減壓閥的(de)工作原理 

    減(jian)壓(ya)閥(fa)是氣動調(diao)節閥(fa)的一個(ge)必備配(pei)件，主(zhu)要作用(yong)是將氣源的壓(ya)力減(jian)壓(ya)并(bing)穩(wen)定(ding)到一個(ge)定(ding)值，以便于(yu)調(diao)節閥(fa)能(neng)夠獲得穩(wen)定(ding)的氣源動力用(yong)于(yu)調(diao)節控制。 按結構形式(shi)可分為(wei)薄膜式(shi)、彈簧(huang)薄膜式(shi)、活塞式(shi)、杠(gang)桿(gan)式(shi)和波(bo)紋(wen)管式(shi)；按閥(fa)座數(shu)目(mu)可人為(wei)單座式(shi)和雙座式(shi)；按閥(fa)瓣的位置不同(tong)可分為(wei)正作用(yong)式(shi)和反作用(yong)式(shi)。 

    當減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)的(de)輸(shu)出壓(ya)力較(jiao)(jiao)高(gao)或通徑較(jiao)(jiao)大(da)時(shi)，用調(diao)壓(ya)彈簧直(zhi)接調(diao)壓(ya)，則(ze)彈簧剛(gang)度(du)必然過大(da)，流(liu)量變(bian)化時(shi)，輸(shu)出壓(ya)力波動(dong)(dong)較(jiao)(jiao)大(da)，閥(fa)(fa)的(de)結(jie)構尺寸也將增大(da)。為(wei)(wei)了(le)(le)克服這些缺(que)點，可采用先導(dao)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)。先導(dao)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)的(de)工(gong)作(zuo)原理(li)與直(zhi)動(dong)(dong)式的(de)基本(ben)相(xiang)同。先導(dao)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)所用的(de)調(diao)壓(ya)氣(qi)(qi)體(ti)(ti)，是由(you)小(xiao)型(xing)的(de)直(zhi)動(dong)(dong)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)供(gong)給的(de)。若把(ba)小(xiao)型(xing)直(zhi)動(dong)(dong)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)裝(zhuang)在(zai)(zai)閥(fa)(fa)體(ti)(ti)內(nei)部(bu)，則(ze)稱為(wei)(wei)內(nei)部(bu)先導(dao)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)；若將小(xiao)型(xing)直(zhi)動(dong)(dong)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)裝(zhuang)在(zai)(zai)主閥(fa)(fa)體(ti)(ti)外(wai)部(bu)，則(ze)稱為(wei)(wei)外(wai)部(bu)先導(dao)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)。圖(tu)14—2所示(shi)為(wei)(wei)內(nei)部(bu)先導(dao)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)的(de)結(jie)構圖(tu)，與直(zhi)動(dong)(dong)式減(jian)(jian)(jian)(jian)壓(ya)閥(fa)(fa)相(xiang)比，該(gai)閥(fa)(fa)增加了(le)(le)由(you)噴(pen)嘴(zui)(zui)4、擋板3、固定(ding)節(jie)流(liu)孔9及氣(qi)(qi)室(shi)B所組(zu)成的(de)噴(pen)嘴(zui)(zui)擋板放(fang)大(da)環(huan)節(jie)。當噴(pen)嘴(zui)(zui)與擋板之間的(de)距(ju)離發生(sheng)微小(xiao)變(bian)化時(shi)，就會使(shi)B室(shi)中的(de)壓(ya)力發生(sheng)根明顯(xian)的(de)變(bian)化，從而引(yin)起膜片10有較(jiao)(jiao)大(da)的(de)位移，去控制閥(fa)(fa)芯6的(de)上下移動(dong)(dong)，使(shi)進(jin)氣(qi)(qi)閥(fa)(fa)口8開大(da)或關(guan)小(xiao)、提(ti)高(gao)了(le)(le)對閥(fa)(fa)芯控制的(de)靈敏度(du)，即提(ti)高(gao)了(le)(le)穩壓(ya)精度(du)。