Patent Number: 6,250,797

Title: Mixing impeller system having blades with slots extending essentially all the way between tip and hub ends thereof which facilitate mass transfer

Abstract: An axial flow mixing impeller system for efficient mass transfer by control of size of the bubbles of the fluid which is being dispersed, especially gases and liquids with viscosities greater than the liquid into which dispersion occurs, is obtained by creating passageways through the impeller blades for flow between the suction and pressure sides of the blades which disrupts the flow over the suction sides of the blades thereby reducing the tendency for bubbles to grow or coalesce into large bubbles which instead of being dispersed, rise to the surface without effective mass transfer to the liquid which is pumped by the impeller. The blades of the impeller may be slotted inwardly from the tips thereof to provide the passageways or may be formed from segments, gaps between which provide the flow passageways. The segmented blades have the advantage of enabling systems of large diameter impellers, of size approaching the diameter of the tanks or in closed tanks where access is by way of a manway smaller than the impeller blade dimensions, to be assembled within the tank, either upon initial installation or for replacement or retrofit. If the system is not used for gas or liquid dispersion, the segments may be in edge-to-edge abutment. Gas-to-liquid dispersion may also be improved by sparging below the impeller at the bottom of the tank and between the impellers in the tank, as with sparge rings of diameter less than the diameter of the impellers enabling gas supply at different pressures commensurate with the depth of the sparge rings, sufficient to overcome the head at the depth of the sparge ring.

Inventors: Weetman; Ronald J. (Rochester, NY)

Assignee: General Signal Corporation

International Classification: B01F 3/04 (20060101); B01F 15/00 (20060101); B01F 7/22 (20060101); B01F 7/16 (20060101); B01F 7/00 (20060101); B01F 007/22 ()

Expiration Date: 06/26/2018