電(dian)(dian)磁閥（Electromagnetic valve）是(shi)用電(dian)(dian)磁控(kong)(kong)(kong)制(zhi)(zhi)的工(gong)業(ye)設備，是(shi)用來控(kong)(kong)(kong)制(zhi)(zhi)流體的自動(dong)化基礎(chu)元件(jian)，屬于執(zhi)行器，并不限于液壓、氣動(dong)。用在工(gong)業(ye)控(kong)(kong)(kong)制(zhi)(zhi)系統中(zhong)調整介質的方(fang)向、流量、速度和其他的參(can)數。電(dian)(dian)磁閥可以配合不同(tong)的電(dian)(dian)路來實(shi)現預期的控(kong)(kong)(kong)制(zhi)(zhi)，而控(kong)(kong)(kong)制(zhi)(zhi)的精度和靈活性都能(neng)夠保證。電(dian)(dian)磁閥有很(hen)多種(zhong)，不同(tong)的電(dian)(dian)磁閥在控(kong)(kong)(kong)制(zhi)(zhi)系統的不同(tong)位置發(fa)揮作(zuo)用，最常用的是(shi)單向閥、安全閥、方(fang)向控(kong)(kong)(kong)制(zhi)(zhi)閥、速度調節(jie)閥等(deng)。

電磁閥(fa)里有密閉(bi)的(de)(de)腔，在不同位置開(kai)有通(tong)(tong)孔(kong)，每個(ge)孔(kong)連接不同的(de)(de)油管，腔中間是(shi)活(huo)(huo)塞，兩面(mian)是(shi)兩塊電磁鐵(tie)，哪面(mian)的(de)(de)磁鐵(tie)線圈通(tong)(tong)電閥(fa)體就(jiu)會(hui)被吸引到哪邊，通(tong)(tong)過控(kong)制閥(fa)體的(de)(de)移動(dong)來(lai)開(kai)啟或關閉(bi)不同的(de)(de)排油孔(kong)，而進(jin)油孔(kong)是(shi)常開(kai)的(de)(de)，液壓油就(jiu)會(hui)進(jin)入不同的(de)(de)排油管，然(ran)后通(tong)(tong)過油的(de)(de)壓力來(lai)推動(dong)油缸的(de)(de)活(huo)(huo)塞，活(huo)(huo)塞又帶(dai)動(dong)活(huo)(huo)塞桿，活(huo)(huo)塞桿帶(dai)動(dong)機(ji)械裝(zhuang)置。這(zhe)樣通(tong)(tong)過控(kong)制電磁鐵(tie)的(de)(de)電流通(tong)(tong)斷(duan)就(jiu)控(kong)制了機(ji)械運動(dong)。

1、電磁閥從(cong)原理(li)上分為三大類：

直動(dong)式電磁閥

原理：通電時(shi)，電磁(ci)(ci)線圈產生電磁(ci)(ci)力把(ba)關(guan)閉件從閥座上提起(qi)，閥門打(da)開；斷電時(shi)，電磁(ci)(ci)力消失，彈(dan)簧把(ba)關(guan)閉件壓在閥座上，閥門關(guan)閉。

特點：在真空、負壓、零(ling)壓時能正(zheng)常工作，但通徑一般(ban)不超過25mm。

分步直動式電磁閥

原理：它是一種直(zhi)動和先(xian)(xian)導式相結合的原理，當入口(kou)與出(chu)口(kou)沒(mei)有壓(ya)(ya)(ya)差時，通(tong)電(dian)后，電(dian)磁(ci)力(li)(li)直(zhi)接(jie)把(ba)先(xian)(xian)導小閥(fa)和主閥(fa)關閉(bi)件(jian)依次(ci)向(xiang)上(shang)提起，閥(fa)門(men)打開。當入口(kou)與出(chu)口(kou)達到啟動壓(ya)(ya)(ya)差時，通(tong)電(dian)后，電(dian)磁(ci)力(li)(li)先(xian)(xian)導小閥(fa)，主閥(fa)下(xia)腔壓(ya)(ya)(ya)力(li)(li)上(shang)升(sheng)，上(shang)腔壓(ya)(ya)(ya)力(li)(li)下(xia)降，從而利(li)用壓(ya)(ya)(ya)差把(ba)主閥(fa)向(xiang)上(shang)推開；斷(duan)電(dian)時，先(xian)(xian)導閥(fa)利(li)用彈簧力(li)(li)或介質壓(ya)(ya)(ya)力(li)(li)推動關閉(bi)件(jian)，向(xiang)下(xia)移(yi)動，使閥(fa)門(men)關閉(bi)。

特點：在零壓差或真空(kong)、高壓時亦能可(ke)*動作，但功(gong)率(lv)較大，要求必須水平安裝。

先(xian)導式電磁閥

原理：通電時，電磁力(li)把先導孔打(da)(da)開，上腔室壓(ya)力(li)迅(xun)速下(xia)降，在(zai)關(guan)(guan) 閉件(jian)周圍形成(cheng)上低(di)下(xia)高(gao)的壓(ya)差，流體壓(ya)力(li)推動(dong)(dong)關(guan)(guan)閉件(jian)向(xiang)上移動(dong)(dong)，閥(fa)門打(da)(da)開；斷電時，彈簧力(li)把先導孔關(guan)(guan)閉，入(ru)口壓(ya)力(li)通過旁通孔迅(xun)速腔室在(zai)關(guan)(guan)閥(fa)件(jian)周圍形成(cheng)下(xia)低(di)上高(gao)的壓(ya)差，流體壓(ya)力(li)推動(dong)(dong)關(guan)(guan)閉件(jian)向(xiang)下(xia)移動(dong)(dong)，關(guan)(guan)閉閥(fa)門。

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

2、電磁閥從閥結(jie)(jie)(jie)(jie)構(gou)和材(cai)料(liao)上的不同(tong)與原理上的區別，分(fen)(fen)為六個分(fen)(fen)支小類：直動膜(mo)片結(jie)(jie)(jie)(jie)構(gou)、分(fen)(fen)步(bu)直動膜(mo)片結(jie)(jie)(jie)(jie)構(gou)、先(xian)導(dao)膜(mo)片結(jie)(jie)(jie)(jie)構(gou)、直動活(huo)塞結(jie)(jie)(jie)(jie)構(gou)、分(fen)(fen)步(bu)直動活(huo)塞結(jie)(jie)(jie)(jie)構(gou)、先(xian)導(dao)活(huo)塞結(jie)(jie)(jie)(jie)構(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)按(an)照功能(neng)分類：水用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、低溫(wen)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、消防電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、氨用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、氣(qi)體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、液體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、微(wei)型電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、脈沖(chong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、液壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、油用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、高(gao)壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、防爆電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)等。