Interference issues with vortex flowmeters
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A new vortex flow meter has been installed to measure the steam consumption of the evaporator. The requirements regarding the straight pipe sections were met, and all settings were adjusted in accordance with the instructions. However, even when steam usage was stopped, the meter still showed a flow rate of 5.6 T. The manufacturer suggested that vibration at the installation location of the meter might be the cause, but there is no vibration present at the site. Could anyone help analyze what other factors could possibly cause such interference? !
Vortex flowmeters continue to display flow rates even when there is no flow of fluid in the pipe, and they do not return to zero. Manufacturers often attribute this to vibrations in the pipeline, but even when all equipment in the plant is shut down, these flowmeters still exhibit fluctuations and fail to return to zero, especially those used for measuring gases. Based on the principle behind its measurement, I wonder whether sound waves or other air vibrations could cause airflow within the tube, thereby resulting in a non-zero measurement value.
It involves closing all the valves before and after the flow meter; the flow meter still has an indication of instantaneous flow. I’d appreciate some advice from those who are more experienced~~
Is there a place for venting between the valves before and after the flow meter? If so, try venting and see what happens; I’ve encountered this situation where the reading returns to zero after venting, though the exact reason is unknown
Let’s see how large the value is; is it possible to make a cut?
However, vortex flowmeters still show some flow rate when the system is shut down, which indicates a problem with the zero point. In the case of intelligent flowmeters, the zero can be reset using a handheld controller; for analog flowmeters, the manufacturer must use a specialized module to address this issue, otherwise the device needs to be sent back to the factory for calibration. Additionally, it is possible to remove low-level signals within the permitted range
To perform a low-level signal rejection, it is first necessary to ensure that there are no vibration sources causing interference
What about signal shielding if there is no vibration at the site? What about the grounding of the table itself?
Clean it, the vortex generator, and check again to see if the connections of the sensing elements are loose.
If the flow rate remains constant, it could be due to power supply interference or frequency conversion interference. I’ve encountered a situation where an instrument with a 150-mm diameter, powered by frequency conversion, kept showing a flow rate; the problem was resolved only after moving the instrument
Signal shielding check: properly grounded； Today’s flowmeters also need to be grounded; that will resolve the issue. If it doesn’t return to zero, it will at least get close to zero, after which resetting or filtering out weak signals will suffice
If there is airflow or vibration in the pipeline, it will cause small signals in the vortex flow meter. Try grounding it; on the other hand, when the quality is poor, the flow meter exhibits zero drift, and this is a common problem with domestic flow meters. Our company once used vortex flowmeters from a factory in Tianjin, and the same issue occurred; we had no choice but to replace them.