Study on Noise Control of Portable Pesticide Fogger

摘要

A portable pulse fogger, in which the fog will be generated by inducing pesticide into the pulse-jet engine's exhaust tube that is full of high temperature and high speed exhaust gas, can be applied in disease and insect control in forestry, greenhouse and sanitation with the advantages of high application efficiency and low environmental pollution and the disadvantage of excess noise. In the paper, the experimental study of gas intake noise control, according to the engine's working principle, had been finished. 6 noise testing positions were set around the engine. As shown in the study, before noise reduction, the maximum noise value were 114.4 dB(A) of gas intake, 109.8 dB(A) of exhaust outlet and 102.3dB(A) of lateral combustion chamber. After noise reduction with m7, m11 and m15 reactive mufflers, the noise reductions were maximum 9 dB(A) of gas intake, minimum 1.4 dB(A) of exhaust outlet and 5-7 dB(A) of other testing positions. After noise reduction with fiberglass felt of 8, 12 and 16 layers gradually the noise reductions become more and more. The maximum reductions were 5 dB(A) of the gas intake and exhaust outlet and 4dB(A) of other testing positions. According to the noise reduction frequency characteristics, for reactive muffler, it was not only that the noise reduction effect was better than of resisting muffler at low frequency, but also the total noise reduction was more.