How High Shear Mixers Work

Definition of High Shear



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Definition of High Shear

high shear domestic socket A propellor or paddle is often used to mix things, so it is helpful to define high shear mixers by how radically they differ from motorised propellor mixers. If you place a turning propellor in 100L of water then add 10ml of red food colouring and a kilo of garden peas, you will see the red food colouring gradually process through the turbulence and movement, until the water assumes a uniform red colour. At the same time, you will soon see the peas swirling around the mixture, in a reasonably well dispersed manner. Some of the peas may be more buoyant than others and may tend to stay near the surface. Others may sink to near the bottom, away from the greatest turbulence. Few, if any, of the peas will be smashed by the process.

A high shear mixer also creates patterns of flow and turbulence, using an impellor. An impellor is usually blunt and unstreamlined, compared to a propellor. The impellor rotates inside a very close fitting circular wall with evenly spaced small holes in it, all the way round. This is called a stator.

Once the impellor has drawn mixture in, it subjects it to a sudden change of direction, often approaching 90 degrees, hurling it against the wall with centrifugal force. It is either dashed against the stator, causing another brutal change in speed and direction, or is forced through the holes in the stator at great pressure and speed, in a final disintegrating change of direction and acceleration.

As a result, various molecules within the mixture are travelling at very different speeds to neighbouring molecules, tearing them away from each other and generating considerable friction. This tearing is called high shear and it often generates a significant amount of friction, as the molecules rub past each other. This friction generates heat. In some applications, a few molecules may heat up by hundreds of degrees for a few microseconds, before being rapidly cooled by the main mix.

This is why you will sometimes find that your mixture temperature rises by a couple of degrees, during the course of the mixing process. Needless to say, your peas are reduced to a fine cloud, suspended in your mixture. A high shear mixture works differently from a kitchen blender, which uses sharpened blades, but it will often have a similarly destructive effect. This is why high shear mixers are commonly used to dissolve large amounts of table salt or crystalline sugar, into water, at room temperature.

RAREL Rules High Shear Mixers as Industrial Blenders

Kitchen blenders have become more powerful over time and the best can disintegrate chicken bones, releasing the marrow inside for culinary use. Even the best kitchen blenders cannot do this for long before the blades become blunt, consigning the blender to landfill. Our mixers disintegrate hard lumps over long periods and on a large scale, before you need to buy replacement parts.

By large scale, we mean 25 to 250 litres. This is large for a kitchen but small by the standards of many established factories. This makes RAREL Rules ideal for start-up companies and localised rural entrepreneurs. This limit keeps the machine compact and very affordable for new businesses, whilst being relevant to the needs of many laboratories.

Why is RAREL Doing This?

We believe that more fuel, more food and more manufactures should be made locally.

RAREL High Shear Applications

It is very easy to bolt your own unique accessories to our unit. It is a highly versatile unit which invites Builder Owners to take the design even further.

Small businesses and entrepreneurial individuals, will value our affordable approach - but that alone is not enough. Our machines need to be easy for people to change and adapt to the unique conditions in their workshops and micro-businesses. One of our Alpha Sites, for example, is running a pump from the main shaft of his RAREL Rules mixer.

We spent several years (or rather Nessy did) talking to people who wanted to start a business, or expand a business in their homes. In this role, Nessy found that her mixer needed to be between 2 and 4 horse power and single phase, so as to plug into domestic electricity sockets. She also decided to accommodate variations in voltage and frequency between countries.

Over those same years, Nessy identified several core applications that she wanted her high shear mixer to support, in its standard form. For more information about some of those applications, click on the button marked "Applications" to the left.


We deliberately have not patented our mixer. This reduces the cost to you, because you neither pay for our patent attorneys and agents, nor do you fund a war chest to help RAREL fight patent infringements. And competitors will only copy our products, if they believe they can sell them to you even more cheaply than we can.

One of the consequences of this is that we do not publish technical data that might be useful to a competitor. We have no intention of making it EASY for competitors to enter the market with inferior copies of our machines.

However, all the data you need to make an initial assessment of our technology, is freely available under the button marked "Technical" to the left.

Builder Owner Manual or BOWMAN

Without the BOWMAN, you cannot build your own high shear mixer. The Bowman will talk you through the process of buying standardised components from approved stockists and will then show you how to bolt the components together. To read about all the other information provided by the Bowman, click on the button to the left marked "Bowman".

Access to the Bowman Via The Beta Site Program

Although the Bowman will soon be available on Amazon and eBay, for the time being and for the duration of Beta Site Testing of the Bowman, the Bowman will only be accessible via an application to join the Beta Site Testing Program. The eBay and Amazon price will be £277. The discounted Beta Site price is a nominal £50, because it implies site visits by RAREL engineers, who will be keen to talk to you, as well as to take photographs of your own trials of the RAREL machines they bring with them. To learn how to apply to join our Beta Site Testing Program, click on the button marked "Beta Site" to the left.


RAREL aims to enable you to build your own world class high shear mixer for under £4,000. To see how the sums work out in these early days of production, click on the button to the left marked "Money".

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