US Patent 8146894 Apparatus for mixing gasses and liquids

An apparatus for mixing gas and liquid is disclosed. The apparatus can comprise a draft tube having a gas conduit, a liquid inlet and a gas-liquid outlet, an impeller rotatably mounted within the draft tube. The gas can be entrained into the liquid by rotation of an impeller having relatively high angular velocity, which generates relatively low axial velocity of the liquid and relatively low angular velocity of the liquid. Floats may support the impeller and the impeller may have means for maximizing aeration of the liquid.