電磁閥(fa)(fa)（Electromagnetic valve）是(shi)用電磁控制(zhi)(zhi)的(de)(de)(de)工業(ye)設備，是(shi)用來(lai)控制(zhi)(zhi)流體的(de)(de)(de)自動(dong)化基礎元件，屬于執(zhi)行器(qi)，并不限(xian)于液壓、氣(qi)動(dong)。用在(zai)工業(ye)控制(zhi)(zhi)系統中調(diao)整介質的(de)(de)(de)方向(xiang)、流量、速度(du)和其他(ta)的(de)(de)(de)參數(shu)。電磁閥(fa)(fa)可以配合不同的(de)(de)(de)電路來(lai)實現預期(qi)的(de)(de)(de)控制(zhi)(zhi)，而(er)控制(zhi)(zhi)的(de)(de)(de)精度(du)和靈活(huo)性都能夠保證。電磁閥(fa)(fa)有很多種(zhong)，不同的(de)(de)(de)電磁閥(fa)(fa)在(zai)控制(zhi)(zhi)系統的(de)(de)(de)不同位置發揮作(zuo)用，最常用的(de)(de)(de)是(shi)單向(xiang)閥(fa)(fa)、安全閥(fa)(fa)、方向(xiang)控制(zhi)(zhi)閥(fa)(fa)、速度(du)調(diao)節閥(fa)(fa)等(deng)。

電(dian)磁(ci)閥里有密閉的(de)(de)(de)腔(qiang)，在不(bu)(bu)同(tong)位置(zhi)開有通(tong)(tong)孔(kong)(kong)，每(mei)個孔(kong)(kong)連(lian)接不(bu)(bu)同(tong)的(de)(de)(de)油(you)管，腔(qiang)中間是(shi)活(huo)塞(sai)(sai)，兩(liang)面(mian)是(shi)兩(liang)塊電(dian)磁(ci)鐵(tie)(tie)，哪面(mian)的(de)(de)(de)磁(ci)鐵(tie)(tie)線圈通(tong)(tong)電(dian)閥體(ti)就(jiu)會被吸引到哪邊，通(tong)(tong)過(guo)(guo)控(kong)制閥體(ti)的(de)(de)(de)移動來(lai)開啟或關閉不(bu)(bu)同(tong)的(de)(de)(de)排油(you)孔(kong)(kong)，而進油(you)孔(kong)(kong)是(shi)常開的(de)(de)(de)，液壓油(you)就(jiu)會進入不(bu)(bu)同(tong)的(de)(de)(de)排油(you)管，然后(hou)通(tong)(tong)過(guo)(guo)油(you)的(de)(de)(de)壓力來(lai)推(tui)動油(you)缸的(de)(de)(de)活(huo)塞(sai)(sai)，活(huo)塞(sai)(sai)又帶動活(huo)塞(sai)(sai)桿，活(huo)塞(sai)(sai)桿帶動機械裝置(zhi)。這樣通(tong)(tong)過(guo)(guo)控(kong)制電(dian)磁(ci)鐵(tie)(tie)的(de)(de)(de)電(dian)流通(tong)(tong)斷就(jiu)控(kong)制了機械運動。

1、電磁閥從原理上分為三大類：

直動式電磁閥

原理：通電(dian)時，電(dian)磁線(xian)圈產生電(dian)磁力把關(guan)(guan)閉(bi)(bi)件從閥座上(shang)提起(qi)，閥門打開(kai)；斷電(dian)時，電(dian)磁力消(xiao)失，彈簧(huang)把關(guan)(guan)閉(bi)(bi)件壓在閥座上(shang)，閥門關(guan)(guan)閉(bi)(bi)。

特(te)點：在真空、負壓(ya)、零壓(ya)時能正常(chang)工作，但通徑一般不超(chao)過25mm。

分步(bu)直動式(shi)電(dian)磁(ci)閥

原(yuan)理(li)：它(ta)是一種直(zhi)動(dong)和先導(dao)式相結(jie)合的原(yuan)理(li)，當入口(kou)與出(chu)(chu)口(kou)沒有壓(ya)差(cha)時，通電后(hou)，電磁(ci)力(li)直(zhi)接把(ba)先導(dao)小(xiao)(xiao)閥(fa)(fa)和主閥(fa)(fa)關(guan)閉件(jian)依次向(xiang)上提(ti)起，閥(fa)(fa)門(men)打開(kai)。當入口(kou)與出(chu)(chu)口(kou)達到啟動(dong)壓(ya)差(cha)時，通電后(hou)，電磁(ci)力(li)先導(dao)小(xiao)(xiao)閥(fa)(fa)，主閥(fa)(fa)下腔壓(ya)力(li)上升，上腔壓(ya)力(li)下降，從而(er)利用壓(ya)差(cha)把(ba)主閥(fa)(fa)向(xiang)上推(tui)開(kai)；斷電時，先導(dao)閥(fa)(fa)利用彈簧(huang)力(li)或介質壓(ya)力(li)推(tui)動(dong)關(guan)閉件(jian)，向(xiang)下移(yi)動(dong)，使閥(fa)(fa)門(men)關(guan)閉。

特(te)點(dian)：在零壓差或真(zhen)空、高壓時(shi)亦(yi)能可*動作(zuo)，但(dan)功(gong)率較大，要求(qiu)必須(xu)水平安裝。

先導式電磁閥

原理：通電(dian)時，電(dian)磁力(li)把先導孔(kong)打開(kai)，上(shang)腔室壓力(li)迅速下降，在關(guan) 閉件(jian)(jian)周圍形(xing)成上(shang)低下高的壓差，流(liu)(liu)體壓力(li)推動(dong)關(guan)閉件(jian)(jian)向上(shang)移(yi)動(dong)，閥門(men)打開(kai)；斷電(dian)時，彈簧力(li)把先導孔(kong)關(guan)閉，入口(kou)壓力(li)通過旁通孔(kong)迅速腔室在關(guan)閥件(jian)(jian)周圍形(xing)成下低上(shang)高的壓差，流(liu)(liu)體壓力(li)推動(dong)關(guan)閉件(jian)(jian)向下移(yi)動(dong)，關(guan)閉閥門(men)。

特點：流(liu)體(ti)壓力(li)范(fan)圍上限較(jiao)高(gao)，可任(ren)意安裝（需定制）但(dan)必須滿足(zu)流(liu)體(ti)壓差條件。

2、電磁閥從閥結(jie)(jie)(jie)構(gou)和材料上(shang)的不同與原理(li)上(shang)的區別，分(fen)(fen)為六個分(fen)(fen)支小類：直(zhi)動膜片結(jie)(jie)(jie)構(gou)、分(fen)(fen)步直(zhi)動膜片結(jie)(jie)(jie)構(gou)、先導膜片結(jie)(jie)(jie)構(gou)、直(zhi)動活塞結(jie)(jie)(jie)構(gou)、分(fen)(fen)步直(zhi)動活塞結(jie)(jie)(jie)構(gou)、先導活塞結(jie)(jie)(jie)構(gou)。

3、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)按照功能分類：水用電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、制(zhi)冷電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、消防(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、氨(an)用電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、液體電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、液壓電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、油用電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、防(fang)(fang)爆電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)等。