• 설비공학논문집
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• 제3권3호
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• pp.176-185
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• 1991

Pressure drop and flow characteristics through a filter medium have been investigated numerically. A basic model similar to the filter employed in a hard disk drive was established so that the inflow velocity was 0.1 m/s and the box size was $40mm{\times}50mm{\times}30mm$. The filter medium specifications were 0.38mm of thickness, $1{\mu}m$ of fiber diameter, 0.05 of packing density. And the filter medium was pleated by 10 within the filter box. Twenty-one sets of calculation were performed with different inlet velocities, pleated numbers, and packing densities from the basic model. As the result, it was found that the velocity after filter medium had maximum value at the rear of the upstream pleated line, but had minimum value at the rear of the downstream pleated line. This made the velocity distribution have sinusoidal form immediately after the filter medium. As the inlet velocity increased, the pressure drop increased linearly. But as the packing density increased the pressure drop increased quadratically.

• 설비공학논문집
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• 제16권1호
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• pp.1-7
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• 2004

This study has been numerically conducted to investigate the removal efficiency of Volatile Organic Compound (VOC) for different photocatalytic honeycomb filters. Recently, the photocatalysis is being applied to air-cleaner, air-conditioner and vacuum-cleaner with the capability of air-purification, sterilization and antibiosis. However, photocatalysis is less efficient than other methods for removing VOC except in the case of low concentration. So far most of studies have focused on an improvement of the photocatalytic materials, but this study have placed emphasis on the improvements of shape of photocatalytic honeycomb filter. UV irradiation, concentration profile and pressure drop have been investigated for different cross sections of filters and for different filter lengths. Light intensity is dropped sharply with increasing distance from the UV-lamp, and becomes very low in the middle of the filters. Since photocatalytic reaction rate is a function of light intensity, VOC concentration gradient might be small in the middle of long filters. Thus, most of reaction have risen within only three times of dimensionless axial distance. These results can be used effectively for the design of advanced photocatalytic honeycomb filters.

• 한국물환경학회지
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• 제22권1호
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• pp.45-50
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• 2006

This study was performed to evaluate the air lift reactors (ALR) by variations of HRT and recycling rate. Air lift reactor was composed of bioreactor and clarifier above it. To remove organic matters and nitrogen through the formation of microbic film and filtration, bio-filter reactors were filled with clay, glass, bead, waste plastic, respectively. Influent wastewater was fed to biofilter reactor, and effluent wastewater from bio-filter reactor was injected ALR again, instead of adding external carbon source. Effluent BOD concentration was satisfied with lower than 10 mg/L in recycling rate 100% regardless of the variation of HRT and the kinds of media materials. In HRT 4 hr, recycling rate 100%, BOD removal efficiency rate was from about 85 to 90%, COD removal efficiency rate was higher than 90%. Effluent TN concentration was satisfied with less than 20 mg/L, if HRT was maintained by over than 6 hr regardless of recycling rate and media materials. Over than HRT was 4 hr, microbes concentration in air lift reactor was maintained over than 2,500 mg/L constantly, not sensitive to environmental condition, and organic removal was effective as it was higher.

• Elastomers and Composites
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• 제49권1호
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• pp.1-12
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• 2014

전투기 연료필터의 막힘은 조종사 생명과 전투기의 손실에 큰 영향을 줄 수 있다. 따라서 결함 연구는 사고를 미연에 방지하는데 매우 중요하다. 전투기 연료필터는 제트 연료에 포함된 다양한 불순물을 여과하는 중요한 기능을 수행한다. 연료 필터는 시간당 1,330 파운드의 유속으로 공급되는 제트 연료에 함유된 10 ${\mu}m$ 크기 이하의 불순물을 여과한다. 필터는 운영시간 기준 500 시간마다 교체되어야 한다. 그러나 500 시간이 도달하기 훨씬 전에 연료 필터의 막힘 현상으로 경고등이 켜지고 있다. 이와 같은 유사한 결함이 최근에 반복적으로 발생하고 있다. 그러므로, 이 연구에서는 전투기의 연료 필터 막힘에 대한 원인을 FT-IR microcopy, FE-SEM/EDS, 총 황함량 분석기와 같은 다양한 분석기술을 이용하여 조사하였다. 결론적으로, 연료 필터를 막히게 한 물질은 내부 연료 탱크용 실란트에서 기인한 가류 촉진제로 확인되었다. 그리고 연료 탱크내에서 가류 촉진제 블루밍 현상에 의해 연료필터를 막히게 하는 물질의 형성에 대한 메커니즘을 제시하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.154-157
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• 2001

