The Controllable Deformation Dynamic Mixer(CDDM) is a new type of inline rotor-stator mixer developed to give dispersion performance in the nanometric range beyond that of conventional nozzle homogenisers whilst also providing distributive (blending) mixing actions. Resulting from 15 years of research and development by one of the world’s leading fluid processing companies, CDDM is believed to be the highest performance production-scale fluid mixer on the market today. It has been benchmarked against most competitive technologies including nozzle homogenisers and ultrasonic mixers, with superior results. The technology has been fully patented by the originating organisation and Maelstrom is currently the only licensee for the production and sale of CDDM systems in the world.
The major benefits of CDDM technology are:
- Exceptional inline dispersive and distributive performance – best in class
- Efficient multiple-stream blending or dilution
- Back-pressure can be fixed or variable depending on the machine type
- Reliable and scalable for production operations (not just a laboratory instrument)
Note that a restriction on Maelstrom’s license for CDDM technology is that it cannot be used for applications involving personal care products or foods (especially edible fats). If you are interested in CDDM but are not sure if your product would be excluded, please contact us to discuss it.
Principle
The form of the CDDM can be customised to suit individual requirements but normally comprises a cylindrical rotor (which may contain heating or cooling channels) within a cylindrical stator (that may be jacketed for external heating or cooling). The rotor is turned at high speed, usually greater than 3000rpm. As the gap between the rotor and stator is typically 0.01 to 0.1mm, very precise bearings and seals must be used and balance is critical.
A high pressure pump (external to the mixer) forces fluid into one end of the rotor-stator pair. Fluid moves within and between the cavities of the rotor and stator in a similar way to that seen in the FDM, i.e. with “cutting and folding” and turbulent shearing actions for good dispersion and distributive mixing. When the fluid reaches the far end of each rotor-stator cavity pair, it must travel through a very tight gap (nip) in order to progress to the next cavity pair. This nip can be adjusted by altering the relative axial positions of the rotor and stator to obtain a “virtual nozzle” effect. In sophisticated applications, CDDM machines incorporate a mechanism to adjust the nip “on the fly” in real time. Simpler or well-characterised applications, such as those for continuous production, can use less complex CDDM machines with a fixed nip.
The virtual nozzles provide extensional stressing to the fluid in the same way as a nozzle homogeniser. However, as there are multiple nozzles in the CDDM, the effect is multiplied. Key applications for CDDM machines include diluting concentrate streams and blending or reacting multiple input streams under controlled conditions. These make use of the multiple dosing injection points along the stator barrel. High pressure pumps are required to feed each input stream, to overcome the pressure drop of the virtual nozzles.
