• 제목/요약/키워드: Pumping Speed

검색결과 160건 처리시간 0.027초

Ion Pump Design for Improved Pumping Speed at Low Pressure

  • Paolini, Chiara;Audi, Mauro;Denning, Mark
    • Applied Science and Convergence Technology
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    • 제25권6호
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    • pp.108-115
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    • 2016
  • Even if ion pumps are widely and mostly used in ultra-high vacuum (UHV) conditions, virtually every existing ion pump has its maximum pumping speed around 1E-6 mbar (1E-4 Pa). Discharge intensity in the ion pump Penning cell is defined as the current divided by pressure (I/P). This quantity reflects the rate of cathode bombardment by ions, which underlies all of the various pumping mechanisms that occur in ion pumps (chemisorption on sputtered material, ion burial, etc.), and therefore is an indication of pumping speed. A study has been performed to evaluate the influence of magnetic fields and cell dimensions on the ion pump discharge intensity and consequently on the pumping speed at different pressures. As a result, a combination of parameters has been developed in order to design and build an ion pump with the pumping speed peak shifted towards lower pressures. Experimental results with several different test set-ups are presented and a prototype of a new 200 l/s ion pump with the maximum pumping speed in the 1E-8 mbar (1E-6 Pa) is described. A model of the system has also been developed to provide a framework for understanding the experimental observations.

희박기체영역에서의 나선형 홈을 가진 원판형 드래그펌프의 배기속도에 관한 실험적 연구 (An Experimental Study on Pumping Speed of Disk-Type Drag Pumps for Spiral Channels in Rarefied Gas Flows)

  • 권명근;양성민;이승재;황영규;허중식
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.2101-2104
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    • 2003
  • Experimental investigations are performed for the rarefied gas flows in a disk-type drag pump (DTDP). The pump considered in this paper consists of grooved spiral channel on rotors and planar stators. The flow-metre method is adopted to calculate the pumping speed. Compression ratio and pumping speeds for the nitrogen gas are measured under the inlet pressure range of $0.001{\sim}4$ Torr. The maximum of compression ratio was about 3300 for three-stage DTDP, 1000 for two-stage and 100 for single-stage DTDP at zero throughput. The number of stage influences the pumping speed of DPDT

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터보형 원판형 드래그펌프의 배기특성에 관한 실험적 연구 (An Experimental Study on the Pumping Performance of the Turbo-Type Disk-Type Drag Pump)

  • 황영규;허중식;권명근;이승재
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2002년도 학술대회지
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    • pp.577-580
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    • 2002
  • In this paper, the pumping performance of the disk-type drag pump which works in the outlet pressure range from 4 to 0.001 Torr is studied experimentally. The pumping characteristics of various drag pumps are performed. The inlet pressures are measured for various outlet pressures of the test pump. The flow-meter method is adopted to calculate the pumping speed. Compression ratios and pumping speeds for the nitrogen gas are measured. The present experimental data show the leak-limited value of the compression ratio in the molecular transition region. The rotational speed of the pump is 24,000rpm. The inlet pressures are measured for various outlet pressures of the test pump. The ultimate Pressures for zero throughput are measured for three-stage, two-stage and single-stage disk-type, respectively.

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리니어형 자속펌프의 이동자장 속도에 따른 충전전류 특성 해석 (Analysis of Charging Characteristics of Linear Type Magnetic Flux Pump Depended on Traveling Speed of Magnetic Field)

  • 정윤도;김현기;배덕권;윤용수;조현철;고태국
    • 한국초전도ㆍ저온공학회논문지
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    • 제12권1호
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    • pp.47-51
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    • 2010
  • We already obtained magnetic behavior of superconducting Nb foil of linear type magnetic flux pump (LTMFP) by means of the FEM analysis. As well as, fundamental equations of pumping current were theoretically derived based on the pumping sequences according to the position of normal spot of the moving flux. In this paper, we experimentally investigated pumping performances of LTMFP with a wide range of traveling speed of magnetic field. In order to confirm the numerical and theoretical approaches, we explained the pumping characteristics of LTMFP by use of the calculation sequence of pumping current.

Vacuum system design of a 10 ton/day class air liquefaction cold box for liquid air energy storage

  • Sehwan, In;Juwon, Kim;Junyoung, Park;Seong-Je, Park;Jiho, Park;Junseok, Ko;Hankil, Yeom;Hyobong, Kim;Sangyoon, Chu;Jongwoo, Kim;Yong-Ju, Hong
    • 한국초전도ㆍ저온공학회논문지
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    • 제24권4호
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    • pp.65-70
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    • 2022
  • A vacuum system is designed for thermal insulation of a 10 ton/day class air liquefaction cold box for liquid air energy storage. The vacuum system is composed of a turbomolecular pump, a backing pump and vacuum piping for the vacuum pumps. The turbomolecular pump is in combination with the backing pump for pumping capacity. The vacuum piping is designed with system installation conditions, such as distance from the cold box, connections to vacuum pumps and installation space. The capacity of the vacuum pump combination, namely pumping speed, is determined by analysis of the vacuum system, and pump-down time to 1×10-5 mbar is estimated. Vacuum piping conductance, system pumping speed and outgassing rate are calculated for the pump-down time with the ultimate pumping speed range of the vacuum pump combination of 1400 - 2300 l/s. Although the pump-down time gets shorter by larger capacity vacuum pumps, it mainly depends on target vacuum degree and outgassing rate in the cold box. The pump-down time is estimated as 3 - 6 hours appropriate for cold box operation for the pumping speed range. Considering the outgassing rate has uncertainty, the vacuum pump combination with pumping speed of 1900 l/s is chosen for the vacuum system, which is middle value of the pumping speed range.

