電(dian)磁(ci)閥(fa)(fa)(fa)（Electromagnetic valve）是(shi)用(yong)(yong)電(dian)磁(ci)控(kong)(kong)制的(de)工業設備，是(shi)用(yong)(yong)來控(kong)(kong)制流體(ti)的(de)自動化基礎(chu)元件，屬(shu)于(yu)執行器，并不限于(yu)液壓、氣動。用(yong)(yong)在工業控(kong)(kong)制系(xi)統(tong)中(zhong)調整介質的(de)方向(xiang)、流量、速(su)度和其(qi)他的(de)參數。電(dian)磁(ci)閥(fa)(fa)(fa)可以配合不同(tong)(tong)的(de)電(dian)路來實現預期的(de)控(kong)(kong)制，而控(kong)(kong)制的(de)精度和靈活性都能(neng)夠保(bao)證。電(dian)磁(ci)閥(fa)(fa)(fa)有很多(duo)種，不同(tong)(tong)的(de)電(dian)磁(ci)閥(fa)(fa)(fa)在控(kong)(kong)制系(xi)統(tong)的(de)不同(tong)(tong)位(wei)置(zhi)發(fa)揮(hui)作(zuo)用(yong)(yong)，最常(chang)用(yong)(yong)的(de)是(shi)單(dan)向(xiang)閥(fa)(fa)(fa)、安全閥(fa)(fa)(fa)、方向(xiang)控(kong)(kong)制閥(fa)(fa)(fa)、速(su)度調節閥(fa)(fa)(fa)等。

電(dian)磁(ci)閥里有密閉(bi)的(de)(de)(de)腔(qiang)，在不同位置開有通(tong)(tong)孔(kong)，每個孔(kong)連接不同的(de)(de)(de)油管，腔(qiang)中間是(shi)活(huo)塞，兩面(mian)是(shi)兩塊電(dian)磁(ci)鐵，哪面(mian)的(de)(de)(de)磁(ci)鐵線(xian)圈(quan)通(tong)(tong)電(dian)閥體就會被吸引到哪邊，通(tong)(tong)過(guo)(guo)控(kong)制閥體的(de)(de)(de)移(yi)動來開啟或關閉(bi)不同的(de)(de)(de)排(pai)油孔(kong)，而進油孔(kong)是(shi)常開的(de)(de)(de)，液壓(ya)油就會進入(ru)不同的(de)(de)(de)排(pai)油管，然后通(tong)(tong)過(guo)(guo)油的(de)(de)(de)壓(ya)力來推(tui)動油缸的(de)(de)(de)活(huo)塞，活(huo)塞又(you)帶動活(huo)塞桿(gan)，活(huo)塞桿(gan)帶動機械(xie)裝置。這樣(yang)通(tong)(tong)過(guo)(guo)控(kong)制電(dian)磁(ci)鐵的(de)(de)(de)電(dian)流通(tong)(tong)斷就控(kong)制了機械(xie)運動。

1、電磁閥(fa)從原(yuan)理上分為三大類：

直動式電磁閥

原理：通電(dian)時(shi)，電(dian)磁(ci)線圈產生電(dian)磁(ci)力把關閉(bi)件(jian)從閥(fa)(fa)座上(shang)提起，閥(fa)(fa)門打開(kai)；斷電(dian)時(shi)，電(dian)磁(ci)力消失，彈(dan)簧把關閉(bi)件(jian)壓在閥(fa)(fa)座上(shang)，閥(fa)(fa)門關閉(bi)。

特點：在真空、負壓、零(ling)壓時能正常工(gong)作，但通徑一般不(bu)超過(guo)25mm。

分步直(zhi)動式電磁(ci)閥(fa)

原理：它是一(yi)種直(zhi)動(dong)和(he)先(xian)導(dao)式相(xiang)結合的原理，當入口(kou)與(yu)出(chu)(chu)口(kou)沒有壓(ya)(ya)差時(shi)，通電(dian)后(hou)，電(dian)磁(ci)力(li)(li)直(zhi)接把先(xian)導(dao)小閥(fa)(fa)(fa)和(he)主閥(fa)(fa)(fa)關閉(bi)件依次(ci)向上(shang)提起(qi)，閥(fa)(fa)(fa)門(men)(men)打開。當入口(kou)與(yu)出(chu)(chu)口(kou)達到啟動(dong)壓(ya)(ya)差時(shi)，通電(dian)后(hou)，電(dian)磁(ci)力(li)(li)先(xian)導(dao)小閥(fa)(fa)(fa)，主閥(fa)(fa)(fa)下腔壓(ya)(ya)力(li)(li)上(shang)升，上(shang)腔壓(ya)(ya)力(li)(li)下降，從而(er)利(li)用壓(ya)(ya)差把主閥(fa)(fa)(fa)向上(shang)推開；斷電(dian)時(shi)，先(xian)導(dao)閥(fa)(fa)(fa)利(li)用彈簧(huang)力(li)(li)或(huo)介(jie)質壓(ya)(ya)力(li)(li)推動(dong)關閉(bi)件，向下移動(dong)，使閥(fa)(fa)(fa)門(men)(men)關閉(bi)。

特點：在(zai)零壓(ya)差或(huo)真空、高壓(ya)時亦能(neng)可*動作，但功率較大，要求必(bi)須水平安(an)裝。

先導式電磁閥

原理：通(tong)電(dian)時，電(dian)磁力(li)把(ba)先導(dao)孔打(da)開，上(shang)腔室壓力(li)迅速下降，在關 閉(bi)(bi)件(jian)周圍形成上(shang)低下高(gao)(gao)的壓差，流體壓力(li)推動(dong)關閉(bi)(bi)件(jian)向上(shang)移(yi)動(dong)，閥門(men)打(da)開；斷(duan)電(dian)時，彈簧力(li)把(ba)先導(dao)孔關閉(bi)(bi)，入(ru)口壓力(li)通(tong)過旁通(tong)孔迅速腔室在關閥件(jian)周圍形成下低上(shang)高(gao)(gao)的壓差，流體壓力(li)推動(dong)關閉(bi)(bi)件(jian)向下移(yi)動(dong)，關閉(bi)(bi)閥門(men)。

特點(dian)：流體壓力范圍上限較高，可(ke)任意安裝（需定制）但必須滿足(zu)流體壓差條(tiao)件(jian)。

2、電磁閥(fa)從閥(fa)結(jie)(jie)構和材料上的不同(tong)與(yu)原理上的區(qu)別(bie)，分(fen)(fen)為六(liu)個(ge)分(fen)(fen)支(zhi)小類：直(zhi)動(dong)(dong)膜片(pian)(pian)結(jie)(jie)構、分(fen)(fen)步直(zhi)動(dong)(dong)膜片(pian)(pian)結(jie)(jie)構、先(xian)(xian)導膜片(pian)(pian)結(jie)(jie)構、直(zhi)動(dong)(dong)活塞(sai)結(jie)(jie)構、分(fen)(fen)步直(zhi)動(dong)(dong)活塞(sai)結(jie)(jie)構、先(xian)(xian)導活塞(sai)結(jie)(jie)構。

3、電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)按照功能分類：水(shui)用(yong)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、蒸(zheng)汽電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、制冷電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、低溫電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、燃氣電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、消防電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、氨用(yong)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、氣體電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、液體電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、微(wei)(wei)型電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、脈沖(chong)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、液壓(ya)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa) 常開電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、油用(yong)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、直流電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、高壓(ya)電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)、防爆電(dian)(dian)(dian)磁(ci)(ci)(ci)(ci)閥(fa)等。