Question

Which among the following equipment utilizes surface texture of the material in separation process
(A) Inclined draper
(B) Velvet roll separator
(C) Spiral separator
(D) Magnetic separator
Choose the correct answer from the options given below:

• A. (A) and (B) only.
• B. (A), (B) and (C) only.
• C. (A), (B) and (D) only.
• D. (B) and (D) only.

Hint:

Remember that both the inclined draper and the velvet roll separator are classic examples of frictional/textural separators where rough seeds cling to a moving surface (fabric or belt) while smooth seeds slide off under gravity.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Seed separation equipment is designed to separate different types of seeds based on physical properties such as size, shape, density, color, surface texture, or magnetic properties.

Step 2: Detailed Explanation:
Let us analyze how each machine operates:

(A) Inclined draper: This device uses an inclined, moving canvas or rubber belt (draper).
A seed mixture is fed onto the inclined belt. Smooth seeds, having a lower coefficient of friction, slide or roll down the incline and are collected at the bottom.
Rough-textured seeds cling to the textured belt surface and are carried upward, falling off at the top.
This is a direct separation based onsurface texture and shape. Thus, (A) is included.

(B) Velvet roll separator (Dodder mill): This machine consists of two inclined rolls covered with velvet fabric, rotating in opposite directions.
Smooth crop seeds roll down the valley between the rolls and are discharged at the end.
Rough-textured weed seeds (such as dodder) cling to the velvet fibers and are carried over the top, separating them from the smooth seeds.
This is also a direct separation based onsurface texture. Thus, (B) is included.

(C) Spiral separator: This is a stationary gravity-based device that separates seeds based on their shape and rollability, not surface texture. Round seeds roll faster down the spiral, gaining speed and moving to the outer edge, while flat or irregular seeds slide slowly and remain near the inner column.

(D) Magnetic separator: This machine separates seeds based on magnetic properties. It relies on mixing the seed batch with a magnetic powder (such as iron powder) and water. While rough seeds can bind the powder better, the primary separation force is magnetic, not mechanical surface friction.
Therefore, the inclined draper and the velvet roll separator are the primary devices that utilize surface texture.

Step 3: Final Answer:
The correct option is (A), representing (A) and (B) only.