Electromagnetic flowmeters are widely used in many fields such as industrial production. However, sometimes the flow measurement may be inaccurate, which may affect the control of the production process and product quality. Let's discuss the solutions when the flow measurement of the electromagnetic flowmeter is inaccurate.
I. Check the State of the Fluid in the Pipeline
Whether the Fluid Fills the Pipeline
If the fluid in the pipeline fails to fill it completely, it will lead to measurement errors. For example, during some transportation processes, due to an unreasonable pipeline inclination or insufficient pumping capacity of the upstream pump, gas may exist in the pipeline in some periods, interfering with the normal measurement of the electromagnetic flowmeter. The pipeline layout should be checked to ensure that there is sufficient slope for the fluid to fill the pipeline smoothly. If necessary, adjust the parameters of the pump to enhance the pumping capacity.
Whether There Are Bubbles in the Fluid
When there are a large number of bubbles in the fluid, it will seriously affect the measurement accuracy of the electromagnetic flowmeter. For example, in some chemical production, chemical reactions may generate gas and mix it into the fluid. A gas separator can be installed in the pipeline to separate the bubbles in advance, or a special degassing device can be used to reduce the impact of bubbles on the measurement.
II. Examine the Electrode Condition
Electrode Contamination
After long-term use, the surface of the electrode may be contaminated by oil, impurities, etc., resulting in a change in the conductivity between the electrode and the fluid, thus affecting the measurement accuracy. For example, in the sewage treatment industry, dirt in the sewage easily adheres to the electrode. At this time, the electrode needs to be cleaned regularly. A chemical cleaning method can be used, and an appropriate cleaning agent should be selected to remove the contaminants on the surface of the electrode. However, attention should be paid to ensure that the cleaning agent does not corrode the electrode material.
Electrode Wear
Solid particles in the fluid or high-speed flowing fluid may cause electrode wear. In mining production, the scouring of the slurry will gradually wear the electrode. When the electrode is severely worn, it should be replaced in time. And consider installing a filter upstream of the pipeline to reduce the impact of solid particles on the electrode.
III. Check the Lining Condition
Lining Damage
If the lining is damaged, aged, etc., it will change the flow field distribution in the pipeline, thereby affecting the measurement accuracy. For example, under the working conditions of high temperature, high pressure or highly corrosive fluids, the lining is easily damaged. The integrity of the lining should be checked regularly. Once the lining is found to be damaged, the lining material should be replaced in time. And a more suitable lining type with temperature resistance, pressure resistance and corrosion resistance should be selected according to the actual working conditions.
IV. Troubleshoot the Converter Fault
Incorrect Parameter Settings
Incorrect parameter settings of the converter will lead to inaccurate measurement. For example, if the range is set too large or too small, the measurement result will deviate from the true value. It is necessary to re-check the process requirements and fluid characteristics and correctly set the range, damping time and other parameters of the converter.
Hardware Fault of the Converter
The electronic components inside the converter may malfunction, such as a decrease in amplifier performance or a damaged circuit board. The substitution method can be used. Replace the suspected faulty converter with a normal one and observe whether the measurement result returns to normal. If it is determined that there is a hardware fault in the converter, contact the manufacturer or professional maintenance personnel in time for repair or replacement.
When the flow measurement of the electromagnetic flowmeter is inaccurate, don't panic. Check the possible causes one by one according to the above steps and take corresponding solutions to ensure that the electromagnetic flowmeter can accurately measure the flow and ensure the smooth progress of the production process.
V. Consider External Interference Factors
Electromagnetic Interference
If there are strong electromagnetic interference sources such as large motors and transformers around the electromagnetic flowmeter, its measurement signal will be affected. For example, in the area where electrical equipment is concentrated in a factory, the electromagnetic environment is relatively complex. The signal cable of the electromagnetic flowmeter should be a shielded cable, and ensure that the shielding layer is well grounded. At the same time, filter the power supply of the flowmeter to reduce the impact of electromagnetic interference on the measurement.
Pipeline Vibration
Strong vibration of the pipeline may cause the sensor of the electromagnetic flowmeter to generate false signals. For example, the electromagnetic flowmeter installed near a compressor with large vibration is easily affected. Reinforcement measures can be taken for the pipeline, such as installing pipeline supports and shock-absorbing pads, to reduce the interference of pipeline vibration on the flowmeter.
