The lining material should be selected according to the corrosiveness, wear and temperature of the tested medium:
First, natural rubber (soft rubber)
1, better elasticity, wear resistance and tearing force
2, resistant to general weak acid, weak alkali corrosion
3. Water and sewage
Second, acid-resistant rubber (hard rubber)
It can withstand the corrosion of hydrochloric acid, acetic acid, oxalic acid, ammonia water, phosphoric acid and 50% sulfuric acid, sodium hydroxide and potassium hydroxide at normal temperature, but it is not resistant to corrosion by strong oxidants.
It can measure general acid, alkali and salt solutions.
Third, neoprene (Neoprene)
1, excellent elasticity, high tearing force, good wear resistance
2, resistant to general low concentration of acid and alkali, salt solution corrosion, but not resistant to oxidation of the medium, and temperature requirements <80 ° C;
It can measure water, sewage, mud and pulp.
Fourth, Polyurethane (Polyurethane)
1, excellent wear resistance
2, poor acid and alkali resistance, temperature requirements <40 ° C
Measure medium-strongly worn coal slurry, mud and slurry
Five, polytetrafluoroethylene (PTFE)
1. Boiling hydrochloric acid, sulfuric acid, nitric acid, aqua regia, concentrated alkali and various organic solvents
2, good wear resistance, poor bonding performance, temperature requirements -80 ~ +180 ° C;
Measuring concentration, concentrated alkali strong corrosive solution and sanitary medium
Daily maintenance (2)
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.
Electrode maintenance
1. Before using the electromagnetic flowmeter, first calibrate the electromagnetic flowmeter with a standard pH solution. 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 put it in distilled water. soak.
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.
In fact, there are still many ways to maintain the electrodes of the electromagnetic flowmeter. Everyone should pay more attention to the use process. Do not use the small negligence of the electromagnetic flowmeter in the future.
Several problems of solutions
Recalculating the differential pressure scale
Temperature and pressure compensation can only reduce the measurement error, not only can not solve the problem fundamentally, but also the measurement signal exceeds 20mA, resulting in steam leakage measurement. The transmitter measurement signal exceeds 20 mA, indicating that the actual measured differential pressure signal ΔP exceeds the design differential pressure value.
Increase temperature and pressure compensation
When the temperature and pressure of the steam change, the density of the steam changes, and the steam flow measurement produces an error. Measurement error can be reduced by temperature and pressure compensation. Since the temperature of the saturated steam is a single-valued function of the pressure, the temperature and pressure compensation of the saturated steam can be pressure compensated or temperature compensated. Because the pressure signal detection is sensitive and the compensation accuracy is high, it is compensated by pressure and realized by DCS.
Conclusion
Steam is a special medium. As the pressure and temperature change, the density of steam changes. Therefore, it is necessary to compensate for temperature and pressure. When the pressure and temperature fluctuation of the steam are not large, that is, when the operating condition parameters deviate from the design parameters and the influence on the measurement is small, the temperature and pressure compensation measures can achieve the purpose of accurate measurement. However, when the operating parameters deviate too much from the design parameters or the operating parameters fluctuate frequently and are too large, even with the temperature and pressure compensation, it is difficult to meet the measurement accuracy requirements. At this point, only differential pressure or flow can be recalculated for a particular throttling element.