The English name for a flow meter is flowmeter. The National Committee for Terminology in Science and Technology defines it as: an instrument that indicates the measured flow rate (or) the total fluid volume within a selected time interval. Simply put, it's an instrument used to measure the flow rate of fluid in pipes or open channels. Today, we mainly want to share the causes and solutions for fluctuations in electromagnetic flowmeter readings. Generally speaking, abnormal fluctuations in the readings of an electromagnetic flowmeter may be due to:
1. Caused by installation at the highest end of the pipeline
2. Caused by surrounding interference, such as the noise from signals emitted by frequency converters, large motors, etc.
3. The liquid being tested was not completely filled.
4. Non-metallic pipes are not grounded.
5. The flow meter itself is damaged.
If an electromagnetic flowmeter exhibits abnormal fluctuations during measurement, the following checks and troubleshooting steps should be taken based on the specific circumstances. Firstly, if the flowmeter is installed at the highest point, a vent valve can be installed at the inlet to release any gas, which should resolve the measurement fluctuations. If the flowmeter is not installed at the highest point, it may be due to electromagnetic interference. In this case, the power supply should be disconnected and replaced. If the pipe is non-metallic, a grounding ring must be installed to ensure sufficient contact between the medium and the container.
There are two ways for bubbles to form in a liquid: they are drawn in from the outside and dissolved in the liquid (air) and transformed into free bubbles. If the liquid contains large bubbles, they can cover the entire electrode when passing through it, causing the flow signal input circuit to open momentarily, resulting in fluctuations in the output signal.
The simplest way to determine this is to cut off the excitation circuit current of the magnetic field when it shakes. If the instrument still displays an unstable reading, it's likely due to air bubbles. If you measure the electrode resistance with a pointer-type multimeter at this time, you'll find that the circuit resistance is higher than normal. However, this test requires extensive experience and data accumulated by professionals.
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