Subtopic: Functional requirements, principles of working, construction and operation of manual, animal, tractor and renewable energy operated equipment for tillage, sowing, planting, fertilizer application, inter-cultivation, spraying, mowing, chaff cutting, harvesting and threshing
Question Statement:
Which of the following factors will INCREASE the proportion of grain separated through the threshing concave grate (concave separation efficiency) in a tangential combine thresher?
Options:
(A) Increasing cylinder peripheral speed within recommended agronomic limits
(B) Decreasing the clearance between the threshing cylinder and the concave
(C) Operating at excessively high crop feed rates exceeding the rated MOG (Material Other than Grain) capacity
(D) Decreasing crop moisture content of grain and straw
Answer Key:
A, B, D
Step-by-Step Solution & Explanation
- **Statement A is correct:** Higher peripheral speed increases impact energy and centrifugal acceleration of grain through the open concave grates.
- **Statement B is correct:** Reducing concave clearance increases mechanical rubbing intensity and accelerates grain detachment and grate passage.
- **Statement C is incorrect:** High crop feed rate creates a dense straw mat cushion across the concave that traps detached grains, reducing concave separation and overloading straw walkers.
- **Statement D is correct:** Drier crop material shatters easily and flows freely through the grates without clogging.