PTB News 2/2002 (149 kB) PTB News 2/2002, English edition, Issue August 2002The German national standard for high-pressure natural gas named “pigsar” is located at the Ruhrgas AG in Dorsten/Germany. Since recently PTB scientists can carry out calibrations and approval tests from as far away as Braunschweig by means of telecalibration. The method was demonstrated at an international conference in Washington via live connection to “pigsar”.
Calibration of industrial gas meters, i. e. ultrasonic or turbine gas meters with high-pressure na-tural gas, requires great technical effort. That is why there are only a few test set-ups operating in the world. The largest one (in terms of size and measurement capabilities) is called “pigsar” and is operated by Ruhrgas AG in Dorsten. This accredited test centre carries out verifications of gas meters and works as a DKD (German Calibration Services) laboratory. Since 1999 PTB has been using the test set-up on a contractual basis as the national standard for the realization and dissemination of the units of volume and flow rate of streaming gas under high-pressure conditions.
As “pigsar” is approximately 300 km away from Braunschweig, it was necessary to seek ways not only to monitor and control the tests remotely but also to comply with the stringent requirements of legal metrology. Via ISDN connection, the PTB scientists are linked with the database of the test set-up. They have access to all data of the test sample as well as to all measuring conditions and parameters, and they can follow the testing procedure online. If necessary, they can also intervene in the test sequence and control it. The parameters and the test results can be presented graphically and in tabular form. A high protection level is maintained for the required exchange of data.
At the 5th International Symposium for Fluid Flow Measurements in Washington in April 2002, the telecalibration of a gas meter at “pigsar” was demonstrated online. Apart from a presentation of the software, there was a TV live connection to “pigsar” to illustrate to the conference participants how calibrations are carried out on site. It was the first time world-wide that such an experiment in the area of flow measurement was carried out with success.