Electromagnetic flowmeter as an effectively measure the volume flow rate of conductive media, its main components include sensors, flow conversion and processing instruments. And its main feature is that it has no throttling flow-resisting parts, it is not easy to block, has good corrosion resistance, and has a wide range of applicable media. The measurement accuracy is not affected by physical parameters such as temperature, viscosity, density, pressure, and specific gravity of the measured medium. A certain conductivity range is independent of the type of liquid being calibrated.
As a most widely used flow instrument,electromagnetic flowmeters are commonly used to measure conductive liquids suchas tap water, sewage, and seawater. Therefore, after running for a period oftime, it is easy to contaminate the electrode or to precipitate and foul in themeasurement tube wall. So the adhered scale layer in the measuring tube of theelectromagnetic flowmeter should be removed in time, otherwise the instrumentmay not work properly.
As a professional company specializing inthe production of electromagnetic flowmeter, in the years of providingcustomers with the installation and maintenance process, Sichuan VacordaInstrument summed up a set of most effective routine inspection of theelectromagnetic flowmeter sensor:
1. Sensorinspection
The required test equipment: A multimeter, a 500MΩ insulation resistance tester.
Inspection steps:
- When the pipeline is full of media, use a multimeter to measure theresistance value between terminals A, B, and C. The resistance between A-C andB-C should be approximately equal. If the difference is more than 1 time, itmay be the leakage of the electrode, it has the adsorption of condensed water inthe outer wall of the measurement tube or the junction box.
- When the liner is dry, use insulation resistance tester to measurethe insulation resistance between A-C and B-C (it should be greater than200MΩ). Then use a multimeter to measure the resistance of the terminals A, Band the two electrodes in the measuring tube (it should be short-circuitconnected). If the insulation resistance is very small, then the electrodeleakage, the entire flowmeter should be returned to the factory for repair. Ifthe insulation is reduced but there is still more than 50MΩ and the inspectionresult of step 3 is normal, the outer wall of the measuring tube may be damp,and the interior of the housing may be dried by a hot air blower.
- With a multimeter to measure the resistance between X, Y, if morethan 200Ω, the excitation coil and its lead wire may be open or poor contact.Remove the terminal board and check.
- Check the insulation resistance between X, Y and C, should be morethan 200MΩ, if there is a drop, use a hot air to dry the inside of the shell. Inactual operation, a decrease in coil insulation will lead to an increase inmeasurement error and the unstable output signal of the instrument.
- If it is determined that the sensor is faulty, contact themanufacturer of the electromagnetic flowmeter.
2.Conversion inspection:
If it is determined that theconverter is faulty, check with the manufacturer of the electromagneticflowmeter if there is no problem with the external cause. The manufacturersgenerally adopt the method of replacing circuit boards.
3. Themaintenance of the electrode
- Before using the electromagnetic flowmeter, use a standard pHsolution to calibrate the electromagnetic flowmeter. After the calibration,must clean the electrodes of the electromagnetic flowmeter with distilledwater, and then use the test liquid to clean again.
- When not use the electromagnetic flowmeter and remove its electrode,we must pay attention not to allow the touchpad of the electrode to collidewith a hard object. Otherwise, it will affect the use of the electrode.
- After the use of electromagnetic flowmeter, we must put theelectrode sets to on the electrode, and put some saturated solution, as long asguarantee the electrode bulb is wet, but remember not to put it in distilledwater.
- Keep the electrode clean, do not let it appearthe output short circuit on both sides, otherwise it will make the measurementis not accurate, affect the use of electromagnetic flowmeter.
Post time: 21-09-21