電(dian)磁閥(fa)（Electromagnetic valve）是用(yong)(yong)電(dian)磁控(kong)(kong)制(zhi)(zhi)(zhi)(zhi)的(de)(de)(de)工(gong)業設備，是用(yong)(yong)來控(kong)(kong)制(zhi)(zhi)(zhi)(zhi)流體的(de)(de)(de)自動(dong)化基礎元件，屬于(yu)執行(xing)器，并不(bu)(bu)(bu)限于(yu)液壓(ya)、氣動(dong)。用(yong)(yong)在工(gong)業控(kong)(kong)制(zhi)(zhi)(zhi)(zhi)系(xi)統中調整介質的(de)(de)(de)方向(xiang)(xiang)、流量、速(su)度(du)和其(qi)他的(de)(de)(de)參數。電(dian)磁閥(fa)可(ke)以配(pei)合(he)不(bu)(bu)(bu)同的(de)(de)(de)電(dian)路來實(shi)現預(yu)期(qi)的(de)(de)(de)控(kong)(kong)制(zhi)(zhi)(zhi)(zhi)，而控(kong)(kong)制(zhi)(zhi)(zhi)(zhi)的(de)(de)(de)精度(du)和靈活性都能夠(gou)保證。電(dian)磁閥(fa)有很(hen)多種，不(bu)(bu)(bu)同的(de)(de)(de)電(dian)磁閥(fa)在控(kong)(kong)制(zhi)(zhi)(zhi)(zhi)系(xi)統的(de)(de)(de)不(bu)(bu)(bu)同位置發(fa)揮作用(yong)(yong)，最常用(yong)(yong)的(de)(de)(de)是單向(xiang)(xiang)閥(fa)、安全閥(fa)、方向(xiang)(xiang)控(kong)(kong)制(zhi)(zhi)(zhi)(zhi)閥(fa)、速(su)度(du)調節閥(fa)等。

電磁閥(fa)里(li)有密閉的(de)腔(qiang)，在不同(tong)(tong)位置(zhi)開有通(tong)孔(kong)，每個孔(kong)連(lian)接不同(tong)(tong)的(de)油管，腔(qiang)中間(jian)是(shi)活塞，兩(liang)面(mian)是(shi)兩(liang)塊電磁鐵，哪(na)面(mian)的(de)磁鐵線圈通(tong)電閥(fa)體就(jiu)會(hui)被吸引到(dao)哪(na)邊，通(tong)過控制(zhi)閥(fa)體的(de)移動來(lai)開啟或關閉不同(tong)(tong)的(de)排油孔(kong)，而進油孔(kong)是(shi)常開的(de)，液壓油就(jiu)會(hui)進入不同(tong)(tong)的(de)排油管，然后通(tong)過油的(de)壓力(li)來(lai)推動油缸的(de)活塞，活塞又(you)帶動活塞桿，活塞桿帶動機械裝置(zhi)。這樣通(tong)過控制(zhi)電磁鐵的(de)電流通(tong)斷(duan)就(jiu)控制(zhi)了機械運動。

1、電磁閥從原(yuan)理(li)上分為三大(da)類：

直(zhi)動式電磁閥

原理：通電(dian)(dian)時(shi)，電(dian)(dian)磁(ci)線圈產生電(dian)(dian)磁(ci)力(li)把(ba)關(guan)閉(bi)(bi)件從閥(fa)座(zuo)上提起，閥(fa)門(men)打開；斷電(dian)(dian)時(shi)，電(dian)(dian)磁(ci)力(li)消失，彈簧把(ba)關(guan)閉(bi)(bi)件壓在閥(fa)座(zuo)上，閥(fa)門(men)關(guan)閉(bi)(bi)。

