Electromagnetic flowmeter advantages and disadvantages

The main advantages of electromagnetic flowmeters are as follows:

1) The sensor structure of the electromagnetic flowmeter is simple, there are no moving parts in the measuring tube, and there are no throttling parts that hinder the fluid flow. Therefore, when the fluid passes through the flow meter, it will not cause any additional pressure loss, and is one of the lowest energy consumption flow meters in the flow meter.

2) The flow rate of fouling medium, corrosive medium and suspension liquid-solid two-phase flow can be measured. This is due to the unobstructed flow components inside the instrument measuring tube. The only contact with the measured fluid is the measuring tube lining and the electrode. The material can be selected according to the nature of the measured fluid. For example, polytetrafluoroethylene or Teflon liners can be used to measure a variety of corrosive media such as acids, alkalis, and salts; wear-resistant rubber liners are particularly suitable for measuring wear with solid particles. Larger slurry, cement slurry, etc. Liquid-solid two-phase flow, and various suspended liquids with fiber liquids and pulps.

3) The electromagnetic flowmeter is a kind of volume flow measuring instrument. In the measurement process, it is not affected by the measured temperature, viscosity, density of the medium (in a certain range). Therefore, after the electromagnetic flowmeter is calibrated by water, it can be used to measure the flow of other conductive liquids.

4) The output of the electromagnetic flow meter is only proportional to the average flow velocity of the medium being measured, and is independent of the flow state (laminar flow or turbulent flow) under a symmetrical distribution. Therefore, the range of the electromagnetic flowmeter is very wide, with a measuring range of up to 100:1, and some even reach a flowable range of 1000:1.

5) The electromagnetic flowmeter has no mechanical inertia and reacts sensitively. It can measure instantaneous pulsating flow, and can also measure the flow in both positive and negative directions.

6) The scope of the industrial electromagnetic flowmeter is very wide, from a few millimeters up to a few meters. Moreover, the real-time flow calibration equipment with a caliber of up to 3m in China has laid a foundation for the application and development of electromagnetic flowmeters.

The main drawbacks of electromagnetic flowmeters are still as follows.

1) It cannot be used to measure gases, steam, and liquids containing large amounts of gas.

2) It cannot be used to measure liquid media with very low electrical conductivity. For media such as petroleum products or organic solvents, electromagnetic flowmeters are still powerless.

3) Electromagnetic flowmeters for general industrial use cannot be used for measuring high-temperature media due to the restrictions of measuring tube lining materials and electrical insulating materials; if they have not been specially treated, they cannot be used for measurement of low-temperature medium to prevent condensation outside the measuring tube. (frosting) destroys insulation.

4) The electromagnetic flowmeter is susceptible to external electromagnetic interference.