在(zai)使(shi)用(yong)過(guo)程(cheng)中(zhong)經(jing)常(chang)出(chu)現(xian)電(dian)機(ji)不(bu)能(neng)起(qi)動(dong)的(de)現(xian)象(xiang),如(ru)主(zhu)電(dian)源(yuan)指(zhi)示(shi)燈(deng)亮(liang),這(zhe)時(shi)應(ying)檢(jian)查(zha)炭(tan)刷(shua)磨(mo)損(sun)程(cheng)度(du),如(ru)炭(tan)刷(shua)磨(mo)損(sun)超(chao)過(guo)總(zong)量(liang)的(de)三(san)分(fen)之(zhi)一(yi),應(ying)及(ji)時(shi)更(geng)換(huan)新(xin)的(de)炭(tan)刷(shua)。主(zhu)電(dian)源(yuan)指(zhi)示(shi)燈(deng)不(bu)亮(liang)時(shi),檢(jian)查(zha)指(zhi)示(shi)燈(deng)保(bao)險(xian)絲(si)及(ji)室(shi)內(nei)配(pei)電(dian)板(ban)保(bao)險(xian)絲(si)是(shi)否(fou)熔(rong)斷(duan),同(tong)時(shi)檢(jian)查(zha)電(dian)源(yuan)線(xian)是(shi)否(fou)接(jie)觸(chu)良(liang)好(hao),如(ru)保(bao)險(xian)絲(si)斷(duan)則(ze)應(ying)更(geng)換(huan)保(bao)險(xian)絲(si)並(bing)保(bao)持(chi)電(dian)路(lu)暢(chang)通(tong)。還(hai)應(ying)檢(jian)查(zha)真(zhen)空(kong)泵(beng)表(biao)及(ji)油(you)壓(ya)指(zhi)示(shi)值(zhi),如(ru)油(you)壓(ya)過(guo)高(gao)而(er)主(zhu)機(ji)也(ye)不(bu)能(neng)啟(qi)動(dong),必(bi)須(xu)檢(jian)查(zha)各(ge)油(you)路(lu)是(shi)否(fou)堵(du)塞(sai),特(te)別(bie)是(shi)節(jie)流(liu)小(xiao)孔(kong)是(shi)否(fou)暢(chang)通(tong), rubuchangtongyingqingxishizhichangtong。zhouchengsunhuaihuozhuandongshouzu,zhouchengneiqueyouhuozhouchengneiyouwugoujiaoduoeryinqimocazulizengda,dianjidabudaoedingzhuansu,yingjishiqingxihuogenghuanzhoucheng。zhengliuzibiaomianyouyicengyanghuawu,shenzhishaochengaotubupinghuodianshuayuzhengliuziwaiyuanbuwenheyekeshizhuansuxiajiang,yingqinglizhengliuzijidianshua,shiqijiechulianghao。ruzhuanzixianquanzhongduanluhuoduanlu,keyongwanyongbiaojianzha,zhongxinraozhixianquan。zhuanzizaishiyongshikeyinjinshupilao、超速、過應力、化學腐蝕、選擇不當、使shi用yong中zhong轉zhuan頭tou不bu平ping衡heng及ji溫wen度du失shi控kong等deng原yuan因yin而er導dao致zhi離li心xin管guan破po裂lie,樣yang品pin滲shen漏lou,轉zhuan子zi損sun壞huai。對dui於yu以yi上shang情qing況kuang主zhu要yao要yao求qiu操cao作zuo者zhe熟shu練lian掌zhang握wo操cao作zuo程cheng序xu,正zheng確que選xuan用yong合he適shi的de離li心xin管guan和he離li心xin轉zhuan子zi,注zhu意yi嚴yan格ge控kong製zhi每mei一yi步bu操cao作zuo操cao序xu,盡jin量liang減jian少shao人ren為wei的de不bu必bi要yao的de損sun傷shang,在zai轉zhuan子zi的de安an全quan係xi數shu及ji保bao證zheng期qi內nei使shi用yong。
