While studying the possibilities for calibration of different flow meters I am not finding straight forwards solutions...

The meters are differential pressure type flowmeters, working with orifice plates and pitot tubes as primaries.

They are installed on steam pipes carrying very high flow rates.

Can I calibrate on different fluid to steam and still obtain a valid calibration?

Can I calibrate on lower flow rates than the operation flows as they are extremely high?

 

All you can really calibrate is the DP transmitter part of the meter, yes you can use an accurate air pressure source or similar. Another way is to use a water column (plastic tube full of water) which you can raise or lower against a tape measure.

It would also be good to remove the orifice plate to ensure it's clean and hasn't eroded with time.
Roy

 

Since you are measuring a compressible fluid, you will also need pressure and temperature measurements. The pressure transmitter can also be calibrated with air, or with a dead weight tester. Temperature measurement typically is going to use a thermocouple which has a fixed calibration. If you are using an mv to I transmitter, follow manufacturer's instructions.