|1. Preblend and
|2. Why to preblend
|3. How to preblend ?
|4. Mixing quality required
Preblend and premix are very widespread in the powder industry, many processes are actually using some of the materials required for the dry mix as preblend or premix.
A preblend, or premix, is made of several constituents that have been mixed together in advance. The resulting mix then becomes a single ingredient, the preblend or premix, when dosed to the final mixing step of a process. Preblend are typically made of one or several small ingredients mixed with a major ingredient, called the carrier.
The terms preblend and premix are often confused and used one for another. Sometimes the following distinction is made : a preblend will designate a mixture done on site by the same manufacturer of the final product while a premix will designate a mixture done by another supplier and bought by the manufacturer of the final product.
Preblending is an additional process step which in appearance brings complexity. Why not simply mix all component together in a single mixer ?
There are actually 2 main reasons to decide to make a preblend or a premix :
5 Most Popular
1. Pneumatic transport design guide
2. Ribbon blenders
3. Powder mixing
4. Hoppers design guide
5. Measuring degree of mixing
Top 5 New
1. Continuous Dry Mixing
2. Mixing speed
3. Mixer cycle time optimization
4. Batch / continuous mixing comparison
5. Energy Savings
A preblend is done prior to the final mixing step. Many industrial setups can be found within the bulk solids industry, but the following are the most common :
Preblend are to be dosed in a main mixing step, the homogeneity required for the preblend is therefore usually less stringent than the main mix requirements. The homogeneity target for the preblend will depend on the quantity finally dosed. The higher it is, the lower the mixing quality needs to be (or higher the CV target). It is understandable as, even if there are some in-homogeneity in the preblend, the larger portion of preblend is dosed, the more change there is to have the right quantity of components in the quantity dosed.
It is often necessary to dilute the small ingredients constituting the interesting part of the preblend by another constituent that will come in much larger quantity and will thus allow to have significant enough weight of preblend to be dosed in the final step. This larger constituent is called a carrier and can be, in the example of food industries, sugar.