電dian源yuan不bu通tong是shi導dao致zhi冷leng凍dong機ji啟qi動dong及ji製zhi冷leng效xiao果guo差cha的de原yuan因yin之zhi一yi,與yu電dian機ji不bu轉zhuan的de故gu障zhang相xiang同tong,應ying分fen別bie檢jian查zha電dian源yuan及ji保bao險xian絲si。電dian壓ya過guo低di,安an全quan裝zhuang置zhi故gu障zhang也ye可ke使shi冷leng凍dong機ji不bu能neng啟qi動dong,電dian壓ya過guo低di可ke能neng是shi電dian網wang電dian壓ya低di;配電板配線過多;電源線過長理想長度為3米等。電源線容量不夠,不僅使電壓降低,還會造成意外事故。當電源電壓降到180 —190VJ時(shi),冷(leng)凍(dong)機(ji)不(bu)能(neng)啟(qi)動(dong),影(ying)響(xiang)製(zhi)冷(leng)效(xiao)果(guo)。通(tong)風(feng)性(xing)能(neng)不(bu)好(hao),如(ru)儀(yi)器(qi)安(an)裝(zhuang)在(zai)日(ri)光(guang)直(zhi)射(she)或(huo)通(tong)風(feng)不(bu)良(liang)處(chu),散(san)熱(re)器(qi)效(xiao)果(guo)差(cha),或(huo)散(san)熱(re)器(qi)蓋(gai)滿(man)灰(hui)塵(chen),也(ye)中(zhong)會(hui)影(ying)響(xiang)製(zhi)冷(leng)效(xiao)果(guo)。離(li)心(xin)管(guan)重(zhong)量(liang)不(bu)平(ping)衡(heng),放(fang)置(zhi)不(bu)對(dui)稱(cheng);轉子孔內有異物,使負荷不平衡;轉軸上端固定螺帽鬆動,轉軸磨擦或彎曲;電機轉子不在磁場中心會產生噪音;轉子本身損傷等都可導致機體震動劇烈、xiangshengyichang。yishangyuanyindabufenjunxibuzhengquecaozuosuozhi,zaizhaochuyuanyinhou,zhengquecaozuojikexiaochubuzhengchangxianxiang。zaigongzuoguochengzhong,ruchuxianrenheyichangxianxiangjunyinglijitingji, 不得強行運轉,以免產生不必要的損失。
下麵簡介離心機的維護及注意事項:
離心機的安裝應根據離心機的性能選擇合作的地點放置,對一般低速離心機台式可放在平穩、堅固的台麵上 它的底座都裝有橡皮吸腳,借助於大氣力壓力及儀器本身的重量,緊貼於台麵;大da容rong量liang低di速su離li心xin機ji和he高gao速su離li心xin機ji和he高gao速su冷leng凍dong離li心xin機ji要yao相xiang應ying地di安an放fang在zai堅jian實shi的de地di麵mian上shang,水shui平ping放fang置zhi。超chao速su離li心xin機ji重zhong達da數shu百bai公gong斤jin,應ying放fang在zai很hen堅jian實shi的de地di麵mian上shang並bing有you防fang塵chen、防fang潮chao設she備bei,保bao證zheng離li心xin室shi達da到dao一yi定ding的de真zhen空kong度du,正zheng常chang運yun行xing。選xuan擇ze合he適shi的de轉zhuan頭tou離li心xin機ji工gong作zuo前qian,應ying將jiang負fu荷he平ping衡heng,重zhong量liang誤wu差cha越yue小xiao越yue好hao,否fou則ze會hui引yin起qi劇ju烈lie震zhen動dong,損sun壞huai離li心xin轉zhuan子zi及ji轉zhuan軸zhou。離li心xin器qi支zhi架jia離li心xin器qi分fen離li支zhi架jia必bi需xu安an置zhi離li心xin管guan後hou運yun作zuo,嚴yan禁jin空kong架jia運yun轉zhuan。離li心xin機ji啟qi動dong時shi,轉zhuan速su開kai關guan或huoG值旋鈕放在低擋位,啟動後再逐步調節到所需要的數值。一次工作後,再將旋鈕調至低擋位再次工作,在高轉速或G擋(dang)禁(jin)止(zhi)直(zhi)接(jie)啟(qi)動(dong)。轉(zhuan)子(zi)的(de)最(zui)高(gao)轉(zhuan)速(su)在(zai)下(xia)述(shu)情(qing)況(kuang)下(xia)要(yao)降(jiang)低(di)轉(zhuan)子(zi)的(de)最(zui)高(gao)轉(zhuan)速(su)轉(zhuan)子(zi)的(de)運(yun)轉(zhuan)時(shi)間(jian)和(he)運(yun)轉(zhuan)次(ci)數(shu)達(da)到(dao)規(gui)定(ding)的(de)壽(shou)命(ming)時(shi)。當(dang)轉(zhuan)子(zi)受(shou)到(dao)局(ju)部(bu)表(biao)麵(mian)損(sun)傷(shang)或(huo)出(chu)現(xian)管(guan)孔(kong)內(nei)輕(qing)微(wei)腐(fu)蝕(shi)時(shi)。使(shi)用(yong)不(bu)鏽(xiu)鋼(gang)離(li)心(xin)管(guan)、套管、厚壁管或離心瓶時。樣品平均密度超過1.2g/cm3時,其實用轉速N為:
