• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.4
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• pp.418-425
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• 1988

Since conventional computer program is workable only with velocity boundary condition, in practical fluid passage such as clean room which usually have wide inlets and outlets, it is not easy to measure velocity itself because of its vector property. Furthermore a certain assumption of velocity at boundaries may lead to physically unreasonable results. From this motivation, we have developed a computer program to predict whole flow field imposed on pressure-based boundary condition which can be measured by relatively simple method. The only additional velocity boundary condition that should be imposed on to make the problem unique, are no slip condition at all walls and zero cross stream velocity at inlet. The result of present study was compared with that by Bernoulli equation being used practically. They were coincident well each other within 5%, therefore the validity of the present method is proved. In the present work, the flow field in a clean room subject to pressure-based boundary conditions at an inlet and two exits was predicted numerically. The pressure difference between the inlet and the left exit which keeps relatively low pressure among two exits is fixed as 150[Pa] and the pressure at the right exit is varied from zero to 150[Pa] by the increment of 25[Pa]. For each cases the flow characteristics in the clean room, the velocity profile at the inlet, and the flow rate through the two exits was predicted. The flow rate through the right exit imposed on relatively higher pressure than the left exit decreased linearly according to the increase of pressure of the right exit. When the pressure of the right exit is increased enough to cause back flow at the exit, the flow rate is rapidly decreased.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.121-130
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• 2002

Clean stockers are being used by semiconductor and TFT-LCD manufacturers to store and buffer work in process. Since an important function of a stocker is to keep the contained material clean. The only way to keep the stored product clean is to provide constant clean airflow the product and through stocker, The airflow across the product prevent contamination from settling on the product. Up to now, stocker typically have been configured to receive their laminar airflow from fan filter units that are located on the side of the stocker This type of stocker may have such problems as complexity of structure, increment of temperature, mechanical vibration, initial investment and running cost. In this study, In order to solve the above mentioned problems, new air control system in stocker is proposed, which is to control open ratios of exits that are located on the side of the stocker without fan filter units. Open ratios of exits need to be optimized for the same quantities of airflow in each exit. In this study, static pressure regain was used for the analysis of the open ratios of exits theoretically and Blue Ridge Numerics FEM software, CFDesign, was used fur simulating airflow in stocker. As a result, Open ratios of exits important to provide constant clean airflow can be obtained by the analysis of static pressure regain and was verified by simulation results. Therefore, new air control system in stocker can be used by the semiconductor and TFT-LCD manufacturers.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.566-572
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• 2011

In recent semiconductor and FPD (Flat Panel Display) manufacturing processes, high clean-class delivery operation is required more and more for short working time and better product quality. Traditionally SLIM (Single-sided Linear Induction Motor) is widely used in the liner drive applications because of its simplicity in the rail structure. A magnetically levitated (Maglev) unmanned vehicle with SLIM traction, which is powered by a CPS (Contactless Power Supply) can be a high precision delivery solution for this industry. In this paper unmanned FPD-carrying vehicle, which can levitate without contacting the rail structure, is suggested for high clean-class FPD delivery applications. It can be more acceptable for the complex facilities composed with many processes which require longer rails, because of simple rail structure. The test setup consists of a test vehicle and a rounded rail, in which the vehicle can load and unload products at arbitrary position commanded through wireless communications of host computer. The experimental results show that the suggested vehicle and rail have reasonable traction servo and robust electromagnetic suspensions without any contact. The resolution of point servo errors in the SLIM traction system is accomplished under 1mm. The maximum gap error is ${\pm}0.25mm$ with nominal air gap length of 4.0mm in the electromagnetic suspensions. This type of automated delivery vehicle is expected to have significant role in the clean delivery like FPD glass delivery.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3413-3417
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• 2007

In recent semiconductor manufacturing clean rooms, air washers are used to remove airborne gaseous contaminants such as $NH_3$, SOx and organic gases from the outdoor air introduced into clean room. In the present study, an experiment was carried out to examine the improvement of removal efficiency for the gaseous contaminants. In order to improve the gas removal efficiency, a hot water contact heat exchanger was installed upstream of the air washer to heat and humidify the incoming outdoor air before entering the air washer.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.726-735
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• 2007

Inside the factory buildings of aprecision industry (which produces semiconductors or TFT-LCD), thousands of vibration-sensitive precision equipments operate in the clean rooms. Various utility equipments that are installed around them for proper operation cause various sources of noise and of vibration to exist inside the clean rooms and thus deteriorate the noise and the vibration environment within. In this study, we check if the existing transient vibration phenomenon is caused by the vibrations that arise from operating the utility installed near these equipments; compare and evaluate the vibration criteria of precision equipments regarding the transient vibration phenomenon; and check the efficiency of these criteria.

• Journal of The Korea Institute of Healthcare Architecture
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• v.27 no.3
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• pp.61-69
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• 2021

Purpose: Senior long-term care facilities are vulnerable to a cluster infection because of frequent physical contact, large group dining, communal living, and room sharing. This study aims to provide architectural improvement plans for a quarantine system in the facilities. Methods: Actual quarantine action data, guidelines from governments and institutes, in-depth interviews with facility staff are analyzed. Results: To prevent a cluster infection in the senior facilities, it is necessary to provide an architectural plan focusing on increasing the number of single rooms and isolation rooms, providing isolation rooms for staff, separation of a soiled room from a clean room, planing an entry vestibule and a visitor's room. Implications: It is important to analyze the existing condition of facilities that had been going through cohort isolation and provide the architectural solution to strengthen infection control.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.698-699
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• 2009

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.162-162
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• 2000

We describe a new optical-type guide sensor for AGV. It is robust the disturbance of the light. The developed optical-type guide sensor is very useful in the clean room environment where the light disturbance is very critical through the hole on the surface of the floor.

• Proceedings of the SAREK Conference
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• 2005.06a
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• pp.152-152
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• 2005

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.452-457
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• 2008

We performed a study on the contaminant transfer in a clean space for the location of product and fan filter unit using computational fluid dynamics analysis. To simplify the real product moving process, three different non-moving cases regrading the locations of product were selected: no product, at the lower side, and at the upper and lower sides. And to investigate the characteristics of the contaminant transfer, the arrangement of fan filter units was varied. Local mean air-age and contaminant distribution were used as evaluation indices. From the results, the contaminant transfer to the product was the most when the products were simultaneously located at the upper and lower sides. And the contaminant was easily exhausted regardless of the location of product when the fan filter units were properly arranged at the top side of the clean space.