在使用過程中，大多數德清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，德清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。德清機械密封端面(mian)(mian)摩(mo)(mo)擦(ca)的(de)工況一(yi)般(ban)分為：流(liu)體摩(mo)(mo)擦(ca)、混合摩(mo)(mo)擦(ca)和邊界摩(mo)(mo)擦(ca)三類(lei)，但不能長時間(jian)干摩(mo)(mo)擦(ca)。干摩(mo)(mo)擦(ca)狀態(tai)時，兩端面(mian)(mian)間(jian)的(de)固體表(biao)(biao)面(mian)(mian)微凸體將直(zhi)接接觸而引起劇烈的(de)磨(mo)損。磨(mo)損時一(yi)方面(mian)(mian)會(hui)使摩(mo)(mo)擦(ca)表(biao)(biao)面(mian)(mian)物質喪失(shi)或遷移(yi)，導致表(biao)(biao)面(mian)(mian)損壞(huai)；另(ling)一(yi)方面(mian)(mian)會(hui)產生大量的(de)摩(mo)(mo)擦(ca)熱(re)(re)直(zhi)至燒毀密封。在(zai)無流(liu)體介質的(de)工況下，如何減少(shao)磨(mo)損降低摩(mo)(mo)擦(ca)熱(re)(re)，那(nei)就要依靠干磨(mo)密封了(le)。

　　干(gan)磨(mo)(mo)(mo)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)屬于(yu)浮動密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)的(de)(de)(de)(de)(de)一種，常(chang)用(yong)材(cai)質為(wei)耐磨(mo)(mo)(mo)碳精(jing)，結構包(bao)括環(huan)(huan)(huan)(huan)(huan)(huan)行(xing)(xing)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)腔(qiang)體和環(huan)(huan)(huan)(huan)(huan)(huan)行(xing)(xing)軸(zhou)套(tao)，密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)腔(qiang)體內有(you)(you)環(huan)(huan)(huan)(huan)(huan)(huan)行(xing)(xing)槽，槽內至少(shao)裝有(you)(you)二(er)(er)個截面為(wei)矩形(xing)的(de)(de)(de)(de)(de)環(huan)(huan)(huan)(huan)(huan)(huan)行(xing)(xing)石(shi)墨(mo)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)，石(shi)墨(mo)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)的(de)(de)(de)(de)(de)內徑(jing)與(yu)環(huan)(huan)(huan)(huan)(huan)(huan)行(xing)(xing)軸(zhou)套(tao)之間有(you)(you)0.01-0.04的(de)(de)(de)(de)(de)間隙(xi)，軸(zhou)套(tao)外(wai)(wai)(wai)表面涂(tu)有(you)(you)耐磨(mo)(mo)(mo)涂(tu)層(ceng)，涂(tu)層(ceng)材(cai)料(liao)一般為(wei)三氧(yang)化二(er)(er)鋁或三氧(yang)化二(er)(er)鉻。干(gan)磨(mo)(mo)(mo)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)有(you)(you)時需要(yao)增加隔離氣(qi)，通常(chang)使(shi)(shi)用(yong)氮氣(qi)，氮氣(qi)耗量能控制在25-40。主(zhu)要(yao)應用(yong)于(yu)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)易燃有(you)(you)毒介質，由于(yu)操作(zuo)維修簡單，密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)性(xing)好，不需要(yao)復雜的(de)(de)(de)(de)(de)潤滑(hua)冷卻(que)系統，可(ke)以干(gan)運行(xing)(xing)，得到(dao)廣泛的(de)(de)(de)(de)(de)應用(yong)。干(gan)磨(mo)(mo)(mo)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)包(bao)括有(you)(you)外(wai)(wai)(wai)罩(zhao)及架(jia)設(she)于(yu)外(wai)(wai)(wai)罩(zhao)上(shang)且(qie)可(ke)呈(cheng)相對旋(xuan)轉(zhuan)(zhuan)及貼合(he)的(de)(de)(de)(de)(de)動密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)及靜(jing)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)，靜(jing)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)與(yu)外(wai)(wai)(wai)罩(zhao)固定(ding)連接，靜(jing)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)及動密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)上(shang)分(fen)開設(she)有(you)(you)供(gong)旋(xuan)轉(zhuan)(zhuan)軸(zhou)安(an)裝的(de)(de)(de)(de)(de)通孔(kong)，且(qie)動密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)與(yu)靜(jing)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)貼合(he)的(de)(de)(de)(de)(de)端(duan)面分(fen)別(bie)為(wei)動密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)面及靜(jing)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)面，外(wai)(wai)(wai)罩(zhao)上(shang)設(she)有(you)(you)促(cu)使(shi)(shi)動密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)與(yu)靜(jing)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)環(huan)(huan)(huan)(huan)(huan)(huan)緊密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)貼合(he)的(de)(de)(de)(de)(de)彈性(xing)抵壓件。除了要(yao)保(bao)持密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)面平行(xing)(xing)之外(wai)(wai)(wai)，主(zhu)要(yao)是(shi)摩擦(ca)副(fu)的(de)(de)(de)(de)(de)材(cai)料(liao)問題。

　　摩(mo)擦材(cai)料(liao)應具備下列條件：

　　(1)機械強度高，能(neng)耐壓和耐壓力變(bian)形；

　　(2)具有耐(nai)干磨性(xing)，耐(nai)高載荷性(xing)，自潤滑性(xing)好；

　　(3)配對(dui)材(cai)料的磨合(he)性好(hao)，無過大的磨損和對(dui)偶(ou)腐蝕；

　　(4)耐磨性好，摩擦(ca)材料(liao)雖(sui)然是易損(sun)件，起(qi)到(dao)保護制(zhi)動(dong)(dong)或傳動(dong)(dong)裝(zhuang)置(zhi)的作用，但要求具(ju)有一定的耐磨性，使用壽命盡量要長(chang)，刮傷、腐蝕和粘附對偶，都(dou)會造成制(zhi)動(dong)(dong)或傳動(dong)(dong)的震動(dong)(dong)和不(bu)穩(wen)定；

　　(5)導(dao)熱(re)(re)性(xing)和散(san)(san)熱(re)(re)性(xing)好，導(dao)熱(re)(re)性(xing)是傳導(dao)熱(re)(re)量的能力(li)大小，即(ji)包(bao)(bao)括(kuo)吸熱(re)(re)，也包(bao)(bao)括(kuo)散(san)(san)熱(re)(re)，所以，導(dao)熱(re)(re)性(xing)好的必(bi)然(ran)散(san)(san)熱(re)(re)性(xing)也好；

　　(6)抗(kang)熱裂性(xing)好，根(gen)本解決抗(kang)熱裂性(xing)問(wen)題可(ke)能需要(yao)改(gai)變封(feng)孔(kong)方法；

　　(7)耐(nai)腐(fu)蝕性(xing)強(qiang)，一些有(you)色金(jin)屬合(he)金(jin)能將良(liang)好的(de)摩擦學特性(xing)與(yu)有(you)些流體的(de)耐(nai)腐(fu)蝕性(xing)結合(he)；

　　(8)線膨脹(zhang)系數(shu)小，熱膨脹(zhang)會(hui)造成摩(mo)擦(ca)(ca)材料與摩(mo)擦(ca)(ca)對偶之間的間隙過小，發生(sheng)拖摩(mo)，損毀制動(dong)、傳動(dong)裝置(zhi)。