- 熱電偶和熱電阻區別
熱電偶與熱電阻均屬于溫度測(ce)量(liang)中的(de)接觸式測(ce)溫,盡(jin)管其(qi)作用相(xiang)同都是測(ce)量(liang)物體的(de)溫度,但是他 們(men)的(de)原(yuan)理與特點卻(que)不盡(jin)相(xiang)同.
首(shou)先,介紹一下熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou),熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)是(shi)(shi)(shi)溫(wen)度測量中(zhong)(zhong)應(ying)用zui廣泛的(de)(de)(de)(de)(de)(de)(de)(de)溫(wen)度器(qi)件,他(ta)的(de)(de)(de)(de)(de)(de)(de)(de)主要特點就是(shi)(shi)(shi)測吻(wen)范圍寬(kuan),性(xing)能(neng)比(bi)較(jiao)穩(wen)定(ding),同(tong)(tong)(tong)(tong)時(shi)結(jie)構簡單,動態響應(ying)好,更能(neng)夠遠傳4-20mA電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)信號,便于(yu)自動控制和(he)(he)(he)集(ji)中(zhong)(zhong)控制。熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)的(de)(de)(de)(de)(de)(de)(de)(de)測溫(wen)原理是(shi)(shi)(shi)基于(yu)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)效(xiao)應(ying)。將(jiang)兩(liang)(liang)種不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)(de)導體(ti)(ti)或半導體(ti)(ti)連接成(cheng)閉合(he)(he)回(hui)(hui)路(lu)(lu),當兩(liang)(liang)個接點處的(de)(de)(de)(de)(de)(de)(de)(de)溫(wen)度不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)時(shi),回(hui)(hui)路(lu)(lu)中(zhong)(zhong)將(jiang)產(chan)生(sheng)(sheng)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi),這(zhe)種現象(xiang)稱(cheng)(cheng)為(wei)(wei)(wei)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)效(xiao)應(ying),又(you)(you)稱(cheng)(cheng)為(wei)(wei)(wei)塞貝克效(xiao)應(ying)。閉合(he)(he)回(hui)(hui)路(lu)(lu)中(zhong)(zhong)產(chan)生(sheng)(sheng)的(de)(de)(de)(de)(de)(de)(de)(de)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)有兩(liang)(liang)種電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)組(zu)成(cheng);溫(wen)差電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)和(he)(he)(he)接觸電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)。溫(wen)差電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)是(shi)(shi)(shi)指同(tong)(tong)(tong)(tong)一導體(ti)(ti)的(de)(de)(de)(de)(de)(de)(de)(de)兩(liang)(liang)端(duan)因(yin)溫(wen)度不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)而(er)產(chan)生(sheng)(sheng)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi),不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)(de)導體(ti)(ti)具有不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子密度,所以(yi)他(ta)們(men)(men)產(chan)生(sheng)(sheng)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)也不(bu)(bu)(bu)相(xiang)(xiang)(xiang)同(tong)(tong)(tong)(tong),而(er)接觸電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)顧名思義就是(shi)(shi)(shi)指兩(liang)(liang)種不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)(de)導體(ti)(ti)相(xiang)(xiang)(xiang)接觸時(shi),因(yin)為(wei)(wei)(wei)他(ta)們(men)(men)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子密度不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)所以(yi)產(chan)生(sheng)(sheng)一定(ding)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子擴散,當他(ta)們(men)(men)達(da)到(dao)一定(ding)的(de)(de)(de)(de)(de)(de)(de)(de)平衡后所形成(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi),接觸電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)的(de)(de)(de)(de)(de)(de)(de)(de)大(da)小取(qu)決(jue)于(yu)兩(liang)(liang)種不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)導體(ti)(ti)的(de)(de)(de)(de)(de)(de)(de)(de)材料性(xing)質(zhi)以(yi)及他(ta)們(men)(men)接觸點的(de)(de)(de)(de)(de)(de)(de)(de)溫(wen)度。目前(qian)國際上應(ying)用的(de)(de)(de)(de)(de)(de)(de)(de)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)具有一個標準規范,國際上規定(ding)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)分(fen)(fen)為(wei)(wei)(wei)八個不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)(de)分(fen)(fen)度,分(fen)(fen)別為(wei)(wei)(wei)B,R,S,K,N,E,J和(he)(he)(he)T,其測量溫(wen)度的(de)(de)(de)(de)(de)(de)(de)(de)zui低可(ke)測零下270攝(she)氏度,zui高可(ke)達(da)1800攝(she)氏度,其中(zhong)(zhong)B,R,S屬于(yu)鉑系列的(de)(de)(de)(de)(de)(de)(de)(de)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou),由于(yu)鉑屬于(yu)貴重金屬,所以(yi)他(ta)們(men)(men)又(you)(you)被稱(cheng)(cheng)為(wei)(wei)(wei)貴金屬熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)而(er)剩下的(de)(de)(de)(de)(de)(de)(de)(de)幾個則稱(cheng)(cheng)為(wei)(wei)(wei)廉(lian)價金屬熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)。熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)的(de)(de)(de)(de)(de)(de)(de)(de)結(jie)構有兩(liang)(liang)種,普通(tong)型(xing)(xing)和(he)(he)(he)鎧裝(zhuang)(zhuang)型(xing)(xing)。