Patent ID: 8544827

Claim:
A mixing system comprising: a mixing tank having a bottom, sides and a top; a double channel central draft tube; a pump forcing an inlet fluid downward through a central channel in the double channel central draft tube; said central channel having a primary nozzle facing downstream; an outer draft channel housing the central channel; wherein an annular space between the outer draft channel and the central channel forms a secondary channel; said outer draft channel having a secondary nozzle facing downstream; wherein said primary nozzle is located above said secondary nozzle, and both nozzles share a common longitudinal axis; said outer draft channel having an inlet weir for channeling a mixing tank fluid into the secondary channel; wherein the pump has a variable flow rate controller; wherein said variable flowrate forms a vacuum at a bottom end of the outer draft channel; wherein said vacuum induces the mixing tank fluid into the weir and out the secondary nozzle at a low flowrate setting of the controller; wherein a combined flow from the primary and secondary nozzles impinge the bottom of the mixing tank; wherein said outer draft channel is connected to the central channel, and the connected channels are fastened to a ballast tank so as to float both channels up and down; said central channel having an upper slip tube to maintain a fixed location top end to the central channel; and wherein a high flowrate setting of the controller lifts the inlet weir above a fluid surface, thereby sucking air into the inlet weir and emptying the secondary channel to provide an air and fluid combined flow from the secondary nozzle.