FDM High Shear Technology

Fluid Division Mixing (FDM) is a patented rotor-stator mixing technology that behaves as a high shear mixer when operated at high speed and as an ultra low shear mixer when run at low speed.

In high speed (high shear) mode, FDM machines take advantage of inter-cavity transfer and hydraulic shear forces to deliver mixing performance that is typically 25% higher than other rotor-stator high shear mixers. The unique geometry and form of FDM mixers provide a number of other benefits in many powder dispersion and emulsification applications, including:

  • relatively large rotor-stator gap – tight clearances are avoided, simplifying maintenance and improving long-term reliability.
  • improved cleanability – the technology allows good access behind the rotor for cleaning and inspection for critical food and pharmaceutical applications
  • robust construction – the geometry allows solid rotor and stator parts which are less vulnerable to damage
  • the energy transfer primarily results from fluid shearing on itself, so particles contained within the fluid are impacted against each other rather than against the mixer surface. This gives improved particle size reduction and reduces the amount of wear on the mixer surfaces.
  • all of the material going through the mixer is forced to participate in the high shear action, giving much more consistent results per pass when compared to conventional machines where much of the fluid may bypass the high shear zone.

Geometry & Operation

FDM is a concentric rotor-stator system with indentations or cavities machined into the rotor and stator surfaces. The cavities in the rotor and stator are typically spherical segments which are open on both vertical and horizontal faces. The rotor and stator are based on a stepped conical form so that the diameter of the cone increases from inlet to outlet. This increasing diameter provides a centrifugal pumping effect.

Fluid moving from inlet to outlet through the mixing head is driven both axially and radially by the pumping and rotational forces generated by the rotor component. As fluid enters the mixing head, it fills the first paired rotor-stator row of cavities. The motion of the rotor initiates spin in the fluid within the cavities and the direction of spin in the rotor cavities is opposite to that in the stator cavities. The fluid vortices formed by this action collide with one another, imparting hydraulic shear. It is this shearing action that transfers energy to the fluid for particle and droplet size reduction. An additional effect of the contra-vortex motion of the fluid is intimate microscopic-scale blending. This helps with rapid and complete powder dispersion in liquids.

Performance

With up to 25% higher mixing energy than typical rotor-stator “high shear” mixers, FDM machines can deliver spectacular results, fast.

Rapid power dispersion into liquids and fine emulsions in the <5 micron range are the norm from laboratory scale to batch quantities of up to 100,000 litres or continuous flowrates of 200,000 litres/hour.

With impressive results and the benefits of a unique geometry, FDM offers a huge step forward in high shear mixing.

Fluid Division Mixing (FDM) is a patented rotor-stator mixing technology that behaves as a high shear mixer when operated at high speed and as an ultra low shear mixer when run at low speed.