• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.272-280
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• 2009

In this study is performed to investigate the pumping characteristics of three-stage disk-type molecular drag pump (DTDP). The experiments are measured using five vacuum pressure gauges in the positions for rotors of DTDP. The experimented DTDP is consisted of three rotors and four stator. In the DTDP, spiral channels of three rotors are cut on the both upper surface and lower surface of a rotating disk, and corresponding stator is a planar disk. The experiments are performed in the outlet pressure range of $0.2{\sim}533\;Pa$. The pressure of each rotors are measured under the various condition of outlet pressure and throughputs, and nitrogen gas is used for test gas. In the numerical study, the pumping characteristics of each rotor are studied for the variation of throughputs in the all rotating channel. Pressure contour and velocity are obtained by the numerical simulation.

• Journal of the Korean Vacuum Society
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• v.4 no.4
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• pp.343-349
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• 1995

게데형 분자드래그펌프의 배기특성을 강구(hard sphere)분자모델과 NTC(No Time Counter)충돌 scheme을 이용한 직접모사 법의 하나인 DSMC(direct simulation Monte Carlo)방법을 이용하여 해석하였다. 해석에 사용된 모델은 높이가 일정하고, 길이가 높이의 1~3000배 사이인 이차원 채널이다. 자유분자영역으로부터 연속체 영역까지의 영역에서 최대압축비와 배기속도를 계산하였다. 계산결과 기존의 최대압축비 이론 결과는 채널내의 압력변화가 클 때는 큰 오차를 유발하는 것을 알 수 있었고, 유동방향의 기체분자의 통과확률은 채널 길이와 출구압력에 관계없이 거의 일정한 값을 갖는다는 것을 발견하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.02a
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• pp.56-56
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• 2007

• Proceedings of the Korean Vacuum Society Conference
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• 2006.02a
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• pp.61-61
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• 2006

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.77.2-77.2
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• 2005

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2725-2730
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• 2007

Turbo-type molecular drag pumps ( MDPs ) are used in the liquid crystal display ( LCD ), semiconductor and other thin film industries. Siegbahn ( disk-type ) molecular drag pumps are used as high-pressure stages in the hybrid-type turbomolecular pumps, where they can operate in the viscous, the transition and the free molecular flow regime. In this study is performed to investigate the pumping characteristics of three-stage disk-type molecular drag pump ( DTDP ) in the molecular transition flow region. The experiments are measured using five vacuum pressure gauges in the positions for rotors of DTDP. The test is performed with nitrogen gas ( $N_2$ ).

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2723-2728
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• 2008

The present study is numerically and experimentally performed to reveal the pumping characteristics of a helical-type molecular drag pump (HTDP) in the molecular transition flow region. In the experimental study, the pressures are measured simultaneously at the 5 positions along the helical channel of rotor under various conditions of outlet pressure and throughputs, and nitrogen is used as test gas. The outlet pressure is in the range of 26-533 Pa. As results, the local pressure changes are checked corresponding to the various outlet pressure and throughput of HTDP. In the numerical study, Navier-Stokes equations with slip boundary conditions are employed (Re< 1000, Kn< 0.1). The local pressure distribution and the pumping speed are calculated. The numerical results are compared with the experimental results. The numerically computed value agrees with the experimental data within an error of approximately 5%.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.555-560
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• 2000

An experimental study on pumping characteristics of various turbo-type drag pumps is purformed. The inlet pressures are measured for various outlet pressures of the test pump. The maximum compression ratios for nitrogen are 100,000(Disk-type drag pump+ turbo molecular pump), 10000(Helical-type drag pump+turbo molecular pump), 850 (Helical-type drag pump), 100(disk-type drag pump).

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.372-372
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• 2008

• Proceedings of the Korean Vacuum Society Conference
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• 2005.08a
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• pp.185-186
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• 2005