抄録
The many characteristics such as extrusion force, maximum compression force Pmax, wafer density ρ, tensile strength T and durabilities I of rice straw wafer were experimented by use of a wafering hydraulic device of low speed extruding piston method with various straw moisture content, temperature and molasses content. The results obtained were as follows:
1. The relation of extruding force during compression vs. compression distance was found to be an approximate linear line as plotted on the semilog. graph, and the equation of which is
P=aebl
Where
P: extruding force (ton)
l: compression distance (mm)
a, b: a constant
2. In case of rice straw, the optimum temperature for wafering was about 25°C unlike other grass hay. The extrusion of wafer was found to be difficult at lower temperatures, while the waferability and durabilities were decreased at higher temperatures.
3. The ρ and T values of wafer could be taken as a good index of durability.
4. When comparing the straw wafer immediately after being formed with the one dried up to 12% m. c., the ρ value of the latter was slightly lower than that of the former, while the other durability indexes were found to be higher in the latter.
5. In case of rice straw, the optimum moisture content for wafering was about 20% m. c. like other grass hay.
6. The Pmax value and durability indexes were increased with the reduction of compressive speed or the increase of die length.
7. The waferability and durabilities of straw wafer were increased by rehydration unlike other grass hay.
8. In this experimental condition, the fall-shock durability index If after 15 falls was found to correspond approximately with the ASAE durability index IA, while the If value after 50 falls was considerablely smaller than IA.
Generally the ASAE durability method was undesirable for wide range indication of the durability of wafer.
9. Although it was impossible in some conditions to form straw wafer without molasses, it could be made possible by adding liquid molasses to it, and the Pmax value was found to reduce clearly while the durabilities were increased effectively.
It seemed as if there was an optimum mixing rate of molasses under 5-7% except 0%, but at the higher mixing rate, the durabilities were found to decrease and the wafer formation became gradually impossible.
