為了防止(zhi)無(wu)塵(chen)室(shi)(shi)受到(dao)污(wu)染，室(shi)(shi)內必須(xu)保持(chi)正壓(ya)(ya)(ya)，如(ru)果無(wu)塵(chen)室(shi)(shi)內壓(ya)(ya)(ya)力過(guo)高，造成門(men)扇(shan)不(bu)易開(kai)關，因(yin)而使(shi)用(yong)液壓(ya)(ya)(ya)閥門(men)來(lai)保持(chi)無(wu)塵(chen)室(shi)(shi)內之(zhi)微(wei)正壓(ya)(ya)(ya)，通(tong)過(guo)泄壓(ya)(ya)(ya)風(feng)(feng)門(men)的(de)風(feng)(feng)量一般在(zai)100-120m3/h之(zhi)間(jian)(jian)，保持(chi)壓(ya)(ya)(ya)差在(zai)5-40Pa之(zhi)間(jian)(jian)。