定襄機械密封包括壓力控制、溫度控制、流體替換(堵塞)和雜質去除系統。在定襄機械密封系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)中，上(shang)述(shu)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)并(bing)不(bu)同時包括在(zai)內。密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)的(de)選擇主(zhu)(zhu)要取決于(yu)主(zhu)(zhu)密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)件的(de)應(ying)(ying)用(yong)(yong)(yong)范圍。例如，如果主(zhu)(zhu)密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)用(yong)(yong)(yong)于(yu)高溫液體，密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)應(ying)(ying)確保(bao)降(jiang)低主(zhu)(zhu)密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)的(de)環境(jing)溫度(du)，即(ji)采用(yong)(yong)(yong)溫度(du)控(kong)制系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)。如果主(zhu)(zhu)密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)用(yong)(yong)(yong)于(yu)固體雜(za)質(zhi)含(han)量高的(de)工作介質(zhi)，密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)應(ying)(ying)確保(bao)在(zai)主(zhu)(zhu)密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)前降(jiang)低固體雜(za)質(zhi)含(han)量，即(ji)采用(yong)(yong)(yong)除雜(za)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)。在(zai)腐蝕(shi)性介質(zhi)中，密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)必須確保(bao)主(zhu)(zhu)密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)降(jiang)低腐蝕(shi)速率或消除腐蝕(shi)，即(ji)使用(yong)(yong)(yong)流體而不(bu)是堵塞流體系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)；在(zai)高壓密(mi)封(feng)(feng)(feng)(feng)(feng)(feng)裝置中，輔助系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)應(ying)(ying)確保(bao)多(duo)級降(jiang)壓和其他措施，即(ji)壓力控(kong)制系(xi)(xi)(xi)(xi)(xi)統(tong)(tong)。

　　定襄機械密封的三個主要(yao)功能如(ru)下(xia)：

　　1、沖洗功能，沖洗是定襄機械密封基本的功能，它直接將液體注入單面密封或雙面密封的高壓側。一般的定襄機械密封應該沖(chong)(chong)洗(xi)，特別是(shi)對于輕烴泵，沖(chong)(chong)洗(xi)時達(da)到隔離介質、冷卻和改善(shan)潤滑的(de)(de)目的(de)(de)。隔離介質的(de)(de)目的(de)(de)可以通(tong)過將與介質相容的(de)(de)液體引(yin)入密封腔進(jin)行外部循(xun)環(huan)沖(chong)(chong)洗(xi)來實(shi)現。

　　2、除雜和過濾功能，密封流體中的微細固體粒子、污垢等雜質對定襄機械密封造成的(de)(de)危害非常嚴重(zhong)，可(ke)能(neng)導致密(mi)封(feng)端面的(de)(de)磨損(sun)，也(ye)可(ke)能(neng)堵(du)塞寒冷(leng)密(mi)封(feng)系統的(de)(de)管線。密(mi)封(feng)性(xing)系統軟(ruan)件具有去除殘(can)(can)渣、保持液(ye)體(ti)(ti)清潔的(de)(de)作(zuo)用(yong)。當殘(can)(can)渣的(de)(de)相對密(mi)度(du)小于(yu)液(ye)體(ti)(ti)媒質相對密(mi)度(du)時(shi)，能(neng)用(yong)過濾裝置去除殘(can)(can)渣；而當殘(can)(can)渣的(de)(de)相對密(mi)度(du)超過液(ye)體(ti)(ti)媒質相對密(mi)度(du)時(shi)，可(ke)選用(yong)旋液(ye)分離設(she)備或網(wang)式過濾器(qi)去除殘(can)(can)渣。

　　3、流體替代功能，含有固體顆粒的氣相介質和液相介質的直接密封難度很大，它們溫、毒、貴、易蒸發、易結晶。借助定襄機械密封可以用雙端定襄機械密封代替(ti)密封介(jie)質，將難以直接密封的(de)介(jie)質轉化為密封潤(run)滑性能(neng)好、清潔的(de)密封液體(ti)介(jie)質。