| With more and more share the bulk cargo occupying in the world's whole freight volume, the conveying efficiency receives more and more attention. While among the whole bulk conveying process, how to effectively and conveniently put the bulk into the conveying process is one of the most important key problems. The article gives a good solution by providing with a brand-new equipment—Screw-gas Bulk Sucking and Taking Equipment, which applies both the theory of vertical screw conveyor and the theory of pneumatic handling.Screw-gas Bulk Sucking and Taking Equipment constitutes of 3 parts. Respectively from bottom to above they are:Centrifugal force Separating Part, Screw Lifting Part and Pneumatic Conveying Part. Granular material is drawn into the equipment in the form of gas-solid two-phase flow by the Atmospheric pressure, and then helically rises in the Centrifugal Force Separating Part which is an inverted cone. The material would be separated from the two-phase flow by the effect of centrifugal force and then be lifted in the Screw Lifting Part. The gas flow with the very little remained material would be drawn into the blower. By thus Screw-gas Bulk Sucking and Taking Equipment could take the material and put it to the next conveying process conveniently and efficiently with the superiorities of low clearing-up, little dust removal, simple construction and convenient maintenance.The following results have been achieved:1. The feasibility of this Screw-gas Bulk Sucking and Taking Equipment was demonstrated; the test bed for this device has been established and a lot of experimental researches based on it were conducted. Tests proved that this feeding device could be a good choice, which could realize self-feeding and separating gas-solid two-phase with high effectiveness and efficiency.2.The mathematical model of the critical separating-particle size in the flow was established; and based on it, how the critical particle size could be affected by the size of the device, the spiral speed, the air-flow entering speed and the material density was analyzed. Thus provides a theoretical base for the design work;3.The mathematical model of the separating interface of gas-solid two-phase flow was established and the flowing movements of the material and the gas were analyzed, determining the equation of material motion and gas speed equation;4. The critical gas entering speed was determined by giving a certain range, enabling it to suck the material with enough speed, and also to ensure that the material be separated from the gas-solid two-phase flow;5.The terminal velocity of the material flow separated from the gas-solid two-phase was determined, which could determine the material to be captured by screw leaves or taken away by the gas. Particles under the centrifugal force will overcome the resistance, and thrown out, flowing with the terminal velocity relative to the movement;6. A comprehensive analysis of all the possible variables in the separation process was finished, using dimensional analysis method to achieve the test model criteria, which provides the basis for the accurate prediction of this Screw-gas Bulk Sucking and Taking Equipment separation performance.Screw-gas Bulk Sucking and Taking Equipment own the advancement of self-feeding, high efficiency, low clearance and many other advantages. By applying this device, the problems of separating in pneumatic conveying, self-feeding in bulk material handling, and clearance issues could all be resolved, which provides conditions for the possible new effective plans of the bulk material handling processes, and it could be a new trend for the unloading bulk technology development.
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