• International journal of advanced smart convergence
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• v.6 no.4
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• pp.1-8
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• 2017

In this work, the effects of fairly influential factors on performance of vacuum system, such as constant pressure and outgassing effect were simulated to propose the optimum design factors. Outgassing effects of selected vacuum materials on the vacuum characteristics were simulated by the $VacSim^{Multi}$ simulation tool. This investigation examined the feasibility of reliably simulating the outgassing characteristics of common vacuum chamber materials (aluminum, copper, stainless steel, nickel plated steel, Viton A). The optimum design factors for vacuum systems were suggested based on the simulation results. And, the effects of throttle valve applications on vacuum characteristics were also simulated to obtain the optimum design model of variable conductance on high vacuum system. Simulated vacuum characteristics of the proposed modelling were agreed with the observed experimental behaviour of real systems. Pressure limit valve and normally on-off control valve were schematized as the modelling of throttle valve for the constant process-pressure. Simulation results were plotted as pump-down curve of chamber and variable conductance of throttle valve. Simulated behaviors showed the applications of throttle valve sustained the process-pressure constantly, stably, and reliably.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.95-95
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• 2012

우성 진공(크라이오 펌프), 제일 진공(터보 펌프)의 개발 시제품을 나노종합 팹센터(크라이오 펌프는 Sputter 장비, 터보 펌프는 Etcher 장비에 부착)에서 공정 신뢰성 Test 실시함.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.59-59
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• 2012

Vacuum pumping remains central to the performance and economy of many manufacturing processes, scientific instruments and scientific research. More vacuum is being used in many of the latest or leading edge manufacturing processes: Current examples include 3D semiconductor devices, EUV lithography, 450 mm silicon wafers, AMOLED displays, LEDs, Lithium-ion batteries and steel degassing. In other applications, vacuum pumping technology developments have led to much lower product costs which for example have enabled mass spectrometers to become a ubiquitous tool is life science research. Vacuum pumps have continuously evolved during the past 100 years of vacuum-based industrial processing but remain a key component which is often on the critical path of process and product improvements. This is especially so in the growing number of applications where the pumps are highly stressed. This presentation outlines significant developments in vacuum that have brought about this progress. The likely course of continued improvements is discussed in terms of increased performance and reliability, robust by-product handling, better cost efficiency and reduced environmental impact especially power consumption.

• Journal of the Semiconductor & Display Technology
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• v.8 no.1
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• pp.7-12
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• 2009

The outgassing effects of selected vacuum materials on the vacuum characteristics were simulated by the $VacSim^{Multi}$ simulation tool. This investigation examined the feasibility of reliably simulating the outgassing characteristics of common vacuum chamber materials (aluminum, copper, stainless steel, nickel plated steel, Viton A). The optimum design factors for these vacuum systems were suggested based on the simulation results. The baking-out effects of the modeled systems and materials on the performance of the vacuum system were also analyzed. The simulation predicted that the overall outgassing effect was more significant in the TMP system than in the DP system and that the utilization of a booster pump has a greater effect on the evacuation time than on the ultimate pressure.

• Journal of the Korean Vacuum Society
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• v.13 no.2
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• pp.47-53
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• 2004

A getter pump test system is being developed as a core item of the national project for establishing the foundation of the vacuum technology in our country. A preliminary test system was prepared for developing the getter test procedure, and providing design requirements and system specifications before setting up the getter pump test system. The pumping speed and the pumping capacity of getter elements of low activation temperature used in the seal-off vacuum devices, for the hydrogen, carbon monoxide and nitrogen gases, were measured using the preliminary test system. The pumping characteristics of a domestic getter, developed mainly for the gas purifier, were compared with those of a foreign getter used widely in the lamp factories.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2479-2483
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• 2012

This paper discusses the development of a personal compact oxygen generator for portable and mobility. The compact oxygen generator is operated with vacuum swing absorption by compact vacuum pump. The components of oxygen generator is composed on the miniaturization and weight reduction, and it is optimized by discharge pump speed, nozzle diameter and 3-way valve interval. In 0.5mm of nozzle diameter, $O_2$ concentration is approximately 37%, and flow rate is $1{\ell}$/min. On the 30cm away from the nozzle, $O_2$ concentration is increased approximately 0.5%.

• The KSFM Journal of Fluid Machinery
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• v.12 no.5
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• pp.19-24
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• 2009

This paper is performed to find out the stability of water-hammer in pipe line and pump station that is happened when additional water needs demanded. At first, the water supply construction project is planned to supply $6,000\;m^3/day$ through 17.9 km pipe line. But additional demand ($1,200\;m^3/day$) happened from Cheong-ra water reservoir. In this situation, air-chamber($4\;m^3$) and vacuum breaker valve(${\varphi}100\;mm$) are needed to prevent water-hammer. When the additional water is supplied, the existing facilities (air-chamber, vacuum breaker valve) are sufficient to alleviate shock not changing capacity alteration, judging from the airspace change and rise. Therefore, there is no problem for water-hammer by installing air-chamber($4\;m^3$) and vacuum breaker valve(${\varphi}100\;mm$) at the top of Yeo-ju hill.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.76-79
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• 2007

From the previous researches about flow characteristic of micro-nozzle， we found that viscosity and back pressure induced heavy losses in micro nozzle. To overcome thess losses, we began to study new conceptual micro propulsion system that is thermal transpiration based micro propulsion system. It has no moving parts and can pump the gaseous propellant by temperature gradient only (cold to hot). Most of previous research on thermal transpiration is in its early stage and mainly studied for application to small vacuum facility or gas chromatography in ambient condition using nanoporous material like aerogel. In this study, we focus on basic research of propulsion system based on thermal transpiration using polyimide material in vacuum conditions.

• Journal of the Korean Vacuum Society
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• v.20 no.6
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• pp.387-394
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• 2011

Standard devices and procedures for measuring the pumping speed, one of the most important parameters indicating the operation performance of the vacuum pump, have been developed and widely utilized. Though the standard system has a firm theoretical basis, it is, sometimes, inevitable to alter something in the system for a practical purpose compared with ideal conditions, which may lead to a large measurement error. In this paper, characteristics and systematic errors of various ideal or practical schemes for measuring the pumping speed are analyzed, and compensation terms are proposed.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.569-572
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• 2002

In the present study, flow simulations of a solution pump fer an absorption chiller are performed. The results are compared to the experimental data. Since the cavitation is more likely to occur in a solution pump due to Its operation under vacuum condition, and the cavitation was not considered in the present computations, the computed and experimental results show large discrepancies. For more accurate performance prediction of a solution pump, a cavitation model is required in the flow simulation. Flows through an inducer are also studied to see the effect of design parameters on performance characteristics. It is shown from the results that, if not properly designed, recirculation legion may exist near the hub region of the Inducer, and the suction surface may experience higher pressure than the pressure surface of the inducer, which may deteriorate the performance.