergeometrybetweenthepressure/dewateringrollsandtheYankeewhenitisunderafullcondensingload.TheYankeeprofiledegradesovertimeduetothecumulativeeffectofprocessupsets.Yankeeshavetypicallybeenaroundonacyclethathasbeenestablishedwithexperienceovertime.NormallYthiscyclewasbasedontheamountoftimethemathineCOUldrunbeforeproblemswithmoisturecontro1.edgebreaksandpickingmadeasignificantimpactuponthemathinesefficiency.ThefoCUSwasonextendingtheruntimeaslonqaspossibletoavoidthe2-3daysofdowntimerequiredtocompleteafullprofilegrind.Atypicalgrindremoves.onaverage,0.075cmfromtheradiusofthecylinder.0ftenm川soverestimatetheamountofruntimerequiredtogettothepointofsignificantmachineimpact,causedbypoorconditionsoftheYankeesprofile.Thjscanresultinweeksorevenmonthsofreducedpapermachjneefficiencyandoffqualityproduction.WiththedevelopmentoftheVRG,crownprofilescanbegroundbyasystemthatmountsdirectlyonanexistjngdoctorbladeholder.ThisdoctormountingelimjnatestheneedtoremovepressureroIIsandotherheavypapermachinecomponents.Thjscomparestothee仟ortsrequiredtoprepareamachineforthepreviousTangentialGrinder(TG)technologywhichusedaheavyplatformbedthatweighed6.3tonnesjAtypicalmcansave1224hoursofpreandpostgrindmathinepreparationworkwhenusingtheVRGforatypicalarind.AnotheradvantageoftheVRGjstheunparalleledlevelofdocumentationjncJudedfnthegrjndpackage.TheVRGsystemgivescompletetopographicalseansofthedryingcylinderbefore,duringandfollowingthegrind.ThisalJOWSthemtoevaluatetheconditionofthecyljnderbeforethegrjnd,todetermineanyunusuaJwearconditionswhichmjqhtindjcateaproblemwiththecondensateremovalsystemorthecoatingspraysetc.ExperiencehasshownthatthewearrateovertjmefortheYankeesurfaceisnotlineaLAsthemisscrownconditionjncreasesbetweenpressurerollsandtheYankeeandasoperatorsmakedoctorbladeadiustmentstocopewithlow/highmoistureareas.thewearrateaccelerates.AsshownjnthegraphthewearrateacceleratesastheradiaJJOSSpassesthe012jnchpojnt(3mm】jnthelowareas.Durjngtheflnalsixmonthsofoperationpriortogrindjng.thetissuemathjneusuallyexperiencesanjncreasejnbreaksandqualitvjssuesthataregraduaJbutverypersistent.EfficiencyJossesdurinathjsperiodcanhaveasignjficanteconomjcjmpactonthemsresults.DuetothegraduaJnatureofthisdegradationitmayqounnoticeduntjltheoperationofthemathjnejsaffected.totheDOintwherethemilIcannolongerputo仟theneedtogrind.Pulp&PaperTechnology?纸业技术87Current当前的6024monthcycle周期为24个月NeW新的430m0n协cycle周期为18个月18012OHourssaved节省的小时数60Increasedgrindcost增加的研磨成本Machinetime(S/hour)机械加工时间($/小时)Basedmetalsavings金属材料的节约Totaldowntimesavings总的停机节省时间0.0300.090S50,000S150,0000.0150.060$57,500$23o,哮.黪l棼豫镄0.030Efficiencysavingsinlast90daysbeforegrind研磨前最后90天里效率方面的节约金额S2,400(perday)x90(days)=216,000x3(regrinds)=S648,000I6yearsavings六年里总的节省金额错位导致的效率和质量损失,延长核心设备的生命周期.同时,您将获得FhVRGBj精确性,先进的绘图和纪录性能所带来的所有益处.通过采用这个程序,纸业公司开始实践预防性维修的理念.考虑到最重要的资产状况,这与目前造纸行业众多公司所采取的故障检修(即事后检修)形成了鲜明对比Byadoptingthisprogramme,tissuecompaniesareembracingthephilosophyofpreventivemaintenance.Thisisincontrasttotheruntofailurepracticecurrentlyusedbymanyintheindustry,withregardtotheconditionoffheirmostimportantassetsPulp&PaperTechnology?纸业技术$80,0o0$5,000$300,000$648,000州一穗嚣搿鲫唧麟ManymillsexperienceanincreaseintheamountoforganiccoatingrequiredtokeeptheirmathiBerunningweIIdurlngthefjnaIphaseoftheextendedgrindcycle.TheadditionaIcostofthischemistrycanrunintoseveraIthousandsofdollarsperdaywhencornparedtousageratesjustfollowingthegrind.ByadoptingaProfileMaintenanceProgram(PMP】IthemilIcanavoidreachingtheacceleratedportionofjtsmathiBe.Swearcurve.Intheexampiefromthegraph.agrindisindicatedatorbefore1819months.versusthepreviouspracticeof24months.Theactua1wearcuryevariesforeachmachiBe.ButaruIeofthumbisthatagrindismostIikelyindicatedatthetwothirdspointofthehistoricaIgrindcycleforeachmachiBe.ThetablegivesanexampieofthepotentiaIsavingsfromadoptingPMPpractices.MorefrequentgrindsofashorterdurationresuItinsignificantlyreduceddowntimeoverthesampieperiod.Anetsavingof$868.O00(RMB:6.7billion】indowntimefminusadditionaIgrindcost