Research On The Vertical Axial Flow Thresher For Soybean Breeding

Breeding experiment is a very effective mean for breeding improved varieties and comparison tests. Breeding mechanization would improve the efficiency of breeding work, reduce labor intensity of breeding operations and liberate the productive forces. Breeding harvest is the final part of breeding experiments, but also the most important part. Plot harvest is different from normal harvest. The area of the plot is very small, and there are a lot of plot in one breeding experiment field. So the breeding harvest should not only avoid mixed seeds a higher productivity, but also have a higher productivity, China’s breeding harvest is still mainly harvesting methods of the hand harvest and common thresher threshing. For hand harvest, the harvest period is very long, easy to be adversely affected farming season, indirect losses, and that poor comparability of test data. The use of common soybean thresher would cause high grain crushing rate, high loss rate, difficult to clean up in the thresher, seed residue, and easily give rise to hybrid seeds, resulting in distortion of experimental data.The paper systematic described the status of the breeding harvest machinery and their features, analyzed the structure of the threshing device, separation device and cleaning system at home and abroad. According to the status of the design and the problems existing in the threshing separation and cleaning system of the breeding thresher and the thresher of soybean breeding is different from others, so it is necessary to conduct theoretical and experimental studies of the threshing separation and cleaning system. The main contents of the policies can be summarized as follows:1) A test bench proposed for measuring the suspension velocity of agriculture materials developed by northeast agriculture university measured the suspension velocities of soybean extraction. According to experimental result, the distribution of suspension velocity of saturated grain was11-17m/s, the distribution of suspension velocity of skin was5-6m/s, the distribution of suspension velocity of40mm stem was7-13m/s, the distribution of suspension velocity of80mm stem was8-14m/s, the distribution of suspension velocity of120mm stem was10-17m/s.we analyze how the factors have any influences to the cleaning system, the ideal wind speed for cleaning is smaller than11m/s.2) The general structural has been designed for the machine, threshing device, cleaning device and so on. The main structural and operating parameters have been computed and analyzed. The solid models of the thresher and the key components were completed by PRO/E software platform. The stress analysis, intensity examination, the structure optimization were carried by ANSYS software platform. The numerical analysis and optimization of the cleaning device and the air blower were completed by hydrodynamics analysis module.3) A central composite rotatable orthogonal experimental design of response surface methodology was employed for finding the optimum combination effecting on the working properties. The four parameters:linear velocity, concave clearance, feeding rate and moisture content were selected as input variables. Cracked grains, impurities, loss of entrapped grains, loss of unthreshed grains, spattered grains and residual grains were selected as response functions. Experimental results indicated that the most optimum combination region of the moisture content was14-20%, the linear velocity was6.5-8.3m/s, the concave clearance was15mm, the feeding rate was2.4kg/min, the cracked grains were less than1%, impurities were less than0.5%, loss of unthreshed grains were less than2%and loss of entrapped grains were less than0.7%. Spattered grains and residual grains were zero.4) The project blueprint was drawn up, the first machine was processed, the performance test and analysis optimization were completed.