An apparatus includes a body having a central axis, a fluid inlet coupled to the body, the fluid inlet being adapted to receive a flow of a fluid, and a fluid outlet coupled to the body. The fluid inlet and the fluid outlet are substantially coaxially aligned so as to define a flow axis through the apparatus, and the flow axis is laterally offset from and perpendicular to the central axis of the body. A rotating blade assembly is disposed within said body and includes a plurality of blades, wherein the rotating blade assembly is adapted to be controllably rotated about the central axis so as to control a fluid level of the flow of fluid entering the fluid inlet.