Low-range flowmeters for use with vacuum and leak standards
Vacuum pressure standards of the orifice-flow type require known gas flows of 10/sup -6/ mol/s (10/sup -2/ atm cm/sup 3//s at 0 /sup 0/C) and less. Known gas flows can also be used to calibrate ''standard'' leaks by comparing the pressures generated when flows from the leak and the flowmeter are alternately passed through a constant conductance. Two constant-pressure, piston displacement flowmeters developed at the National Bureau of Standards are described that can generate flows between 10/sup -6/ and 10/sup -10/ mol/s with an estimated uncertainty of 0.8% to 2%. Comparisons of the flowmeters with alternate calibration techniques, and repeated low-range leak and vacuum gauge calibrations, have been used to confirm the estimated uncertainty and random errors of the flowmeter.
- Research Organization:
- National Bureau of Standards, Center for Basic Standards, Gaithersburg, Maryland 20899
- OSTI ID:
- 6876243
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Vol. 5:3
- Country of Publication:
- United States
- Language:
- English
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