Abstract: The mixing impeller of the invention has a central, axial hub adapted for attachment to a rotatable driven shaft of a mixer motor. Mounted on the hub is a disc that extends radially from the hub. Circumferentially spaced around the disc are a number of impeller blades. Each blade has two different surfaces for mixing a liquid. One surface is flat and rectangular; the other surface is arrowhead-like, converging from the axial ends of the rectangular surface toward the middle of the rectangular surface of the next adjacent blade. When rotated at a given speed in a fluid in one direction, the impeller draws considerably less power than when rotated in the same fluid at the same speed in the opposite direction. Under certain operating conditions, the impeller has a higher mass transfer efficiency, in both directions of rotation when compared to other impellers. The blades of the impeller may be either open or closed, thereby further modifying the power characteristic of the impeller.

Abstract: An in-line blender is provided for mixing a single fluid or blending it with at least one other substance. The blender includes a conduit having a hollow interior disposed about a central axis and a shaft extending longitudinally through the conduit along the central axis. The blender also includes a plurality of stationary mixing stages extending in series along the central axis with each of the mixing stages defining a plurality of spiral channels within the hollow interior of the conduit. Each of the mixing stages includes a plurality of distinct segments extending in series along the central axis. The blender further includes means for adjusting both the angular and the axial position of each of the segments with respect to adjacent segments along the shaft.