電(dian)磁閥(fa)（Electromagnetic valve）是用(yong)電(dian)磁控(kong)(kong)(kong)(kong)制(zhi)的(de)(de)工業設備(bei)，是用(yong)來(lai)控(kong)(kong)(kong)(kong)制(zhi)流(liu)體的(de)(de)自動化基(ji)礎(chu)元(yuan)件，屬于(yu)執行器，并(bing)不限于(yu)液壓、氣動。用(yong)在工業控(kong)(kong)(kong)(kong)制(zhi)系統中(zhong)調(diao)(diao)整介質(zhi)的(de)(de)方(fang)向、流(liu)量、速度和其他的(de)(de)參(can)數。電(dian)磁閥(fa)可以(yi)配合不同的(de)(de)電(dian)路來(lai)實現預期的(de)(de)控(kong)(kong)(kong)(kong)制(zhi)，而控(kong)(kong)(kong)(kong)制(zhi)的(de)(de)精度和靈活(huo)性都能(neng)夠保(bao)證(zheng)。電(dian)磁閥(fa)有很多種，不同的(de)(de)電(dian)磁閥(fa)在控(kong)(kong)(kong)(kong)制(zhi)系統的(de)(de)不同位置發揮作(zuo)用(yong)，最常用(yong)的(de)(de)是單向閥(fa)、安全(quan)閥(fa)、方(fang)向控(kong)(kong)(kong)(kong)制(zhi)閥(fa)、速度調(diao)(diao)節(jie)閥(fa)等(deng)。

電(dian)(dian)磁(ci)(ci)閥里有(you)密(mi)閉(bi)的(de)(de)(de)腔，在不(bu)(bu)同(tong)位置開(kai)有(you)通(tong)孔(kong)，每個(ge)孔(kong)連接(jie)不(bu)(bu)同(tong)的(de)(de)(de)油(you)管，腔中間(jian)是活(huo)塞(sai)，兩面是兩塊電(dian)(dian)磁(ci)(ci)鐵，哪面的(de)(de)(de)磁(ci)(ci)鐵線圈通(tong)電(dian)(dian)閥體(ti)就(jiu)會(hui)被吸引到(dao)哪邊(bian)，通(tong)過控制(zhi)閥體(ti)的(de)(de)(de)移動(dong)(dong)來開(kai)啟或(huo)關閉(bi)不(bu)(bu)同(tong)的(de)(de)(de)排油(you)孔(kong)，而進(jin)油(you)孔(kong)是常開(kai)的(de)(de)(de)，液壓(ya)油(you)就(jiu)會(hui)進(jin)入(ru)不(bu)(bu)同(tong)的(de)(de)(de)排油(you)管，然后通(tong)過油(you)的(de)(de)(de)壓(ya)力來推動(dong)(dong)油(you)缸(gang)的(de)(de)(de)活(huo)塞(sai)，活(huo)塞(sai)又帶動(dong)(dong)活(huo)塞(sai)桿，活(huo)塞(sai)桿帶動(dong)(dong)機(ji)械(xie)裝置。這(zhe)樣通(tong)過控制(zhi)電(dian)(dian)磁(ci)(ci)鐵的(de)(de)(de)電(dian)(dian)流(liu)通(tong)斷就(jiu)控制(zhi)了(le)機(ji)械(xie)運動(dong)(dong)。

1、電磁閥從原理上(shang)分為(wei)三大類：

直動式電磁(ci)閥

原理：通電時，電磁線圈產生電磁力(li)把(ba)關(guan)閉件(jian)從閥座(zuo)上提起(qi)，閥門打開；斷電時，電磁力(li)消失，彈簧把(ba)關(guan)閉件(jian)壓在閥座(zuo)上，閥門關(guan)閉。

特點：在(zai)真(zhen)空、負壓(ya)、零壓(ya)時能正常工作，但通徑一(yi)般不(bu)超過(guo)25mm。

分步直動式電磁(ci)閥

原理：它是一種直動(dong)(dong)和(he)先(xian)(xian)導式相結合的原理，當(dang)入(ru)口(kou)與(yu)出口(kou)沒有壓差時(shi)，通電(dian)(dian)(dian)后(hou)，電(dian)(dian)(dian)磁(ci)力(li)直接把先(xian)(xian)導小(xiao)閥(fa)和(he)主(zhu)閥(fa)關閉件(jian)依次向(xiang)(xiang)上(shang)提起(qi)，閥(fa)門打開。當(dang)入(ru)口(kou)與(yu)出口(kou)達到啟(qi)動(dong)(dong)壓差時(shi)，通電(dian)(dian)(dian)后(hou)，電(dian)(dian)(dian)磁(ci)力(li)先(xian)(xian)導小(xiao)閥(fa)，主(zhu)閥(fa)下腔(qiang)壓力(li)上(shang)升，上(shang)腔(qiang)壓力(li)下降，從而利(li)用壓差把主(zhu)閥(fa)向(xiang)(xiang)上(shang)推(tui)開；斷電(dian)(dian)(dian)時(shi)，先(xian)(xian)導閥(fa)利(li)用彈簧力(li)或介質壓力(li)推(tui)動(dong)(dong)關閉件(jian)，向(xiang)(xiang)下移動(dong)(dong)，使閥(fa)門關閉。

特點：在零壓差或(huo)真空(kong)、高壓時亦能可*動(dong)作，但功率較大，要求(qiu)必(bi)須水平安裝。

先(xian)導式電磁閥

原理：通電時(shi)，電磁力把(ba)先導(dao)孔(kong)打(da)開，上(shang)腔(qiang)(qiang)室壓(ya)(ya)力迅速(su)下(xia)降，在(zai)關(guan)(guan) 閉件(jian)周圍形成(cheng)上(shang)低(di)下(xia)高的壓(ya)(ya)差(cha)，流體(ti)壓(ya)(ya)力推動(dong)關(guan)(guan)閉件(jian)向上(shang)移(yi)(yi)動(dong)，閥(fa)門打(da)開；斷電時(shi)，彈簧力把(ba)先導(dao)孔(kong)關(guan)(guan)閉，入口壓(ya)(ya)力通過旁通孔(kong)迅速(su)腔(qiang)(qiang)室在(zai)關(guan)(guan)閥(fa)件(jian)周圍形成(cheng)下(xia)低(di)上(shang)高的壓(ya)(ya)差(cha)，流體(ti)壓(ya)(ya)力推動(dong)關(guan)(guan)閉件(jian)向下(xia)移(yi)(yi)動(dong)，關(guan)(guan)閉閥(fa)門。

特點(dian)：流體(ti)壓(ya)力(li)范圍上限較高，可(ke)任意安裝（需(xu)定制）但必須滿(man)足流體(ti)壓(ya)差條件。

2、電磁閥從閥結(jie)(jie)(jie)構和材料上的不同與原理上的區別，分為六個分支小類：直(zhi)(zhi)動(dong)膜片結(jie)(jie)(jie)構、分步(bu)(bu)直(zhi)(zhi)動(dong)膜片結(jie)(jie)(jie)構、先導膜片結(jie)(jie)(jie)構、直(zhi)(zhi)動(dong)活塞(sai)結(jie)(jie)(jie)構、分步(bu)(bu)直(zhi)(zhi)動(dong)活塞(sai)結(jie)(jie)(jie)構、先導活塞(sai)結(jie)(jie)(jie)構。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)按照功能分類：水用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、制冷(leng)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、燃氣電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、消防電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、氨用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、液體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、液壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、油用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、直流電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、高(gao)壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)、防爆電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)(fa)等(deng)。