In the multi-tooth drum design of rice and wheat thresher, the gradient distribution of the gap between teeth is the key to improving the threshing rate and reducing grain damage. This gradient distribution is not set randomly, but is carefully designed according to the changes in threshing requirements during the entire process from rice and wheat entering the drum to being discharged, so that the gap at each stage can adapt to the corresponding threshing state.
In the area where the material just enters the drum, the gap between teeth is set relatively large. At this time, the rice and wheat straw is relatively complete, and the grains carried are mostly wrapped in the ear. The larger gap allows the straw to enter smoothly, reducing the initial congestion. At the same time, through the initial impact of the teeth, the grains that are easy to fall off are separated first, laying the foundation for subsequent deep threshing, avoiding straw accumulation due to too small a gap, affecting the overall threshing efficiency.
As the material moves to the middle of the drum, the gap between teeth gradually decreases. When entering this area, most of the grains that are easy to fall off have been separated, and the remaining grains are mostly tightly attached or hidden deep in the ear, requiring stronger threshing force. The reduced gap allows the teeth to come into closer contact with rice and wheat. Through squeezing and friction, the stubbornly attached grains are peeled off from the straw, thereby increasing the threshing rate and ensuring that as many grains as possible are separated.
In the exit area of the drum, the gap between the teeth will increase appropriately. After deep threshing in the middle, the remaining straw is relatively loose and there are few grains left. At this time, the larger gap can reduce the excessive effect of the teeth on the straw, prevent the separated grains from being squeezed and rubbed again at the exit and cause damage, and allow the straw to be discharged smoothly, reducing the entrainment of grains.
The gradient distribution of the gap between the teeth can also reduce grain damage by adjusting the changing rhythm of the threshing intensity. During the threshing process, the impact force on the grains is closely related to the gap between the teeth. The change of the gap from large to small and then to large makes the threshing intensity present a rhythm of first gentle, then enhanced, and finally relaxed, which not only ensures the separation of difficult-to-thresh grains, but also avoids the damage to the grains caused by continuous high-intensity action.
At the same time, this gradient distribution can make the material flow in the drum smoother. The gaps in different areas adapt to the state of the material at different threshing stages, allowing the straw and grains to move in an orderly manner along the predetermined path, reducing collision and extrusion between each other. The grains are separated in a smooth flow and will not be squeezed and damaged by the straw due to congestion, further ensuring the integrity of the grains.
In addition, the gradient distribution of the gap between teeth can also adapt to grains of different fullness. Full grains have a strong ability to resist damage and can withstand stronger threshing in areas with smaller gaps; while unfull grains can avoid excessive extrusion in time through flow during gap changes, ensuring separation while reducing damage. This adaptability allows the rice and wheat thresher to still take into account both the threshing rate and grain integrity when dealing with rice and wheat of uneven quality.
The gradient distribution of the gap between the teeth of the multi-toothed roller improves the threshing rate and reduces grain breakage by adapting to the needs of each stage of threshing, adjusting the threshing intensity rhythm, optimizing material flow and adapting to grain differences, thereby improving the overall efficiency of the rice and wheat thresher.
