Introducing liquids to a powder mixture

"A piece of cake"

Mixing of powders in a batch mixer generally is not so straight forward when compared to the mixing of gasses or liquids. Powders have properties (e.g. cohesive, free flowing or agglomerates) you will not find in liquids or gasses.

Because of these phenomena powder mixtures can be rather complex. Mixing processes where liquids need to be introduced into a powder batch are even more complicated.

For powder mixtures the correct mixing technology needs to be chosen based upon the properties of the powder and the requirements of the end product. Based on these challenges, there is a demand for many different types of mixers for different applications.

The Hosokawa Group has a full range of mixers. The latest development is the Vitomix, a highly flexible mixer, able to combine both gentle and low shear mixing with mid shear mixing (e.g. for reduction of mixing time). With introduction of the Vitomix as a mid shear mixer, the process of the addition of liquids in a powder has become a “piece of cake”.

A piece of cake!

Addition of liquids

The mixing principle of the Vitomix is based upon the Nauta® mixer. However by making use of a different configuration of 2 screws and higher rotational speeds a fluidised bed can be created at the top of the mixer. At this place liquids can be introduced. A perfect ratio between the liquid, powder and air results in a homogene powdery material containing liquid, fat or oils without any lumps. Therefore lump breakers are no longer necessary for breaking up lumps which are normally created with other types of mixers when injecting liquids into powders.

For example the injection of 20% (w/w) of vegetable oil into flour is done within minutes. Also injection of butter (>30% w/w) into bakery products results in a powdery mixture without lumps. Again, all without using of lump breakers. Since lump breakers are no longer necessary, fragile materials are not destroyed or reduced in size. This makes the Vitomix a very interesting option for liquid injection.

Flexible

It requires many different combinations of industrial processes in order to make the products we use every day. For these processes different types of machines are being used. As mentioned in the introduction for powder mixtures the correct mixing technology needs to be chosen based upon the properties of the powder and the costumer requirements upon the end product. Therefore it is possible that after a liquid is introduced in a mixer, using high or mid shear, a second mixing step using low shear (for mixing in fragile materials) is needed, with a different type of mixer. The Vitomix can operate in the mid shear zone but also in the low shear zone. This makes it possible that after the introduction of liquids (mid shear), fragile components can be mixed at low shear without damaging the product structure.

Energy efficient

Another advantage of the Vitomix, besides being able to make liquid/powder mixtures without using lump breakers, are its short mixing times. Due to these benefits, the Vitomix is very energy efficient, compared to other types of equipment used for the same process.

Overall, the Vitomix is a unique machine which combines:
  • The possibility of introducing liquids without the use of lumpbreakers
  • Combination of mid shear and low shear mixing in one machine
  • Short mixing times, also in the low shear zone

» Read more about the Vitomix ribbon screw mixer