為(wei)了防止無(wu)塵(chen)(chen)室(shi)受到污染，室(shi)內(nei)(nei)(nei)必(bi)須保持正(zheng)壓(ya)(ya)(ya)(ya)，如果(guo)無(wu)塵(chen)(chen)室(shi)內(nei)(nei)(nei)壓(ya)(ya)(ya)(ya)力(li)過高，造(zao)成門(men)扇(shan)不(bu)易開關，因而(er)使用液壓(ya)(ya)(ya)(ya)閥門(men)來(lai)保持無(wu)塵(chen)(chen)室(shi)內(nei)(nei)(nei)之(zhi)(zhi)微正(zheng)壓(ya)(ya)(ya)(ya)，通過泄壓(ya)(ya)(ya)(ya)風(feng)門(men)的風(feng)量一般(ban)在(zai)100-120m3/h之(zhi)(zhi)間(jian)，保持壓(ya)(ya)(ya)(ya)差在(zai)5-40Pa之(zhi)(zhi)間(jian)。