活套法(fa)蘭是(shi)指(zhi)松(song)套于容(rong)器或(huo)(huo)管(guan)(guan)道突(tu)緣(yuan)(yuan)的一種(zhong)法(fa)蘭。屬松(song)式(shi)(shi)法(fa)蘭。突(tu)緣(yuan)(yuan)可(ke)采(cai)(cai)用(yong)(yong)翻邊、直(zhi)接(jie)車出(chu)或(huo)(huo)另外(wai)焊接(jie)圓(yuan)環等方(fang)式(shi)(shi)制成。優點是(shi)法(fa)蘭變形時對容(rong)器或(huo)(huo)管(guan)(guan)道不(bu)產生附加力(li)矩，制造方(fang)便(bian)，可(ke)采(cai)(cai)用(yong)(yong)與容(rong)器或(huo)(huo)管(guan)(guan)道不(bu)同的材料(liao)制造，便(bian)于節省(sheng)貴重金(jin)屬。缺(que)點是(shi)法(fa)蘭厚度較大。適(shi)用(yong)(yong)于容(rong)器或(huo)(huo)管(guan)(guan)道內襯有(you)脆性材料(liao)且壓力(li)不(bu)高的場合。