調節閥故障幾種保位方案來解決
時間：2018.11.07 瀏覽1751次
調節閥在(zai)(zai)過(guo)程(cheng)(cheng)控(kong)(kong)制中的(de)作用(yong)是人(ren)所共知(zhi)的(de)，在(zai)(zai)許(xu)多控(kong)(kong)制過(guo)程(cheng)(cheng)中 要(yao)(yao)求調節閥在(zai)(zai)故障時(shi)(shi)(shi)處(chu)于某一(yi)個(ge)位(wei)置(zhi)，以(yi)保(bao)護工(gong)藝過(guo)程(cheng)(cheng)不出(chu)現事故，這就要(yao)(yao)求調節閥在(zai)(zai)設計上實(shi)現故障—安(an)全(quan)的(de)三 斷(duan)(斷(duan)氣、斷(duan)電(dian)、斷(duan)信號)保(bao)護措(cuo)施。對于電(dian)動(dong)(dong)調節閥來說(shuo)，比較簡單，斷(duan)信號時(shi)(shi)(shi)，可(ke)以(yi)根據(ju)控(kong)(kong)制模塊的(de)設定而停(ting)留(liu) 在(zai)(zai)全(quan)開(kai)、全(quan)關、保(bao)持中的(de)任一(yi)位(wei)置(zhi)，而斷(duan)電(dian)時(shi)(shi)(shi)，自然停(ting)留(liu)在(zai)(zai)故障位(wei)置(zhi)，或帶有復(fu)位(wei)裝置(zhi)的(de)電(dian)動(dong)(dong)執行(xing)(xing)器也可(ke)將(jiang)閥位(wei)運(yun) 行(xing)(xing)到全(quan)開(kai)或全(quan)關。
對(dui)于(yu)氣(qi)(qi)動(dong)調節閥(fa)(fa)來說，情況就(jiu)比較復雜了，所以我(wo)(wo) 們主要(yao)(yao)討論氣(qi)(qi)動(dong)調節閥(fa)(fa)的(de)三斷(duan)保(bao)位(wei)方(fang)(fang)法。一般(ban)來說，我(wo)(wo)們在選擇氣(qi)(qi)動(dong)薄膜調節閥(fa)(fa)時(shi)，都要(yao)(yao)先確定選氣(qi)(qi)開還(huan)是(shi)氣(qi)(qi)閉(bi)， 這(zhe)就(jiu)是(shi)選擇調節閥(fa)(fa)斷(duan)氣(qi)(qi)時(shi)的(de)保(bao)護(hu)位(wei)置，如(ru)果工藝(yi)要(yao)(yao)求(qiu)斷(duan)氣(qi)(qi)時(shi)閥(fa)(fa)門(men)打(da)開，則(ze)選擇常開(氣(qi)(qi)閉(bi))式調節閥(fa)(fa)，反之則(ze)選常閉(bi) (氣(qi)(qi)開)式調節閥(fa)(fa)。這(zhe)只(zhi)是(shi)一個粗淺的(de)方(fang)(fang)案，如(ru)果工藝(yi)要(yao)(yao)求(qiu)斷(duan)氣(qi)(qi)、斷(duan)電(dian)、斷(duan)信(xin)號的(de)三斷(duan)保(bao)護(hu)，則(ze)調節閥(fa)(fa)就(jiu)需要(yao)(yao)配(pei)置一 些(xie)附件來組成一個保(bao)護(hu)系統才能實現控制要(yao)(yao)求(qiu)，這(zhe)些(xie)附件主要(yao)(yao)有保(bao)位(wei)閥(fa)(fa)、電(dian)磁閥(fa)(fa)、氣(qi)(qi)罐等。以下是(shi)單作用(yong)氣(qi)(qi)動(dong)薄膜 調節閥(fa)(fa)和雙作用(yong)氣(qi)(qi)動(dong)調節閥(fa)(fa)的(de)兩種保(bao)位(wei)方(fang)(fang)案。
一、氣(qi)動薄(bo)膜調節(jie)閥(fa)方 案（調節(jie)閥(fa)配用(yong)電(dian)－氣(qi)閥(fa)門定(ding)位器）
本方案主要由氣動(dong)調節閥、電(dian)- 氣閥門定位器(qi)、失(shi)電(dian)(信(xin)號)比較器(qi)、單電(dian)控(kong)電(dian)磁換向閥、氣動(dong)保位閥、閥位信(xin)號返回器(qi)等組成。其工作(zuo)原理如(ru)下：
1、斷氣(qi)源：當控(kong)制系統(tong)氣(qi)源故(gu)障(失(shi)氣(qi))時，氣(qi)動(dong)保(bao)位(wei)(wei)閥自動(dong)關(guan)閉將 定(ding)位(wei)(wei)器的(de)(de)輸出信(xin)號(hao)壓(ya)力(li)鎖定(ding)在氣(qi)動(dong)控(kong)制閥的(de)(de)膜室(shi)內，輸出信(xin)號(hao)壓(ya)力(li)與(yu)控(kong)制閥彈簧產生的(de)(de)反(fan)力(li)相平衡，氣(qi)動(dong)控(kong)制閥的(de)(de) 閥位(wei)(wei)保(bao)持(chi)在故(gu)障位(wei)(wei)置。該保(bao)位(wei)(wei)閥應設定(ding)在略(lve)低(di)于氣(qi)源的(de)(de)最(zui)小值時啟動(dong)。
