风筛式清选装置非均布气流清选原理与试验

Theory and Experiment on Non-uniform Air-flow Cleaning of Air-screen Cleaning Unit

脱出物从横置的轴流式脱粒装置下落到纵置的清选筛上时,在筛面入口段堆积成堆影响清选。提出了非均布气流清选原理,设计了圆锥形离心风扇以产生非均匀气流。理论分析和试验验证表明:由圆锥形离心风扇大、小端的直径差形成的非均布气流产生了风压差,使振动筛前部出现了较大的横向风速(最高处2.6 m/s),将下落中的脱出物向另一端吹送,使脱出物在振动筛面的初始分布明显改观,从而改善了横置轴流式全喂入联合收获机的清选性能。

The grain dropped to longitudinal cleaning sieve from threshing unit mound in the right corner of the screen deck will block cleaning. The theory of non-uniform air-flow cleaning was put forward and the conical centrifugal fan, resource of non-uniform air-flow was designed. Theoretical analysis and experimental verification show that, as the diameter difference between the small-end and big-end of conical centrifugal fan, the wind pressure difference of non-uniform air-flow forms, which results in high transversal wind velocity in the front of vibrating screen （the highest velocity is 2.6 m/s）. The wind pressure difference puffs falling grain to the other side, which changes initial distribution apparently and improves cleaning quality of transversal axis-flow feed combine.