電導率分析儀采用嵌入式系統設計,集信號采集、數據處理、顯示功能與一體,智能化程度高,測量準確,操作方便;用于測量水溶液導電能力的強弱,從而間接判斷溶液中離子含量的多少或水質的好壞等,廣泛應用于電力、石油化工、食品品飲料、造紙等行業,也可以用于高等院校、科研機構等進行教學或科學研究。
電導(dao)率分析儀的工作原理:
在電(dian)(dian)(dian)(dian)解質的(de)(de)溶液(ye)中(zhong),帶電(dian)(dian)(dian)(dian)的(de)(de)離子(zi)(zi)在電(dian)(dian)(dian)(dian)場的(de)(de)影(ying)響下,產生移(yi)動而(er)傳(chuan)遞電(dian)(dian)(dian)(dian)子(zi)(zi),因(yin)此,具有導(dao)電(dian)(dian)(dian)(dian)作用。其導(dao)電(dian)(dian)(dian)(dian)能力的(de)(de)強弱稱為電(dian)(dian)(dian)(dian)導(dao)度(du)S。因(yin)為電(dian)(dian)(dian)(dian)導(dao)是電(dian)(dian)(dian)(dian)阻(zu)的(de)(de)倒數,因(yin)此,測(ce)量電(dian)(dian)(dian)(dian)導(dao)大小(xiao)的(de)(de)方法,可用兩個(ge)電(dian)(dian)(dian)(dian)極(ji)(ji)插入溶液(ye)中(zhong),以測(ce)出兩個(ge)極(ji)(ji)間的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)R。據歐姆定律,溫度(du)一定時(shi),這個(ge)電(dian)(dian)(dian)(dian)阻(zu)與(yu)電(dian)(dian)(dian)(dian)極(ji)(ji)的(de)(de)間距(ju)L(cm)成正比(bi),與(yu)電(dian)(dian)(dian)(dian)極(ji)(ji)的(de)(de)截(jie)面積(ji)A(cm)反比(bi)。
電(dian)(dian)導(dao)(dao)率(lv)是以(yi)數字表示溶液傳導(dao)(dao)電(dian)(dian)流的能(neng)力。水(shui)的電(dian)(dian)導(dao)(dao)率(lv)與(yu)其(qi)所含無(wu)機酸、堿、鹽的量有一定(ding)的關系,當它們的濃度較低時(shi),電(dian)(dian)導(dao)(dao)率(lv)隨著濃度的增(zeng)大而增(zeng)加,因(yin)此(ci),該(gai)指(zhi)標常(chang)用于(yu)推測水(shui)中離子的總濃度或含鹽量。
電導(G)是電阻(R)的(de)倒數。因此(ci)當兩個電極(ji)插入溶液中(zhong),可以測出兩電極(ji)間的(de)電阻R。根據歐姆(mu)定律,溫度一定時,這個電阻值與(yu)電極(ji)間距L(cm)正比(bi),與(yu)電極(ji)的(de)截面積A(cm2)反(fan)比(bi),即:R =ρ×(L/A)
其中ρ為(wei)電阻率,是長(chang)1cm,截面積(ji)為(wei)1cm2導體的(de)電阻,其大(da)小決定于物質的(de)本性。
據上式,導(dao)體的電導(dao)(G)可表示成下式:G =1/R=(1/ρ)×(A/L)=K×(1/J)
其中,K=1/ρ稱為電(dian)導率,J =L/A稱為電(dian)極常數
電(dian)(dian)(dian)解質溶(rong)液電(dian)(dian)(dian)導率指相距(ju)1cm的(de)兩平行電(dian)(dian)(dian)極間充(chong)以1cm3溶(rong)液時(shi)所具有的(de)電(dian)(dian)(dian)導。由上式可見,當(dang)已知電(dian)(dian)(dian)極常數(shu)(J),并(bing)測出(chu)溶(rong)液電(dian)(dian)(dian)阻(R)或電(dian)(dian)(dian)導(G)時(shi),即可求出(chu)電(dian)(dian)(dian)。