電(dian)(dian)(dian)磁閥(fa)(fa)（Electromagnetic valve）是用(yong)電(dian)(dian)(dian)磁控制的(de)工(gong)業(ye)設(she)備(bei)，是用(yong)來控制流(liu)體的(de)自動(dong)化基礎元件(jian)，屬于執行器，并不(bu)限于液壓、氣動(dong)。用(yong)在工(gong)業(ye)控制系(xi)統中調(diao)整介質的(de)方向(xiang)、流(liu)量、速度和(he)其(qi)他的(de)參(can)數。電(dian)(dian)(dian)磁閥(fa)(fa)可以配合不(bu)同的(de)電(dian)(dian)(dian)路來實現預期的(de)控制，而控制的(de)精度和(he)靈(ling)活性都能夠(gou)保證。電(dian)(dian)(dian)磁閥(fa)(fa)有很多(duo)種，不(bu)同的(de)電(dian)(dian)(dian)磁閥(fa)(fa)在控制系(xi)統的(de)不(bu)同位置發(fa)揮(hui)作用(yong)，最常用(yong)的(de)是單(dan)向(xiang)閥(fa)(fa)、安全閥(fa)(fa)、方向(xiang)控制閥(fa)(fa)、速度調(diao)節閥(fa)(fa)等。

電(dian)磁閥里有密閉(bi)的(de)(de)(de)腔(qiang)，在不同位置(zhi)開有通(tong)(tong)(tong)孔，每個孔連接不同的(de)(de)(de)油(you)(you)(you)管(guan)，腔(qiang)中間(jian)是活(huo)塞(sai)，兩面是兩塊電(dian)磁鐵，哪面的(de)(de)(de)磁鐵線圈通(tong)(tong)(tong)電(dian)閥體就會被吸(xi)引到(dao)哪邊，通(tong)(tong)(tong)過控(kong)制閥體的(de)(de)(de)移動(dong)來開啟或關(guan)閉(bi)不同的(de)(de)(de)排油(you)(you)(you)孔，而進油(you)(you)(you)孔是常開的(de)(de)(de)，液(ye)壓油(you)(you)(you)就會進入(ru)不同的(de)(de)(de)排油(you)(you)(you)管(guan)，然后通(tong)(tong)(tong)過油(you)(you)(you)的(de)(de)(de)壓力來推動(dong)油(you)(you)(you)缸的(de)(de)(de)活(huo)塞(sai)，活(huo)塞(sai)又帶(dai)動(dong)活(huo)塞(sai)桿，活(huo)塞(sai)桿帶(dai)動(dong)機械裝置(zhi)。這樣通(tong)(tong)(tong)過控(kong)制電(dian)磁鐵的(de)(de)(de)電(dian)流通(tong)(tong)(tong)斷(duan)就控(kong)制了機械運(yun)動(dong)。

1、電(dian)磁閥從原理上分為三大類：

直動式(shi)電磁閥

原理：通(tong)電(dian)時(shi)，電(dian)磁(ci)線(xian)圈產生電(dian)磁(ci)力把(ba)關(guan)閉件從閥(fa)(fa)座上(shang)提起，閥(fa)(fa)門(men)打(da)開(kai)；斷電(dian)時(shi)，電(dian)磁(ci)力消(xiao)失(shi)，彈簧把(ba)關(guan)閉件壓在(zai)閥(fa)(fa)座上(shang)，閥(fa)(fa)門(men)關(guan)閉。

特點：在真空、負壓(ya)、零(ling)壓(ya)時(shi)能正常工(gong)作，但通徑一般不(bu)超過25mm。

分步直動式電磁(ci)閥

原理：它是一種(zhong)直動(dong)和先(xian)導(dao)(dao)式相結合的原理，當(dang)(dang)入口(kou)(kou)與(yu)(yu)出口(kou)(kou)沒有壓(ya)(ya)差(cha)(cha)(cha)時，通電后(hou)，電磁力直接把(ba)先(xian)導(dao)(dao)小(xiao)閥(fa)和主(zhu)閥(fa)關(guan)閉件依次向上提起，閥(fa)門打開(kai)。當(dang)(dang)入口(kou)(kou)與(yu)(yu)出口(kou)(kou)達到啟動(dong)壓(ya)(ya)差(cha)(cha)(cha)時，通電后(hou)，電磁力先(xian)導(dao)(dao)小(xiao)閥(fa)，主(zhu)閥(fa)下(xia)(xia)腔(qiang)壓(ya)(ya)力上升，上腔(qiang)壓(ya)(ya)力下(xia)(xia)降，從而利用(yong)(yong)壓(ya)(ya)差(cha)(cha)(cha)把(ba)主(zhu)閥(fa)向上推(tui)開(kai)；斷電時，先(xian)導(dao)(dao)閥(fa)利用(yong)(yong)彈簧力或介質壓(ya)(ya)力推(tui)動(dong)關(guan)閉件，向下(xia)(xia)移(yi)動(dong)，使閥(fa)門關(guan)閉。

特點(dian)：在(zai)零壓差或真空、高壓時亦能可*動作(zuo)，但(dan)功(gong)率較大，要求必須水(shui)平安(an)裝。

先導式電(dian)磁閥

原理(li)：通(tong)電(dian)時，電(dian)磁力把先(xian)導孔(kong)(kong)(kong)打(da)開，上(shang)腔室壓(ya)(ya)力迅速下降(jiang)，在(zai)關 閉(bi)(bi)件(jian)(jian)周(zhou)(zhou)圍形成上(shang)低(di)(di)下高(gao)的壓(ya)(ya)差(cha)，流體壓(ya)(ya)力推動(dong)關閉(bi)(bi)件(jian)(jian)向上(shang)移動(dong)，閥門(men)打(da)開；斷電(dian)時，彈簧力把先(xian)導孔(kong)(kong)(kong)關閉(bi)(bi)，入口壓(ya)(ya)力通(tong)過(guo)旁(pang)通(tong)孔(kong)(kong)(kong)迅速腔室在(zai)關閥件(jian)(jian)周(zhou)(zhou)圍形成下低(di)(di)上(shang)高(gao)的壓(ya)(ya)差(cha)，流體壓(ya)(ya)力推動(dong)關閉(bi)(bi)件(jian)(jian)向下移動(dong)，關閉(bi)(bi)閥門(men)。

特點(dian)：流體(ti)(ti)壓(ya)力(li)范(fan)圍上限較高(gao)，可(ke)任意安裝（需定制）但必須滿足流體(ti)(ti)壓(ya)差(cha)條件。

2、電磁閥從閥結(jie)構(gou)(gou)和材料上的不同與(yu)原理上的區別，分(fen)為六個(ge)分(fen)支(zhi)小類：直動膜(mo)片(pian)結(jie)構(gou)(gou)、分(fen)步直動膜(mo)片(pian)結(jie)構(gou)(gou)、先(xian)導膜(mo)片(pian)結(jie)構(gou)(gou)、直動活塞(sai)結(jie)構(gou)(gou)、分(fen)步直動活塞(sai)結(jie)構(gou)(gou)、先(xian)導活塞(sai)結(jie)構(gou)(gou)。

3、電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)按照功能(neng)分類：水用(yong)電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、制冷電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、消防電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、氨用(yong)電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、氣(qi)體(ti)電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、液體(ti)電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、微型電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、脈沖(chong)電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、液壓(ya)電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa) 常開電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、油用(yong)電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、直(zhi)流電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、高(gao)壓(ya)電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、防爆電(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)等。