Hello all, I'm new here I'm Instrumentation Engineer working in oil & gas field in our site we have a lot of mass flow meters and calibration is done periodically from 2 weeks ago I calibrated a rosemount mass flow meter, the initial error was 0.1% after adjusting the mass calibration factor and took 3 consecutive runs the error reduced to 0.02% and this is acceptable then from 4 days ago I wanted to make a verification on the same mass flow meter and I found the error increased again to 0.1 % !! could anyone make it clear to me why this happens !? Note: the flow rate is constant in all runs (20 kg/min) and also the fluid density.... Waiting a helpful feedback. Thanks, boxyman
Hi boxyman,
This one is a little tough to troubleshoot without knowing a few key things. First off, is this a Rosemount 3095 or a Rosemount 3051SMV MultiVariable Mass Flow Transmitter? Secondly, are you seeing the error as a result of comparing the output of the transmitter to a calc data sheet or how exactly are you noticing it? Third, what is the process fluid that you are trying to measure?
If this is a pressure device, I may be able to help you out but if this is a coriolis meter, I may have to wait for one of my colleagues to respond. If you can get those couple questions answered, we might be able to point you in the right direction.
Regards,
Brian Fretschel
In reply to Brian Fretschel:
Hello Brian,
thanks for your fast respond
its rosemount IFT9701 Coriolis meter
I calibrate using gravimetric method by comparing the final output mass from flow meter to the mass on calibrated weigh scale
the fluid is a base oil
Regards
In reply to boxyman:
Hello Boxyman,
The best uncertainty value for a Micro Motion Coriolismeters with IFT9701 is 0.1%, although the accuracy depend on the sensor type connected to the IFT9701.
The values you report not unexpected, however I would like to look into your calibration process to determine if there are potential optimisation points.
Points of attention would be;
- Zero Verification and Calibration; Do you perform this check and if so how and when?
- Total system accuracy; How accurate is the weighscale and how is the calibration stand set-up?
It believe it might be usefull to discuss this further over the phone. Depending on your world area you can contact me (Central european time zone) or i can contact you with one of our Micro Motion experts in other world areas/time zones.
Arne Prins | Emerson Process Management | Field Application Engineer | Flow Group | Netherlands| T +31 318 49 5461 | Arne.Prins@emerson.com