三通(tong)(tong)(tong)閥門(men)(men)(men)與二通(tong)(tong)(tong)閥門(men)(men)(men)外觀上最明顯(xian)的差別，就是多一個流道口。三通(tong)(tong)(tong)閥門(men)(men)(men)主要(yao)用于改變(bian)(bian)介質流向(xiang)，三通(tong)(tong)(tong)閥門(men)(men)(men)它除了進口A、出口B、還(huan)有(you)換向(xiang)口C，普(pu)通(tong)(tong)(tong)閥門(men)(men)(men)是不(bu)具備改變(bian)(bian)介質流向(xiang)功能。

三通閥門(men)(men)其(qi)工作過程 ：閥門(men)(men)打(da)開(kai)介(jie)質(zhi)(zhi)(zhi)從(cong)A進入(ru)閥門(men)(men)，經B流出閥門(men)(men)，當旁路需要介(jie)質(zhi)(zhi)(zhi)流入(ru)時，開(kai)啟(qi)執行機構，閥芯(xin)換(huan)向(xiang)，介(jie)質(zhi)(zhi)(zhi)A進C出，當管線不需要介(jie)質(zhi)(zhi)(zhi)流入(ru)時，開(kai)啟(qi)執行機構°，閥門(men)(men)關閉截斷介(jie)質(zhi)(zhi)(zhi)。