How can unstable flow rates in electromagnetic flowmeters and vortex flowmeters be corrected?

Have it calibrated by a qualified institution, especially for external measurements.

If it’s unstable, increase the damping and try increasing the filtering

It seems that in Asia, there are only two companies capable of performing calibration for electromagnetic flowmeters. If one needs to calibrate such a device, they can first use a tank to hold a certain volume of the fluid, calculate that volume, and then do the same after the tank is emptied; of course, it’s essential to get the calculations right

For electromagnetic flowmeters, you can check the set parameters such as low-flow cutoff, damping, and deadband time. Are the vortex streets separate or integrated? Check whether the sensor is loose; high temperatures can also have an impact. There are too many situations!

I mean, it’s not that it’s unstable; it’s just not accurate. . . .

Unstable flow rate is a problem related to fluctuations in the operating conditions of the process medium, and it has little to do with the accuracy of the instruments. Even if the instruments are recalibrated 10,000 times, will that resolve the fluctuations in process operation? This kind of problem sounds like trying to reach the sky by climbing a tree – putting the cart before the horse. You have an irregular heartbeat; it’s useless to try to adjust the pulse measurement function of the ECG machine, right?

The instability of electromagnetic flowmeters is often caused by issues with the pipeline; you can check that aspect

For electromagnetic flowmeters, it is necessary to check whether there are any high-power electrical devices nearby that could cause interference, and whether the flowmeter is installed correctly Is it full? Could there be bubbles inside the pipe? Is the grounding ring properly connected? Is the ground resistance too low? Is the electrode dirty? Is there bubbling in the fluorinated lining? Check everything first; if that doesn’t work, consult the manufacturer’s technical experts. There are many amateurs at the manufacturer who are not as good as you. I’ve also encountered situations where the vortex flow meter showed a serrated pattern in the steam flow data – it’s necessary to check whether the steam pressure and temperature are stable. In my opinion, the most likely cause is improper installation, with steam containing liquid droplets, resulting in measurements of both gas and liquid components

None of the vortex streets on the device are accurate; I’m planning to replace them now, as low flow rates aren’t being displayed

It should not be possible to correct it; one needs to go to a unit with valid calibration qualifications to perform calibration using actual flow rates.