Studies on the Drying Method of High Moist Naked Barley with Multi Layer Passing Type Dryer

Independent Utilization of Multi Layer Passing Type Dryer

Abstract

To clarify the adaptability and the utility of the multi layer passing type dryer for naked barley, the processing efficiency of drying and pearling aptitude were investigated in different periods of harvest (moisture contents of grain) and forcedair temperatures.
Examination, of which tested grains were harvested by head feeding type combine, was practiced with a miniature dryer (Fig. 1) under the constant air flow rate of 0.10m³/s·100kg.
1) Periods of harvest and properties of naked barley
This experimentation was practiced in May 1979, and the month was unusually favored by fine weather, so that the drying rate of the standing naked barley was got to 5-6%/day (Table 1).
As the period of harvest was earlier, the containing rate of the unhulled grain increased the apparent density decreased (Fig. 2).
The higher was the moisture content of grain, the remarkably larger was the volume contraction with drying. The contraction ratio came up to about 60% in case of about 40% moisture content of grain, and about 75% in case of about 30% m. c. (Fig. 2).
2) Drying efficiency
We intended to have 3-4 layers of piled grain. But in case that the high moist grain was piled, the moisture absorption had occurred in the top layer under the condition of air flow rate 0.1m³/s·100kg (Fig. 3).
The higher was the moisture content of grain and the forced-air temperature, the more decreased the allowable number of layers of piled grain (Fig. 4).
In case that the air flow rate was 0.1m³/s·100kg, the processing efficiency of drying remarkably decreased with the initial moisture content of over 20-25% (Fig. 5). In case of the high moist grain, the processing efficiency of drying was slightly influenced by high forced-air temperature (Fig. 5).
3) Dignity and pearling aptitude
(1) Period of harvest, forced-air temperature and dignity-pearling aptitude
As the period of harvest was earlier, whiteness and powdery of grain increased and dignity deteriorated. Also lowering in the yield of pearled grainn and increasing in the rate of small pearled grain were remarkably recognized (Table 3). The unhulled grain was generally good for the dignity and pearling aptitude. But it had high hardness and needed long pearling time (Fig. 8, Table 4). As the period of harvest was earlier, the containing rate of unhulled grain increased, therefore it caused the irregularities in size and in colour of pearl barley. From the results mentioned above, in order to hold quality, the harvesting with combine should be practiced for naked barley under the moisture content of grain of 30%.
Forced-air temperature did not so influenced the dignity and pearling aptitude, except that the small pearled grain increases in the case of 75°C But forced-air temperature sensitively affected on the germination ratio. The germination extremely deteriorated in case of 75°C (Table 3).
(2) Harvesting systems and dignity-pearling aptitude
The binder-harvest system was particularly superior to the combine-harvest system on the dignity and pearling aptitude of naked barley, and the deterioration of dignity and pearling aptitude was scarcely recognized even in early harvesting (Table 5). From this result, it was considered that ear cutting-predrying-harvest system (tentative name), which was shown by the following working series, reaping-ear cutting→predrying-heating→threshing→final drying, would be effective.