Abstract
1. Using the different shapes and structures of impellers, the extent of tea-leaf injuries made by the thrower while being conveyed was investigated chemically and physically. Tea-leaves were harvested in several seasons and at several stages of growth.
2. The rate of damages of leaves rose with the increase of throw speeds. The relation among the damage degree Y (%), the revolution number N (rpm) and the throw speed V (m/s) of impeller was shown by following formulas in the range of this experiment.
Y=4.3×10-7N2.64
Y′=8.1×10-3N2.64
The damage degree increased with the power of speeds which was between 2 and 3. Therefore lowspeeds were desirable for the economy of power and damage reduction. The increase of damage was within 3% at normal revolution speeds
3. Observing the relation between wings structure and tea-leaf damages, the presence of mat and nylon wire brushes in the first cut tea leaves, and of brushes in the third-cut ones, was very effective to reduce the damage. But wings shape and carring capacity per hour had little to do with it.
4. If the structure and use of thrower, handling of tea-leaves are proper the quality of products does not necessarily go down by conveying tea-leaves within normal throw speed. Threfore this thrower may be successfully employed as a carrying system of tea-leaves.
