電(dian)磁(ci)(ci)(ci)閥（Electromagnetic valve）是用(yong)電(dian)磁(ci)(ci)(ci)控制(zhi)的工(gong)(gong)業設備，是用(yong)來控制(zhi)流體(ti)的自動化基(ji)礎元件，屬于(yu)執行(xing)器，并不(bu)限于(yu)液壓、氣動。用(yong)在工(gong)(gong)業控制(zhi)系(xi)統(tong)中調整介質的方向、流量、速度和其(qi)他的參數。電(dian)磁(ci)(ci)(ci)閥可(ke)以配合不(bu)同(tong)(tong)的電(dian)路來實(shi)現預期(qi)的控制(zhi)，而控制(zhi)的精度和靈活性都能夠保證。電(dian)磁(ci)(ci)(ci)閥有很(hen)多(duo)種，不(bu)同(tong)(tong)的電(dian)磁(ci)(ci)(ci)閥在控制(zhi)系(xi)統(tong)的不(bu)同(tong)(tong)位置發揮作用(yong)，最常用(yong)的是單向閥、安全(quan)閥、方向控制(zhi)閥、速度調節閥等(deng)。

電磁(ci)閥(fa)里有密閉的(de)(de)腔(qiang)(qiang)，在不同(tong)位置(zhi)開(kai)有通(tong)孔(kong)，每個孔(kong)連接(jie)不同(tong)的(de)(de)油(you)管(guan)(guan)，腔(qiang)(qiang)中間是活塞(sai)，兩面是兩塊電磁(ci)鐵，哪面的(de)(de)磁(ci)鐵線圈通(tong)電閥(fa)體就會被吸引(yin)到(dao)哪邊，通(tong)過(guo)控制(zhi)閥(fa)體的(de)(de)移動(dong)(dong)來開(kai)啟或關閉不同(tong)的(de)(de)排(pai)油(you)孔(kong)，而進油(you)孔(kong)是常(chang)開(kai)的(de)(de)，液壓油(you)就會進入不同(tong)的(de)(de)排(pai)油(you)管(guan)(guan)，然后通(tong)過(guo)油(you)的(de)(de)壓力來推(tui)動(dong)(dong)油(you)缸的(de)(de)活塞(sai)，活塞(sai)又(you)帶動(dong)(dong)活塞(sai)桿(gan)，活塞(sai)桿(gan)帶動(dong)(dong)機械(xie)裝置(zhi)。這(zhe)樣通(tong)過(guo)控制(zhi)電磁(ci)鐵的(de)(de)電流通(tong)斷就控制(zhi)了(le)機械(xie)運動(dong)(dong)。

1、電(dian)磁閥從原理上分為三(san)大類：

直(zhi)動(dong)式電磁閥

原理：通電時，電磁線圈產生電磁力把(ba)關(guan)(guan)(guan)閉件從閥座(zuo)上提起，閥門(men)打(da)開；斷電時，電磁力消(xiao)失(shi)，彈(dan)簧把(ba)關(guan)(guan)(guan)閉件壓在閥座(zuo)上，閥門(men)關(guan)(guan)(guan)閉。

特點(dian)：在真空、負壓(ya)、零壓(ya)時(shi)能正(zheng)常工(gong)作(zuo)，但通徑一般不超過25mm。

分步直動式(shi)電磁閥(fa)

原理(li)：它是一(yi)種直動和(he)先(xian)導(dao)式(shi)相結合的(de)原理(li)，當(dang)入口(kou)與(yu)出(chu)口(kou)沒有壓差(cha)(cha)時，通電(dian)(dian)后，電(dian)(dian)磁力直接把(ba)先(xian)導(dao)小(xiao)閥(fa)和(he)主閥(fa)關閉(bi)件依次向(xiang)上(shang)(shang)提(ti)起，閥(fa)門打開(kai)。當(dang)入口(kou)與(yu)出(chu)口(kou)達到啟動壓差(cha)(cha)時，通電(dian)(dian)后，電(dian)(dian)磁力先(xian)導(dao)小(xiao)閥(fa)，主閥(fa)下(xia)腔壓力上(shang)(shang)升(sheng)，上(shang)(shang)腔壓力下(xia)降，從而利用(yong)壓差(cha)(cha)把(ba)主閥(fa)向(xiang)上(shang)(shang)推(tui)開(kai)；斷電(dian)(dian)時，先(xian)導(dao)閥(fa)利用(yong)彈簧力或介質壓力推(tui)動關閉(bi)件，向(xiang)下(xia)移動，使閥(fa)門關閉(bi)。

特點：在零壓差或真空、高壓時(shi)亦能可*動作，但功率較大，要求(qiu)必須水平安裝。

先(xian)導式(shi)電磁閥

原理：通(tong)電時，電磁力(li)(li)(li)(li)把先(xian)導孔(kong)(kong)打開(kai)，上(shang)腔(qiang)室(shi)壓(ya)力(li)(li)(li)(li)迅(xun)速(su)下降，在關(guan) 閉(bi)件(jian)周(zhou)圍形成上(shang)低下高的(de)壓(ya)差，流體(ti)壓(ya)力(li)(li)(li)(li)推動關(guan)閉(bi)件(jian)向上(shang)移(yi)動，閥(fa)門打開(kai)；斷(duan)電時，彈簧力(li)(li)(li)(li)把先(xian)導孔(kong)(kong)關(guan)閉(bi)，入口壓(ya)力(li)(li)(li)(li)通(tong)過旁通(tong)孔(kong)(kong)迅(xun)速(su)腔(qiang)室(shi)在關(guan)閥(fa)件(jian)周(zhou)圍形成下低上(shang)高的(de)壓(ya)差，流體(ti)壓(ya)力(li)(li)(li)(li)推動關(guan)閉(bi)件(jian)向下移(yi)動，關(guan)閉(bi)閥(fa)門。

特(te)點：流體(ti)壓力(li)范圍上限較高，可任意安(an)裝（需定(ding)制）但必須滿(man)足流體(ti)壓差條件。

2、電磁(ci)閥從閥結(jie)構(gou)(gou)(gou)和材料(liao)上的不同與原(yuan)理上的區(qu)別，分為六個分支小類(lei)：直動(dong)膜(mo)片結(jie)構(gou)(gou)(gou)、分步(bu)直動(dong)膜(mo)片結(jie)構(gou)(gou)(gou)、先(xian)導(dao)(dao)膜(mo)片結(jie)構(gou)(gou)(gou)、直動(dong)活(huo)(huo)塞結(jie)構(gou)(gou)(gou)、分步(bu)直動(dong)活(huo)(huo)塞結(jie)構(gou)(gou)(gou)、先(xian)導(dao)(dao)活(huo)(huo)塞結(jie)構(gou)(gou)(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)按照功能分類：水(shui)用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、制冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、低溫(wen)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、消(xiao)防電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、氨用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、氣體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、液(ye)體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、微型電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、液(ye)壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、油用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、直(zhi)流電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、高壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)、防爆(bao)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)等。