測量柴油凝點時觀察試樣的流動(dong)性

試樣(yang)(yang)從高于預期傾點(dian)(dian)9C(估算為(wei)3C倍數(shu))開始觀(guan)察試樣(yang)(yang)的流(liu)(liu)動(dong)(dong)性。每當溫(wen)(wen)(wen)(wen)度(du)計讀(du)數(shu)降(jiang)低(di)3C°時(shi)，要小心(xin)地把試管(guan)(guan)從冷浴(yu)(yu)中取(qu)出，將試管(guan)(guan)充(chong)分(fen)傾斜(xie)以(yi)確定試樣(yang)(yang)是否流(liu)(liu)動(dong)(dong)。取(qu)出試管(guan)(guan)、觀(guan)察試樣(yang)(yang)流(liu)(liu)動(dong)(dong)性和返回(hui)到浴(yu)(yu)中的全部操作要求不超過3S。如果(guo)溫(wen)(wen)(wen)(wen)度(du)已降(jiang)到9C°，試樣(yang)(yang)仍流(liu)(liu)動(dong)(dong)，則將試管(guan)(guan)移到溫(wen)(wen)(wen)(wen)度(du)保持(chi)在-18~-15C°的冷浴(yu)(yu)套管(guan)(guan)中;如果(guo)溫(wen)(wen)(wen)(wen)度(du)已降(jiang)到-6C°，試樣(yang)(yang)仍流(liu)(liu)動(dong)(dong)，則將試管(guan)(guan)移到溫(wen)(wen)(wen)(wen)度(du)保持(chi)在-35~ -32C的冷浴(yu)(yu)套管(guan)(guan)中。測定極低(di)的傾點(dian)(dian)時(shi)，需(xu)要多個不同溫(wen)(wen)(wen)(wen)度(du)的冷浴(yu)(yu)，每個冷浴(yu)(yu)間的溫(wen)(wen)(wen)(wen)差為(wei)17C°，如-52~-49C°、 -69~-66C*和-86~-83C°等。當傾斜(xie)試管(guan)(guan)，發現試樣(yang)(yang)不流(liu)(liu)動(dong)(dong)時(shi)，就立即(ji)將試管(guan)(guan)放在水(shui)平位置上仔細觀(guan)察試樣(yang)(yang)的表(biao)面，如果(guo)在5s內還有流(liu)(liu)動(dong)(dong)，則立即(ji)將試管(guan)(guan)放回(hui)冷浴(yu)(yu)，待再降(jiang)低(di)3C°時(shi)，重復進行流(liu)(liu)動(dong)(dong)試驗。