Abstract: A magnetically-coupled liquid mixer having a drive mount secured to and extending into a mixing vessel, a vessel-external first magnet array adjacent to the drive mount, a stub shaft extending into the vessel and having a first thrust bearing surface, a driven portion rotating on the stub shaft and having radially-mounted mixing blades a subset of which is characterized by each having an opening through which liquid flows during rotation, a second thrust bearing surface, and a second magnet array, the arrays being positioned with respect to one another such that the thrust bearing surfaces are spaced apart at least in the absence of above-threshold fluid dynamic thrust forces on the driven portion, the blade-opening feature introducing increased fluid shear into the liquid.

Abstract: In a magnetically-coupled liquid mixer of the type having a drive mount secured to and extending into a mixing vessel, an external first magnet array adjacent to the drive mount, a stub shaft extending from the drive mount into the vessel and having a first thrust bearing surface, and a driven portion rotatably-mounted on the stub shaft and having a second thrust bearing surface and a second magnet array, the improvement wherein the first and second arrays are positioned with respect to one another such that the first and second thrust bearing surfaces are spaced apart at least in the absence of above-threshold fluid dynamic thrust forces on the driven portion.