電磁(ci)閥(fa)(fa)（Electromagnetic valve）是(shi)用(yong)(yong)電磁(ci)控(kong)制(zhi)(zhi)的(de)(de)工業設(she)備，是(shi)用(yong)(yong)來(lai)控(kong)制(zhi)(zhi)流體的(de)(de)自動化基礎元件，屬于執行器，并不(bu)限于液壓、氣動。用(yong)(yong)在工業控(kong)制(zhi)(zhi)系(xi)統(tong)中(zhong)調整介質的(de)(de)方向(xiang)(xiang)、流量、速度(du)和其他的(de)(de)參數。電磁(ci)閥(fa)(fa)可以配合不(bu)同的(de)(de)電路來(lai)實(shi)現預(yu)期的(de)(de)控(kong)制(zhi)(zhi)，而控(kong)制(zhi)(zhi)的(de)(de)精(jing)度(du)和靈活性(xing)都能夠保(bao)證。電磁(ci)閥(fa)(fa)有很多種，不(bu)同的(de)(de)電磁(ci)閥(fa)(fa)在控(kong)制(zhi)(zhi)系(xi)統(tong)的(de)(de)不(bu)同位置發揮(hui)作用(yong)(yong)，最常用(yong)(yong)的(de)(de)是(shi)單向(xiang)(xiang)閥(fa)(fa)、安全閥(fa)(fa)、方向(xiang)(xiang)控(kong)制(zhi)(zhi)閥(fa)(fa)、速度(du)調節閥(fa)(fa)等。

電磁閥(fa)里有(you)密閉的(de)腔，在不同位置開有(you)通(tong)孔(kong)(kong)，每個孔(kong)(kong)連(lian)接(jie)不同的(de)油(you)(you)管(guan)，腔中(zhong)間是活塞，兩(liang)面是兩(liang)塊電磁鐵(tie)，哪(na)面的(de)磁鐵(tie)線(xian)圈通(tong)電閥(fa)體就(jiu)會被吸引(yin)到(dao)哪(na)邊，通(tong)過(guo)(guo)控制(zhi)閥(fa)體的(de)移(yi)動(dong)來開啟(qi)或關閉不同的(de)排(pai)油(you)(you)孔(kong)(kong)，而進油(you)(you)孔(kong)(kong)是常開的(de)，液壓(ya)油(you)(you)就(jiu)會進入不同的(de)排(pai)油(you)(you)管(guan)，然后通(tong)過(guo)(guo)油(you)(you)的(de)壓(ya)力(li)來推(tui)動(dong)油(you)(you)缸的(de)活塞，活塞又(you)帶(dai)動(dong)活塞桿(gan)，活塞桿(gan)帶(dai)動(dong)機(ji)械裝置。這樣通(tong)過(guo)(guo)控制(zhi)電磁鐵(tie)的(de)電流通(tong)斷(duan)就(jiu)控制(zhi)了機(ji)械運(yun)動(dong)。

1、電磁(ci)閥從原(yuan)理上分為三大類：

直(zhi)動式電磁閥(fa)

原(yuan)理：通電時(shi)，電磁線圈產生(sheng)電磁力把關閉件從(cong)閥座上(shang)提(ti)起，閥門(men)打(da)開；斷(duan)電時(shi)，電磁力消失，彈簧把關閉件壓(ya)在閥座上(shang)，閥門(men)關閉。

特點：在真空、負壓、零壓時能正常工(gong)作，但通(tong)徑一般(ban)不超過(guo)25mm。

分(fen)步直動式電磁閥

原理：它(ta)是(shi)一種直動(dong)和先(xian)導(dao)式相結合的(de)原理，當(dang)入(ru)口(kou)(kou)與出口(kou)(kou)沒有壓(ya)差(cha)(cha)(cha)時，通(tong)電后，電磁力直接把先(xian)導(dao)小閥和主閥關(guan)閉件(jian)依(yi)次(ci)向(xiang)上(shang)提起，閥門打開。當(dang)入(ru)口(kou)(kou)與出口(kou)(kou)達到(dao)啟動(dong)壓(ya)差(cha)(cha)(cha)時，通(tong)電后，電磁力先(xian)導(dao)小閥，主閥下(xia)腔壓(ya)力上(shang)升，上(shang)腔壓(ya)力下(xia)降，從(cong)而利用(yong)(yong)壓(ya)差(cha)(cha)(cha)把主閥向(xiang)上(shang)推(tui)開；斷(duan)電時，先(xian)導(dao)閥利用(yong)(yong)彈簧力或介質壓(ya)力推(tui)動(dong)關(guan)閉件(jian)，向(xiang)下(xia)移動(dong)，使閥門關(guan)閉。

特點：在零壓差或真空(kong)、高壓時亦能可*動作，但功率較大，要求必(bi)須水平安裝。

先導式電磁閥

原(yuan)理(li)：通電時(shi)，電磁力(li)(li)把先導孔(kong)打開，上(shang)腔(qiang)室(shi)(shi)壓力(li)(li)迅(xun)速(su)(su)下降，在關(guan) 閉(bi)(bi)件(jian)(jian)周圍形(xing)成(cheng)上(shang)低下高(gao)的(de)壓差(cha)，流體壓力(li)(li)推(tui)動(dong)關(guan)閉(bi)(bi)件(jian)(jian)向上(shang)移動(dong)，閥(fa)門(men)打開；斷(duan)電時(shi)，彈簧力(li)(li)把先導孔(kong)關(guan)閉(bi)(bi)，入口壓力(li)(li)通過旁通孔(kong)迅(xun)速(su)(su)腔(qiang)室(shi)(shi)在關(guan)閥(fa)件(jian)(jian)周圍形(xing)成(cheng)下低上(shang)高(gao)的(de)壓差(cha)，流體壓力(li)(li)推(tui)動(dong)關(guan)閉(bi)(bi)件(jian)(jian)向下移動(dong)，關(guan)閉(bi)(bi)閥(fa)門(men)。

特點：流體(ti)壓力范圍(wei)上限較(jiao)高，可任意安(an)裝（需定制）但(dan)必須(xu)滿(man)足流體(ti)壓差條(tiao)件。

2、電磁(ci)閥(fa)從閥(fa)結(jie)構和材料上(shang)的不(bu)同(tong)與(yu)原理上(shang)的區別，分(fen)為六個分(fen)支小類：直動(dong)(dong)膜片(pian)(pian)結(jie)構、分(fen)步直動(dong)(dong)膜片(pian)(pian)結(jie)構、先(xian)導膜片(pian)(pian)結(jie)構、直動(dong)(dong)活塞(sai)結(jie)構、分(fen)步直動(dong)(dong)活塞(sai)結(jie)構、先(xian)導活塞(sai)結(jie)構。

3、電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)按照功能(neng)分類(lei)：水用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、燃氣(qi)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、氨(an)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、氣(qi)體電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、液體電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、微型電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、液壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、油用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、高壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)、防(fang)爆電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)閥(fa)(fa)(fa)等。