关键词: 蒸发皿蒸发量, 蒸发皿蒸发量, 时空演变, 气象因子, 相对权重

Abstract: Tea dust, a production waste, can influence tea quality and be harmful to workers’health. It is necessary to analyze the concentration and particle size (φ) composition of tea dust in refined factory, thus to provide relative theories and technical approaches for tea dust control. The experiments were designed as: (1) setting 2 distance levels of around and 1.2 m away from the machines; (2) time setting (4 h and 8 h after working); (3) on-line detection and collection tea dust from 5 processes in black tea making. The results showed that the maximum dust concentration appeared in the vicinity of the screening machine (8 h, φ≤2.5 μm), up to 65.321 mg/m3. The dust density (φ ≤2.5 μm) of 1.2 m away from the machine was also high, which was 47.354 mg/m3 (4 h) and 44.987 mg/m3 (8 h), respectively. When the particle size was from 2.5 to 10 μm, the up-lifting screening machine produced dust most, the figure was 29.667 mg/m3 (4 h) and 26.919 mg/m3 (8 h), respectively. From the perspective of distance, there was more dust at 1.2 m away from the shaking sieve machine and winnowing machine, however it was on the contrary at the screening machine. The dust density from the different distances of the tight door machine was similar. With the special emphasis on respirable dust, we found that 82.1% of the dust was respirable at 1.2 m away from the winnowing machine. The dust density data (φ ≤10 μm) implied that closer distance was polluted more severely than 1.2 m away with the record of 59.7% (φ ≤2.5 μm) and 67.8% (2.5 μm＜φ ≤10 μm), respectively, but this was not applied to the tight door machine. In conclusion, the physical properties of tea dust vary with different technique processes, and the differences of the physical properties are directly related with mechanical performance of the machine, process parameters and space layout.