溶(rong)氧儀是(shi)測(ce)量溶(rong)解(jie)在水(shui)溶(rong)液內(nei)的氧氣的含(han)量。氧氣通過周(zhou)圍的空氣(qi)、空氣(qi)流動(dong)和光合作(zuo)用溶(rong)解(jie)於(yu)水(shui)中(zhong)。
通過呼(hu)吸和分解(jie)作(zuo)用(yong),溶(rong)解(jie)氧會(hui)在水(shui)中(zhong)消(xiao)耗(hao),主(zhu)要依靠空氣(qi)和光合作(zuo)用進(jin)行(xing)補(bu)充。水(shui)中(zhong)氧的含(han)量主要取(qu)決於(yu)溫(wen)度(du)。溫(wen)水(shui)的氧濃(nong)度(du)要(yao)低(di)於(yu)冷(leng)水(shui)。但(dan)溶(rong)氧含(han)量過高對(dui)動(dong)植物會(hui)有害。
溶(rong)氧電極(ji)可以(yi)用來(lai)測(ce)量現(xian)場或(huo)實(shi)驗室(shi)內被(bei)測(ce)樣(yang)品(pin)水(shui)溶(rong)液內(nei)的溶(rong)氧含(han)量。由於溶(rong)解(jie)氧是水(shui)的質(zhi)量的主(zhu)要指(zhi)標(biao)之(zhi)壹,因此(ci)溶(rong)氧電極(ji)可廣泛(fan)用於各種場合下(xia)的溶(rong)氧含(han)量的測(ce)量,尤其(qi)是養殖(zhi)水(shui)、光合作(zuo)用和呼(hu)吸作(zuo)用(yong)及(ji)現(xian)場測(ce)量。在對(dui)溪(xi)水(shui)和湖水(shui)支(zhi)持生物存(cun)活的能力進(jin)行(xing)評(ping)估時,要進(jin)行(xing)生化(hua)需(xu)氧量測(ce)試(shi)(BOD)在消(xiao)耗(hao)氧氣的含(han)有有機物(wu)的樣(yang)品(pin)水(shui)溶(rong)液變腐時對其(qi)進(jin)行(xing)測(ce)量並確(que)定溶(rong)氧濃(nong)度(du)和樣(yang)品(pin)水(shui)溶(rong)液溫(wen)度(du)之(zhi)間(jian)的關(guan)系(xi)。
中(zhong)文(wen)在線(xian)溶(rong)氧儀是(shi)高智(zhi)能化(hua)在線(xian)連續(xu)監(jian)測(ce)儀(yi)。可以(yi)配極(ji)譜(pu)式(shi)電極(ji),自(zi)動(dong)實(shi)現(xian)從ppb級到(dao)ppm級的寬範圍測(ce)量,是檢(jian)測(ce)鍋爐給(gei)水(shui)、凝(ning)結(jie)水(shui)、環(huan)保汙水(shui)等行(xing)業的液體(ti)中(zhong)氧含(han)量測(ce)量的儀(yi)器。溶(rong)氧電極(ji)用(yong)壹薄(bo)膜(mo)將鉑(bo)陰極(ji),銀(yin)陽極(ji),以(yi)及電(dian)解(jie)質(zhi)與(yu)外(wai)界(jie)隔(ge)開(kai),壹般(ban)情(qing)況下(xia)陰極(ji)幾乎(hu)是和這(zhe)層(ceng)膜(mo)直(zhi)接(jie)接(jie)觸的。氧以(yi)和其(qi)分壓成(cheng)正(zheng)比(bi)的比(bi)率透過膜(mo)擴(kuo)散,氧分壓越(yue)大(da),透過膜(mo)的氧就越(yue)多(duo)。當溶(rong)解(jie)氧不斷(duan)地(di)透過膜(mo)滲(shen)入(ru)腔(qiang)體(ti),在陰極(ji)上(shang)還(hai)原(yuan)而(er)產(chan)生電流(liu),此(ci)電流在儀(yi)表(biao)上(shang)顯(xian)示出來(lai)。由於(yu)此(ci)電(dian)流和溶(rong)氧濃(nong)度(du)直(zhi)接(jie)成(cheng)正(zheng)比(bi),因(yin)此(ci)校正(zheng)儀(yi)表(biao)只(zhi)需(xu)將測(ce)得(de)的電(dian)流轉(zhuan)換(huan)為(wei)濃(nong)度(du)單(dan)位(wei)即(ji)可。
溶(rong)氧濃(nong)度(du)通常用(yong)mg/L(每(mei)升(sheng)水(shui)的溶(rong)氧量)或ppm(百萬分之(zhi)幾)。有些儀(yi)表將計算(suan)出的氧含(han)量和觀(guan)察(cha)到(dao)的濃(nong)度(du)進(jin)行(xing)比(bi)較(jiao)得出飽和度(du)百(bai)分比(bi)(O2%sat.)
確(que)定溶(rong)氧儀溶(rong)氧有兩種方(fang)式(shi),極(ji)譜(pu)式(shi)和原(yuan)電(dian)池(chi)式(shi)。極(ji)譜(pu)式(shi)電極(ji)需(xu)儀表(biao)輸入(ru)壹(yi)電(dian)壓對電(dian)極(ji)進(jin)行(xing)極(ji)化(hua)。由(you)於(yu)外(wai)加(jia)電(dian)壓可能要15分鐘(zhong)才能穩定,因此極(ji)譜(pu)式(shi)電極(ji)使用前(qian)通常要(yao)進(jin)行(xing)預(yu)熱(re)確(que)保電(dian)極(ji)能妥當極(ji)化(hua)。原(yuan)電(dian)池(chi)式(shi)的兩(liang)個極(ji)由(you)兩種不同(tong)的能自(zi)發極(ji)化(hua)產(chan)生電壓的金(jin)屬構(gou)成(cheng)。由(you)於(yu)原(yuan)電(dian)池(chi)式(shi)的電(dian)壓是自(zi)發產(chan)生而不(bu)是(shi)外(wai)界(jie)提供(gong)的,因(yin)此原(yuan)電(dian)池(chi)式(shi)電極(ji)使用時無(wu)需(xu)極(ji)譜(pu)式(shi)電極(ji)極(ji)化(hua)所需(xu)的“預(yu)熱(re)”。