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ABE 223: ABE Principles – Machine Systems

Grain Harvesting

Tony Grift

Dept. of Agricultural & Biological EngineeringUniversity of Illinois

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Video: Modern Marvels Harvesting 4:33 – 12:40

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Self propelled combine, JD9750 w/ grain head

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Functional Processes in a combine harvester

Gather Cut Convey Thresh Separate

Unload Store Convey

Clean

straw

chaff

chaff

Header FeederHouse

Threshing cylinder

UnloadingAuger

Separator

CleaningShoe

Grain Tank Clean GrainAuger

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Combine Power Requirements

• Straw Walker Type• CAT Lexion - 250-290 HP• Deere

• Walker Type - 190-308 HP• CTS - 275 HP• STS - 290-325 HP

• Rotor Type• Case Axial Flow - 174-280 HP• New Holland Twin Rotor - 240-280 HP

• Power Boost - On-the-go Unloading -30 HP

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Cutaway view of self-propelled combine

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Functional Processes

Gather Cut Convey Thresh Separate

Unload Store Convey

Clean

straw

chaff

chaff

Header FeederHouse

ThreshingCylinder

UnloadingAuger

Separator

CleaningShoe

Grain Tank Clean GrainAuger

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Gathering and cutting

• Cutterbar (Cb)• Reel (Rl)

• Plain bat reel• Pickup reel with cam controlled teeth

Floating cutter bar construction

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Finger sensors for cutter bar height control

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Pickup Header for windrowed crops

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Self propelled combine, JD 9650 w/ 8 Row Corn Head

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A corn head row unit draws in the stalks after which snapping rolls and stripping plates pulls off the ears

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Functional Processes

Gather Cut Convey Thresh Separate

Unload Store Convey

Clean

straw

chaff

chaff

Header FeederHouse

Threshing cylinder

UnloadingAuger

Separator

CleaningShoe

Grain Tank Clean GrainAuger

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The feeder house removes pods (soybeans) or ears (corn) from the header and transports them into the machine

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Threshing is accomplished by rubbing pods or ears against themselves and the metal grates surrounding the concave

Gather Cut Convey Thresh Separate

Unload Store Convey

Clean

straw

chaff

chaff

Header FeederHouse

Threshing cylinder

UnloadingAuger

Separator

CleaningShoe

Grain Tank Clean GrainAuger

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Combine Layouts

• Conventional • Threshing

• Rasp bar cylinder/ Spiked tooth cylinder• Separation

• Straw walker • Cleaning shoe with fan blower

• Conventional with rotor separation• Rotors, threshing and separation in single rotor

• Cleaning• Dyna Flow (JD)• Quadra Flow (JD)

• Specials• Case/Claas Accelerated Pre-separation system

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Threshing cylinder (drum)

• Cylinder- concave combination

• Rasp bar• Threshing

between rasp bar and concave

• Grain fall through concave on grain pan (Gp)

• Spiked tooth• Threshing

between teeth on cylinder and concave

• Beater (Bt) removes straw from cylinder

• Retarder flap (Rf) catches thrown grain from beater

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Corn ears in raspbar threshing cylinder

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JD Combine with a spike-tooth cylinder and dual rotary separation section

Spike tooth cylinder

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JD Conventional layout

Feeder house / conveyor

Transverse cylinder

Beater

BlowerStraw walkers

Unloading AugerConcave

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Conventional radial cylinder with beater and straw walker separation

Grain

Straw

• Beater speed tied to cylinder speed

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Straw Walker

• Straw Walkers• Several long channels

mounted on a crankshaft

• Channels follow circular or elliptical pattern

• Straw moves toward rear of combine

• Grain and chaff separated from straw due to oscillatory action of walkers

• Gravity and friction cause separation

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Claas Lexion 450

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CAT (Claas) Lexion APS (Acceleration and Pre-Separation system)

• Pre-separation cylinder

• Removes easily threshed grain

• More even flow to main cylinder

• Higher material throughput

Claas Forage Harvester (SPFH)

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CAT (Claas) Lexion APS (Acceleration and Pre-Separation system)

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Separation

• Takes out another 20% of grain• Straw walkers (Sw)

• Linear vibration effect• Air blown under the straw• Grain separated under gravitational forces

• Rotary separation• Based on centrifugal effect on heavier grain particles• JD Combs material over grates

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Fig 10.7 New Holland combine with dual threshing / separating rotors.

