電(dian)磁閥(fa)（Electromagnetic valve）是用(yong)(yong)電(dian)磁控(kong)(kong)制(zhi)(zhi)的(de)(de)(de)工業(ye)設備，是用(yong)(yong)來控(kong)(kong)制(zhi)(zhi)流體的(de)(de)(de)自動(dong)化基礎(chu)元件，屬于執行器，并不(bu)限于液壓(ya)、氣動(dong)。用(yong)(yong)在工業(ye)控(kong)(kong)制(zhi)(zhi)系統中調整介質的(de)(de)(de)方向、流量(liang)、速度和(he)其(qi)他的(de)(de)(de)參數。電(dian)磁閥(fa)可(ke)以配合(he)不(bu)同的(de)(de)(de)電(dian)路(lu)來實現預期(qi)的(de)(de)(de)控(kong)(kong)制(zhi)(zhi)，而控(kong)(kong)制(zhi)(zhi)的(de)(de)(de)精度和(he)靈活性都能夠保證。電(dian)磁閥(fa)有很多種，不(bu)同的(de)(de)(de)電(dian)磁閥(fa)在控(kong)(kong)制(zhi)(zhi)系統的(de)(de)(de)不(bu)同位置發揮(hui)作用(yong)(yong)，最常用(yong)(yong)的(de)(de)(de)是單(dan)向閥(fa)、安全閥(fa)、方向控(kong)(kong)制(zhi)(zhi)閥(fa)、速度調節閥(fa)等。

電(dian)(dian)磁閥(fa)里有密閉的(de)(de)(de)(de)(de)(de)腔(qiang)，在不同(tong)位置(zhi)開(kai)(kai)有通(tong)孔(kong)，每個孔(kong)連(lian)接(jie)不同(tong)的(de)(de)(de)(de)(de)(de)油(you)(you)管(guan)，腔(qiang)中(zhong)間是(shi)活(huo)(huo)塞(sai)，兩面是(shi)兩塊電(dian)(dian)磁鐵，哪面的(de)(de)(de)(de)(de)(de)磁鐵線(xian)圈通(tong)電(dian)(dian)閥(fa)體就(jiu)會被吸引(yin)到(dao)哪邊(bian)，通(tong)過(guo)控(kong)制閥(fa)體的(de)(de)(de)(de)(de)(de)移動來開(kai)(kai)啟(qi)或關閉不同(tong)的(de)(de)(de)(de)(de)(de)排(pai)油(you)(you)孔(kong)，而(er)進油(you)(you)孔(kong)是(shi)常(chang)開(kai)(kai)的(de)(de)(de)(de)(de)(de)，液壓(ya)油(you)(you)就(jiu)會進入(ru)不同(tong)的(de)(de)(de)(de)(de)(de)排(pai)油(you)(you)管(guan)，然后通(tong)過(guo)油(you)(you)的(de)(de)(de)(de)(de)(de)壓(ya)力來推動油(you)(you)缸的(de)(de)(de)(de)(de)(de)活(huo)(huo)塞(sai)，活(huo)(huo)塞(sai)又帶動活(huo)(huo)塞(sai)桿，活(huo)(huo)塞(sai)桿帶動機(ji)(ji)械裝置(zhi)。這樣通(tong)過(guo)控(kong)制電(dian)(dian)磁鐵的(de)(de)(de)(de)(de)(de)電(dian)(dian)流(liu)通(tong)斷就(jiu)控(kong)制了機(ji)(ji)械運(yun)動。

1、電磁閥從(cong)原理上分為三(san)大(da)類：

直動式電磁(ci)閥

原(yuan)理：通電(dian)(dian)時(shi)，電(dian)(dian)磁(ci)(ci)線圈產生(sheng)電(dian)(dian)磁(ci)(ci)力把關(guan)閉(bi)件從(cong)閥(fa)(fa)(fa)座上提起，閥(fa)(fa)(fa)門(men)(men)打(da)開；斷電(dian)(dian)時(shi)，電(dian)(dian)磁(ci)(ci)力消失(shi)，彈簧把關(guan)閉(bi)件壓(ya)在(zai)閥(fa)(fa)(fa)座上，閥(fa)(fa)(fa)門(men)(men)關(guan)閉(bi)。

