High Shear Mixers

How to Select a High Shear Mixer
High Shear Mixer selection can be an involved process. Many designs are available, in batch and inline configurations. Choices within these categories range from simple High Speed Dispersers to complex Multi-Stage Ultra High Shear designs.

To learn more we suggest that you start with a review of the attached article "High Shear Mixing" Don't Fall Victim to Common Misconceptions. This article reviews the selection process, scale up and provides useful and practical technical information.

High Shear Mixing - Don't Fall Victim to Common Misconceptions

Batch Rotor-Stator Mixer Flow Pattern

Single Stage Rotor/Stator design
Available in either batch or inline, and in standard or sanitary designs to meet the exact needs of your process.

Ross HSM-100LSK-I Laboratory Mixer
Ross HSM-100LCI-I Laboratory Mixer

Flow Pattern
As illustrated on the right, fresh materials are continually pulled into the rotor/stator interface. They are then expelled out of this area, and recirculated if a batch system, or pumped downstream when using an inline design

Our batch designs can be permanently mounted to the mix tank or suspended over the vessel using a portable or permanent lifting mechanism. When supplied with a portable/mobile lifting mechanism, you can enjoy the use of the mixer in multiple mix vessels and also in different areas of your manufacturing plant. Whether the lift is portable or fixed, you are able to vary the position of the agitator within the vessel, to fine tune the process and to handle a wide variety of materials.

The Inline design consists of a single stage rotor that turns at high speed within a stationary stator. As the rotating blades pass the stator, they mechanically shear the contents. The Inline model is a good choice for process lines that require frequent changeover from one product to another. A simple valve can divert finished product downstream or switch instantly from one vessel to another.

Rotor/Stator Mixers are generally applied on products that are up to approx. 10,000 cps. The four-blade rotor of the standard design turns within a close tolerance stator at roughly 4,000 fpm. The higher energy units can rotate at speeds over 16,000 fpm and offer end results that are sometimes equal to or better than a conventional homogenizer. The rotor-stator mixer is great for applications that require fast particle size/droplet reduction. Homogenization, solids size reduction, emulsification, are perfect applications for this versatile mixer. Numerous sizes are available from 1 through 250 hp.

Selection of Rotor/Stators

  • Round - Round holes for dispersion applications
  • Slotted - Slotted for fine dispersions and size reduction of solids
  • Square - Large square holes for high flow rates/size reduction
  • Fine Screen - Fine screens for fine emulsions.

  • HSM-100LCI-T Laboratory High Shear Mixer

    HSM-100LH-3 High Speed Disperser

    Multi-stage designs

    Double & Quad designs
    This seriies includes two or four rows of rotating blades that nest inside a matching stator. The mix material enters through an inlet connection and is accelerated outward by centrifugal force. During each transit through the rotor-stator, the material is subjected to a succession of increasingly intense shearing events -until it finally exits downstream, or is recirculated for another pass through the mixer. Uniform droplets below 1 micron are possible using these designs.

    Low Profile X design
    The X-Series rotor and stator is comprised of many concentric rows of intermeshing teeth. Tolerances are very close, and the shear rates are extremely high. This unit operates at tip speeds up to 18,000 fpm. The X is a great choice for emulsions and dispersions that would otherwise have required more expensive homogenizers or colloid mills.

    MegaShear design
    The MegaShear rotor and stator is of a unique design, consisting of opposed, semi-circular, cylindrical grooves that are machined on both the rotor and stator faces. When a fluid is exposed to these opposed partial cylinders, a counter-flow is induced which splits and redirects the flow of the fluid upon itself to create an extremely high-turbulent collision phenomenon.

    High Speed Disperser Flow Pattern High Speed Disperser
    High Speed Dispersers consist of a driven vertical shaft and a high shear disk type blade.

    Flow Pattern
    The blade rotates at up to 5000 fpm and creates a radial flow pattern within a stationary mix vessel. The blade creates a vortex that pulls in the contents of the vessel to the blades sharp edges. The blade surfaces then mechanically tear apart solids thereby reducing their size, and at the same time dispersing them among the liquid used as the carrier fluid.

    High Speed Dispersers are ideal for dispersions that are up to a maximum of approx. 50,000 centipoise. When used in conjunction with Multi-Shaft Mixers, they can be useful to several hundred thousand centipoise. Most are supplied with air/oil hydraulic lifting mechanisms to enable their use with multiple mixing vessels. Fixed tank designs are available, and both can be supplied for either vacuum or pressure operation.

    Dispersers are available from bench top sizes to very large production sizes capable of dispersing several thousand gallons at a time.

    PreMax Rotor-Stator Mixer Flow Pattern PreMax Rotor-Stator Mixer Flow Pattern

    The PreMax is a single stage rotor/stator generator specially contoured to generate high shear and vigorous flow in a batch mixing environment. The Delta rotor/stator of the PreMax is designed to produce an intense combination of mechanical and cavitational shear, which results in aggressive pigment deagglomeration. This high shear mixer can reduce the number of passes required through a media mill during pigment dispersion, thereby reducing costs and speeding up production. The PreMax is ideal for flexo, gravure and offset inks, paints, industrial coatings, electronic inks and cosmetics.

    Flow Pattern
    The PreMax rotor-stator generator draws materials into the high shear zone from both above and below. This promotes fast wetting and deagglomeration as well as vigorous flow, both radially and axially.