“The Dispersion of Difficult Products & Ingredients”

The fluid mixing spectrum is represented by a broad range of applications involving physical or chemical processes with a wide variety of mixing equipment applied to them. The individual processes may be flow controlled or shear controlled. Knowing the controlling mechanism and the best technology to achieve the desired process result is our specialty.

Quadro Engineering Incorporated specializes in technologies for the mixing and dispersion of difficult products and ingredients. In general, we classify these applications as follows:

1. Missible Liquid/Liquid applications are blending jobs and are flow controlled. On most of these applications, conventional, open impeller, slower speed mixing technologies will be the most cost effective choice. There are a large number of suppliers in this spectrum and Quadro prefers not to offer equipment for these applications.
2. Liquid /Solid – solids suspension applications involving the physical process of suspending solid particulate to vary degrees in a liquid medium. On most of these applications, conventional – open impeller, slower speed mixing technologies will be the most cost effective choice. There are a large number of suppliers in this spectrum and Quadro prefers not to offer equipment for these applications.
3. Gas/Liquid applications involving the dispersion of an introduced gas into a liquid medium. The objective is to achieve a fine bubble dispersion to maximize the surface area of the gas/liquid interface thus ensuring good transfer of the gas into solution. Although the actual dispersion is a physical process, the adsorption of the gas into solution and subsequent reacstions (if any) are chemical in nature.
4. Immiscible Liquid/Liquid applications, such as oil and water dispersions, can be handled very well with Quadro mixing technology. This is a dispersion type of application whereby a certain amount of shear is required to adequately disperse one liquid into another, thus creating an emulsion. Recirculation rates and the developed shear stress result in a balance of dispersing and coalescing rates. A stable dispersion is called an emulsion, and will usually involve a surfactant and a high shear device.
5. Liquid/Solid Dissolving application involve the physical steps of wetting and dispersion, and the chemical step of dissolving. The dissolving step is dependant on a rate constant (function of product solubility and temperature), the interfacial area and the concentration gradient.
6. Liquid/Solid Dispersing applications involve the physical steps of wetting and dispersion. The ultimate particle (agglomerate) size is reached when the inter-particle attracting forces equal the shear stress produced.

In application (5) and (6) above, conventional mixers and many other high shear devices casue the powders to wet out without difficult thus forming large pumps or commonly referred to as “fish-eyes”. “Fish-eyes” are lumps of product with a hydrated outer skin but an unhydrated, or dry, core. The available shear with these devices is usually ineffective ar dispersing these lumps. Very often the result is damaged and/or wasted ingredients as well as excessive batch times.

“Liquid Mixing Terminalogy”