Effect of vibration parameters of vibrating screen for harvester on adhesion characteristics of threshed mixtures with different moistures

Abstract: Rice is one of the three major grain crops in China. Cleaning is one of the most important processes in rice harvesting, and the performance of vibrating screen and vibrating board has significant effect on cleaning operation. However, rice has high moisture content during harvest, its surface is moist and sticky, and it is easy to stick to vibrating screen and vibrating board. Therefore, it is great significance to study the effect of vibration parameters on interface adhesion characteristics of rice threshed mixture. In this paper, a linear vibration tested was designed and checked. The sieve substrate was made of 304 stainless steel. 2 kinds of rice threshed mixtures with different moisture content were selected as test objects, The moisture content of grain, straw and impurity in threshed mixtures with low moisture content was 18.76%, 54.68% and 32.18% respectively. The moisture content of grain, straw and impurity in threshed mixtures with high moisture content was 24.56%, 79.04% and 47.73% respectively. Vibration amplitude, vibration frequency and vibration angle were selected as test factors, and adhesion in unit area was used as test index. Through single factor test, the influence law of each factor on the test index was analyzed, and the better level of each factor was determined, that is the vibration amplitude was 40-60 mm, the vibration frequency was 5-7 Hz, the vibration angle was 40°-60°. Then, the design and analysis of orthogonal test were carried out in this paper, the mathematical models for test index of 2 kinds of threshed mixture with different moisture content and the order of main and secondary factors affecting the test index were obtained. The influence of vibration parameters on the adhesion in unit area of threshed mixtures with low moisture content in descending order was the vibration angle, vibration amplitude and vibration frequency. The influence of vibration parameters on the adhesion in unit area of threshed mixtures with high moisture content in descending order was the vibration frequency, vibration angle and vibration amplitude. The interaction between vibration amplitude and vibration frequency was found, and the response surface analysis was carried out. The trend of the response surface of 2 kinds of threshed mixture was basically same. The influence of moisture content on the adhesion characteristics of threshed mixture was obtained. Through the comparison test of 2 kinds of rice threshed mixtures, it was found that moisture content was an important condition that affected the interface adhesion properties, and the higher the moisture content, the more serious the adhesion was. The optimum parameter combination for adhesion in unit area of threshed mixtures with low moisture content was that the vibration amplitude was 60 mm, the vibration frequency was 6 Hz, and the vibration angle was 50°. The optimum parameter combination for adhesion in unit area of threshed mixtures with high moisture was that the amplitude was 50 mm, the vibration frequency was 7 Hz, and the vibration angle was 50°. Verification test results showed that the regression model was reliable and the relative error was less than 10%.