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The Expert's Corner

Engineering Excellence: ROSS PreMax Batch Ultra-High Shear Mixer

February 27, 2019

ROSS PreMax with Rotor/Stator assembly

The PreMax`s high-flow design enables product entry from the top and bottom of the rotor/stator assembly. It generates both upper and lower vortexes which allow for extremely efficient powder additions.


  • Fast powder wet-out - no floating powders.
  • Accelerated dispersion or emulsification.
  • Uniform batch temperature.
  • Highly superior dispersions compared to all other batch style mixers including high speed dispersers, traditional rotor/stators and immersion mills.
  • Produces results comparable to one or two passes through a media mill.

Features Include:

  • True "Heavy Duty" Design
  • Inverter-capable, TEFC or XP high efficiency motor. (UL/CSA/EPAct-rated)
  • Control options include: NEMA 1, 4X, or 4/12 Variable Frequency Drive; Explosion-proof Operator Station with On/off Pushbutton, Speed Potentiometer, E-Stop, Digital Amp Meter and Tachometer.
  • Stainless steel anti-rotation bar.
  • Explosion-proof safety limit switches prevent operation of mixer while in the raised position or without a mix vessel in place. (UL/CE/CSA-rated)
  • Heavy pre-drilled base for floor mounting.
  • Air/oil Lift System with ASME CODE pressure vessel and manual controls.
  • Hard-chromed and polished hydraulic cylinder with adjustable and replaceable chevron style packing.
  • Stainless steel 316 wetted parts.
  • Non-stainless steel exterior surfaces are painted with Ross-white, high quality two-part epoxy coating.
  • Stellite rotor shaft bushing (standard). Optional bushing materials are available, i.e. PEEK, tungsten carbide, etc.
  • Patented Delta rotor/stator. Tip speed: 5,000 fpm, Viscosity range: Up to 50,000 cP

Close up Delta rotor and stator

Optional Features:

Temperature Probe A thermocouple can be installed in one of the agitator frame rods. Thermocouple leads are run to a NEMA 12 or 7/9 junction box on the back of the mixer.

Disperser Blade An interchangeable saw-tooth disperser blade can be supplied with the PreMax for operational flexibility.

Vacuum Cover and Vessel A vacuum cover with charge port and mechanical seal mates with a mix vessel and can be supplied with a vacuum pump assembly. Different size vessels are available depending on the PreMax model.

Solids/Liquid Injection Manifold (SLIM) This powder induction system enables operators to add solids sub-surface. Powders are loaded into a hopper (or drawn from the bulk container using a "hose & wand" attachment) and as soon as the Delta rotor reaches operating speed, the SLIM valve is opened to allow the flow of solids into the shear-intense region within the rotor/stator assembly. Powders are quickly drawn into the batch via the powerful vacuum generated by the Delta rotor.

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