Crop loss monitoring

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  • 1. M&E/GHA/Combines/04/05 1 Combine Harvesters Grain Loss

2. M&E/GHA/Combines/04/05 2 Combine Harvesters Grain Loss Zero grain loss is unachievable due to a culmination of circumstances. The best any operator can hope to achieve is an acceptable level that is consistent with the crop being harvested . Loss will occur four main areas. from the ear prior to the combine entering the crop. Field Loss from the straw walkers. Walker Loss from the header. Header Loss from the sieves. Sieve Loss 3. M&E/GHA/Combines/04/05 3 Combine Harvesters Grain Loss monitors Cab Monitor Straw Walker Sensor Sieve Sensor 4. M&E/GHA/Combines/04/05 4 Combine Harvesters Grain Loss monitors Grain loss in most combines is monitored by the use of sounding boards. The boards cover the full width of the straw walkers and sieves. The grain hits the sensor and this either generates an electric impulse or a sound wave that is picked up by a microphone The signals are then transmitted to the monitor in the cab usually appearing as a light signal, bar graph . With some harvested crops the monitors are not effective due to the straw creating more impulses than the seed. 5. M&E/GHA/Combines/04/05 5 Throughput % Loss A Grain Loss increases in proportion to throughput. Point A = separation Capacity at concave overload Combine Harvesters Grain Loss 6. M&E/GHA/Combines/04/05 6 Combine Harvesters Grain Loss A B C D A = Field Loss B= Header Loss C = Thresher Loss B = Total Loss 7. M&E/GHA/Combines/04/05 7 Header Width Yield Kg/ha 2.6m 3.0m 3.3 3.6 3.9 4.5 5.1 5.8 6.7 4,000 228 268 295 322 349 402 456 510 590 4.500 257 302 352 362 392 463 513 573 610 5.000 285 355 369 402 436 503 570 637 738 5.500 314 369 402 443 479 553 627 701 811 6.000 342 402 443 483 523 604 684 764 885 Combine Harvesters Grain Loss 8. Combine Harvesters Grain Loss M&E/GHA/Combines/04/05 8 Loss of grain over the sieves. Cylinder speed too high concave clearance too close causing over threshing Adjust speed and clearance. Ground speed too high. Incorrect sieve settings Fan speed to slow/high. Air diffusers incorrectly set. Shaker speed incorrect Excessive returns. Uneven feed. Reduce ground speed Adjust sieves to a wider setting Adjust fan speed Adjust diffusers. Check belts and speed. Adjust sieves 9. Combine Harvesters Grain Loss M&E/GHA/Combines/04/05 9 Straw Walker Loss. Over threshing at the cylinder. Concave blocked with dirt and mud. Heavy straw. Straw walker speed too slow. Filler bars still fitted. Straw walker curtains damaged. Ground speed too fast. Insufficient feed (thin crop) Concave too wide. Excessive returns to cylinder. Reduce cylinder speed. Clean out concave Reduce forward speed. Check belt adjustment and speed. Remove filler bars. Check curtains and replace if necessary. Reduce ground speed. Increase ground speed. Adjust concave. Adjust sieves 10. M&E/GHA/Combines/04/05 10 Combine Harvesters Yield Monitoring Signal Grain Flow 11. M&E/GHA/Combines/04/05 11 Combine Harvesters Grain Damage Grain sample shows excess of cracked grain. Cylinder speed too high. Reduce cylinder speed. Concave clearances too close Adjust concave. Grain cracked in returns system. Check returns, if good grain is in the system open top or bottom sieves. Slack chains on good grain and/or returns elevator. Adjust elevator chains. Filler bars fitted. Remove filler bars. Sieve settings. Adjust sieves to a wider setting 12. Combine Harvesters M&E/GHA/Combines/04/05 12