電(dian)(dian)磁閥(fa)（Electromagnetic valve）是用(yong)電(dian)(dian)磁控(kong)(kong)制的(de)(de)工業(ye)(ye)設備，是用(yong)來控(kong)(kong)制流體(ti)的(de)(de)自動化(hua)基礎(chu)元件，屬于執行器，并不(bu)(bu)限于液壓(ya)、氣動。用(yong)在(zai)(zai)工業(ye)(ye)控(kong)(kong)制系(xi)統中調整介質的(de)(de)方(fang)向、流量、速度(du)和其他的(de)(de)參(can)數。電(dian)(dian)磁閥(fa)可以配(pei)合不(bu)(bu)同(tong)的(de)(de)電(dian)(dian)路來實現預期(qi)的(de)(de)控(kong)(kong)制，而控(kong)(kong)制的(de)(de)精度(du)和靈活性都能夠保證。電(dian)(dian)磁閥(fa)有很(hen)多種，不(bu)(bu)同(tong)的(de)(de)電(dian)(dian)磁閥(fa)在(zai)(zai)控(kong)(kong)制系(xi)統的(de)(de)不(bu)(bu)同(tong)位(wei)置發揮作用(yong)，最常用(yong)的(de)(de)是單向閥(fa)、安(an)全閥(fa)、方(fang)向控(kong)(kong)制閥(fa)、速度(du)調節閥(fa)等。

電(dian)磁(ci)(ci)閥里有密閉(bi)的(de)(de)腔，在不同(tong)(tong)位置(zhi)開有通(tong)(tong)孔(kong)，每個孔(kong)連接不同(tong)(tong)的(de)(de)油(you)(you)管，腔中間是(shi)活(huo)(huo)塞，兩面(mian)是(shi)兩塊(kuai)電(dian)磁(ci)(ci)鐵，哪面(mian)的(de)(de)磁(ci)(ci)鐵線圈通(tong)(tong)電(dian)閥體就(jiu)會被吸引到哪邊(bian)，通(tong)(tong)過控(kong)(kong)(kong)制(zhi)閥體的(de)(de)移動(dong)來(lai)(lai)開啟(qi)或關閉(bi)不同(tong)(tong)的(de)(de)排(pai)(pai)油(you)(you)孔(kong)，而進油(you)(you)孔(kong)是(shi)常開的(de)(de)，液壓油(you)(you)就(jiu)會進入不同(tong)(tong)的(de)(de)排(pai)(pai)油(you)(you)管，然后通(tong)(tong)過油(you)(you)的(de)(de)壓力來(lai)(lai)推(tui)動(dong)油(you)(you)缸的(de)(de)活(huo)(huo)塞，活(huo)(huo)塞又帶動(dong)活(huo)(huo)塞桿(gan)，活(huo)(huo)塞桿(gan)帶動(dong)機械裝置(zhi)。這(zhe)樣通(tong)(tong)過控(kong)(kong)(kong)制(zhi)電(dian)磁(ci)(ci)鐵的(de)(de)電(dian)流(liu)通(tong)(tong)斷就(jiu)控(kong)(kong)(kong)制(zhi)了機械運動(dong)。

1、電磁(ci)閥從(cong)原(yuan)理上分(fen)為三大類：

直動式電磁閥

原理：通電(dian)(dian)(dian)時，電(dian)(dian)(dian)磁線圈產生電(dian)(dian)(dian)磁力(li)把(ba)關(guan)閉件從閥座上(shang)提起(qi)，閥門(men)打開；斷電(dian)(dian)(dian)時，電(dian)(dian)(dian)磁力(li)消(xiao)失，彈簧(huang)把(ba)關(guan)閉件壓(ya)在閥座上(shang)，閥門(men)關(guan)閉。

