電磁(ci)閥(fa)(fa)（Electromagnetic valve）是用(yong)(yong)電磁(ci)控(kong)(kong)制(zhi)(zhi)的(de)(de)工業設(she)備，是用(yong)(yong)來控(kong)(kong)制(zhi)(zhi)流體(ti)的(de)(de)自動(dong)化基礎元(yuan)件(jian)，屬于執行器，并不限于液壓、氣動(dong)。用(yong)(yong)在(zai)工業控(kong)(kong)制(zhi)(zhi)系(xi)統中調整介質的(de)(de)方(fang)(fang)向(xiang)、流量、速度(du)(du)和其他的(de)(de)參數。電磁(ci)閥(fa)(fa)可以配合不同(tong)的(de)(de)電路來實現預(yu)期的(de)(de)控(kong)(kong)制(zhi)(zhi)，而控(kong)(kong)制(zhi)(zhi)的(de)(de)精度(du)(du)和靈活性都能(neng)夠(gou)保證。電磁(ci)閥(fa)(fa)有很多種，不同(tong)的(de)(de)電磁(ci)閥(fa)(fa)在(zai)控(kong)(kong)制(zhi)(zhi)系(xi)統的(de)(de)不同(tong)位置(zhi)發揮(hui)作用(yong)(yong)，最常(chang)用(yong)(yong)的(de)(de)是單(dan)向(xiang)閥(fa)(fa)、安全閥(fa)(fa)、方(fang)(fang)向(xiang)控(kong)(kong)制(zhi)(zhi)閥(fa)(fa)、速度(du)(du)調節閥(fa)(fa)等。

電(dian)(dian)磁閥里(li)有(you)密閉的(de)腔(qiang)，在不(bu)同(tong)位(wei)置(zhi)開(kai)有(you)通孔(kong)，每個孔(kong)連(lian)接不(bu)同(tong)的(de)油(you)管，腔(qiang)中間是(shi)活塞(sai)，兩面是(shi)兩塊電(dian)(dian)磁鐵，哪(na)面的(de)磁鐵線圈通電(dian)(dian)閥體就會(hui)被吸引到哪(na)邊，通過(guo)控制(zhi)閥體的(de)移動(dong)(dong)來開(kai)啟(qi)或關閉不(bu)同(tong)的(de)排油(you)孔(kong)，而進(jin)油(you)孔(kong)是(shi)常開(kai)的(de)，液壓油(you)就會(hui)進(jin)入不(bu)同(tong)的(de)排油(you)管，然(ran)后通過(guo)油(you)的(de)壓力來推動(dong)(dong)油(you)缸的(de)活塞(sai)，活塞(sai)又(you)帶動(dong)(dong)活塞(sai)桿，活塞(sai)桿帶動(dong)(dong)機(ji)械裝置(zhi)。這(zhe)樣通過(guo)控制(zhi)電(dian)(dian)磁鐵的(de)電(dian)(dian)流通斷就控制(zhi)了機(ji)械運動(dong)(dong)。

1、電(dian)磁閥從原理(li)上(shang)分為三大(da)類：

直動式電(dian)磁閥

原理：通電(dian)時(shi)，電(dian)磁線(xian)圈產(chan)生電(dian)磁力把關閉件(jian)從閥(fa)座上(shang)提(ti)起(qi)，閥(fa)門打開；斷電(dian)時(shi)，電(dian)磁力消失(shi)，彈簧把關閉件(jian)壓在閥(fa)座上(shang)，閥(fa)門關閉。

特點：在真空(kong)、負壓、零壓時能正常(chang)工(gong)作，但通徑一般(ban)不(bu)超過25mm。

分步直動式(shi)電磁(ci)閥

原理(li)：它是一種直動和先(xian)導(dao)式相(xiang)結合(he)的原理(li)，當入(ru)口(kou)(kou)(kou)與(yu)出口(kou)(kou)(kou)沒有壓(ya)差時，通電(dian)后，電(dian)磁力直接把先(xian)導(dao)小(xiao)閥(fa)(fa)和主(zhu)(zhu)閥(fa)(fa)關(guan)閉件依(yi)次向(xiang)上(shang)提起(qi)，閥(fa)(fa)門打開。當入(ru)口(kou)(kou)(kou)與(yu)出口(kou)(kou)(kou)達到啟(qi)動壓(ya)差時，通電(dian)后，電(dian)磁力先(xian)導(dao)小(xiao)閥(fa)(fa)，主(zhu)(zhu)閥(fa)(fa)下腔(qiang)壓(ya)力上(shang)升，上(shang)腔(qiang)壓(ya)力下降，從(cong)而利用壓(ya)差把主(zhu)(zhu)閥(fa)(fa)向(xiang)上(shang)推開；斷電(dian)時，先(xian)導(dao)閥(fa)(fa)利用彈簧力或(huo)介質壓(ya)力推動關(guan)閉件，向(xiang)下移動，使閥(fa)(fa)門關(guan)閉。

特點：在(zai)零壓差或真空、高壓時亦能(neng)可*動作，但功(gong)率較大(da)，要求(qiu)必須水平安裝。

先導式(shi)電磁閥

原理(li)：通電時(shi)，電磁(ci)力(li)把(ba)先導(dao)孔打(da)開(kai)，上(shang)腔室壓(ya)力(li)迅速下降(jiang)，在關(guan) 閉(bi)件(jian)周圍形成(cheng)(cheng)上(shang)低(di)下高(gao)的壓(ya)差，流體壓(ya)力(li)推動(dong)關(guan)閉(bi)件(jian)向上(shang)移(yi)動(dong)，閥門打(da)開(kai)；斷(duan)電時(shi)，彈簧力(li)把(ba)先導(dao)孔關(guan)閉(bi)，入口(kou)壓(ya)力(li)通過旁通孔迅速腔室在關(guan)閥件(jian)周圍形成(cheng)(cheng)下低(di)上(shang)高(gao)的壓(ya)差，流體壓(ya)力(li)推動(dong)關(guan)閉(bi)件(jian)向下移(yi)動(dong)，關(guan)閉(bi)閥門。

特點：流體壓力范圍上(shang)限較高，可(ke)任意安裝（需定制）但必(bi)須滿足流體壓差條件。

2、電磁閥從(cong)閥結(jie)構(gou)(gou)和材(cai)料上(shang)的不同與原(yuan)理(li)上(shang)的區(qu)別，分為六個分支小類：直(zhi)動(dong)(dong)膜片結(jie)構(gou)(gou)、分步直(zhi)動(dong)(dong)膜片結(jie)構(gou)(gou)、先導膜片結(jie)構(gou)(gou)、直(zhi)動(dong)(dong)活(huo)塞結(jie)構(gou)(gou)、分步直(zhi)動(dong)(dong)活(huo)塞結(jie)構(gou)(gou)、先導活(huo)塞結(jie)構(gou)(gou)。

3、電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)按照功(gong)能分類(lei)：水(shui)用電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、蒸汽(qi)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、制冷電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、低溫電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、消防電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、氨用電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、氣(qi)體電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、液體電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、微(wei)(wei)型電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、脈(mo)沖電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、液壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa) 常開(kai)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、油用電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、直流電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、高(gao)壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、防爆電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)等。