Search

The study addresses the development and substantiation of parameters for the hopper that is installed in the technological process for producing concentrated bulk feeds. The structures of hoppers, the ways of improving productivity and the quality of their operation were analyzed and the prospects for the development of this direction were determined. The effectiveness of dosing was enhanced by the modernization of the sieve hopper with a rarefied discharge of dosed material due to the use of the openings in the form of a five-petal epicycloid. To determine the rational design and kinematic parameters of the modernized sieve hopper, mathematical modeling of the movement of bulk medium was carried out, conditions of the process were selected and final mathematical expressions were found. In addition to the parameters of the moving hopper in expressions and during the experiments, the properties of bulk feeds were explored. The ranges of variation in the sizes of the holes of the bottom and upper sieves were determined, the amplitude and frequency of their oscillations, which are the important parameters of the process of dosing bulk feed on the proposed hopper. The modeling results were proved by the conducted experimental research. The dependences of the performance of a sieve hopper on its design and kinematic parameters in its basic and upgraded versions were experimentally established. The adequacy of the developed modeling was proved by admissible discrepancy of the results with the experimental results. Using these dependences on the condition of maximum effectiveness of dosing, the ranges of variation in the performance of the upgraded hopper, which amounted to 0.75…2.6t/h were determined. It was established that the use of sieves with activators enhances the performance of the hopper by 15...44.4%. The adequacy of the developed mathematical modeling was proved by admissible discrepancy of the results and experiments, which did not exceed 5%. The result of our research is the devised procedure for studying the sieve-type hoppers, which implies a possibility to explore the impact of shapes and sizes of openings on the effectiveness of dosing bulk feeds

The productivity of most grain cleaning machines seems to be directly related to the efficiency of vertical pneumatic separation ducts. Nevertheless, improvement is accompanied by an increase in the load of the vertical duct, the design of which is limited by the width of the grain cleaning machines. This requires an increase in the thickness of the layer of grain mixture that enters the working area of the duct, which significantly worsens the conditions of separation of its components under the action of airflow. Particles of light impurities are unable to separate due to their retention by the grain medium. This reduces the quality of cleaning and requires appropriate scientific and technical solutions. The application of preliminary stratification of the granular mixture while increasing the concentration of light impurities in the top layer of the mixture seems to be a prospective method. The positive effect of the previous stratification on the intensity of redistribution of light impurity particles in the working zone has been theoretically considered and experimentally confirmed. Mathematical models were obtained to determine the trajectory of discussed particles, taking into account the previous stratification of mixtures, and the corresponding dependences were established. The influence of the initial coordination of the introduction of the particles of lightweight impurities, their sizes and densities, and technological and structural parameters of operation of the pneumatic separation duct were taken into account in the studies. The intensification of the process of cleaning grain from lightweight impurities in the working zones of pneumatic separation ducts of grain cleaning machines is theoretically substantiated.