特點：在真(zhen)空、負壓(ya)、零壓(ya)時能(neng)正常工作(zuo)，但通徑一般不超過25mm。

分步直動式電磁閥

原(yuan)理：它是一種直(zhi)動和先導(dao)式相結合的原(yuan)理，當(dang)入口與(yu)(yu)出口沒有壓(ya)(ya)(ya)差時(shi)，通(tong)電(dian)后，電(dian)磁力(li)(li)直(zhi)接把先導(dao)小(xiao)閥(fa)(fa)和主閥(fa)(fa)關閉(bi)件(jian)依(yi)次向(xiang)(xiang)上(shang)提(ti)起(qi)，閥(fa)(fa)門打開。當(dang)入口與(yu)(yu)出口達到(dao)啟動壓(ya)(ya)(ya)差時(shi)，通(tong)電(dian)后，電(dian)磁力(li)(li)先導(dao)小(xiao)閥(fa)(fa)，主閥(fa)(fa)下腔壓(ya)(ya)(ya)力(li)(li)上(shang)升，上(shang)腔壓(ya)(ya)(ya)力(li)(li)下降，從而利(li)用壓(ya)(ya)(ya)差把主閥(fa)(fa)向(xiang)(xiang)上(shang)推(tui)開；斷電(dian)時(shi)，先導(dao)閥(fa)(fa)利(li)用彈簧力(li)(li)或介質壓(ya)(ya)(ya)力(li)(li)推(tui)動關閉(bi)件(jian)，向(xiang)(xiang)下移動，使(shi)閥(fa)(fa)門關閉(bi)。

特點：在零(ling)壓差或真空、高(gao)壓時亦能(neng)可(ke)*動(dong)作，但(dan)功率較大，要求必須水平安裝(zhuang)。

先導(dao)式電(dian)磁閥(fa)

原(yuan)理：通電(dian)(dian)時(shi)(shi)，電(dian)(dian)磁(ci)力(li)(li)把先導(dao)孔打(da)開(kai)，上腔室壓(ya)(ya)力(li)(li)迅(xun)速(su)下(xia)(xia)降，在(zai)關 閉(bi)(bi)(bi)件(jian)周圍(wei)形成上低下(xia)(xia)高的(de)壓(ya)(ya)差(cha)(cha)，流體壓(ya)(ya)力(li)(li)推動(dong)(dong)關閉(bi)(bi)(bi)件(jian)向上移動(dong)(dong)，閥(fa)門(men)打(da)開(kai)；斷(duan)電(dian)(dian)時(shi)(shi)，彈簧力(li)(li)把先導(dao)孔關閉(bi)(bi)(bi)，入(ru)口(kou)壓(ya)(ya)力(li)(li)通過旁通孔迅(xun)速(su)腔室在(zai)關閥(fa)件(jian)周圍(wei)形成下(xia)(xia)低上高的(de)壓(ya)(ya)差(cha)(cha)，流體壓(ya)(ya)力(li)(li)推動(dong)(dong)關閉(bi)(bi)(bi)件(jian)向下(xia)(xia)移動(dong)(dong)，關閉(bi)(bi)(bi)閥(fa)門(men)。

特點：流體壓力范圍上限(xian)較高，可任意(yi)安裝（需(xu)定制）但必(bi)須滿足(zu)流體壓差條件。

2、電磁閥(fa)從閥(fa)結(jie)構(gou)和材料上的(de)不同(tong)與(yu)原理上的(de)區別，分(fen)(fen)(fen)為六個分(fen)(fen)(fen)支小類：直(zhi)動膜(mo)片(pian)結(jie)構(gou)、分(fen)(fen)(fen)步(bu)直(zhi)動膜(mo)片(pian)結(jie)構(gou)、先導膜(mo)片(pian)結(jie)構(gou)、直(zhi)動活(huo)(huo)塞(sai)結(jie)構(gou)、分(fen)(fen)(fen)步(bu)直(zhi)動活(huo)(huo)塞(sai)結(jie)構(gou)、先導活(huo)(huo)塞(sai)結(jie)構(gou)。

3、電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)按照功能分類：水用電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、制(zhi)冷電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、消(xiao)防(fang)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、氨用電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、氣(qi)體(ti)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、液(ye)體(ti)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、微型(xing)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、液(ye)壓電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、油用電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、直(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、防(fang)爆電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)等。