Mixing apparatus

Claim 1

A mixing apparatus for mixing two liquids, comprising: a base plate; a vertical cylindrical shell mounted to the base plate and enclosing a mixing space therein; a cylindrical shroud vertically mounted on the base plate in the shell with an annular outer riser chamber between the shroud and the shell, and having an upper end terminating below the upper end of the shell; first and second inlet means each directing a stream of a respective one of the liquids into said shell substantially tangent to the inner wall thereof and the outer wall of the shroud so as to move upwardly through the outer riser chamber and at the same time to mix the liquids, outlet means for withdrawing a mixture of the liquids from the mixing space; a central tube carried by the base plate, said central tube having a longitudinal bore therethrough communicating with the outlet means; an inverted tube mounted intermediate the shroud and the central tube to define a downcomer passageway between the shroud and the inverted tube and an inner riser chamber between the inverted tube and the central tube, said inverted tube having a lower end terminating above the base plate and an upper end terminating above the upper end of the shroud, said downcomer passageway having opposite ends in fluid communication with said outer riser chamber and said inner riser chamber, and said inner riser chamber being in fluid communication with said bore; recirculation means for withdrawing a portion of the mixed liquid from the downcomer passageway and directing the said portion to the outer riser chamber; and wherein the recirculation means comprises a plurality of apertures extended through the shroud and opening to the outer riser chamber, said apertures being located below the lower end of the inverted tube.