In view of the high requirement of solid phase quantification for pneumatic conveying in some parts of industrial & agricultural production,a common positive pressure Laval nozzle bin pneumatic conveying system and back feed automatic control system were established.Experiments were carried out in this pneumatic conveying system by transporting bechilite powder.The trend of solid conveying capacity during the conveying process is obtained according to the results of precise weighing sensor test and ultrasonic testing method.Through the comparison of solid flow before and after automatic control,it can be seen that the stable conveying time increases 16～18 s,meanwhile the fluctuation of solid conveying capacity is less than ±8％ in condition of automatic control status.The results show that the automatic control scheme improves the stability of solid flow greatly.%针对目前工农业生产中部分工艺中对气力输送固相定量性要求较高的现状,建立常用的正压拉法尔管式仓泵气力输送系统,并建立后反馈自动控制系统.以硼钙石粉体为输送物料,分别采用精密称重传感器测试及超声测试方法研究输送过程中固体流量的变化规律.通过实验对比自动控制前后的固体输送能力的大小及稳定性发现,固体输送能力稳定输送时间段增加了16～18 s,自动控制后稳定段固体输送能力波动低于±8％,表明启动自动控制方案能更好地提高固体输送的稳定性.
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