可呼吸性個人粉塵採樣器之研發

Development of a Personal Respirable Dust Sampler

10mm 尼龍旋風器普遍使用於可呼吸性粉塵的採樣，然其微粒收集效率受粉塵負荷及粉塵靜電之影響十分明顯。本研究設計一新型旋風器，以解決粉塵負荷及粉塵靜電的問題。新型旋風器以導電的鋁合金製作,並加大內徑尺寸及出口管長以降低微粒累積於內壁的厚度，減少微粒負荷對收集效率的影響。實驗結果顯示氣動直徑為3.06μm 微粒，靜電量為4500電荷數目時，與Bolzmann 靜電平衡的微粒相較，鋁合金旋風器的微粒收集效率增加5.1% 。新型旋風器的微粒收集效率幾已不受粉塵靜電之影響，而其截取氣動直徑因粉塵負荷所造成的變化遠較10mm 尼龍旋風器減少很多。新型旋風器採樣流量在1.7 L/min 時，其收集效率曲線能符合新ACGIH 規範。

The 10mm nylon cyclone is commonly used as a respirable dust sampler. Effect of part icle mass loading and particle electrostatics on particle collection efficiency is still significant. A new cyclone has been designed and tested to solve the particle loading and electrostatics problems mentioned above. The new cyclone is made of conductive a luminum, and its inner diameter and outlet tube length are increased to reduce the thickness of particles accumulated at the inner wall and hence the effect of particle loading. The experimental results indicate that the collection efficiency of the new design is nearly unaffected by particle charge and has a significant reduction in the variation of cut-off diameter and particle collection efficiency curve induced by mass loading. For example, the collection efficiency increase 5.1% when the number of charge is 4500 for the 3.06μm particle. The collection efficiency of the new cyclone has been found to match the new ACGIH criteria for respirable dust sampling reasonably well at the flowrate of 1.7 L/min.