電磁閥(fa)(fa)（Electromagnetic valve）是用電磁控(kong)制的(de)工(gong)業(ye)設備，是用來(lai)控(kong)制流(liu)體的(de)自動化基礎元件，屬于執行器，并(bing)不限(xian)于液(ye)壓、氣動。用在(zai)工(gong)業(ye)控(kong)制系統(tong)中調(diao)整(zheng)介質(zhi)的(de)方向、流(liu)量、速度(du)和其他(ta)的(de)參數(shu)。電磁閥(fa)(fa)可(ke)以配合不同(tong)的(de)電路來(lai)實現預期的(de)控(kong)制，而控(kong)制的(de)精(jing)度(du)和靈活性都(dou)能夠保(bao)證。電磁閥(fa)(fa)有很多種，不同(tong)的(de)電磁閥(fa)(fa)在(zai)控(kong)制系統(tong)的(de)不同(tong)位置發揮作用，最常用的(de)是單向閥(fa)(fa)、安(an)全閥(fa)(fa)、方向控(kong)制閥(fa)(fa)、速度(du)調(diao)節(jie)閥(fa)(fa)等。

電(dian)(dian)磁閥(fa)里有密閉的(de)(de)腔，在不同(tong)位置開有通(tong)孔，每(mei)個孔連接不同(tong)的(de)(de)油管(guan)，腔中間是活塞，兩面(mian)是兩塊電(dian)(dian)磁鐵(tie)(tie)，哪面(mian)的(de)(de)磁鐵(tie)(tie)線圈通(tong)電(dian)(dian)閥(fa)體(ti)就(jiu)會被吸引到哪邊，通(tong)過控(kong)制閥(fa)體(ti)的(de)(de)移動(dong)來開啟或關閉不同(tong)的(de)(de)排油孔，而進油孔是常(chang)開的(de)(de)，液壓(ya)油就(jiu)會進入不同(tong)的(de)(de)排油管(guan)，然(ran)后通(tong)過油的(de)(de)壓(ya)力來推動(dong)油缸的(de)(de)活塞，活塞又帶動(dong)活塞桿，活塞桿帶動(dong)機械(xie)裝置。這樣通(tong)過控(kong)制電(dian)(dian)磁鐵(tie)(tie)的(de)(de)電(dian)(dian)流通(tong)斷就(jiu)控(kong)制了(le)機械(xie)運(yun)動(dong)。

1、電磁(ci)閥從原理上分為(wei)三大(da)類：

直(zhi)動式(shi)電磁閥(fa)

原理：通電時，電磁線圈產生電磁力把(ba)關閉(bi)件從閥座上(shang)提起(qi)，閥門打開；斷電時，電磁力消失，彈簧把(ba)關閉(bi)件壓在閥座上(shang)，閥門關閉(bi)。

特點：在真空、負(fu)壓(ya)、零壓(ya)時能正常工作(zuo)，但通徑一般(ban)不(bu)超過25mm。

分步直動(dong)式電磁閥(fa)

原(yuan)理(li)：它(ta)是(shi)一(yi)種直動和先(xian)導式相結合的原(yuan)理(li)，當入口(kou)與出口(kou)沒(mei)有(you)壓差時，通電(dian)后，電(dian)磁(ci)力(li)(li)直接把先(xian)導小閥和主閥關(guan)閉件(jian)依次向上(shang)提起，閥門打開(kai)。當入口(kou)與出口(kou)達(da)到啟動壓差時，通電(dian)后，電(dian)磁(ci)力(li)(li)先(xian)導小閥，主閥下(xia)腔壓力(li)(li)上(shang)升，上(shang)腔壓力(li)(li)下(xia)降(jiang)，從而利用壓差把主閥向上(shang)推開(kai)；斷電(dian)時，先(xian)導閥利用彈簧(huang)力(li)(li)或(huo)介(jie)質壓力(li)(li)推動關(guan)閉件(jian)，向下(xia)移動，使(shi)閥門關(guan)閉。

特點：在零壓差或真空、高壓時亦能可*動作，但(dan)功(gong)率較大(da)，要求必(bi)須水平安裝。

先導式電磁閥

原理：通電(dian)時(shi)，電(dian)磁力把(ba)(ba)先(xian)導(dao)孔打(da)(da)開，上(shang)(shang)(shang)腔室(shi)壓力迅速下降，在關(guan) 閉(bi)(bi)件(jian)周圍形成上(shang)(shang)(shang)低(di)(di)下高(gao)(gao)的壓差，流體壓力推動(dong)關(guan)閉(bi)(bi)件(jian)向上(shang)(shang)(shang)移動(dong)，閥(fa)門打(da)(da)開；斷(duan)電(dian)時(shi)，彈簧力把(ba)(ba)先(xian)導(dao)孔關(guan)閉(bi)(bi)，入(ru)口(kou)壓力通過(guo)旁(pang)通孔迅速腔室(shi)在關(guan)閥(fa)件(jian)周圍形成下低(di)(di)上(shang)(shang)(shang)高(gao)(gao)的壓差，流體壓力推動(dong)關(guan)閉(bi)(bi)件(jian)向下移動(dong)，關(guan)閉(bi)(bi)閥(fa)門。

特(te)點：流體(ti)壓力范(fan)圍(wei)上限(xian)較(jiao)高，可任意安裝（需定制(zhi)）但必須滿(man)足流體(ti)壓差條件。

2、電磁閥從(cong)閥結(jie)構(gou)和材料(liao)上(shang)(shang)的不(bu)同與原理上(shang)(shang)的區別，分為六個分支小類：直(zhi)動膜片結(jie)構(gou)、分步直(zhi)動膜片結(jie)構(gou)、先導膜片結(jie)構(gou)、直(zhi)動活塞(sai)結(jie)構(gou)、分步直(zhi)動活塞(sai)結(jie)構(gou)、先導活塞(sai)結(jie)構(gou)。

3、電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)按照功能分類：水用(yong)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、蒸(zheng)汽(qi)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、燃(ran)氣電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、氨用(yong)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、液(ye)(ye)體電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、微型(xing)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、脈(mo)沖電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、液(ye)(ye)壓(ya)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa) 常(chang)開(kai)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、油用(yong)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、高(gao)壓(ya)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)、防(fang)爆(bao)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)(fa)等。