調節閥故障幾種保位方案來解決
時間：2018.11.07 瀏覽1874次
調(diao)(diao)節(jie)閥(fa)(fa)在(zai)過程控制(zhi)中(zhong)的作用是(shi)人所共(gong)知的，在(zai)許多控制(zhi)過程中(zhong) 要(yao)求調(diao)(diao)節(jie)閥(fa)(fa)在(zai)故(gu)障時(shi)處于某一個位置(zhi)，以(yi)保護工藝(yi)過程不出(chu)現(xian)(xian)事(shi)故(gu)，這就(jiu)要(yao)求調(diao)(diao)節(jie)閥(fa)(fa)在(zai)設計(ji)上實(shi)現(xian)(xian)故(gu)障—安全的三(san) 斷(duan)(斷(duan)氣、斷(duan)電、斷(duan)信號)保護措施。對于電動調(diao)(diao)節(jie)閥(fa)(fa)來說，比較簡(jian)單，斷(duan)信號時(shi)，可以(yi)根據(ju)控制(zhi)模塊的設定而(er)停留(liu) 在(zai)全開、全關(guan)、保持中(zhong)的任一位置(zhi)，而(er)斷(duan)電時(shi)，自然停留(liu)在(zai)故(gu)障位置(zhi)，或帶(dai)有復位裝置(zhi)的電動執行(xing)器(qi)也可將(jiang)閥(fa)(fa)位運 行(xing)到全開或全關(guan)。
對于(yu)氣(qi)(qi)(qi)(qi)動(dong)調節閥來說，情況就比較復雜了(le)，所以(yi)我 們主要討論氣(qi)(qi)(qi)(qi)動(dong)調節閥的三(san)斷保(bao)位(wei)方法。一(yi)般(ban)來說，我們在選(xuan)擇(ze)氣(qi)(qi)(qi)(qi)動(dong)薄膜調節閥時(shi)，都要先確定選(xuan)氣(qi)(qi)(qi)(qi)開還是(shi)氣(qi)(qi)(qi)(qi)閉， 這就是(shi)選(xuan)擇(ze)調節閥斷氣(qi)(qi)(qi)(qi)時(shi)的保(bao)護(hu)(hu)位(wei)置，如果工藝要求斷氣(qi)(qi)(qi)(qi)時(shi)閥門打開，則選(xuan)擇(ze)常開(氣(qi)(qi)(qi)(qi)閉)式(shi)調節閥，反之(zhi)則選(xuan)常閉 (氣(qi)(qi)(qi)(qi)開)式(shi)調節閥。這只是(shi)一(yi)個粗淺的方案，如果工藝要求斷氣(qi)(qi)(qi)(qi)、斷電、斷信(xin)號的三(san)斷保(bao)護(hu)(hu)，則調節閥就需(xu)要配置一(yi) 些(xie)附件來組成(cheng)一(yi)個保(bao)護(hu)(hu)系統(tong)才能實現控制要求，這些(xie)附件主要有保(bao)位(wei)閥、電磁(ci)閥、氣(qi)(qi)(qi)(qi)罐等(deng)。以(yi)下是(shi)單作(zuo)用氣(qi)(qi)(qi)(qi)動(dong)薄膜 調節閥和(he)雙作(zuo)用氣(qi)(qi)(qi)(qi)動(dong)調節閥的兩種保(bao)位(wei)方案。
一、氣動(dong)薄(bo)膜(mo)調節(jie)閥(fa)方 案（調節(jie)閥(fa)配用電－氣閥(fa)門定位器）
本方案主要由氣(qi)(qi)動調節(jie)閥(fa)(fa)、電(dian)- 氣(qi)(qi)閥(fa)(fa)門定位(wei)器、失電(dian)(信號(hao))比較器、單電(dian)控電(dian)磁換向(xiang)閥(fa)(fa)、氣(qi)(qi)動保位(wei)閥(fa)(fa)、閥(fa)(fa)位(wei)信號(hao)返回器等組成。其工作原理如下：
1、斷氣(qi)源：當(dang)控(kong)制系(xi)統氣(qi)源故障(zhang)(失(shi)氣(qi))時(shi)，氣(qi)動保(bao)(bao)位閥(fa)(fa)自動關(guan)閉將(jiang) 定位器的輸出(chu)信(xin)號壓力鎖定在(zai)(zai)氣(qi)動控(kong)制閥(fa)(fa)的膜室內，輸出(chu)信(xin)號壓力與控(kong)制閥(fa)(fa)彈簧產(chan)生的反力相平(ping)衡，氣(qi)動控(kong)制閥(fa)(fa)的 閥(fa)(fa)位保(bao)(bao)持在(zai)(zai)故障(zhang)位置。該保(bao)(bao)位閥(fa)(fa)應設定在(zai)(zai)略低于氣(qi)源的最(zui)小值(zhi)時(shi)啟動。
