Electromagnetic flowmeter inspection has many elements

The structure of the electromagnetic flowmeter is composed of a sensor and a converter: the sensor is installed on the industrial process pipeline, converts the liquid volume flow into an induced potential signal, and transmits it to the converter; the converter converts the flow signal sent by the sensor Amplify and convert into standard electrical signal output to display, accumulate and adjust the flow value.

There are many contents for electromagnetic flowmeter inspection:

Flow sensor inspection: By inspecting the excitation coil and checking the excitation current measured by the converter to indirectly evaluate whether the magnetic field strength changes; Measure the electrode liquid resistance to evaluate the contamination of the electrode surface and the condition of the lining adhesion layer; check the insulation resistance of each part to determine the degree of deterioration of the parts and evaluate whether interference will be introduced. For pipelines with conditions that can stop the flow of media, the thickness of the electrode and lining attachment layer can be observed and measured to estimate the change in flow value caused by the change in flow area before and after cleaning the attachment layer.

Connecting cable inspection: Check the continuity and insulation resistance of each core of the signal line and excitation line, and check whether the grounding of each shielding layer is intact.

Converter check: A universal instrument and an analog annunciator matching the flow meter model are used instead of the sensor to provide the flow signal for zero adjustment and calibration. Calibration includes zero point check and adjustment, set point check, excitation current measurement, current/frequency output check, etc. It should be noted that the inspection items should be compared with the last inspection value (or factory value) to analyze whether there are changes or whether the changes meet the original measurement requirements.

Installation and debugging requirements for electromagnetic flowmeters:

The installation and debugging of electromagnetic flowmeters are more complicated than other flowmeters, and the requirements are more stringent. The transmitter and converter must be used together, and two different types of instruments cannot be used together. When installing the transmitter, from the selection of the installation location to the specific installation and debugging, the product instructions must be strictly followed. There should be no vibration or strong magnetic field in the installation location. During installation, the transmitter and pipeline must have good contact and good grounding. The potential of the transmitter is the same as that of the fluid being measured. During use, the gas remaining in the measuring tube must be exhausted, otherwise it will cause large measurement errors.