Size Reduction - Pharmaceutical Engineering B. Pharm Third Semester PDF Notes
Size Reduction
Contents of this session
• Introduction to size reduction
• Applications of size reduction
• Factors affecting size reduction
• Mechanism of size reduction
• Laws governing size reduction
• Classification of mills
• Ball mill
• Fluid Energy mill
• Hammer mill
• Edge runner mill
• End runner mill
Learning objectives
At the end of this lecture student will be able to:
• Explain various applications of size reduction
• Discuss the factors affecting size reduction
• Discuss various mechanisms of size reduction
• Explain the laws governing size reduction
• Discuss on the construction and working of a ball mill
• Discuss the process of Fluid energy mill and Hammer mill operation
• Explain the construction and working of Edge runner and End runner mill
Summary
• Size reduction is the process of reducing the particle size of a substance to a finer state
• The factors that affect size reduction process are hardness, toughness, stickiness, moisture content, ratio of feed to product ratio etc.
• Moh’s scale is used to quantify the hardness of a substance
• The applications of size reduction include efficient mixing of different ingredients, increased drying and improved absorption
• Different mechanisms of size reduction includes cutting, compression, impact and attrition
• Laws governing size reduction include Kick’s Law, Rittinger’s Law, and Bond’s Law
• Ball mill mechanism of operation include both impact and attrition
• Optimum speed of ball mill operation at which maximum efficiency of size reduction obtained is termed as Critical speed
• Fluid energy mill utilizes both impact and attrition mechanism of size reduction
• The feed to the Fluid energy mill should be pre size reduced
• It is used for size reduction of thermolabile substances like antibiotics, vitamins etc..
• Hammer mill utilizes impact as the mechanism of size reduction process
• Optimum speed of ball mill operation at which maximum efficiency of size reduction obtained is termed as Critical speed
0 Comments: