| Summary: | 碩士 === 國立勤益科技大學 === 冷凍空調系 === 105 === HEPA(High Efficiency Particulate Air Filter) are widely used in different class of clean room air conditioning in order to maintain room cleanliness demand. In this study, a test facility of HEPA total efficiency is setup with 610 × 610 mm square air duct by using DOP method to test HEPA filter efficiency and dust holding capacity. The filter material is glass fiber and classified to the European regulations H13 category. During testing, air velocity is set at 0.25, 0.4 m/s and the PAO aerosol is released from an aerosol generator by using Laskin nozzle following the European and American standers suggestion. The concentration of aerosol and penetration rate is measured and calculated by using light-scattering photometer. This study uses time and pressure drop about data record, analyzing effect on filtration efficiency and dust holding capacity of air velocity, concentration of PAO aerosol, filter thickness of material.
First, air velocity was 0.25, 0.4 m/s and PAO concentration of 25, 50 μg/L during testing. PAO concentration testing is the through the same HEPA filter specification and its efficiency varying with time, as a result the effect on efficiency of air velocity is stronger than PAO concentration. Secondly, this report explore the reproducibility with the same HEPA filter specification. In this study, air velocity was 0.25, 0.4 m/s and high concentration of 50 μg/L in appropriate conditions. Comparison with efficiency and dust holding capacity are three groups of experiment, this high test condition is used 0.4 m/s and 50 μg/L for filter thickness of material to simple observe. Finally, filter thickness of material was tested for 50, 69, 78, 117 mm during testing. The effect on filter thickness of material was explored the test time to change. If filter material thicker, the efficiency decreases slower. Because filter thickness of material was showed the protective ability of the stronger, it also longer service life of HEPA.
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