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To improve the conveying efficiency and working stability of a screw conveyor, the feeding methods, running conditions and flow characteristics of materials were studied by theoretical analysis and experiments. The theoretical analysis results show that the screw conveyor runs more stably when the helix angle of the screw blade is equal to the moving helical angle. A new spring-finger was designed by us and was used in the experiment. The experimental results show prove that the spring-finger feeder can help homogeneously and continuously to feed the screw conveyor and to improve the working stability of the screw conveyor. The movement state of materials along a pitch was videotaped by a high-speed camera with different filling rates and rotation speeds. The photographs and videos reveal that the characteristics of the materials and rotational speed affect the conveying performance and provide the basis for selecting the best operating parameters for screw conveyors.

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Various problems are encountered during the screw feeding process of chopped cornstalk. Therefore, it is important to deeply analyze and understand the relationship between conditions and productivity of screw conveyors. This study reveals the influence of air velocity, pitch, rotational speed, and feeding rate on productivity, power consumption, specific power consumption and pressure of material for a coupled screwpneumatic conveyor. Through a theoretical analysis, a mathematical model is established that simultaneously considers the compression characteristics of the material, material pressure from the change in pitch and centrifugal force of the screw axis, productivity of the coupled screw-pneumatic conveyor, power consumption and specific power consumption. Then, experiments are conducted to investigate the influence of the structural and working parameters of the conveyor on its performance. Finally, the correctness of the theoretical calculation is verified through a comparison with experimental results. The results of the theoretical analysis are in good agreement with the experimental results, and the relative deviations fall within 10%, 13%, 14% and 11% for the productivity, energy consumption, specific consumption and material pressure of the conveyor, respectively. With increasing airflow speed, pitch, rotational speed and feeding volume, the power consumption increases, and the other parameters have their own trends.