On The Autonomy Of Local Systems In Mine Ventilation Control - A Theoretical Approach Based On The Introduction Of Auxiliary Systems - Introduction

At its lowest hierarchical level, the mine ventilation control system consists of local systems controlling the concentration of noxious gases in the air currents of various branches of the ventilation network, and of local systems controlling the air flow rates through those branches in which it is not necessary to regulate the concentration of any noxious gases. With respect to the noxious gas concentrations, the manipulated variables are air flow rates, while with respect to the air flow rates - the manipulated variables are aerodynamic resistances of the corresponding branches. Since there is an interdependence between the air flow rates in the ventilation network branches controlled through changes in aerodynamic resistance, the total system of mine ventilation control falls in the class of multivariable systems. The treatment of individual branches of a controlled ventilation network as separate plants presupposes an absolute autonomy of local systems, which is an untenable concept. The present paper is an attempt to break up the multivariable control system of the noxious gas concentrations and the air flow rates into autonomous (mutually unrelated) local control systems. The plant discussed is a ventilation network of arbitrary configuration with a single main axial fan. Because of the complexity of the problems involved, the multivariable control system of noxious gas concentrations and air flow rates has been described as linear, with constant and lumped parameters.