AVS 50th International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeP

Paper VT-WeP3
Novel Calibration Apparatus for Precise Barometer and Vacuum Gauge

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: S.Y. Woo, Korea Research Institute of Standards and Science
Authors: S.Y. Woo, Korea Research Institute of Standards and Science
S.H. Kang, Korea Research Institute of Standards and Science
I.M. Choi, Korea Research Institute of Standards and Science
Y.J. Lee, Korea Research Institute of Standards and Science
Correspondent: Click to Email
In order to calibrate accurate absolute pressure gauges such as barometer and vacuum gauge, laser or ultrasonic mercury manometers have been used. However, complexity, harmfulness of mercury vapor, and cost of mercury manometers made it difficult to use in most calibration laboratories. As a substitute, a gas-operated pressure balance is used for calibration of such gauges. However, commercially available pressure balances cannot be suitable because consequent exposure of the piston and masses to the atmosphere raises the problem of contamination and the ingress of dust particles to the gap between the piston and cylinder. Moreover a lot of time is being spent in changing the mass combinations on the piston and breaking the vacuum each time when a different pressure point is required. To overcome these difficulties, we manufactured a novel weight-loading device for changing the masses in situ without breaking the vacuum. This device made it possible to add or remove weights easily in vacuum, thereby greatly reducing the time between measurements. Using this device, we could easily calibrate precise quartz resonance barometers from 940 hPa to 1050 hPa. Moreover we also found that with new calibration technique this device could be used very efficiently for the calibration of vacuum gauge in the range of 100 hPa full scale. In this paper, practical calibration results are presented for a precise barometer (Paroscientific, Model 760-16B) and a vacuum gauge (MKS, CDG 100 Torr).