電磁(ci)閥(fa)（Electromagnetic valve）是用(yong)(yong)(yong)電磁(ci)控制(zhi)(zhi)的(de)(de)(de)工(gong)業設(she)備，是用(yong)(yong)(yong)來控制(zhi)(zhi)流體(ti)的(de)(de)(de)自動(dong)化基礎元件，屬于執行(xing)器(qi)，并不(bu)(bu)限(xian)于液(ye)壓(ya)、氣(qi)動(dong)。用(yong)(yong)(yong)在(zai)工(gong)業控制(zhi)(zhi)系統(tong)中(zhong)調(diao)(diao)整(zheng)介質的(de)(de)(de)方向(xiang)、流量、速度和其他的(de)(de)(de)參數(shu)。電磁(ci)閥(fa)可以(yi)配合不(bu)(bu)同的(de)(de)(de)電路來實現(xian)預(yu)期(qi)的(de)(de)(de)控制(zhi)(zhi)，而控制(zhi)(zhi)的(de)(de)(de)精度和靈(ling)活性都能夠保證(zheng)。電磁(ci)閥(fa)有很多種，不(bu)(bu)同的(de)(de)(de)電磁(ci)閥(fa)在(zai)控制(zhi)(zhi)系統(tong)的(de)(de)(de)不(bu)(bu)同位置發揮作用(yong)(yong)(yong)，最常用(yong)(yong)(yong)的(de)(de)(de)是單向(xiang)閥(fa)、安全(quan)閥(fa)、方向(xiang)控制(zhi)(zhi)閥(fa)、速度調(diao)(diao)節閥(fa)等。

電(dian)(dian)磁(ci)(ci)閥里有密(mi)閉(bi)的(de)(de)腔，在不(bu)同位置(zhi)開有通(tong)(tong)孔，每(mei)個孔連(lian)接(jie)不(bu)同的(de)(de)油(you)管，腔中(zhong)間是活(huo)塞(sai)(sai)，兩面(mian)是兩塊電(dian)(dian)磁(ci)(ci)鐵(tie)，哪面(mian)的(de)(de)磁(ci)(ci)鐵(tie)線圈通(tong)(tong)電(dian)(dian)閥體就(jiu)會被吸引到哪邊，通(tong)(tong)過控制(zhi)閥體的(de)(de)移動(dong)來開啟或關閉(bi)不(bu)同的(de)(de)排(pai)(pai)油(you)孔，而進油(you)孔是常開的(de)(de)，液壓(ya)油(you)就(jiu)會進入(ru)不(bu)同的(de)(de)排(pai)(pai)油(you)管，然后通(tong)(tong)過油(you)的(de)(de)壓(ya)力(li)來推(tui)動(dong)油(you)缸的(de)(de)活(huo)塞(sai)(sai)，活(huo)塞(sai)(sai)又帶動(dong)活(huo)塞(sai)(sai)桿，活(huo)塞(sai)(sai)桿帶動(dong)機械裝置(zhi)。這(zhe)樣(yang)通(tong)(tong)過控制(zhi)電(dian)(dian)磁(ci)(ci)鐵(tie)的(de)(de)電(dian)(dian)流通(tong)(tong)斷就(jiu)控制(zhi)了機械運(yun)動(dong)。

1、電磁閥從原理上分為(wei)三大類：

直動式電磁閥

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

特點：在真空、負壓、零壓時能正常(chang)工作，但通徑一般不超(chao)過(guo)25mm。

分步直動式電磁(ci)閥

原(yuan)理：它(ta)是(shi)一種(zhong)直動(dong)和(he)先導式相結合的原(yuan)理，當入(ru)口(kou)(kou)與(yu)出口(kou)(kou)沒有(you)壓(ya)(ya)差(cha)時(shi)，通電后，電磁力(li)直接把先導小閥(fa)(fa)和(he)主閥(fa)(fa)關閉(bi)件(jian)(jian)依次向(xiang)(xiang)上(shang)提起，閥(fa)(fa)門(men)打開。當入(ru)口(kou)(kou)與(yu)出口(kou)(kou)達(da)到啟動(dong)壓(ya)(ya)差(cha)時(shi)，通電后，電磁力(li)先導小閥(fa)(fa)，主閥(fa)(fa)下(xia)腔(qiang)壓(ya)(ya)力(li)上(shang)升(sheng)，上(shang)腔(qiang)壓(ya)(ya)力(li)下(xia)降，從而(er)利用(yong)壓(ya)(ya)差(cha)把主閥(fa)(fa)向(xiang)(xiang)上(shang)推開；斷電時(shi)，先導閥(fa)(fa)利用(yong)彈簧力(li)或介質壓(ya)(ya)力(li)推動(dong)關閉(bi)件(jian)(jian)，向(xiang)(xiang)下(xia)移(yi)動(dong)，使閥(fa)(fa)門(men)關閉(bi)。

特點：在零壓(ya)差或真(zhen)空、高壓(ya)時亦能可*動(dong)作(zuo)，但功率較大，要求必須水平安裝。

先導式電磁閥

原理(li)：通(tong)電(dian)(dian)時，電(dian)(dian)磁力(li)把先導(dao)孔(kong)打(da)開(kai)，上(shang)腔室壓力(li)迅速下(xia)(xia)降，在(zai)關(guan) 閉件(jian)周(zhou)圍形成(cheng)上(shang)低下(xia)(xia)高的壓差(cha)，流體(ti)壓力(li)推(tui)動(dong)關(guan)閉件(jian)向上(shang)移動(dong)，閥門打(da)開(kai)；斷電(dian)(dian)時，彈(dan)簧(huang)力(li)把先導(dao)孔(kong)關(guan)閉，入(ru)口壓力(li)通(tong)過(guo)旁通(tong)孔(kong)迅速腔室在(zai)關(guan)閥件(jian)周(zhou)圍形成(cheng)下(xia)(xia)低上(shang)高的壓差(cha)，流體(ti)壓力(li)推(tui)動(dong)關(guan)閉件(jian)向下(xia)(xia)移動(dong)，關(guan)閉閥門。

特(te)點：流體(ti)壓力范圍上限較高(gao)，可任(ren)意(yi)安裝（需定制）但必須滿足流體(ti)壓差條件。

2、電磁閥從閥結(jie)(jie)構(gou)(gou)和材料上的(de)不同與原理(li)上的(de)區(qu)別(bie)，分(fen)為(wei)六(liu)個分(fen)支小(xiao)類：直(zhi)動膜(mo)片(pian)結(jie)(jie)構(gou)(gou)、分(fen)步直(zhi)動膜(mo)片(pian)結(jie)(jie)構(gou)(gou)、先(xian)導膜(mo)片(pian)結(jie)(jie)構(gou)(gou)、直(zhi)動活(huo)(huo)(huo)塞(sai)結(jie)(jie)構(gou)(gou)、分(fen)步直(zhi)動活(huo)(huo)(huo)塞(sai)結(jie)(jie)構(gou)(gou)、先(xian)導活(huo)(huo)(huo)塞(sai)結(jie)(jie)構(gou)(gou)。

3、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)按照功能(neng)分類(lei)：水用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、制(zhi)冷(leng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、低溫(wen)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、氨用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、液(ye)體電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、液(ye)壓電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、油用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、直(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、防(fang)爆電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)等(deng)。