超細粒徑微粒濃縮器（UFPC）是目前唯一可同時濃縮細粒徑與超細粒徑微粒之濃縮器，但原始系統之操作仍有許多不方便之處，例如人力耗費、溫度控制不易、濃縮效果不穩定、系統容易損害等。為了改進這些使用上的缺失，本研究已完成此微粒濃縮器操作介面之改善與自動化，包括：飽和蒸汽單元、乾燥系統及冷卻單元操作介面之改善；完成自動控制軟硬體之設計；系統濃縮效率之測試。目前系統可由電腦即時監測並紀錄系統溫濕度、流量、濃度等參數，並由電腦控制飽和蒸汽箱水溫與冷卻循環水之流量。而性能測試之結果發現溫度之控制相當穩定，但濃縮倍率之範圍約為5至16倍，與理論值22倍有所出入，其原因推測可能與空氣中的含水量有某種程度之相關。 本研究所改善完成之UFPC系統已具備長時間無人操作之能力，除了使用者在操作時更加方便之外，也有助於未來從事最佳操作參數探尋與可調整型濃縮倍率等之研究。 The Ultrafine Particle Concentrator (UFPC) developed by Dr. Sioutas at University of South California is the only device in current market that can concentrate both fine and ultrafine particles at the same time. Despite of its abilities to enrich particle concentrations, the original design of the UFPC, however, has many problems: The system requires many attentions because it was built around parts and modules that need to operate manually; The use of salt and ice to keep frozen temperature in the cooler once caused a corrosive tube that finally destroyed a pump and several valves; The UFPC can’t be continuously operated, because ice in the cooling tank must be changed after 3 or 4 hours operation. The purpose of this study was to maximize the duration of each operation and to minimize the use of manpower while using the UFPC in studies that requires high concentration ambient particles. To achieve that, several new modules were built. A new saturator and a new cooler both based on close-loop-circulation design were constructed to extent the operation; A longer diffusion dryer was used to eliminate the excess water in the minor flow air; Temperature, relative humidity, and flow sensors were added to monitor conditions of the system; A Windows based software was designed to collect information from sensors and to control temperatures at desired levels in the saturator and the cooler. Several tests were conducted to verify the performances of the new of the UFPC. The results showed that the new system was able to continuously operate for hours. The only thing that stops the UFPC for a brief moment is to replace the drying column. The enrichment factors (EFs) tested with artificial and ambient particles were varied from 5 to 16 that theoretically should be 22. The collected data indicated that the EFs were highly correlated with relative humidity in the incoming air (r=0.8 to 0.9). The amounts of water in the air may have strong influences in the growth of particles that later decides whether the particle can be concentrated or not. Before other hard evidences can be found, this explanation, however, remains a guess.
