PTB > Structure > Division 1 > Department 1.4 > Working Group 1.42 > Metrological testing and calibration
 
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Metrological testing and calibration
Among the most important tasks are the realization and dissemination of the legal units of volume (m³) and flowrate (m³/h) 
of gases in motion. For the performance 
of these tasks there are the following standard measuring devices at its disposal:

Bell prover (1 - 60 m³/h)

A bell prover which allows volume flowrates of air at atmospheric pressure to be realized with a measurement uncertainty of u < 0,06% serves as the primary standard. 

Piston devices (0,015 - 3,5 m³/h) 

Two piston devices with a contents of 20 dm³ and 60 dm³, respectively, allow gas meters to be calibrated with a 
measuremen t uncertainty of u < 0,05%.

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Bell prover

Nozzle test rig for large gas meters (2 - 5.600 m³/h) 

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The computer-controlled nozzle test rig consists of an echelon of 16 Venturi nozzles connected in parallel and operated at sound velocity. This mode of operation guarantees a very high stability of the flowrate selected, with short-term reproducibilities of 0,002%. The uncertainty of measurement amounts to u < 0,08%. 

Turbine gas meter test rig (200 - 16.000 m³/h) 

For the calibration of gas meters of up to 16.000 m³/h, a test rig is available which is equipped with two turbine gas meters as standard devices and allows a measurement uncertainty of u < 0,12% to be attained. 

The standards stated are used for the metrological testing and calibration of 

  • other standard devices of PTB, 
  • reference standard devices of the verification authorities, 
  • working standard devices of state-recognized test centres, 
  • standard devices for industry, 
  • and for the testing of transfer standards for national and international intercomparisons. 
In addition, efficient transportable transfer standards (sonic nozzles, standard wet gas meters, vane gas meters with servo drive, turbine gas meters etc.) are available to disseminate the units of volume and flowrate. 

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Transportable transfer standards (0,015 - 10 m³/h) 

© Physikalisch-Technische Bundesanstalt
Last Update: 06-01-2007, Volker Strunck