Multi-shaft mixers with solids/liquid injection manifold (SLIM) technology from Charles Ross & Son Co. reportedly enable fast and efficient large-scale powder dispersion into low-viscosity liquids, including resins, oils, melted waxes, emulsions, and aqueous solutions. The pictured VersaMix Model VM-600 is a 600-gal capacity dual-shaft mixer designed for deep vacuum levels. Featuring a high-shear mixer with SLIM technology, the rotor/stator assembly of the VM-600 creates a powerful suction that draws solids sub-surface, directly into the high-shear zone. This method of material addition accelerates powder wet-out and minimizes issues like agglomeration (fisheyes), floating powders, and dusting.

According to the company, the second agitator is a two-wing anchor equipped with hinged Teflon scrapers for consistent heat transfer across the vessel sidewalls and bottom, which could be jacketed for temperature control. After the powder induction step, the VM-600 can handle a significant increase in viscosity because the combined mixing action of anchor and high-shear mixer ensures adequate turnover. The finished product may take on the consistency of a thickened gel, paste, or slurry. The Ross VersaMix can be supplied with a third agitator, such as a sawtooth disc blade or a screw auger.

Operated from a 15-in. HMI touchscreen with a customizable recipe system, Ross reports that this mixer allows for accurate and efficient batching based on speed, time, temperature, and vacuum pressure. Additional functions programmed into the mixer control panel include digital valve controls, printing of batch ticket, and interface with pumps and load cells.

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