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| LOW ABSOLUTE PRESSURE
LABORATORY |
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Quantity - pressure and flow under
vacuum and molecular flow conditions.
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Unit -
Pa, Pa·m3·s-1.
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Tasks of the
laboratory |
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The main task of
Laboratory is the realisation of a low absolute pressure,
parcial pressures and small flows.
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Available
metrological services |
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| Calibration
and Measurement Services |
Range |
Combined
Standard Uncertainty |
| Calibration
of vacuum gauges. |
1 kPa -
10 mPa |
0.1 % -
1.2 % |
| 1 mPa -
10-7 Pa |
(2 - 8)
% |
| Calibration
of helium leaks. |
1·10-2
- 1·10-10 Pa·m3·s-1
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(4 - 8)
% |
| Calibration
of oriffices conductivity, artificial
conductivity for molecular flow. |
10 -
1·10-8 Pa·m3·s-1
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(2 - 7)
% |
| Measurement
of small flow in condition of molecular flow. |
10 - 10-5
Pa·m3·s-1 |
(2 - 7)
% |
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Methods
of measurement: |
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- method of
dynamic expansion is used to increase the National
Standard range to 10-6 to 10-7 Pa.
The dynamic expansion is realized by flow through members
with known conductivity. |
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Instruments
in use |
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National
Standard - Compress mercury vacuum gauge of
McLeon type (range 1 kPa - 10 mPa, combined
standard uncertainty from 0.1 % to 1.2 %), stainless
steel construction (decreases error caused by
electrostatic charge arising from mercury motion in a
capillary), glass capillary d = 8 mm, 80 kg mercury,
construction eliminates the Ishii effect. Mercury column
height is red by telescope with readability 0.01 mm. |
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Capacitive
vacuum gauge with three sensors of 100 kPa, 10 kPa, 1 Pa. |
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Apparatus for
dynamic expansion in the range 10-2 to 10-6
Pa. |
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Quadrupole
mass spectrometer. |
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Apparatus for
glass pressure increase depends on time in known volume. |
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Set of liquid
flowmeter. |
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