マメ科牧草の圧縮・成形性 (第1報)

ダイ連続押出し方式の基礎実験

抄録

Wafers of leguminous hay was made by continuous compressing and extrusing with a pair of dies and a piston, and the characteristics of wafers such as compressive force, change of density, falling shock durability and tensile strength were investigated.
The results were as follows:
1. The apparatus was able to make wafers when the moisture content ranges of alfalfa and ladinoclover were about 13-55% and 17-35%, respectively. The collapse of these fibers grew when the moisture contents reduced and compressive stresses of alfalfa and ladinoclover reached approximately 830 and 500kg/cm², respectively.
2. The maximum compressive force increased quickly as moisture contents decreased. It reduced when the hay was rewetted by water spraying after ground drying, however, the value was larger than that of ground dried hay if the moisture content was the same. In general, the maximum compressive force of alfalfa was larger than that of ladinoclover.
3. The equation expressing the selation between the compressive force and stroke curves was
P=ae^bL
where P=compressive force
L=piston stroke
a, b=constant
and the compressive forces increased with the increase of compressive velocities, especially with dried hay.
4. The falling shock durability of wafers which had been dried to 12% moisture contents, generally, was smaller than that of before drying, and the durability became maximum when the forming moistures of the hay were each about 23-25%.
5. The tensile strength of wafers increased quickly as moisture contents decreased, and had not a direct relation with tensile strength of hay stems or falling durability of the wafer. Therefore, it was considered that the tensile strength of wafer was not a practical indicator for the durability of wafer.
6. In general, the densities of wetted or perfectly dried wafers and its magnifications increased quickly as the moisture contents of hay decreased. Therefore, they were not practical indications of durability of wafers just as the tensile strength was not.
The magnifications of density of alfalfa and ladinoclover were about 25-45 and 18-45, respectively, and generally, the former was larger than the latter, and they increased with the decrease of moisture contents.
7. The useful wafer of leguminous hay could be easily formed at normal temperature by use of a die, 100mm long, 50mm wide and 12mm in thicknesses, and the most desirable moisture content was approximately 23-25%.