MIXING SYSTEM FOR LIQUIDS HAVING FIBRES SUSPENDED THEREIN:CONFIGURATION OF BLADES IN BLADED AXIAL FLOW IMPELLER IN DRAFT TUBE

摘要

Mixing systems for liquids having fibers suspended therein wherein the fibers tenaciously adhere to and accumulate on the leading edge of an impeller (30), thereby increasing the drag of the liquid on the impeller (30) as it rotates and the consequent increase in the power required to rotate the impeller (30), is reduced. Axial flow of the liquid in a tank (10) is produced by the impeller (30) within a draft tube (12). The leading edge (38) of the blades (32) of the impeller (30) are inclined with respect to radial lines (60) extending from the axis of rotation (56) of the impeller (30) beyond the angle of repose of the fibers on the leading edge (38). Also, the coefficient of friction of the portion of the impeller (30), extending from the leading edge (38) toward the trailing edge (40) thereof, to which the fibers adhere is reduced by providing the surface thereof with a low coefficient of friction material (50).