If the materials measured by the wheel flowmeter are easy to contaminate the electrode or settle and deposit in the measured wall thickness, the scale shall be removed and cleaned on time.

The controller shall check whether the steam flowmeter is in good condition, whether the switch power supply is good, whether the pipeline is leaking or not, whether there is bubble in the pipeline, whether the communication cable is damaged, and whether the converter output data signal (i.e. the back position instrument is keyed in control Loop) is it leading the way. Remember to blindly follow the wind to disassemble the steam flowmeter.

Testing equipment: one 500m Ω insulation layer measuring instrument and one digital multimeter.

Test steps:

(1) When the pipeline is filled with material, use a digital multimeter to measure the resistance between terminal blocks a, B and C. the resistance between a-c and B-C should be as large as the same. If the difference is more than 1 time, it may be that there is water leakage in the electrode, condensation water absorption on the surface of the measuring tube or in the terminal block.

(2) Under dry condition of lining, use M Ω meter to measure the grounding resistance between a-c and B-C (it should be more than 200m Ω). Then use the digital multimeter to measure the resistor between the terminals a and B and the two electrodes in the measuring tube (it should be in the case of short circuit fault connection). If the grounding resistance is small, it indicates that the electrode is leaking, the whole set of steam flowmeter shall be repaired and repaired. If the insulating layer is reduced to a certain extent but still above 50m Ω, and the inspection results of process (1) are all normal, it may be that the surface of the measuring pipe is damp, and the air dryer can be used to dry the inner part of the shell.

(3) Use a digital multimeter to measure the resistor between X and Y. if it exceeds 200 Ω, the excitation coil and the grounding wire of the transformer will lead or loosen. Remove the terminal board for inspection.

(4) Check the grounding resistance between X, y and C, which should be above 200m Ω. If there is a certain reduction, use warm air to dry the inside of the enclosure. In the specific operation, the decrease of the dielectric strength of the electromagnetic coil will cause the measurement deviation to expand and the output data signal of the instrument to be unstable.

(5) If the controller is judged to be faulty, please contact the manufacturer of electromagnetic flowmeter. Generally, it can not be handled on the spot, so it is necessary to go to the manufacturer for maintenance.

If it is judged that the converter of rotameter is faulty, please contact the manufacturer of electromagnetic flowmeter in case of all normal conditions due to external reasons. Generally, the manufacturer will replace the PCB circuit board. Converter inspection

Maintenance of electrode

1. Before applying electromagnetic flowmeter, add standard pH value water solution to calibrate electromagnetic flowmeter. After calibration, before actual operation, we must pay attention to clean the electrode of electromagnetic flowmeter with pure water first, and then clean the electrode again with measuring solution.

2. If the electromagnetic flowmeter is not used and the electrode of the electromagnetic flowmeter is to be taken out, we should pay attention not to let the hand sensor of the electrode collide with the hard block, otherwise, if there is damage, it will endanger the application of the electrode.

3. After the application of the electromagnetic flowmeter, we need to cover the electrode of the electromagnetic flowmeter, and put less saturated solution inside. If we want to ensure that the electrode bulb is wet, we can do so, but remember that it is not necessary to put it into pure water to soak.

4. Pay attention to keep the electrode clean at ordinary times, and do not let the output on both sides of it have short circuit fault, otherwise it will cause no measurement and harm the application of electromagnetic flowmeter.

In fact, there are many ways to maintain the electrode of orifice flowmeter. We need to pay more attention to the whole process of application, so we don't need a little carelessness to cause that electromagnetic flowmeter can't be used normally in the future.

1. Fault analysis during regulation period

The fault in the regulation period generally occurs in the instrument installation and regulation link. Once cleared, it is not easy to reoccur under the same standard later. The common failure of regulation period is caused by improper installation, natural environment and hydrodynamic characteristics.

1. Installation level

Generally, the fault is caused by the wrong installation position of electromagnetic induction air flow meter. Generally, if the controller is installed on the pipeline which is easy to accumulate steam, or installed on the vertical pipe from top to bottom, it will exhaust completely; or if there is no back pressure behind the sensor, the hydrodynamics will exhaust the air immediately and produce the non full pipe in the measuring pipe.

1. Natural environment

Generally, it is mainly influenced by stray electric flow of pipeline, strong radio wave in indoor space, electromagnetic field of large and medium motors, etc. In general, the effect of stray current flow on the pipeline can be satisfied by using excellent independent protective grounding. However, if strong stray current flow is encountered (such as the pipeline in the electrolysis workshop, sometimes the AC current potential value VPP of magnetic induction on two electrodes can reach 1V), additional countermeasures and insulation layer of air flow meter and pipeline need to be adopted. The influence of indoor space radio wave is generally introduced by communication cable, and single-sided or double-layer shielding is generally used for maintenance.