2、斷電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源：當控(kong)(kong)制(zhi)系統電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源故(gu)障(zhang)(失(shi)(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian))時，失(shi)(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(信(xin)(xin)(xin)號)比較(jiao)器控(kong)(kong)制(zhi) 單(dan)(dan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)換(huan)向閥(fa)(fa)(fa)(fa)(fa)的(de)(de)(de)輸(shu)(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓消(xiao)失(shi)(shi)(shi)(shi)，單(dan)(dan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)換(huan)向閥(fa)(fa)(fa)(fa)(fa)失(shi)(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，單(dan)(dan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)換(huan)向閥(fa)(fa)(fa)(fa)(fa)內的(de)(de)(de)滑閥(fa)(fa)(fa)(fa)(fa)在(zai)復位彈簧(huang)的(de)(de)(de)作(zuo)用(yong)下滑動 ，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)(fa)換(huan)向，將氣(qi)動保位閥(fa)(fa)(fa)(fa)(fa)的(de)(de)(de)膜(mo)室壓力排空，氣(qi)動保位閥(fa)(fa)(fa)(fa)(fa)關閉，將定位器的(de)(de)(de)輸(shu)(shu)出信(xin)(xin)(xin)號壓力鎖定在(zai)氣(qi)動控(kong)(kong)制(zhi)閥(fa)(fa)(fa)(fa)(fa)的(de)(de)(de)膜(mo) 室內，輸(shu)(shu)出信(xin)(xin)(xin)號壓力與控(kong)(kong)制(zhi)閥(fa)(fa)(fa)(fa)(fa)彈簧(huang)產生(sheng)的(de)(de)(de)反力相平衡(heng)，氣(qi)動控(kong)(kong)制(zhi)閥(fa)(fa)(fa)(fa)(fa)的(de)(de)(de)閥(fa)(fa)(fa)(fa)(fa)位保持(chi)在(zai)故(gu)障(zhang)位置。
3、斷(duan)信(xin)號(hao)(hao)：當控(kong)制(zhi)(zhi)系統(tong)信(xin)號(hao)(hao)故障(失信(xin)號(hao)(hao))時，失電(信(xin)號(hao)(hao))比較器檢 測到后，斷(duan)掉(diao)單電控(kong)電磁(ci)換(huan)向(xiang)閥的電壓信(xin)號(hao)(hao)，單電控(kong)電磁(ci)換(huan)向(xiang)閥失電，單電控(kong)電磁(ci)換(huan)向(xiang)閥內的滑閥在(zai)復位(wei)彈簧(huang)的作 用下滑動，電磁(ci)閥換(huan)向(xiang)，將(jiang)氣(qi)(qi)動保位(wei)閥的膜室壓力(li)排(pai)空，氣(qi)(qi)動保位(wei)閥關閉，將(jiang)定(ding)位(wei)器的輸出信(xin)號(hao)(hao)壓力(li)鎖定(ding)在(zai)氣(qi)(qi)動控(kong) 制(zhi)(zhi)閥的膜室內，輸出信(xin)號(hao)(hao)壓力(li)與(yu)控(kong)制(zhi)(zhi)閥彈簧(huang)產生(sheng)的反力(li)相(xiang)平衡，氣(qi)(qi)動控(kong)制(zhi)(zhi)閥的閥位(wei)保持(chi)在(zai)故障位(wei)置。
