測量氣體成分的流程分析儀表。在很多生產過程中，特別是在存在化學反應的生產過程中，僅僅根據溫度、壓力
、流量等物理參數進行自動控製常常是不夠的。例如，在合成氨生產中，僅控製合成塔的溫度、壓力、流liu量liang並bing不bu能neng保bao證zheng最zui高gao的de合he成cheng率lv，必bi須xu同tong時shi分fen析xi進jin氣qi的de化hua學xue成cheng分fen，控kong製zhi氫qing氣qi和he氮dan氣qi的de最zui佳jia比bi例li，才cai能neng獲huo得de較jiao高gao的de生sheng產chan率lv。又you如ru在zai鍋guo爐lu的de燃ran燒shao控kong製zhi中zhong除chu需xu控kong製zhi燃ran料liao與yu助zhu燃ran空kong氣qi的de比bi例li外wai
，還hai必bi須xu在zai線xian分fen析xi煙yan道dao的de化hua學xue成cheng分fen，據ju此ci改gai變bian助zhu燃ran空kong氣qi的de供gong給gei量liang，使shi爐lu子zi獲huo得de最zui高gao的de熱re效xiao率lv。此ci外wai
，在zai排pai出chu有you害hai氣qi體ti的de工gong廠chang中zhong
，也ye必bi須xu采cai用yong氣qi體ti分fen析xi儀yi對dui有you害hai氣qi體ti進jin行xing連lian續xu監jian視shi，以yi防fang止zhi危wei害hai工gong人ren健jian康kang或huo汙wu染ran環huan境jing或huo引yin起qi爆bao炸zha等deng惡e性xing事shi故gu。由you於yu被bei分fen析xi氣qi體ti的de千qian差cha萬wan別bie和he分fen析xi原yuan理li的de多duo種zhong多duo樣yang，氣qi體ti分fen析xi儀yi的de種zhong類lei繁fan多duo。常chang用yong的de有you熱re導dao式shi氣qi體ti分fen析xi儀yi、電化學式氣體分析儀和紅外線吸收式分析儀等。

1、熱導式氣體分析儀
　　yizhongwulileideqitifenxiyibiao。tagenjubutongqitijuyoubutongrechuandaonenglideyuanli，tongguocedinghunheqitidaorexishulaituisuanqizhongmouxiezufendehanliang。zhezhongfenxiyibiaojiandankekao,適用的氣體種類較多,shiyizhongjibendefenxiyibiao。danzhijieceliangqitidedaorexishubijiaokunnan，suoyishijishangchangbaqitidaorexishudebianhuazhuanhuanweidianzudebianhua，zaiyongdianqiaolaiceding。redaoshiqitifenxiyidereminyuanjianzhuyaoyoubandaotiminganyuanjianhejinshudianzusilianglei。bandaotiminganyuanjiantijixiao

、熱慣性小，電阻溫度係數大,所以靈敏度高,時間滯後小。在鉑線圈上燒結珠形金屬氧化物作為敏感元件，再在內電阻、發熱量均相等的同樣鉑線圈上繞結對氣體無反應的材料作為補償用元件（圖1）。zheliangzhongyuanjianzuoweiliangbigouchengdianqiaodianlu，jishicelianghuilu。bandaotijinshuyanghuawuminganyuanjianxifubeiceqitishi
，diandaolvheredaolvjifashengbianhua
，yuanjiandesanrezhuangtaiyesuizhibianhua。yuanjianwendubianhuashiboxianquandedianzubianhua，dianqiaosuiyouyibupinghengdianyashuchu，jucikejianceqitidenongdu。redaoshiqitifenxiyideyingyongfanweihenguang，chutongchangyonglaifenxiqingqi、氨氣、二氧化碳、二氧化硫和低濃度可燃性氣體含量外
，還可作為色譜分析儀中的檢測器用以分析其他成分。

