The present invention relates to a mixer and methods of mixing and, more particularly, to a mixer and mixing methods that provide a multi-direction, angular, non true circular movement pattern creating a circular type flow capable of mixing and maintaining homogeneity in the product being mixed.
Mixers generally “pump” product within a confined area to mix product additions and maintain homogeneity. Mixers currently available on the market include standard tank mixers with propellers and single-use (or disposable) mixers. Most standard tank mixers are of the top-entering type and include a rotating shaft entering from the top into a tank where mixing occurs and an impeller attached to the rotating shaft for mixing purposes. Bottom magnetic type mixers can perform mixing without intrusion into the tank but have an impeller/bearing assembly in contact with the product. Other standard tank mixers provide a simple back-and-forth motion for mixing. Single-use, top-entering type mixers normally include a shaft/blade that provides a simple back-and-forth or oscillating motion. A flexible boot in a top of a bag allows entrance and containment of the shaft/blade. The shaft/blade is sometimes covered with a bag so that there is no product contact or intrusion into the product. As for a single-use bottom magnetic/levitating mixer, a single-use blade is located inside the bag and basically operates in the same concept as standard tank mixers. However, the shafts/blades of all conventional mixers can not always provide homogeneity in the product.
In an approach to provide more homogenous mixing, the mixer includes a continuously rotating mixing paddle which is subjected to both rotative and swingable oscillation about a transverse axis to produce a non-repeating, spherically-orientated mixing path resembling a series of radially-disposed overlapping lobes. In another approach, the mixer includes a non-rotating elongated arm extending through an opening in the top of a tank, with the arm pivoted for movement about a pivot axis. Furthermore, an impeller is positioned on the arm for movement therewith and within the tank, with the impeller moving back and forth along an arcuate path within the tank as the arm pivots back and forth about the pivot axis. Further, a ball-and-socket assembly is positioned above the top of the tank and movable along a curved path to move the impeller in a curved path within the tank. However, the mixing results of these two approaches are still unsatisfactory.
Thus, a need exists for a mixer that provides a movement pattern creating a circular type flow capable of mixing and maintaining homogeneity in the product being mixed.