平遠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。在平遠機械密封系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)中(zhong)(zhong)，上述系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)并不同時包括在內。密(mi)(mi)(mi)封(feng)(feng)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)選(xuan)擇主(zhu)要取決于(yu)(yu)主(zhu)密(mi)(mi)(mi)封(feng)(feng)件的(de)(de)應(ying)用(yong)范圍。例如(ru)，如(ru)果主(zhu)密(mi)(mi)(mi)封(feng)(feng)用(yong)于(yu)(yu)高溫(wen)液體，密(mi)(mi)(mi)封(feng)(feng)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)應(ying)確(que)(que)保降(jiang)(jiang)低(di)主(zhu)密(mi)(mi)(mi)封(feng)(feng)的(de)(de)環境溫(wen)度(du)，即(ji)采用(yong)溫(wen)度(du)控(kong)制系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)。如(ru)果主(zhu)密(mi)(mi)(mi)封(feng)(feng)用(yong)于(yu)(yu)固體雜質(zhi)含(han)(han)量高的(de)(de)工作介質(zhi)，密(mi)(mi)(mi)封(feng)(feng)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)應(ying)確(que)(que)保在主(zhu)密(mi)(mi)(mi)封(feng)(feng)前降(jiang)(jiang)低(di)固體雜質(zhi)含(han)(han)量，即(ji)采用(yong)除雜系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)。在腐(fu)蝕(shi)性介質(zhi)中(zhong)(zhong)，密(mi)(mi)(mi)封(feng)(feng)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)必須確(que)(que)保主(zhu)密(mi)(mi)(mi)封(feng)(feng)降(jiang)(jiang)低(di)腐(fu)蝕(shi)速率或消除腐(fu)蝕(shi)，即(ji)使用(yong)流(liu)體而不是堵塞流(liu)體系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)；在高壓(ya)密(mi)(mi)(mi)封(feng)(feng)裝(zhuang)置中(zhong)(zhong)，輔助系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)應(ying)確(que)(que)保多級降(jiang)(jiang)壓(ya)和其(qi)他措施，即(ji)壓(ya)力(li)控(kong)制系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)。

　　平遠機械密封的(de)三個主要功能(neng)如下：

　　1、沖洗功能，沖洗是平遠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。一般的平遠機械密封應該沖洗(xi)，特別是對于輕烴泵(beng)，沖洗(xi)時達到隔離介質(zhi)(zhi)、冷卻和(he)改(gai)善潤滑的目的。隔離介質(zhi)(zhi)的目的可以通過(guo)將與介質(zhi)(zhi)相容的液(ye)體引(yin)入密封腔進行外部循(xun)環沖洗(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、污垢等雜質對平遠機械密封造成的危害非常(chang)嚴(yan)重(zhong)，可能導致(zhi)密(mi)封端面(mian)的磨損，也可能堵塞寒冷密(mi)封系統的管線。密(mi)封性系統軟(ruan)件具有去除(chu)殘渣、保(bao)持液(ye)(ye)體清潔的作(zuo)用(yong)(yong)。當殘渣的相(xiang)對(dui)密(mi)度小于液(ye)(ye)體媒質相(xiang)對(dui)密(mi)度時(shi)，能用(yong)(yong)過濾裝(zhuang)置去除(chu)殘渣；而當殘渣的相(xiang)對(dui)密(mi)度超過液(ye)(ye)體媒質相(xiang)對(dui)密(mi)度時(shi)，可選(xuan)用(yong)(yong)旋液(ye)(ye)分離設備或網式過濾器去除(chu)殘渣。

　　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。借助平遠機械密封可以用雙端平遠機械密封代替密(mi)封(feng)介質，將難以直接(jie)密(mi)封(feng)的(de)介質轉化為(wei)密(mi)封(feng)潤(run)滑性能好(hao)、清潔的(de)密(mi)封(feng)液體介質。