Hi All,
I have some 3051SFC meters that are in a lower than anticipated flow process.
The process also utilises a back pressure regulator on the downstream side to maintain pressure on the meter.
What I am seeing is that over a 24 hour period the DP is following a diurnal pattern.
From mid-late evening it is relatively flat DP (system is showing 0.02kPa), then in the morning as the temperature increases, the DP rises (up to 0.06 kPa DP), over the flow cutoff, and peaks around 11am.
The DP then suddenly drops over the midday-afternoon period (often to negative DP as low as -0.02 kPa reported) although the system will maintain an actual flow that will keep a flare burning (yes I know this doesnt have to be much but should the system be reporting negative at all if flow is present?). This then stabilises out in the mid-late evening- then recommencing the cycle again.
The meters never seem to zero correctly, although visits by techs to the field do not raise any issues from the systems.
Question:
1. Should we trim the DP zero at the time when the meter reads the most negative (but this would also boost the flow in the morning value- so leads to questions of accuracy)?
2. Can the DP value be completely dominated by temperature in this case?
3. Does this lend question to the accuracy of the meters as a whole?
As always, your knowledgeable help is greatly appreciated.
Thanks,
Kitndavj