More efficient mixing

Jon Lawson

Vincent Fleck details a solution for mixing big vessels better and more cost-effectively

In the last issue of this publication, we reported for the first time about a new up/down moving mixing system – instead of the usual rotating agitators. Since then, it has become clear that this new solution has the potential to become a very good friend of many a process engineer.

When mixing is the process of thoroughly combining different materials to produce a homogenous mix, it is really a critical process step and is in part responsible for the quality of the final product.  Success here has a lot to do with mixing performance, i.e. consistency in the solid contents and distribution, low shear by gentle product handling, mixing at low energy rates. With the Flecks Mixer solution, half of the work is already being done free of charge by gravitational force.

On the other side of the mixing equation, poor mixing with non-homogenous product lacking consistency in chemical composition, colour, flavour and reactivity creates big costs.

The efficiency of today’s agitators/mixers is compared by two main characteristics: thrust (N) being its output, and its electrical power consumption (kWh) being the main part of the lifecycle cost.

The Flecks Mixer’s efficiency is clearly defined in an example of a 50m3 tank with suspended matters by the thrust of 40,000N and the energy demand for the related compressed air requirement of two movements per minute (for the pneumatic cylinder) of 9kWh. This results in a specific thrust efficiency number of 4,500N/kW in this example.

Applications of the new mixer

There are a number of industrial applications that are the perfect for for the Flecks Mixer. Firstly is in brewery applications, such as mashing in of dry malt grist, wettening the particles, off-bottom particle suspension and quick/constant homogenisation of temperature with low shear force.

Next is the booming fermentation industry. Here, the product is used for low shear mixing in segregating fermentation broths.

The paper industry is another sector that is embracing the new solution. Coating kitchens in paper and paperboard factories are a natural habitat for the Flecks Mixer. Such kitchens are where paper is usually given an additional coating – where a special gloss, structure or specific effect is added. High-quality coaters contain pigments, binding agents and auxiliary agents. Flecks Mixer can be used successfully for these kinds of fluids and will achieve homogenous mixing of the components, which is an important requirement for any coating colour processing system.

Any processing industry can gain profit by adopting this new solution. As simple as it sounds, avoiding the segregation of hotter and colder processing water in preparation tanks saves money. Optimising the solids flow in slurry reactors or storage tanks is another advantage. Faster heat transfer in reactors leads to decreased blending times. Finally, the mixer enables faster determination of the right temperature, pH, etc.

In its own testing plants (50 litres and 500 litres) Flecks Mixer can engineer the right solution for each application and demonstrate the advantages of the system.

The high efficiency of the new mixing system is combined with a fairly low investment cost, a robust design suitable for industrial applications and can be applied in any existing tank that is suitable for top entry. In short, Flecks Mixer provides a reliable homogenisation at low shear force for high-quality media.

Vincent Fleck is a biotechnologist and head of Flecks Mixer.

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