The vortex flowmeter probe has been damaged by erosion
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Case Analysis: Date: 2017-6-26; Location: Yongheng Fabric Belt Factory; Subject: Vortex flow meter; Diameter: DN80; Fault: Unstable instantaneous flow rate – a relatively high flow rate was being displayed despite no steam being used on site. Process to resolve the issue of zero flow rate after closing the inlet valve: Checked that all parameter settings were correct, there were no interference signals at the site; the power was turned off and the signal board was replaced, but the problem persisted even after powering it back on. Suspecting a problem with the probe, the gas supply was stopped and the probe was removed; it was found that its outer protective casing was damaged. After replacing it with a new probe, power was supplied and the valve was opened, resulting in stable and accurate flow rates. When there is no air flow, the flow rate is zero, and the fault is resolved.
Our company has a vortex flow meter for measuring steam, made by Yokogawa. As soon as steam is introduced, it reaches the full scale. There is a very loud noise at the sensor unit on site, similar to the \"clanging\" sound produced when the valve core falls out and is pushed by the airflow; the noise disappears once the pipeline valve is closed, and the measurement value becomes zero. When measured with a multimeter, the resistance of the piezoelectric sensor relative to ground is normal. It is likely that either the piezoelectric sensor of the vortex flow meter is loose or the component that generates sound in the vortex flow meter has come loose or fallen off. We haven’t removed it for inspection yet; we plan to do so after the steam supply is stopped