1. Fluid mechanics

The fine bubbles with uniform distribution in the measured liquid generally do not harm the normal operation of electromagnetic flowmeter, but with the expansion of bubbles, the

The output data signal of the meter will fluctuate. If the bubble is big enough to cover all the electrode surface, the electrode control circuit will be short circuited for a moment along with the bubble passing through the electrode, which will cause the output data signal to fluctuate even more.

When the electromagnetic flowmeter of the high-frequency waveform excitation regulator measures the slurry with too many solid components, the slurry noise will also be caused and the output data signal will fluctuate.

In the measurement of mixed substances, if the total amount of 

Improper selection of electrode raw materials and tested materials will also endanger all normal measurement due to oxidation or electrode state. Electrode raw materials shall be properly selected according to instrument use or relevant guidelines.

1. Failure during operation

The fault in operation period is the fault that occurs after the electromagnetic flowmeter has been adjusted and operated normally for a period of time. The common fault foundation in operation period is caused by the factors such as adhesion layer of air flowmeter inner cavity, severe strike of lightning and transformation of natural environment standard.

1. Adhesion layer of controller inner cavity

Because the electromagnetic flowmeter is often used to measure the fluid dynamics of the smudge, after a period of operation, the sticking layer will always accumulate in the inner cavity of the controller, resulting in the failure. This failure is usually caused by the high or low conductivity of the adhesive layer. If the accessory is a cable sheath, the electrode control circuit will be short circuited, and the instrument cannot work normally; if the conductivity of the adhesive layer is obviously higher than that of hydrodynamics, the electrode control circuit will be short circuited,

The instrument can not work normally. Therefore, the sticking crud layer in the measuring pipe of electromagnetic flowmeter should be eliminated immediately.

1. Severe lightning strike

It is very easy to induce high voltage and surge current in the instrument line by lightning stroke, which will destroy the instrument. It is imported according to the power plug or excitation coil or the total flow power line between the controller and the converter, especially the main control room power plug.

1. Transformation of natural environment standards

During the regulation period, because the natural environment standard is good (for example, there is no interference signal), everything in the operation of the steam flowmeter is normal, it is usually very easy to carelessly install the standard (for example, the grounding device is not very good). In this kind of situation, once the natural environment standard changes, new interference signals (such as arc welding on the pipeline around the steam flowmeter, installation of large transformers around the flowmeter, etc.) will appear in the operation period, which will immediately affect all normal operation of the instrument, and the output data signal of the steam flowmeter will immediately fluctuate.

General failure

Diagnosis and solution of typical faults

1. No total flow output. Check if there is any fault in one part of the switching power supply, check if the power supply voltage is normal; check if the fuse is connected; check if the arrow symbol of the controller is consistent with the inflow of fluid mechanics, if not, replace the installation position of the controller; check if the controller is filled with fluid mechanics, if not, dismantle and replace the pipeline or install vertically.

2. The data signal becomes smaller and smaller or suddenly decreases. Check whether the insulating layer between the two electrodes is damaged or short circuited. The resistance between the two electrodes is normal in the middle of (70-100) Ω. The inner cavity of the measuring tube will accumulate stains. Clean and scrub the electrodes to avoid scratching the lining. Check whether the inner lining of the measuring pipe is damaged. If it is damaged, it should be replaced.

3. If the zero point is not stable, check whether the substance is filled with the measuring tube and whether there are bubbles in the substance. If there are bubbles, the degasser can be modified upstream and downstream. If the level installation can be changed to vertical installation. Check whether the instrument grounding device is intact. If it is not good, carry out three-level grounding device (grounding resistance ≤ 100 Ω). Check whether the conductivity of the substance is not less than 5 μ s / cm. Check the substance If it is deposited in the measuring pipe, pay attention not to scratch the lining when eliminating it.

4. The marked value of total flow does not conform to the specific value. Check whether the hydrodynamics in the controller fills the pipe and whether there are bubbles. If there are bubbles, the degasser can be modified upstream and downstream. Check whether the grounding devices are in good condition. Check whether there are valves upstream and downstream of the steam flowmeter. If there are any, move them to the middle and downstream or make them fully open. Check whether the measurement range of the converter is set properly. If not, set the appropriate measurement range again.

5. The range fluctuates in a certain section. Check whether there is any change in the natural environment standard, such as new interference signal and other magnetic source or vibration endangering the normal operation of the instrument, immediately eliminate the influence or move the steam flowmeter; check and test the communication cable, and use the insulating tape to carry out the top solution, so that the transmission line, the inner shield, the outer shield and the middle of the cover do not touch each other.

The hydrodynamics of measuring the total flow with electromagnetic flowmeter must be conductive, so the non-conductive chemical substances such as steam, steam, raw oil, copper propionate can't measure the total flow with electromagnetic flowmeter.

Operational failure

After the initial adjustment and all normal operation for a period of time, the common failure causes are: adhesion layer of air flow meter inner cavity, lightning strike, natural environment standard change.