粒度控制技术

粒度控制技术Problemsofvariableproductqualitywerebeingexperiencedwithapharmaceuticalmill.Materialwasfedtothemillbyarotaryvalve,andgroundusingturbulentairjets.Groundmaterialexitedviathedynamicclassifier.变产品质量问题，正在经历了一个制药工厂。材料送入轧机由一个旋转阀，空气和地面用湍流射流。飞离地面材料通过动态分类。CLnsbiJItrPeriodicsamplingoftheproducttookplaceatafixedperiodofDt.Samplesmeasuredinthiswayshowedtheprocesstobeacceptablyclosetothesetpoint.定期抽样的产品发生在了D吨固定期间举行样品测定结果显示，这样的进程是可以接受的接近设定值。However,whenreal-timeparticlesizemeasurementswereundertaken,usinganInsitecontheoutletofthemill,themillwasrevealedtobemuchless

stable.但是，当实时测量颗粒大小进行了使用在该工厂出口一Insitec，该厂被透露给少了很多稳定。Thegraphbelowshowsthatthemediansize(Dv50)(redline)fluctuatessignificantly.Thiscorrespondstoaperiodicfluctuationinthemeasuredtransmission(blueline),whichisrelatedtothemillloading.100%transmissioncorrespondstotherebeingnoparticlespresent,and0%meansthatsomanyarepresentthatnolightisreachingthedetector.下面的图显示大小的中位数（的DV50）（红色线）波动明显。这相当于在测量传输（蓝线），这是关系到工厂装货的周期性波动。100%的传输对应无人有颗粒的，和0%意味着有这么多在场，没有光到达探测器。TimefromStart(s)Periodicfluctuationsthataretheconsequenceofforcingmaterialthroughthemill,leadto"short-circuiting"oftheclassifier.ThisaffectstheDv50oftheparticles.Thehighertheloading,themorepronouncedistheeffect,resultinginalarger(coarser)mediansize.Asmoreandmoreparticlesareforcedthroughtheclassifier,theclassifiermotordrawsmoreandmorecurrent(greenline).Theremedytothissituationwastousethemeasuredtransmissionvaluetodrivethefeedrotaryvalve.周期波动是通过强迫磨材料的后果，导致'短路的量词〃。这影响到粒子的DV50。载入越高，就越是突出的效果，造成了更大的(粗)中位数的大小。随着越来越多的颗粒分级机强行通过，吸引更多的分类汽车和更多的电流(绿线)。情况对症下药，这是利用实测传输值，以推动饲料旋转阀。Asaresulttransmissionoscillatesaroundameanvalue(indicativeofasimplecontrolscheme)andcriticallythemediansizeiscontinuallyclosetothesetpoint.因此传输围绕均