電磁(ci)閥(fa)(fa)（Electromagnetic valve）是用電磁(ci)控(kong)(kong)制(zhi)的(de)工(gong)業(ye)(ye)設(she)備，是用來控(kong)(kong)制(zhi)流體的(de)自動化基礎元件，屬于執行器(qi)，并不限于液壓、氣動。用在(zai)工(gong)業(ye)(ye)控(kong)(kong)制(zhi)系統(tong)中調(diao)整介質的(de)方向(xiang)、流量、速度和其他的(de)參數(shu)。電磁(ci)閥(fa)(fa)可以配(pei)合不同(tong)的(de)電路來實現預期的(de)控(kong)(kong)制(zhi)，而控(kong)(kong)制(zhi)的(de)精度和靈活性都能夠保證。電磁(ci)閥(fa)(fa)有很(hen)多(duo)種，不同(tong)的(de)電磁(ci)閥(fa)(fa)在(zai)控(kong)(kong)制(zhi)系統(tong)的(de)不同(tong)位(wei)置發揮(hui)作用，最常用的(de)是單向(xiang)閥(fa)(fa)、安全閥(fa)(fa)、方向(xiang)控(kong)(kong)制(zhi)閥(fa)(fa)、速度調(diao)節閥(fa)(fa)等(deng)。

電(dian)磁閥(fa)里有密閉(bi)的(de)(de)腔(qiang)，在不同(tong)(tong)位置開有通(tong)孔(kong)，每(mei)個孔(kong)連接不同(tong)(tong)的(de)(de)油(you)(you)管，腔(qiang)中間(jian)是活(huo)塞，兩(liang)面是兩(liang)塊電(dian)磁鐵，哪面的(de)(de)磁鐵線(xian)圈通(tong)電(dian)閥(fa)體(ti)就會被吸引到哪邊，通(tong)過(guo)控制(zhi)閥(fa)體(ti)的(de)(de)移動(dong)來開啟或關閉(bi)不同(tong)(tong)的(de)(de)排油(you)(you)孔(kong)，而(er)進油(you)(you)孔(kong)是常開的(de)(de)，液壓(ya)油(you)(you)就會進入不同(tong)(tong)的(de)(de)排油(you)(you)管，然后通(tong)過(guo)油(you)(you)的(de)(de)壓(ya)力來推動(dong)油(you)(you)缸(gang)的(de)(de)活(huo)塞，活(huo)塞又帶動(dong)活(huo)塞桿，活(huo)塞桿帶動(dong)機械(xie)裝(zhuang)置。這(zhe)樣通(tong)過(guo)控制(zhi)電(dian)磁鐵的(de)(de)電(dian)流通(tong)斷就控制(zhi)了機械(xie)運(yun)動(dong)。

1、電磁閥從原理上(shang)分(fen)為三大類：

直動式電磁閥(fa)

原理：通(tong)電(dian)(dian)(dian)時，電(dian)(dian)(dian)磁(ci)線圈產生電(dian)(dian)(dian)磁(ci)力把關閉件(jian)從(cong)閥(fa)(fa)座上提起，閥(fa)(fa)門打開；斷電(dian)(dian)(dian)時，電(dian)(dian)(dian)磁(ci)力消失(shi)，彈簧把關閉件(jian)壓在閥(fa)(fa)座上，閥(fa)(fa)門關閉。

特點：在真(zhen)空、負壓(ya)(ya)、零壓(ya)(ya)時(shi)能正常工作，但通(tong)徑一般不超過25mm。

分步直動(dong)式電磁閥

原理：它是(shi)一(yi)種直動和先導式相結合的(de)原理，當入(ru)口與出口沒有壓差時，通電(dian)(dian)后(hou)(hou)，電(dian)(dian)磁(ci)(ci)力(li)(li)直接把先導小(xiao)閥(fa)和主閥(fa)關(guan)閉(bi)件(jian)依次向(xiang)上(shang)提起，閥(fa)門(men)打開。當入(ru)口與出口達到啟動壓差時，通電(dian)(dian)后(hou)(hou)，電(dian)(dian)磁(ci)(ci)力(li)(li)先導小(xiao)閥(fa)，主閥(fa)下腔壓力(li)(li)上(shang)升，上(shang)腔壓力(li)(li)下降，從而利用(yong)壓差把主閥(fa)向(xiang)上(shang)推開；斷電(dian)(dian)時，先導閥(fa)利用(yong)彈(dan)簧力(li)(li)或介質壓力(li)(li)推動關(guan)閉(bi)件(jian)，向(xiang)下移動，使閥(fa)門(men)關(guan)閉(bi)。

特點(dian)：在零壓(ya)差或真空、高(gao)壓(ya)時亦能可*動作，但功率較大，要求(qiu)必須水平安裝。

先導式電磁閥

原理：通(tong)電(dian)時，電(dian)磁力(li)(li)把先導孔(kong)打開，上(shang)(shang)腔室壓(ya)力(li)(li)迅速下(xia)(xia)降，在關(guan) 閉(bi)件周(zhou)圍(wei)形(xing)成(cheng)上(shang)(shang)低下(xia)(xia)高(gao)的壓(ya)差(cha)，流體壓(ya)力(li)(li)推動關(guan)閉(bi)件向上(shang)(shang)移動，閥(fa)門(men)打開；斷電(dian)時，彈簧力(li)(li)把先導孔(kong)關(guan)閉(bi)，入口壓(ya)力(li)(li)通(tong)過旁通(tong)孔(kong)迅速腔室在關(guan)閥(fa)件周(zhou)圍(wei)形(xing)成(cheng)下(xia)(xia)低上(shang)(shang)高(gao)的壓(ya)差(cha)，流體壓(ya)力(li)(li)推動關(guan)閉(bi)件向下(xia)(xia)移動，關(guan)閉(bi)閥(fa)門(men)。

特(te)點：流(liu)體(ti)壓力范圍上限較高，可(ke)任意安(an)裝(zhuang)（需定(ding)制）但必須滿(man)足流(liu)體(ti)壓差條件(jian)。

2、電磁閥從(cong)閥結(jie)構(gou)和材料上(shang)的(de)不同與原理上(shang)的(de)區別，分為六個分支小類：直(zhi)動膜片(pian)結(jie)構(gou)、分步直(zhi)動膜片(pian)結(jie)構(gou)、先(xian)導(dao)膜片(pian)結(jie)構(gou)、直(zhi)動活(huo)塞(sai)(sai)結(jie)構(gou)、分步直(zhi)動活(huo)塞(sai)(sai)結(jie)構(gou)、先(xian)導(dao)活(huo)塞(sai)(sai)結(jie)構(gou)。

3、電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)按照(zhao)功(gong)能分類：水用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、制冷電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、低溫電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、氨用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、氣(qi)體電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、液體電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、微型(xing)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、液壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa) 常開電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、油用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、直流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、高壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、防(fang)爆(bao)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)等。