Validation of a variable bell jar pressure as a method for primary generation of absolute pressure in the range from 100 Pa to 5 kPa |
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| J. Setina, J. Tesar, Z. Krajicek |
- Abstract:
- Generation of absolute pressure with a pressure balance is commonly done by enclosing the space above weights with a bell jar and evacuating it with a vacuum pump. Residual pressure in a bell jar is usually of the order of few tens of Pa to few Pa, depending on the effective pumping speed. Its value is added to a calculated pressure of the gravitational force of the piston and weights to obtain the generated absolute pressure. By connecting to the absolute pressure balance a precise and stable pressure gauge with sufficient resolution it is easy to observe that small changes of residual pressure in a bell jar generate a corresponding change in a pressure reading of the gauge. Unfortunately the lowest absolute pressure which can be generated by a pressure balance of conventional design is determined by the tare weight of the piston and some small additional weights necessary for sufficient minimum free rotation time and it is in the pressure range starting at 3 kPa and up to 5 kPa.
- Keywords:
- absolute pressure, primary generation of pressure, validation, variable bell jar
- Download:
- IMEKO-TC16-2007-094u.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC16
- Event name:
- Cultivating Metrological Knowledge
- Title:
- 3rd Conference on Pressure Measurement (together with 20th TC3 Conference on Measurement of Force, Mass and Torque & 1st TC22 Conference on Vibration Measurement)
- Place:
- Merida, MEXICO
- Time:
- 27 November 2007 - 01 December 2007