Corrective Method of Apparent Density of Cereals in the Moisture Meter of Electrostatic Capacity Type

Abstract

Moisture content control is important in the processes of grain drying, processing and storage after harvesting of cereals such as rice, wheat and barley. These automatic systems require the automatic moisture meter which is able to measure non-destructively, continuously, speedy and accurately. We notice the electrostatic capacity method as fulfilling these requirements, but the largest defect in this method is that the measured value is affected by the apparent density. Therefore, when we measured the electrostatic capacity, we used two different high frequencies, and calculate the ratio of them. We named moisture index this Ratio R as a parameter. The effect of the appararent density of cereals became very small by using R and we have obtained a good correlation of R with the moisture. In this peper we describe that we introduced moisture index R from simple models and confirmed experimentally the effectiveness of adopting this index.