Abstract: An agitator or mixer installed in a solid-liquid-gas/slurry reactor in which gas removal from the slurry and foam destruction is promoted. The reaction mixer includes a vessel and an agitator assembly. The vessel is for containing the solid-liquid-gas mixture and defines two mixing zones within a given volume; a first mixing zone and a second mixing zone located above the first mixing zone. The agitator assembly is positionable within the vessel and comprises a rotatable shaft and a first and second impeller coupled to the shaft. The first axial impeller is locatable within the first mixing zone and is configured to pump the liquid in a downward direction along a vertical axis of rotation. The second impeller is locatable within the second fluxing zone and is configured to pump the liquid in an upward direction along the vertical axis of rotation.

Abstract: A method of mixing paper stock, having improved outlet consistency, includes: (a) feeding liquid and feeding paper pulp into a vessel to form a mixture; (b) providing at least one counterflow impeller that is submerged in the mixture, the counterflow impeller being capable of simultaneously inducing both upward flow and downward flow; (c) rotating the counterflow impeller such that downward flow from the impeller is partially recirculated by upward flow from the impeller to form a mixing zone; (d) sensing a parameter of the mixture discharged from the vessel; and (e) controlling the feed rate of the liquid and the feed rate of the paper pulp in the feeding step (a) based on the sensing step (d). An apparatus for mixing of paper stock, having improved outlet consistency, includes a vessel for containing liquid and paper pulp, at least one counterflow impeller, and a feedback system for controlling outlet consistency.

Abstract: A method of mixing paper stock, having improved outlet consistency, includes: (a) feeding liquid and feeding paper pulp into a vessel to form a mixture; (b) providing at least one counterflow impeller that is submerged in the mixture, the counterflow impeller being capable of simultaneously inducing both upward flow and downward flow; (c) rotating the counterflow impeller such that downward flow from the impeller is partially recirculated by upward flow from the impeller to form a mixing zone; (d) sensing a parameter of the mixture discharged from the vessel; and (e) controlling the feed rate of the liquid and the feed rate of the paper pulp in the feeding step (a) based on the sensing step (d). An apparatus for mixing of paper stock, having improved outlet consistency, includes a vessel for containing liquid and paper pulp, at least one counterflow impeller, and a feedback system for controlling outlet consistency.