Subtopic: Fluidization of granular solids – pneumatic, bucket, screw and belt conveying
Question Statement:
In a vertical bucket elevator, clean centrifugal discharge of grain occurs when the pole distance $h = \frac{g}{\omega^2}$ is:
Options:
(A) Less than the head pulley radius ($h < R$)
(B) Equal to the elevator vertical lift height
(C) Greater than twice the head pulley radius ($h > 2 R$)
(D) Strictly zero
Answer Key:
A
Step-by-Step Solution & Explanation
Centrifugal discharge occurs when the centrifugal force exceeds the gravitational force at the outer bucket edge, which corresponds to the pole distance $h = g/\omega^2$ being less than the head wheel radius $R$ ($h < R$).