電(dian)磁(ci)(ci)閥(fa)(fa)（Electromagnetic valve）是(shi)用(yong)電(dian)磁(ci)(ci)控(kong)(kong)(kong)(kong)制的工業設備(bei)，是(shi)用(yong)來控(kong)(kong)(kong)(kong)制流(liu)體的自動(dong)化基(ji)礎(chu)元(yuan)件，屬于執(zhi)行器，并不(bu)(bu)限于液壓、氣(qi)動(dong)。用(yong)在工業控(kong)(kong)(kong)(kong)制系統中調(diao)(diao)整介(jie)質的方(fang)向、流(liu)量、速度(du)和其他的參數。電(dian)磁(ci)(ci)閥(fa)(fa)可(ke)以(yi)配合不(bu)(bu)同的電(dian)路來實現預期的控(kong)(kong)(kong)(kong)制，而控(kong)(kong)(kong)(kong)制的精度(du)和靈活性都能夠保證。電(dian)磁(ci)(ci)閥(fa)(fa)有很多種，不(bu)(bu)同的電(dian)磁(ci)(ci)閥(fa)(fa)在控(kong)(kong)(kong)(kong)制系統的不(bu)(bu)同位置發揮作用(yong)，最常用(yong)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(du)調(diao)(diao)節閥(fa)(fa)等。

電磁(ci)閥里有密閉的(de)(de)腔，在不(bu)同(tong)(tong)位置開有通(tong)(tong)孔(kong)，每個(ge)孔(kong)連接不(bu)同(tong)(tong)的(de)(de)油(you)管(guan)，腔中間是(shi)(shi)活(huo)塞，兩(liang)面(mian)是(shi)(shi)兩(liang)塊電磁(ci)鐵(tie)，哪面(mian)的(de)(de)磁(ci)鐵(tie)線圈通(tong)(tong)電閥體(ti)就會(hui)被吸引到哪邊，通(tong)(tong)過控(kong)制閥體(ti)的(de)(de)移動(dong)來開啟或(huo)關閉不(bu)同(tong)(tong)的(de)(de)排油(you)孔(kong)，而進油(you)孔(kong)是(shi)(shi)常開的(de)(de)，液壓油(you)就會(hui)進入不(bu)同(tong)(tong)的(de)(de)排油(you)管(guan)，然(ran)后通(tong)(tong)過油(you)的(de)(de)壓力來推(tui)動(dong)油(you)缸的(de)(de)活(huo)塞，活(huo)塞又帶(dai)動(dong)活(huo)塞桿，活(huo)塞桿帶(dai)動(dong)機械裝置。這樣(yang)通(tong)(tong)過控(kong)制電磁(ci)鐵(tie)的(de)(de)電流通(tong)(tong)斷就控(kong)制了機械運動(dong)。

1、電磁閥從原理上分為(wei)三大類：

直動式電磁(ci)閥

原理：通電(dian)時，電(dian)磁線(xian)圈產生電(dian)磁力(li)把關(guan)(guan)閉(bi)(bi)件從閥(fa)座上提起，閥(fa)門打開(kai)；斷電(dian)時，電(dian)磁力(li)消失，彈簧把關(guan)(guan)閉(bi)(bi)件壓(ya)在閥(fa)座上，閥(fa)門關(guan)(guan)閉(bi)(bi)。

特(te)點(dian)：在(zai)真空、負壓(ya)(ya)、零壓(ya)(ya)時能(neng)正常(chang)工作(zuo)，但通徑一般不超過(guo)25mm。

分(fen)步直動式電(dian)磁(ci)閥

原理：它是一(yi)種直(zhi)動(dong)和先導式相(xiang)結合的原理，當入(ru)(ru)口(kou)與(yu)出口(kou)沒有壓(ya)(ya)差時(shi)，通(tong)電后，電磁力直(zhi)接把先導小閥和主閥關閉件(jian)依次(ci)向(xiang)上提起，閥門打(da)開(kai)。當入(ru)(ru)口(kou)與(yu)出口(kou)達(da)到啟動(dong)壓(ya)(ya)差時(shi)，通(tong)電后，電磁力先導小閥，主閥下(xia)腔(qiang)壓(ya)(ya)力上升(sheng)，上腔(qiang)壓(ya)(ya)力下(xia)降，從而利用壓(ya)(ya)差把主閥向(xiang)上推開(kai)；斷電時(shi)，先導閥利用彈簧力或介質壓(ya)(ya)力推動(dong)關閉件(jian)，向(xiang)下(xia)移動(dong)，使閥門關閉。

特點(dian)：在零壓差或真空(kong)、高壓時亦能可*動作，但功率較大，要求必須水平安裝。

先導式電磁閥

原理：通(tong)電時(shi)，電磁力(li)把先導孔(kong)打開(kai)(kai)，上(shang)腔室(shi)壓力(li)迅(xun)速下(xia)降，在關(guan) 閉(bi)件(jian)周圍形(xing)成(cheng)上(shang)低下(xia)高的壓差，流體壓力(li)推動關(guan)閉(bi)件(jian)向(xiang)上(shang)移動，閥門打開(kai)(kai)；斷電時(shi)，彈簧力(li)把先導孔(kong)關(guan)閉(bi)，入口壓力(li)通(tong)過旁通(tong)孔(kong)迅(xun)速腔室(shi)在關(guan)閥件(jian)周圍形(xing)成(cheng)下(xia)低上(shang)高的壓差，流體壓力(li)推動關(guan)閉(bi)件(jian)向(xiang)下(xia)移動，關(guan)閉(bi)閥門。

特點：流(liu)體(ti)壓(ya)力范圍(wei)上限較高，可任意安(an)裝（需定(ding)制）但(dan)必(bi)須滿足(zu)流(liu)體(ti)壓(ya)差條件。

2、電磁閥(fa)從閥(fa)結(jie)(jie)(jie)構(gou)(gou)和材料上(shang)的不同(tong)與(yu)原理(li)上(shang)的區別，分(fen)為(wei)六(liu)個分(fen)支小類：直(zhi)動(dong)膜片(pian)(pian)結(jie)(jie)(jie)構(gou)(gou)、分(fen)步直(zhi)動(dong)膜片(pian)(pian)結(jie)(jie)(jie)構(gou)(gou)、先(xian)導(dao)膜片(pian)(pian)結(jie)(jie)(jie)構(gou)(gou)、直(zhi)動(dong)活(huo)(huo)塞(sai)結(jie)(jie)(jie)構(gou)(gou)、分(fen)步直(zhi)動(dong)活(huo)(huo)塞(sai)結(jie)(jie)(jie)構(gou)(gou)、先(xian)導(dao)活(huo)(huo)塞(sai)結(jie)(jie)(jie)構(gou)(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)按照功能分(fen)類：水用(yong)電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、消防電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、氨(an)用(yong)電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、液體電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、脈(mo)沖電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、液壓電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa) 常開(kai)電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、油用(yong)電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)、防爆(bao)電(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)(fa)等。