Planetary mixer - Pharmaceutical Engineering B. Pharm Third Semester PDF Notes

Planetary mixer

Principle

• Mechanism of mixing is shear

• Shear is applied between moving blade and stationary wall

• Mixing arm moves around its own axis and around the central axis so that it reaches every spot of the vessel

• The plates in the blades are sloped so that powder makes an upward movement to achieve tumbling action also

Construction

• Consists of vertical cylinder shell which can be removed

• The blade is mounted from the top of the bowl

• Mixing shaft is driven by planetary gear and it is normally built with variable speed drive

Uses

• Break down agglomerates rapidly

• Low speeds are used for dry blending and fast for wet granulation

Advantages

• Speed of rotation can be varied at will

• More useful for wet granulation process

Disadvantages

• Mechanical heat is buildup within the powder mix

• It requires high power

• It has limited size and is useful for batch work only