Application Of Variable Frequency Speed Regulation Based On PLC Control In The Pressure Fire Prevention System

The gob of Sitai Coal Mine has a complex connectivity relationship. The11#coalgob has accumulated a large number of CO. In mining, the negative pressure of the12#coal seam is greater than that of the11#coal seam. So CO is easy to pass through theleakage channel between the two coal gobs. In order to prevent CO into the12#coalgoal, we should increase ventilation pressure of the12#coal seam face. However, if thepressure is too strong, a lot of fresh air will be drove into the gob, causing thespontaneous to self-combust. In addition, traditional elevating pressure methods aremanual, inefficient and poor accuracy. Therefore it is necessary to make the pressure ina reasonable range.Using the basic theory of spontaneous combustion of coal, we calculate the rangeof the differential pressure sensor such that the existence of air leakage whose amountdoes not cause coal spontaneously combust. The pressure values can be measured by thedifferential pressure sensor and the CO concentration can be measured by the uppercorner CO sensor. We use the frequency control technology to automatically adjust fanspeed till the pressure difference in the two ends of the air leaking area falls in the rangeof the set value.In the automatic voltage-sharing fire protection system, the implementation ofautomatic frequency control methods. The necessary equipments include PLC, fan,motor, frequency changer, differential pressure sensor, and gas concentration sensor.We also connect the wiring of the system hardware and complete PLC softwareprogramming.The automatic voltage-sharing fire protection system provides remedy for thedrawbacks of the methods of empirical and qualitative analysis. It enhances safety andeconomy of the voltage-sharing fire protection technology and makes it both morestable.