普通(tong)性(xing)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)一般(ban)由熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極,絕緣管,保護套管和(he)(he)(he)接線(xian)(xian)(xian)(xian)(xian)盒等部分(fen)(fen)組(zu)成(cheng),而(er)鎧裝(zhuang)(zhuang)型(xing)(xing)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)則是(shi)(shi)(shi)將(jiang)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)絲(si),絕緣材料和(he)(he)(he)金屬保護套管三者組(zu)合(he)(he)裝(zhuang)(zhuang)配后,經過(guo)拉伸(shen)加工而(er)成(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)一種堅實的(de)(de)(de)(de)(de)(de)(de)(de)組(zu)合(he)(he)體(ti)(ti)。但是(shi)(shi)(shi)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)信號卻需(xu)要一種特殊(shu)的(de)(de)(de)(de)(de)(de)(de)(de)導線(xian)(xian)(xian)(xian)(xian)來進行傳遞,這(zhe)種導線(xian)(xian)(xian)(xian)(xian)我們(men)(men)稱(cheng)(cheng)為(wei)(wei)(wei)補(bu)償(chang)(chang)導線(xian)(xian)(xian)(xian)(xian)。不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)(de)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)需(xu)要不(bu)(bu)(bu)同(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)(de)補(bu)償(chang)(chang)導線(xian)(xian)(xian)(xian)(xian),其主要作用就是(shi)(shi)(shi)與(yu)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)連接,使熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)的(de)(de)(de)(de)(de)(de)(de)(de)參比(bi)端(duan)遠離電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan),從而(er)使參比(bi)端(duan)溫(wen)度穩(wen)定(ding)。補(bu)償(chang)(chang)導線(xian)(xian)(xian)(xian)(xian)又(you)(you)分(fen)(fen)為(wei)(wei)(wei)補(bu)償(chang)(chang)型(xing)(xing)和(he)(he)(he)延長(chang)型(xing)(xing)兩(liang)(liang)種,延長(chang)導線(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)(de)(de)(de)化(hua)學(xue)成(cheng)分(fen)(fen)與(yu)被補(bu)償(chang)(chang)的(de)(de)(de)(de)(de)(de)(de)(de)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)相(xiang)(xiang)(xiang)同(tong)(tong)(tong)(tong),但是(shi)(shi)(shi)實際中(zhong)(zhong),延長(chang)型(xing)(xing)的(de)(de)(de)(de)(de)(de)(de)(de)導線(xian)(xian)(xian)(xian)(xian)也并不(bu)(bu)(bu)是(shi)(shi)(shi)用和(he)(he)(he)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)相(xiang)(xiang)(xiang)同(tong)(tong)(tong)(tong)材質(zhi)的(de)(de)(de)(de)(de)(de)(de)(de)金屬,一般(ban)采(cai)用和(he)(he)(he)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)具有相(xiang)(xiang)(xiang)同(tong)(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子密度的(de)(de)(de)(de)(de)(de)(de)(de)導線(xian)(xian)(xian)(xian)(xian)代替(ti)。補(bu)償(chang)(chang)導線(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)(de)(de)(de)與(yu)熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)的(de)(de)(de)(de)(de)(de)(de)(de)連線(xian)(xian)(xian)(xian)(xian)一般(ban)都是(shi)(shi)(shi)很明了,熱(re)(re)(re)(re)(re)(re)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)偶(ou)(ou)(ou)(ou)(ou)(ou)的(de)(de)(de)(de)(de)(de)(de)(de)正(zheng)極連接補(bu)償(chang)(chang)導線(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)(de)(de)(de)紅(hong)色(se)線(xian)(xian)(xian)(xian)(xian),而(er)負極則連接剩下的(de)(de)(de)(de)(de)(de)(de)(de)顏色(se)。一般(ban)的(de)(de)(de)(de)(de)(de)(de)(de)補(bu)償(chang)(chang)導線(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)(de)(de)(de)材質(zhi)大(da)部分(fen)(fen)都采(cai)用銅鎳合(he)(he)金。
其次我們介紹一(yi)下熱(re)電(dian)(dian)(dian)阻(zu),熱(re)電(dian)(dian)(dian)阻(zu)雖然(ran)在工業(ye)中應用(yong)(yong)也比(bi)較廣泛,但是(shi)由(you)于(yu)他(ta)的(de)(de)測(ce)(ce)溫范圍(wei)(wei)使(shi)他(ta)的(de)(de)應用(yong)(yong)受到(dao)了(le)一(yi)定的(de)(de)限制,熱(re)電(dian)(dian)(dian)阻(zu)的(de)(de)測(ce)(ce)溫原理(li)是(shi)基(ji)于(yu)導體或半(ban)導體的(de)(de)電(dian)(dian)(dian)阻(zu)值隨(sui)著溫度的(de)(de)變(bian)化(hua)而變(bian)化(hua)的(de)(de)特性。其優點也很多(duo),也可(ke)以(yi)遠傳電(dian)(dian)(dian)信(xin)號,靈(ling)敏度高,穩定性強,互(hu)換性以(yi)及準確(que)性都比(bi)較好,但是(shi)需(xu)要電(dian)(dian)(dian)源激勵,不能夠瞬時測(ce)(ce)量溫度的(de)(de)變(bian)化(hua)。工業(ye)用(yong)(yong)熱(re)電(dian)(dian)(dian)阻(zu)一(yi)般采用(yong)(yong)Pt100,Pt10,Cu50,Cu100,鉑熱(re)電(dian)(dian)(dian)阻(zu)的(de)(de)測(ce)(ce)溫的(de)(de)范圍(wei)(wei)一(yi)般為零下200-800攝氏(shi)(shi)度,銅熱(re)電(dian)(dian)(dian)阻(zu)為零下40到(dao)140攝氏(shi)(shi)度。熱(re)電(dian)(dian)(dian)阻(zu)和熱(re)電(dian)(dian)(dian)偶一(yi)樣的(de)(de)區分(fen)類型,但是(shi)他(ta)卻不需(xu)要補償導線,而且比(bi)熱(re)點偶便宜。
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