Research On Associated Pneumatic Precision Metering Device For Rapeseed

So rape has great comprehensive utilization benefit and good market prospect, which occupies an important position in agricultural production of our country, for the reason that planting of rape should be made more widespread. But now, for the planting of rape, in the two pattern including transplanting and tradition direct seeding, there are a few shortcomings, such as need lot of labors and thinning, that hinder the development of our country's rape industry. Rape precision sowing can make up these shortcomings, so this article developed the associated pneumatic precision metering device for rapeseed based on researching the present study situation. This device aims at the features of rapeseed, it can make use of negative pressure to finish seed-filling, make use of positive pressure to finish seed-clearing and make use of positive pressure to finish dropping seed.This article researched the working principle of the precision metering device; designed the structures of the device, and established its three-dimensional model using Pro/E; completed the kinematics and dynamics analysis of rapeseed at the work process; analyzed flow field of the metering device using ANSYS CFX; completed trial production of the device; completed the experimental studies on JPS-12 metering device test-bed, completed orthogonal experiments on the base of single factor experiment.According to the result of theoretical analysis, the diameter of the bottom of the type hole should be 1.3 mm, the negative pressure of the metering device should be 1.7kpa. The results of ANSYS analysis show that the flow fields of the metering device are stable; according to the results, when the angle of the type hole is 60°,it can facilitate seed-filling; when the nozzle angle is 45°,it can facilitate clear seeds. The results of single factor experiments show that the negative pressure,positive pressure,the angle of the nozzle,speed have significant effect to the performance of metering device; the results of range analysis for orthogonal experiments show the order according to the significance to performance of the metering device: positive pressure for clearing seeds>the nozzle angle>negative pressure>speed. And when the speed is 13r/min, the negative pressure is -1750pa, the positive pressure is 470pa, the nozzle angle is 40°,the performance of the device is optimum, at this point, the qualified rate is 80.89%. The results of the study show that this metering can basically achieve precision seeding of rapeseed, which can save lots of hour and labors,and the seed spacing is uniform.