Study On Cleaning Device Of Peanut Picker With Double Air-suction Inlets With Vibration Screen

Peanut was an important oil crops in the world and in china. However, after peanut pods were picked by peanut picker and harvester with two-stags, a common problem in the peanut picker and harvester which the cleaning index such as the loss rate and the impurity rate were high. For the purpose to improve the cleaning performance including reducing the loss rate and impurity rate of peanut picker and harvester, based on the specialized research fund for the doctoral program of higher education project of "Principles of main mechanisms and key technology of peanut combine with pickup head and thresher"(project number: 20122103110009), the national natural science fund of "research on mechanism of peanut shell and mechanical damage and shell technology with low damage"(project number: 50775151).The mainly planting peanut crops in the area of Liaoning province were selected as the research object, based on the study results on the floating velocities of different extraction components of peanut pods, cleaning device of peanut pods with double air-suction inlets with vibration screen were studied. The structures of cleaning device were formed by the pneumatic clearing system with double air-suction inlets installed on both sides of centrifugal fan and the vibration cleaning system with a vibration screen without quick-return motion. The structure and parameters of key parts were analyzed and studied in theory. And the cleaning device was developed and its performance test and study was conducted under peanut harvest production condition. The optimum structure parameters of the cleaning device were determined, providing some reference for the further research of peanut and related materials in the cleaning device.This paper based the review on domestic related literature, by using the method of combining theory with test, the main research contents and conclusions were as follows.1) The mixture composition of peanut pods picked materials and its cleaning characteristic were studied. The peanut picking composition proportion and floating velocities about different varieties of peanuts were obtained, the relationship between the components of floating velocities and different moisture content was analyzed. The data of three axis dimension, density and friction coefficient of peanut pods and crushed stems were got. Providing a theoretical basis for the choice of the material of screen, the tilt angle of vibration screen, the cleaning airflow velocity range of air-suction inlets.2) The contrast research on floating velocities of different extraction components of peanuts pods was conducted, and the overall scheme of the cleaning device was determined. A new cleaning principle on cleaning device of peanut pods was put forward and its structure was designed by modular structure which constituted by double air-suction inlets and vibrating screen. And the key parts including vibrating screen, transmission mechanism, cleaning fan and transmission system were designed.3) The dynamics properties on peanut pods in the process of vibration cleaning were analyzed and its dynamics differential equation of cleaning materials in the sieve surface was established. The limiting condition in the motion of cleaning materials in the process of cleaning and the main factors of cleaning device influenced the vibration cleaning processing were studied. On this basis, the structure parameters of vibration cleaning system were optimized by the virtual orthogonal experiment. According to the optimized parameters and using the software ADAMS, the mechanism on vibration conveying of peanut pods and vibration removing of soils which adhering in the surface of peanut pods in the process of cleaning were simulated and analyzed.4) The airflow distribution laws for the air-suction inlets were studied by numerical simulation based on the software CFD. The numerical simulation model of the airflow field in the front and behind air-suction inlets were established, by the change of the value of negative pressure in the exit of air-suction duct and the height between the air-suction inlets and screen surface, the law of motion in airflow field was analyzed and the critical clearing airflow velocity range in the front and behind air-suction inlets were determined.5) The cleaning device of peanut pods with double air-suction inlets with vibration screen was developed. The loss rate and the impurity rate were selected as the test indexes to measure the performance of cleaning device. Three parameters which mainly influenced the test indexes, including rotating speed of crank, height of air-suction inlets, and rotating speed of fan as test factors and the performance test for the cleaning device were conducted by RSM. A quadratic orthogonal rotary regressive experimental design was employed to develop the second order polynomial regression models, which found out the primary and secondary order of test factors influenced the test indexes and established a mathematical model between the input and output parameters by using the analysis method of subtracting variable to analyze the test factors effect on test index. And then, the main parameters of cleaning device were optimized through the theory and method of multi objective nonlinear optimization. The prototype of cleaning device was improved and optimized by the analysis of performance test results, and the validated cleaning test of peanut pods was conducted according to the actual needs in the subsequent processing of peanut pods.