壓(ya)(ya)力(li)容(rong)(rong)器(qi)法蘭(lan)是(shi)(shi)(shi)壓(ya)(ya)力(li)容(rong)(rong)器(qi)的(de)(de)(de)常用部(bu)(bu)(bu)件，是(shi)(shi)(shi)連(lian)接(jie)(jie)各種壓(ya)(ya)力(li)容(rong)(rong)器(qi)部(bu)(bu)(bu)件的(de)(de)(de)基本元件，廣泛地用于石油、石化、電(dian)力(li)、原子(zi)能(neng)(neng)、輕工(gong)等領域。對(dui)于容(rong)(rong)器(qi)而言(yan)，應(ying)該是(shi)(shi)(shi)一(yi)個(ge)組件，包括(kuo)法蘭(lan)、墊(dian)片(pian)和(he)連(lian)接(jie)(jie)螺(luo)(luo)栓(shuan)或螺(luo)(luo)柱以及螺(luo)(luo)母，其(qi)作用是(shi)(shi)(shi)使不同的(de)(de)(de)受壓(ya)(ya)元件組合(he)在一(yi)起，同時保證(zheng)連(lian)接(jie)(jie)部(bu)(bu)(bu)位不發生(sheng)泄漏(lou)。法蘭(lan)連(lian)接(jie)(jie)的(de)(de)(de)主(zhu)要失效(xiao)形(xing)式為(wei)(wei)接(jie)(jie)頭的(de)(de)(de)剛度失效(xiao)，其(qi)外部(bu)(bu)(bu)表現型式為(wei)(wei)泄漏(lou)。壓(ya)(ya)力(li)容(rong)(rong)器(qi)內(nei)部(bu)(bu)(bu)的(de)(de)(de)介質具(ju)有(you)高溫、高壓(ya)(ya)的(de)(de)(de)特(te)點，同時具(ju)有(you)易燃、易爆的(de)(de)(de)特(te)性(xing)(xing)或毒性(xing)(xing)，一(yi)旦產(chan)生(sheng)泄漏(lou)，將發生(sheng)嚴(yan)重的(de)(de)(de)次生(sheng)災害，嚴(yan)重威脅壓(ya)(ya)力(li)容(rong)(rong)器(qi)本體和(he)周圍設(she)備以及人員的(de)(de)(de)安全。因此容(rong)(rong)器(qi)法蘭(lan)的(de)(de)(de)設(she)計和(he)選用應(ying)優先考慮的(de)(de)(de)因素(su)是(shi)(shi)(shi)整(zheng)體密封(feng)性(xing)(xing)能(neng)(neng)。

  我國(guo)壓(ya)力容器(qi)(qi)法(fa)蘭(lan)(lan)標(biao)準自成(cheng)體系(xi)。最早的(de)壓(ya)力容器(qi)(qi)法(fa)蘭(lan)(lan)標(biao)準可以追溯到20世(shi)紀70年代(dai)，當(dang)時使用(yong)的(de)是由原(yuan)一機部(bu)(bu)、石油(you)部(bu)(bu)、化工部(bu)(bu)三部(bu)(bu)共同發布的(de)壓(ya)力容器(qi)(qi)法(fa)蘭(lan)(lan)行(xing)業標(biao)準JB 1157~1164-1973.經(jing)過長期的(de)試用(yong)及不斷的(de)修訂(ding)，目前最新的(de)標(biao)準為NB/T 47020~47027-2012《壓(ya)力容器(qi)(qi)法(fa)蘭(lan)(lan)》。

  就(jiu)法(fa)(fa)蘭的結構型式(shi)和(he)工作(zuo)原理而(er)言，壓力容器(qi)法(fa)(fa)蘭和(he)管(guan)(guan)法(fa)(fa)蘭沒(mei)有多大(da)差異(yi)。比較明顯的區(qu)別是，壓力容器(qi)法(fa)(fa)蘭規格較大(da)，與各類壓力容器(qi)連接使用；而(er)管(guan)(guan)法(fa)(fa)蘭常常與管(guan)(guan)子直(zhi)接連接或與泵(beng)、閥、機(ji)等管(guan)(guan)道設備的進出口管(guan)(guan)子連接使用。

