電(dian)磁(ci)閥(fa)（Electromagnetic valve）是用(yong)電(dian)磁(ci)控(kong)制(zhi)(zhi)的(de)(de)工業設(she)備，是用(yong)來(lai)控(kong)制(zhi)(zhi)流體的(de)(de)自動化基礎元件(jian)，屬于(yu)執行(xing)器，并不(bu)(bu)限于(yu)液壓(ya)、氣動。用(yong)在(zai)工業控(kong)制(zhi)(zhi)系統中(zhong)調整介質的(de)(de)方向、流量、速(su)度(du)和其(qi)他的(de)(de)參數。電(dian)磁(ci)閥(fa)可以(yi)配合不(bu)(bu)同(tong)的(de)(de)電(dian)路(lu)來(lai)實現預期的(de)(de)控(kong)制(zhi)(zhi)，而控(kong)制(zhi)(zhi)的(de)(de)精(jing)度(du)和靈活性都能夠(gou)保證。電(dian)磁(ci)閥(fa)有很多種，不(bu)(bu)同(tong)的(de)(de)電(dian)磁(ci)閥(fa)在(zai)控(kong)制(zhi)(zhi)系統的(de)(de)不(bu)(bu)同(tong)位(wei)置發(fa)揮(hui)作(zuo)用(yong)，最常用(yong)的(de)(de)是單向閥(fa)、安全閥(fa)、方向控(kong)制(zhi)(zhi)閥(fa)、速(su)度(du)調節閥(fa)等(deng)。

電(dian)磁閥(fa)里有密(mi)閉的腔(qiang)，在不(bu)同(tong)位(wei)置開有通(tong)孔，每個孔連接不(bu)同(tong)的油(you)管，腔(qiang)中(zhong)間是活(huo)塞，兩面是兩塊電(dian)磁鐵，哪面的磁鐵線(xian)圈通(tong)電(dian)閥(fa)體(ti)就會被吸(xi)引到哪邊，通(tong)過(guo)控(kong)制閥(fa)體(ti)的移動(dong)來開啟或關閉不(bu)同(tong)的排油(you)孔，而(er)進油(you)孔是常開的，液壓(ya)油(you)就會進入不(bu)同(tong)的排油(you)管，然后(hou)通(tong)過(guo)油(you)的壓(ya)力來推動(dong)油(you)缸的活(huo)塞，活(huo)塞又帶動(dong)活(huo)塞桿，活(huo)塞桿帶動(dong)機(ji)械裝置。這(zhe)樣通(tong)過(guo)控(kong)制電(dian)磁鐵的電(dian)流通(tong)斷就控(kong)制了機(ji)械運動(dong)。

1、電磁閥(fa)從原理上分為三大類：

直(zhi)動式電(dian)磁閥

原(yuan)理：通電(dian)(dian)時，電(dian)(dian)磁(ci)線(xian)圈產生電(dian)(dian)磁(ci)力(li)把關閉件(jian)從閥(fa)座(zuo)上提起，閥(fa)門(men)打(da)開；斷電(dian)(dian)時，電(dian)(dian)磁(ci)力(li)消失(shi)，彈簧把關閉件(jian)壓在閥(fa)座(zuo)上，閥(fa)門(men)關閉。

特(te)點：在真空、負壓、零(ling)壓時(shi)能正常工作(zuo)，但通徑(jing)一般不超過25mm。

分(fen)步(bu)直動式電磁閥

原(yuan)理：它(ta)是一種直(zhi)動(dong)(dong)和先導(dao)式(shi)相結合的原(yuan)理，當入(ru)口(kou)與出口(kou)沒有壓(ya)(ya)差時(shi)，通電(dian)后，電(dian)磁(ci)(ci)力直(zhi)接把先導(dao)小(xiao)閥(fa)(fa)(fa)和主(zhu)閥(fa)(fa)(fa)關(guan)(guan)閉件依次(ci)向上(shang)提起，閥(fa)(fa)(fa)門打開(kai)。當入(ru)口(kou)與出口(kou)達(da)到啟動(dong)(dong)壓(ya)(ya)差時(shi)，通電(dian)后，電(dian)磁(ci)(ci)力先導(dao)小(xiao)閥(fa)(fa)(fa)，主(zhu)閥(fa)(fa)(fa)下腔壓(ya)(ya)力上(shang)升，上(shang)腔壓(ya)(ya)力下降，從而利用壓(ya)(ya)差把主(zhu)閥(fa)(fa)(fa)向上(shang)推開(kai)；斷電(dian)時(shi)，先導(dao)閥(fa)(fa)(fa)利用彈簧力或介質壓(ya)(ya)力推動(dong)(dong)關(guan)(guan)閉件，向下移動(dong)(dong)，使閥(fa)(fa)(fa)門關(guan)(guan)閉。

特點：在(zai)零壓差或真空、高壓時亦能可*動作，但功率較大，要求(qiu)必須水平安裝。

先導式電(dian)磁閥

原理：通電(dian)(dian)時(shi)，電(dian)(dian)磁(ci)力把(ba)先導孔打(da)(da)開，上(shang)腔室壓力迅(xun)速下降，在(zai)關(guan)(guan)(guan) 閉(bi)(bi)件周(zhou)圍(wei)形成上(shang)低下高的壓差(cha)，流體壓力推動(dong)關(guan)(guan)(guan)閉(bi)(bi)件向上(shang)移(yi)動(dong)，閥(fa)門(men)打(da)(da)開；斷電(dian)(dian)時(shi)，彈簧力把(ba)先導孔關(guan)(guan)(guan)閉(bi)(bi)，入口壓力通過旁通孔迅(xun)速腔室在(zai)關(guan)(guan)(guan)閥(fa)件周(zhou)圍(wei)形成下低上(shang)高的壓差(cha)，流體壓力推動(dong)關(guan)(guan)(guan)閉(bi)(bi)件向下移(yi)動(dong)，關(guan)(guan)(guan)閉(bi)(bi)閥(fa)門(men)。

特點：流體壓力范(fan)圍(wei)上(shang)限較高，可任意安裝（需定制）但必須滿足流體壓差條件。

2、電磁閥從閥結構(gou)(gou)和(he)材料上(shang)(shang)的不同(tong)與(yu)原(yuan)理(li)上(shang)(shang)的區(qu)別，分為六個分支小類：直動(dong)膜(mo)片結構(gou)(gou)、分步直動(dong)膜(mo)片結構(gou)(gou)、先(xian)導(dao)膜(mo)片結構(gou)(gou)、直動(dong)活塞結構(gou)(gou)、分步直動(dong)活塞結構(gou)(gou)、先(xian)導(dao)活塞結構(gou)(gou)。

3、電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)按(an)照功(gong)能(neng)分類：水用電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、蒸汽電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、制冷電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、低溫(wen)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、燃(ran)氣(qi)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、消防電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、氨用電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、氣(qi)體電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、液體電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、微型(xing)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、脈沖電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、液壓(ya)(ya)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa) 常開電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、油(you)用電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、直流電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、高壓(ya)(ya)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)、防爆電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)等。