Study On The Penumatic Separating Method For Lotus Seed Kernel And Contaminants

The quality of separating process for mixtures determines the whole production efficiency and quality, thus it has significance in the processing of agriculture product. After hulling processing of lotus seed, the mixtures of lotus seed kernel and lotus seed shell can be yielded, therefore, the separating process for shell and kernel would be necessary. In this thesis, a pneumatic separating method which utilized negative pressure was proposed to separate lotus seed kernel and shell. Based on the theoretical analysis and test of aerodynamics characteristics, the aerodynamics characteristics and separating processing parameters of lotus seed mixtures were obtained. The result of this study can be taken as a design reference for the research and development on separating equipment for lotus seed kernel and contaminants. The main research contents are as below:1. The study on the shape parameters and physical properties of the mixtures. The shape parameters, thousand-grain weight, density parameter, mass distribution and moisture content of lotus seed shell and kernel in the mixtures were tested.2. The study on the aerodynamic characteristic research of the mixtures. The ranges of theatrical suspension velocity of each constituent were calculated. Based on the suspension velocity test-bed(type PS-20), the suspension velocity of each constituent was tested. According to the comparison of test results and theoretical calculation results, the shape correction coefficient of products was corrected. Based on the ranges of actual suspension velocity of the kernel and shell, the range of suitable air flow velocity for separation was confirmed as 7.865-11.230 m/s.3. A pneumatic separating method was proposed. The separation form and structure of the separation channel were confirmed, and the force and motion analysis of particle that moves in the separation channel were carried out. A particle motion trajectory simulation of each constituent was carried out by the software-ADAMS, and the feasibility of pneumatic separating method to separate lotus seed kernel and contaminants was verified.4. The pneumatic separating device for lotus seed kernel and shell had been designed and the performance test was carried out. According to single factor test, the effect law of each factor on test index was analyzed; The processing parameters of the device, which was identified and corrected by the orthogonal test, were as follows: inclination angle of separation channel was 35°, inclination angel of inlettube was 60°, air flow velocity of separation channel was 7.88 m/s, length of inlet tube was 220 mm(length-diameter ratio was 5.5), and feed rate was 6 grains every time. Verification test on the optimum scheme was carried out and the result showed that the separating ratio could reach to 98.283%. Finally, three-factor linear orthogonal regression test was performed, and regression equation between test factors and test indexes was established.