What causes the sewage flow meter to not work?

1, lightning strike
Lightning strikes induce transient high voltages and surge currents in the line, and entering the meter can damage the meter. There are three ways to introduce the lightning damage meter: the power line, the flow signal line between the sensor spoon converter and the excitation line. However, from the analysis of damaged components in lightning faults, the induced high voltage and surge currents that cause faults are mostly introduced from the control room power line, and the other two approaches are less. It was also learned from the scene of the lightning strike that not only the electromagnetic flowmeter was faulty, but also other instrumentation in the control room often had lightning strikes at the same time. Therefore, the user must know the importance of setting up the lightning protection facilities of the control room instrument power cord.
2. Changes in environmental conditions
The main reason is the same as the fault environment in the debugging period of the previous section, except that the interference source does not appear during the debugging period and then intervenes during the operation. For example, an electromagnetic flowmeter with unsatisfactory grounding protection has normal operation due to no interference source during commissioning. However, new interference sources (such as pipelines near the measuring point or pipeline welding) interfere with the normal operation of the instrument during operation. , the output signal fluctuates greatly.
3. Inner wall adhesion layer
 Since the electromagnetic flowmeter measures much more than the other flow meters when measuring the suspended solid phase or the dirty body, the probability of failure of the inner wall adhesion layer is relatively high. If the electrical conductivity of the adhesion layer is close to the liquid conductivity, the instrument can output the signal normally, but only change the flow area to form a hidden fault of the measurement error; if it is a high conductivity adhesion layer, the electromotive force between the electrodes will be short-circuited; if it is an insulating adhesion layer The surface of the electrode is insulated to disconnect the measuring circuit. The latter two phenomena will make the meter inoperable.