2、電化學式氣體分析儀
　　一yi種zhong化hua學xue類lei的de氣qi體ti分fen析xi儀yi表biao。它ta根gen據ju化hua學xue反fan應ying所suo引yin起qi的de離li子zi量liang的de變bian化hua或huo電dian流liu變bian化hua來lai測ce量liang氣qi體ti成cheng分fen。為wei了le提ti高gao選xuan擇ze性xing
，防fang止zhi測ce量liang電dian極ji表biao麵mian沾zhan汙wu和he保bao持chi電dian解jie液ye性xing能neng，一yi般ban采cai用yong隔ge膜mo結jie構gou。常chang用yong的de電dian化hua學xue式shi分fen析xi儀yi有you定ding電dian位wei電dian解jie式shi和he伽jia伐fa尼ni電dian池chi式shi兩liang種zhong。定ding電dian位wei電dian解jie式shi分fen析xi儀yi（圖2）的(de)工(gong)作(zuo)原(yuan)理(li)是(shi)在(zai)電(dian)極(ji)上(shang)施(shi)加(jia)特(te)定(ding)電(dian)位(wei)，被(bei)測(ce)氣(qi)體(ti)在(zai)電(dian)極(ji)表(biao)麵(mian)就(jiu)產(chan)生(sheng)電(dian)解(jie)作(zuo)用(yong)，隻(zhi)要(yao)測(ce)量(liang)加(jia)在(zai)電(dian)極(ji)上(shang)的(de)電(dian)位(wei)，即(ji)可(ke)確(que)定(ding)被(bei)測(ce)氣(qi)體(ti)特(te)有(you)的(de)電(dian)解(jie)電(dian)位(wei)
，從(cong)而(er)使(shi)儀(yi)表(biao)具(ju)有(you)選(xuan)擇(ze)識(shi)別(bie)被(bei)測(ce)氣(qi)體(ti)的(de)能(neng)力(li)。伽(jia)伐(fa)尼(ni)電(dian)池(chi)式(shi)分(fen)析(xi)儀(yi)（圖3）shijiangtouguogemoerkuosandaodianjieyezhongdebeiceqitidianjie，celiangsuoxingchengdedianjiedianliu，jiunengquedingbeiceqitidenongdu。tongguoxuanzebutongdedianjicailiaohedianjieyelaigaibiandianjibiaomiandeneibudianyacongershixianduijuyoubutongdianjiedianweideqitidexuanzexing。

 3、紅外線吸收式分析儀
　　根據不同組分氣體對不同波長的紅外線具有選擇性吸收的特性而工作的分析儀表。測量這種吸收光譜可判別出氣體的種類
；celiangxishouqiangdukequedingbeiceqitidenongdu。hongwaixianfenxiyideshiyongfanweikuan，bujinkefenxiqitichengfen
，yekefenxirongyechengfen，qielingmindujiaogao，fanyingxunsu,能在線連續指示,也可組成調節係統。工業上常用的紅外線氣體分析儀的檢測部分由兩個並列的結構相同的光學係統組成。
　　一yi個ge是shi測ce量liang室shi，一yi個ge是shi參can比bi室shi。兩liang室shi通tong過guo切qie光guang板ban以yi一yi定ding周zhou期qi同tong時shi或huo交jiao替ti開kai閉bi光guang路lu。在zai測ce量liang室shi中zhong導dao入ru被bei測ce氣qi體ti後hou，具ju有you被bei測ce氣qi體ti特te有you波bo長chang的de光guang被bei吸xi收shou
，從cong而er使shi透tou過guo測ce量liang室shi這zhe一yi光guang路lu而er進jin入ru紅hong外wai線xian接jie收shou氣qi室shi的de光guang通tong量liang減jian少shao。氣qi體ti濃nong度du越yue高gao，進jin入ru到dao紅hong外wai線xian接jie收shou氣qi室shi的de光guang通tong量liang就jiu越yue少shao；ertouguocanbishideguangtongliangshiyidingde，jinrudaohongwaixianjieshouqishideguangtongliangyeyiding。yinci，beiceqitinongduyuegao，touguoceliangshihecanbishideguangtongliangchazhijiuyueda。zhegeguangtongliangchazhishiyiyidingzhouqizhendongdezhenfutoushedaohongwaixianjieshouqishide。jieshouqishiyongjiweimihoudejinshubomofengeweiliangbanbu，shineifengyounongdujiaodadebeicezufenqiti，zaixishoubochangfanweineinengjiangsherudehongwaixianquanbuxishou，congershimaidongdeguangtongliangbianweiwendudezhouqibianhua，zaikegenjuqitaifangchengshiwendudebianhuazhuanhuanweiyalidebianhua，ranhouyongdianrongshichuanganqilaijiance
，jingguofangdachulihouzhishichubeiceqitinongdu。chuyongdianrongshichuanganqiwai，yekeyongzhijiejiancehongwaixiandeliangzishihongwaixianchuanganqi
，bingcaiyonghongwaiganshelvguangpianjinxingbochangxuanzehepeiyiketiaojiguangqizuoguangyuan
，xingchengyizhongzhanxindequangutishihongwaiqitifenxiyi。zhezhongfenxiyizhiyongyigeguangyuan、一個測量室、一(yi)個(ge)紅(hong)外(wai)線(xian)傳(chuan)感(gan)器(qi)就(jiu)能(neng)完(wan)成(cheng)氣(qi)體(ti)濃(nong)度(du)的(de)測(ce)量(liang)。此(ci)外(wai)，若(ruo)采(cai)用(yong)裝(zhuang)有(you)多(duo)個(ge)不(bu)同(tong)波(bo)長(chang)的(de)濾(lv)光(guang)盤(pan)
，則(ze)能(neng)同(tong)時(shi)分(fen)別(bie)測(ce)定(ding)多(duo)組(zu)分(fen)氣(qi)體(ti)中(zhong)的(de)各(ge)種(zhong)氣(qi)體(ti)的(de)濃(nong)度(du)。
　　與紅外線分析儀原理相似的還有紫外線分析儀、光電比色分析儀等，在工業上也用得較多。