電(dian)磁(ci)閥(fa)(fa)（Electromagnetic valve）是用電(dian)磁(ci)控(kong)制的(de)(de)(de)(de)(de)工業設備，是用來(lai)控(kong)制流(liu)體的(de)(de)(de)(de)(de)自(zi)動化(hua)基(ji)礎元件(jian)，屬于(yu)執行器，并不限于(yu)液壓、氣動。用在工業控(kong)制系統中調整介質的(de)(de)(de)(de)(de)方向、流(liu)量(liang)、速度和其他的(de)(de)(de)(de)(de)參數。電(dian)磁(ci)閥(fa)(fa)可(ke)以配合不同的(de)(de)(de)(de)(de)電(dian)路來(lai)實(shi)現預(yu)期的(de)(de)(de)(de)(de)控(kong)制，而(er)控(kong)制的(de)(de)(de)(de)(de)精度和靈活性(xing)都能夠保(bao)證。電(dian)磁(ci)閥(fa)(fa)有很多種，不同的(de)(de)(de)(de)(de)電(dian)磁(ci)閥(fa)(fa)在控(kong)制系統的(de)(de)(de)(de)(de)不同位置發揮(hui)作用，最常用的(de)(de)(de)(de)(de)是單向閥(fa)(fa)、安全閥(fa)(fa)、方向控(kong)制閥(fa)(fa)、速度調節閥(fa)(fa)等。

電(dian)(dian)磁閥(fa)里有密閉的腔，在不(bu)(bu)(bu)(bu)同位(wei)置開有通(tong)(tong)孔(kong)(kong)，每個孔(kong)(kong)連接不(bu)(bu)(bu)(bu)同的油(you)(you)管，腔中(zhong)間(jian)是(shi)活塞，兩(liang)面是(shi)兩(liang)塊電(dian)(dian)磁鐵，哪(na)面的磁鐵線圈通(tong)(tong)電(dian)(dian)閥(fa)體(ti)就會(hui)被吸引到哪(na)邊，通(tong)(tong)過控(kong)制閥(fa)體(ti)的移動來開啟或(huo)關閉不(bu)(bu)(bu)(bu)同的排(pai)油(you)(you)孔(kong)(kong)，而(er)進(jin)油(you)(you)孔(kong)(kong)是(shi)常開的，液壓油(you)(you)就會(hui)進(jin)入不(bu)(bu)(bu)(bu)同的排(pai)油(you)(you)管，然后(hou)通(tong)(tong)過油(you)(you)的壓力來推(tui)動油(you)(you)缸的活塞，活塞又帶動活塞桿，活塞桿帶動機械裝(zhuang)置。這樣通(tong)(tong)過控(kong)制電(dian)(dian)磁鐵的電(dian)(dian)流通(tong)(tong)斷就控(kong)制了機械運(yun)動。

1、電(dian)磁(ci)閥從原理上(shang)分為三大類：

直動式電磁閥

原理：通電(dian)(dian)時(shi)，電(dian)(dian)磁(ci)線圈產生電(dian)(dian)磁(ci)力(li)(li)把關(guan)閉件(jian)(jian)從閥(fa)座上(shang)提起，閥(fa)門打開(kai)；斷電(dian)(dian)時(shi)，電(dian)(dian)磁(ci)力(li)(li)消(xiao)失，彈簧把關(guan)閉件(jian)(jian)壓在閥(fa)座上(shang)，閥(fa)門關(guan)閉。

特點：在真(zhen)空、負壓(ya)、零壓(ya)時(shi)能(neng)正常工作，但(dan)通徑一(yi)般不超過25mm。

分步直動式(shi)電磁閥

原(yuan)理：它是一種直動(dong)和(he)先(xian)導式相結合的原(yuan)理，當入(ru)口(kou)與出口(kou)沒有壓(ya)差(cha)(cha)時(shi)(shi)，通(tong)電(dian)(dian)后(hou)，電(dian)(dian)磁力直接把(ba)先(xian)導小閥和(he)主(zhu)閥關閉件依次(ci)向(xiang)上提起(qi)，閥門打(da)開。當入(ru)口(kou)與出口(kou)達(da)到啟動(dong)壓(ya)差(cha)(cha)時(shi)(shi)，通(tong)電(dian)(dian)后(hou)，電(dian)(dian)磁力先(xian)導小閥，主(zhu)閥下(xia)(xia)(xia)腔(qiang)壓(ya)力上升，上腔(qiang)壓(ya)力下(xia)(xia)(xia)降，從(cong)而利用壓(ya)差(cha)(cha)把(ba)主(zhu)閥向(xiang)上推(tui)開；斷電(dian)(dian)時(shi)(shi)，先(xian)導閥利用彈簧(huang)力或介質壓(ya)力推(tui)動(dong)關閉件，向(xiang)下(xia)(xia)(xia)移動(dong)，使閥門關閉。

特點(dian)：在零壓(ya)差或(huo)真(zhen)空、高(gao)壓(ya)時亦能可*動作(zuo)，但功率較(jiao)大，要(yao)求(qiu)必須(xu)水平安裝。

先(xian)導(dao)式電(dian)磁閥

原理：通電時(shi)，電磁力(li)(li)(li)把先導孔打開，上(shang)腔室壓(ya)力(li)(li)(li)迅速(su)下降，在(zai)關(guan) 閉(bi)件周(zhou)圍形(xing)成上(shang)低下高的壓(ya)差，流體壓(ya)力(li)(li)(li)推動(dong)關(guan)閉(bi)件向上(shang)移(yi)動(dong)，閥(fa)門(men)打開；斷電時(shi)，彈(dan)簧力(li)(li)(li)把先導孔關(guan)閉(bi)，入口壓(ya)力(li)(li)(li)通過(guo)旁通孔迅速(su)腔室在(zai)關(guan)閥(fa)件周(zhou)圍形(xing)成下低上(shang)高的壓(ya)差，流體壓(ya)力(li)(li)(li)推動(dong)關(guan)閉(bi)件向下移(yi)動(dong)，關(guan)閉(bi)閥(fa)門(men)。

特點：流體壓力范圍(wei)上(shang)限較高(gao)，可任意安裝（需(xu)定制(zhi)）但必須滿(man)足流體壓差條件(jian)。

2、電磁閥(fa)從閥(fa)結(jie)(jie)(jie)構(gou)(gou)(gou)和(he)材料上(shang)的(de)不同與原理上(shang)的(de)區別，分為六個分支小類：直(zhi)動膜(mo)片結(jie)(jie)(jie)構(gou)(gou)(gou)、分步直(zhi)動膜(mo)片結(jie)(jie)(jie)構(gou)(gou)(gou)、先導膜(mo)片結(jie)(jie)(jie)構(gou)(gou)(gou)、直(zhi)動活塞(sai)(sai)結(jie)(jie)(jie)構(gou)(gou)(gou)、分步直(zhi)動活塞(sai)(sai)結(jie)(jie)(jie)構(gou)(gou)(gou)、先導活塞(sai)(sai)結(jie)(jie)(jie)構(gou)(gou)(gou)。

3、電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)按照功能分類：水用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、蒸汽電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、制冷電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、低溫(wen)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、燃氣(qi)(qi)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、消防(fang)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、氨用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、氣(qi)(qi)體(ti)(ti)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、液(ye)體(ti)(ti)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、微型電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、脈沖電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、液(ye)壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa) 常開電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、油用(yong)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、直流電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、高壓(ya)電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)、防(fang)爆電(dian)(dian)(dian)(dian)磁(ci)(ci)(ci)閥(fa)(fa)等。