The effects of pleating parameters on the performance of cylindrical cartridge air filters was experimentally studied. The tested filters are 150 mm in outer diameter and 700 mm in length. As the pleat count increases, the pressure drop across a cartridge filter is decreased for a constant pleat depth and flow rate. This is due to the increased filtration area which brings out less pressure loss of the filter. However, in the case of the filters having the pleat depth of 40 mm, the inner diameter of the cartridges is so small that the pressure loss is greatly increased.

• 펄프종이기술
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• 제41권4호
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• pp.58-64
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• 2009

This study was carried out to prepare high porosity pulp for oil and air filter media from commercial grade NBKP with 6 - 20% NaOH treatment. The fiber width of NBKP remarkably decreased by NaOH pretreatment. The air permeability of the test sheet prepared from alkali-pretreated NBKP increased with increasing NaOH concentration up to 15%. The burst factor was greatly decreased by alkali pretreatment. By 15 - 20% NaOH pretreatment of NBKP, it could be possible to prepare a high porosity pulp. It seems that the high porosity of the pulp was due to a strong swelling and a great change of the cellulose crystalline lattice from cellulose I to cellulose II with NaOH treatment of NBKP. The study suggested that alkali- pretreated NBKP could be used for manufacturing oil and air filter media.

• 한국세라믹학회지
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• 제50권4호
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• pp.245-250
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• 2013

A hydroxyapatite air filter was made with hydroxyapatite powder, water and chitosan solution. The structures of the sintered HAp samples were determined by MP-XRD. Hydroxyapatite has antibacteria properties against Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. The bacteria removal rate was 99.9%. In the case of Pseudomonas aeruginosa, Colon bacterium and Listeria monocytogenes, the hydroxyapatite air filters had a clear zone which confirmed antibacteria properties. Using the microscopy, we observed that the HAp powder absorbed E. coli bacteria.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.1131-1136
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• 2006

In this study, an experimental and numerical analysis on the flow characteristics of heating and cooling unit installed within ceiling with functional modules was carried out. And the flow characteristics of the heating and cooling unit was investigated with the main parameters such as each filter and inside structure. The experimental results show the possibility of medium filter application. And the numerical results show that the effect of improved inside structure of heating-cooling and air-conditioning unit on flow distribution.

• Composites Research
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• 제35권3호
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• pp.216-221
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• 2022

Recently, the worldwide demand for disposable masks has increased due to COVID-19 infections and severe air pollution. Personal masks should reduce breathe resistance while maintaining filtering performance. In this study, a solution blowing process is used to produce composite nanofiber filters to co-spin two polymers at once. The manufacture process of the various fiber diameter filter was designed, and the filtration performance and differential pressure of the prepared filter was investigated. Poly vinylidene fluoride-hexafluoropropylene (PVDF-HFP) and Polylactic acid (PLA) fibers were chosen to be entangled together in a layer with a diameter of 1.05 ㎛ and 0.33 ㎛. Composite nanofilters showed up to 87% filtration efficiency and 32 Pa differential pressure.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.567-568
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• 2021

본 논문에서는 UV-A와 UV-C를 포함하는 복합 파장의 LED 모듈을 적용한 캐빈 필터를 설계 및 제작하고 성능를 시험하였다. 제작한 캐빈 필터의 세균 및 공팜이 살균 시험에서 살균 능력을 확인하였고 유기화합물 분해 시험에서는 특수 챔버를 제작하여 유기물 분해 능력을 검증하였다. 광촉매로 콜케이트를 사용하는 것이 매탈매쉬를 사용하는 것보다 우수한 성능을 확인하였다. 본 연구를 통해서 제작한 캐빈 필터의 살균 및 공기 정화 능력을 실제와 유사한 환경 시험을 통해서 확인하였다.