Search Results (4)

To improve the uniformity and precision of soybean seeding, this study designed a high-speed airflow-assisted seeding system for the pneumatic drum-type high-speed precision seed-metering device. The system accelerates seed delivery through airflow and ensures precise seed placement using a seed press wheel. Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) coupling simulations were employed to analyze the seed motion trajectory, collision process, and velocity changes. Key design parameters of the airflow-assisted delivery system were optimized, including a tube diameter of 16 mm, a curved section radius of 80 mm, a seed delivery angle of 33.65°, and a press wheel diameter of 254 mm. The simulation results indicated that the relative position between the seed delivery tube and the seed drum significantly impacts seed trajectory and uniformity. Lowering the tube to align with the seed velocity direction minimized collisions and enhanced seed spacing consistency during high-speed operation. Increasing inlet air pressure improved seed distribution uniformity by accelerating seeds within the tube, reducing travel time and collisions; a 500 Pa pressure increase raised the maximum flow velocity by approximately 5 m/s. However, seed acceleration exhibited diminishing returns: pressure increase from 2.5 kPa to 3.5 kPa increased seed speed by 2.1 m/s, while a further increase to 4.5 kPa only added 1.1 m/s. The optimal inlet pressure for efficient energy transfer and seed acceleration was approximately 3.5 kPa. The press wheel played a crucial role by dispersing the impact force when seeds contact the soil, which achieved high capture rates above 94.0% across the seed drum rotary speed range of 11 to 19 rpm. This research provides theoretical and experimental support for the optimization of high-speed airflow-assisted seeding systems, offering significant practical value for large-scale agricultural production by enhancing seeding efficiency and quality. Full article

In view of the problem that the qualified index of grain spacing deteriorates during high-speed operation of the pneumatic corn seed dispenser, a new method of homologous dual-action positive-pressure-assisted seed filling and seed release is proposed, and a pneumatic corn seed dispenser with assisted inflow filling is designed. The structure and working principle of the seed dispenser are explained, and a theoretical analysis is carried out on the seed filling and seed release process in the seed guide tube. The key structural parameters of the conical deflector-groove seed metering disc and the homologous airflow-assisted seed release mechanism are determined. The test factors were working pressure and operating speed, and the evaluation indicators were the qualified particle spacing index, missed sowing index, resowing index, and qualified particle spacing variation coefficient. A full-factor bench test was carried out, and the test results showed that when the sowing speed was 6 km/h and the working pressure was 5 kPa, the qualified particle spacing index was 96.37%, the missed sowing index was 0.30%, the resowing index was 3.33%, and the coefficient of variation in the qualified particle spacing was 17.37%. The results of the field test showed that when the operating speed was 6 km/h and the working pressure was 5 kPa, the qualified particle spacing index was 95.30%, the missed sowing index was 2.33%, and the resowing index was 2.37%. All indicators met the technical requirements for precision single-seed maize sowing. Full article

Aiming to solve the problems of the poor uniformity of seed flow discharge and serious damage of traditional straight grooved wheels to improve the performance of air-assisted maize high-speed precision seed metering devices, a staggering symmetrical spiral grooved feeding wheel with maize seeds was designed. To explore the influence of the spiral groove inclination angle and the length of the staggered symmetrical spiral groove feed wheel on the uniformity of seed flow discharge, the spiral groove length l and the spiral groove inclination angle ρ were used as the experimental factors, and the variation coefficient of the increase in seed, a full-factor simulation test was carried out for the test indicators, and it was found that both the inclination angle and the length of the spiral groove have an influence on the uniformity of seed flow discharge, and the influence of the inclination angle of the groove is more significant. Comparing the force of a single seed in the traditional straight grooved wheel and that of the spiral feeding wheel, it is found that the staggered symmetrical spiral grooved feeding wheel can reduce the damage of seed fertilizer. Through a bench test, the spiral groove length was found to be 50 mm, and the groove inclination angles are 30°, 45° and 90°. The test results show the variation trend and simulation results of the fluctuating coefficient of variation of the seed flow discharge in the bench test. The trend of change is basically the same. The inclination angle of the spiral groove is 45° and the uniformity of seed flow discharge is the best when the groove length is 50 mm, indicating that this structure can effectively improve the uniformity of material discharge, and the variation coefficient of seed flow discharge fluctuation is 3.12% and the seed breakage rate is 0.69%. Through the seeding performance test, it is verified that the staggered symmetrical spiral grooved feeding wheel can improve the seeding performance of the pneumatic high-speed precision metering device. When the metering device runs smoothly, the qualified rate reaches more than 90%, and the leakage rate is reduced to 0%. Therefore, the results of this study can provide a reference for research on uniform seeding, drill seeding and the uniform application of granular fertilizer. Full article

In view of the problems of a poor seed-filling state and poor seed-cleaning effect of a precision metering device under high-speed working conditions, an inside-filling air-assisted high-speed precision maize seed-metering device was designed, fabricated, and evaluated. The overall structure and working principles of the seed-metering device are explained. Theoretical analysis and parametric design of the key parts, such as the horizontal stirring notch seed-metering plate and the wheel seed-cleaning mechanism, were carried out. The main factors that produce multiple seeding problems were studied. The forward speed (FS) and working pressure (WP) of the seed-metering device are determined as the main factors affecting the seeding performance. A quadratic orthogonal rotation combination experiment was designed. The relationship between influencing factors and performance indexes was constructed using the Design-Expert 10.0.7 software. The response surface method was used to optimize the experimental results. The results of the bench validation experiments showed that the seeding performance of the seed-metering device was excellent when the FS of the seed-metering device was 13.10 km/h and the WP of the seed-metering device was 4.75 kPa. The results of the bench comparison showed that the seeding performance of the designed seed-metering device was better than that of the conventional air-suction precision seed-metering device. This study provides theoretical and practical references for the optimized design of a pneumatic precision seed-metering device and the sustainable development of grain. Full article