Automatic control system of jet grinding based on experimental data
The relevance of the paper subject is determined by the need to reduce the fine grinding energy consumption by process control proposed to be carried out on the basis of the results of acoustic monitoring.
The problem of choosing the optimal grinding mode and control methods have been considered for a long time. The work of many Soviet and foreign authors is devoted to questions of improving the grinding units efficiency, in particular, they used the control of gas-jet grinding based on the analysis of flow-pressure characteristics of the pneumatic transport network, pressure in the grinding chamber. However, in these cases, the delay time was too long and the maximum load could not be maintained.
The aim of this work is to justify the structural scheme of the automatic control system of a jet mill based on experimental studies of the control object and the results of acoustic monitoring of the grinding zone
The efficiency of the jet grinding plant depends on the loading degree of the grinding chamber and the closed grinding system as a whole. To increase mill productivity, it is necessary to maintain an optimal fill level of the grinding chamber. The dependence of productivity on the filling degree is extreme, and it is necessary to take into account the uneven loading due to the operation of the material circulation system. It is proposed to realize this on the basis of the acoustic signal analysis of the grinding zone.
The paper proposes an automatic control system on maximum performance criterion, taking into account the process features. It is described the functional and created a structural diagram of a grinding plant for a closed grinding cycle. To describe the material supply process, a hopper model is used taking into account changes in its outlet area. The operation process in the grinding zone is considered as a change of material concentration in the chamber. For material flow modeling in the classifier, circulation load pulsations in a closed grinding cycle are taken into account. The developed scheme of the automatic control system includes two control levels and a control object description. The results allow qualitatively improving the control of the grinding process.
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