The Study Of Vibratory Noise Mechanism Of Ball Mill

Ball mills are large-scale crush equipment, which were used to crush material in chemical process, steam electric power generation, metallurgy, cement production, etc. In working state, the noise of ball mill affected the health of people, decreased the efficiency, influenced the production. So the study of the noise control technique of ball mill is of important significance. To make the scientific and selective measures and realize them, the mechanism of vibratory noise of ball mill should be understood before dealing with the noise of bill mill.In this paper, the main objective is the drum of the ball mill. The vibration of drum of ball mill was analyzed when subjected impulsive load, the impulsive frequency of the drum was calculated. By FEM, the six mode shapes in vibration were got. As a result, the natural frequency of the ball mill was much higher than the working frequency, so the resonance will not occur. In the basis of FEM, the BEM software SYSNOISE was used to calculated the radiation sound field of the drum, and the distribution of sound field was got.As a resultant, the sound field of the ball mill drum has wide frequency, and the acoustic pressure level was highest in middle frequency. In general, the sound field of noise is irregular. According to the result of the vibration of ball mill and the sound field above, we got the measures of the ball mill noise control. First, the damping bedding was used in the noise reduction. Second, the new type sound insulation enclosure was used to decreased the radiation of the noise. Through the two methods, the noise reduction amount is up to 26.4 dB. The mechanism of vibratory noise which was got by analysis and the measures of noise reduction were more selective and accurate than the traditional pure noise reduction, and the effect was much in evidence. They also can give the theoretical basis for the design of low noise ball mill.