為了防止(zhi)無(wu)塵(chen)室(shi)(shi)受到污染，室(shi)(shi)內必須保持(chi)正(zheng)壓(ya)(ya)，如(ru)果(guo)無(wu)塵(chen)室(shi)(shi)內壓(ya)(ya)力(li)過高，造(zao)成(cheng)門(men)扇(shan)不易開關，因而(er)使(shi)用(yong)液壓(ya)(ya)閥門(men)來保持(chi)無(wu)塵(chen)室(shi)(shi)內之(zhi)微正(zheng)壓(ya)(ya)，通過泄壓(ya)(ya)風門(men)的風量一(yi)般在100-120m3/h之(zhi)間，保持(chi)壓(ya)(ya)差在5-40Pa之(zhi)間。