氣(qi)動(dong)閥(fa)門(men)(men)(men)是工業管道系統自動(dong)化的(de)一(yi)(yi)種(zhong)重要(yao)裝置，是在(zai)普(pu)通(tong)(tong)閥(fa)門(men)(men)(men)的(de)基礎上安裝氣(qi)動(dong)執(zhi)行(xing)(xing)(xing)器(qi)，通(tong)(tong)過(guo)氣(qi)源(yuan)壓力驅動(dong)執(zhi)行(xing)(xing)(xing)器(qi)工作。從閥(fa)門(men)(men)(men)的(de)運動(dong)方(fang)式一(yi)(yi)般(ban)分(fen)為：直行(xing)(xing)(xing)程與角行(xing)(xing)(xing)程；從執(zhi)行(xing)(xing)(xing)器(qi)一(yi)(yi)般(ban)分(fen)為：單作用與雙作用。氣(qi)動(dong)閥(fa)門(men)(men)(men)通(tong)(tong)過(guo)輸出信號實現閥(fa)門(men)(men)(men)的(de)切斷(duan)、接通(tong)(tong)、調(diao)節等功能，一(yi)(yi)般(ban)氣(qi)動(dong)閥(fa)門(men)(men)(men)都配(pei)置電磁閥(fa)、氣(qi)源(yuan)三聯(lian)件、限位開關、定位器(qi)等配(pei)件一(yi)(yi)起使用。

氣動(dong)(dong)(dong)閥(fa)(fa)(fa)門(men)定位(wei)器(qi)是(shi)按力(li)(li)平(ping)衡原理設計(ji)工(gong)作(zuo)(zuo)(zuo)(zuo)的(de)(de)(de)(de)(de)(de)，其工(gong)作(zuo)(zuo)(zuo)(zuo)原理是(shi)按力(li)(li)平(ping)衡原理設計(ji)和工(gong)作(zuo)(zuo)(zuo)(zuo)的(de)(de)(de)(de)(de)(de)。當通(tong)入(ru)波紋管(guan)的(de)(de)(de)(de)(de)(de)信(xin)(xin)(xin)號壓力(li)(li)增(zeng)加時，使杠桿(gan)2繞支(zhi)(zhi)點轉動(dong)(dong)(dong)，檔板靠近噴(pen)嘴，噴(pen)嘴背壓經(jing)放大(da)器(qi)放大(da)后，送入(ru)薄膜執(zhi)(zhi)行(xing)(xing)機(ji)(ji)構氣室，使閥(fa)(fa)(fa)桿(gan)向(xiang)下移動(dong)(dong)(dong)，并(bing)帶動(dong)(dong)(dong)反(fan)饋(kui)桿(gan)（擺桿(gan)）繞支(zhi)(zhi)點轉動(dong)(dong)(dong)，連(lian)接在同一(yi)軸上(shang)(shang)(shang)的(de)(de)(de)(de)(de)(de)反(fan)饋(kui)凸(tu)輪(lun)(lun)（偏(pian)心凸(tu)輪(lun)(lun)）也跟著作(zuo)(zuo)(zuo)(zuo)逆時針方向(xiang)轉動(dong)(dong)(dong)，通(tong)過(guo)滾輪(lun)(lun)使杠桿(gan)1繞支(zhi)(zhi)點轉動(dong)(dong)(dong)，并(bing)將反(fan)饋(kui)彈(dan)簧(huang)拉(la)伸、彈(dan)簧(huang)對(dui)杠桿(gan)2的(de)(de)(de)(de)(de)(de)拉(la)力(li)(li)與信(xin)(xin)(xin)號壓力(li)(li)作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)在波紋管(guan)上(shang)(shang)(shang)的(de)(de)(de)(de)(de)(de)力(li)(li)達到力(li)(li)矩平(ping)衡時儀表(biao)達到平(ping)衡狀態。此(ci)時，一(yi)定的(de)(de)(de)(de)(de)(de)信(xin)(xin)(xin)號壓力(li)(li)就與一(yi)定的(de)(de)(de)(de)(de)(de)閥(fa)(fa)(fa)門(men)位(wei)置(zhi)相對(dui)應。 以(yi)上(shang)(shang)(shang)作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)方式為正作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)，若要改變(bian)作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)方式，只(zhi)要將凸(tu)輪(lun)(lun)翻轉，A向(xiang)變(bian)成B向(xiang)等，即(ji)可。 所謂正作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)定位(wei)器(qi)，就是(shi)信(xin)(xin)(xin)號壓力(li)(li)增(zeng)加，輸出壓力(li)(li)亦(yi)增(zeng)加；所謂反(fan)作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)定位(wei)器(qi)，就是(shi)信(xin)(xin)(xin)號壓力(li)(li)增(zeng)加，輸出壓力(li)(li)則(ze)減少。 一(yi)臺(tai)正作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)執(zhi)(zhi)行(xing)(xing)機(ji)(ji)構只(zhi)要裝上(shang)(shang)(shang)反(fan)作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)定位(wei)器(qi)，就能實(shi)現(xian)反(fan)作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)執(zhi)(zhi)行(xing)(xing)機(ji)(ji)構的(de)(de)(de)(de)(de)(de)動(dong)(dong)(dong)作(zuo)(zuo)(zuo)(zuo)；相反(fan)，一(yi)臺(tai)反(fan)作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)執(zhi)(zhi)行(xing)(xing)機(ji)(ji)構只(zhi)要裝上(shang)(shang)(shang)反(fan)作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)定位(wei)器(qi)，就能實(shi)現(xian)正作(zuo)(zuo)(zuo)(zuo)用(yong)(yong)(yong)(yong)執(zhi)(zhi)行(xing)(xing)機(ji)(ji)構的(de)(de)(de)(de)(de)(de)動(dong)(dong)(dong)作(zuo)(zuo)(zuo)(zuo)。