Study on key technologies of coal mine main fan automatic switchover with ventilation unceasing

The currently-used mine main fan switchover is to stop the working fan first and then to start standby fan, which makes underground ventilation interruption during switching, and it is liable to cause gas concentration exceeding limits in high gas mine and threaten mine production safety. Based on the thought of changing the fan on standby from cold standby to hot standby before switchover, a novel way of main fan switchover aiming at ventilation unceasing with the aid of ventilation network switchover is put forward. From the influence on ventilation system, ventilation interruption throughout switchover formerly can be improved to air flow rate fluctuation during ventilation network switchover only. Therefore ventilation stability during main fan switchover can be realized and potential safety hazard of gas concentration exceeding limits is eliminated effectively. According to the relationship between the boundary condition for the safety running of main fan and the stability of ventilation system air flow rate studied in this paper, based on four louver air-door cooperative regulation, a control strategy for ventilation network switchover to realize ventilation unceasing during main fan switching was given. Then an automatic control system has been developed with PLC. Practical operation indicates that the way of main fan switchover presented in this paper can deal with the deficiencies of the way currently-used, and it is important and significant for the safety of mine production.