PV Water Pumping 시스템을 위한 BLDC 모터 제어 (Brushless DC Motor Control for Photovoltaic Water-Pumping System)

  • 김성남;최성호;조정민;전기영;이승환;한경희
    • 전기학회논문지P
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    • 제50권3호
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    • pp.109-116
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    • 2001
  • In this paper, we adapted BLDC motor to PV water pumping systems to maintain high efficiency in the wide speed area. Also, to design confidence we adapted the vector control that drive the maximum torque at each speed limit. We designed optimal gain value of current, speed and pressure PI controller. Inverter gate pulse used Space Vector PWM to reduce torque pulsation of BLDC motor. According to, it was improve general matters of high water storage tank method by direct water supply pumping method.

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동작 전류에 의한 Magnetic fluid Linear Pump의 동특성 해석 (Analysis of the Driving Characteristics in the Magnetic Fluid Linear Pump by Operating Current)

  • 서강;박관수
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제53권4호
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    • pp.237-246
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    • 2004
  • The advantages of the Magnetic Fluid Linear Pump(MFLP) is that this device could Pump the non-conductive. non-magnetic liquid such as Insulin or blood because of the segregation structure of the magnetic fluid and pumping liquid. In this device. the sequential currents are needed to Produce pumping forces so that Pumping Forces and Pumping speed mainly depend on the current Patterns. The excessive forces at Pumping moment could cause the medical shock, and weak forces at intermediate moment could cause the back flow or the pumping liquid. So the ripples of the pumping forces need to be reduced for the medical application. In this research, the driving characteristics in the MFLP by operating current is analysed. The change of magnetic fluid surface according to the driving currents could be obtained be magneto-hydrodynamic analysis so that Pumping fortes could be computed by integration of the surface moving to the pumping direction at each moment. The actual MFLP with 13mm diameter was made and tested for experiments. The effects of driving current and frequency on the pumping forces and pumping speed were analyzed and compared with experimental measurements.

터보분자펌프 역류특성의 준정량적 평가 (Quasi-quantitative estimation on backstreaming characteristics of a turbomolecular pump)

  • 인상렬;박미영
    • 한국진공학회지
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    • 제10권1호
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    • pp.1-9
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    • 2001
  • 터보분자펌프의 배기성능은 회전자가 돌고 있을 때 순방향과 역방향으로의 배기속도(통과확률$\times$입구컨덕턴스) 및 두 방향으로의 기체 유량(배기속도$\times$입구 압력)의 상호관계에 의해 영향을 받는다. 펌프의 성능을 나타내는 가장 중요한 항목인 배기속도는 순유량, 즉 반대 방향으로의 유량의 차이를 흡기구 압력으로 나누어준 것이며, 최대압축비는 순방향 배기속도를 역방향 배기속도로 나누어준 것이다. 이들 방향성 고유특성은 서로 영향을 미치고 있으며 양쪽 입구 압력 모두의 함수이므로 관련 요소들을 서로 구분하기가 힘들지만 배기속도와 최대압축비의 측정결과를 잘 분석하면 준정량적인 해석이 가능하다.

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침투자속의 위치와 이동속도에 따른 리니어형 자속펌프 충전전류의 이론적 해석 (Theoretical Analysis of Charging Current of Linear Type Magnetic Flux Pump According to the Penetrated Position and Moving Speed of Magnetic Flux)

  • 정윤도;배덕권;윤용수;고태국
    • 한국초전도ㆍ저온공학회논문지
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    • 제11권1호
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    • pp.39-44
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    • 2009
  • We proposed a linear type magnetic flux pump (LTMFP) as a power supply for superconducting magnet system. In order to explain the operating mechanism of pumping action, the pumping sequence based on penetrated position and moving speed of magnetic flux on the superconducting Nb foil should be understood. In this paper, we induced a theoretical equation for pumping current of LTMFP according to the position of normal spot and corresponding equivalent circuit. In addition, current charging tendencies under the intensity of magnetic flux and frequency were described based on the theoretical pumping equation.

고강도콘크리트의 고속펌핑을 위한 압송성평가 및 예측모델에 관한 연구 (Development of Evaluation and Prediction Model for Concrete High Speed Pumping)

  • 김형래;조호규;정웅택
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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    • pp.201-203
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    • 2012
  • The establishment of the technology for evaluating friction resistance and pipe pressure and the relation of the fluid characteristics and pumpability of concrete is essential for the evaluation of concrete pumping performance for high speed construction of super-tall building. So, this study focuses on quantitative evaluation of concrete fluid characteristics and surface friction resistance under the change of concrete mix proportion and pumping condition. In this study, we measured the rheology of concrete and pipe pressure and surface friction characteristics when pumping. And, relations between the rheology characteristics of concrete and pumping performance was investigated by experiment. As the result of the experiment, high regression between the surface friction and pressure gradient was confirmed. And, prediction model to evaluate the friction resistance coefficient and pipe pressure reduction coefficient was suggested.

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