5.1 Model based on empirical data

In order to analyze and utilize the extensive experimental data effectively a software was developed. This software helps in systematization of the results and in calculation of characteristic diagrams. Both – data and diagrams – are put in a data bank from were they can be recalled selectively. So it is possible to predict the results of a jigging process with similar parameters of the materials and the process. In figure 4 a screen shot of the software is shown. In the right part the user can chose several parameters while in the left part the results of the calculations are shown.

Figure 4: View of the user surface of the empirical model

In the model the measured dependences between the effectiveness of separation given as foreign content and the duration of the treatment is described with an e-function for every run. Predictions about the effectiveness are possible if the new process parameter is within the range of the measured parameters. Then an interpolation between the already measured parameters leads to the wanted result. Extrapolations are not allowed, because the software only reflects the measured data without consideration of “inner” physical associations.

The experimental works up to now and the deduced empirical functions show that such a model comes very soon to its limits, as alternatives to this physical models become more and more established in processing. One possibility of developing such models is the use of the so called “Discreet Element Method”. The idea of this method is that all particles N of a granular system are considered as individuals. For each individual Newton’s equation is solved for each degree of freedom. Subject of future works shall be to applicate the DEM on the jigging process. With this step the difficulties in the design of the machine and the adaption to new materials should be reduced.