Question

Which sieving equipment is most commonly used in flour milling to separate bran from endosperm?

• A. Vibrating screen
• B. Plansifter (gyrating sifter)
• C. Trommel screen
• D. Grizzly screen

Hint:

Plansifters are key to wheat milling systems because they handle multiple classifications in a single vertical stack, optimizing space and energy.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
This question asks for the specialized industrial sieving equipment used in the flour milling industry to classify ground wheat fractions.

Step 2: Key Formula or Approach:
In flour milling, the separation of bran from endosperm requires precise, high-capacity classification.
The separation process must handle large quantities without blinding (clogging) the sieves or breaking down delicate components excessively.

Step 3: Detailed Explanation:

• Plansifter (gyrating sifter): Consists of a series of horizontal sieves stacked vertically, executing a planar gyratory (circular) motion. It is the industry standard for flour milling because it provides gentle, high-capacity, multi-stream separation that stratifies materials according to size and shape.

• Vibrating screen: Uses vigorous vertical vibrations which are too harsh for fine flour milling, potentially damaging the screen cloth and causing fine particulate dust issues.

• Trommel screen: A rotating cylindrical screen used for coarse raw cleaning (e.g., sorting large seeds, stones, and dirt) and is unsuitable for fine milling separations.

• Grizzly screen: A robust parallel-bar device used in mining and raw mineral handling for sizing extremely coarse rocks.

Step 4: Final Answer:
Therefore, the plansifter is the correct equipment.