Experimental Study of the Process of Preliminary Separation of Light Impurities from Combed Heap

Introduction. There are specified and considered the trends determining the directions for the development of grain harvesting equipment. One of the most important issues is increasing the productivity of a grain harvester while maintaining its acceptable metal content and energy consumption. Traditional solutions have largely exhausted themselves, so a promising solution is the use of the technology for combing of standing plants. Aim of the Study. The study is aimed at determining the proportion of light impurities separated from the grain heap depending on the height of the combing header outlet. Materials and Methods. There was used an experimental method to examine a combing header with preliminary separation of light impurities. During the experiment, the height of the stripper header outlet was varied. The mass of the separated chaff and its composition were determined. When processing the experimental data, there were obtained relationships meeting the study objectives. The results are divided into two groups: the results with the use of solid shields installed on the combing header rear wall and those without solid shields, when the rear wall is a mesh surface. Results. There has been developed a method for determining the proportion of separated light impurities. There have been found the dependences of the proportion of separated light impurities and the proportion of lost grain on the combing header outlet height. There has been identified an optimal range of the combing header outlet height if the solid shields removed from the combing header rear wall. If the range of combing header outlet height is from 124 to 130 mm, the proportion of separated light impurities reaches 13%, while grain losses remain relatively low. Discussion and Conclusion. In the context of separating the heap light impurities, there has been obtained a significant result, which allows not only unloading significantly the grain harvester cleaning system and increasing its productivity, but also improving the efficiency of separating grain on the pre-drum separating device or directly on the grate bottom of the inclined chamber.