• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.867-872
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• 2009

In centrifugal oil filters particles are forced to move toward the filter casing wall by centrifugal force in the rotating oil flow and the particles are trapped and removed on the filter paper installed at the wall. In the present study, flow field of oil and particle motion in a centrifugal oil filter has been numerically calculated in order to estimate the filtering efficiency for various operating conditions. Fluent code was used for the numerical calculations. Uncoupling the oil flow and the particle motion and the use of particle tracking trajectory enabled the estimation of filtering efficiency for various particle sizes, particle density and the filter rotational speed. Higher filtering efficiency was observed for heavier and larger particles as well as higher filter rotational speed. For the typical case of the particle density of $6000kg/m^3$ and the particle size of $10{\mu}m$ at 3500 RPM, the calculated filtering efficiency per passage was 0.31.

• 한국염색가공학회지
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• 제34권1호
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• pp.20-26
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• 2022

Centrifugal spinning is an emerging technique for fabricating micro-to-nano-fibers in recent years. To obtain fibers with the desired size and morphology, it is necessary to configure and optimize the parameters used in centrifugal spinning. In this study, it was controlled by changing the solution's concentration (7.5, 10, and 12.5 wt.%) and disk's rotational velocity (6,000, 8,000, and 10,000 rpm) to prepare centrifugal spun nano-filter. The morphological property, air permeability, and dust collection efficiency of the PVA/PP bi-layer nanoweb prepared by centrifugal spun PVA on the PP micron nonwoven substrate are studied using a field emission scanning electron microscope, an air permeability tester, and a filter tester equipment, and the analysis results indicate that it is suitable as a nano-filter when the concentration of PVA solution is 10 wt.% and the rotational velocity of the disk is 8,000 rpm. The resultant reduced diameter and uniform fibers also proved that an excellent dust collection efficiency filter could be made.

• 한국대기환경학회지
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• 제20권6호
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• pp.739-748
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• 2004

A hybrid dust-collector combining a fabric filter with centrifugal force was developed to enhance the performance of the conventional fabric filter systems and its performances were evaluated to compare to that of the existing dust collector. The pressure drop rapidly increased with increasing the elapsed time and the face velocity in two filtration systems. But the increasing ratio of a hybrid dust-collector compare to the existing dust collector was lower. This results were confirmed from the performance such as cleaning interval, residual pressure drop and dust loading rate. The overall collection efficiency of the hybrid dust-collector was more than 99.6% and this showed a improvement of 0.6～2% than that of the existing dust collector. Especially, the fractional collection efficiency at the particle size of around 1${\mu}{\textrm}{m}$ is about 4% higher than that of the existing dust collector.

• 한국대기환경학회지
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• 제16권2호
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• pp.179-190
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• 2000

The main object of this study was to investigate experimentally the characteristics of electrostatic cyclone-bag filter with upper tangential inlet in order to overcome the low collection efficiency for the submicron particle and high pressure drop which were main problems of general fabric bag filters. The experiment was carried out for the analysis of collection efficiency and pressure drop of electrostatic cyclone-bag filter comparing to those of fabric bag filter with various experimental parameters such as the inlet velocity(filtration velocity) and applied voltage etc. In the results the upper tangential inlet type showed higher collection efficiency for submicron particles below 2 ${\mu}{\textrm}{m}$ in diameter than that of center inlet and over 99.9% for overall collection efficiency. Pressure drop reduction ratios were shown as 40-50% for the applied voltage 0kV by centrifugal force and 70-90% for 20k V by the centrifuga and electrostatic force with the tangential inlet velocity (12-21m/s)

• 동력기계공학회지
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• 제8권2호
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• pp.31-38
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• 2004

The main purpose of this study is to investigate the characteristics of hybrid collection system combined with centrifugal force of cyclone and filtration of bag filter in one unit system. The experiment and numerical simulation are executed for the analysis of collection efficiency and pressure drop characteristics of hybrid system in comparison with those of a general fabric bag filter with the various experimental parameters such as inlet velocity(filtration velocity), dust concentration and dust type, etc.. In present system, dust particles tangentially coming into the system body are controlled by the centrifugal force effect, and the next collection is made out by the filtration mechanism in the fabric filter media. Therefore, the effective first collection causes the decrease of dust loading on the fabric filter, and it presents quite a lower pressure drop of fabric filter than that of a general fabric filter. At the inlet velocity, $21{\sim}27m/sec$ and inlet concentration(fly ash) $300mg/m^3$, pressure drops through the filter media of hybrid system are shown lower as $10{\sim}22mmH_2O$ comparing to those($17{\sim}33mmH_2O$) of a general fabric bag filter.

