Ten top tips when selecting mixers for powder blending

Mixing or blending of powder ingredients is a very common industrial process practiced in many industries including chemicals, pharmaceuticals, plastics, minerals, metals and food. The choice of mixer is extensive and can be confusing. These ten top tips may help in narrowing down the final choice.

1.  Batch or Continuous

One of the first questions to address. Here we look at considerations for selecting the right equipment for batch mixing. In batch mixing the whole batch can be identified and is traceable to help with overall quality control. Batch operations are very versatile and one blender can be used for multipurpose operations and for blending several ingredients together.

2.  Batch size

Don’t assume biggest is best! Some mixer designs may not achieve a full homogeneous mix when the volume is large or the mixing time is extended.

3.  Mixing time

The shorter the mixing time to achieve an homogeneous mix then the lower the costs will be and there will be less product degradation with sensitive materials. Look for efficiency in blending operations with gentle actions. Hosokawa has a wide range of mixers that meet this requirement.

4.  Power consumption

Energy efficiency is a vital factor these days and not just the installed motor power but the actual power used in blending. Some, such as the iconic Nauta Conical Screw Mixer only mix small portions at a time while the mixing arm rotates throughout the mass. These have very much lower power loads.

5.  Ease of discharge

The discharge of a batch blender is one of the most critical functions and here it is necessary to ensure that the blender empties fully and smoothly with no residual ‘heel’. Check the discharge opening size as many blended powder products can be a little sticky and have poor flow properties.

6.  Internal finish

Smooth internal finishes to the mixer are always best as this aids discharge. In the food and pharmaceutical fields stainless steel vessels are common.

7.  Ease of cleaning & cross contamination

This is very important particularly when one mixer is to be used for different products. If cleaning is highly critical, for example in the food and chemical field, then CIP or even SIP can be installed.

8.  Know your target result

It is important to know a clear end result specification so that mixer manufacturers can best advise on the type of mixer best suited to your requirements.

9.  Factory space

Fairly obvious but something that needs to be considered carefully. Not just the actual space for the mixer but any access requirements for loading and discharge and cleaning. Ceiling height can often make mixer selection a little more complex.

10.  System design

It is never too early to consider the design of the total system when making your mixer selection. For example there would be no point in opting for high accuracy blending equipment if you are then planning on blowing discharged product a large distance across the factory, thereby allowing it to segregate.

When selecting a mixer, it pays to talk to the experts to prevent costly mistakes which can affect the mixing result which further impacts on next stage processes and final product quality. Hosokawa engineers are able to help with this crucial advance system planning as well as advice on the right specification mixer for your needs.