被檢(jian)測氣體(ti)(ti)的濃度取決于氣體(ti)(ti)檢(jian)測變送器(qi)(qi)，傳感器(qi)(qi)是其(qi)核心部分。根據檢(jian)測原理的不(bu)同(tong)，主(zhu)要分為金屬氧化物半導體(ti)(ti)傳感器(qi)(qi)、催(cui)化燃燒傳感器(qi)(qi)、恒電位電解氣體(ti)(ti)傳感器(qi)(qi)、瓦(wa)尼電池氧傳感器(qi)(qi)、紅外傳感器(qi)(qi)、PID光電離傳感器(qi)(qi)等。下面簡要概(gai)述其(qi)原理和特點各種傳感器(qi)(qi)。

一個。金(jin)屬氧化物半導體(ti)傳感器

金屬(shu)氧化物半導體(ti)傳(chuan)感(gan)器(qi)利用(yong)被(bei)測(ce)氣體(ti)的吸附(fu)作用(yong)來改變半導體(ti)的電導率，并(bing)通過電流變化的比較來激活報警電路。由于(yu)半導體(ti)傳(chuan)感(gan)器(qi)在(zai)測(ce)量過程中受環(huan)境影(ying)響(xiang)較大，輸(shu)出線(xian)形不穩定。金屬(shu)氧化物半導體(ti)傳(chuan)感(gan)器(qi)響(xiang)應靈敏，被(bei)廣泛(fan)應用(yong)于(yu)氣體(ti)微泄漏測(ce)量領域。

b.催化燃燒傳感器

催化(hua)(hua)燃(ran)燒(shao)傳(chuan)感(gan)器(qi)(qi)的(de)(de)原理是(shi)檢測可(ke)燃(ran)氣(qi)體(ti)應(ying)(ying)用*泛的(de)(de)原理之一(yi)。具有輸(shu)出信號線形(xing)好、指標可(ke)靠、價格(ge)低廉(lian)、與其他不燃(ran)氣(qi)體(ti)無交(jiao)叉干擾(rao)等特點。催化(hua)(hua)燃(ran)燒(shao)傳(chuan)感(gan)器(qi)(qi)采用惠斯(si)通電(dian)(dian)(dian)橋原理，感(gan)應(ying)(ying)電(dian)(dian)(dian)阻與環境中的(de)(de)可(ke)燃(ran)氣(qi)體(ti)無火焰(yan)燃(ran)燒(shao)，使(shi)溫度改變感(gan)應(ying)(ying)電(dian)(dian)(dian)阻的(de)(de)阻值，打破(po)電(dian)(dian)(dian)橋的(de)(de)平衡，使(shi)其輸(shu)出穩定的(de)(de)電(dian)(dian)(dian)流信號，再經過(guo)后期(qi)電(dian)(dian)(dian)路的(de)(de)放大(da)、穩壓、處理，終顯示(shi)出可(ke)靠的(de)(de)數值。

c。恒電(dian)位電(dian)解氣體傳(chuan)感(gan)器

恒電(dian)(dian)(dian)(dian)(dian)位(wei)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)傳感(gan)器(qi)(qi)是目前(qian)藥(yao)物(wu)檢測(ce)領域應用*泛的技(ji)(ji)術。在(zai)這方面，外技(ji)(ji)術較為(wei)，所以(yi)這些傳感(gan)器(qi)(qi)大多依賴進口。恒電(dian)(dian)(dian)(dian)(dian)位(wei)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)氣體傳感(gan)器(qi)(qi)的結構：在(zai)塑料(liao)制(zhi)成的圓柱形(xing)電(dian)(dian)(dian)(dian)(dian)池內(nei)，安裝工(gong)作電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)、對電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)和參比電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)之(zhi)間(jian)填充電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)液(ye)，頂部封裝多孔(kong)四氟乙烯(xi)隔膜前(qian)置放大器(qi)(qi)和傳感(gan)器(qi)(qi)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)之(zhi)間(jian)的連接在(zai)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)之(zhi)間(jian)施加一定(ding)的電(dian)(dian)(dian)(dian)(dian)位(wei)，使傳感(gan)器(qi)(qi)工(gong)作。氣體在(zai)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)液(ye)中(zhong)與(yu)工(gong)作電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)發(fa)生反應，在(zai)對電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)發(fa)生還原或氧化反應。電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)的平衡電(dian)(dian)(dian)(dian)(dian)位(wei)發(fa)生變化，變化值(zhi)與(yu)氣體濃度(du)成正(zheng)比。

d。伽(jia)伐(fa)尼電池(chi)氧傳感器

隔膜伽伐尼電(dian)(dian)池式(shi)氧傳(chuan)感(gan)器的(de)結構(gou)：在塑(su)料容器的(de)一(yi)側安裝一(yi)層10~30μm厚的(de)透氧性良好的(de)聚(ju)四氟乙烯透氣膜，內(nei)部緊貼(tie)貴金屬(shu)(shu)（鉑）的(de)容器。 、金、銀等(deng)(deng)）陰極(ji)(ji)(ji)電(dian)(dian)極(ji)(ji)(ji)，陽(yang)(yang)極(ji)(ji)(ji)（與鉛、鎘等(deng)(deng)電(dian)(dian)離(li)傾向大(da)(da)的(de)金屬(shu)(shu)）形成于容器另一(yi)側的(de)內(nei)側或容器的(de)空部。與氫氧化(hua)鉀。當氧氣通過電(dian)(dian)解質時(shi)，陰極(ji)(ji)(ji)和陽(yang)(yang)極(ji)(ji)(ji)會(hui)發(fa)生氧化(hua)還(huan)原(yuan)反(fan)(fan)應，使陽(yang)(yang)極(ji)(ji)(ji)金屬(shu)(shu)離(li)子(zi)化(hua)并釋放電(dian)(dian)子(zi)。電(dian)(dian)流(liu)的(de)大(da)(da)小與氧氣的(de)量成正比。由于整個(ge)反(fan)(fan)應過程中都會(hui)消耗陽(yang)(yang)極(ji)(ji)(ji)金屬(shu)(shu)，因此需要(yao)定期更換傳(chuan)感(gan)器。目(mu)前(qian)內(nei)技(ji)術已經(jing)越來(lai)越成熟，*可以(yi)產化(hua)這(zhe)樣的(de)傳(chuan)感(gan)器。

e。紅外線感應器

紅外傳(chuan)感器利用各種元素(su)對某(mou)一波長(chang)的吸收原理。抗毒性(xing)好，反應靈敏(min)，對大多數碳氫化合物都有反應。但(dan)結(jie)構復雜，成本高。

f。 PID光(guang)電離氣體(ti)傳(chuan)感器

PID由紫外光源(yuan)、離(li)子(zi)室等主要部分(fen)組成(cheng)。離(li)子(zi)室內有正負電(dian)極，形成(cheng)電(dian)場。在紫外燈的(de)照(zhao)射(she)下，待測氣(qi)體(ti)被電(dian)離(li)，產生正負離(li)子(zi)，電(dian)極間形成(cheng)電(dian)流。放大后的(de)輸出信號。 PID具有靈(ling)敏度高、無中毒問(wen)題、安全可靠等優點。