Are there any instruments for online verification of flow meters?
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If I have a flow meter on site and it’s not possible to stop the operation in order to remove it for calibration, how can I perform calibration online? Are there any instruments available for this purpose? For example, my flow meter is from Yokogawa. Thank you all for your help
For liquids, it might work. Find a tank with higher precision, and use changes in liquid level to correlate them with the flow meter readings. In particular, Yokogawa’s electromagnetic flowmeters feature high accuracy and reliability, as well as an accumulation function; earlier models also had a batch function, and online calibration or verification is possible. Gases are a bit unreliable.
I don’t think online verification is likely； If verification also requires many auxiliary devices (as LS said). A portable ultrasonic flow meter can be used for comparison, but the accuracy cannot be guaranteed.
What should be done if the flow meter is found to be inaccurate? Does one have to take it apart and send it to the manufacturer for calibration?
Installing two flow meters for comparison seems a bit costly, haha.
Reply to 4# ksme200811: We generally don’t use it for measurement purposes； If it breaks, replace the board and reset the parameters; accuracy at a basic level is sufficient ； There are no plans for testing at the moment either.
Are you calibrating the measuring element or the transmitter? Generally, it is the transmitter that needs to be verified, and 802 can be used.
Reply to 7# yujigongwu: The sensor and transmitter are combined together. But what kind of calibration device is 802?
Our approach is to keep a flow meter that has been calibrated by a certified laboratory; if the accuracy of the process measurement drops, we replace it immediately. Electromagnetic flow meters are generally quite accurate, provided they are installed correctly and there are no faults with them.
Reply to 8# ksme200811: If it is a vortex flow meter, it should be able to measure frequency; mass flow meters generally do not require calibration. 802 is a type of calibration instrument that can apply pressure and measure the signal in the circuit. I think regarding your analysis, it’s not certain whether it’s indeed a fault with the instrument; sometimes process-related factors can easily lead to inaccurate measurements, such as the absence of or inappropriate temperature and pressure compensation, or dirt on the sensing elements.
The Yokogawa electromagnetic flowmeters in our workshop are also experiencing the same problem mentioned by the original poster; the issue was identified as a significant discrepancy in the cumulative readings between the outlet flowmeter of Tank 1 and the inlet flowmeter of Tank 2