DEVELOPMENT OF NOISE REDUCTION METHOD FOR GRAIN DRYERS

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The noize of 43 points around a unit dryer and 23 points in a country elevator were recorded.In the laboratory tests we used FFT analyzer to analyze the frequence of sound before and after using reverse sound for the measuring points. we took seven samples, the 0,45,90,135 and 180 degrees of angle and the distance of 1,5m and 3.0m around the noise source and the reversed noise source of the speaker were measured and analyzed by the FFT.The results indicated from about 10 (dB) to 20 (dB) reduction of noize level by the reversed noise generation. The reversed noise by a speaker in the exhaust duct for dryng air actually reduced the exhaust noise by about 2 dB.The similation of noize cancelation by reversed noise were developed, and using the recorded measured noise source the noise reduction characteristics similar to the preseding experimental results were obtained. The simulation was also suggestive of some effective method of noise control.