特點：在真空、負壓、零壓時能正常(chang)工作，但通(tong)徑一般不超過25mm。

分步直動式電磁(ci)閥

原理(li)：它是一種(zhong)直(zhi)動和先(xian)(xian)導式相結合的原理(li)，當入口(kou)與(yu)出口(kou)沒有(you)壓差(cha)(cha)時，通(tong)電(dian)后，電(dian)磁(ci)力(li)直(zhi)接把先(xian)(xian)導小閥(fa)和主(zhu)閥(fa)關(guan)閉(bi)(bi)件依次向上(shang)提起(qi)，閥(fa)門打開。當入口(kou)與(yu)出口(kou)達到啟動壓差(cha)(cha)時，通(tong)電(dian)后，電(dian)磁(ci)力(li)先(xian)(xian)導小閥(fa)，主(zhu)閥(fa)下腔壓力(li)上(shang)升，上(shang)腔壓力(li)下降，從(cong)而利用壓差(cha)(cha)把主(zhu)閥(fa)向上(shang)推(tui)開；斷電(dian)時，先(xian)(xian)導閥(fa)利用彈簧力(li)或(huo)介(jie)質(zhi)壓力(li)推(tui)動關(guan)閉(bi)(bi)件，向下移動，使閥(fa)門關(guan)閉(bi)(bi)。

特點：在零壓(ya)差或(huo)真空、高(gao)壓(ya)時亦(yi)能可*動作，但功率(lv)較大，要求必須水平安裝。

先導式電磁閥(fa)

原理(li)：通電(dian)時，電(dian)磁(ci)力(li)把先導(dao)孔打開，上腔(qiang)室壓力(li)迅速下(xia)降，在(zai)關(guan) 閉(bi)(bi)件周(zhou)(zhou)圍形成上低(di)下(xia)高的(de)壓差，流體(ti)壓力(li)推動(dong)關(guan)閉(bi)(bi)件向上移動(dong)，閥(fa)門打開；斷(duan)電(dian)時，彈(dan)簧(huang)力(li)把先導(dao)孔關(guan)閉(bi)(bi)，入(ru)口壓力(li)通過旁通孔迅速腔(qiang)室在(zai)關(guan)閥(fa)件周(zhou)(zhou)圍形成下(xia)低(di)上高的(de)壓差，流體(ti)壓力(li)推動(dong)關(guan)閉(bi)(bi)件向下(xia)移動(dong)，關(guan)閉(bi)(bi)閥(fa)門。

特點(dian)：流體(ti)壓力范圍(wei)上限較高，可任(ren)意安裝（需定制）但必(bi)須滿足(zu)流體(ti)壓差條件。

2、電磁閥(fa)從閥(fa)結(jie)(jie)(jie)構和材料(liao)上的不同與原理上的區(qu)別，分為六個分支小類：直動(dong)膜(mo)片(pian)結(jie)(jie)(jie)構、分步(bu)直動(dong)膜(mo)片(pian)結(jie)(jie)(jie)構、先(xian)導(dao)膜(mo)片(pian)結(jie)(jie)(jie)構、直動(dong)活塞(sai)結(jie)(jie)(jie)構、分步(bu)直動(dong)活塞(sai)結(jie)(jie)(jie)構、先(xian)導(dao)活塞(sai)結(jie)(jie)(jie)構。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)按照功能分類：水用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、制冷(leng)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、低溫電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、氨用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、氣(qi)體(ti)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、液體(ti)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、微(wei)型電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、液壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、油(you)用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、直流電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、高壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)、防(fang)爆電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)等(deng)。