電(dian)磁(ci)閥(fa)（Electromagnetic valve）是用(yong)電(dian)磁(ci)控(kong)(kong)制(zhi)的(de)(de)工業(ye)設備，是用(yong)來控(kong)(kong)制(zhi)流體的(de)(de)自動化基礎元件，屬(shu)于(yu)執行器(qi)，并不限于(yu)液(ye)壓、氣動。用(yong)在工業(ye)控(kong)(kong)制(zhi)系(xi)統(tong)中調整介(jie)質的(de)(de)方(fang)向(xiang)、流量、速度和(he)其他的(de)(de)參數。電(dian)磁(ci)閥(fa)可以配合不同的(de)(de)電(dian)路來實(shi)現預期的(de)(de)控(kong)(kong)制(zhi)，而控(kong)(kong)制(zhi)的(de)(de)精(jing)度和(he)靈活(huo)性都能(neng)夠保證。電(dian)磁(ci)閥(fa)有很多種，不同的(de)(de)電(dian)磁(ci)閥(fa)在控(kong)(kong)制(zhi)系(xi)統(tong)的(de)(de)不同位置發(fa)揮作(zuo)用(yong)，最常用(yong)的(de)(de)是單(dan)向(xiang)閥(fa)、安全閥(fa)、方(fang)向(xiang)控(kong)(kong)制(zhi)閥(fa)、速度調節閥(fa)等。

電(dian)磁閥(fa)(fa)里有密閉的(de)腔，在不(bu)同(tong)位(wei)置開(kai)(kai)有通(tong)孔，每個孔連(lian)接(jie)不(bu)同(tong)的(de)油管，腔中間是(shi)活(huo)塞(sai)，兩(liang)面是(shi)兩(liang)塊電(dian)磁鐵(tie)，哪(na)面的(de)磁鐵(tie)線(xian)圈通(tong)電(dian)閥(fa)(fa)體就會被吸引到(dao)哪(na)邊，通(tong)過控制閥(fa)(fa)體的(de)移動(dong)(dong)(dong)來開(kai)(kai)啟(qi)或關閉不(bu)同(tong)的(de)排油孔，而進油孔是(shi)常開(kai)(kai)的(de)，液壓油就會進入(ru)不(bu)同(tong)的(de)排油管，然后(hou)通(tong)過油的(de)壓力來推(tui)動(dong)(dong)(dong)油缸的(de)活(huo)塞(sai)，活(huo)塞(sai)又帶(dai)動(dong)(dong)(dong)活(huo)塞(sai)桿(gan)，活(huo)塞(sai)桿(gan)帶(dai)動(dong)(dong)(dong)機械裝置。這樣通(tong)過控制電(dian)磁鐵(tie)的(de)電(dian)流通(tong)斷就控制了(le)機械運動(dong)(dong)(dong)。

1、電(dian)磁閥從原理上分為三大(da)類：

直動式電磁閥

原理：通電(dian)時(shi)，電(dian)磁(ci)線圈產生(sheng)電(dian)磁(ci)力(li)把關(guan)閉件(jian)從閥座上提起(qi)，閥門打開(kai)；斷電(dian)時(shi)，電(dian)磁(ci)力(li)消失，彈簧把關(guan)閉件(jian)壓在閥座上，閥門關(guan)閉。

特點：在真空、負壓(ya)、零壓(ya)時能(neng)正常工作，但(dan)通徑一般(ban)不超過25mm。

分步直動式(shi)電磁(ci)閥

原(yuan)理：它是(shi)一種直動和(he)先(xian)導(dao)式相(xiang)結合(he)的原(yuan)理，當入(ru)口(kou)(kou)與(yu)出口(kou)(kou)沒有壓(ya)差(cha)時，通(tong)電(dian)后，電(dian)磁力(li)直接把先(xian)導(dao)小閥和(he)主閥關閉(bi)件依次向上(shang)(shang)(shang)提起，閥門打開。當入(ru)口(kou)(kou)與(yu)出口(kou)(kou)達到啟動壓(ya)差(cha)時，通(tong)電(dian)后，電(dian)磁力(li)先(xian)導(dao)小閥，主閥下(xia)腔壓(ya)力(li)上(shang)(shang)(shang)升(sheng)，上(shang)(shang)(shang)腔壓(ya)力(li)下(xia)降，從而利(li)用(yong)壓(ya)差(cha)把主閥向上(shang)(shang)(shang)推開；斷電(dian)時，先(xian)導(dao)閥利(li)用(yong)彈(dan)簧力(li)或介(jie)質壓(ya)力(li)推動關閉(bi)件，向下(xia)移動，使閥門關閉(bi)。

特點：在零壓(ya)差(cha)或真(zhen)空、高壓(ya)時(shi)亦能可*動作，但(dan)功率較大，要求必(bi)須(xu)水(shui)平(ping)安裝。

先導式電磁閥(fa)

原理：通(tong)(tong)電時，電磁(ci)力(li)(li)把先導孔(kong)打(da)開(kai)，上腔室壓(ya)(ya)力(li)(li)迅速下(xia)(xia)降，在關(guan)(guan) 閉(bi)(bi)(bi)件周圍形(xing)成上低(di)(di)下(xia)(xia)高的(de)壓(ya)(ya)差，流體(ti)壓(ya)(ya)力(li)(li)推動(dong)關(guan)(guan)閉(bi)(bi)(bi)件向(xiang)上移動(dong)，閥門打(da)開(kai)；斷(duan)電時，彈簧力(li)(li)把先導孔(kong)關(guan)(guan)閉(bi)(bi)(bi)，入口壓(ya)(ya)力(li)(li)通(tong)(tong)過旁(pang)通(tong)(tong)孔(kong)迅速腔室在關(guan)(guan)閥件周圍形(xing)成下(xia)(xia)低(di)(di)上高的(de)壓(ya)(ya)差，流體(ti)壓(ya)(ya)力(li)(li)推動(dong)關(guan)(guan)閉(bi)(bi)(bi)件向(xiang)下(xia)(xia)移動(dong)，關(guan)(guan)閉(bi)(bi)(bi)閥門。

特點：流體壓力范圍上限較(jiao)高，可任意安裝（需定(ding)制）但必須滿(man)足(zu)流體壓差條(tiao)件。

2、電磁閥從閥結(jie)(jie)(jie)構(gou)(gou)和材料上的(de)不同與原理上的(de)區別，分(fen)為(wei)六個分(fen)支(zhi)小類(lei)：直動膜片結(jie)(jie)(jie)構(gou)(gou)、分(fen)步(bu)直動膜片結(jie)(jie)(jie)構(gou)(gou)、先導(dao)膜片結(jie)(jie)(jie)構(gou)(gou)、直動活(huo)塞結(jie)(jie)(jie)構(gou)(gou)、分(fen)步(bu)直動活(huo)塞結(jie)(jie)(jie)構(gou)(gou)、先導(dao)活(huo)塞結(jie)(jie)(jie)構(gou)(gou)。

3、電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)按照功能分(fen)類：水用電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、燃氣(qi)(qi)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、消(xiao)防電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、氨用電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、氣(qi)(qi)體電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、液體電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、液壓電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa) 常(chang)開電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、油用電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、高壓電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、防爆(bao)電(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)等。