Question

Destoner is a form of separator that separates the:

(A) Feed material into two fractions as per the difference in shape factor

(B) Feed material into heavy particles from the lighter particles

(C) Feed material into two fractions only as per the difference in specific gravity

(D) Feed material into multiple fractions as per the difference in specific gravity

Choose the correct answer from the options given below:

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

Hint:

Recall what property difference a destoner actually uses, and how many output streams it produces.

Answer 1

The Correct Option is B

A simple way to solve this is to sort grain cleaning machines by the property they use to separate material.

Screen or sieve separators use size difference. Disc separators and indent cylinder separators use length or shape difference. Destoners and gravity separators use specific gravity (density) difference, aided by air and vibration to stratify heavy and light particles.

Once you place the destoner in the specific gravity group, check the four statements against that single idea. (A) talks about shape factor, that belongs to a different machine, so it is out. (D) talks about multiple fractions, but a destoner is built to give only two output streams (light grain out one chute, heavy stone out another), so it is out too.

That leaves (B) and (C). Both are just two ways of stating the same working principle, heavy particles are separated from light ones, and this happens by specific gravity difference into exactly two fractions. Since both statements are true descriptions of the same machine, they belong together.

\[\boxed{\text{(B) and (C) only}}\]