Electromagnetic flowmeters regularly check the instrument, which is a must for every instrument user to ensure the normality of daily production. Electromagnetic flowmeters have been widely used in the industry, especially in the sewage industry. They have gained a lot of experience in terms of use and maintenance. Let us share with you:
Electromagnetic flowmeters are mainly flow control in industrial applications, and the measured fluids are corrosive and abrasive. In practical applications, the failure of the electromagnetic flowmeter is mostly caused by corrosion leakage, insulation degradation, electrode contamination or foreign matter adhesion.
The purpose of the daily inspection of the electromagnetic flowmeter is to ensure or prove that the electromagnetic flowmeter is operating under controlled conditions. The daily inspection methods generally include online inspection and offline inspection, mainly to verify whether the flow measurement value of the electromagnetic flowmeter meets and maintains the expected measurement requirements.
The traditional periodic maintenance check of the electromagnetic flowmeter is to remove the flow sensor from the pipeline and check it, and then perform flow calibration. In order to reduce the flow sensor to remove the damage lining from the pipeline, first measure the insulation resistance on the pipeline to infer whether there is any abnormality, and then decide whether to remove the pipeline inspection or the actual flow calibration.
First, the electromagnetic flowmeter can be verified by an online check for abnormalities. Check the flow sensor and converter separately for the pipeline that cannot stop the flow of the medium, use the analog annunciator and other general-purpose instrument to test the converter with high calibration accuracy (depending on the accuracy of the analog annunciator), and the sensor inspection with the test electrode Inductive resistance, check the excitation coil including the insulation resistance and copper resistance of the excitation connection cable, as well as the indirect method of checking the excitation current output from the converter and checking the magnetic field strength. For pipelines that can stop the flow of media, you can enter the hole from the vicinity of the sensor, check the electricity level and liner contamination, deposition and clean.
Second, the company can conduct a comprehensive inspection of the electromagnetic flowmeter every year. The inspection contents are: visual inspection, converter characteristic test, measurement value calibration, measurement of voltage of each part, measurement of insulation resistance, confirmation of circuit, etc. It is very important to adjust the zero point due to the zero drift of the meter check adjustment ("online zero adjustment" must stop the measured medium from flowing, which is not easy to do). Therefore, the online inspection often omits the inspection including the operation of the sensor, and only implements the calibration of the converter, so as to compare the online inspection result with the historical data to determine whether the instrument continues to be used, repaired or updated, and the sensor is insulated according to the measured excitation coil. The degree of deterioration determines whether it is updated or not.