Patent ID: 6042335
Filing Date: 2000-03-28
Classification: F04D

Abstract:
A centrifugal flow fan, comprising:(a) a fan hub lying generally in a plane normal to the axis of fan rotation, and having a central opening for receiving a motor housing;(b) a plurality of fan blades of substantially identical construction spaced circumferentially evenly around said fan hub and extending away from said fan hub in a direction parallel to the axis of fan rotation, each fan blade having(i) a radially inner portion,(ii) a radially outer portion,(iii) a maximum height, Hb, measured at a boundary line separating said radially inner portion from said radially outer portion,(iv) a leading edge at its innermost radial periphery, the leading edge, at least at the axially upper one-half section of said radially inner portion, being convexly curved in the shape of a quarter ellipse having a major axis, Mg, substantially parallel to the axis of fan rotation and a minor axis, mh, normal to said major axis, wherein Mg/Mh=1.25 to 1.5, and(v) a substantially linear trailing edge at its outermost radial periphery; and(c) a continuous shroud joined to each fan blade at an axially upper section of said radially outer portion thereof, said shroud being concave in cross-section, the fan having an outer diameter, D, Mg/D=0.25 to 0.4 and Mg/Hb=0.4 to 0.6.