End Runner Mill / Mechanical Mortar and Pestle - Pharmaceutical Engineering B. Pharm Third Semester PDF Notes

End Runner Mill / Mechanical Mortar and Pestle

Principle

Size reduction is done by crushing or compression due to heavy weight of steel pestle. Shearing stress is also involved during the movement of mortar and pestle

Construction

•   A steel mortar is fixed to a flanged plate

•   Underneath the flanged plate, a beveled cog fitting is attached to a horizontal shaft with a pulley

•   Dumb bell shaped pestle is flat rather than round

•   The pestle carries a hinged arm for emptying and cleaning

Working

The material to be ground is placed in the mortar

The scraper puts the material in the path of the pestle

The mortar revolves at high speed

The pestle is placed in the mortar

The rotating mortar causes the pestle to revolve

Thus size reduction is achieved by shearing as well as crushing

The material is collected and passed through a sieve to get the powder of desired size

Uses

Suitable for fine grinding

Disadvantage

Not suitable for unbroken drugs