一、ph計是什么意思
ph計是測量pH值的儀(yi)器。
ph計是(shi)專(zhuan)為使(shi)用離子選擇(ze)電(dian)(dian)(dian)極(ji)而設計(ji)的(de)一種精密(mi)的(de)電(dian)(dian)(dian)子毫伏(fu)(fu)計(ji)。由于(yu)(yu)pH指(zhi)示(shi)電(dian)(dian)(dian)極(ji)的(de)電(dian)(dian)(dian)位隨溶(rong)液(ye)(ye)pH值(zhi)(zhi)的(de)變化(hua)而變化(hua),所以當(dang)(dang)pH指(zhi)示(shi)電(dian)(dian)(dian)極(ji)(如(ru)pH玻璃電(dian)(dian)(dian)極(ji))和參(can)比電(dian)(dian)(dian)極(ji)(如(ru)飽和甘汞電(dian)(dian)(dian)極(ji))浸在(zai)(zai)溶(rong)液(ye)(ye)中(zhong)構成(cheng)測(ce)(ce)量電(dian)(dian)(dian)池時,所產生的(de)電(dian)(dian)(dian)動(dong)勢(shi)與溶(rong)液(ye)(ye)的(de)pH值(zhi)(zhi)有關。pH計(ji)將電(dian)(dian)(dian)動(dong)勢(shi)輸出轉換(huan)成(cheng)pH讀(du)(du)數(shu),每(mei)一pH間隔相當(dang)(dang)于(yu)(yu)2.303RT/F伏(fu)(fu),此值(zhi)(zhi)隨測(ce)(ce)量電(dian)(dian)(dian)池中(zhong)溶(rong)液(ye)(ye)的(de)溫(wen)度不(bu)同而變動(dong),所以pH計(ji)上(shang)都裝有溫(wen)度補償旋鈕,調(diao)節(jie)它可使(shi)每(mei)一pH間隔的(de)電(dian)(dian)(dian)動(dong)勢(shi)改變值(zhi)(zhi)正好(hao)相當(dang)(dang)于(yu)(yu)測(ce)(ce)量溫(wen)度應有的(de)變動(dong)值(zhi)(zhi)。pH計(ji)上(shang)還裝有定位調(diao)節(jie)器(qi),其作用是(shi)在(zai)(zai)電(dian)(dian)(dian)池電(dian)(dian)(dian)動(dong)勢(shi)上(shang)加一個適當(dang)(dang)電(dian)(dian)(dian)壓,使(shi)pH計(ji)讀(du)(du)數(shu)與標(biao)準(zhun)pH值(zhi)(zhi)一致。這樣,溶(rong)液(ye)(ye)的(de)pH值(zhi)(zhi)直接在(zai)(zai)儀表(biao)上(shang)顯示(shi)出來。pH計(ji)的(de)一般測(ce)(ce)量范圍(wei)是(shi)pH0~14,并(bing)備有±mV擋以擴展使(shi)用范圍(wei)。
二、ph計有哪些種類
現在(zai)市(shi)面上流(liu)通的酸(suan)(suan)度計主要為實驗室酸(suan)(suan)度計、工(gong)業(ye)pH計、便攜式pH計和筆式酸(suan)(suan)度計四大類。
1、實驗室pH計,一般為(wei)臺式儀(yi)器(qi),具(ju)有(you)精度高(gao)、重復(fu)性(xing)好、響應快(kuai)、功能全、操作簡單(dan)等特點。如果為(wei)智(zhi)能化儀(yi)器(qi),一般還(huan)具(ju)有(you)打印輸出、數據處理等功能。
2、工業pH計,主(zhu)要(yao)(yao)用于(yu)工業流(liu)程(cheng)的(de)連(lian)續測量,要(yao)(yao)求電極(ji)的(de)長期穩定(ding)性(xing)(xing)好,儀表不僅要(yao)(yao)有測量顯示功(gong)(gong)能,還要(yao)(yao)有報警(jing)和控制功(gong)(gong)能,以及(ji)方(fang)便(bian)安裝、清洗、抗干(gan)擾(rao)性(xing)(xing)能好等優勢。
3、便(bian)(bian)攜式pH計,主要(yao)用于現場測試和野外(wai)(wai)測量,要(yao)求附件配置齊全、方便(bian)(bian)攜帶,一般(ban)電源內置,方便(bian)(bian)移動(dong)測量。儀(yi)器的(de)顯示要(yao)滿足戶外(wai)(wai)不(bu)同光線條件下的(de)讀數。
4、筆(bi)式酸度計,筆式酸度(du)計(ji)是(shi)方便用戶攜帶,在(zai)現場或野外(wai)操作(zuo)而(er)設計(ji)的。可同時顯示PH值(zhi)和溫(wen)度(du)值(zhi),該儀器(qi)適用于自(zi)來(lai)水(shui)水(shui)源的監測,水(shui)族、水(shui)產、養殖、環(huan)保、印(yin)染(ran)、電鍍、飲(yin)料(liao)行(xing)業及科研單位等對(dui)水(shui)質(zhi)、PH值(zhi)的測定。