電(dian)磁(ci)閥(fa)（Electromagnetic valve）是(shi)用電(dian)磁(ci)控(kong)制(zhi)(zhi)(zhi)的(de)(de)工業(ye)設備，是(shi)用來控(kong)制(zhi)(zhi)(zhi)流體的(de)(de)自動化基礎元件，屬(shu)于(yu)執行(xing)器，并不(bu)(bu)(bu)限于(yu)液壓、氣動。用在工業(ye)控(kong)制(zhi)(zhi)(zhi)系(xi)統中(zhong)調整介質的(de)(de)方(fang)向、流量、速度(du)和(he)其他的(de)(de)參數。電(dian)磁(ci)閥(fa)可以配(pei)合不(bu)(bu)(bu)同的(de)(de)電(dian)路來實現預期的(de)(de)控(kong)制(zhi)(zhi)(zhi)，而控(kong)制(zhi)(zhi)(zhi)的(de)(de)精度(du)和(he)靈活性都能(neng)夠(gou)保(bao)證。電(dian)磁(ci)閥(fa)有很多(duo)種，不(bu)(bu)(bu)同的(de)(de)電(dian)磁(ci)閥(fa)在控(kong)制(zhi)(zhi)(zhi)系(xi)統的(de)(de)不(bu)(bu)(bu)同位置發揮作用，最常用的(de)(de)是(shi)單向閥(fa)、安(an)全閥(fa)、方(fang)向控(kong)制(zhi)(zhi)(zhi)閥(fa)、速度(du)調節閥(fa)等。

電(dian)磁閥(fa)里有密(mi)閉的(de)腔(qiang)，在不同(tong)(tong)位置開(kai)有通(tong)孔(kong)，每個(ge)孔(kong)連接不同(tong)(tong)的(de)油(you)管(guan)，腔(qiang)中間(jian)是活(huo)(huo)(huo)塞(sai)，兩面(mian)是兩塊電(dian)磁鐵(tie)，哪面(mian)的(de)磁鐵(tie)線圈通(tong)電(dian)閥(fa)體就(jiu)會(hui)被(bei)吸(xi)引(yin)到(dao)哪邊，通(tong)過(guo)控制閥(fa)體的(de)移動來開(kai)啟或(huo)關閉不同(tong)(tong)的(de)排(pai)油(you)孔(kong)，而進油(you)孔(kong)是常開(kai)的(de)，液壓油(you)就(jiu)會(hui)進入不同(tong)(tong)的(de)排(pai)油(you)管(guan)，然后通(tong)過(guo)油(you)的(de)壓力來推動油(you)缸的(de)活(huo)(huo)(huo)塞(sai)，活(huo)(huo)(huo)塞(sai)又帶動活(huo)(huo)(huo)塞(sai)桿，活(huo)(huo)(huo)塞(sai)桿帶動機械裝置。這樣通(tong)過(guo)控制電(dian)磁鐵(tie)的(de)電(dian)流通(tong)斷(duan)就(jiu)控制了機械運動。

1、電磁閥(fa)從原(yuan)理上分(fen)為三大(da)類：

直(zhi)動式電磁(ci)閥

原理(li)：通電(dian)(dian)時，電(dian)(dian)磁(ci)線(xian)圈產生電(dian)(dian)磁(ci)力把關(guan)閉件從閥座(zuo)上提起，閥門打開；斷電(dian)(dian)時，電(dian)(dian)磁(ci)力消失，彈簧把關(guan)閉件壓在閥座(zuo)上，閥門關(guan)閉。

特點：在真空、負壓、零壓時能正常工作，但通徑一(yi)般不(bu)超過25mm。

分步直動(dong)式電磁(ci)閥

原理：它(ta)是(shi)一種(zhong)直動(dong)和先導(dao)式(shi)相結(jie)合的(de)原理，當(dang)入口與出口沒有壓(ya)(ya)差(cha)(cha)時，通電(dian)后，電(dian)磁(ci)力(li)直接把(ba)先導(dao)小(xiao)閥(fa)(fa)和主閥(fa)(fa)關閉(bi)件依次(ci)向(xiang)上(shang)提起，閥(fa)(fa)門打開。當(dang)入口與出口達到(dao)啟(qi)動(dong)壓(ya)(ya)差(cha)(cha)時，通電(dian)后，電(dian)磁(ci)力(li)先導(dao)小(xiao)閥(fa)(fa)，主閥(fa)(fa)下腔(qiang)壓(ya)(ya)力(li)上(shang)升，上(shang)腔(qiang)壓(ya)(ya)力(li)下降，從(cong)而利(li)用(yong)壓(ya)(ya)差(cha)(cha)把(ba)主閥(fa)(fa)向(xiang)上(shang)推開；斷電(dian)時，先導(dao)閥(fa)(fa)利(li)用(yong)彈簧力(li)或介質壓(ya)(ya)力(li)推動(dong)關閉(bi)件，向(xiang)下移動(dong)，使閥(fa)(fa)門關閉(bi)。

特點(dian)：在(zai)零壓(ya)差或真空、高壓(ya)時(shi)亦(yi)能可*動作，但功率較大，要(yao)求必須(xu)水平(ping)安裝。

先導式電磁閥(fa)

原理：通(tong)(tong)電(dian)(dian)時(shi)，電(dian)(dian)磁力把先(xian)導孔打(da)開(kai)，上腔室壓(ya)(ya)力迅速(su)下(xia)降(jiang)，在關 閉(bi)(bi)件(jian)(jian)周圍(wei)形(xing)成(cheng)上低下(xia)高的(de)(de)壓(ya)(ya)差(cha)，流體壓(ya)(ya)力推動(dong)(dong)關閉(bi)(bi)件(jian)(jian)向上移動(dong)(dong)，閥門(men)打(da)開(kai)；斷電(dian)(dian)時(shi)，彈簧(huang)力把先(xian)導孔關閉(bi)(bi)，入(ru)口壓(ya)(ya)力通(tong)(tong)過(guo)旁通(tong)(tong)孔迅速(su)腔室在關閥件(jian)(jian)周圍(wei)形(xing)成(cheng)下(xia)低上高的(de)(de)壓(ya)(ya)差(cha)，流體壓(ya)(ya)力推動(dong)(dong)關閉(bi)(bi)件(jian)(jian)向下(xia)移動(dong)(dong)，關閉(bi)(bi)閥門(men)。

特點：流體壓力范圍上(shang)限較高(gao)，可任意(yi)安裝（需定(ding)制）但(dan)必須滿足流體壓差條件。

2、電磁閥從閥結(jie)(jie)構(gou)和材料(liao)上(shang)的不同與原理上(shang)的區別，分(fen)為六(liu)個分(fen)支小(xiao)類：直動膜(mo)片結(jie)(jie)構(gou)、分(fen)步(bu)直動膜(mo)片結(jie)(jie)構(gou)、先(xian)導(dao)膜(mo)片結(jie)(jie)構(gou)、直動活(huo)塞(sai)結(jie)(jie)構(gou)、分(fen)步(bu)直動活(huo)塞(sai)結(jie)(jie)構(gou)、先(xian)導(dao)活(huo)塞(sai)結(jie)(jie)構(gou)。

3、電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)按照(zhao)功(gong)能分類(lei)：水用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、消(xiao)防電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、氨(an)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、液(ye)體電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、液(ye)壓電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、油用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)、防爆電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)等。