Analysis of the faults that are prone to occur in electromagnetic flowmeters and how to deal with them
The electromagnetic flowmeter is an inductive instrument that measures the volume flow of the conductive medium in the pipe according to Faraday's law of electromagnetic induction.
After this technology has changed life, and smart products have adopted large-scale integrated circuits, there have been breakthroughs in the manufacture and use of electromagnetic flowmeters. Now the electromagnetic flowmeters all use single-chip embedded technology to realize digital excitation, and at the same time in intelligent electromagnetic flow The CAN field bus is used in the design.
There are no other components in the pipeline of the electromagnetic flowmeter, so in addition to measuring the flow of conductive fluids, it can also be used to measure the flow of non-conductive liquids of various viscosities (in which easily ionizable substances are added). Electromagnetic flowmeters are often used in the nuclear energy industry. At present, the domestic electromagnetic flowmeter technology has matured, and it has been widely used in chemical, water supply, petrochemical, paper, food, textile, metallurgy, environmental protection, water supply and drainage and other industries. Implement system control.
The advantage of the electromagnetic flowmeter is that the pressure loss is extremely small and the measurable flow range is large. The ratio of the maximum flow rate to the minimum flow rate is generally more than 20:1. The applicable industrial pipe diameter range is wide, up to 3m. The output signal and the measured flow rate are linear, and the accuracy is high. It can measure the conductivity of ≥5μs/cm. Fluid flow of acids, alkalis, salt solutions, water, sewage, corrosive liquids, and slurries, pulp, pulp, etc. But it cannot measure the flow of gas, steam and pure water.
The electromagnetic flowmeter will cause inaccurate measurement due to various faults during operation, so this phenomenon is generally divided into two categories during operation:
1. The failure of the flowmeter itself and the failure of components caused by damage;
2. Failures caused by changes in external conditions, such as flow distortion, deposition and scaling caused by improper installation.
Based on work experience, this article summarizes several types of common faults, analysis and corresponding processing methods, hoping to be helpful to users.
Fault 1: The liquid does not flow and there is an output reason analysis
1. There is an open circuit in the signal transmission cable connection with the converter; solution: connect the cable.
2. The connection between the signal cable and the electrode is broken; the solution: open the sensor and reconnect it.
3. The surface of the electrode is contaminated or an insulating layer is deposited; the solution: wipe the surface of the electrode first; 4. Connect the bottom line.
4. Poor grounding or open circuit; solution: connect the bottom line.
Fault 2: Analysis of the Cause of No Output in Liquid Flow
1. The two core wires of the signal transmission cable between the converter and the converter are reversed; solution: reverse the wire head;
2. The power supply is not connected or the contact is poor; solution: connect the power supply and keep the contact in good condition;
3. There is leakage in the sensor instrument pipeline, shell and end face; solution: repair the sensor.
Fault 3: Analysis of the Cause of Excessive Error
1. The zero point is too high; the solution: re-adjust the zero point;
2. Not completely filled with liquid; solution: improve channel conditions, the sensor is always filled with liquid;
3. The distortion of the power supply is too large; the solution: improve the conditions of the power supply and meet the normal working conditions;
4. Poor grounding; solution: connect the grounding wire.
Fault 4: Analysis of the reasons for unstable output
1. The flow field is unstable; the solution: transform the channel, or increase the installation of fake sensors;
2. The liquid passing through the sensor contains gas and large solid blocks; solution: check the wiring and connect the wiring;
3. Virtual connection of electrical connection; solution: connect the ground wire;
4. Poor grounding and electrode leakage; solution: repair the sensor.
With the continuous development and progress of modern science and technology, intelligence dominates the world. With the design of electromagnetic flowmeter and the application of new materials, its production process is becoming more and more mature, the protection level of the instrument is also increasing day by day, and the performance of electromagnetic flowmeter is more stable.
According to the investigation of the actual production situation, the electromagnetic flowmeter product itself rarely fails. Therefore, as long as we organize and investigate the various types of faults and their causes that occur in the electromagnetic flowmeter, and install and use them in strict accordance with the standards, routine maintenance of the electromagnetic flowmeter is carried out periodically. problem appear.
