1. Abnormal Cumulative Flow in Mass Flow Meter
Troubleshooting: A mass flow meter at a plant showed cumulative flow even when there was no process flow. Upon inspection, it was found that the supports at both ends of the sensor did not meet installation requirements. Specifically, the support distances were uneven, and the bottom of the supports was suspended above the ground, failing to provide adequate support.
Solution: The support components at both ends of the sensor were modified to meet the installation requirements.
Maintenance Summary: When installing a mass flow meter, it is essential to ensure that the sensor flange is parallel to the pipeline flange to avoid stress. In practical use, gravity causes the pipeline to sag over time. In this case, the support base of the sensor was suspended, failing to provide support. The stress from the sagging pipeline affected the measurement tube of the sensor, causing asymmetry or deformation of the detection probe, leading to zero drift and measurement errors in flow readings.
2. Fluctuating Display in an In-Use Flow Meter
Troubleshooting: A flow meter displayed fluctuating readings, with initial suspicion of poor wiring connections. After multiple checks and tightening of the wiring terminals, no improvement was observed. Further investigation revealed that the wiring between the converter and the sensor was loose.
Solution: The wiring between the converter and the sensor was re-tightened, resolving the issue.
Maintenance Summary: The initial assumption was interference, but the reasoning was insufficient. The flow meter had been functioning normally before. The problem was initially suspected to be a poor connection in the wiring, but no issue was found after several checks. Occasionally, the issue seemed to resolve when the wires were moved, but after a few cycles or hours, the issue resurfaced. By expanding the inspection area, the problem was finally identified as a loose connection between the converter and the sensor. This highlights the importance of thoroughly inspecting all connections to ensure reliable operation.