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), 如(ru)不(bu)暢(chang)通(tong)應(ying)清(qing)洗(xi)使(shi)之(zhi)暢(chang)通(tong)。軸(zhou)承(cheng)損(sun)壞(huai)或(huo)轉(zhuan)動(dong)受(shou)阻(zu),軸(zhou)承(cheng)內(nei)缺(que)油(you)或(huo)軸(zhou)承(cheng)內(nei)有(you)汙(wu)垢(gou)較(jiao)多(duo)而(er)引(yin)起(qi)摩(mo)擦(ca)阻(zu)力(li)增(zeng)大(da),電(dian)機(ji)達(da)不(bu)到(dao)額(e)定(ding)轉(zhuan)速(su),應(ying)及(ji)時(shi)清(qing)洗(xi)或(huo)更(geng)換(huan)軸(zhou)承(cheng)。整(zheng)流(liu)子(zi)表(biao)麵(mian)有(you)一(yi)層(ceng)氧(yang)化(hua)物(wu),甚(shen)至(zhi)燒(shao)成(cheng)凹(ao)凸(tu)不(bu)平(ping)或(huo)電(dian)刷(shua)與(yu)整(zheng)流(liu)子(zi)外(wai)緣(yuan)不(bu)吻(wen)合(he)也(ye)可(ke)使(shi)轉(zhuan)速(su)下(xia)降(jiang),應(ying)清(qing)理(li)整(zheng)流(liu)子(zi)及(ji)電(dian)刷(shua),使(shi)其(qi)接(jie)觸(chu)良(liang)好(hao)。如(ru)轉(zhuan)子(zi)線(xian)圈(quan)中(zhong)短(duan)路(lu)或(huo)斷(duan)路(lu),可(ke)用(yong)萬(wan)用(yong)表(biao)檢(jian)查(zha),重(zhong)新(xin)繞(rao)製(zhi)線(xian)圈(quan)。轉(zhuan)子(zi)在(zai)使(shi)用(yong)時(shi)可(ke)因(yin)金(jin)屬(shu)疲(pi)勞(lao)、超速、過應力、化學腐蝕、選擇不當、shiyongzhongzhuantoubupinghengjiwendushikongdengyuanyinerdaozhilixinguanpolie,yangpinshenlou,zhuanzisunhuai。duiyuyishangqingkuangzhuyaoyaoqiucaozuozheshulianzhangwocaozuochengxu,zhengquexuanyongheshidelixinguanhelixinzhuanzi,zhuyiyangekongzhimeiyibucaozuocaoxu,jinliangjianshaorenweidebubiyaodesunshang,zaizhuanzideanquanxishujibaozhengqineishiyong。
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、響xiang聲sheng異yi常chang。以yi上shang原yuan因yin大da部bu分fen均jun係xi不bu正zheng確que操cao作zuo所suo致zhi,在zai找zhao出chu原yuan因yin後hou,正zheng確que操cao作zuo即ji可ke消xiao除chu不bu正zheng常chang現xian象xiang。在zai工gong作zuo過guo程cheng中zhong,如ru出chu現xian任ren何he異yi常chang現xian象xiang均jun應ying立li即ji停ting機ji, 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su。zhuanzishoudaogaowenshi。zhuanzidebaoyangzhuanzizaimeicishiyongqianyaoyangejianzhakongneishifouyouyiwuhewugou,yibaochipingheng。zhuanzibixubaochiganzaoqingjie,qiewupengzhuangcashang。rubushenshiluo,yingduizhuanzijinxingX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℃zuoyou,yekejiangzhuanzifangzaibingxiangzhongyulengshuxiaoshibeiyong,lixinbeikezhijiecunfangzaibingxiangzhongyuleng。lixinzhongdeyichangxianxiangzailixinguochengzhong,rufaxianbuzhengchangzaoyinjizhendonglijitingjijianzha,weizhaochuyuanyinqianbudejixuyunzhuan。zhujibaoyangsangeyueyingduizhujixiaozhengyicishuipingdu。meishiyong5億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ji1—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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