Development of air suction cleaning device of vertical conical peanut sheller for plot planting

Peanut shelling for scientific research and sample inspection presents the special characteristics: small amount, multiple varieties, treatments and batches. A separate shelling is required, where the shelled peanuts cannot be mixed. After shelling, the seeds are also required to be quickly cleaned. At present, manual operations are still used to shell and separate the peanuts in the absence of shelling and separating equipment, leading to the low efficiency and the problem of “mixing”. A kind of special peanut shelling equipped with the separating equipment is highly demanding in small scale to meet the above requirements. Compared with the commercial peanut shellers, the study on the special peanut sheller with a separating device is lacking, particularly for the peanut scientific research and sample inspection. In this study, the cross-flow air-suction separating was proposed to establish a three-channel air-suction cleaning scheme in a vertical peanut sheller, in order to improve the separation performance of special peanut sheller. Taking “four red” variety of peanuts as an example, the aerodynamic factor of material was proposed, according to the floating characteristic test, thereby to explore the relationship with the floating speed of material. According to the automatic sliding condition of materials after peanut shelling, three guide plates were designed in the collection bin, where the inclination angle of guide plates was set as 50°. The mechanics and kinematics equations were established for the cross-flow air-suction process after peanut shelling, using the aerodynamic factor of materials. The movement trajectories and laws of material components were established at the suction port of separation bin in the horizontal airflow, with emphasis on the criticality of cross-flow suction. The optimal condition was that the critical air velocity was 2 m/s, and the critical height of suction port was 100mm, where the adjustment range for the height of suction port was determined to be (100±40) mm, the width was 100 mm, and the height of separation bin was 160 mm. According to the critical air velocity and its adjustment, a single-intake small centrifugal fan was chosen with a radial straight blade impeller, where the fan speed was 1 200 r/min, and the flow rate was 6 m3/min. In the performance test, the results show that a stable working performance was achieved in the cross-flow three-channel air suction separating device, matching with the tapered drum shelling device in an integrated whole machine. The separating loss rate and impurity rate were related to the height of suction port. Specifically, the separating loss rate decreased, while, the impurity rate increased, as the height of suction port increased. When the speed was 1 200 r/min, and the feed rate was 15 kg/min, the comprehensive separating performance was the best, where the height of suction port was 80 mm, the loss rate was 2.01%, and the impurity rate was 0.98%, indicating that better performance than that of the industry standard. The finding can offer a certain reference for the further development of small-scale peanut shelling and separating equipment, particularly for the scientific research and insection on peanut products.