Research On Positive And Negative Pressure Combination Precision Metering Device For Rape Seed

Rape is an important oil plants, which is the fifth farm crop behind paddy rice, wheat, corn, soybean. Its planting area has already exceeded 1,100 million acres, and its planting area and the total yield share about 27% of the world. So china is the biggest yield area of rape in the world. The rape benefits to maintain the farmland, and it has little conflict with other crops on soil. So it has a big potential to extend the area in our country. However, the management scale of rape production is small currently in our country, and the country labour force is shortage and the rate of production is low, because most of the country labour force goes out to work,. The rape production still adopts manual work or half mechanization for the main work method. The whole production has big labor intensity, much loss, high production cost, low output benefit, which restricts extending of the rape production scale and the exaltation of output benefit. So it is imperative under the situation to develop the mechanization of rape production. For improving the mechanization degree of rape production, guaranteeing the rape seed to distribute most reasonablely in the field, saving the seed, reducing the energy in spacing seedling in the field, guarantee the steady and high production of the rape, it has become imperative under the situation to realize precision and direct seeding technique of the rape.According to the analysis of planting mechanization technique of the rape and research status in quo of precision metering device in existence at home and abroad, the article has developed a positive and negative pressure combination precision metering device of rape seed. The metering device is applicable to the rape seed characteristics which has small diameter and high oilness rate. It has the character of integrating air-suction and air-exhaust one to realize precision and direct seeding of the rape. The research contents are as follows:1. The physical and mechanical properties were measured and analyzed by test. It included the physics characteristic and dispersing characteristic of three kinds of important rapes species, which concluded that the most of those seeds ranged froml.5 to 2.2mm by normal distributing, the size of three axes had little discrepancy and regular shape, the sphericity degree was between 86% and 99%, and rapeseed had good mobility which related to the regular spherical appearance.2. The theories analysis and structural integration design of metering device were completed, and the metering device was manufactured. And the kinematics and dynamics analysis of seed at the work process were developed by the numbers. The mostly configuration parameter of the metering device was confirmed. The main factors affecting on the feeding performance are analyzed respectively, such as vacuum degree, sucking hole diameter, bore number and the linear plate speed of roller, and so on.3. By the use of ANSYS 10.0/FLOTRAN software, two directions model of three types of different bores structural were constructed, and the solution analysis was completed at the same time. It concluded that the type of bore had a big influence to the current of air field, when the vacuum degree was 1.5 KPa, the cylinder type construction bore has a good stability. If the air chamber's depth was deepen, the air chamber inside flows would be more stability. So it's benefit to the feeding of rapeseed.4. An orthogonal test was completed on JPS-12 metering device test-bed. The results showed metering device planted in good. Through poling analysis of the relative importance of factors the optimal parameters were obtained, and the best combination is A₁B₃C₁.