冷化勘驗儀器的選定
接線盒內接線端子的防潮問題。由於鹽水溫度很可能比環境溫度低2040,連(lian)接(jie)盒(he)如(ru)果(guo)太(tai)靠(kao)近(jin)鹽(yan)水(shui)管(guan)道(dao),由(you)於(yu)熱(re)傳(chuan)導(dao)影(ying)響(xiang)可(ke)能(neng)使(shi)接(jie)線(xian)盒(he)溫(wen)度(du)大(da)大(da)低(di)於(yu)環(huan)境(jing)溫(wen)度(du),引(yin)起(qi)接(jie)線(xian)端(duan)子(zi)之(zhi)間(jian)結(jie)露(lu),導(dao)致(zhi)絕(jue)緣(yuan)下(xia)降(jiang)甚(shen)至(zhi)短(duan)路(lu),造(zao)成(cheng)溫(wen)度(du)值(zhi)偏(pian)低(di)。為(wei)了(le)避(bi)免(mian)這(zhe)個(ge)問(wen)題(ti)的(de)發(fa)生(sheng),接(jie)線(xian)盒(he)至(zhi)少(shao)應(ying)離(li)開(kai)保(bao)溫(wen)層(ceng)100mm,使接線盒溫度與環境溫度接近。
管(guan)外(wai)貼(tie)裝(zhuang)鉑(bo)熱(re)電(dian)阻(zu),有(you)一(yi)些(xie)測(ce)量(liang)對(dui)象(xiang)一(yi)年(nian)四(si)季(ji)沒(mei)機(ji)會(hui)停(ting)車(che),無(wu)法(fa)在(zai)管(guan)道(dao)上(shang)開(kai)口(kou)裝(zhuang)表(biao),隻(zhi)能(neng)用(yong)管(guan)外(wai)貼(tie)裝(zhuang)鉑(bo)熱(re)電(dian)阻(zu)的(de)測(ce)量(liang)方(fang)法(fa),因(yin)為(wei)鹽(yan)水(shui)管(guan)外(wai)壁(bi)上(shang)總(zong)是(shi)濕(shi)漉(lu)漉(lu)的(de),所(suo)以(yi)貼(tie)鉑(bo)熱(re)電(dian)阻(zu)必(bi)須(xu)有(you)防(fang)水(shui)防(fang)潮(chao)性(xing)能(neng)。熱(re)電(dian)阻(zu)與(yu)管(guan)璧(bi)之(zhi)間(jian)應(ying)有(you)良(liang)好(hao)的(de)熱(re)傳(chuan)導(dao),熱(re)電(dian)阻(zu)貼(tie)裝(zhuang)處(chu)及(ji)周(zhou)圍(wei)區(qu)域(yu)應(ying)強(qiang)化(hua)絕(jue)熱(re)保(bao)溫(wen),經(jing)過(guo)這(zhe)樣(yang)的(de)處(chu)理(li)以(yi)後(hou),鉑(bo)熱(re)電(dian)阻(zu)測(ce)到(dao)的(de)溫(wen)度(du)比(bi)管(guan)內(nei)水(shui)溫(wen)偏(pian)高(gao)的(de)數(shu)值(zhi)被(bei)限(xian)製(zhi)在(zai)0.10.2以內是完全可能的。
流量計的選型測量冷鹽水流量的儀表有很多種,電磁流量計有著明顯的優勢,下麵隻介紹一下電磁流量計。(1)測量管內襯的選擇。由於鹽水對不鏽鋼等材質都有腐蝕,在測量鹽水時,需選聚四氟乙烯內襯。(2)測量管勵磁線圈防潮問題。電磁流量計中的勵磁線圈密封在殼體的方法常用的有兩種:一種是用上下兩半外殼,用螺絲將密封條壓緊後,達到密封;另ling一yi種zhong使shi用yong殼ke體ti焊han接jie密mi封feng法fa,將jiang線xian圈quan與yu外wai界jie隔ge絕jue。其qi中zhong後hou者zhe更geng可ke靠kao,可ke完wan全quan杜du絕jue線xian圈quan空kong腔qiang的de呼hu吸xi現xian象xiang,防fang止zhi外wai界jie潮chao氣qi侵qin入ru。但dan在zai生sheng產chan過guo程cheng中zhong,線xian圈quan周zhou圍wei空kong腔qiang內nei總zong是shi充chong滿man空kong氣qi,而er其qi中zhong的de水shui汽qi含han量liang隨sui裝zhuang配pei時shi的de大da氣qi溫wen度du和he相xiang對dui濕shi度du的de變bian化hua而er變bian化hua,如ru果guo水shui汽qi含han量liang較jiao高gao,則ze流liu量liang計ji在zai投tou入ru使shi用yong後hou由you於yu導dao管guan和he空kong腔qiang中zhong溫wen度du降jiang低di,很hen可ke能neng會hui出chu現xian結jie露lu現xian象xiang,導dao致zhi線xian圈quan受shou潮chao,絕jue緣yuan被bei破po壞huai。因yin而er,在zai冷leng鹽yan水shui溫wen度du較jiao低di時shi(有的製造廠是以0為界),用氮氣將空腔中的空氣置換掉,而在溫度更低時(如-10或更低),用甲基矽油(或變壓器油)充灌,不同的製造廠做法不盡相同,但總的一條是封入的幹燥介質不會逃逸,而且在長期使用中,繞圈絕緣不會降低。
內nei襯chen承cheng受shou負fu壓ya問wen題ti。冷leng鹽yan水shui流liu量liang正zheng常chang測ce量liang時shi,測ce量liang管guan本ben身shen並bing不bu承cheng受shou負fu壓ya,隻zhi有you在zai將jiang管guan道dao中zhong的de存cun水shui排pai放fang時shi,由you於yu管guan道dao最zui高gao點dian的de放fang空kong閥fa忘wang記ji打da開kai,才cai會hui使shi管guan道dao上shang部bu出chu現xian負fu壓ya,就jiu有you可ke能neng使shi測ce量liang管guan內nei襯chen瞬shun時shi脫tuo落luo。一yi般ban電dian磁ci流liu量liang計ji廠chang家jia會hui給gei出chu內nei襯chen所suo承cheng受shou的de最zui大da管guan內nei負fu壓ya,也ye可ke以yi選xuan用yong能neng承cheng受shou負fu壓ya的de內nei襯chen,這zhe種zhong內nei襯chen由you特te殊shu設she計ji的de內nei襯chen骨gu架jia網wang而er使shi其qi能neng承cheng受shou絕jue對dui真zhen空kong的de壓ya強qiang,橫heng河he等deng公gong司si有you此ci類lei產chan品pin。http://98fo.cn



