電(dian)磁閥(fa)（Electromagnetic valve）是用(yong)電(dian)磁控制(zhi)(zhi)(zhi)的(de)工業(ye)設備，是用(yong)來(lai)(lai)控制(zhi)(zhi)(zhi)流體的(de)自動化基礎元件(jian)，屬(shu)于(yu)執行(xing)器，并不(bu)限于(yu)液壓(ya)、氣動。用(yong)在(zai)工業(ye)控制(zhi)(zhi)(zhi)系統中調整介質(zhi)的(de)方(fang)向、流量、速(su)度和其他的(de)參數。電(dian)磁閥(fa)可以(yi)配合不(bu)同的(de)電(dian)路來(lai)(lai)實現(xian)預期(qi)的(de)控制(zhi)(zhi)(zhi)，而控制(zhi)(zhi)(zhi)的(de)精度和靈活性都能(neng)夠保證。電(dian)磁閥(fa)有很多種，不(bu)同的(de)電(dian)磁閥(fa)在(zai)控制(zhi)(zhi)(zhi)系統的(de)不(bu)同位(wei)置發揮作用(yong)，最常用(yong)的(de)是單向閥(fa)、安全閥(fa)、方(fang)向控制(zhi)(zhi)(zhi)閥(fa)、速(su)度調節閥(fa)等。

電(dian)磁閥(fa)里有密閉的(de)(de)腔，在不(bu)同(tong)(tong)(tong)位置(zhi)開有通(tong)孔(kong)，每個(ge)孔(kong)連接不(bu)同(tong)(tong)(tong)的(de)(de)油(you)(you)管，腔中間是(shi)活塞(sai)，兩面(mian)是(shi)兩塊電(dian)磁鐵(tie)，哪面(mian)的(de)(de)磁鐵(tie)線圈通(tong)電(dian)閥(fa)體(ti)就(jiu)會(hui)被吸引到哪邊，通(tong)過(guo)控制閥(fa)體(ti)的(de)(de)移動(dong)來(lai)開啟或關閉不(bu)同(tong)(tong)(tong)的(de)(de)排油(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(hui)進入不(bu)同(tong)(tong)(tong)的(de)(de)排油(you)(you)管，然后通(tong)過(guo)油(you)(you)的(de)(de)壓力來(lai)推動(dong)油(you)(you)缸的(de)(de)活塞(sai)，活塞(sai)又帶動(dong)活塞(sai)桿(gan)，活塞(sai)桿(gan)帶動(dong)機械裝置(zhi)。這樣通(tong)過(guo)控制電(dian)磁鐵(tie)的(de)(de)電(dian)流通(tong)斷就(jiu)控制了機械運動(dong)。

1、電(dian)磁閥從(cong)原理上分為三大類(lei)：

直動式電磁閥

原理：通電(dian)時，電(dian)磁(ci)線(xian)圈產生電(dian)磁(ci)力把(ba)關閉件從閥(fa)座上提起，閥(fa)門(men)打開(kai)；斷電(dian)時，電(dian)磁(ci)力消失，彈簧把(ba)關閉件壓在(zai)閥(fa)座上，閥(fa)門(men)關閉。

特點：在真空、負壓、零(ling)壓時能正常工作，但通徑一(yi)般不超過25mm。

分步直動(dong)式電磁(ci)閥

原(yuan)理：它是(shi)一種直動(dong)和先導(dao)式相結合的原(yuan)理，當(dang)入(ru)口(kou)與(yu)(yu)出口(kou)沒有(you)壓(ya)(ya)差時(shi)，通電(dian)后(hou)，電(dian)磁(ci)力(li)(li)直接把先導(dao)小閥(fa)(fa)和主閥(fa)(fa)關(guan)(guan)(guan)閉件依次(ci)向(xiang)上提起(qi)，閥(fa)(fa)門(men)打開。當(dang)入(ru)口(kou)與(yu)(yu)出口(kou)達(da)到啟動(dong)壓(ya)(ya)差時(shi)，通電(dian)后(hou)，電(dian)磁(ci)力(li)(li)先導(dao)小閥(fa)(fa)，主閥(fa)(fa)下(xia)腔(qiang)壓(ya)(ya)力(li)(li)上升，上腔(qiang)壓(ya)(ya)力(li)(li)下(xia)降，從而利用壓(ya)(ya)差把主閥(fa)(fa)向(xiang)上推開；斷電(dian)時(shi)，先導(dao)閥(fa)(fa)利用彈簧力(li)(li)或介質壓(ya)(ya)力(li)(li)推動(dong)關(guan)(guan)(guan)閉件，向(xiang)下(xia)移動(dong)，使閥(fa)(fa)門(men)關(guan)(guan)(guan)閉。

特點：在零壓(ya)差或真空、高壓(ya)時亦能可*動作(zuo)，但功(gong)率較大，要求必須水平安裝。

先導式電磁(ci)閥

原(yuan)理：通電時，電磁(ci)力(li)(li)把(ba)先(xian)導孔打開，上腔(qiang)室壓(ya)(ya)(ya)力(li)(li)迅速(su)下(xia)降，在(zai)(zai)關(guan) 閉件(jian)周圍形(xing)成上低下(xia)高的壓(ya)(ya)(ya)差，流體壓(ya)(ya)(ya)力(li)(li)推動(dong)關(guan)閉件(jian)向上移動(dong)，閥(fa)門(men)打開；斷電時，彈(dan)簧力(li)(li)把(ba)先(xian)導孔關(guan)閉，入口壓(ya)(ya)(ya)力(li)(li)通過(guo)旁(pang)通孔迅速(su)腔(qiang)室在(zai)(zai)關(guan)閥(fa)件(jian)周圍形(xing)成下(xia)低上高的壓(ya)(ya)(ya)差，流體壓(ya)(ya)(ya)力(li)(li)推動(dong)關(guan)閉件(jian)向下(xia)移動(dong)，關(guan)閉閥(fa)門(men)。

特點：流(liu)體(ti)(ti)壓力范圍上限較高，可(ke)任(ren)意安裝(zhuang)（需定制）但必須滿足(zu)流(liu)體(ti)(ti)壓差(cha)條(tiao)件。

2、電磁閥從閥結構(gou)(gou)(gou)(gou)和材料(liao)上的不同與原理上的區別，分(fen)為(wei)六個分(fen)支小類：直動膜片(pian)結構(gou)(gou)(gou)(gou)、分(fen)步直動膜片(pian)結構(gou)(gou)(gou)(gou)、先導膜片(pian)結構(gou)(gou)(gou)(gou)、直動活塞結構(gou)(gou)(gou)(gou)、分(fen)步直動活塞結構(gou)(gou)(gou)(gou)、先導活塞結構(gou)(gou)(gou)(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)按照功(gong)能分(fen)類：水用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、制冷(leng)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、低(di)溫電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、氨用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、氣體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、液體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、微型電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、液壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、油用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、直流電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、高壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)、防(fang)爆電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)等。