Study On Exhaust Characteristics And Structure Optimization Of Exhaust Hood In Welding Workshop

At present,due to the unreasonable design,unscientific process layout and nonstandard production operation,the metal welding workshop is prone to lead to the excessive concentration of smoke and dust in the welding workshop,which not only seriously affects the health of workers,but also reduces the production efficiency.In January 2012,in the newly revised law of the people’s Republic of China on the prevention and control of occupational diseases,the prevention and control of "high-risk dust" was included in article of the law.Therefore,it is of great practical significance and application value to study the characteristics of smoke and dust in welding workshop and develop efficient emission facilities.The author of this paper has carried out field test in an electric welding workshop in Yantai city.During the working period of workers,using light house laser particle counter to sample,the particle size distribution of the dust source in the welding station of the workshop and the characteristics of the number and concentration of particles with different particle sizes under various working conditions were measured.At the same time,TSI anemometer was used to measure the speed of the exhaust hood.After analyzing the measured data,it is known that the particle size distribution of the particulate matter in the welding workshop is mainly accumulated particles with a particle size of<1.0 μm.The exhaust system can effectively remove the accumulated particles and coarse modal particles in the dust.The maximum number of welding fumes in the workshop is 1.58×103 pieces/cm3,the maximum mass concentration is about 0.66mg/m3,and the number concentration is about 1.22×107 pieces/min.In this paper,the flow law of dusty smoke is simulated,and it is found that changing the speed of the exhaust port of the exhaust hood,the length of the outer curtain and the height of the exhaust hood from the table can change the wind speed and collection efficiency of the control point,and the dimensionless ratio is Optimize the key parameters of the exhaust hood.According to the control point wind speed and the collection efficiency,optimization schemes were obtained respectively,and the two schemes were compared.Finally,the structural optimization scheme of the exhaust hood was determined as follows:the exhaust hood wind speed was 4.80m/s,and the dimensionless ratio k*>0.54.The optimization plan provides guidance for energy saving and consumption reduction,and improving the efficiency of the exhaust hood.