  壓(ya)(ya)(ya)(ya)力(li)(li)容(rong)器法蘭(lan)(lan)工(gong)(gong)作原理為：當(dang)(dang)對法蘭(lan)(lan)螺(luo)(luo)栓(shuan)(shuan)施(shi)加預緊(jin)(jin)力(li)(li)時(shi)，螺(luo)(luo)栓(shuan)(shuan)力(li)(li)通過法蘭(lan)(lan)環把墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)壓(ya)(ya)(ya)(ya)緊(jin)(jin)，迫使法蘭(lan)(lan)墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)產生壓(ya)(ya)(ya)(ya)縮(suo)(suo)變(bian)(bian)形。當(dang)(dang)螺(luo)(luo)栓(shuan)(shuan)力(li)(li)達到(dao)一定(ding)數(shu)值后，迫使法蘭(lan)(lan)密(mi)(mi)(mi)封(feng)(feng)面(mian)和墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)上的(de)(de)(de)(de)(de)凹凸不平面(mian)借助墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)變(bian)(bian)形而填滿，這就(jiu)為阻止(zhi)流(liu)體介(jie)質(zhi)泄漏創(chuang)造了初(chu)始密(mi)(mi)(mi)封(feng)(feng)條件。此時(shi)墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)單位有(you)效(xiao)密(mi)(mi)(mi)封(feng)(feng)面(mian)積上的(de)(de)(de)(de)(de)壓(ya)(ya)(ya)(ya)緊(jin)(jin)力(li)(li)稱為墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)的(de)(de)(de)(de)(de)初(chu)始密(mi)(mi)(mi)封(feng)(feng)比壓(ya)(ya)(ya)(ya)。當(dang)(dang)設(she)備或管道承受介(jie)質(zhi)壓(ya)(ya)(ya)(ya)力(li)(li)后，螺(luo)(luo)栓(shuan)(shuan)受到(dao)拉伸應力(li)(li)而伸長，法蘭(lan)(lan)密(mi)(mi)(mi)封(feng)(feng)面(mian)沿著彼此分離(li)的(de)(de)(de)(de)(de)方向移動，密(mi)(mi)(mi)封(feng)(feng)面(mian)與墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)之間的(de)(de)(de)(de)(de)壓(ya)(ya)(ya)(ya)緊(jin)(jin)力(li)(li)下(xia)(xia)降(jiang)，墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)的(de)(de)(de)(de)(de)壓(ya)(ya)(ya)(ya)縮(suo)(suo)量(liang)減少，預緊(jin)(jin)密(mi)(mi)(mi)封(feng)(feng)比壓(ya)(ya)(ya)(ya)下(xia)(xia)降(jiang)。如(ru)果這時(shi)密(mi)(mi)(mi)封(feng)(feng)墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)具(ju)有(you)足夠的(de)(de)(de)(de)(de)回彈能(neng)(neng)力(li)(li)，墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)的(de)(de)(de)(de)(de)變(bian)(bian)形能(neng)(neng)補償螺(luo)(luo)栓(shuan)(shuan)和密(mi)(mi)(mi)封(feng)(feng)面(mian)的(de)(de)(de)(de)(de)分離(li)值，而使預緊(jin)(jin)密(mi)(mi)(mi)封(feng)(feng)比壓(ya)(ya)(ya)(ya)只(zhi)下(xia)(xia)降(jiang)到(dao)不小(xiao)于工(gong)(gong)作密(mi)(mi)(mi)封(feng)(feng)比壓(ya)(ya)(ya)(ya)，則(ze)法蘭(lan)(lan)依然(ran)保持良好(hao)的(de)(de)(de)(de)(de)密(mi)(mi)(mi)封(feng)(feng)狀態。反之，如(ru)墊(dian)(dian)(dian)(dian)片(pian)(pian)(pian)(pian)的(de)(de)(de)(de)(de)回彈能(neng)(neng)力(li)(li)不足，密(mi)(mi)(mi)封(feng)(feng)比壓(ya)(ya)(ya)(ya)下(xia)(xia)降(jiang)到(dao)工(gong)(gong)作密(mi)(mi)(mi)封(feng)(feng)比壓(ya)(ya)(ya)(ya)以下(xia)(xia)，甚至(zhi)密(mi)(mi)(mi)封(feng)(feng)口重(zhong)新出現縫隙(xi)，則(ze)密(mi)(mi)(mi)封(feng)(feng)失(shi)效(xiao)。