For many processing applications high shear mixing has become the preferred solution because it can handle multiple processes in a single operation, whilst reducing mixing times and increasing product quality.
To understand how high shear mixers can do this and how they could benefit your mixing process, it is useful to understand how these mixers work.
What is a High Shear Mixer?
Shear means to cut. A high shear mixer utilises specialized rotor/stator technology to generate extremely high shear rates.
- Rapid intake – The rotor creates a powerful suction effect that continuously draws materials into the high shear workhead.
- Initial Shear – Centrifugal force then drives materials towards the periphery of the workhead where they are subjected to a milling action in the precision machined clearance between the ends of the rotor blades and inner wall of stator.
- Hydraulic Shear – This is followed by intense high shear as the materials are forced, at high velocity, out through the perforations in the stator and circulated into the main body of the mix.
- Complete processing - The materials expelled from the head are projected radially at high speed towards the sides of the mixing vessel. At the same time, fresh material is continually drawn into the workhead maintaining the mixing cycle.
Unlike low shear devices such as stirrers and agitators, high shear mixers actively process the materials in the mix, enabling faster and more consistent results.
How are High Shear Mixers used in the Chemical Industry?
Chemical processing demands consistency under abrasive, high viscosity and reactive conditions. Many chemical formulations are now increasingly complex and as such require a piece of mixing equipment that can complete multiple mixing operations.
High Shear mixers can:
- Accelerate reaction rates
- Create stable emulsions and small particle sizes, every batch
- Maximize yield of active ingredients in chemical suspensions
- Handle high viscosity mixes and effortless blend liquids of varying viscosities
- Ultra fine, uniform dispersion of pigments
- Increase production capacity without adding shifts or staff
- Achieve results in R&D that can easily be replicated at full production scale
Choosing the right mixing solution
Why choose a Silverson high shear mixer over other high shear mixers available on the market?
- Precision and Quality – Silverson High Shear mixers have the tightest shear gap in the industry. If you think of a pair of scissors, a pair with blades close to one another will cut the paper much more efficiently than a pair which has a larger gap. The same applies to high shear mixers. This tight tolerance between the rotor and the stator also allows for more accurate scale-up.
- Trusted by Multinationals – Because of the tight shear gap, Silverson mixers can be relied upon for batch-to-batch consistency, in terms of quality and timings. Looser tolerances means that batch times can vary, even a five minute variation can have a knock-on effect and could consequently end up with fewer batches being produced in a working day. With Silverson, results can be replicated time after time.
- Versatility – Silverson Machines offers the widest capacity range from a single manufacturer, with mixers suitable for processing batches of 1 to 8,000 gallons. Within our range there are many options suitable for chemical processing. A comprehensive range of workheads and screens is available for all Silverson high shear mixers, allowing them to be used for multiple mixing operations.
- Specially designed mixers for the Chemical Industry – designed for aggressive chemical service, the FMX-CD powder/liquid mixer is generally configured to suit specific customer requirements. Double mechanical shaft seals and flange fittings are standard. Elastomers, valve and motor type can be specified to suit the application.
Real solutions for real customers
Silverson Machines have helped thousands of customers all over the world to improve their mixing processes and product quality with the use of High Shear Mixing.
One customer producing printing toner has been able to eliminate their colloid mill with the use of a Silverson In-Line mixer. Although the mill was producing a good product, it was very slow and had a large energy requirement, making it expensive to run and both time-consuming and expensive to maintain.
To improve their mixing process, the company got in touch with Silverson and arranged a laboratory trial. Samples were trialled using an L5M-A Laboratory mixer which produced satisfactory results comparable to the colloid mill, but in a much quicker time. These trials led to the purchase of three In-Line mixers – one for each toner colour – Cyan, Magenta and Yellow.
Mixing times were also reduced for a chemical company switching to Silverson from another high shear mixer manufacturer. By solving their mixing issues with Silverson Machines they have been able to triple their output.
The facility was producing tons of PAM per year for various applications, but they wanted to increase this to keep up with demand. Before purchasing the Silverson In-Line mixers they had been experiencing lengthy processing times along with inconsistent droplet size in their emulsion. With the mixing times being so long, it was not viable for them to try and scale the process. The buyer, who was already familiar with Silverson Machines from a previous position, got in touch to arrange a trial to see if a Silverson mixer could improve the mixing times and quality of the emulsion.
With their previous mixer, it took an hour and a half to complete a batch. Using the In-Line mixer, the desired product was achieved in 20 minutes. The trial Silverson mixer produced a better, higher quality emulsion with a consistent droplet size in a significantly shorter time. Their three new Silverson mixers have allowed them to successfully scale up production and produce their targeted quantity of product with ease in a time much faster than they predicted.
To find out more, visit the Silverson website: www.silverson.com
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