• 한국산업보건학회지
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• 제15권3호
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• pp.166-175
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• 2005

Health effects associated with metal working fluid (MWF) exposures include dermatitis, respiratory disease, hypersensitive pneumonitis, and asthma. Frequently, occupational exposures to MWFs are controlled by ventilating an enclosure with an air cleaning unit that includes a fan preceded by various kinds of filtration. There are several kinds of air cleaning units used in machining centers. But the associated troubles have hindered from efficiently using these devices. The main problem is the relatively short period of filter replacement. The reason is that the air cleaning units usually do not have the de-oiling systems, thus leading the earlier clogging of filters and reducing the flow rate of hood. Thus, the first stage of study was conducted to overcome this problem by developing the new oil mist collector equipped with the easy de-oiling system. The principle of de-oiling is that the centrifugal force generated by spinning the drum covered by filter fabric separates oils from the filter fabric. It would be very similar to the spin-dry laundry. By adopting this de-oiling technique, the problems associated with the conventional oil mist collectors could be solved. Several tests/analyses were performed to make the lab-scale oil mist collector. The collection efficiencies and the de-oiling efficiencies of commercially available filter fabrics were tested. Subsequently, the endurance test were conducted by observing SEM photos of filter fabrics and measuring tensile strength/expansion coefficient after spinning the filter drum for 20 minutes at the different rotation speeds. By doing these experiments, the most appropriate filter fabric and rotation speed/duration were selected. Finally, the new oil mist collector was designed. In the near future, this device must be tested in the real machining center.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.406-410
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• 2002

A new spin filter consisting of $50{\mu}m$ (nominal pore size) depth fitters rolled on a stainless steel grid was developed, using Saccharomyces cerevisiae as a model suspension cell to evaluate the spin filter performance. In a 1.8-1 fermentor with a rotation speed of 300 rpm and perfusion rate of 4 ml/min, a cell concentration of 49 g/l and ethanol concentration of 45 g/l from 100 g/l glucose could be obtained in a perfusion culture. The major mechanisms for cell separation used by the large-pore spin filter appeared to be centrifugal force and pivotal movement of the cells in the spin filter.

• Journal of Advanced Marine Engineering and Technology
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• 제41권1호
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• pp.44-49
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• 2017

본 연구에서는 선박 엔진 오일을 여과하는 검증된 기술인 원심정화기(Centrifugal Filter)를 이용하여 수분배출 구조를 설계하고 적용함으로써, 원심 청정기 시스템(Centrifugal Purifier System)을 개발하고자 한다. 선박엔진에서 윤활 및 냉각을 담당하는 오일은 시간이 경과할수록 미세입자 슬러지가 증가하고 때로는 수분의 유입에 따라 원래의 기능을 담당할 수 없게 되어 엔진내부에 치명적인 기계적 손상을 초래한다. 따라서 수분 제거 원리 고안 및 검증, 적절한 배출 구조 설계를 연구하였으며, 개발된 제품은 공인시험을 통해 유효함을 검증하였다. 이는 실제 선박에서 절실히 필요한 엔진 오일의 수명 연장 및 폐오일 감소, 기계 부품 손상 저감 등에 기여할 것으로 기대한다.

• 한국유체기계학회 논문집
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• 제6권2호
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• pp.15-22
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• 2003

Comprehensive study on a centrifugal blower for air-purifier involving a few physical filters for percolation process has been accomplished for an optimal design of the air handling system. The filtering media causes a flow resistance for induced flows by a rotating impeller. The present methodology is to adopt PIV system for velocity measurements and wind tunnel connected with an anechoic chamber for total performance test of the blower. Trial prototypes for the blades of a rotor and casing are presented for satisfaction of both flow rate and noise level set by design objectives. Tapered blades with a special casing for a fan show good performance data. The results of velocity fields also explain the reason of improvements of the blower performance.

• Journal of Advanced Marine Engineering and Technology
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• 제38권10호
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• pp.1251-1256
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• 2014

The use of lubrication oil is of many purposes and one among them is to drive the engine mounted on a ship. Hence the supply of clean lubrication oil is important. And an oil purifier is one of key components in marine diesel engines. At present, the element type full-flow oil filter has been widely used for cleaning the engine oil. The self-driven centrifugal oil purifier is a device which is used to remove the impurities in lubrication oil using a jet flow. The flow characteristics and the physical behaviors of particles in this self-driven oil purifier were investigated numerically and the filtration efficiencies were evaluated. For calculations, a Computational Fluid Dynamics method is used and the Shear Stress Transport turbulence model has been adopted. The Multi Frames of Reference method is used to consider the rotating effect of the flows. The influence of centrifugal forcehas been numerically investigatedto improve filtration efficiency of tiny particles. As a result of this research, it was found that the particle filtration efficiency using the only center axis rotating and outer wall rotating system are higher than that of the fully rotating system in the self-driven oil purifier.