Effectiveness of Three Types of Grain Separator for Crop Matter harvested with a Stripping Header
M. A. Neale, R. N. Hobson, J. S. Price and D. M. Bruce
Biosystems Engineering Volume 84, Issue 2 , February 2003, Pages 177-191
2003
บทคัดย่อ
The performance of three types of separator (axial flow, straw walker and multi-cylinder), designed to separate grain from material other than grain (MOG), were tested in the laboratory and field. The straw walkers were mounted in a conventional combine harvester and the multi-cylinder separator in an experimental trailed stripper harvester, and evaluated during in-field harvesting trials. An axial flow separator was built especially for laboratory evaluation. The crops used for the tests had all been harvested with stripper headers and passed through conventional threshing drums. The grain and MOG that passed through each stage of each separator under test was collected by trays along the machine so as to reveal how the individual stages of the separators performed, and hence inform developments in separator design. Although the data were gathered from independent evaluations of the three separators, useful comparisons were possible.
MOG input to each separator close to 4 t h-1nd grain input of 1 – 2.7 t h-1 gave separation efficiencies of 95% with 3.1 to 4.2 m2of straw walker area, 1.7 m2 of multi-cylinder grating and 1.0 m2 of grating in the axial flow rotary separator.
The axial flow separator allowed 29% of barley MOG through with the grain whilst the straw walker allowed 13%. In wheat, the straw walker allowed 37% MOG through, compared with 56% by the multi-cylinder separator. The MOG fraction entering a separator after stripping is predominantly leaf and light straws. This does not form the open structure seen when long straw is present but tends to ‘mat’, making grain separation more difficult. Rotary separators, both axial and tangential, appear better suited to handling this stripped material than do straw walkers because their more aggressive action teases out the material and allows easier release of the grain, but it also breaks up MOG resulting in worse MOG retention.