单项选择题
A.风筒全长的60% B.风筒全长的50% C.风筒全长的40% D.风筒全长的30%
A.5.5kW B.11kW C.14kW D.28kW
A.全风压Pa50~2400Pa,风量225~145m3/min B.全风压Pa25~1200Pa,风量225~145m3/min C.全风压Pa35~2400Pa,风量390~250m3/min D.全风压Pa30~1500Pa,风量112~75m3/min