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JD CTS (Cylinder Tine Separation) system (1991)

• Rasp bar threshing cylinder

• Beater• Twin Tine-rotary

separation

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JD 9750 STS

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JD STS Combine (Single-Tine Separation)

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JD STS Rotor (Single-Tine Separation) system

• Combination of threshing and separation in one cylinder

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JD STS Drive system

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CASE Axial Flow Rotor System

Grain

Straw

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Cleaning

• Fan blows fine chaf away from grain kernels• Adjustments

• Fan speed• Chaffer opening• Sieve openings

• Overcleaning: • Fan speed too high• grain blows out back• Clean grain in tailings

• Undercleaning• Fan speed too low• Chaffer and sieve openings too far open• Heavy tailings

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Dyna-Flo Cleaning System

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Quadra-flow cleaning system

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Functional Processes

Gather Cut Convey Thresh Separate

Unload Store Convey

Clean

straw

chaff

chaff

Header FeederHouse

Threshing cylinder

UnloadingAuger

Separator

CleaningShoe

Grain Tank Clean GrainAuger

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Grain Tank Capacity

• Case - 145-210 bushels• Deere - 182-240 bushels• New Holland - 190-240 bushels

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Unloading rate

• Deere - 2.2 bushels/second• Case - 1.9 bushels/second• CAT - 2.5 bushels/second

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Harvest losses

• Preharvest losses• Wind shatter losses• Lodged grain• Field too wet for harvest

• Header losses (Grain lost due to rough handling by the cutter bar)

• Machine losses• Threshing loss(Unthreshed grain that leaves out of the

rear)• Separating loss (Threshed grain that leaves out of the rear)• Cleaning loss (reduced crop value due to MOG in grain

tank)

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Combine losses can be substantial.

Table 10.1 Typical Combine Losses in Midwestern U.S. (percent of gross yield).

  Shatter and Cutter bar losses

Cylinder loss

Separating & cleaning loss

Total loss

Oats 1.5 0.8 2.0 4.3

Wheat 3.4 0.1 0.6 4.1

Soybeans 5.8 0.6 0.7 7.1

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How to determine losses and make adjustments to reduce them

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Cutter bar loss

• Symptom• Lodged and wind shattered grain out of reach of cutter bar

• Remedy• Minimize by keeping head close to the ground• Automatic head adjustment in height and tilt for cross

slopes• Timely harvest, before crops start shattering• Special row crop head for soybeans clamps crop stalks

rigidly while being cut

Hill slope combine

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How to determine losses and make adjustments to reduce them

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Reel losses

• Symptom• Kernels counted after header passes before straw output

• Remedy• Adjust the speed of the reel• Adjust the reel height• Keep reel speed about 1.25-1.5 times travel speed• Variable speed drive is best

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Threshing losses: Concave cylinder adjustments

Concave clearance

Cylinder speed

Results or indicators

wide - Underthreshed condition, straw walker area indicates this.

wide slow Material builds up over the concave. Pinch/ pull operation is impaired; reduced separation

wide fast Ricochet effect, grain damage, cracked kernels in the grain bin

tight - Overthreshed condition, broken straw over straw walkers and on cleaning shoe

tight slow Heavy tailings, broken straw in bin and straw walkers

tight fast Damaged grain, broken straw in bin; worst misalignment of all

correct correct Cylinder speed is 800-1000 rpm. Heads still attached but grain thoroughly threshed; clean grain in tank; 1 tbsp of

trash/paddle in tailings elevator

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Separation (straw walker) losses

• Poor separation due to• Underthreshed situation, Low fan speed

• Straw walkers covered with blanket of unthreshed material. Concave clearance too large

• Overthreshed situation• Grain walks out of the back of the machine because walkers

are plugged with ground up straw. Concave clearance is too tight.

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Residue Management

• Residue-Material other than Grain (MOG) that remains in the field

• Baling Straw• Ground cover for

no-till/reduced till• Reduce erosion

• Straw Chopper• Chaff Spreader

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Claas Lexion with Laser Pilot guidance

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Moisture sensor for precision ag

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Harvesting systems: how do you orchestrate multiple machines working together?

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ABE 223: ABE Principles – Machine Systems

Grain Harvesting

The End

Dept. of Agricultural & Biological EngineeringUniversity of Illinois