落地型斜氣簾式排氣櫃性能評估

Abstract

斜氣簾式排氣櫃在櫃底工作面上加上一道上吹二維氣流，並在左右側牆內安裝一片直立的長型導流板，配合狹縫形上吸式氣罩，使櫃內形成一道傾斜的空氣簾幕，配合上吹噴流吹氣速度、吸氣槽吸氣速度與其它參數，能有效將污染物控制在氣櫃內部。污染物洩漏率較傳統型排氣櫃大幅降低，且該氣櫃的能源消耗較傳統型排氣櫃可節省能源40%以上。 本研究為瞭解斜氣簾式的設計應用在落地型排氣櫃上之效能。依斜氣簾式氣櫃概念設計一台變風量落地型斜氣簾式氣櫃。使用面速度量測法量測不同高度下的櫃門開口面速度分佈情形，以瞭解抽氣量改變與面速度變化的關係。在prEN 14175-3：2003內部量測面追蹤氣體測試結果顯示，在櫃門開度H=50cm時，p1~p8八個區塊的平均洩漏率小於0.005 ppm，瞬間最大洩漏值為0.027 ppm，符合英國(Invent-UK 2004)中的”Good”等級。 本研究中使用自行設計的追蹤氣體釋放器搭配採樣探頭進行開口逸散模擬量測，在10cm至25cm的開口高度下，追蹤氣體SF6洩漏濃度皆能保持全程”零洩漏”(洩漏值小於0.005 ppm)。在H=30cm及35cm，僅出現瞬間峰值0.011 ppm及0.01 ppm，平均值仍小於0.005 ppm。35cm以下的櫃門操作高度其洩漏值表現如套用英國(Invent-UK 2004)的分類標準，都接近”Excellent”等級。櫃門開關動作洩漏測試中，當釋放器高度Hej=60cm，櫃門H開至100cm，其階段平均SF6洩漏濃度為0.093 ppm，瞬間峰值為0.28ppm。改變吹氣槽吹氣速度的櫃門開關測試結果Vb=1.7m/s，Cavg=0.056ppm；Vb=0.7m/s，Cavg= 0.115ppm；Vb=0.2m/s，Cavg=0.179ppm。當Vb越大，櫃門開關動作時的整體洩漏率越低。強健度測試結果中，吹氣速度Vb= 1.7 m/s 時的強健度干擾測試SF6洩漏平均濃度0.041 ppm亦優於Vb=0.7 m/s下的0.155 ppm。由以上數據顯示，此落地型斜氣簾式排氣櫃在20cm的設定操作高度下，能有效將污染物控制在櫃內。

The inclined air-curtain (IAC) fume hood employed in the present work was constructed with the cross-flow fan at the bottom, deflection plate along the side walls, and a suction slot at the top of the cabinet. The containment in the cabinet were controlled effectively by using the two-dimension blow velocity and suction velocity. A research of an IAC walk-in fume hood performance was operated in several methods. Face velocity was measured on sash opening plane to know the distribution and it’s average face velocity. Tracer-gas testing of the IAC walk-in hood was performed in two ways. One is in accordance with the methodology described in EN14175-3 Fume cupboards-Part 3：Type test methods. Tracer gas is 10%SF6 in nitrogen balance. Another one is self-developed method. Tracer gas is 5%SF6 in nitrogen balance and it is released by own designed ejector. The mean leakage SF6 concentration is less than 0.005 ppm by inner test method based on EN14175-3. The peak concentrations are 0.027 ppm. It is classified as “Good” grade in Invent UK 2004 Standard. The tracer gas concentrations are less than 0.005 ppm in 10cm、15cm、20cm and 25cm sash opening by self-develop method. In 30cm and 35cm test, the peak concentration are 0.011 ppm and 0.01 ppm. The average concentration of SF6 is 0.093ppm, peak concentration is 0.28ppm at Hej=60cm、H=20cm~100cm sash movement test. The average concentration is 0.041ppm, peak concentration is 0.108ppm at Hej=(74,40,60)cm、H=20cm robustness test. Both of results are met the limit values of professional association of the Germany chemical industry technical committee chemistry. When the blow jet velocity (Vb) decreased, the containment efficiency also reduced at sash movement test and robustness test. This result showed that an adequate blow jet velocity would provide a higher containment performance.