填(tian)(tian)(tian)(tian)料(liao)改集(ji)式密(mi)封是指(zhi)通(tong)過預緊(jin)或介質壓(ya)力的(de)(de)自(zi)緊(jin)作用(yong)(yong)使填(tian)(tian)(tian)(tian)料(liao)與轉動件及(ji)固(gu)定(ding)(ding)件之間產生壓(ya)緊(jin)力的(de)(de)動密(mi)封裝置。又稱“填(tian)(tian)(tian)(tian)料(liao)函(han)密(mi)封”。結構形(xing)式較多(duo)(duo)，主要由填(tian)(tian)(tian)(tian)料(liao)、填(tian)(tian)(tian)(tian)料(liao)箱和(he)填(tian)(tian)(tian)(tian)料(liao)固(gu)定(ding)(ding)件組成(cheng)。常用(yong)(yong)的(de)(de)填(tian)(tian)(tian)(tian)料(liao)材料(liao)有(you)石棉織物、碳纖(xian)維(wei)、橡(xiang)膠(jiao)、柔性石墨和(he)工(gong)程塑料(liao)等(deng)(deng)，預制成(cheng)環狀(zhuang)(zhuang)或條狀(zhuang)(zhuang)（有(you)的(de)(de)需預先(xian)浸漬潤滑性好的(de)(de)填(tian)(tian)(tian)(tian)充物），并(bing)采用(yong)(yong)多(duo)(duo)環或螺(luo)旋(xuan)狀(zhuang)(zhuang)多(duo)(duo)層(ceng)結構。填(tian)(tian)(tian)(tian)料(liao)箱用(yong)(yong)以安置填(tian)(tian)(tian)(tian)料(liao)。填(tian)(tian)(tian)(tian)料(liao)固(gu)定(ding)(ding)件包括壓(ya)蓋、螺(luo)栓和(he)彈簧等(deng)(deng)，用(yong)(yong)以使填(tian)(tian)(tian)(tian)料(liao)預緊(jin)，工(gong)作時阻止介質外漏(lou)，彈簧可起補償作用(yong)(yong)。

　　填(tian)料(liao)裝(zhuang)入填(tian)料(liao)腔以后，經壓(ya)(ya)蓋(gai)螺絲對它作軸向壓(ya)(ya)縮，當(dang)軸與(yu)填(tian)料(liao)有相對運動(dong)時(shi)，由于填(tian)料(liao)的塑(su)性(xing)，使它產(chan)生(sheng)徑(jing)向力，并(bing)與(yu)軸緊(jin)密(mi)(mi)接(jie)觸(chu)(chu)。與(yu)此同(tong)時(shi)，填(tian)料(liao)中浸漬的潤滑(hua)劑被擠出，在接(jie)觸(chu)(chu)面之(zhi)間形(xing)成(cheng)(cheng)(cheng)油(you)膜。由于接(jie)觸(chu)(chu)狀態并(bing)不是(shi)特(te)別均勻的，接(jie)觸(chu)(chu)部(bu)(bu)(bu)位便出現“邊界(jie)潤滑(hua)”狀態，稱(cheng)為“軸承效(xiao)(xiao)應”；而未(wei)接(jie)觸(chu)(chu)的凹(ao)部(bu)(bu)(bu)形(xing)成(cheng)(cheng)(cheng)小油(you)槽，有較厚的油(you)膜，接(jie)觸(chu)(chu)部(bu)(bu)(bu)位與(yu)非接(jie)觸(chu)(chu)部(bu)(bu)(bu)位組成(cheng)(cheng)(cheng)一(yi)道不規則的迷(mi)(mi)宮，起(qi)阻(zu)止液流(liu)泄(xie)漏的作用，此稱(cheng)“迷(mi)(mi)宮效(xiao)(xiao)應”。這就是(shi)填(tian)料(liao)密(mi)(mi)封的機(ji)理。顯然，良好的密(mi)(mi)封在于維持(chi)“軸承效(xiao)(xiao)應”和(he)“迷(mi)(mi)宮效(xiao)(xiao)應”。也就是(shi)說，要保持(chi)良好的潤滑(hua)和(he)適(shi)當(dang)的壓(ya)(ya)緊(jin)。若潤滑(hua)不良，或壓(ya)(ya)得過緊(jin)都會(hui)使油(you)膜中斷，造成(cheng)(cheng)(cheng)填(tian)料(liao)與(yu)軸之(zhi)間出現干摩擦，最后導致燒軸和(he)出現嚴(yan)重磨損。

　　為(wei)此(ci)，需要經常(chang)對填(tian)料的(de)(de)壓(ya)(ya)緊程度(du)進行調整(zheng)，以便(bian)填(tian)料中的(de)(de)潤滑(hua)劑在(zai)運行一(yi)段時(shi)間流失之(zhi)后(hou)，再擠(ji)出一(yi)些潤滑(hua)劑，同(tong)時(shi)補償(chang)填(tian)料因(yin)體積變(bian)化所(suo)(suo)造(zao)成的(de)(de)壓(ya)(ya)緊力(li)松(song)弛(chi)。顯然，這樣經常(chang)擠(ji)壓(ya)(ya)填(tian)料，最終將使浸漬(zi)劑枯竭，所(suo)(suo)以定期更換填(tian)料是必要的(de)(de)。此(ci)外，為(wei)了維持液膜和帶走摩(mo)擦熱，有意讓(rang)填(tian)料處有少量泄(xie)漏也是必要的(de)(de)。