電磁(ci)閥（Electromagnetic valve）是(shi)(shi)用(yong)(yong)(yong)電磁(ci)控制的(de)工業設(she)備，是(shi)(shi)用(yong)(yong)(yong)來(lai)控制流體的(de)自(zi)動化基礎元件，屬于(yu)(yu)執行器(qi)，并不(bu)限于(yu)(yu)液壓、氣動。用(yong)(yong)(yong)在工業控制系(xi)(xi)統(tong)中調整介質的(de)方(fang)向(xiang)、流量、速度和(he)其他的(de)參(can)數。電磁(ci)閥可以配合不(bu)同(tong)的(de)電路來(lai)實現預期(qi)的(de)控制，而控制的(de)精度和(he)靈活(huo)性都(dou)能夠(gou)保證。電磁(ci)閥有很多(duo)種，不(bu)同(tong)的(de)電磁(ci)閥在控制系(xi)(xi)統(tong)的(de)不(bu)同(tong)位(wei)置發揮(hui)作用(yong)(yong)(yong)，最常用(yong)(yong)(yong)的(de)是(shi)(shi)單向(xiang)閥、安全閥、方(fang)向(xiang)控制閥、速度調節閥等。

電(dian)磁(ci)(ci)(ci)閥(fa)里有密閉(bi)的(de)(de)腔，在不同(tong)位(wei)置開有通(tong)(tong)(tong)(tong)孔(kong)，每個(ge)孔(kong)連接不同(tong)的(de)(de)油(you)管，腔中間是(shi)活(huo)(huo)塞，兩(liang)面是(shi)兩(liang)塊(kuai)電(dian)磁(ci)(ci)(ci)鐵，哪面的(de)(de)磁(ci)(ci)(ci)鐵線圈通(tong)(tong)(tong)(tong)電(dian)閥(fa)體(ti)就(jiu)會被吸引到哪邊，通(tong)(tong)(tong)(tong)過(guo)控(kong)制(zhi)閥(fa)體(ti)的(de)(de)移動(dong)來(lai)(lai)開啟或關閉(bi)不同(tong)的(de)(de)排(pai)油(you)孔(kong)，而進(jin)油(you)孔(kong)是(shi)常開的(de)(de)，液壓(ya)油(you)就(jiu)會進(jin)入(ru)不同(tong)的(de)(de)排(pai)油(you)管，然后通(tong)(tong)(tong)(tong)過(guo)油(you)的(de)(de)壓(ya)力來(lai)(lai)推動(dong)油(you)缸的(de)(de)活(huo)(huo)塞，活(huo)(huo)塞又帶(dai)動(dong)活(huo)(huo)塞桿(gan)，活(huo)(huo)塞桿(gan)帶(dai)動(dong)機械(xie)裝置。這樣通(tong)(tong)(tong)(tong)過(guo)控(kong)制(zhi)電(dian)磁(ci)(ci)(ci)鐵的(de)(de)電(dian)流通(tong)(tong)(tong)(tong)斷就(jiu)控(kong)制(zhi)了機械(xie)運(yun)動(dong)。

1、電磁閥從原理上分為(wei)三大類：

直動式電磁閥

原理：通電時，電磁線圈產生電磁力把關(guan)閉件從閥(fa)座(zuo)上提起，閥(fa)門(men)打開；斷電時，電磁力消(xiao)失，彈簧把關(guan)閉件壓在閥(fa)座(zuo)上，閥(fa)門(men)關(guan)閉。

特點：在真空、負壓、零壓時能正常工作，但通徑一般不(bu)超過25mm。

分步直動式(shi)電磁閥

原理：它是一(yi)種直動和先導(dao)式相結(jie)合的原理，當入(ru)口(kou)與出口(kou)沒(mei)有壓(ya)差時，通(tong)電(dian)(dian)后(hou)，電(dian)(dian)磁(ci)力(li)直接把先導(dao)小閥(fa)(fa)(fa)(fa)和主(zhu)閥(fa)(fa)(fa)(fa)關(guan)閉(bi)件依(yi)次(ci)向上(shang)提起，閥(fa)(fa)(fa)(fa)門打開(kai)(kai)。當入(ru)口(kou)與出口(kou)達(da)到啟(qi)動壓(ya)差時，通(tong)電(dian)(dian)后(hou)，電(dian)(dian)磁(ci)力(li)先導(dao)小閥(fa)(fa)(fa)(fa)，主(zhu)閥(fa)(fa)(fa)(fa)下腔(qiang)壓(ya)力(li)上(shang)升，上(shang)腔(qiang)壓(ya)力(li)下降，從而利用壓(ya)差把主(zhu)閥(fa)(fa)(fa)(fa)向上(shang)推(tui)開(kai)(kai)；斷電(dian)(dian)時，先導(dao)閥(fa)(fa)(fa)(fa)利用彈(dan)簧力(li)或介質壓(ya)力(li)推(tui)動關(guan)閉(bi)件，向下移動，使閥(fa)(fa)(fa)(fa)門關(guan)閉(bi)。

特點：在零壓差或(huo)真(zhen)空、高(gao)壓時亦能可*動作，但(dan)功率(lv)較大(da)，要求必須水平安裝(zhuang)。

先導式電磁閥

原理：通(tong)電時(shi)，電磁力把先導孔(kong)打開(kai)，上(shang)腔室壓力迅速(su)下(xia)降，在關(guan)(guan)(guan) 閉件周圍形成上(shang)低下(xia)高(gao)(gao)的壓差(cha)，流體(ti)壓力推(tui)動(dong)關(guan)(guan)(guan)閉件向上(shang)移動(dong)，閥(fa)門打開(kai)；斷電時(shi)，彈簧(huang)力把先導孔(kong)關(guan)(guan)(guan)閉，入(ru)口(kou)壓力通(tong)過旁(pang)通(tong)孔(kong)迅速(su)腔室在關(guan)(guan)(guan)閥(fa)件周圍形成下(xia)低上(shang)高(gao)(gao)的壓差(cha)，流體(ti)壓力推(tui)動(dong)關(guan)(guan)(guan)閉件向下(xia)移動(dong)，關(guan)(guan)(guan)閉閥(fa)門。

特點(dian)：流(liu)體壓力范(fan)圍上(shang)限較高，可任意安裝（需定制）但(dan)必須(xu)滿(man)足流(liu)體壓差條件。

2、電磁閥從(cong)閥結(jie)構和材料上(shang)的(de)不同與原(yuan)理上(shang)的(de)區別，分(fen)為六個(ge)分(fen)支小類：直(zhi)(zhi)(zhi)動(dong)(dong)膜(mo)片結(jie)構、分(fen)步直(zhi)(zhi)(zhi)動(dong)(dong)膜(mo)片結(jie)構、先導膜(mo)片結(jie)構、直(zhi)(zhi)(zhi)動(dong)(dong)活(huo)塞(sai)結(jie)構、分(fen)步直(zhi)(zhi)(zhi)動(dong)(dong)活(huo)塞(sai)結(jie)構、先導活(huo)塞(sai)結(jie)構。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)按照(zhao)功(gong)能分類：水用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、制(zhi)冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、低溫(wen)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、氨(an)用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、液體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、液壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa) 常開(kai)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、油用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、直(zhi)流電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、防(fang)爆電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)等。