Correct detection and troubleshooting methods and solutions for finding electromagnetic flowmeter faults
Electromagnetic flowmeter is a kind of instrument that effectively measures the volume flow of conductive medium. The main components include sensors, flow conversion and processing instruments. Its main features are unthrottled flow-blocking parts, which are not easy to block, have good corrosion resistance, and are suitable for a wide range of 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 one of the most widely used instruments in the flow measurement range, electromagnetic flowmeters are commonly used to measure conductive liquids such as tap water, sewage, seawater, etc., so after running for a period of time, it is easy to contaminate the electrode or precipitate and scale in the wall of the measuring tube. The fouling layer in the measuring tube of the electromagnetic flowmeter should be removed in time, otherwise the meter will not work properly. As a professional manufacturer of electromagnetic flowmeters, Sichuan Huikeda Instrument has provided a complete set of routine inspections of electromagnetic flowmeter sensors in the process of installation and maintenance for many years to avoid the most effective way to avoid failures. :
The most common situation we encountered was: the electromagnetic flowmeter started to be put into operation or was put into operation for a period of time and found that the instrument is not working properly. If this happens, the external condition of the flowmeter should be checked first. Good, then check if the pipe is leaking or in a non-full pipe state, if there are air bubbles in the pipe, whether the signal cable is damaged, and whether the converter output signal (ie, the rear instrument input circuit) is open. Follow this correct procedure and remember to blindly disassemble the flowmeter.
Electromagnetic flowmeter sensor inspection
Test equipment to be prepared: one multimeter, one 500MΩ insulation resistance tester.
Test check steps:
(1) When the pipeline is filled with medium, measure the resistance between terminals A, B and C with a multimeter. The resistance between A-C and B-C should be equal. If the difference is more than 1 time, there may be leakage of the electrode, condensation on the outer wall of the measuring tube or the junction box.
(2) In the case of lining drying, measure the insulation resistance between A-C and B-C with MΩ meter (should be greater than 200MΩ). Then use a multimeter to measure the resistance of the two electrodes in terminals A and B and the measuring tube (should be in short-circuit communication). If the insulation resistance is small, indicating that the electrode is leaking, the entire flowmeter should be returned to the factory for repair. If the insulation is reduced but there is still more than 50 MΩ and the inspection result of step (1) is normal, the outer wall of the measuring tube may be damp, and the inside of the outer casing may be dried by a hot air blower.
(3) Use a multimeter to measure the resistance between X and Y. If it exceeds 200 Ω, the excitation coil and its lead wire may be open or poorly connected. Remove the terminal block check.
(4) Check the insulation resistance between X, Y and C, which should be above 200 MΩ. If it is lowered, dry the inside of the casing with hot air. In actual operation, the decrease in coil insulation will result in increased measurement error and unstable instrument output signal.
(5) If it is determined that the sensor is faulty, please contact the manufacturer of the electromagnetic flowmeter. The general site cannot be solved and needs to be repaired by the manufacturer.
Electromagnetic flowmeter converter check
If it is determined that the converter is faulty, if there is no problem in checking the external cause, please contact the manufacturer of the electromagnetic flowmeter. The manufacturer will generally solve the problem by replacing the circuit board.
Electromagnetic flowmeter electrode maintenance
1. Before using the electromagnetic flowmeter, the standard pH solution should be used to calibrate the electromagnetic flowmeter. Before the calibration, before operation, you must pay attention to clean the electrode of the electromagnetic flowmeter with distilled water, and then clean the electrode again with the test liquid.
2. If you do not use the electromagnetic flowmeter, when you want to remove the electrode of the electromagnetic flowmeter, you should be careful not to let the electrode of the electrode collide with the hard object, otherwise the damage will affect the use of the electrode.
3. After using the electromagnetic flowmeter, you should put the electrode of the electromagnetic flowmeter on the sleeve, and put less saturated solution inside, just make sure that the bulb of the electrode is wet, but remember not to soak it in distilled water.
4. It is usually necessary to keep the electrode clean and do not let the output on both sides of it appear a short circuit. Otherwise, the measurement will be inaccurate and affect the use of the electromagnetic flowmeter.
The ones we introduce for you are only a small part of the skills in our work. There are still many ways to maintain the electrodes of the electromagnetic flowmeter. Everyone should pay more attention to the use process, and more summed up. After all, only through their own practice. It is effective to find out the methods that are summed up. The daily maintenance of production should be good at observation, good at analysis, and maintenance work must be carried out in accordance with this correct procedure. Do not cause damage to the electromagnetic flowmeter because of a little negligence. As a result, it will not work properly in the future.