Patent ID: 7083324

Claim:
An apparatus for mixing a fluid within a tank, the apparatus comprising: a beam pivotally supported at a fixed pivot support, the beam movable in cyclic tilting motion such that ends of the beam move vertically in mutually opposing directions; the ends of the beam pivotally engaging vertical elongate arms depending downwardly therefrom, the elongate arms executing primarily vertical motion; each elongate arm downwardly terminating and engaged with a plurality of vertically spaced-apart mixing plates oriented orthogonally to the elongate arm and orthogonally to the motion of the elongate arm, each of the mixing plates providing radially oriented fins; the mixing plates immersed within the fluid and providing apertures therein for conducting the fluid between the plates so that the mixing plates cause fluid mixing as the beam moves in the tilting motion; a means for causing the beam to execute cyclic tilting motion; and a fixed film biomass engaging the plurality of plates for biologically processing the fluid in the tank, wherein the unbalancing means is a weight moving cyclically along the beam from one side of the pivoting means to another side of the pivoting means thereby causing the tilting motion.