Drying Characteristics of a Single Grain of Wheat

Abstract

The authers constructed an apparatus for measuring the drying characteristics of a single grain of rough rice which was reported in the previous papar. The drying characteristics of a single grain of wheat at 10cm/s and 1cm/s air velocities was measured using the same apparatus but with a modified humidifier.
1. The temperature, the relative humidity and the air velocity were controlled within a range of (30-60) ±0.5°C, (40-80) ±1-2% R. H. (1-10) ±0.1cm/s, respectively.
2. The drying curves of wheat obtained were shown in Figs. 3 and 4. Both the constant rate period and the falling rate period were observed excepting the cases in which either the air temperature was 30°C or the relative humidity of the air was 80%.
3. The constant rate period was in the range of 5.5-22.4% d.b./h, except for 60°C, 0% R. H. 10cm/s air velocity (48.9% d. b./h). If the air temperature was the same, falling rate curves showed the same slope regardless of the humidity of the air.
4. At 30°C air temperature, there existed only the first falling rate period, but at air temperatures over 40°C, both the first and the second falling rate periods appeared.
5. The higher the temperature of the air, the influence of relative humidity upon the slope of falling rate curves was more pronounced, (Figs. 5 and 6)
6. The moisture content ratio was influenced both by the air temperature and the relative humidity, but the influence of relative humidity was little. (Figs. 7 and 8)
7. At a constant relative humidity, equilibrium moisture contents became almost the same in spite of differences in air temperature.
8. There was little influence observed of the air velocity around a single grain of wheat upon its drying characteristics.