電(dian)磁閥(fa)（Electromagnetic valve）是(shi)用(yong)電(dian)磁控(kong)制的(de)(de)(de)工(gong)業(ye)(ye)設備，是(shi)用(yong)來(lai)控(kong)制流體的(de)(de)(de)自動(dong)化基礎元件，屬于執行器，并不限于液壓、氣動(dong)。用(yong)在工(gong)業(ye)(ye)控(kong)制系(xi)統中調(diao)整介(jie)質的(de)(de)(de)方向、流量(liang)、速度(du)和其他的(de)(de)(de)參數(shu)。電(dian)磁閥(fa)可以(yi)配合不同(tong)的(de)(de)(de)電(dian)路來(lai)實現預期的(de)(de)(de)控(kong)制，而(er)控(kong)制的(de)(de)(de)精度(du)和靈活性(xing)都能夠保證。電(dian)磁閥(fa)有很(hen)多種，不同(tong)的(de)(de)(de)電(dian)磁閥(fa)在控(kong)制系(xi)統的(de)(de)(de)不同(tong)位置發揮作用(yong)，最常用(yong)的(de)(de)(de)是(shi)單向閥(fa)、安(an)全閥(fa)、方向控(kong)制閥(fa)、速度(du)調(diao)節閥(fa)等。

電(dian)磁(ci)閥(fa)里有密閉的腔，在不同(tong)位置(zhi)開有通(tong)孔(kong)，每個孔(kong)連接不同(tong)的油(you)(you)管，腔中間是活(huo)塞(sai)，兩面是兩塊(kuai)電(dian)磁(ci)鐵，哪面的磁(ci)鐵線(xian)圈通(tong)電(dian)閥(fa)體(ti)就會被吸(xi)引到哪邊(bian)，通(tong)過控(kong)制閥(fa)體(ti)的移動來開啟或(huo)關閉不同(tong)的排油(you)(you)孔(kong)，而進油(you)(you)孔(kong)是常開的，液壓油(you)(you)就會進入不同(tong)的排油(you)(you)管，然后通(tong)過油(you)(you)的壓力(li)來推(tui)動油(you)(you)缸的活(huo)塞(sai)，活(huo)塞(sai)又帶動活(huo)塞(sai)桿(gan)，活(huo)塞(sai)桿(gan)帶動機(ji)械(xie)裝置(zhi)。這(zhe)樣通(tong)過控(kong)制電(dian)磁(ci)鐵的電(dian)流通(tong)斷就控(kong)制了機(ji)械(xie)運動。

1、電磁閥從原理(li)上(shang)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(sheng)電(dian)磁力(li)把關(guan)閉件(jian)從閥(fa)座上提起，閥(fa)門(men)打開；斷(duan)電(dian)時，電(dian)磁力(li)消失，彈簧把關(guan)閉件(jian)壓在閥(fa)座上，閥(fa)門(men)關(guan)閉。

特(te)點(dian)：在真空、負壓、零壓時(shi)能正常工作，但通徑一般不超過25mm。

分步直動式電磁閥(fa)

原理(li)：它是一(yi)種直動(dong)和先導式相結(jie)合的(de)原理(li)，當入口與出口沒有(you)壓(ya)(ya)差時(shi)(shi)，通(tong)電后(hou)，電磁力直接把(ba)先導小閥(fa)(fa)和主(zhu)閥(fa)(fa)關閉(bi)件依次向(xiang)上提(ti)起，閥(fa)(fa)門(men)打(da)開。當入口與出口達到啟動(dong)壓(ya)(ya)差時(shi)(shi)，通(tong)電后(hou)，電磁力先導小閥(fa)(fa)，主(zhu)閥(fa)(fa)下腔壓(ya)(ya)力上升(sheng)，上腔壓(ya)(ya)力下降，從而利用(yong)(yong)壓(ya)(ya)差把(ba)主(zhu)閥(fa)(fa)向(xiang)上推(tui)開；斷電時(shi)(shi)，先導閥(fa)(fa)利用(yong)(yong)彈(dan)簧力或(huo)介質壓(ya)(ya)力推(tui)動(dong)關閉(bi)件，向(xiang)下移動(dong)，使閥(fa)(fa)門(men)關閉(bi)。

特點(dian)：在零壓(ya)差或(huo)真空、高(gao)壓(ya)時(shi)亦能(neng)可*動作(zuo)，但功率(lv)較大，要求必須(xu)水(shui)平安裝。

先(xian)導式(shi)電磁閥

原(yuan)理：通(tong)電時，電磁(ci)力把先(xian)導孔(kong)打開，上(shang)(shang)(shang)腔室壓(ya)(ya)力迅(xun)速(su)下降(jiang)，在關(guan) 閉(bi)件(jian)周(zhou)圍形成(cheng)上(shang)(shang)(shang)低(di)下高的(de)壓(ya)(ya)差(cha)(cha)，流體壓(ya)(ya)力推動關(guan)閉(bi)件(jian)向上(shang)(shang)(shang)移動，閥(fa)門打開；斷電時，彈簧力把先(xian)導孔(kong)關(guan)閉(bi)，入口壓(ya)(ya)力通(tong)過(guo)旁通(tong)孔(kong)迅(xun)速(su)腔室在關(guan)閥(fa)件(jian)周(zhou)圍形成(cheng)下低(di)上(shang)(shang)(shang)高的(de)壓(ya)(ya)差(cha)(cha)，流體壓(ya)(ya)力推動關(guan)閉(bi)件(jian)向下移動，關(guan)閉(bi)閥(fa)門。

特點：流(liu)體(ti)(ti)壓(ya)(ya)力范圍上限較高，可任意安裝（需定制）但必須滿足流(liu)體(ti)(ti)壓(ya)(ya)差條件。

2、電(dian)磁閥(fa)從閥(fa)結構(gou)和材料(liao)上(shang)的(de)不(bu)同與原(yuan)理上(shang)的(de)區別，分為六個(ge)分支小類：直(zhi)動(dong)(dong)膜(mo)片結構(gou)、分步(bu)直(zhi)動(dong)(dong)膜(mo)片結構(gou)、先(xian)導膜(mo)片結構(gou)、直(zhi)動(dong)(dong)活塞結構(gou)、分步(bu)直(zhi)動(dong)(dong)活塞結構(gou)、先(xian)導活塞結構(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)按照功(gong)能分(fen)類：水用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、氨用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、氣(qi)體(ti)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、液(ye)體(ti)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、微型(xing)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、脈(mo)沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、液(ye)壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、油(you)用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、直流(liu)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、防(fang)爆(bao)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)等。