電(dian)磁閥(fa)(fa)（Electromagnetic valve）是(shi)用(yong)電(dian)磁控制(zhi)(zhi)的(de)(de)(de)工(gong)業設備，是(shi)用(yong)來(lai)控制(zhi)(zhi)流體的(de)(de)(de)自動(dong)(dong)化基礎元件，屬(shu)于(yu)執(zhi)行器，并不(bu)(bu)限于(yu)液(ye)壓、氣動(dong)(dong)。用(yong)在(zai)(zai)工(gong)業控制(zhi)(zhi)系統中(zhong)調(diao)整(zheng)介質的(de)(de)(de)方(fang)向、流量(liang)、速(su)度和其他(ta)的(de)(de)(de)參數。電(dian)磁閥(fa)(fa)可以(yi)配(pei)合不(bu)(bu)同的(de)(de)(de)電(dian)路(lu)來(lai)實現預期的(de)(de)(de)控制(zhi)(zhi)，而控制(zhi)(zhi)的(de)(de)(de)精(jing)度和靈活性都能夠(gou)保證。電(dian)磁閥(fa)(fa)有很多(duo)種(zhong)，不(bu)(bu)同的(de)(de)(de)電(dian)磁閥(fa)(fa)在(zai)(zai)控制(zhi)(zhi)系統的(de)(de)(de)不(bu)(bu)同位置發揮作(zuo)用(yong)，最常用(yong)的(de)(de)(de)是(shi)單向閥(fa)(fa)、安全閥(fa)(fa)、方(fang)向控制(zhi)(zhi)閥(fa)(fa)、速(su)度調(diao)節閥(fa)(fa)等。

電(dian)(dian)磁(ci)閥里有(you)密閉的腔(qiang)，在不同(tong)位置開有(you)通(tong)孔，每(mei)個孔連接不同(tong)的油(you)管，腔(qiang)中間是(shi)活(huo)(huo)塞(sai)，兩面是(shi)兩塊電(dian)(dian)磁(ci)鐵(tie)，哪(na)面的磁(ci)鐵(tie)線(xian)圈通(tong)電(dian)(dian)閥體就會被吸引到哪(na)邊，通(tong)過(guo)(guo)控(kong)制(zhi)閥體的移動(dong)來開啟或關閉不同(tong)的排(pai)油(you)孔，而進油(you)孔是(shi)常開的，液壓油(you)就會進入不同(tong)的排(pai)油(you)管，然后通(tong)過(guo)(guo)油(you)的壓力來推動(dong)油(you)缸的活(huo)(huo)塞(sai)，活(huo)(huo)塞(sai)又帶動(dong)活(huo)(huo)塞(sai)桿，活(huo)(huo)塞(sai)桿帶動(dong)機械裝置。這樣通(tong)過(guo)(guo)控(kong)制(zhi)電(dian)(dian)磁(ci)鐵(tie)的電(dian)(dian)流通(tong)斷就控(kong)制(zhi)了(le)機械運動(dong)。

1、電磁閥(fa)從(cong)原理上分為(wei)三大(da)類：

直動(dong)式電(dian)磁閥

原理：通(tong)電(dian)時(shi)，電(dian)磁線圈產生電(dian)磁力把關(guan)閉件從閥(fa)座(zuo)(zuo)上提(ti)起(qi)，閥(fa)門打開；斷電(dian)時(shi)，電(dian)磁力消失，彈簧把關(guan)閉件壓在(zai)閥(fa)座(zuo)(zuo)上，閥(fa)門關(guan)閉。

特點：在(zai)真(zhen)空、負壓、零壓時(shi)能正常工(gong)作，但通徑(jing)一般不超過25mm。

分(fen)步(bu)直動式電磁閥

原(yuan)理：它是一種直動和(he)先導(dao)(dao)式相(xiang)結合(he)的(de)原(yuan)理，當(dang)入口(kou)(kou)與(yu)出口(kou)(kou)沒有壓差時，通電(dian)(dian)后，電(dian)(dian)磁(ci)(ci)力(li)(li)直接把(ba)(ba)先導(dao)(dao)小(xiao)(xiao)閥(fa)和(he)主(zhu)閥(fa)關閉件(jian)依次(ci)向上(shang)提起，閥(fa)門打開(kai)(kai)。當(dang)入口(kou)(kou)與(yu)出口(kou)(kou)達到(dao)啟動壓差時，通電(dian)(dian)后，電(dian)(dian)磁(ci)(ci)力(li)(li)先導(dao)(dao)小(xiao)(xiao)閥(fa)，主(zhu)閥(fa)下腔(qiang)壓力(li)(li)上(shang)升，上(shang)腔(qiang)壓力(li)(li)下降，從而利用(yong)壓差把(ba)(ba)主(zhu)閥(fa)向上(shang)推開(kai)(kai)；斷(duan)電(dian)(dian)時，先導(dao)(dao)閥(fa)利用(yong)彈簧力(li)(li)或介(jie)質壓力(li)(li)推動關閉件(jian)，向下移動，使(shi)閥(fa)門關閉。

特點：在(zai)零壓(ya)差或(huo)真空、高壓(ya)時亦(yi)能可(ke)*動(dong)作，但功率較(jiao)大，要求(qiu)必須水平安(an)裝。

先(xian)導式電磁(ci)閥

原(yuan)理：通(tong)電時，電磁(ci)力把先導(dao)孔(kong)打開，上(shang)腔室(shi)壓力迅速下降，在關(guan) 閉(bi)(bi)(bi)件(jian)(jian)周圍形成(cheng)上(shang)低(di)下高的壓差，流體壓力推(tui)動(dong)關(guan)閉(bi)(bi)(bi)件(jian)(jian)向(xiang)上(shang)移動(dong)，閥門(men)打開；斷電時，彈簧力把先導(dao)孔(kong)關(guan)閉(bi)(bi)(bi)，入口壓力通(tong)過旁通(tong)孔(kong)迅速腔室(shi)在關(guan)閥件(jian)(jian)周圍形成(cheng)下低(di)上(shang)高的壓差，流體壓力推(tui)動(dong)關(guan)閉(bi)(bi)(bi)件(jian)(jian)向(xiang)下移動(dong)，關(guan)閉(bi)(bi)(bi)閥門(men)。

特(te)點：流(liu)體(ti)壓(ya)力(li)范(fan)圍上(shang)限(xian)較高(gao)，可任意安裝(zhuang)（需(xu)定(ding)制）但必須滿(man)足流(liu)體(ti)壓(ya)差(cha)條件。

2、電磁(ci)閥從閥結(jie)(jie)構(gou)(gou)和材料(liao)上的不同與原理上的區別，分(fen)為(wei)六個分(fen)支小(xiao)類：直動膜(mo)片(pian)結(jie)(jie)構(gou)(gou)、分(fen)步直動膜(mo)片(pian)結(jie)(jie)構(gou)(gou)、先(xian)導膜(mo)片(pian)結(jie)(jie)構(gou)(gou)、直動活(huo)(huo)塞結(jie)(jie)構(gou)(gou)、分(fen)步直動活(huo)(huo)塞結(jie)(jie)構(gou)(gou)、先(xian)導活(huo)(huo)塞結(jie)(jie)構(gou)(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)按照功能(neng)分類：水用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、蒸(zheng)汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、制冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、低(di)溫電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、燃氣電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、消防(fang)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、氨用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、氣體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、液(ye)體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、微(wei)型電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、脈沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、液(ye)壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa) 常開(kai)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、油用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、直流(liu)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、高壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、防(fang)爆(bao)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)等。