Optimization Design And Experiment On Plasma Seed Treatment Device

Plasma seed treatment can improve seed vigor,seed growth,yield and quality.Based on the technical requirements of the plasma seed treatment,a plasma seed treatment device was designed and the related technical parameters were tested.The research results can provide technical support and theoretical basis for the application of seed treatment industrialization.(1)The technical requirements for the overall design of the plasma seed treatment device were proposed by analyzing the plasma generation power under low atmospheric pressure,seed treatment time,and the effect of working gas medium on seed treatment.The batch processing mass was 25 kg,the main operating parameters of the generator power were 0?500 W(adjustable)and the seed treatment time was 10?20 s(adjustable).Besides,two gas distribution methods for a single working gas medium or two working gas mixtures were specified.A plasma treatment scheme was proposed and a completed plasma seed treatment device was designed.The key components such as the plasma generation system,the plenum assembly,the low air atmospheric pressure maintenance system,gas distribution system,and the seed vibration transportation device were designed.(2)The kinematics analysis of the seed vibration transportation device was carried out based on kinematics theory,and the effects of parameters such as feed plate tilt angle,vibration frequency,and vibration direction angle on the movement state of single seed were discussed.The relationship between each parameter and the speed and displacement of single seed transportation was established.Through the experimental verification of the wheat seed vibration transportation test platform,the linear fit of the model calculation result and the experimental value exceeded 84%,which provides a theoretical reference for the vibration transportation state of seed(3)The discrete element method was used to simulate and analyze the movement state of the loose-grained seeds in the seed vibration transportation.The positive correlation between the seed transportation speed and vibration direction angle,vibration intensity and eccentric distance was obtained when the distance of the seed to the plate was 1.84 to 3.06 mm.A regression model between the seed transportation speed and each parameter was established through quadratic rotation orthogonal combination test.The optimum structural parameter was combination vibration direction angle of 30° with eccentric distance of 5 mm.Through the establishment of the wheat seed vibration transportation test platform,the actual speed was consistent with the model calculation speed and simulation test speed.The research results provide a theoretical basis for selecting seed delivery time.(4)Based on the plasma generation conditions and the technical requirements of seed treatment,the design of the operation flow of the plasma seed treatment device was carried out and a design scheme of control system was proposed.The hardware and software of the control system were designed using PLC,which guarantee human-machine interaction,the maintenance under low atmospheric pressure,plasma generation stability,seed transportation,temperature feedback adjustment and other functions.The whole-machine trial of the plasma seed treatment device was developed,and the temperature requirement of 15?20 0C was achieved.(5)The indoor seed germination tests of wheat,alfalfa and astragalus membranaceus seeds after being treated by plasma seed treatment device were carried out and optimum combination parameters of plasma generation power,seed treatment time,and working gas medium were obtained.Parameters of wheat seeds were 80 W,15 s and helium medium,respectively.Parameters of wolfberry seeds were 40 W,15 s and helium medium,respectively.Parameters of astragalus membranaceus seeds were 180 W,20 s and air medium,respectively.Through the experiments of germination rate and germination potential,it shows that the effect of the plasma seed treatment device is significant.(6)The field trials of wheat,alfalfa and astragalus membranaceus seeded after being treated by plasma seed treatment device were carried out.The yields of first,second,and third generation wheat increased by 8.12%,5.75%,and 3.81%,respectively.The a ount of alfalfa with the larger stem(3?4mm)increased by 70.59%.The root length and head diameter of astragalus membranaceus increased by 20.95%and 30.72%,respectively.Field trials show that the plasma seed treatment device has a broad industrial application prospect.