在使用過程中，大多數麻涌鎮機械密封都屬于接觸式密封，其機理是靠動密封環與靜密封環的接觸端面在密封流體壓力和彈性元件壓緊力的作用下緊密貼合，并相對滑動而達到密封。工作時，麻涌鎮機械密封端面上同時發生摩擦、滑動與磨損等現象，摩擦是它的基本特征。麻涌鎮機械密封端面(mian)(mian)摩(mo)擦的(de)(de)(de)工況一般分(fen)為：流體摩(mo)擦、混合摩(mo)擦和邊界(jie)摩(mo)擦三類(lei)，但不能(neng)長(chang)時間(jian)干摩(mo)擦。干摩(mo)擦狀(zhuang)態時，兩端面(mian)(mian)間(jian)的(de)(de)(de)固體表(biao)面(mian)(mian)微凸體將直(zhi)接(jie)接(jie)觸而引起劇烈(lie)的(de)(de)(de)磨(mo)損。磨(mo)損時一方(fang)面(mian)(mian)會使(shi)摩(mo)擦表(biao)面(mian)(mian)物質(zhi)喪(sang)失或遷移，導(dao)致表(biao)面(mian)(mian)損壞；另(ling)一方(fang)面(mian)(mian)會產生大量的(de)(de)(de)摩(mo)擦熱(re)直(zhi)至燒毀(hui)密封。在無流體介質(zhi)的(de)(de)(de)工況下，如何減(jian)少磨(mo)損降低摩(mo)擦熱(re)，那就要依(yi)靠(kao)干磨(mo)密封了。

　　干(gan)磨(mo)(mo)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)屬(shu)于浮(fu)動(dong)(dong)(dong)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)的一種，常(chang)用(yong)(yong)材質為(wei)耐磨(mo)(mo)碳(tan)精，結構包(bao)括(kuo)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)行(xing)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)腔(qiang)體(ti)和環(huan)(huan)(huan)(huan)(huan)(huan)(huan)行(xing)軸(zhou)(zhou)套，密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)腔(qiang)體(ti)內有(you)(you)(you)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)行(xing)槽，槽內至少裝(zhuang)有(you)(you)(you)二個截面(mian)(mian)為(wei)矩形的環(huan)(huan)(huan)(huan)(huan)(huan)(huan)行(xing)石墨密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)，石墨密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)的內徑與(yu)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)行(xing)軸(zhou)(zhou)套之(zhi)間有(you)(you)(you)0.01-0.04的間隙，軸(zhou)(zhou)套外(wai)(wai)(wai)(wai)表面(mian)(mian)涂有(you)(you)(you)耐磨(mo)(mo)涂層，涂層材料一般為(wei)三氧化(hua)二鋁(lv)或三氧化(hua)二鉻。干(gan)磨(mo)(mo)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)有(you)(you)(you)時需要(yao)(yao)增加隔離(li)氣(qi)，通常(chang)使(shi)(shi)用(yong)(yong)氮氣(qi)，氮氣(qi)耗量能控制在25-40。主(zhu)要(yao)(yao)應(ying)用(yong)(yong)于密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)易燃有(you)(you)(you)毒介質，由于操作維修(xiu)簡單，密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)性(xing)好，不需要(yao)(yao)復雜的潤滑(hua)冷卻系統，可(ke)以(yi)干(gan)運行(xing)，得(de)到(dao)廣泛的應(ying)用(yong)(yong)。干(gan)磨(mo)(mo)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)包(bao)括(kuo)有(you)(you)(you)外(wai)(wai)(wai)(wai)罩及(ji)(ji)架設(she)于外(wai)(wai)(wai)(wai)罩上且可(ke)呈相對旋轉及(ji)(ji)貼(tie)合的動(dong)(dong)(dong)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)及(ji)(ji)靜(jing)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)，靜(jing)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)與(yu)外(wai)(wai)(wai)(wai)罩固定連接，靜(jing)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)及(ji)(ji)動(dong)(dong)(dong)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)上分開設(she)有(you)(you)(you)供旋轉軸(zhou)(zhou)安裝(zhuang)的通孔(kong)，且動(dong)(dong)(dong)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)與(yu)靜(jing)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)貼(tie)合的端面(mian)(mian)分別為(wei)動(dong)(dong)(dong)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)面(mian)(mian)及(ji)(ji)靜(jing)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)面(mian)(mian)，外(wai)(wai)(wai)(wai)罩上設(she)有(you)(you)(you)促使(shi)(shi)動(dong)(dong)(dong)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)與(yu)靜(jing)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)(huan)緊密(mi)(mi)(mi)(mi)貼(tie)合的彈性(xing)抵壓件。除了要(yao)(yao)保(bao)持密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)面(mian)(mian)平行(xing)之(zhi)外(wai)(wai)(wai)(wai)，主(zhu)要(yao)(yao)是摩擦副的材料問(wen)題。

　　摩(mo)擦材料(liao)應具備下列條件：

　　(1)機(ji)械(xie)強度高，能耐(nai)壓和耐(nai)壓力變(bian)形；

　　(2)具有耐(nai)干磨性，耐(nai)高載荷性，自潤滑性好；

　　(3)配(pei)對(dui)材(cai)料(liao)的磨(mo)合性好，無過大的磨(mo)損和對(dui)偶腐蝕；

　　(4)耐磨(mo)性好，摩擦材料雖然是易損(sun)件，起到保護制動(dong)(dong)或傳動(dong)(dong)裝置的(de)作用(yong)(yong)，但要(yao)求具有一定的(de)耐磨(mo)性，使用(yong)(yong)壽命盡量要(yao)長，刮傷、腐蝕和粘(zhan)附對偶，都會造成制動(dong)(dong)或傳動(dong)(dong)的(de)震動(dong)(dong)和不穩定；

　　(5)導熱(re)(re)性(xing)和散熱(re)(re)性(xing)好，導熱(re)(re)性(xing)是傳(chuan)導熱(re)(re)量(liang)的(de)能力大小，即包(bao)括吸熱(re)(re)，也包(bao)括散熱(re)(re)，所以，導熱(re)(re)性(xing)好的(de)必然散熱(re)(re)性(xing)也好；

　　(6)抗熱裂性(xing)好，根(gen)本解決抗熱裂性(xing)問(wen)題可能需要改(gai)變封孔方法；

　　(7)耐(nai)腐蝕性(xing)強，一些有色金(jin)屬(shu)合(he)金(jin)能將良好的(de)摩擦(ca)學(xue)特(te)性(xing)與有些流體的(de)耐(nai)腐蝕性(xing)結合(he)；

　　(8)線膨脹系(xi)數小，熱膨脹會造成摩擦材料與摩擦對偶之間的間隙過小，發生拖摩，損毀制(zhi)動(dong)、傳動(dong)裝置。