電磁(ci)閥(fa)（Electromagnetic valve）是(shi)(shi)用電磁(ci)控(kong)制(zhi)的(de)(de)(de)(de)工業(ye)設備，是(shi)(shi)用來(lai)控(kong)制(zhi)流體的(de)(de)(de)(de)自(zi)動化基礎元件，屬(shu)于執行器，并不(bu)(bu)(bu)限于液壓、氣動。用在(zai)工業(ye)控(kong)制(zhi)系統中調(diao)整介質的(de)(de)(de)(de)方向、流量、速(su)度(du)(du)和其(qi)他的(de)(de)(de)(de)參數。電磁(ci)閥(fa)可以配合不(bu)(bu)(bu)同的(de)(de)(de)(de)電路來(lai)實現預期的(de)(de)(de)(de)控(kong)制(zhi)，而控(kong)制(zhi)的(de)(de)(de)(de)精度(du)(du)和靈活性都能夠保證。電磁(ci)閥(fa)有很多(duo)種(zhong)，不(bu)(bu)(bu)同的(de)(de)(de)(de)電磁(ci)閥(fa)在(zai)控(kong)制(zhi)系統的(de)(de)(de)(de)不(bu)(bu)(bu)同位置發揮作用，最常(chang)用的(de)(de)(de)(de)是(shi)(shi)單(dan)向閥(fa)、安全閥(fa)、方向控(kong)制(zhi)閥(fa)、速(su)度(du)(du)調(diao)節閥(fa)等。

電(dian)磁閥(fa)里有密閉的(de)(de)(de)(de)腔，在不(bu)(bu)同(tong)位(wei)置開(kai)有通(tong)(tong)孔，每個孔連接不(bu)(bu)同(tong)的(de)(de)(de)(de)油(you)(you)(you)管，腔中間(jian)是活塞(sai)(sai)，兩面(mian)是兩塊電(dian)磁鐵，哪面(mian)的(de)(de)(de)(de)磁鐵線圈(quan)通(tong)(tong)電(dian)閥(fa)體(ti)就會被(bei)吸引到(dao)哪邊，通(tong)(tong)過(guo)控制(zhi)閥(fa)體(ti)的(de)(de)(de)(de)移動(dong)來開(kai)啟(qi)或(huo)關(guan)閉不(bu)(bu)同(tong)的(de)(de)(de)(de)排油(you)(you)(you)孔，而進(jin)油(you)(you)(you)孔是常開(kai)的(de)(de)(de)(de)，液壓油(you)(you)(you)就會進(jin)入不(bu)(bu)同(tong)的(de)(de)(de)(de)排油(you)(you)(you)管，然(ran)后通(tong)(tong)過(guo)油(you)(you)(you)的(de)(de)(de)(de)壓力來推(tui)動(dong)油(you)(you)(you)缸(gang)的(de)(de)(de)(de)活塞(sai)(sai)，活塞(sai)(sai)又帶動(dong)活塞(sai)(sai)桿，活塞(sai)(sai)桿帶動(dong)機(ji)械裝置。這樣通(tong)(tong)過(guo)控制(zhi)電(dian)磁鐵的(de)(de)(de)(de)電(dian)流(liu)通(tong)(tong)斷就控制(zhi)了機(ji)械運動(dong)。

1、電磁閥(fa)從原理上分為三(san)大類：

直動式(shi)電(dian)磁閥(fa)

原理：通電(dian)(dian)時，電(dian)(dian)磁線圈產生電(dian)(dian)磁力(li)把關(guan)(guan)閉件(jian)從閥座上提(ti)起，閥門(men)打開；斷(duan)電(dian)(dian)時，電(dian)(dian)磁力(li)消失，彈簧把關(guan)(guan)閉件(jian)壓在閥座上，閥門(men)關(guan)(guan)閉。

特點：在(zai)真(zhen)空、負壓(ya)、零壓(ya)時能正常(chang)工作，但通徑一般不超過25mm。

分(fen)步直(zhi)動式電磁閥

原(yuan)(yuan)理：它是一種直(zhi)動和先(xian)(xian)導式相結合的原(yuan)(yuan)理，當入(ru)口與出口沒有壓(ya)(ya)差(cha)時(shi)，通電(dian)后，電(dian)磁(ci)力直(zhi)接把先(xian)(xian)導小閥和主閥關閉件依次向(xiang)(xiang)上(shang)提起，閥門打開(kai)。當入(ru)口與出口達到啟動壓(ya)(ya)差(cha)時(shi)，通電(dian)后，電(dian)磁(ci)力先(xian)(xian)導小閥，主閥下腔(qiang)壓(ya)(ya)力上(shang)升(sheng)，上(shang)腔(qiang)壓(ya)(ya)力下降，從而利(li)(li)用壓(ya)(ya)差(cha)把主閥向(xiang)(xiang)上(shang)推開(kai)；斷(duan)電(dian)時(shi)，先(xian)(xian)導閥利(li)(li)用彈簧力或介質壓(ya)(ya)力推動關閉件，向(xiang)(xiang)下移動，使閥門關閉。

特(te)點(dian)：在零壓差(cha)或真空、高壓時亦能可(ke)*動作，但功率較大，要求必須水平(ping)安裝。

先(xian)導式電磁閥

原理：通(tong)(tong)電時，電磁力(li)(li)(li)把(ba)先導(dao)孔打開，上腔室壓(ya)(ya)力(li)(li)(li)迅速(su)下降，在(zai)關(guan) 閉件(jian)周圍形成上低下高的壓(ya)(ya)差，流體壓(ya)(ya)力(li)(li)(li)推(tui)(tui)動關(guan)閉件(jian)向上移動，閥門打開；斷電時，彈簧力(li)(li)(li)把(ba)先導(dao)孔關(guan)閉，入(ru)口壓(ya)(ya)力(li)(li)(li)通(tong)(tong)過旁(pang)通(tong)(tong)孔迅速(su)腔室在(zai)關(guan)閥件(jian)周圍形成下低上高的壓(ya)(ya)差，流體壓(ya)(ya)力(li)(li)(li)推(tui)(tui)動關(guan)閉件(jian)向下移動，關(guan)閉閥門。

特點：流體壓力范圍上限較高(gao)，可任意(yi)安裝（需定制(zhi)）但必須(xu)滿足流體壓差條(tiao)件。

2、電磁(ci)閥從閥結(jie)構(gou)和材料上(shang)(shang)的(de)不同與原(yuan)理上(shang)(shang)的(de)區別，分(fen)為六個(ge)分(fen)支(zhi)小類：直動膜片(pian)結(jie)構(gou)、分(fen)步(bu)直動膜片(pian)結(jie)構(gou)、先(xian)導膜片(pian)結(jie)構(gou)、直動活(huo)塞(sai)(sai)結(jie)構(gou)、分(fen)步(bu)直動活(huo)塞(sai)(sai)結(jie)構(gou)、先(xian)導活(huo)塞(sai)(sai)結(jie)構(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)按照(zhao)功能分(fen)類：水用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、消防電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、氨(an)用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、氣(qi)體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、液(ye)體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、微(wei)型(xing)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、液(ye)壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、油用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、直流(liu)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、高壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、防爆電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)等。