Study on Performance of Concentric Threshing Device with Multi-Threshing Gaps for Rice Combines

Yanbin Liu,Zhan Su,Yaoming Li,Tao Zhang,Zhenwei Liang,Mingsen Huang,Lipeng Chen

doi:10.3390/agriculture11101000

Abstract

S concentric threshing device can improve rice crop separation and transportation capabilities. As one of the main factors affecting the threshing performance of rice combine harvesters, the threshing gap can influence the grain unthreshed rate and the grain damage rate directly. However, the clearance between any threshing cylinder tooth and the concave grid is constant for the traditional threshing device, named the single threshing gap in this paper, resulting in a consistently high total loss rate (the sum of unthreshed and damaged grains). Therefore, multi-threshing gaps are proposed in this paper for the concentric threshing device to solve the above problem. To compare the threshing performance between the single threshing gap and the multi-threshing gaps, the movement process of rice mixture (grain, short straw, and long straw) was simulated using the discrete element method (DEM). The simulation results showed that the separation and transportation abilities of the multi-threshing gaps were not decreased, but the distribution of threshed output mixture was more even for the multi-threshing gaps. Furthermore, a field experiment was also carried out on a combine harvester to compare the total loss rate. The experiment results showed that the total loss rate of the concentric threshing device with multi-threshing gaps was reduced by 0.0593%, which was 5.77% less than the total loss rate of the concentric threshing device with a single threshing gap.

Highlights

Threshing gap is the clearance between the threshing cylinder tooth and the concave grid, which is one of the main factors affecting threshing performance [4]
Su et al [6] proved that the threshing performances of a concentric threshing device were superior
Tofacilitate facilitate adjustment of three threshing a longitudinal axial-flow threshTo thethe adjustment of three threshing gaps,gaps, a longitudinal axial-flow threshing ing cylinder was designed, which could independently adjust the elongation of cylinder was designed, which could independently adjust the elongation of each threshing each threshing rod; it was adopted in provide this study provide basis for field experirod; it was adopted in this study to the to device basisthe for device field experiments

Summary

Introduction

Threshing gap is the clearance between the threshing cylinder tooth and the concave grid, which is one of the main factors affecting threshing performance [4]. Adjusting the threshing gap using a concentric threshing device changes the diameter of the threshing cylinder by adjusting the elongation of the threshing rods [5]. Su et al [6] proved that the threshing performances (the transportation and separation capacities, the distribution of the threshed output mixture) of a concentric threshing device were superior. Strong conveying and separation abilities can effectively prevent the blockage of the threshing device, and the distribution of the threshed output mixture will affect the performance of the cleaning device [7]

Methods

Results

Conclusion