Signal interference in vortex flowmeters for gas flow measurement?
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There is a vortex flow meter at the front end of our device, with a measurement range of 0–700 m3/h; when there is no flow, it shows a value of over 100. When power is supplied to an inverter in the system, the reading experiences significant fluctuations. As soon as a vacuum pump controlled by the inverter starts operating, the value reaches 700. After that, I turned off the other devices, and when air flow was allowed in, the reading was around 80, which is not very different from the actual value. But as soon as I powered on the frequency converter and started the vacuum pump, things returned to their previous state. Is there any expert who can help me answer this? :)
Before installation, the product manual should be read carefully; avoid sources of vibration, as vibrations in the pipes have a significant impact on the flow meter’s measurements.
Vortex flowmeters are most sensitive to vibration, as it can generate false signals. It is recommended to take isolation measures. http://www.shakic.com/cp/wojiellj.htm
Thank you for the answer! I think pipe vibration can’t be the only reason, as I haven’t started any rotating equipment and no air is flowing through the pipes; yet there are significant fluctuations just by powering on the frequency converter.
Vortex streets are primarily affected significantly by vibrations; keep this in mind
Do frequency converters cause interference? How to eliminate it?
Apply a filter to the vortex flowmeter signal
The biggest enemy of vortex flowmeters is interference, as these meters rely on measuring the frequency of vortices for measurement; they deal with frequency signals. Frequency signals such as electromagnetic waves and vibration frequencies can interfere with vortex flowmeters, and this interference is the main reason for inaccuracies in their readings.
Check for interference! Check if it’s the joke interfering!
This post was last edited by yandeya on 2010-9-24 at 20:22. The reason for the fluctuations in flow rate of your vortex flow meter is related to interference from the frequency converter. Solutions: 1. If it is a non-shielded signal cable, it should be replaced with a shielded one (a three-core cable is preferred, preferably a triple-twisted shielded cable), and ensure that the signal cable of the flow meter is properly shielded and grounded. 2. If the flow meter signal wires and the variable-frequency motor wires are laid in the same cable tray, they should be separated by layers or laid separately. 3. Where possible, an isolation transformer can be used to reliably isolate the power supply of the flow meter.
You can connect a 250-ohm resistor in series with the signal wire of the flow meter; it will give good results. Give it a try, or use a signal isolator