Customers often call to ask us why your electromagnetic flowmeter is inaccurate or drifting? When encountering this situation, we will analyze and explain for customers from the following points:1. The cause of the failureThe instability of the zero point of the electromagnetic flowmeter can generally be summarized as five reasons for the failure:(1) The measuring pipe is not filled with liquid or the liquid contains air bubbles; (2) Subjectively think that the liquid has no flow but there is actually a small flow; in fact, this is a misunderstanding of the flow of the liquid, not a malfunction of the electromagnetic flowmeter; (3 ) Improper grounding of the sensor due to external interference such as stray current; (4) Causes of liquid (such as liquid conductivity uniformity); (5) Decreased signal circuit insulation.2. Failure inspection and measures1. The pipeline is not filled with liquid or the liquid contains air bubbles. This type of fault is mainly caused by poor pipe network engineering design or imperfect related equipment. 2. There is a small amount of flow in the pipeline. Subjectively, there is no flow in the flow sensor, but there is actually a small amount of flow. The main reason for this type of failure is the poor tightness of the stop valve of the pipeline, and the small leakage detected by the electromagnetic flowmeter is mistaken for the zero point change or zero point instability. It is often encountered that the valve is not fully sealed due to the long-term use of the valve or the liquid is dirty, especially for large valves. Another common reason is forgetting to close branch valves outside the main pipeline. Sometimes, it is difficult to confirm that there is no flow in the piping system on site. 3. Observe whether there is a leak. 4. Imperfect grounding The influence of external interference such as pipeline stray current mainly depends on the good grounding protection of the electromagnetic flowmeter. Generally, the grounding resistance is required to be less than 10Ω, and it is necessary to ensure that it does not share the grounding with other motors and appliances. If a good environment cannot be ensured, the instrument will malfunction, and checking again at this time will cause a lot of trouble.
Post time: 21-09-21