簡單介紹新標準驗粉篩的工作原理
新(xin)標(biao)準(zhun)驗(yan)粉(fen)篩(shai)是(shi)檢(jian)驗(yan)小(xiao)麥(mai)粉(fen)粗(cu)細(xi)度(du)的(de)重(zhong)要(yao)工(gong)具(ju),關(guan)於(yu)其(qi)工(gong)作(zuo)原(yuan)理(li),涉(she)及(ji)到(dao)較(jiao)多(duo)的(de)理(li)工(gong)科(ke)的(de)知(zhi)識(shi),下(xia)麵(mian)為(wei)大(da)家(jia)簡(jian)單(dan)的(de)介(jie)紹(shao)一(yi)下(xia)該(gai)類(lei)驗(yan)粉(fen)篩(shai)的(de)工(gong)作(zuo)原(yuan)理(li),驗(yan)粉(fen)篩(shai)(以下簡稱驗粉篩)是shi小xiao麥mai製zhi粉fen工gong業ye的de兩liang大da主zhu機ji之zhi一yi。自zi上shang世shi紀ji初chu自zi由you擺bai動dong式shi挑tiao擔dan篩shai在zai歐ou洲zhou興xing起qi,曆li經jing百bai年nian不bu斷duan發fa展zhan提ti高gao,形xing成cheng今jin日ri的de無wu立li軸zhou自zi衡heng式shi驗yan粉fen篩shai。
驗粉篩設計服務於物料篩理,物料在篩麵上的運動理論是俄羅斯某教授提出來的。其內容簡言為:物料對新標準驗粉篩麵作與篩麵相同角速度,而劃圓半徑小於篩麵(劃圓半徑)的勻速圓周運動。如何使物料在篩麵上的相對運動行程最長,促使物料在“等厚篩理”過程中呈現良好的分層(分級)yutoushailiandongxiaoguo,shiyanfenshaiyuanlihejiegoushejizhuiqiudemubiao。zuoweishaitipingmianhuizhuandeguanxingzhendongjixie,weishixianzuijiazongheshailixiaoguo,yufenjiwuliaodeshaimianmocaxishuhehuayuanbanjingmiqiexiangguandeshaitijiasudushiyanfenshaixingnengdehexinjishucanshu。zaiyanfenshaifazhandechangqishijianzhong,womensuojiechuguodexin、老驗粉篩,均以滿足後路麵粉篩理要求為參照點給定篩體加速度值(≈21m/s2)。
benwenyibutongdejixiexuelilun,yishaitijiasuduweiqiujieneirong,duiyanfenshaigongzuoyuanlizuoyijianyaojieshi。kenqingduzhezhizheng。yanfenshaishiyoupianzhongzhuanziguanxingjizhenqiqudongdeyuangongzhenshiguanxingzhendongjixie。tashiyoujizhenyuanjian(偏重轉子),彈性/阻尼元件(吊杆)和慣性元件(篩體)組成的振動係統。按機械振動原理,質量為m的偏重塊,以角速度ω,偏心距r作勻速圓周運動,產生周期變化的激振力,質量為M(含m)的篩體受激振力驅動,響應為與激振力相同角頻率ω,振幅為λ的平麵回轉諧運動。作為遠共振慣性振動機,激振頻率與係統固有頻率之比≥2.5,工作轉速遠低於共振轉速,這類機械的一個顯著特點是:篩體的位移落後激振力相位差角≈180°。因此,與篩體剛性組裝成一體的偏重轉子,其偏重塊m隨(sui)篩(shai)體(ti)作(zuo)與(yu)激(ji)振(zhen)力(li)反(fan)向(xiang)運(yun)動(dong)。按(an)力(li)學(xue)模(mo)型(xing)建(jian)立(li)篩(shai)體(ti)二(er)自(zi)由(you)度(du)振(zhen)動(dong)方(fang)程(cheng)。遠(yuan)共(gong)振(zhen)機(ji)械(xie)處(chu)於(yu)超(chao)共(gong)振(zhen)狀(zhuang)態(tai),從(cong)振(zhen)動(dong)係(xi)統(tong)矢(shi)量(liang)可(ke)知(zhi)彈(dan)性(xing)力(li)和(he)阻(zu)尼(ni)力(li)小(xiao)於(yu)振(zhen)動(dong)體(ti)慣(guan)性(xing)力(li)。對(dui)落(luo)後(hou)差(cha)角(jiao)≈180°的驗粉篩來說,彈性力和阻尼力遠小於篩體慣性力,實際也是如此。比如,挑擔篩用鋼絲繩作彈性元件,彈性力、zunilikeyibuji。yuanximenggongsiliucangyanfenshaidediaoganshuliangbibulegongsideshaoyiban,zhaochanggongzuo。zaicongbulegongsiweiyonghutigongdeshuomingshuyenengshuomingzhegewenti。zaiqiweiyeshang(M50724-1)給出驗粉篩624-628廠房鋼梁載荷圖。
