電(dian)磁閥(fa)（Electromagnetic valve）是用(yong)電(dian)磁控(kong)制(zhi)(zhi)的工(gong)業設備，是用(yong)來控(kong)制(zhi)(zhi)流體(ti)的自動化基礎元件，屬于(yu)執行器，并不(bu)(bu)(bu)限于(yu)液壓、氣動。用(yong)在工(gong)業控(kong)制(zhi)(zhi)系統中調整介質(zhi)的方向(xiang)、流量、速度(du)和其他的參(can)數。電(dian)磁閥(fa)可以配合(he)不(bu)(bu)(bu)同的電(dian)路來實現預期的控(kong)制(zhi)(zhi)，而控(kong)制(zhi)(zhi)的精度(du)和靈活性(xing)都能夠保證。電(dian)磁閥(fa)有很(hen)多(duo)種，不(bu)(bu)(bu)同的電(dian)磁閥(fa)在控(kong)制(zhi)(zhi)系統的不(bu)(bu)(bu)同位置(zhi)發揮作用(yong)，最常用(yong)的是單向(xiang)閥(fa)、安全閥(fa)、方向(xiang)控(kong)制(zhi)(zhi)閥(fa)、速度(du)調節閥(fa)等(deng)。

電(dian)磁閥里有(you)密閉(bi)的(de)(de)腔，在不(bu)同(tong)(tong)位置開有(you)通(tong)孔(kong)，每個孔(kong)連接不(bu)同(tong)(tong)的(de)(de)油(you)管，腔中間(jian)是(shi)(shi)活塞(sai)，兩(liang)面(mian)是(shi)(shi)兩(liang)塊電(dian)磁鐵，哪面(mian)的(de)(de)磁鐵線(xian)圈(quan)通(tong)電(dian)閥體(ti)就(jiu)(jiu)會被吸引到哪邊，通(tong)過控制(zhi)閥體(ti)的(de)(de)移(yi)動(dong)(dong)來開啟(qi)或關閉(bi)不(bu)同(tong)(tong)的(de)(de)排(pai)油(you)孔(kong)，而進油(you)孔(kong)是(shi)(shi)常開的(de)(de)，液壓油(you)就(jiu)(jiu)會進入不(bu)同(tong)(tong)的(de)(de)排(pai)油(you)管，然后通(tong)過油(you)的(de)(de)壓力來推動(dong)(dong)油(you)缸的(de)(de)活塞(sai)，活塞(sai)又帶動(dong)(dong)活塞(sai)桿(gan)，活塞(sai)桿(gan)帶動(dong)(dong)機(ji)械裝置。這樣通(tong)過控制(zhi)電(dian)磁鐵的(de)(de)電(dian)流通(tong)斷就(jiu)(jiu)控制(zhi)了(le)機(ji)械運動(dong)(dong)。

1、電磁(ci)閥從原理上分為三(san)大(da)類：

直動(dong)式電磁閥

原理：通(tong)電時，電磁線圈產(chan)生電磁力(li)把(ba)(ba)關閉件從(cong)閥(fa)座上(shang)提起，閥(fa)門打開；斷電時，電磁力(li)消(xiao)失，彈簧把(ba)(ba)關閉件壓在閥(fa)座上(shang)，閥(fa)門關閉。

特點：在真空、負壓(ya)、零壓(ya)時(shi)能正常工作，但(dan)通徑(jing)一般不超過25mm。

分(fen)步直動(dong)式(shi)電磁閥

原理：它是一種直動和先(xian)導式相結合的原理，當入口(kou)與出(chu)(chu)口(kou)沒(mei)有(you)壓差(cha)(cha)時(shi)，通(tong)(tong)電(dian)(dian)后(hou)，電(dian)(dian)磁力直接把先(xian)導小閥(fa)(fa)和主閥(fa)(fa)關閉(bi)件(jian)依次向上提(ti)起，閥(fa)(fa)門打(da)開(kai)。當入口(kou)與出(chu)(chu)口(kou)達到啟動壓差(cha)(cha)時(shi)，通(tong)(tong)電(dian)(dian)后(hou)，電(dian)(dian)磁力先(xian)導小閥(fa)(fa)，主閥(fa)(fa)下腔壓力上升，上腔壓力下降，從(cong)而(er)利用壓差(cha)(cha)把主閥(fa)(fa)向上推(tui)開(kai)；斷(duan)電(dian)(dian)時(shi)，先(xian)導閥(fa)(fa)利用彈簧力或介質壓力推(tui)動關閉(bi)件(jian)，向下移動，使(shi)閥(fa)(fa)門關閉(bi)。

特點：在零壓差或真空(kong)、高壓時亦能可*動作，但(dan)功率較大，要(yao)求必須水平安(an)裝。

先導式電磁(ci)閥

原理：通(tong)電(dian)時，電(dian)磁(ci)力(li)(li)(li)把先(xian)導孔(kong)打開，上(shang)腔室(shi)壓力(li)(li)(li)迅速(su)下(xia)(xia)降，在關(guan) 閉件周圍(wei)形(xing)(xing)成(cheng)上(shang)低下(xia)(xia)高的壓差(cha)，流體壓力(li)(li)(li)推動(dong)關(guan)閉件向(xiang)上(shang)移(yi)動(dong)，閥(fa)門打開；斷電(dian)時，彈簧力(li)(li)(li)把先(xian)導孔(kong)關(guan)閉，入口壓力(li)(li)(li)通(tong)過旁通(tong)孔(kong)迅速(su)腔室(shi)在關(guan)閥(fa)件周圍(wei)形(xing)(xing)成(cheng)下(xia)(xia)低上(shang)高的壓差(cha)，流體壓力(li)(li)(li)推動(dong)關(guan)閉件向(xiang)下(xia)(xia)移(yi)動(dong)，關(guan)閉閥(fa)門。

特點(dian)：流體(ti)壓力范(fan)圍上限較高(gao)，可(ke)任意安(an)裝(zhuang)（需定制(zhi)）但(dan)必須滿足流體(ti)壓差(cha)條件。

2、電磁閥從閥結(jie)構(gou)(gou)和材料上(shang)的不同(tong)與原理(li)上(shang)的區(qu)別(bie)，分(fen)為六個分(fen)支小類：直(zhi)(zhi)動膜(mo)片結(jie)構(gou)(gou)、分(fen)步直(zhi)(zhi)動膜(mo)片結(jie)構(gou)(gou)、先導膜(mo)片結(jie)構(gou)(gou)、直(zhi)(zhi)動活塞(sai)結(jie)構(gou)(gou)、分(fen)步直(zhi)(zhi)動活塞(sai)結(jie)構(gou)(gou)、先導活塞(sai)結(jie)構(gou)(gou)。

3、電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)按照功能(neng)分類：水(shui)用(yong)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、蒸(zheng)汽(qi)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、制(zhi)冷電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、低溫(wen)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、燃氣電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、消防(fang)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、氨用(yong)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、氣體電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、液體電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、微型電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、脈沖(chong)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、液壓電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa) 常開電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、油用(yong)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、直流電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、高壓電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、防(fang)爆電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)等(deng)。