,其中N 為實用轉速,N 為最大轉速su。轉zhuan子zi受shou到dao高gao溫wen時shi。轉zhuan子zi的de保bao養yang轉zhuan子zi在zai每mei次ci使shi用yong前qian要yao嚴yan格ge檢jian查zha孔kong內nei是shi否fou有you異yi物wu和he汙wu垢gou,以yi保bao持chi平ping衡heng。轉zhuan子zi必bi需xu保bao持chi幹gan燥zao清qing潔jie,切qie勿wu碰peng撞zhuang擦ca傷shang。如ru不bu慎shen失shi落luo,應ying對dui轉zhuan子zi進jin行xingX光拍片檢查,確認無內部損傷後方可使用。離心管離心管可由許多種不同材料製成,如聚乙烯PE、纖維素CAB、聚碳酸脂PC、聚丙烯PP等。各種離心管的拉力強度和伸長度都不同,應按需要選用。注意保證樣品、溶劑及梯度材料不腐蝕離心管及蓋組件過期、老化、有you裂lie紋wen或huo已yi受shou腐fu蝕shi的de離li心xin管guan盡jin量liang不bu用yong或huo降jiang速su使shi甩shuai控kong製zhi塑su料liao離li心xin管guan的de使shi用yong次ci數shu,注zhu意yi規gui格ge配pei套tao。離li心xin過guo程cheng中zhong不bu得de不bu開kai啟qi離li心xin室shi蓋gai,不bu得de用yong手shou或huo異yi物wu碰peng撞zhuang正zheng在zai旋xuan轉zhuan中zhong的de轉zhuan子zi及ji離li心xin管guan。低di溫wen離li心xin樣yang品pin應ying先xian將jiang空kong的de轉zhuan子zi2000r/min預冷一定時間,預冷時控製溫度在0℃左(zuo)右(you),也(ye)可(ke)將(jiang)轉(zhuan)子(zi)放(fang)在(zai)冰(bing)箱(xiang)中(zhong)預(yu)冷(leng)數(shu)小(xiao)時(shi)備(bei)用(yong),離(li)心(xin)杯(bei)可(ke)直(zhi)接(jie)存(cun)放(fang)在(zai)冰(bing)箱(xiang)中(zhong)預(yu)冷(leng)。離(li)心(xin)中(zhong)的(de)異(yi)常(chang)現(xian)象(xiang)在(zai)離(li)心(xin)過(guo)程(cheng)中(zhong),如(ru)發(fa)現(xian)不(bu)正(zheng)常(chang)噪(zao)音(yin)及(ji)振(zhen)動(dong)立(li)即(ji)停(ting)機(ji)檢(jian)查(zha),未(wei)找(zhao)出(chu)原(yuan)因(yin)前(qian)不(bu)得(de)繼(ji)續(xu)運(yun)轉(zhuan)。主(zhu)機(ji)保(bao)養(yang)三(san)個(ge)月(yue)應(ying)對(dui)主(zhu)機(ji)校(xiao)正(zheng)一(yi)次(ci)水(shui)平(ping)度(du)。每(mei)使(shi)用(yong)5億轉處理真空泵油一次,工作500小時應檢查驅動電機炭刷,最好用吸塵器將摩擦產生的炭粉除去,必要時需要更換炭刷或將整流子用細砂紙打光。每使用1500小(xiao)時(shi)左(zuo)右(you)應(ying)清(qing)洗(xi)驅(qu)動(dong)部(bu)位(wei)軸(zhou)承(cheng)並(bing)四(si)高(gao)速(su)潤(run)滑(hua)脂(zhi),轉(zhuan)軸(zhou)與(yu)轉(zhuan)子(zi)接(jie)合(he)部(bu)應(ying)經(jing)常(chang)塗(tu)脂(zhi)防(fang)鏽(xiu),長(chang)期(qi)不(bu)用(yong)時(shi)應(ying)塗(tu)防(fang)鏽(xiu)油(you)加(jia)油(you)紙(zhi)包(bao)紮(zha)。平(ping)時(shi)不(bu)用(yong)時(shi),應(ying)每(mei)月(yue)低(di)速(su)成(cheng)開(kai)機(ji)1—2次,每次半小時,保證各部位的正常運轉。前麵已經談到離心轉子的種類很多,形狀不一, 對於彼此之間離心半徑的換算比較麻煩,為此提出了離心轉頭的K因素法, 使各種離心轉子間的換算簡化。
將沉將係數
,進行微分得,S=dlnxl /w2t.通常離心沉降由最小半徑a到最大半徑b, 則S=Inb/a/W 2dt,設1nb/a/W2=K,T=dt得S=K/T由上式可以算出每種轉子在不同轉速時的K值,列成一個K值表。實驗時如需要改變離心轉速,隻要查出相應的轉速的K值,然後根據S=K/T,就可以算出改變轉速後應該離心的時間。如原來選用轉速成的K值為K .其離心時間T1,今要改用另一轉速離心,隻須由表中查出其相應K值,如K 2由於樣品的沉降係數S是一定的,故有S=K1/T1=K 2/T 2可以算出K2時的T 2, 從上式可以看出, 對於同類轉子其K值反映了轉子的離心能力,K值越小,離心能力越大,離心時間越短, 轉子使用價值越高。
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