Subtopic: Drying and milling of cereals, pulses and oilseeds
Question Statement:
In modern rice milling, a rubber roll sheller operates with two rubber-coated rollers rotating in opposite directions. The peripheral speed ratio of the fast roller to the slow roller is typically kept around:
Options:
(A) $1.0 : 1.0$ (equal speeds)
(B) $1.2 : 1.0$ to $1.25 : 1.0$
(C) $2.5 : 1.0$
(D) $4.0 : 1.0$
Answer Key:
B
Step-by-Step Solution & Explanation
Rubber roll shellers maintain a peripheral speed differential ratio of roughly $1.2 : 1$ (e.g. fast roll at $12 - 14\text{ m/s}$ and slow roll at $10 - 11\text{ m/s}$) to apply optimal shearing force that strips the husk without cracking the kernel.