New method to detect grain in grain-MOG-mixtures

摘要

To use the application potential of simulation models for the development of combine cleaning systems to full capacity, the established models have to be validated. The validation of physical properties of grain and straw, for example, is carried out using simplified test rigs [1],[2]. For the validation of simulations of the grain segregation and sieving, the penetration time is used. Another possibility to verify the segregation function on a more detailed level, is based on examining the particle movement. In previous studies the movement process on a preparation pan for grain and MOG (Material Other than Grain) was analysed by using a high-speed camera and corresponding colour recognition algorithms [3]. However, a high error rate complicates the automated analysis to distinguish between grain and MOG. Furthermore, due to the absentee of visual accessibility, the recording of the high-speed images can only be carried out in the surface layer. Here additional friction between particles and sidewall takes effect on the components, which is why their movement differs from the average particle movement. For this reason a new method to detect grain in grain-MOG-mixtures based on X-ray imaging is used for analysing the grain segregation process. A miniature test rig generates a segregation process which can determined with an X-ray source and an X-ray detector system. With this experimental setup the three-dimensional movement behaviour of the grain in the grain-MOG-mixture can be proved visually. Furthermore the grain layer height and the distance from the sieve to the grain layer over time is calculated to assess and compare different segregation processes with different excitation parameters and throughputs. Using X-rays makes it possible to determine the grain-MOG-mixture in all three dimensions and thus reducing the influence of wall friction effects.