Substantiation of the rational technological parameters for threshing high-moisture corn ears

Abstract

The article presents the results obtained during the research of harvesting mid-moisture corn ears Auxxel and high-moisture corn ears Lapriora (moisture level higher than 30%) using combine-harvester with axial threshing and separating rotor A, and with tangential threshing cylinder B. The rational technological parameters of threshing were justified by experimental research. It has been established, that when corn ears were fed to the threshing device A at the maximum feedrate of 24.8 kg s-1, total grain losses were 1.56 times lower compared to the grain losses of the combineharvester B. The lowest grain damage rate was observed when corn ear feedrate was approximately 20 kg s-1. Upon increasing or decreasing the feedrate, corn damage rate increased. When threshing high-moisture corn ears, grain damage rate for the harvester A was higher by 0.67 percentage units compared to the harvester B. The maximum allowed peripheral velocity for the tangential threshing cylinder was 15 m s-1, while for axial rotor – 18 m s-1. Grain loss should be reduced not by increasing cylinder peripheral velocity but rather by altering the clearance between the cylinder (or rotor) rasp bars and the concave. In a tangential threshing device B, the clearance at the third concave bar must be in the interval 20–27 mm, which is approximately 22 mm smaller than average corn ear diameter. Combine-harvester operates efficiently when fuel consumption for threshing one tone of grains is least, and grain loss does not exceed the permissible level. Using combine-harvester A and applying the rational feedrate of 20 kg s-1, hourly fuel consumption reached 90.5 litres, and threshing of one tone of grains required 1.31 litres of fuel.