A dynamic model of coal products discharge in a jig

The paper presents a simple dynamic model of coal product discharge in a jig. The model is based on the principle of mass conservation of coal density layers transported in the jig's bed. It can be used to investigate dynamic properties of a discharge zone in a jig and to design control systems of products discharge in a jig. The model has been developed with the use of Matlab/Simulink software. The transfer function of the discharge system in a jig can be approximated by a nonlinear integrating element with saturation determined by the height of the coal layer placed above the upper product overflow gate. Dynamic parameters of the system depend on the dimensions of the jig compartment, parameters of the bottom product discharge gate and tonnage of the yield of density fractions in the feed. The model can be used to design and optimise control systems of refuse discharge in jigs. The simulation model generates the separation density signal similar to the signal produced in the jig and measured by the density meter. The root mean squared error between the measured and simulated changes is ca. s = 0.027 g/cm3.