特(te)點：在真空(kong)、負(fu)壓、零壓時能正常工作，但通(tong)徑一般不超過25mm。

分步直動式(shi)電磁閥

原(yuan)理：它(ta)是(shi)一種直動(dong)和(he)先(xian)(xian)導式相結(jie)合的原(yuan)理，當入口與出(chu)口沒有壓(ya)(ya)(ya)差時(shi)，通電(dian)(dian)后(hou)，電(dian)(dian)磁力(li)直接把先(xian)(xian)導小(xiao)閥(fa)(fa)(fa)和(he)主閥(fa)(fa)(fa)關(guan)閉件(jian)依次向上提起，閥(fa)(fa)(fa)門(men)打開(kai)。當入口與出(chu)口達到啟動(dong)壓(ya)(ya)(ya)差時(shi)，通電(dian)(dian)后(hou)，電(dian)(dian)磁力(li)先(xian)(xian)導小(xiao)閥(fa)(fa)(fa)，主閥(fa)(fa)(fa)下(xia)(xia)腔(qiang)壓(ya)(ya)(ya)力(li)上升，上腔(qiang)壓(ya)(ya)(ya)力(li)下(xia)(xia)降，從(cong)而利(li)用壓(ya)(ya)(ya)差把主閥(fa)(fa)(fa)向上推開(kai)；斷(duan)電(dian)(dian)時(shi)，先(xian)(xian)導閥(fa)(fa)(fa)利(li)用彈(dan)簧力(li)或介質壓(ya)(ya)(ya)力(li)推動(dong)關(guan)閉件(jian)，向下(xia)(xia)移動(dong)，使閥(fa)(fa)(fa)門(men)關(guan)閉。

特點：在零壓差或真空、高壓時亦能(neng)可*動作，但(dan)功(gong)率較大，要(yao)求必須水平安裝。

先導式電磁閥

原理：通電時(shi)(shi)，電磁(ci)力把(ba)先(xian)導孔(kong)(kong)打開，上(shang)腔室壓力迅(xun)速(su)下降(jiang)，在關(guan)(guan)(guan) 閉(bi)(bi)件(jian)周圍形成(cheng)上(shang)低下高的(de)壓差，流體壓力推動(dong)關(guan)(guan)(guan)閉(bi)(bi)件(jian)向上(shang)移動(dong)，閥(fa)門打開；斷(duan)電時(shi)(shi)，彈簧力把(ba)先(xian)導孔(kong)(kong)關(guan)(guan)(guan)閉(bi)(bi)，入口壓力通過(guo)旁通孔(kong)(kong)迅(xun)速(su)腔室在關(guan)(guan)(guan)閥(fa)件(jian)周圍形成(cheng)下低上(shang)高的(de)壓差，流體壓力推動(dong)關(guan)(guan)(guan)閉(bi)(bi)件(jian)向下移動(dong)，關(guan)(guan)(guan)閉(bi)(bi)閥(fa)門。

特點：流體壓(ya)力范圍(wei)上限較高，可任意(yi)安(an)裝（需定制）但必須滿足流體壓(ya)差條件。

2、電(dian)磁閥從(cong)閥結(jie)(jie)構(gou)(gou)和材料上的不同與原理上的區別(bie)，分為六個分支小類：直(zhi)動(dong)膜(mo)片(pian)結(jie)(jie)構(gou)(gou)、分步直(zhi)動(dong)膜(mo)片(pian)結(jie)(jie)構(gou)(gou)、先導(dao)膜(mo)片(pian)結(jie)(jie)構(gou)(gou)、直(zhi)動(dong)活塞結(jie)(jie)構(gou)(gou)、分步直(zhi)動(dong)活塞結(jie)(jie)構(gou)(gou)、先導(dao)活塞結(jie)(jie)構(gou)(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)按照功能分類：水用(yong)(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、制冷(leng)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、消防電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、氨用(yong)(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、氣(qi)體電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、液(ye)體電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、脈(mo)沖電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、液(ye)壓電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa) 常(chang)開電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、油用(yong)(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、防爆(bao)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)等。