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Criteria
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Type
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Description
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Advantage
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Disadvantage
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Feeding type
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Hold-on (or head feed)
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Only the panicle is fed into the machine
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Straw remains intact
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Lower throughput
Complex machine
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Feed-in
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The hole crop is fed into the machine
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Higher throughput
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Clogging with very wet or long straw. Higher power requirement
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Crop flow
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Axial-flow
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Whole crop moves axially around the drum periphery
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Low weight
Does not need straw separators
Good performance with wet crop
Can be used for Basmati rice
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Higher power requirement
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Conventional
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Crop flows tangentially through gap between drum and concave
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Lower power requirement
Concave clearance easy to set
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Needs straw walker for separating grains from straw
Problems in wet crop
Causes high breakage in Basmati rice
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Threshing elements
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Pegteeth
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Rows of peg teeth attached to threshing drum
Typical axial flow thresher drum
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Grinds up the straw
Performs well with wet straw
Simple design
Cheap
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|
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Rasp bar
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Rasp bars attached to threshing drum, usually used in tangential flow threshers
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Lower power requirement
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Problems with wet straw.
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Wire loop
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Typically used in hold-on threshers and head feed combines
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Lowest power requirement
Thin wire loops comb grain and thresh through impact
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Wears quicker
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