電磁閥(fa)(fa)（Electromagnetic valve）是(shi)用(yong)(yong)電磁控(kong)(kong)(kong)制的(de)工(gong)業(ye)設備，是(shi)用(yong)(yong)來(lai)控(kong)(kong)(kong)制流(liu)體的(de)自動化基礎元(yuan)件，屬(shu)于(yu)執行器，并不限于(yu)液壓、氣動。用(yong)(yong)在工(gong)業(ye)控(kong)(kong)(kong)制系統中調(diao)整介(jie)質(zhi)的(de)方向、流(liu)量、速(su)度(du)(du)(du)和其他(ta)的(de)參(can)數。電磁閥(fa)(fa)可以配合不同的(de)電路來(lai)實現(xian)預期的(de)控(kong)(kong)(kong)制，而(er)控(kong)(kong)(kong)制的(de)精度(du)(du)(du)和靈活性都能(neng)夠保證。電磁閥(fa)(fa)有很多種，不同的(de)電磁閥(fa)(fa)在控(kong)(kong)(kong)制系統的(de)不同位置發揮(hui)作用(yong)(yong)，最常用(yong)(yong)的(de)是(shi)單向閥(fa)(fa)、安全閥(fa)(fa)、方向控(kong)(kong)(kong)制閥(fa)(fa)、速(su)度(du)(du)(du)調(diao)節(jie)閥(fa)(fa)等(deng)。

電磁閥(fa)(fa)里有密閉的(de)(de)腔(qiang)，在不(bu)同位置(zhi)開有通(tong)(tong)(tong)(tong)孔，每個孔連接不(bu)同的(de)(de)油(you)管，腔(qiang)中間是活塞，兩面是兩塊電磁鐵，哪面的(de)(de)磁鐵線圈通(tong)(tong)(tong)(tong)電閥(fa)(fa)體就(jiu)(jiu)會被吸引到(dao)哪邊，通(tong)(tong)(tong)(tong)過(guo)控制(zhi)(zhi)閥(fa)(fa)體的(de)(de)移動(dong)來開啟或關閉不(bu)同的(de)(de)排(pai)油(you)孔，而進油(you)孔是常開的(de)(de)，液(ye)壓油(you)就(jiu)(jiu)會進入不(bu)同的(de)(de)排(pai)油(you)管，然后通(tong)(tong)(tong)(tong)過(guo)油(you)的(de)(de)壓力來推動(dong)油(you)缸(gang)的(de)(de)活塞，活塞又帶(dai)動(dong)活塞桿，活塞桿帶(dai)動(dong)機(ji)械(xie)裝(zhuang)置(zhi)。這樣(yang)通(tong)(tong)(tong)(tong)過(guo)控制(zhi)(zhi)電磁鐵的(de)(de)電流通(tong)(tong)(tong)(tong)斷就(jiu)(jiu)控制(zhi)(zhi)了(le)機(ji)械(xie)運動(dong)。

1、電磁閥從(cong)原(yuan)理上分為三大(da)類：

直(zhi)動(dong)式電(dian)磁閥

原理：通電時，電磁(ci)線圈產生電磁(ci)力把關(guan)(guan)(guan)閉件從閥座上提起，閥門(men)打開；斷電時，電磁(ci)力消失(shi)，彈簧把關(guan)(guan)(guan)閉件壓在閥座上，閥門(men)關(guan)(guan)(guan)閉。

特點：在(zai)真空、負壓(ya)、零壓(ya)時能正常工作(zuo)，但通徑(jing)一般不(bu)超(chao)過25mm。

分步直動式電磁閥

原(yuan)理(li)：它(ta)是一(yi)種直動和先(xian)導(dao)式相結合(he)的原(yuan)理(li)，當入口(kou)與出口(kou)沒(mei)有壓(ya)(ya)差(cha)時，通電(dian)(dian)后，電(dian)(dian)磁力(li)直接把先(xian)導(dao)小閥(fa)和主閥(fa)關閉(bi)件(jian)依次向(xiang)上(shang)提起，閥(fa)門打開。當入口(kou)與出口(kou)達(da)到啟動壓(ya)(ya)差(cha)時，通電(dian)(dian)后，電(dian)(dian)磁力(li)先(xian)導(dao)小閥(fa)，主閥(fa)下(xia)腔(qiang)壓(ya)(ya)力(li)上(shang)升，上(shang)腔(qiang)壓(ya)(ya)力(li)下(xia)降，從(cong)而利用(yong)壓(ya)(ya)差(cha)把主閥(fa)向(xiang)上(shang)推(tui)開；斷電(dian)(dian)時，先(xian)導(dao)閥(fa)利用(yong)彈簧力(li)或介質壓(ya)(ya)力(li)推(tui)動關閉(bi)件(jian)，向(xiang)下(xia)移動，使(shi)閥(fa)門關閉(bi)。

特點：在零壓(ya)差或真空(kong)、高(gao)壓(ya)時亦能可*動作，但功率較大，要求(qiu)必須水平安裝。

先導式(shi)電磁閥(fa)

原理：通電時，電磁力(li)(li)(li)(li)把(ba)先導孔(kong)打開(kai)，上(shang)腔室壓(ya)(ya)力(li)(li)(li)(li)迅(xun)(xun)速下(xia)降，在關(guan) 閉(bi)件周圍形成上(shang)低下(xia)高(gao)的(de)壓(ya)(ya)差，流(liu)體壓(ya)(ya)力(li)(li)(li)(li)推動(dong)(dong)關(guan)閉(bi)件向上(shang)移(yi)動(dong)(dong)，閥門打開(kai)；斷電時，彈簧力(li)(li)(li)(li)把(ba)先導孔(kong)關(guan)閉(bi)，入口壓(ya)(ya)力(li)(li)(li)(li)通過旁(pang)通孔(kong)迅(xun)(xun)速腔室在關(guan)閥件周圍形成下(xia)低上(shang)高(gao)的(de)壓(ya)(ya)差，流(liu)體壓(ya)(ya)力(li)(li)(li)(li)推動(dong)(dong)關(guan)閉(bi)件向下(xia)移(yi)動(dong)(dong)，關(guan)閉(bi)閥門。

特點(dian)：流(liu)(liu)體壓(ya)力范圍上限較高，可任意安裝（需定制）但必須(xu)滿足流(liu)(liu)體壓(ya)差條(tiao)件。

2、電磁閥從閥結構(gou)和材(cai)料(liao)上(shang)的不同與原理上(shang)的區別，分為六(liu)個分支小類(lei)：直動(dong)膜(mo)片(pian)結構(gou)、分步直動(dong)膜(mo)片(pian)結構(gou)、先導膜(mo)片(pian)結構(gou)、直動(dong)活(huo)塞結構(gou)、分步直動(dong)活(huo)塞結構(gou)、先導活(huo)塞結構(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)按(an)照功能分類：水用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、氨用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、液體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、微型(xing)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、液壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、油用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)、防(fang)爆電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)等。