AVS 49th International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeA

Paper VT-WeA10
A Compact Leak Rate Calibration System for Both Pressure and Vacuum Modes

Wednesday, November 6, 2002, 5:00 pm, Room C-104

Session: Vacuum Measurements, Components, and Control
Presenter: Xu Chen, Tsinghua University, P.R. China
Authors: Xu Chen, Tsinghua University, P.R. China
Ping Chen, Tsinghua University, P.R. China
Q. Zhang, Tsinghua University, P.R. China
Q. Liu, Tsinghua University, P.R. China
Liangzhen Cha, Tsinghua University, P.R. China
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To meet the quality control of the industrial leak detection, especially the growing demand in sniffing application, a compact leak rate calibration system is developed to calibrate the leak rate from high pressure to atmosphere (pressure mode) and from atmosphere to vacuum (vacuum mode). A new method based on constant volume change in pressure for pressure leak rate calibration is utilized. A differential capacitance diaphragm gauge (CDG) is used to markedly decrease the temperature effect. It is found that 1*10@super -5@ Pa*m@super 3@/s pressure leak rate at room temperature can be calibrated with an accuracy of better than ±5% (with confidential level 95% ) and leak rate as low as 3*10@super -6@ Pa*m@super 3@/s can be calibrated with an accuracy of better than ±15% with an environmental temperature change less than ±0.1°C. The total test period is about 30 minutes. This compact system is suitable for leak rate calibration in industrial environment for both pressure and vacuum modes.