Substantiation of technological parameters of wet maize ear threshing
Department of Agricultural Machinery Lithuanian University of Agriculture,Studentu Str.15A, LT 53362 Akademija, Kaunas r., Lithuania;e-mail: Sigitas.Petkevicius@lzuu.lt
The paper presents the test results of wet maize ear threshing process during the period of 2003–2005. Grain biometrical indices, technological parameters of threshing apparatus, and the feed rate of the maize ears appeared to be the most significant causes of threshing drum losses, grain damage, and the threshed amount of grains thrown to the straw walkers. The concave clearance of the threshing apparatus is related with and depends on the internal diameter of the maize ears and cores. The concave clearance at the beginning should be approximately 10 mm smaller that the average ear diameter, and at the end it should be equal to core diameter. The clearance between the rasp bars and the transverse bar at the concave end should be controlled by the computer because the ears of different diameters are fed into the threshing apparatus. When wet ears (grain moisture content >35%) are threshed the drum losses are reduced by varying the speed of the drum rasp bars and the clearance between the drum and the concave. Rational rotational speed of the drum rasp bars is 17 m s -1. When wet ears are threshed the even ear flow rate should be supplied into the threshing apparatus. The medium load of one meter rasp bar length should be 0.82 kg (s m)-1.