| China is a big country of breeding in the world.Feed is the material basis of breeding industry,which can guarantee animal health and promote animal growth.With the development of extrusion and liquid additive technology in feed processing,vacuum spraying of expanded feed can increase the oil content in aquatic feed,which is of great significance to improve the quality of aquatic feed.Combined with the physical characteristics of the expanded feed,this paper carried out the design and analysis of the overall structure and key components of the vertical conical vacuum spraying machine.The specific research contents are as follows:（1）The contact parameters of discrete elements of feed particles were calibrated by means of EDEM and bench test.The results are as follows:the coefficient of static friction between particles is 0.47,the coefficient of rolling friction between particles is 0.08,the coefficient of collision recovery between particles and particles is 0.58,the coefficient of static friction between particles and steel is 0.54,the coefficient of rolling friction between particles and steel is 0.05,and the coefficient of friction between particles and steel is 0.60.（2）The overall structure design of the vertical conical vacuum spraying machine was carried out.The structure and process plan of spiral conveying and top nozzle spraying were worked out.Through theoretical calculation,the operating parameters of the vacuum pumping system are determined as follows:the ultimate pressure of the pump is6?102-Pa,the maximum air volume is 0.12m3/min,the power is 0.37kw,the pump speed is 1400 r/min,the weight is 27kg,and the vacuum pumping time is 91s.（3）Three key parts of the vertical conical vacuum spraying machine are the screw conveying shaft,the nozzle and the conical tank.The structure of the screw conveying parts with double helix variable pitch,the arrangement of the nozzles and the manufacturing materials and thickness of the conical tank are analyzed.（4）The simulation experiment of spiral transport based on EDEM was carried out.The test results show that the conveying efficiency is significantly improved in the process of the helical conveying shaft speed increasing from 90r/min to150r/min,but the growth rate of the conveying efficiency is gradually reduced in the process of the helical conveying shaft speed increasing from 150r/min to 210r/min,and there is little difference in the conveying efficiency at three speeds from150r/min to 210r/min,however,at the speed of 150r/min,the spiral conveying shaft has better throwing performance.The optimal working speed of the vertical conical vacuum spraying machine designed in this paper is determined to be 150r/min.（5）The trial manufacture and bench test of the vertical conical vacuum spraying machine were carried out.The test results show that the vacuum spraying machine designed in this paper is reasonable and reliable in structure and has good performance under better working parameters. |
