The efficiency of prismatic blade equipped on the traditional machine is only 62 % , but the efficiency of the energy saving induced draft fan whose impeller and blade are both stamping is 85 % 传统磨粉机上配用的直叶片老式风机的效率仅为62 % ,而叶轮与叶片均为模具冲压成型的节能引风机的效率为85 % 。