為了防止(zhi)無塵(chen)(chen)室(shi)(shi)受(shou)到污(wu)染，室(shi)(shi)內(nei)必須保持(chi)(chi)正(zheng)壓，如果無塵(chen)(chen)室(shi)(shi)內(nei)壓力過(guo)高，造成門扇(shan)不易開關，因而使用液壓閥門來(lai)保持(chi)(chi)無塵(chen)(chen)室(shi)(shi)內(nei)之(zhi)(zhi)微正(zheng)壓，通(tong)過(guo)泄壓風門的風量(liang)一般(ban)在(zai)100-120m3/h之(zhi)(zhi)間，保持(chi)(chi)壓差在(zai)5-40Pa之(zhi)(zhi)間。