電磁閥（Electromagnetic valve）是用(yong)電磁控(kong)制(zhi)(zhi)(zhi)的(de)(de)(de)工(gong)業(ye)設備，是用(yong)來控(kong)制(zhi)(zhi)(zhi)流(liu)體的(de)(de)(de)自動化(hua)基礎元(yuan)件，屬(shu)于執行(xing)器，并不(bu)限于液壓、氣動。用(yong)在(zai)工(gong)業(ye)控(kong)制(zhi)(zhi)(zhi)系統(tong)中調整(zheng)介質的(de)(de)(de)方向、流(liu)量、速度(du)和其(qi)他(ta)的(de)(de)(de)參(can)數。電磁閥可以(yi)配合不(bu)同(tong)的(de)(de)(de)電路(lu)來實(shi)現(xian)預期的(de)(de)(de)控(kong)制(zhi)(zhi)(zhi)，而控(kong)制(zhi)(zhi)(zhi)的(de)(de)(de)精度(du)和靈活性(xing)都能(neng)夠保證(zheng)。電磁閥有很多種(zhong)，不(bu)同(tong)的(de)(de)(de)電磁閥在(zai)控(kong)制(zhi)(zhi)(zhi)系統(tong)的(de)(de)(de)不(bu)同(tong)位(wei)置發揮作用(yong)，最常用(yong)的(de)(de)(de)是單(dan)向閥、安全閥、方向控(kong)制(zhi)(zhi)(zhi)閥、速度(du)調節閥等。

電(dian)磁閥里有密閉的(de)腔，在不(bu)同(tong)(tong)位置開(kai)有通(tong)孔(kong)，每個孔(kong)連接不(bu)同(tong)(tong)的(de)油管，腔中(zhong)間是(shi)活塞(sai)(sai)，兩面(mian)是(shi)兩塊電(dian)磁鐵(tie)，哪(na)面(mian)的(de)磁鐵(tie)線(xian)圈通(tong)電(dian)閥體就會被(bei)吸(xi)引(yin)到哪(na)邊，通(tong)過(guo)控制(zhi)(zhi)閥體的(de)移動(dong)來開(kai)啟或關閉不(bu)同(tong)(tong)的(de)排(pai)油孔(kong)，而進油孔(kong)是(shi)常開(kai)的(de)，液壓油就會進入不(bu)同(tong)(tong)的(de)排(pai)油管，然后通(tong)過(guo)油的(de)壓力來推(tui)動(dong)油缸的(de)活塞(sai)(sai)，活塞(sai)(sai)又帶動(dong)活塞(sai)(sai)桿，活塞(sai)(sai)桿帶動(dong)機(ji)械(xie)裝(zhuang)置。這(zhe)樣通(tong)過(guo)控制(zhi)(zhi)電(dian)磁鐵(tie)的(de)電(dian)流(liu)通(tong)斷就控制(zhi)(zhi)了機(ji)械(xie)運動(dong)。

1、電磁閥從原(yuan)理上分為三大類：

直動(dong)式電(dian)磁(ci)閥(fa)

原(yuan)理：通電(dian)時，電(dian)磁線(xian)圈產生電(dian)磁力把關閉(bi)件(jian)從閥(fa)座上提起，閥(fa)門打開；斷電(dian)時，電(dian)磁力消(xiao)失，彈簧把關閉(bi)件(jian)壓在閥(fa)座上，閥(fa)門關閉(bi)。

特點：在真空、負壓、零壓時能正常工作，但通徑一般不超過25mm。

分步直動式電磁閥

原理(li)：它是一種直動和先(xian)(xian)(xian)導式相(xiang)結合的原理(li)，當(dang)入口(kou)與出(chu)口(kou)沒有壓差(cha)時，通電后(hou)，電磁(ci)(ci)力(li)直接把(ba)先(xian)(xian)(xian)導小閥(fa)(fa)(fa)和主閥(fa)(fa)(fa)關閉件依次(ci)向(xiang)上提(ti)起，閥(fa)(fa)(fa)門打開。當(dang)入口(kou)與出(chu)口(kou)達到啟動壓差(cha)時，通電后(hou)，電磁(ci)(ci)力(li)先(xian)(xian)(xian)導小閥(fa)(fa)(fa)，主閥(fa)(fa)(fa)下(xia)腔壓力(li)上升，上腔壓力(li)下(xia)降，從而利用(yong)壓差(cha)把(ba)主閥(fa)(fa)(fa)向(xiang)上推開；斷電時，先(xian)(xian)(xian)導閥(fa)(fa)(fa)利用(yong)彈(dan)簧(huang)力(li)或介質壓力(li)推動關閉件，向(xiang)下(xia)移動，使閥(fa)(fa)(fa)門關閉。

特點：在(zai)零壓(ya)差或真空(kong)、高(gao)壓(ya)時亦能(neng)可*動作，但功率較大，要求必須水(shui)平安(an)裝。

先導式電(dian)磁(ci)閥

原理：通電(dian)時，電(dian)磁力(li)把(ba)先導孔打(da)(da)開，上(shang)(shang)腔室(shi)(shi)壓力(li)迅(xun)速下降，在關(guan)(guan) 閉(bi)件(jian)(jian)周(zhou)圍形成(cheng)上(shang)(shang)低下高的壓差，流體壓力(li)推動關(guan)(guan)閉(bi)件(jian)(jian)向上(shang)(shang)移動，閥(fa)門打(da)(da)開；斷電(dian)時，彈簧力(li)把(ba)先導孔關(guan)(guan)閉(bi)，入口壓力(li)通過旁通孔迅(xun)速腔室(shi)(shi)在關(guan)(guan)閥(fa)件(jian)(jian)周(zhou)圍形成(cheng)下低上(shang)(shang)高的壓差，流體壓力(li)推動關(guan)(guan)閉(bi)件(jian)(jian)向下移動，關(guan)(guan)閉(bi)閥(fa)門。

特點：流體(ti)壓力范圍上限較高，可任(ren)意(yi)安裝（需定(ding)制(zhi)）但(dan)必須滿(man)足(zu)流體(ti)壓差條件。

2、電磁閥從閥結(jie)構(gou)和材料上的不同與原理上的區別，分(fen)(fen)為六個分(fen)(fen)支小(xiao)類：直(zhi)動膜片(pian)結(jie)構(gou)、分(fen)(fen)步直(zhi)動膜片(pian)結(jie)構(gou)、先導膜片(pian)結(jie)構(gou)、直(zhi)動活塞(sai)結(jie)構(gou)、分(fen)(fen)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)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)按照(zhao)功能分類：水用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、蒸(zheng)汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、制冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、低溫電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、燃(ran)氣電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、消防電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、氨用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、氣體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、液體電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、微(wei)型電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、脈沖(chong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、液壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、油用電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、直(zhi)流電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、高(gao)壓電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)、防爆電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)閥(fa)(fa)(fa)(fa)等。