測量煙氣(qi)中含氧(yang)量的儀表稱為(wei)氧(yang)分析儀(氧量計)。常用的氧分析儀主要有熱磁式和氧化鋯(gao)式兩種。

熱磁式

其原理(li)是(shi)利(li)用煙氣(qi)組分中氧氣(qi)的(de)磁化(hua)率特別高這一物(wu)理(li)特性來測定(ding)煙氣(qi)中含氧量。氧氣(qi)為順磁性氣(qi)體(氣(qi)(qi)體(ti)能被磁(ci)(ci)(ci)(ci)場(chang)所吸引的稱(cheng)為(wei)順磁(ci)(ci)(ci)(ci)性(xing)氣(qi)(qi)體(ti))，在(zai)不(bu)(bu)均勻磁(ci)(ci)(ci)(ci)場(chang)中受到(dao)吸引而(er)流向(xiang)磁(ci)(ci)(ci)(ci)場(chang)較強處(chu)(chu)。在(zai)該處(chu)(chu)設有加(jia)熱(re)絲(si)，使此(ci)處(chu)(chu)氧(yang)的溫度(du)(du)升高而(er)磁(ci)(ci)(ci)(ci)化率下(xia)(xia)降，因(yin)而(er)磁(ci)(ci)(ci)(ci)場(chang)吸引力(li)減小(xiao)，受后(hou)面磁(ci)(ci)(ci)(ci)化率較高的未被加(jia)熱(re)的氧(yang)氣(qi)(qi)分(fen)子推擠而(er)排(pai)出(chu)磁(ci)(ci)(ci)(ci)場(chang)，由(you)(you)此(ci)造成"熱(re)磁(ci)(ci)(ci)(ci)對流"或"磁(ci)(ci)(ci)(ci)風"現(xian)象(xiang)。在(zai)一定的氣(qi)(qi)樣(yang)壓(ya)力(li)、溫度(du)(du)和(he)流量(liang)下(xia)(xia)，通(tong)過(guo)測量(liang)磁(ci)(ci)(ci)(ci)風大小(xiao)就可測得氣(qi)(qi)樣(yang)中氧(yang)氣(qi)(qi)含量(liang)。由(you)(you)于(yu)熱(re)敏元(yuan)件(鉑絲(si))既作為(wei)不(bu)(bu)平衡電(dian)(dian)橋(qiao)的兩個橋(qiao)臂(bei)電(dian)(dian)阻，又作為(wei)加(jia)熱(re)電(dian)(dian)阻絲(si)，在(zai)磁(ci)(ci)(ci)(ci)風的作用下(xia)(xia)出(chu)現(xian)溫度(du)(du)梯度(du)(du)，即進(jin)氣(qi)(qi)側橋(qiao)臂(bei)的溫度(du)(du)低于(yu)出(chu)氣(qi)(qi)側橋(qiao)臂(bei)的溫度(du)(du)。不(bu)(bu)平衡電(dian)(dian)橋(qiao)將隨著(zhu)氣(qi)(qi)樣(yang)中氧(yang)氣(qi)(qi)含量(liang)的不(bu)(bu)同，輸(shu)出(chu)相應的電(dian)(dian)壓(ya)值(zhi)。

熱磁式氧(yang)分析(xi)儀雖然具有結構簡單、便于(yu)制造和(he)調整等(deng)(deng)優點(dian)，但由(you)于(yu)其(qi)反(fan)應速度慢、測量(liang)誤差大、容易發生測量(liang)環(huan)室堵塞和(he)熱敏元件腐蝕嚴重等(deng)(deng)缺點(dian)，已逐漸被氧(yang)化鋯氧(yang)分析(xi)儀所取代。

