How to judge whether the electromagnetic flowmeter is good or the ultrasonic flowmeter is good? Today I will show you the good or bad of electromagnetic flowmeter and ultrasonic flowmeter.
The electromagnetic flowmeter is a flowmeter designed using the principle of Ferrari magnetic induction. The main structure of electromagnetic flowmeter is composed of magnetic circuit system, measuring tube, electrode, shell, lining and converter. From the physical properties, it has strong anti-interference ability and is not affected by the viscosity, density and pressure of the object. Impact. This kind of flowmeter is relatively common, and the production and maintenance technology is relatively mature. Its advantages are corrosion resistance, wear resistance, long service life, and secondly, it can carry out two-way measurement, which is convenient for operation. Electromagnetic flowmeters are now used in metallurgy, industry, chemical industry, agricultural irrigation, environmental protection, medicine and other fields. The most typical is to measure the volume flow of conductive liquid in a closed conduit.
However, the electromagnetic flowmeter cannot measure steam, gas, etc., so it is very limited. In the liquid with very low conductivity, the electromagnetic flow measurement effect is not good. . Electromagnetic flowmeter is a flowmeter that works based on the law of electromagnetic induction (cutting magnetic lines of force). Its characteristics are:
1. High measurement accuracy and good repeatability;
2. the price is proportional to the size of the pipe diameter;
3. The measured medium is required to have a certain conductivity.
Ultrasonic flowmeter uses ultrasonic waves to measure the liquid flow in the pipeline. Ultrasonic flowmeters have been widely used as early as the 1970s. Now its technology is more mature and its scope of application is wider. The biggest advantage of ultrasonic flowmeter is that it can check the size of fluid flow without touching the object to be measured. The advantage of this is that no matter what medium or pipe with large diameter, it will not affect the working efficiency of ultrasonic flowmeter. The gas and vapor that the electromagnetic flowmeter cannot detect can be detected by the ultrasonic flowmeter.
Features of ultrasonic flowmeter:
1. No moving parts, no pressure loss;
2. No requirement for fluid physical properties;
3. non-contact measurement;
4. The cost has nothing to do with the pipe diameter;
5. Easy to install, no need to stop.
Many people think that the electromagnetic flowmeter is a non-contact measurement method, or that the electromagnetic flowmeter has low requirements for straight pipe sections. It is wrong. This wrong understanding is often at the expense of accuracy. In practice, the accuracy of ultrasonic flowmeters can already achieve 0.5% accuracy, and many of its advantages will gradually be reflected in future industry applications. Of course, there are many people who will refute the many shortcomings of ultrasonic flowmeters, so I hope that when selecting models, you should clarify your application conditions, and then choose the appropriate flow meter according to the operating conditions. Choose instruments with different accuracy. Only an instrument that meets your actual work needs is a good instrument. There are many brands of electromagnetic flowmeters. Generally, their accuracy grades tend to be proportional to their prices. Ultrasonic flowmeters are also divided into multiple grades of brands, and their corresponding accuracy and reliability are also very different. Therefore, in the selection process of instruments and meters, it is necessary to base on their actual needs.
Recommendations on the choice between electromagnetic flowmeter and ultrasonic flowmeter should be mainly considered from the following aspects:
1. According to the nature of the fluid being measured, if the fluid is not conductive, you can only choose an ultrasonic flowmeter.
2. The measurement environment around the flowmeter, because the ultrasonic flowmeter is susceptible to electromagnetic wave interference, if there are objects emitting electromagnetic waves around the flowmeter, then it is not suitable to install the ultrasonic flowmeter.
3. According to the nature of the measurement, if the instantaneous flow is strictly required during the measurement, it is more suitable to install an electromagnetic flowmeter.
4. Ultrasonic flow meters are more recommended to be used at the more important flow detection points of large and medium calibers. The measured flow pipes should be of regular shape, uniform wall thickness, free of rust spots, precipitation, liquid accumulation, etc. (choose "with pipe section" as much as possible Form), otherwise the Reynolds number cannot be corrected.
5. Ultrasonic flowmeter can realize non-contact measurement. Generally, the correct selection of flow meters should be considered from the following five aspects: Performance requirements: accuracy, repeatability, range, and response time. Fluid characteristics: temperature, pressure, density, viscosity, corrosion and scaling, compressibility. Installation requirements: vertical, horizontal, straight pipe section, pipeline vibration, valve position. Environmental aspects: temperature, humidity, safety, electrical interference.