電磁(ci)閥(fa)(fa)(fa)（Electromagnetic valve）是用(yong)電磁(ci)控(kong)制(zhi)(zhi)的(de)(de)(de)(de)工(gong)業設備(bei)，是用(yong)來(lai)控(kong)制(zhi)(zhi)流體(ti)的(de)(de)(de)(de)自動化基礎(chu)元件，屬于(yu)執行(xing)器，并不限于(yu)液(ye)壓、氣動。用(yong)在工(gong)業控(kong)制(zhi)(zhi)系(xi)(xi)統(tong)中調(diao)整介質的(de)(de)(de)(de)方向、流量、速度(du)和其他的(de)(de)(de)(de)參(can)數(shu)。電磁(ci)閥(fa)(fa)(fa)可(ke)以配合不同(tong)(tong)的(de)(de)(de)(de)電路來(lai)實(shi)現預期的(de)(de)(de)(de)控(kong)制(zhi)(zhi)，而(er)控(kong)制(zhi)(zhi)的(de)(de)(de)(de)精度(du)和靈活性都能夠(gou)保證。電磁(ci)閥(fa)(fa)(fa)有很多種，不同(tong)(tong)的(de)(de)(de)(de)電磁(ci)閥(fa)(fa)(fa)在控(kong)制(zhi)(zhi)系(xi)(xi)統(tong)的(de)(de)(de)(de)不同(tong)(tong)位(wei)置(zhi)發揮作用(yong)，最常用(yong)的(de)(de)(de)(de)是單(dan)向閥(fa)(fa)(fa)、安全(quan)閥(fa)(fa)(fa)、方向控(kong)制(zhi)(zhi)閥(fa)(fa)(fa)、速度(du)調(diao)節(jie)閥(fa)(fa)(fa)等。

電(dian)(dian)(dian)磁(ci)(ci)閥(fa)里有(you)密(mi)閉(bi)的(de)(de)(de)腔，在不同位置開有(you)通(tong)孔，每個孔連接不同的(de)(de)(de)油(you)(you)管(guan)，腔中間是活塞，兩面是兩塊電(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)，哪面的(de)(de)(de)磁(ci)(ci)鐵(tie)(tie)線圈通(tong)電(dian)(dian)(dian)閥(fa)體就會(hui)被吸引到哪邊(bian)，通(tong)過(guo)控制閥(fa)體的(de)(de)(de)移動來(lai)開啟或關閉(bi)不同的(de)(de)(de)排油(you)(you)孔，而(er)進油(you)(you)孔是常開的(de)(de)(de)，液壓油(you)(you)就會(hui)進入不同的(de)(de)(de)排油(you)(you)管(guan)，然后通(tong)過(guo)油(you)(you)的(de)(de)(de)壓力來(lai)推動油(you)(you)缸的(de)(de)(de)活塞，活塞又帶動活塞桿，活塞桿帶動機(ji)械裝置。這(zhe)樣通(tong)過(guo)控制電(dian)(dian)(dian)磁(ci)(ci)鐵(tie)(tie)的(de)(de)(de)電(dian)(dian)(dian)流通(tong)斷(duan)就控制了機(ji)械運動。

1、電磁閥從原理上分為三大類(lei)：

直動(dong)式電磁閥

原理：通電(dian)時，電(dian)磁線圈產生電(dian)磁力把關閉件(jian)從閥(fa)座上(shang)(shang)提起，閥(fa)門打開；斷(duan)電(dian)時，電(dian)磁力消失，彈簧把關閉件(jian)壓在(zai)閥(fa)座上(shang)(shang)，閥(fa)門關閉。

特點：在真空、負(fu)壓、零壓時能正(zheng)常工作，但通(tong)徑一般不超過25mm。

分(fen)步直動(dong)式電磁閥

原理(li)：它是一種直動和先導(dao)式相結合的原理(li)，當(dang)入口(kou)(kou)與(yu)出口(kou)(kou)沒(mei)有壓差時，通電(dian)(dian)后(hou)，電(dian)(dian)磁(ci)力直接(jie)把先導(dao)小(xiao)閥(fa)(fa)和主閥(fa)(fa)關(guan)(guan)閉件依次向上(shang)提起，閥(fa)(fa)門打開(kai)(kai)。當(dang)入口(kou)(kou)與(yu)出口(kou)(kou)達(da)到啟動壓差時，通電(dian)(dian)后(hou)，電(dian)(dian)磁(ci)力先導(dao)小(xiao)閥(fa)(fa)，主閥(fa)(fa)下腔(qiang)壓力上(shang)升(sheng)，上(shang)腔(qiang)壓力下降，從而(er)利(li)(li)用(yong)壓差把主閥(fa)(fa)向上(shang)推(tui)開(kai)(kai)；斷電(dian)(dian)時，先導(dao)閥(fa)(fa)利(li)(li)用(yong)彈簧力或介質壓力推(tui)動關(guan)(guan)閉件，向下移(yi)動，使閥(fa)(fa)門關(guan)(guan)閉。

特點(dian)：在零(ling)壓差或真空、高(gao)壓時亦能可(ke)*動作，但功率(lv)較大(da)，要求必(bi)須水平安裝。

先導式(shi)電磁閥

原理：通(tong)電時，電磁(ci)力(li)(li)(li)把先導孔(kong)(kong)打開，上腔室(shi)壓(ya)(ya)力(li)(li)(li)迅(xun)速下降(jiang)，在關(guan) 閉件周圍形成上低下高(gao)的壓(ya)(ya)差(cha)，流體壓(ya)(ya)力(li)(li)(li)推動(dong)關(guan)閉件向上移動(dong)，閥門打開；斷電時，彈簧力(li)(li)(li)把先導孔(kong)(kong)關(guan)閉，入口壓(ya)(ya)力(li)(li)(li)通(tong)過旁通(tong)孔(kong)(kong)迅(xun)速腔室(shi)在關(guan)閥件周圍形成下低上高(gao)的壓(ya)(ya)差(cha)，流體壓(ya)(ya)力(li)(li)(li)推動(dong)關(guan)閉件向下移動(dong)，關(guan)閉閥門。

特點：流(liu)體壓力(li)范圍上(shang)限較高(gao)，可任(ren)意安裝（需定制(zhi)）但必須滿足流(liu)體壓差條件(jian)。

2、電磁閥(fa)從閥(fa)結(jie)(jie)(jie)構(gou)和材(cai)料(liao)上的(de)不同與原理(li)上的(de)區(qu)別，分為六個分支小類：直動(dong)(dong)膜(mo)片結(jie)(jie)(jie)構(gou)、分步直動(dong)(dong)膜(mo)片結(jie)(jie)(jie)構(gou)、先導膜(mo)片結(jie)(jie)(jie)構(gou)、直動(dong)(dong)活塞結(jie)(jie)(jie)構(gou)、分步直動(dong)(dong)活塞結(jie)(jie)(jie)構(gou)、先導活塞結(jie)(jie)(jie)構(gou)。

3、電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)按照功能分類：水用(yong)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、蒸(zheng)汽電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、燃(ran)氣(qi)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、氨用(yong)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、氣(qi)體(ti)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、液體(ti)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、液壓(ya)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、油用(yong)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、直流(liu)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、高壓(ya)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)、防(fang)爆電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)等。