FAN AND SHROUD ASSEMBLY FOR REDUCING NOISE THROUGH AIR FLOW BY APPROPRIATELY DESIGNING OVERLAPPED RATE BETWEEN TIP OF BLADE IN AXIAL FLOW FAN AND CYLINDER IN SHROUD

摘要

PURPOSE: A fan and shroud assembly is provided to increase the radiant efficiency by overlapping a barrel portion and a tip of a blade at a certain rate. CONSTITUTION: A housing of a shroud has a cylindrical barrel portion(44) and a bellmouth type intake portion(46). The barrel portion is arranged in a downstream against a tip(36) of a blade. The intake potion is expanded frontward from the tip of the barrel portion at a certain curvature radius. An overlapped rate between the tip of the blade and the barrel portion is represented as the height of the tip divided by the height from a rear end(38) of the tip to a boundary portion(48) between the barrel portion and the intake portion and to be multiplied by 100. The overlapped rate is from 30% to 60%.