Several key points to pay attention to when purchasing domestic electromagnetic flowmeter products

Since the first electromagnetic flowmeter in the industrial field came out in 1953 , after more than half a century of development, it has not only matured in production technology, but also developed various supporting technologies. Following the modern information process, electromagnetic flowmeters have made great progress in data processing and display methods. I believe that with the advancement of future technology, electromagnetic flowmeters, as a type of instrument with huge industrial production, will definitely have a broader development space.
 
At present, in China, electromagnetic flowmeter technology is relatively mature, and the products manufactured are basically stable and reliable. Many well-known domestic brands have good user feedback during use. How to buy products with reliable quality and stable performance, and determine the key points of the electromagnetic flowmeter's performance. As a manufacturer specializing in electromagnetic flow, Runzhong Instrument Technology Co., Ltd. has summarized the following points based on many years of manufacturing, installation and maintenance experience:
1. Production. Make sure that the electromagnetic flowmeter winding coils are all made of copper wire. Many small factories do not use copper wire to save money, and many owners have encountered it.
2. Factory test. Does the factory have pressure test equipment and measurement calibration devices, and whether the measurement calibration device meets national standards.
3. Performance hard indicators. Mainly look at how much the manufacturer's electromagnetic flowmeter can measure the minimum conductivity of the medium. After all, there are many media in the chemical industry with very low conductivity; secondly, look at the electrode scaling maintenance method; and many chemical media are corrosive, the manufacturer's electrode and lining selection scheme; finally, look at the accuracy level and the instantaneous and cumulative flow display panel window, as well as the explosion-proof level.
4. See if the product's debugging and maintenance is simple and easy to operate.
Look at the manufacturer's strength and after-sales service and the price of spare parts replacement
 
in the future. Electromagnetic flowmeters sometimes fail due to special reasons during application, making it impossible to measure. Therefore, we must eliminate them in time to ensure their application. However, if there is a problem with the electromagnetic flowmeter in operation, in order to ensure that it does not affect daily production after the fault is repaired, we should also calibrate it online, namely:
1. Test the safety insulation and copper resistance of the electromagnetic flowmeter excitation coil. The safety insulation should be greater than 20MΩ. Under the same ambient temperature, the copper resistance should be the same as the original factory value.
2. Test the resistance of the electromagnetic flowmeter sensor electrode to ground. If the resistance value is between 2-20kf and is accompanied by discharge, it is best if the resistance of the two electrodes is close.
3. Test the excitation current of the electromagnetic flowmeter converter, observe the value of its output and the original current of the converter, and the error should not exceed ±0.25mA.
4. Test the analog output and frequency output of the electromagnetic flowmeter converter, observe its linear change, and calculate its maximum linear error, which should not exceed ±0.5%.
5. For electromagnetic flowmeters above DN1200mm, the driving level NB should be tested, and the current error should not exceed 12mA.
The above is the method for online calibration of electromagnetic flowmeters. I hope it will be helpful to everyone.