Research Of Acoustic Signal Acquisition And Analysis System For Fused Magnesium Furnace

Fused magnesium is a sort of good refractory material that has many good characteristics such as high melting point, resist corrosion and good insulation. Fused magnesium is applied in metallurgy, national defense industry, nuclear industry and so on. At present, Fused magnesium furnace is the main equipment to produce fused magnesium. The external disturbances and the terrible field condition exist during the smelting process, in addition, the fused magnesium furnace is a controlled object with strong nonlinearity, time variation and strong coupling, so different operating strategies needed in different smelting states. Now the judgement of smelting states mainly depends on the operation personnel's subjective experience, it is difficult to judge the smelting states accurately and not conducive for automatic control, energy consumption and emission reduction, in addition, it lowers the products'quality.This thesis is supported by national high technology research and development program of China(863 Program). This paper, taking the factory's fused magnesium furnace which exists in Ying Kou city as the research object, deducing the arc sound signal's mathematical expression based on the relationships between arc sound signal and the arc current and arc voltage, establishing the acoustic signal's acquisition position, using the NI data acquisition card to set up the data acquisition hardware platform and designing the acoustic signal acquisition and analysis system with the Lab VIEW software.The acoustic signal acquisition and analysis system for fused magnesium furnace designed in this paper has some function such as user login, data acquisition, data storage, waveform display, time-frequency analysis and remote control. The system acquired the acoustic signal and arc current in different smelting states during the smelting process. The dbO4 wavelet soft threshold denoising method was used to analysis the acoustic signal and draw the wavelet time-frequency diagram with Lab VIEW and MATLAB mixed programming. Finally, the paper concluded the smelting states'criterions through the sound intensity, three phase current and acoustic signal's wavelet time-frequency characteristics in different smelting states during the smelting process. The smelting field experiment proved that the criterions can effectively judge the different smelting states, improve the product quality and provide a new way for fused magnesium furnace's automatic method.