Study On The Soft-sealing Dust Control System Based On Transverse-flow Air Curtain And Its Performance

On account of certain technological requirements,it is difficult for some industrial processes that generate dust to be sealed in a fixed pattern and ventilated for dust discharge,mainly automatic welding,pressure casting,wood processing,and crop production,resulting in serious dust escape,which is an important reason for safety accidents and frequent pneumoconiosis.Up to now,there is no effective measures to achieve dust efficient collection.It is an innovative application to apply air curtain to the collection of dust in the dust producing links that could not be sealed in a fixed pattern.Nevertheless,the air curtain generator has specific application scenarios with strict volume limitation and almost no detailed experimental data are available for reference.In addition,the experimental data and technology of using air curtain to collect dust from open dust sources are not complete,and relevant experimental research and equipment development need to be carried out.This study focused on small-volume transverse-flow air curtain generator,investigated the effects of three structural parameters,namely the cross-sectional area of the air curtain generator,the air supply groove and the diversion blades,on the uniformity,diffusivity and deviation of the formed air curtain.Results reveal that by increasing the cross-sectional area,the static pressure difference in the air curtain generator along the full-length direction could be reduced and the uniformity of the air curtain could be enhanced.In addition,the uniformity of air curtain could be improved by the shunt action and diversion action of the diversion blades.Under the premise that the constraints of the volume upper limit of the air curtain generator had to be satisfied,the optimal cross-section diameter of the air curtain generator was determined to be 110 mm.The use of the air supply groove with an appropriate length could effectively suppress the turbulence of the airflow at the outlet,weaken the entrainment effect of the jets on surrounding air and make the formed air curtain more concentrated.This study proves that an air supply groove with a length of 35 mm could satisfy the present requirements.In addition,the diversion blades could play the role of mechanical diversion so as to strengthen the turning of airflow and cope with serious deviations of the air curtain.In this study,using diversion blades with a spacing of 60 mm,the formed air curtain was nearly horizontal.Therefore,the key design parameters of the cross-flow air curtain generator are proved,which has the characteristics of high uniformity,low diffusion and deviation of the air curtain in asmall volume,and is about 30% smaller than the diameter of the existing air curtain generator with the minimum volume.Secondly,based on the development of cross-flow air curtain generator,this paper studied the range and the barrier scale of interference lateral wind speed of cross-flow air curtain under different jet speed,which provides data support for the selection of air curtain range and the interference lateral wind speed limit that could be effectively blocked.The results show that with the increase of the distance,air curtain velocity first decreased rapidly,then decreased slowly until the velocity was 0;with the increase of air curtain outlet velocity,the barrier effect of air curtain on the interference lateral wind is gradually significant,and an air curtain outlet velocity of6.4 m/s could generally meet the needs of practical application.Then,based on the dust control theory of rotary air curtain,a soft-seal dust control system is developed.The flow field characteristics in the area where dust was generated and the performance of the developed sealing system in controlling fine smoke dust were qualitatively analyzed using a tracing experiment with smoke dust.Tracing experimental results on leaf powder qualitatively reveal directional dust control of large dust particles.Moreover,the dust control efficiency was evaluated under different conditions to quantitatively investigate the effects of air curtain outlet velocity,exhaust-to-pressure ratio,and jet angle.The results show that with a greater air supply and air suction rate,the airflow exhibited a more obvious entrainment effect and stronger dust exhaust and discharge,and simultaneously,the formed tracing smoke column had a clearer boundary.For a soft-seal dust control system with the length*width of 1.0*1.0m,at an air curtain outlet velocity of 6.27-8.39 m/s,a stable air curtain was formed,which achieved remarkable dust control at an exhaust-to-pressure ratio of 0.8-1.0.With an increase in the air curtain jet angle,the dust control efficiency of the system first increased but subsequently decreased.In the present study,the appropriate air curtain jet angle was 10-20° for the developed soft-sealing system.In conclusion,when the air curtain outlet velocity,exhaust-to-pressure ratio,and jet angle were 6.27 m/s,0.6,and 15°,respectively,the dust control efficiency of the soft-seal dust control system of 1.0*1.0m was 92.6%.At present,the soft-sealing dust control system is being used in Anyang cigarette factory.This paper has 56 figures,16 tables,84 references.