Design, Simulation and Experimentation of an Axial Flow Sunflower-Threshing Machine with an Attached Screw Conveyor

Abstract

Sunflower threshing is one of the most interesting field processes for making the sunflower ready for seed handling, drying, cleaning and oil extraction. One of the biggest problems observed during the sunflower threshing process is the accumulation of threshed crop on the first third of the threshing roller and passing off some unthreshed parts of sunflower heads. To solve the aforementioned problem and optimize the efficiency of the sunflower threshing process, this research was focused on devising and testing a sunflower threshing machine with a close threshing box system equipped with a screw conveyor that evenly distributed the feedstock of sunflower heads on the entire length of the threshing roller. The machine was tested to assess the seed damage rate, unthreshed seed percentage, threshing efficiency, machine productivity, power requirements and specific energy consumption. The evaluation was done under different roller rotational speeds (150, 200, 250 and 300 rpm) and feeding rates (600, 700, 800 and 900 kg/h). The obtained results revealed that the threshing evaluation parameters were affected significantly by the roller rotational speed and feeding rate. The threshing efficiency was observed to rise with the rise in the roller rotational speed, and it also rose with the increasing feed rate up to 800 kg/h and then started to descend. The unthreshed seed percentage decreased with the increase in the roller rotational speed for all feed rates, and it decreased with the increasing feed rate up to 800 kg/h and then started to increase at the higher feed rates. The damaged seed percentage, power requirement and machine productivity increased with the increase of the roller speed and feed rate. The Buckingham π theorem was followed to find an equation to predict the threshing efficiency, resulting in an equation with an R2 value of 0.9309. With elimination of the blockage problem and better threshing efficiency, this machine could be a good choice for small- to medium-sized sunflower farms.

Enhancing the Performance of Sunflower Threshing Machines through Innovative Enhancements

“…Figures 9 and 10 exhibit a consistent trend across all rotor types, whereby the percentage of unthreshed seeds decreased with increasing rotor rotational speed and decreasing concave clearance, aligning with the findings of [30]. Markedly, the angled rasp bar rotor consistently exhibited a lower percentage of unthreshed seeds compared to the other two rotor types across all operational conditions.…”

Contributions to the Mathematical Modeling of the Threshing and Separation Process in An Axial Flow Combine

“…Having the values for S n (x), S l (x) and S s (x), from Relation (11), the evacuation losses p ev can easily be found:…”

“…In addition to the natural and crop conditions, the quality and quantity of harvested seeds, the development of the working process of a threshing machine is also influenced by the physical-mechanical properties, including seeds' moisture, forward speed of the harvesting machine, material flow rate (entering the threshing machine), rotor speed, reel height (for the cutting stage), speed of rotation of the threshing machine, concave clearance, type of threshing machine, angle of inclination of sieves, frequency of sieves, air speed (for separation stage), conveyor screw rotational speed and conveyor clearance (for conveying stage) [11][12][13][14][15][16][17].…”

Study on the Influence of Different Factors on Pneumatic Conveying in Horizontal Pipe

“…Traditional large-scale breeding enterprises commonly used particle feedstuff transportation mode with a stopper conveyor and screw conveyor [7][8][9]; although they can achieve sealed transportation, they cause component wear, particle breakage, and other shortcomings in the conveying process, which increases the cost in the conveying process and is not conducive to the long-term development of large breeding enterprises, so these devices are gradually eliminated. Compared with the traditional mechanical transportation mode, the pneumatic conveying device has the advantages of simple structure, convenient operation, and high conveying efficiency.…”