New method of a constant-pressure flowmeter traceability
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00177016%3A_____%2F23%3AN0000091" target="_blank" >RIV/00177016:_____/23:N0000091 - isvavai.cz</a>
Result on the web
<a href="https://www.nist.gov/system/files/documents/noindex/2023/05/22/CCM%20Program%20Book.pdf" target="_blank" >https://www.nist.gov/system/files/documents/noindex/2023/05/22/CCM%20Program%20Book.pdf</a>
DOI - Digital Object Identifier
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Alternative languages
Result language
angličtina
Original language name
New method of a constant-pressure flowmeter traceability
Original language description
Czech Metrology Institute covers the range of high vacuum by a primary standard based on the orifice-flow (also continuous or dynamic expansion) principle. A continuous and precisely determined gas throughput is admitted into a calibration chamber, which is pumped through a precise orifice by a known pumping speed. The calibration pressure in the chamber can be calculated as their ratio. The gas throughput must be generated by means of a suitable primary gas flowmeter. In our case, the utilization of two constant pressure flowmeters (CPF) was necessary to cover the entire demanded range of the generated pressures. Volume displacers of both flowmeters are based on directly compressed welded bellows (consisting of the welded metal foil annuli), each compressed by a screw driven by a step motor. After a fatal leakage had occurred in one CPF, the leaky welded below has been replaced with an identical one. Of course, its pressure-compression dependence of displaced volume had to be calibrated. On this occasion, the quicker calibration method has been developed. The new method utilizes a very slow but constant displacement of the piston with a tied-up but discontinuous volume-change of the bellow. Thus, a several times shorter calibration time can be achieved with the same or slightly lower uncertainty of the volume-change.
Czech name
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Czech description
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Classification
Type
O - Miscellaneous
CEP classification
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OECD FORD branch
20205 - Automation and control systems
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2023
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů