電(dian)磁(ci)閥(fa)(fa)（Electromagnetic valve）是(shi)用電(dian)磁(ci)控(kong)(kong)(kong)(kong)制的工業設備，是(shi)用來控(kong)(kong)(kong)(kong)制流(liu)體(ti)的自動化基(ji)礎元件，屬于執(zhi)行器，并不(bu)(bu)限(xian)于液壓(ya)、氣動。用在工業控(kong)(kong)(kong)(kong)制系統中調(diao)整介(jie)質的方(fang)向、流(liu)量、速度和其他(ta)的參數。電(dian)磁(ci)閥(fa)(fa)可以(yi)配(pei)合不(bu)(bu)同(tong)的電(dian)路來實(shi)現預期的控(kong)(kong)(kong)(kong)制，而控(kong)(kong)(kong)(kong)制的精(jing)度和靈活性都能夠保證。電(dian)磁(ci)閥(fa)(fa)有很多種，不(bu)(bu)同(tong)的電(dian)磁(ci)閥(fa)(fa)在控(kong)(kong)(kong)(kong)制系統的不(bu)(bu)同(tong)位(wei)置發揮作(zuo)用，最常用的是(shi)單向閥(fa)(fa)、安全閥(fa)(fa)、方(fang)向控(kong)(kong)(kong)(kong)制閥(fa)(fa)、速度調(diao)節閥(fa)(fa)等。

電磁閥(fa)里有(you)密(mi)閉的(de)腔，在不(bu)同(tong)位置開(kai)有(you)通(tong)(tong)孔(kong)(kong)，每個孔(kong)(kong)連(lian)接不(bu)同(tong)的(de)油(you)管(guan)，腔中間(jian)是(shi)活(huo)塞，兩面是(shi)兩塊電磁鐵(tie)，哪面的(de)磁鐵(tie)線圈通(tong)(tong)電閥(fa)體就會被吸(xi)引到哪邊，通(tong)(tong)過(guo)控(kong)(kong)制(zhi)閥(fa)體的(de)移動來開(kai)啟或關閉不(bu)同(tong)的(de)排(pai)油(you)孔(kong)(kong)，而進油(you)孔(kong)(kong)是(shi)常(chang)開(kai)的(de)，液壓油(you)就會進入(ru)不(bu)同(tong)的(de)排(pai)油(you)管(guan)，然(ran)后通(tong)(tong)過(guo)油(you)的(de)壓力來推動油(you)缸(gang)的(de)活(huo)塞，活(huo)塞又帶(dai)動活(huo)塞桿(gan)(gan)，活(huo)塞桿(gan)(gan)帶(dai)動機械(xie)裝置。這樣(yang)通(tong)(tong)過(guo)控(kong)(kong)制(zhi)電磁鐵(tie)的(de)電流通(tong)(tong)斷(duan)就控(kong)(kong)制(zhi)了機械(xie)運動。

1、電磁閥從原理上分為三(san)大類：

直動式(shi)電(dian)磁(ci)閥

原理：通電時，電磁線圈產生電磁力把關(guan)閉件從閥(fa)座上(shang)提(ti)起，閥(fa)門打開(kai)；斷電時，電磁力消失，彈簧把關(guan)閉件壓在(zai)閥(fa)座上(shang)，閥(fa)門關(guan)閉。

特點：在(zai)真空、負壓、零(ling)壓時(shi)能(neng)正(zheng)常工作，但通徑一(yi)般不超過25mm。

分步直動式電磁閥

原理：它是一(yi)種直動和先導(dao)式(shi)相結(jie)合(he)的原理，當入(ru)口與出(chu)口沒有壓(ya)差時(shi)，通電(dian)(dian)后(hou)，電(dian)(dian)磁力(li)直接(jie)把(ba)先導(dao)小(xiao)閥(fa)(fa)和主閥(fa)(fa)關(guan)閉(bi)件依次向上(shang)(shang)提起，閥(fa)(fa)門(men)打開。當入(ru)口與出(chu)口達(da)到啟(qi)動壓(ya)差時(shi)，通電(dian)(dian)后(hou)，電(dian)(dian)磁力(li)先導(dao)小(xiao)閥(fa)(fa)，主閥(fa)(fa)下(xia)腔(qiang)壓(ya)力(li)上(shang)(shang)升，上(shang)(shang)腔(qiang)壓(ya)力(li)下(xia)降，從而利(li)用(yong)壓(ya)差把(ba)主閥(fa)(fa)向上(shang)(shang)推開；斷電(dian)(dian)時(shi)，先導(dao)閥(fa)(fa)利(li)用(yong)彈簧力(li)或介(jie)質壓(ya)力(li)推動關(guan)閉(bi)件，向下(xia)移動，使閥(fa)(fa)門(men)關(guan)閉(bi)。

特點：在零壓(ya)(ya)差或(huo)真空(kong)、高壓(ya)(ya)時亦能(neng)可*動作，但功率較大，要(yao)求(qiu)必須水平安裝。

先導式電磁閥

原理：通電時，電磁力把(ba)先導孔(kong)打(da)開(kai)，上腔(qiang)室壓力迅(xun)速(su)下降，在(zai)關 閉(bi)件(jian)周圍(wei)形成上低(di)下高的壓差，流體壓力推動(dong)關閉(bi)件(jian)向(xiang)上移(yi)動(dong)，閥門(men)打(da)開(kai)；斷(duan)電時，彈簧力把(ba)先導孔(kong)關閉(bi)，入口壓力通過旁通孔(kong)迅(xun)速(su)腔(qiang)室在(zai)關閥件(jian)周圍(wei)形成下低(di)上高的壓差，流體壓力推動(dong)關閉(bi)件(jian)向(xiang)下移(yi)動(dong)，關閉(bi)閥門(men)。

特點：流體壓(ya)(ya)力(li)范圍上限(xian)較(jiao)高，可任意安裝（需定制(zhi)）但必須滿足流體壓(ya)(ya)差條件。

2、電磁(ci)閥從閥結(jie)(jie)(jie)(jie)構(gou)和材料上的不同與原理上的區別，分為(wei)六個分支小類：直(zhi)動膜片結(jie)(jie)(jie)(jie)構(gou)、分步直(zhi)動膜片結(jie)(jie)(jie)(jie)構(gou)、先導(dao)膜片結(jie)(jie)(jie)(jie)構(gou)、直(zhi)動活塞(sai)結(jie)(jie)(jie)(jie)構(gou)、分步直(zhi)動活塞(sai)結(jie)(jie)(jie)(jie)構(gou)、先導(dao)活塞(sai)結(jie)(jie)(jie)(jie)構(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)按照(zhao)功能分類：水用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、制(zhi)冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、低溫(wen)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、消防(fang)(fang)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、氨用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、液(ye)體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、微(wei)型電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、脈(mo)沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、液(ye)壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、油(you)用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、防(fang)(fang)爆(bao)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)等。