2、斷(duan)電(dian)(dian)(dian)(dian)源(yuan)：當(dang)控(kong)(kong)制(zhi)系統電(dian)(dian)(dian)(dian)源(yuan)故(gu)障(zhang)(失(shi)(shi)電(dian)(dian)(dian)(dian))時，失(shi)(shi)電(dian)(dian)(dian)(dian)(信(xin)(xin)號)比較器控(kong)(kong)制(zhi) 單電(dian)(dian)(dian)(dian)控(kong)(kong)電(dian)(dian)(dian)(dian)磁換(huan)(huan)向(xiang)(xiang)閥(fa)(fa)(fa)的(de)(de)(de)輸出(chu)電(dian)(dian)(dian)(dian)壓(ya)消失(shi)(shi)，單電(dian)(dian)(dian)(dian)控(kong)(kong)電(dian)(dian)(dian)(dian)磁換(huan)(huan)向(xiang)(xiang)閥(fa)(fa)(fa)失(shi)(shi)電(dian)(dian)(dian)(dian)，單電(dian)(dian)(dian)(dian)控(kong)(kong)電(dian)(dian)(dian)(dian)磁換(huan)(huan)向(xiang)(xiang)閥(fa)(fa)(fa)內(nei)(nei)的(de)(de)(de)滑閥(fa)(fa)(fa)在(zai)復(fu)位(wei)(wei)彈簧的(de)(de)(de)作用(yong)下(xia)滑動(dong) ，電(dian)(dian)(dian)(dian)磁閥(fa)(fa)(fa)換(huan)(huan)向(xiang)(xiang)，將氣(qi)動(dong)保(bao)位(wei)(wei)閥(fa)(fa)(fa)的(de)(de)(de)膜(mo)室壓(ya)力排空，氣(qi)動(dong)保(bao)位(wei)(wei)閥(fa)(fa)(fa)關閉，將定(ding)位(wei)(wei)器的(de)(de)(de)輸出(chu)信(xin)(xin)號壓(ya)力鎖定(ding)在(zai)氣(qi)動(dong)控(kong)(kong)制(zhi)閥(fa)(fa)(fa)的(de)(de)(de)膜(mo) 室內(nei)(nei)，輸出(chu)信(xin)(xin)號壓(ya)力與控(kong)(kong)制(zhi)閥(fa)(fa)(fa)彈簧產生的(de)(de)(de)反力相平(ping)衡，氣(qi)動(dong)控(kong)(kong)制(zhi)閥(fa)(fa)(fa)的(de)(de)(de)閥(fa)(fa)(fa)位(wei)(wei)保(bao)持在(zai)故(gu)障(zhang)位(wei)(wei)置。
3、斷(duan)信(xin)號(hao)：當控(kong)(kong)制(zhi)系統(tong)信(xin)號(hao)故障(失信(xin)號(hao))時，失電(dian)(dian)(dian)(信(xin)號(hao))比較器(qi)檢(jian) 測到后，斷(duan)掉單(dan)電(dian)(dian)(dian)控(kong)(kong)電(dian)(dian)(dian)磁換(huan)向閥(fa)的(de)(de)電(dian)(dian)(dian)壓(ya)信(xin)號(hao)，單(dan)電(dian)(dian)(dian)控(kong)(kong)電(dian)(dian)(dian)磁換(huan)向閥(fa)失電(dian)(dian)(dian)，單(dan)電(dian)(dian)(dian)控(kong)(kong)電(dian)(dian)(dian)磁換(huan)向閥(fa)內(nei)的(de)(de)滑閥(fa)在(zai)復位(wei)(wei)彈簧(huang)的(de)(de)作 用下滑動(dong)，電(dian)(dian)(dian)磁閥(fa)換(huan)向，將氣(qi)動(dong)保(bao)位(wei)(wei)閥(fa)的(de)(de)膜室壓(ya)力排空，氣(qi)動(dong)保(bao)位(wei)(wei)閥(fa)關閉，將定位(wei)(wei)器(qi)的(de)(de)輸(shu)出信(xin)號(hao)壓(ya)力鎖定在(zai)氣(qi)動(dong)控(kong)(kong) 制(zhi)閥(fa)的(de)(de)膜室內(nei)，輸(shu)出信(xin)號(hao)壓(ya)力與(yu)控(kong)(kong)制(zhi)閥(fa)彈簧(huang)產生的(de)(de)反力相平衡，氣(qi)動(dong)控(kong)(kong)制(zhi)閥(fa)的(de)(de)閥(fa)位(wei)(wei)保(bao)持在(zai)故障位(wei)(wei)置。