傳感器式

氧化(hua)鋯(ZrO2)是一(yi)(yi)種陶瓷(ci)，一(yi)(yi)種具有(you)離(li)子(zi)(zi)導電(dian)(dian)(dian)(dian)(dian)(dian)(dian)性質的(de)(de)(de)(de)(de)(de)固(gu)體(ti)(ti)。在常(chang)溫下為(wei)(wei)單斜(xie)晶體(ti)(ti)，當(dang)溫度(du)(du)升(sheng)高到1150℃時(shi)(shi)(shi)，晶型轉變(bian)為(wei)(wei)立方晶體(ti)(ti)，同(tong)(tong)時(shi)(shi)(shi)約有(you)7%的(de)(de)(de)(de)(de)(de)體(ti)(ti)積收縮;當(dang)溫度(du)(du)降低時(shi)(shi)(shi)，又變(bian)為(wei)(wei)單斜(xie)晶體(ti)(ti)。若反(fan)復加熱與冷(leng)卻，ZrO2就會破裂。因(yin)此，純凈的(de)(de)(de)(de)(de)(de)ZrO2不(bu)能用(yong)作(zuo)測量(liang)元件。如(ru)果在ZrO2中(zhong)加入一(yi)(yi)定量(liang)的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)化鈣(CaO)或氧(yang)(yang)(yang)(yang)(yang)化釔(Y2O3)作(zuo)穩定劑(ji)，再(zai)經過(guo)高溫焙燒(shao)，則變(bian)為(wei)(wei)穩定的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)化鋯材(cai)料，這時(shi)(shi)(shi)，四價的(de)(de)(de)(de)(de)(de)鋯被二價的(de)(de)(de)(de)(de)(de)鈣或三價的(de)(de)(de)(de)(de)(de)釔置換，同(tong)(tong)時(shi)(shi)(shi)產(chan)生(sheng)氧(yang)(yang)(yang)(yang)(yang)離(li)子(zi)(zi)空(kong)(kong)穴，所以ZrO2屬于陰(yin)離(li)子(zi)(zi)固(gu)體(ti)(ti)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)解質。ZrO2主要通(tong)過(guo)空(kong)(kong)穴的(de)(de)(de)(de)(de)(de)運動而導電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，當(dang)溫度(du)(du)達到600℃以上時(shi)(shi)(shi)，ZrO2就變(bian)為(wei)(wei)良好的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)離(li)子(zi)(zi)導體(ti)(ti)。 在氧(yang)(yang)(yang)(yang)(yang)化鋯電(dian)(dian)(dian)(dian)(dian)(dian)(dian)解質的(de)(de)(de)(de)(de)(de)兩面各(ge)燒(shao)結一(yi)(yi)個鉑(bo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)，當(dang)氧(yang)(yang)(yang)(yang)(yang)化鋯兩側(ce)(ce)的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)分壓(ya)不(bu)同(tong)(tong)時(shi)(shi)(shi)，氧(yang)(yang)(yang)(yang)(yang)分壓(ya)高的(de)(de)(de)(de)(de)(de)一(yi)(yi)側(ce)(ce)的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)以離(li)子(zi)(zi)形式向(xiang)氧(yang)(yang)(yang)(yang)(yang)分壓(ya)低的(de)(de)(de)(de)(de)(de)一(yi)(yi)側(ce)(ce)遷移，結果使氧(yang)(yang)(yang)(yang)(yang)分壓(ya)高的(de)(de)(de)(de)(de)(de)一(yi)(yi)側(ce)(ce)鉑(bo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)失去電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)顯(xian)正(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，而氧(yang)(yang)(yang)(yang)(yang)分壓(ya)低的(de)(de)(de)(de)(de)(de)一(yi)(yi)側(ce)(ce)鉑(bo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)得到電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)顯(xian)負電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，因(yin)而在兩鉑(bo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)之間(jian)產(chan)生(sheng)氧(yang)(yang)(yang)(yang)(yang)濃(nong)(nong)差(cha)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢。此電(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢在溫度(du)(du)一(yi)(yi)定時(shi)(shi)(shi)只與兩側(ce)(ce)氣(qi)(qi)體(ti)(ti)中(zhong)氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)含(han)量(liang)的(de)(de)(de)(de)(de)(de)差(cha)(氧(yang)(yang)(yang)(yang)(yang)濃(nong)(nong)差(cha))有(you)關。若一(yi)(yi)側(ce)(ce)氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)含(han)量(liang)已知(zhi)(如(ru)空(kong)(kong)氣(qi)(qi)中(zhong)氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)含(han)量(liang)為(wei)(wei)常(chang)數)，則另一(yi)(yi)側(ce)(ce)氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)含(han)量(liang)(如(ru)煙氣(qi)(qi)中(zhong)氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)含(han)量(liang))就可用(yong)氧(yang)(yang)(yang)(yang)(yang)濃(nong)(nong)差(cha)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢表(biao)示(shi)，測出(chu)氧(yang)(yang)(yang)(yang)(yang)濃(nong)(nong)差(cha)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢，便可知(zhi)道煙氣(qi)(qi)中(zhong)氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)含(han)量(liang)。

氧化(hua)鋯(gao)氧分析儀(yi)具有(you)結構和(he)采樣預(yu)處理(li)系統(tong)較簡單、靈敏度和(he)分辨率高、測量范(fan)圍寬、響應速度較快等優(you)點。

相關氧化鋯，氧化鋯氧量分(fen)析(xi)儀, 電磁(ci)流量計等產品(pin)的技術(shu)說明，請見智瑞科技官(guan)方網站。

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