In an air screen grain cleaner, the scalper screen is the uppermost screen whose function is to:
Options:
(A) Remove large coarse impurities like straw, stones, and pods while allowing sound grain to fall through
(B) Separate fine sand, dust, and broken grain from whole kernels
(C) Separate grains on the basis of specific gravity differences
(D) Aspirate light chaff and dust using an upward air stream
Answer Key:
A
Step-by-Step Solution & Explanation
The scalper (top) screen has perforations larger than sound grain kernels. Large impurities are retained on top and discharged as oversize, while desired grain and smaller contaminants drop through to the grading screens.