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Renin Angiotensin Mechanism.

End Runner Mill.

 End Runner Mill.

Principle:

  •  It works on the principle of Crushing and Attrition. 

Diagram:

Construction:

  • It consists of a weighted pestle mounted eccentrically in a ceramic, granite or metal mortar, which is rotated by a motor. 

  • The pestle rotates by friction and is free to rise and fall in the mortar so that its grinding action involves both impact and shear, the material being crushed and rubbed between it and the rotating mortar.

  • Spring-loaded scrapers ensure that material is constantly returned to the grinding area and at the end of the operation the pestle can be swung clear of the mortar to facilitate emptying and cleaning.

Working: 

  • Pastel is moved up and the material to be introduced is introduced into the mortar.

  • The pastel is lowered and the electric supply of the mill is started.

  • The material is crushed under the weight of pastel, the rotation of the pastel causes size reduction by attrition as particles are crushed and moved under shear force between pastel and bed wall.

  • The scrapper helps keep the material in the path of the pastel.

  • Once size reduction is done the pastel is moved upwards, the product is collected and the mill is washed, dried and kept ready for the next operation.

Advantages:

  • Produces moderately fine powder.

  • Useful for fibrous products like leaves and roots.

  • Wet grinding with very viscous material such as ointments and paste is also possible.

Disadvantages:

  • Not useful for sticky products.

  • Potency can be compromised.

  • Open operation.

  • Wear and Tear.

Commonly Asked Questions.

  1. What is size reduction? Write Principle, Construction and working of the End Runner Mill.
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