In a thresher, the cylinder separation efficiency can be improved by increasing
GATE AG - 2023,
Answer: B
Separation at the cylinder improves by increasing cylinder speed.
A faster cylinder strikes the crop harder and throws it against the concave with greater centrifugal force, so more of the detached grain passes through the concave openings. Threshing and separation through the concave both rise with peripheral speed, which is why speed is the main adjustment for hard-to-thresh crops (at the risk of more grain damage).
Increasing the cylinder-concave clearance makes the crop mat looser against the concave, so less grain is rubbed and pushed through. Increasing the feed rate thickens the mat, so grain is trapped in the straw and carried out. The key treats speed, not a larger diameter, as the variable that improves separation efficiency.
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