Advantages and disadvantages of electromagnetic flowmeters
Yokogawa electromagnetic flowmeter is a kind of flowmeter that is very commonly used now. The technology is relatively mature. AXF electromagnetic flowmeter is mainly used in chemical, paper, food, textile, environmental protection and other industries. It is mainly used to measure the flow of conductive fluids, which can be calculated with Supporting the realization of system control.
The most commonly used electromagnetic flowmeter selection here is water, sewage and other conductive liquids. The electromagnetic flowmeter has high measurement accuracy and is easy to install. It is a relatively good liquid flowmeter. Especially for measuring water and sewage, it can display instantaneous cumulative flow on site and output 4-20MA signal. Or RS485 signal. RS485 can be directly connected to the computer.
There are three main types of electromagnetic flowmeters: integrated electromagnetic flowmeter, split electromagnetic flowmeter, and insertion electromagnetic flowmeter. Each type of electromagnetic flowmeter has its own installation environment requirements, wiring requirements, etc., but generally electromagnetic flowmeters Flow meters have the following characteristics
1. The electromagnetic flowmeter has no moving parts and no blocking parts, which will not cause pressure loss, and will not cause problems such as wear and blockage. It is especially suitable for measuring ore pulp with solid particles, liquid-solid two-phase fluids such as sewage, and various viscous slurries. Also, because it has no moving parts in its structure, it can be made of electrodes by attaching a corrosion-resistant insulating lining and selecting corrosion-resistant materials, which has good corrosion resistance and can be used for the measurement of various corrosive media.
2. The electromagnetic flowmeter is not affected by the temperature, viscosity, density and conductivity of the measured medium (within a certain range) during the measurement process. Therefore, the electromagnetic flowmeter can be used to measure the flow of other conductive liquids only after being calibrated by water, without additional correction.
3. The electromagnetic flowmeter has a wide range, up to 1:100. In addition, the electromagnetic flowmeter is only proportional to the uniform flow rate of the measured medium, and has nothing to do with the axisymmetric activity condition (laminar or turbulent).
4. The electromagnetic flowmeter has no mechanical inertia, has a sensitive response, can measure the instantaneous pulsating flow, and has good linearity, so the measurement signal can be directly converted into a standard signal output by a converter.
Disadvantages of electromagnetic flowmeter:
Electromagnetic flowmeters cannot be used to measure gases, vapors, and liquids containing a large amount of gas. Electromagnetic flowmeters are susceptible to external electromagnetic interference.
At present, electromagnetic flowmeter cannot be used to measure liquid medium with very low conductivity. The conductivity of the measured liquid medium cannot be lower than 10-5 (S/cm), which is equivalent to the conductivity of distilled water. It is still powerless to petroleum products or organic solvents. Due to the limitation of the temperature of the insulating lining material of the measuring tube, the current industrial electromagnetic flowmeter cannot measure high temperature and high pressure fluids.
The electromagnetic flowmeter is affected by the flow velocity distribution. Under the condition of axisymmetric distribution, the flow signal is proportional to the average flow velocity. Therefore, there must be a certain length of straight pipe sections before and after the electromagnetic flowmeter.
