To solve the problems that the borehole depth is shallow and the drilling efficiency is low during the gas drainage drilling in soft coal seam with current cuttings removal method, a new technology of reverse circulation pneumatic cuttings removal is proposed. The working principle of reverse circulation pneumatic cuttings removal is analyzed, and the kinetic equation of cuttings in the inner hole of the drill pipe is established. Through experiments, the pressure drop in the drill pipe is measured to reveal the effects of air velocity, cuttings mass flow rate, and cuttings particle size on the pressure drop in inner hole of the drill pipe. When the cuttings mass flow rate is constant, the pressure drop increases with the increase in air velocity. When the air velocity is constant, the pressure drop increases with the increase in cuttings mass flow rate. At low air velocity, the pressure drop of cuttings is primary. As the air velocity increases, the pressure drop ratio of cuttings decreases. Under the same conditions, the order of pressure drop with different particle size cuttings is coarse cuttings > medium cuttings > fine cuttings. Empirical equation of pressure drop coefficient of cuttings is established, which is in good agreement with the actual data.

The fault diagnosis of vibration exciter rolling bearing is of great significance to maintain the stability of vibration equipment. When the crack fault of the bearing occurs, the effective fault feature information cannot be extracted because the fault feature information of vibration signal is interfered by the noise around the vibrator. To solve this problem, a fault feature recognition method based on genetic algorithm–optimized Morlet wavelet filter and empirical mode decomposition is proposed. The Morlet wavelet filter optimized by genetic algorithm was used to filter the vibration signal, and then the empirical mode decomposition was applied to the filtered signal. In the envelope spectrum of the reconstructed signal, the characteristic frequency of the rolling bearing crack fault of the vibration exciter could be found accurately. Through simulation and experiment, it is proved that this method can provide theoretical and technical support for the crack fault diagnosis of vibration exciter rolling bearing.