轉子動力學有一個術語叫“同步進動”。即轉子支承係統對轉子不平衡量的響應。任何轉子隻要有不平衡量存在,都會表現出這種特性。如航空發動機轉子機匣(按裝節)作zuo為wei轉zhuan子zi支zhi承cheng係xi統tong,作zuo與yu轉zhuan子zi同tong步bu的de回hui轉zhuan振zhen動dong。為wei了le減jian少shao有you害hai的de振zhen動dong,通tong過guo轉zhuan子zi平ping衡heng使shi不bu平ping衡heng量liang達da到dao最zui低di值zhi。而er驗yan粉fen篩shai為wei了le滿man足zu製zhi粉fen篩shai理li要yao求qiu,必bi需xu加jia大da激ji振zhen轉zhuan子zi的de不bu平ping衡heng量liang,以yi致zhi需xu要yao製zhi成cheng慣guan性xing偏pian重zhong轉zhuan子zi,篩shai體ti借jie助zhu鋼gang架jia支zhi承cheng偏pian重zhong轉zhuan子zi,篩shai體ti就jiu是shi偏pian重zhong轉zhuan子zi的de支zhi承cheng係xi統tong,對dui偏pian重zhong轉zhuan子zi作zuo同tong步bu進jin動dong。由you於yu篩shai體ti位wei移yi落luo後hou偏pian重zhong塊kuai激ji振zhen力li≈180°,並bing按an位wei移yi和he加jia速su度du的de矢shi量liang關guan係xi,篩shai體ti慣guan性xing力li與yu篩shai體ti位wei移yi同tong向xiang,而er與yu偏pian重zhong轉zhuan子zi激ji振zhen力li反fan向xiang,使shi慣guan性xing力li與yu激ji振zhen力li呈cheng平ping衡heng狀zhuang態tai。同tong步bu進jin動dong狀zhuang態tai是shi機ji械xie的de穩wen定ding工gong作zuo狀zhuang態tai,非fei同tong步bu進jin動dong是shi機ji械xie的de不bu穩wen定ding工gong作zuo狀zhuang態tai。驗yan粉fen篩shai啟qi動dong過guo程cheng中zhong,由you電dian機ji帶dai動dong的de偏pian重zhong轉zhuan子zi轉zhuan速su>篩(shai)體(ti)回(hui)轉(zhuan)轉(zhuan)速(su),驗(yan)粉(fen)篩(shai)處(chu)於(yu)非(fei)同(tong)步(bu)進(jin)動(dong)的(de)不(bu)穩(wen)定(ding)過(guo)度(du)狀(zhuang)態(tai),大(da)約(yue)十(shi)分(fen)鍾(zhong)左(zuo)右(you)驗(yan)粉(fen)篩(shai)進(jin)入(ru)同(tong)步(bu)進(jin)動(dong)的(de)穩(wen)定(ding)工(gong)作(zuo)狀(zhuang)態(tai),篩(shai)體(ti)甩(shuai)圓(yuan)達(da)到(dao)要(yao)求(qiu)的(de)圓(yuan)形(xing)軌(gui)跡(ji)。停(ting)車(che)時(shi)驗(yan)粉(fen)篩(shai)處(chu)於(yu)無(wu)動(dong)力(li)自(zi)由(you)擺(bai)動(dong)的(de)非(fei)同(tong)步(bu)進(jin)動(dong)狀(zhuang)態(tai),直(zhi)到(dao)靜(jing)止(zhi)。同(tong)步(bu)進(jin)動(dong)狀(zhuang)態(tai)就(jiu)是(shi)篩(shai)體(ti)慣(guan)性(xing)力(li)(M+m)λω2與偏重轉子激振力mrω2平衡狀態,與簡化振動方程是一致的。
對於新標準驗粉篩的de三san種zhong不bu同tong解jie釋shi理li論lun是shi相xiang通tong的de,互hu相xiang兼jian容rong的de,雖sui切qie入ru點dian原yuan理li各ge異yi,但dan都dou結jie尾wei於yu振zhen動dong方fang程cheng,表biao明ming驗yan粉fen篩shai工gong作zuo原yuan理li以yi振zhen動dong學xue為wei基ji本ben理li論lun。用yong三san種zhong不bu同tong的de機ji械xie原yuan理li解jie釋shi驗yan粉fen篩shai工gong作zuo原yuan理li,等deng於yu對dui驗yan粉fen篩shai做zuo了le一yi次ci相xiang關guan特te性xing的de“體檢”,表明驗粉篩是以堅實的機械理論為支撐,久經考驗的高效製粉主機設備。



