Rapid-mixing granulator is used in pharmaceutical industries for the pre-mixing and kneading steps of tablet manufacturing.
How much powder can be mixed or wet in the RMG or a rapid mixing granulator depends on the capacity of the RMG.
The majority of the people working in pharmaceutical industries take the capacity of rapid mixing granulator in kilograms but the correct practice is to take the capacity of RMG in litres.
To understand why we take capacity in liters read the following article.
For brief overview the main logic to take capacity in liters is that it varies depending upon the bulk density of materials.
How to Get Capacity In Liters
The capacity of RMG is mentioned on the equipment or you can find out the capacity in liters mentioned in the equipment manual provided by the manufacturer.
For old equipment if you don’t have a manual or if there is no data provided by the manufacturer then you can find out by filling the RMG with water till it’s brimful.
You can use a flow meter to measure the amount of water in a rapid mixing granulator or can manually add water with the help of a calibrated container.
Calculation
Suppose we want to calculate how much quantity of product ‘A’ can be mixed in a rapid mixing granulator and we have the following data
RMG capacity = 500 liters
Product bulk density = 0.6 g/ml
We will use the following formula
Capacity of RMG litres × Bulk density of the product
Put the values
500 × 0.6 = 300 kg
So we can add 300 kg of the product ‘A’ having a bulk density of 0.6 g/ml till its brim but in real practice, we take 70 to 80% of the total capacity and leave some space for mixing & it is known as working capacity so if we take 75% then,
300 × 75/100 = 225 kg.
So the working capacity will be 225 kg.
Case Study 2
Now suppose we have the same 500 liters RMG and want to determine its mixing capacity for product ‘B’ having a bulk density of 0.8 g/ml.
We will use the same formula and after putting values the result will be
500 × 0.8 = 400 kilograms
At 75% the working capacity will be
400× 75/100 = 300 kg.
Conclusion
The working capacity of RMG for product A having a bulk density of 0.6g/ml will be 225 kilograms and for product B having a bulk density of 0.8 g/ml will be 300 kilograms.
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