Measuring pressures in a slender cylindrical silo for storing maize. Filling, static state and discharge with different material flow rates and comparison with Eurocode 1 part 4

• We report the results of studies conducted using maize in a silo test station.
• Instrumentation consisted of load cells.
• Static and dynamic pressures were studied.
• We also studied the influence of the discharge flow rate (kg/s) on pressures.

In this paper, we report the results for pressures in full-size silos obtained from assays performed on a test station. This basically consisted of a mid-scale cylindrical silo equipped with load cells, with which it was possible to obtain most of the parameters used in the various theoretical calculation models and in existing regulations.Three different types of assay were conducted by varying the mode of silo discharge. In the first kind of assay, the silo was completely emptied following a period during which the stored material remained static. In the second type, a small amount of material was unloaded before interrupting the discharge, and in the third type, discharge was effected in several stages. We also studied the influence of variations in pressure on discharge speed.This study shows that variation in the discharge flow rate is not associated with a further increase in pressures and that the state of overpressure attained during discharge is essentially due to compaction or an increase in the specific weight of the material in given areas of the silo. We also observed that the discharge of a small amount of material caused a variation in pressures of the same magnitude as a complete discharge, and that previous pressure levels were not recovered once a partial discharge had been halted. The results of this study are compared with the Eurocode 1, part 4; in all cases, the values obtained were lower than those proposed in the Eurocode.

In this article, we report a study of pressures during silo loading and discharge using Maize as the stored material. We also studied the influence of the discharge flow rate (kg/s) on pressures. The results obtained were compared with Eurocode 1, Part 4.Figure optionsDownload as PowerPoint slide